Pistons & Rings — DRIVING EFFICIENCY in ENGINES

www.autotechreview.com October 2014 | Volume 3 | Issue 10 Now, Also available on

It’s on 14 Interview Ravindra Pisharody, Executive Director, CV Business Unit, Tata Motors

18 teCHNOLOGY FORESIGHT Trends In Lightweighting of Bevs: A Review of Strategies – Part II

60 new Vehicle Maruti Suzuki Ciaz – Setting The Sedan Gameplan on Track

pistons & rings —

driving efficiency in engines Powered by MM Auto_New_ with new logo.indd 1 24-04-2014 10:11:38 Editorial

VOTE OF CONFIDENCE

Dear Reader,

The past fortnight has been one of historic firsts! India achieved what no other nation in the world had managed to in their first attempts – the Mars Orbiter Mission (MOM) or ‘Mangalyaan’, as it was named, entered the Martian orbit in its first attempt, giving the Indian Space Research Organisation (ISRO) a place in global space history.

The success of Mangalyaan is a huge vote of confidence to the Indian space community, considering it was an acutely complex mission. What makes this an incredible feat is also the fact that this has been the least expensive space mission to Mars in recent times. Consider the numbers: India spent just $ 74 mn as against the US National Aeronautics and Space Administration’s $ 671 mn – a staggering one-ninth of what the US spent!

To put things in perspective, Mangalyaan cost a quarter less than the money spent to make the 2013 science fiction thriller, Gravity. Even Prime Minister Narendra Modi, in his speech at the Madison Square Garden, New York recently, said in a light hearted manner that the per km cost to Mars was cheaper than a km worth of an auto-rickshaw ride in India.

The other most remarkable thing about Mangalyaan’s success is that it was made entirely with home-grown Indian technologies. A lot of technologies were reused from ISRO’s past missions. Many experts acknowledged the fact that the cheap indigenous technology came out of sheer necessity.

That, in fact, has been a mantra with the Indian industry – a manufacturing philosophy that has resulted in many successes across industries. The Indian industry has come to be known for its frugal approach to manufacturing. There are myriad examples in the automotive industry as well, be it in terms of products or processes.

The Mangalyaan mission is no mean engineering feat. The ISRO should now expect the world to queue up to not just use its expertise, but to learn prudence in engineering and innovation. In fact, it should offer tremendous boost to the entire Indian engineering community, which has strong global credentials already. This is yet another feather in India’s engineering cap.

Deepangshu Dev Sarmah Editor-in-Chief New Delhi, October 2014

@deepangshu autotechreview.com October 2014 Volume 3 | Issue 10 1 Cover Story pistons & rings — driving EFFICIENcy in engines

24, 30, 36, 42 | The demand for more at less is a term well understood by automotive engineers, as efficiency and power continue to become a common offering now. Pistons and rings, which to the naked eye haven’t changed much over the decades, have undergone a phenomenal change in reality. They’re lighter, yet stronger and engineers continue to push the boundaries further as you read this. Keeping in mind their critical role for any engine, Auto Tech Review, in this issue, takes a look at the technical developments taking place in this space.

guest commentary

12 Driverless Cars: Truly ‘Auto’mobile RAJEEV SINGH, Partner and Head of Automobile Sector, KPMG in India

INTERVIEW

14 “2015-16 Could See Recovery of The Indian Automotive Industry” Ravindra Pisharody, Executive Director, CV Business Unit, Tata Motors

2 contents

NEWS Cover Story

4 Interactions 24 System Comparison of Steel & 54 Volkswagen Polo GT – All-Round 7 Events Aluminium Pistons for PC Functional Capability 10 News Diesel Engines Simon Schneider, Kai Schreer, SHOPFLoOR Holger Ehnis, Stefan Spangenberg TECHNOLOGY FORESIGHT 56 Continental Automotive – Aiming 30 Lower Friction Losses with Market-Specific Localisation 18 Trends In Lightweighting Of Bevs: New Piston Ring Coating A Review Of Strategies – Part II Marcus Kennedy, Steffen Hoppe, New vehicle Suresh Babu Muttana, Rakesh Kumar Dey, Johannes Esser Arghya Sardar 60 Maruti Suzuki Ciaz – Setting The 36 Gas-Lubricated Mechanical Face Rings Sedan Gameplan on Track

For CO2 Reduction Sören Neuberger, Eberhard Bock, DECODING TECHNOLOGY Habil. Werner Haas, Klaus Lang 64 Pistons & Rings – Prime Movers 42 Aspects of Piston Material Choice Arun Jaura for Diesel Engines Arnd Baberg, Marcus Freidhager, Harald Mergler, Klaus Schmidt others

01 Editorial technology 03 Imprint

46 Greater Efficiency Thanks to Mild Hybrid Integrated Approach Friedrich, Thomas Knorr, Sven Hager, Markus Kneissler

52 Battery Show Votes In Favour of A Lithium-Ion Future follow us on @autotechreview1 Cover Figure © Goruppa/iStockphoto.com

Imprint

Editorial & Business Office: Editor-in-Chief: Deepangshu Dev Sarmah Publisher & Managing Director: Springer India Pvt Ltd [email protected] / @deepangshu Sanjiv Goswami 7th Floor | Vijaya Building | 17, Barakhamba Road Assistant Editor: Arpit Mahendra For Editorial Contribution, write to the Editor-in-Chief at New Delhi – 110001 | India [email protected] / @arpitmahendra3 [email protected] + 91 11 4575 5888 (P) | +91 11 4575 5889 (F)

Senior Correspondent: Naveen Arul (Bangalore) For Advertisements, write to Manager – Sales at Auto Tech Review (ATR) is a monthly magazine focussed on automotive technology, and appears 12 times a year. Views and opinions expressed in this magazine are not necessar- [email protected] / @naveenarul [email protected] ily those of Springer India Pvt Ltd. No part of this magazine can be reproduced in any form, including photocopies and information retrieval systems, without the prior written permis- sion of the publisher. Springer India Pvt Ltd Limited reserves the right to use the informa- Manager – Sales: Sudeep Kumar For Subscription orders and reader registrations, tion published herein in any manner whatsoever. [email protected] please visit www.autotechreview.com Printed and Published by Sanjiv Goswami on behalf of Springer India Pvt Ltd. Printed at Gokul Offset, Okhla Industrial Estate, Phase – I, New Delhi and published at Springer India Senior Executive – Ad Sales: Pramodh R (Bangalore) Or, contact Manager – Sales at Pvt Ltd, 7th Floor, Vijaya Building, 17, Barakhamba Road, New Delhi. [email protected] [email protected] ©2013, Auto Tech Review

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autotechreview October 2014 Volume 3 | Issue 10 3 INTERACTION MICHELIN, PTC

MICHELIN | MATERIAL USAGE TO CHANGE, NOT COMPOSITION

Reduce, Reuse, Recycle and Renewable. In line about the question of shifting the load from one with the idea of Reduce, Michelin is making con- natural source to another. Aimon’s response to it stant efforts to develop lighter tyres, which last was that with the growing demand for tyres, the longer as well, said Aimon. Making these tyres a need for “natural rubber”, i.e. polyisoprene-based catalyst for higher fuel-efficiency, in tandem with elastomer will continue to grow in the long-term. the mentioned initiatives, leads to reduction in It is hence necessary to find additional supply consumption of natural resources. Reuse covers possibilities for it where the Hevea (type of rubber the actions of repairing, re-grooving and recap- tree) can grow. A diversification is also necessary ping, all of which lead to longer use of tyres and to find additional capacities in the long-term for lower consumption of rubber. Recycle and Renew- bio-based polyisoprene. As a matter of fact, sug- able, as their name suggests ensure that materi- ar-based polyisoprene will not replace Hevea- als aren’t wasted, leading to a controlled usage of based polyisoprene in the future, but it will be an new materials. additional source for polyisoprene, he added. In order to further improve its approach to green FUTURE ACTIONS credentials, Michelin had recently announced the Depleting natural reserves, impact on human acquisition of a significant minority stake in Sym- health and a changing climate are some of the The magnitude of raw material consumption by bioFCell, a France-based developer of fuel-cell key reasons forcing industries to innovate envi- the global tyre industry is huge, clearly reflected technology. Through this partnership, Michelin will ronmentally-friendly products and production pro- by these spectacular numbers. Globally, the in- be able to help the fuel-cell company in putting cesses. One key automotive component, which dustry consumes about 32 mn tonnes of raw ma- its plans in industrial production, while it stands uses considerable amount of natural resources, is terial, of which India presently accounts for about to benefit from an increased role in developing the tyre with about 75 % of it made from fossil- 1.8 mn tonnes only. In the long-term though, sustainable mobility, Aimon said. Michelin itself is based raw materials. And this has been a subject India’s consumption will increase to about 4 %. no stranger to the fuel-cell technology and has of research for most tyre makers today. We recent- Looking at such constantly-increasing demand, been actively working on it since a long time. ly spoke to Dominique Aimon, Vice-President, it’s imperative that each gram of rubber is used in Technical & Scientific Communication, Michelin the best way possible, noted Aimon. One such ini- FUTURE OF TYRES to understand the work being done by Michelin in tiative is the Tire Recycling Project (TREC), which order to lower the burden of tyres on nature. enables manufacture of new tyres from raw mate- There are numerous experiments being done by rials sourced from used tyres. Two methods, which tyre makers across the globe in pursuit of a better 4R STRATEGY achieve 100 % recycling of tyres, are TREC Re- tyre on all accounts. Some of these involve usage generation and TREC Alcohol Recycling Program. of new and artificially-engineered materials in To cut down its dependence on nature, Michelin Another potential Michelin is looking at is of using order to reduce the usage of natural materials. follows a 4R strategy to manufacture tyres – bio-isoprene sourced from sugarcane, bringing Unfortunately, most of these experiments are in their infant stages and will need a long-time to 75% of tyre Raw materials are fossil based turn into production reality, if successful. It was hence crucial for us to understand from Aimon, what the future tyre would be made of. Metalic cables He made it clear that he doesn’t expect huge Natural Rubber changes in the global composition of tyres over the next 20 or 30 years. This means that polyiso- Textile cords prene, synthetic rubbers based on butadiene, re- inforcing elements, etc., will continue to be used in a similar manner. However, the materials used Chemical will certainly be different. For instance, the products current elastomers for synthetic rubber would be replaced by functional elastomers and new rein- forcing fillers will also arrive. In the end though, the global proportion of the elements is not going to change drastically, he added. Carbon black Synthetic Rubber

Silica Text: Arpit Mahendra

4 www.autotechreview.com PTC | IoT, MBSE TECHNOLOGIES ARE THE WAY OF THE FUTURE

PTC, a leader in providing technology solutions and systems and software engineering applications. design software, has moved its focus more towards Atego is currently being integrated with PTC and the current needs of the manufacturing industry, this is expected to be complete by October, Nambiar both in India and globally. We spoke with Subash said. The main role of Atego would be to integrate Nambiar, Vice President and Country Manager – all the complex products of PTC into a framework to India, PTC, who said this move has naturally made assist in easy working for customers. PTC is aiming the company tread along with current trends and at providing customers with a complete suite of requirements of the industries. tools that will encompass all the requirements of a An example of the changing trends within the manufacturing company. automotive sector, Nambiar said was in the move Another new technology from PTC is one called from complete mechanical parts, to mechanical ‘Unite Technology’ that allows users to import and parts combined with electricals, and finally to soft- export data from multiple CAD environments into ware/ electronics. Therefore, the company’s prod- CREO, which is PTC’s product design software. Unite ucts have also been updated to meet the most technology is unique in a way that various files can trending technologies and their requirements, he not only be imported, but can also be saved into file added. PTC is also increasing its investments in formats of competitor companies. This also allows developing solutions for the manufacturing indus- for the flexibility of consumers to invest in products try, as it sees more business from there. of various companies, and not restrict investments and service smart, connected products. As part of The last time we spoke to PTC, it was investing into PTC. This has helped PTC acquire new custom- PTC, ThingWorx is expected to help customers in a aggressively in its service lifecycle management ers, since they can continue to use other CAD envi- wide range of industries seeking to leverage IoT. (SLM) business, which it claims to continue, with a ronments, and additionally opt for select products Another company acquired by PTC was Atego, focus also on the manufacturing industry. Nambiar from the company, Nambiar noted. which is being integrated with PTC, and is assist- said the SLM, application lifecycle management ing PTC in MBSE, to set up a framework for the in- (ALM) and CAD businesses have performed well, AUTOMOTIVE APPLICATIONS tegration of complex products. It will primarily cater and provide manufacturers with a complete solution to manufacturing industries, and will help in doing in the management of their business. He added that PTC believes that IoT, which is a trending technolo- MBSE models for all the company’s products. PTC is now looking into technologies like the Internet gy, can be put to use in any form of remote monitor- of Things (IoT) and model-based system engineering ing of products. For example, the possible failure, or THE WAY AHEAD (MBSE). Nambiar said PTC is not moving away from end-of-life of a component in any automobile can SLM, but rather adding more products and additions be monitored with the use of such technology. As PTC has a very large number of customers in the to the SLM business division. such, it is highly effective in providing preventive manufacturing segment using PRO E and CAD action or information for a product, before it results products, and the company is contacting them to NEW TECHNOLOGIES ADDRESSED in any kind of failure, Nambiar explained. PTC’s find out their specific requirements. The company technologies can also download software updates has a suite of products, which it wants to educate PTC has grown marginally worldwide, even with the automatically into electronic components that need customers about, and try to advise them on using automotive industry still trying to recover from the updates at regular intervals. Nambiar said a to enhance their business, Nambiar noted. The slowdown it has experienced over the last few years, number of Indian OEMs are already working on company wants to inform clients of the uses of its Nambiar said. The main reason for PTC to invest technologies surrounding IoT. It is expected that IoT various products and the savings that can be and develop technologies and products around IoT is and related technologies will be applied in India on made, either directly or through channel partners. that the competition is also looking at such areas of a large scale within the next five years or so. PTC is also approaching companies using competi- technology. Additionally, the company has also iden- tor products and showing them the advantage of tified a gap in terms of connectivity between the RECENT ACQUISITIONS moving over to PTC’s CREO 3, which allows the in- companies other products. Technologies are improv- tegration of files from other CAD platforms. ing at a fast pace, and the demands of customers PTC has acquired a number of companies in recent PTC expects a good future, especially in India, are also rising, Nambiar noted. times. One of these acquisitions was a company since the company has a complete product offering Nambiar believes that through the development called ThingWorx for the development of products for all types of customers in the manufacturing of IoT, PTC will become a single company to offer related to IoT, which PTC acquired for $ 117 mn. segment. It aims to gain newer customers, as well as complete end-to-end solutions for manufacturing ThingWorx has been integrated with PTC and is part have present customers choosing new products that companies. The other area of interest and focus for of the company’s product portfolio. Nambiar said the the company has developed or added to its portfolio. PTC is MBSE, for which the company recently ac- ThingWorx acquisition extends PTC’s strategy of sup- quired Atego, which is a developer of model-based porting manufacturing companies as they create Text: Naveen Arul

autotechreview October 2014 Volume 3 | Issue 10 5 INTERACTION OMNICOMM

OMNICOMM | OFFERING INDIA-SPECIFIC SOLUTIONS

It is a notable fact that fuel costs account for almost half of the expenses for any business dealing with a large fleet of vehicles. This requires fleet owners to look for systems to manage their fleets and ensure the control of fuel consumption, in order to improve profitability. Various methods can be employed to ensure fuel consumption monitoring, but fuel level sensors are looked upon as one of the most accurate methods of ensuring this. Omnicomm, a Russian company that has been in the market for over 16 years, is a global leader in manufacturing LLS fuel level sensors. The company operates in over 100 countries, and has to its credit installation of 500,000 sensors to date. We met Stanislav Emelianov, Deputy Direc- consider partial manufacturing (assembly opera- to any trackers in the market, which have ana- tor General, Omnicomm (L), and Subramani Sar- tions), as well as a research and development logue, digital or frequency input. There are no pre- avanashekar, Business Head, Asia and ASEAN (R&D) facility in India, he informed. Currently, the scribed requirements for vehicles to be fitted with Countries, Omnicomm (R) on the sidelines of a company carries out R&D from its facility in Omnicomm fuel level sensors, he added. The com- recent industry event. Moscow, with about 40 engineers. pany’s products have characteristics that allow The company plans to bring its entire global them to be installed in any type of vehicle and INDIAN OPERATIONS products portfolio to India, with the expectation of special machinery. its fuel level sensors receiving high demand. In The company said its fuel level sensors can be Omnicomm has been in India since 2007, when it addition, Emelianov added that there is a large installed in fuel tanks that measure 15 cm and worked with partners for the sales and distribu- interest for Omnicomm’s complex fleet manage- more, showing that these sensors can also be in- tion of its products in the country. By the end of ment solutions among fleet owners and industry stalled in many motorcycles. Emelianov said the 2014, the company plans to set-up its first office leaders in the country. company sees good demand from the two-wheeler and warehouse in Chennai, which will also func- Omnicomm recently participated in an indus- sector, adding that Omnicomm is ready to work tion as its headquarters in India. Plans to set-up try event in India, which it used to officially further in that direction. offices in other states of the country in the future launch its products in India. At the same event, has also begun, said Saravanashekar. Technical the company signed four partnership deals with FUTURE EXPECTATIONS specialists and managers working to help coordi- companies including Trans Global Geomatics, nate installations, integrations and provide tech- Pointer India and Leadwinner. Saravanashekar Being a leader in fuel management and fleet nical support for the domestic market will be also said Omnicomm is in talks with a number of management solutions, Omnicomm believes the based in Chennai. companies that are interested in partnering and bulk of sales in India will constitute its fuel level There are no imme- integrating along with the company, to supply sensors. Emelianov said Omnicomm’s fuel level diate plans of fleet management services. sensors have an accuracy rate of 99.2 %, and are setting up a Additionally, Omnicomm is in continuous talks very effective in fuel consumption control. Emeli- manufactur- with OEMs in India, for deals regarding the anov expects a good future for Omnicomm prod- fitment of Omnicomm fuel sensors as original ucts in India, especially since the local telematics equipment in their products. The company also market is rapidly developing. There are a large said that besides new partnerships, Omnicomm number of trucks, light commercial vehicles ing facility in has agreed for integrations with numerous tracker (LCVs), and special machinery for construction India, and the and software manufacturers in India and the US. and mining, which shows there will be demand for company will Omnicomm’s solutions, Emelianov said. He added continue to FUEL LEVEL SENSOR FITMENT that fuel prices are high and seem to be rising import its compo- steadily, making fleet management solutions even nents from Russia, Omnicomm’s fuel level sensors can be fit as after- more necessary. Emelianov said. In market equipment on older commercial vehicles, the future though, as well as on various types of machinery, Sara- the company will vanashekar noted. The sensors can be connected Text: Naveen Arul

6 www.autotechreview.com Event siam

54TH SIAM ANNUAL CONVENTION | CURRENT ENVIRONMENT CONDUCIVE TO GROWTH

The Society of Indian Automobile Manufacturers phase of growth for the automotive sector. (SIAM) recently held its 54th Annual Convention, Vikram Kirloskar, President, SIAM & Vice- with the theme of “Auto Industry – The Engine of Chairman, Toyota Kirloskar Motor, however, added Growth”. The event through its day-long timeline, that sustained growth for the industry will need a stressed at the role the automotive industry will stronger focus on fiscal policies, emissions, play in the country’s economic progress in the safety, competition laws, vehicle technologies and coming years and also discussed ways of further fuel & trade policies. stimulating this growth. Having gone through a recession, the industry BRIGHTER TOMORROW is presently trying to find ways of building momentum and is looking for the government’s con- The prospects of the automotive industry over the tribution as a key ingredient. Supporting this ex- coming years were portrayed to be bright by the pectation, representatives of the government presenters in the event. Already, more than 29 mn assured the continuation of the excise-duty people in the country are employed directly/ indi- rebates along with significant investments in rectly by the automotive industry and in the road transport systems. Nitin Gadkari, Minister, coming years, this number is expected to grow uting 13 % to the national GDP, $ 80 bn + of in- Road Transport and Highways, Government of significantly. Exports was listed as another key vestments and exports reaching $ 40 bn by 2026. India, announced that upto ` 100,000 cr of in- opportunity area for the industry, which presently It’ll be interesting to see how the measures to vestment had been cleared by his ministry for im- stands at over four per cent of the country’s total achieve these lofty numbers are formulated. proving the road network, leading to a sustained exports. This number too is expected to grow sig- Key challenges for fulfilment of the plan growth of the automotive industry. nificantly over the next few years as Indian com- include the lack of a communicative and tech- Along with these announcements, there were panies continue to up their technical competence nology-focussed partnership between the gov- some which focussed on issues such as alterna- in products and production processes. ernment and the industry. If these and many tive fuels, safety and lower emissions. These an- A key discussion point at the event was the more hurdles can be overcome by the stakehold- nouncements, however, did not have any concrete Automotive Mission Plan (AMP) 2026, succeeding ers in the coming years, fulfillment of AMP 2026 numbers and timelines attached to them, making AMP 2016, which is expected to miss its target of might be possible. The intent of the new govern- them primarily a responsibility of the industry. The $ 145 bn revenue and 10 % of national GDP by 25 ment seems conducive to overall growth but overall consensus between the industry and gov- % to 35 %. The new report has some interesting these are early days and actions are yet to speak ernment was that the next five years will be a numbers such as the automotive industry contrib- for themselves.

autotechreview October 2014 Volume 3 | Issue 10 7 Events acma

54TH ACMA ANNUAL SESSION | EYEING THE GLOBAL OPPORTUNITY

the automotive suppliers industry is an irreversi- plier and OEM surveys, the Indian suppliers can ble trend and is likely to increase. This increase look at three key development targets by 2020. will primarily be driven by five macro-trends – This would include increasing the exports contri- globalising OEMs with suppliers following them; bution from the current $ 10 bn to between $ 35 low-cost countries maturing as export hubs; bn and $ 40 bn. The second development is in- platform consolidation and shift towards large crease in revenues from overseas assets from $ 6 global suppliers; increasing aspiration of emerg- bn to somewhere between $ 20 bn and $ 22 bn. ing market suppliers to access new markets and The last aspiration listed in the report is an in- technologies and market diversification for crease of Indian suppliers in the global top 100 margin resiliency. from just one right now to five by 2020. During the event ACMA also announced the WELL POSITIONED appointment of Ramesh Suri as its new President. Suri is the Promoter & Chairman, Subros, and has The report also suggests that Indian suppliers are an experience of over four decades in the automo- well positioned to benefit from these global trends tive industry. On taking up the new responsibility, and can significantly accelerate their internation- he said he is convinced of a revival in the coming al presence in the next few years. The report goes years, leading to better times for the industry. on to say that based on market comparisons, sup- The 54th annual session and conference of the apex body of Indian automotive suppliers, the Automotive Component Manufacturers Associa- tion of India (ACMA), was recently organised in New Delhi, under the theme “Capturing the Global Opportunity”. The aim of the event was to enable suppliers to better explore global opportunities in order to develop a sustainable growth model for the industry. With mild indicators of a recovery visible after a long slowdown, component suppliers are now looking forward to a tide of success. Captur- ing the global opportunity, however, would equate to increase in exports, which according to McKinsey, presently stands at just one per cent of the overall global exports. This figure also highlights the underlying opportunity for Indian automotive component suppliers, who have shown in some areas that Indian technology can be globally competitive. Presenters and delegates at the event seemed convinced of the long-discussed need to invest in technology development, better training and an increased focus on innovation. Most people agreed that the coming years hold good potential for the Indian companies, especially with the positivity surrounding the new government and improving market dynamics. At the event, ACMA-McKinsey launched their joint study titled ‘Capturing the Global Opportu- nity – The Next Imperative for the Indian Auto Component Industry’, in line with the event’s theme. The study highlights that globalisation in

8 www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 9 News MISCELLANEOUS

iCAT | 4TH WORKSHOP ON HEV/EV TECHNOLOGIES HELD

The International Centre for Automotive Technol- ness on the implementation of HEV and EV tech- sessions and panel discussions. It touched upon ogy (iCAT) recently organised its 4th workshop on nology in the Indian market, as well as gaining topics including EV technology and development, Hybrid Electric Vehicles (HEVs) and Electrical Ve- knowledge from the HEV/EV segment. system engineering, powertrain design, battery hicles (EVs) on the topic of opportunities, chal- A large number of speakers from various re- management, energy management, E-motor lenges and technologies in these areas. The search organisations around the world partici- simulation, electrical safety, regulations/ indus- two-day workshop focused on creating aware- pated in the workshop, which included technical try standards and future of hybrids. The National Electric Mobility Mission Plan 2020, which was unveiled in 2013, focuses on building domestic capabilities through R&D and local supply chain for new technologies, iCAT said in a release, adding that the Government of India is also showing interest towards developing a policy to create a national level inter-min- isterial forum to address challenges faced in the HEV/EV industry. This workshop claimed to have laid down a plan for deliberations and discussions, the successful future and implementation of HEVs and EVs in India. It is also said to have put up new ideas and proposals by experts that could be sum- marised as new measures to be taken for the development of future innovations and technologies.

HONEYWELL TURBO | POWERS TATA REVOTRON PETROL ENGINE

Honeywell Turbo Technologies and Tata Motors forward as a global player. already have a strong turbo diesel penetration of worked together in developing India’s first locally Honeywell expects petrol applications to above 50 %, the company said. Honeywell is a developed petrol turbocharged engine, the new drive the rapid adoption of performance enhanc- leader in turbo solutions, and continues to Tata Revotron 1.2T engine, which is seen in the ing turbocharger technologies in India, like in launch an average of 100 new applications every Tata Zest. Honeywell’s second generation petrol Europe. Both Indian and European markets year with about 500 in the development pipeline. turbo technology, which claims to incorporate the latest advances in aerodynamics and bearing systems, is featured in the Revotron 1.2T engine. This turbo technology claims to deliver best-in-class power and torque. Engi- neering teams in Pune and Bangalore are said to have used local capabilities and global expertise in petrol turbo technologies to address the specific needs of Tata. Downsized petrol turbocharged vehicles deliver up to 20 % better fuel-economy and better torque than larger non-turbocharged engines with similar power output, Honeywell said. Turbochargers are also said to help reduce emissions by 20-30 %. Milind Godbole, Manag- ing Director, Honeywell Turbo Technologies, India, said the company is happy to have contributed to the ‘Made in India’ campaign, which is significant for moving the country’s auto industry

10 www.autotechreview.com New Launch | Volkswagen Vento 1.5 TDI DSG MAGNA INTERNATIONAL |

Volkswagen India launched its newly-stylised Vento Highline variants of the Vento. The 1.5 l, TDI tur- INDIA FOOTPRINT sedan, with the highlight being its Vento 1.5 TDI bocharged engine develops 103 hp of power and expanded DSG, which has a starting price of Rs 10.49 lakh, 250 Nm of torque, along with a claimed fuel ef- ex-showroom, Mumbai. The key change in the new ficiency of 21.21 km/l. A detailed review of this Vento range is the inclusion of the seven-speed new engine’s performance is available on page transmission. The 1.5 l TDI engine paired to the 54-55 of this issue. While the 1.2 l TSI and the seven-speed DSG transmission is a first for the 1.61 l MPI engines offer the same amount of Vento family. power, their torque figures are at 175 Nm and The dual-clutch seven-speed transmission 153 Nm, respectively. Magna International, the $ 34.8 bn global auto- will also be available with the 1.6 l MPI engine The New Vento sports other changes in the form motive supplier, has announced further invest- and the 1.2 l TSI engine in Comfortline and of dual front airbags on all variants, re-de- ments in the Indian market by setting up two new signed 15-inch alloy wheels, more power- facilities in the Sanand region of Gujarat. These ful dual-beam headlamps and a flat- new facilities will cater to vehicle programmes bottomed multi-function steering built off global platforms, the company said, wheel. Other changes include Bluetooth without divulging any investment figures. Magna telephony and footwell lights. also recently inked a joint venture (JV) with Tata At the launch, Michael Mayer, AutoComp, to set up a company to deliver innova- Director, Volkswagen Passenger tive seating systems both for trucks and buses to Cars, Volkswagen Group Sales customers in India. India, said that he expects the DSG Of the two plants, one will come up on a variant to do well in the Indian 215,000 sq ft area, and will produce complete market. Asked about the possibility of seat systems for an unnamed automaker. The pairing the 1.2 l TSI motor with a second facility will make body and chassis manual transmission, he said the systems for multiple customers in a 356,000 sq ft same is technically possible but the plant. Both plants are expected to start volume company has no concrete plans of production in 2015, and will employ 200 and 400 doing so. people respectively, the company said. The JV company between Magna and Tata AutoComp will be situated in Pune. For Magna Seating, leveraging its expertise in automotive seating and delivering it to the Indian CV New Technology | Bosch develops Adaptive market is an important part of its global growth strategy, said Deepak Nagaraja, Vice President, Cruise Control System Magna Seating. Bosch has developed a new adaptive cruise permanently monitors the road ahead. Once a Magna currently has two existing body and control (ACC), which adjusts the vehicle’s driving slower car is spotted within its detection range, chassis plants, one in Pune and the other in speed to the flow of traffic by automatically ac- the system gently reduces speed by releasing the Chennai, both catering to stamping, welding and celerating and braking when activated. Bosch accelerator or actively engaging the brake control assembly requirements different OEMs. It has a ACC is claimed to maintain a pre-set safe dis- system. The ACC automatically accelerates to the plant in Bangalore that makes vacuum pumps, tance to the vehicle in front, allowing the driver driver’s desired speed once the vehicle ahead and also houses a seating design and engineering to concentrate on the driving situation at hand, changes lanes or speeds up. centre in Pune. Additionally, for R&D, Magna has in heavy traffic situations. a body and chassis engineering centre in Banga- Bosch’s standard ACC can be activated from lore, seating and full-vehicle engineering centres speeds of about 30 km/h, with the Stop & Go in Pune and a latch and closure engineering version, being able to be activated even below centre in Chennai. 30 km/h, the company said. In case of automatic The Indian market offers tremendous growth transmissions, ACC Stop & Go can set the opportunities for Magna, and the current expan- vehicle in motion after a brief halt. Both versions sion is targeted at reaching overall India sales ensure smooth, fuel-efficient, and safe driving revenue of $ 300 mn by 2016. That would reflect a of the vehicle. growth of over six times since 2013. In India, the The core of Bosch ACC is the radar sensor, company is building positions in metal forming, which is installed at the front of the vehicle, and seating, closures and powertrain areas.

autotechreview October 2014 Volume 3 | Issue 10 11 Guest commentary

RAJEEV SINGH is Partner and Head of Automobile Sector, KPMG in India

DRIVERLESS CARS: TRULY ‘AUTO’MOBILE

For nearly 125 years the automotive industry has been a force for TRENDING TOPICS innovation and economic growth. Now, in the early decades of the 21st century, the pace of innovation is speeding up and the The terms ‘autonomous car’ and ‘driverless car’ have picked up industry is on the brink of a new technological revolution: ‘driv- 30-fold interest in internet discussions over the past 10 years. erless’ cars. These self-driving vehicles present a potential of be- Opinion volume began to spike in July 2013 driven by UK’s an- coming a viable form of transport in the future. nouncement that self-driving cars were approved for testing and several automakers’ announcements of launching a self-driving vehicle by 2020. India ranks second in searches for these terms, THE REVOLUTION just after the United States. This is primarily on account of a lot of developmental work being conducted by Indian researchers based A driverless car, also called a robotic car or an autonomous car, out of the development centres in Bengaluru and Hyderabad. is a vehicle capable of sensing its environment and navigating without human inputs. Major luxury car manufacturers, leading technology firms and research organisations have developed THE INDIAN EXPEDITION working prototype autonomous vehicles and are adding self-driving technology to their current range of vehicles. In recent devel- Luxury cars in India are available with advanced driver assist opments, two luxury carmakers have received newly required li- features such as Adaptive Cruise Control and Active Parking. Al- censes from California to conduct tests in daily traffic. though leading Indian automotive firms are fostering develop- Over the last decade, leading technology firms have an- ment of innovative solutions for driverless cars in India, low data nounced the launch of their driverless car projects. Their technol- coverage and connectivity are hampering the development of a ogy uses LIDAR, which works like a radar and sonar but is far connected car environment. Telecom service providers are also more accurate. It maps points in space using rotating laser beams joining hands with automotive companies to enable creation of that take more than a million measurements per second to create the connected car environment with V2V technology. an accurate 3D image of the surroundings. It is quite likely that the technology of driverless cars will be Given the pace of technological advancements, automobile made available to the Indian customers around the same time as companies engaged in the development and auto industry ex- the global market. The question is whether the Indian consumer perts now believe that the driverless car will become commer- is ready to cruise along at steady speeds in a driverless car. To cially available and viable by 2025. answer that question, let us first look at the advantages of a driv-

12 www.autotechreview.com erless personal mobility environment in India. Automakers and insurers are already working on preventing :: Better personal productivity: On an average, Indians spend 1.5 intruders from gaining unauthorised access to information or hr in daily commute behind the steering wheel. As much as hijacking vehicles by remote control. 8-10 % of the time is spent in searching for parking, which :: Achieving the network effect would be critical for the success could become available, when the self-driving car drives off to of the autonomous system. It would require a large number of park itself. vehicles to be equipped with interoperable communication :: Better on-road safety: Based on national statistics of road traf- systems and cooperation. Retrofitting the “driverless car” sys- fic accidents in India published by the Transport Research tem on the large number of vehicles already on the road Wing of the Ministry of Road Transport & Highways, fatalities would be made possible using economically viable technol- in road accidents, in 2011, were as high as 2.43 lakh. Out of ogy. The network effect would be essential to bring down the every 100,000 vehicles, 212 vehicles on the road are involved cost of advanced sensing and imaging equipment, which in road accidents. The incidence of traffic accidents is rising by would be fitted on the roof of every car. 8-10 % every year owing to the increase in the number of vehi- :: Licensing and operation of autonomous vehicles will have to cles on Indian roads. And research shows that 94 % of traffic be permitted by the state and national laws to enable compa- accidents are caused due to human errors. The economic nies to test their technology. The central and state legislations impact of crashes in terms of the medical expenses, repair will require a cohesive and uniform approach on this front. expenses, congestion costs and legal expenses is significant. In The government, automobile associates and research insti- this developmental journey, the purpose would be not just to tutes will have to work together to create the specifications for make safe self-driving cars but to develop ‘crash-less’ cars. autonomous vehicles. And these will need periodic review :: More efficient cars: Self-driving cars will operate in cruise con- and enhancement as the technology evolves further. trol mode, which can help ensure better fuel efficiency and :: The technology is ahead of the law in many areas. A legal lesser pollution. Self-driving cars can also be used more effi- framework will be required to deal with the complex liability ciently throughout the day instead of being parked for 20 issues that may arise, such as who will be held responsible in hours every day. case of an accident – the car-owner is not driving the car and :: Better usage of available road capacity: Today’s roads have to car-maker has nothing to do with the everyday running of the be designed to cater to imprecise and unpredictable move- car. The critical question of ‘who owns the risk’ will need to ment patterns of human-driven vehicles. In an autonomous be addressed before the autonomous system gains acceptance vehicle environment, efficiency can improve so dramatically from masses. This could be an uphill task in India given the that traffic capacity can improve without building additional population and diversity of cultural and social patterns. lanes or roadways. Self-driving vehicles could have the ability to ‘platoon’, in dedicated lanes, which can support high traffic density without compromising on the speed, and thus can be BON VOYAGE a very efficient system. :: An enormous amount of data would be available for analytics Consumers seem to be open and interested in the possibilities of and aggregation, which could provide a potential for increas- self-driving vehicles and see an appealing value proposition. In- ing vehicular and passenger safety. Data could also be used dustry and technology is moving very fast to develop and fine- by state transportation departments for creating and maintain- tune the technology to support a variety of driving conditions. In ing safe driving conditions. the coming years, we are likely to see many more prototypes getting launched and advanced technologies getting tested for providing a safe and efficient mobility solution. Governments would ROAD UNDER CONSTRUCTION need to move equally fast and decisively on creating the appropriate legislative framework. Some of the important questions An autonomous vehicle environment in India would bring with it that remain to be answered are pertaining to the creation of a many challenges – technological, cultural, and vehicle infrastruc- business model for the huge investment required for infrastruc- tural. At the same time there is a new perspective required for ture, the legal and economic model for product liability and in- creating the appropriate legislative framework. surance, and the framework for data security. :: The technology would need to cater to the difficult condition of roads, potholes, flooded roads & pedestrians, cyclists & ani- (With inputs from Nikhil Pingle, Associate Director, KPMG in mals sharing the road with cars. The technology will also India) need to be tweaked to assess the driving patterns of human- driven vehicles and traffic discipline, or the lack of it. “The views and opinions herein are those of the authors and do :: The enormous amount of data could present challenges of not necessarily represent the views and opinions of KPMG in In- data security, privacy, ethics and policy dilemma. The system dia. All information provided is of a general nature and is not in- will need to be robust to prevent any security threats arising tended to address the circumstances of any particular individual out of hacking or altering records. Technology will need to or entity.” enable people in the vehicle to control the amount of data available to the outside world. Passengers could be provided Read the full article on with the option of erasing data after they have left the vehicle. www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 13 interview TATA MOTORS

“2015-16 COULD SEE RECOVERY OF THE INDIAN AUTOMOTIVE INDUSTRY”

The commercial vehicle sector is generally a good indicator of a country’s economic progress and it isn’t unknown that both of them haven’t been in the best of their shapes in the past few years. Tata Motors, the largest CV maker in the country has gone through a long and dramatic downturn in this phase, but SIAM data from the past few months does show a trend reversal. In order to understand if this blip is a sign of actual recovery and to understand how Tata Motors is placed in these times, we caught up with Ravindra Pisharody, Executive Director, CV Business Unit, Tata Motors.

Ravindra Pisharody has work experience of over 30 years, and- Director for the regions comprising India, Middle-East, Africa has been serving as the Executive Director, Commercial Vehi- and Turkey, and was subsequently based in Singapore in a cles, Tata Motors since June 21, 2012. Prior to this, he was the global marketing role. Before Castrol, he worked with Philips Vice-President, Commercial Vehicles, Sales & Marketingsince India from 1981 to 1999, a subsidiary of the Dutch company 2007, when he joined Tata Motors. He also serves on the board and served as its Vice President of the Consumer Electronics of various Tata Motors group companies. Prior to joining Tata Division. Pisharody holds a Bachelor of Technology degree in Motors, he was associated with Castrol Ltd, a subsidiary of BP, Electronics Engineering from IIT, Kharagpur and is also an where he worked from 1999 to 2007, as the Regional Marketing alumnus of IIM, Kolkata.

14 www.autotechreview.com ATR_Coming from a severe downturn, truck range. The Prima LX, for example, Within the multi-axle segment, the largest especially for the commercial vehicle (CV) was developed based on customer feed- contributor is the three-axle sub-segment, sector, how is Tata Motors placed pres- back as they liked the Prima’s quality where the Prima LX has been positioned. ently and how prepared is it for the cabin, powerful powertrain and lesser In order to keep costs low and not sacri- future? turnaround time but wanted a more fice upon the qualities of the Prima range, Ravi Pisharody_Going by the numbers, affordable version of it. Hence, we built we had to develop a new engine in collab- we’ve been posting in the recent months, the Prima LX on a 230 hp powertrain oration with Cummins through our Tata there seems to be some signs of recovery instead of the 280 hp available on the Cummins joint venture. The key require- in the medium & heavy CV (MHCV)seg- Prima. In addition, we’ve retained the ment for this engine, called the ISB 5.9 l, ment, which is 16 tonne and above. This basic features of the Prima cabin and its was to be developed in accordance with segment is always seen to be a lead indi- frame, including key safety features. Indian requirements, in order to make the cator of upcoming trends. It was the first We’ve introduced six new tippers in the truck competitive in the market. one to start receding nine quarters ago Prima LX range in the 25 to 31 tonne seg- The Ultra truckwill cater to the seven and for the downturn to hit the passenger ment, with engines developing 230 to 280 to nine tonne segment, of which the eight vehicle segment and smaller CVs. After a hp. Six new additions have been made to and nine tonne vehicles are already in the decline of about two years, we can clearly the Prima LX tractor range as well. Going market and a 10 tonne variant will be see an upward trend now. Particularly in forward, we’ll soon launch two new Prima launched in October 2014. Based on our the last few months, growth has been in multi-axle trucks, which are going to be a benchmarking, we consider the Ultra to double digits. Going forward, with the first for the Prima range. The MHCV be the best-in-class in terms of features, excise duty extension, this year will not industry sees about 60 % of its sales com- technology and comfort in the country. be a year of decline for MHCVs. ing from multi-axle trucks, forming good potential for the two new models. Tata has been actively working on modular Do you have any numbers to share? In addition, beyond trucks, we’ve platforms. Any new developments herein? It’d be hard to predict the rate of growth as taken some initiatives to improve the run- We have been working on modular plat- important markets of Jammu & Kashmir ning experience for customers, including forms in the CV space since a long time, and North-East have been hit by floods. the increase in warranty from two years to even before the Prima was launched. All Due to the effect of these natural calami- four years and 400,000 km on the drive- our multi-axle trucks are on a single plat- ties and various other factors, it’s hard to line. Such warranty offering is unheard of form and continue to cater to various put a number to the growth right now. in the Indian CV industry and in many categories, highlighting the platform’s On the side of the light commercial international markets as well. We’ve also flexibility. The Prima platform itself is vehicles, there are still issues such as increased our service intervals signifi- flexible enough to accommodate engines financing. Due to the ongoing downturn, cantly along with some other aggregates, upto 560 hp, so with 230 hp and 280 hp many customers have defaulted on their all of which will lead to an overall better we’re barely scratching the surface. Add payments, which have now made it diffi- experience for our customers. to this a wide range of transmissions and cult for them to avail finance for new options for other components and our vehicles. The loan values too have gone Help us understand the technical platforms turn out to be truly flexible down to 80-85 % of vehicle cost, opposed nuances behind developing the Prima and modular. It is imperative to work on to the 90-95 % given earlier. So, while an LX and the Ultra. modular platforms in the CV space, immediate recovery isn’t around, if the MHCV segment continues to grow, a full recovery could be expected to begin from sometime in 2015-16.

Tell us about your new product strategy. We’ve been following an aggressive product strategy in the past, due to which we’re well positioned to benefit from the turnaround, whenever it happens. A recent and important product is the Prima LX, which offers the key features of the Prima at a much more competitive price.

Are there new segments you’re planning to enter? We are but it may not be right for me to talk about them at this stage. What I can tell you is that we’ve made significant progress in the last six months in our 60 % of the MHCV sales come from multi-axle trucks, where we’ve placed two new models autotechreview October 2014 Volume 3 | Issue 10 15 interview TATA MOTORS

These are not the transporters, but steel and petroleum companies, for instance. Together, we study the inbound and out- bound logistics and take note of the challenges faced by them and make changes to the vehicles accordingly. We also offer a fully-built range of tractor trailers for move- ment of goods such as steel and cement. In terms of numbers, I can’t update you of the same since we do not look at this division solely as a revenue contributor but more from an industry-mover perspective. We’ve earlier brought new concepts into the country such as the bulker, which is now being manufactured by different companies.We’re fine with that as it has helped the overall industry to become more efficient. We’ve spent between ` 1,300 & 1,500 cr on product development this fiscal What work is being done in the space of alternate fuels? which we have been doing and will con- What is the company doing in the intelli- Tata Motor has showcased a range of tinue to do in the future. gent transport system and related space? commercial vehicles under its FuelNext The recent announcement between us theme, focused on contributing to cleaner, There’s a lot of action in the weight-reduc- and Microlise for advanced telematics and greener, efficient and comfortable trans- tion space these days across the automo- fleet management services is a step in the port solutions. Some of these include the tive industry. What’s new from Tata Motors same direction. What we’ve launched for Magic Iris Electric, a clean and eco- on its CVs? now is just the GPS-related services, but friendly passenger commercial vehicle Lightweighting in CVs needs to be done the potential ranges right upto trucks with a segment first solar charger. We also keeping in mind the operating economics being connected with multiple aggregates showcased the Starbus Urban FE-Parallel- of the end customer. With increasing pay- communicating with our central system. Hybrid Buses, which lower emissions, loads, if the engine size keeps going up, Beyond this the government is also reduce running costs and improveeffi- the monetary results might not be pleas- working on ITS in the state buses and the ciency. The front-engined, clean fuel bus ing for the customer. We try and light- second lot of buses under the JNNURM also provides ease in urban transporta- weight our vehicles in various areas, scheme already have a fair amount of ITS tion. The Starbus Urban 9/18 FE is an including an aluminium housing used requirements specified, all of which is articulated bus with a single deck and two instead of iron around the gearboxes, being met by us. In general, ITS is an sections enabling to carry more passen- some of which have already been con- extremely broad subject and depends on gers, while retaining the manoeuvrability verted. We also have aluminium housing the evolution of the entire ecosystem. As needed in urban transportation. In addi- for engines for some of our passenger demands grow, we can get into partner- tion, we have the Prima 4032.S LNG as a cars, which we are looking at leveraging ships like the one with Microlise and lev- green alternative to diesel and is also a for CVs as well. erage the technology instead of reinvent- superior fuel compared to CNG, thus On the suspension front, we’ve ing the wheel. ensuring better fuel economy. replaced the bell crank suspension with bogey suspension, which is not only Can you tell us the amount of money The truck racing initiative was received lighter but is stronger as well. The next spent on product development this year well. Can we expect any technical pro- step for us herein is to use more of rubber for CVs? gress in its next edition? in suspension parts, which will not affect The figure would sit between ` 1,300 and Tata Motors received an overwhelming the operating capabilities such as load- ` 1,500 cr for this year on overall product response at India’s first truck racing carrying capacity but has the potential of development activities. event, the T1 Prima Truck Racing Cham- reducing upto 300 kg on a heavy truck. pionship. We will make announcements Plastic can also be used to replace metal How does the application business look related to all aspects around our next in fuel tanks and propeller shafts. for you? truck racing initiative shortly. We’ve identified a few lead applications, Are you using plastic fuel tanks currently? including coal, cement, steel, petroleum Not yet, but we’re working on the tech- and automotive logistics, among others. nology and are exploring the opportunity These are the segments, where we work in Interview: Arpit Mahendra to implement it. tandem with the consigner companies. Photo: TATA

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TRENDS IN LIGHTWEIGHTING OF BEVs: A REVIEW OF STRATEGIES – Part II

Electric vehicle (EV) is not just a change in fuel, or energy source. It is a new paradigm in mobility and hence it brings with it possibilities of disruptive innovations in the way a vehicle, or even the transportation system, is designed. The future lightweight EVs, thus, may adopt lightweighting strategies that not only covers innovations in materials, design and joining technologies, but also in the form of new approaches towards systems integration, drivetrain configurations, packaging, and thermal management, et cetera. This the second of the two-part article on lightweighting trends of BEVs.

18 www.autotechreview.com autHors LIGHTWEIGHT BODY AND COMPONENT DESIGN

Traditional approaches towards lightweighting of vehicles include use of lightweight materials (both for structure, closure panels as well as powertrain compo- SURESH BABU MUTTANA nents), structural design, and joining is Scientist C at TIFAC, Department technologies. For EVs, new concepts like of Science & Technology, Government of India. use of body panel for energy storage are being explored. Use of Lightweight Materials: Significant work has been reported on reducing vehicle mass, wherein conventional steel is replaced with lightweight materials such as advanced high strength RAKESH KUMAR DEY steels (15-25 %), aluminium (40-60 %), is Project Associate at TIFAC, carbon fibre (50-60 %) and magnesium Department of Science & (60-75 %). Body-in-White (BIW), closure Technology, Government of India. panels and powertrain components have been developed using these lightweight materials, while monocoque frame, space frame and multi-material designs, 1, have also been explored. Such efforts help in developing lightweight and energy effi-

ARGHYA SARDAR cient vehicles. is Scientist E & Head, Transportation Use of Body Panels for Energy Storage: Division at TIFAC, Department of What if the body panels of the car itself Science & Technology, Government of India. are made as a battery? Carbon fibre is a suitable material for this purpose, as it can fulfil two functions in an electric car – as a lightweight composite reinforcement material for the car’s body, and as an active electrode in lithium-ion batteries. The idea is to develop a structural battery consisting of multifunctional lightweight materials that simultaneously manage mechanical loads, and store electrical energy. This can result in a weight reduction for EVs. A project by British researchers and Volvo Cars used multi-layer carbon fibre body panels that store electricity, serving as a battery or as a capacitor. A material composed of carbon fibre, nano-struc- tured batteries and super-capacitors, creating a sandwich of materials that can take on the shape of body panels of a car and store and charge energy, was used. The material can be moulded and formed to fit around the car’s frame in locations such as door panels, trunk lid and wheel bowl, substantially saving on space. The skin of the vehicle would essentially act as one large thin, lightweight battery. A carbon fibre-based composite forms the electrodes in the novel energy storage units. Carbon fibres are coated with car- autotechreview October 2014 Volume 3 | Issue 10 19 Technology foresight LIGHTWEIGHTING

1 Citroën C4 Cactus AIRFLOW 2L concept to be unveiled at the Paris Motor Show uses multi-materials

bon nanotubes (CNT), where additionally Graphene is a material made from a single for reducing the emission of smoke), incorporated lithium atoms increase con- layer of carbon atoms, which is stronger and superior durability, 3. ductivity. The composite of carbon fibres than diamond, is lightweight and is flexi- The University of Sunderland, work- and CNTs is embedded in a polymer resin ble. This ‘wonder material’ has the poten- ing with a consortium of five research and glass fibre mats between the energy- tial to stimulate more sustainable trans- partners from Italy, Spain and Germany, saving layers serve as insulation. This port with light and ultra-efficient batteries under iGCAuto proposal, have been allows the materials to be used as and can be used in ultra-capacitors, solar investigating to understand and analyse super-capacitors. cells and as lightweight materials for vehi- the properties of graphene to determine Components in the Volvo S80, such as cle body applications. how it behaves, when it is used to the trunk lid were developed using the Graphene has tremendous applica- enhance the advanced composite mate- above materials. Structural super-capaci- tions for the automotive industry and rials used in the production of cars. A tor laminates are integrated on the outer using it to enhance the composite mate- novel graphene based in the fabrication skin of the trunk lid. The material was rials in cars has large potential. Gra- of nano-composites with different poly- recharged and energised by the use of phene, providing unprecedented mer matrices will be investigated, mod- brake energy regeneration in the car or by mechanical characteristics, could offer elled, and designed to enhance both plugging into the electrical grid. It then the desired solution. This material will vehicle and occupant safety; yet remain transfers energy to the electric motor, provide benefits such as improved very light. The challenge here is not which is discharged as it is used around strength, dimensional stability and bet- only producing graphene-based prod- the car. The research results showed that ter thermal behaviour, better flame ucts, but also applying them on a large- this material charges and stores energy behaviour (active as flame retardant and scale in cars [6]. faster than conventional batteries can. It is also strong and flexible. This work is The latest nanomaterials made of extremely being accompanied by development of an thin and strong carbon fibre replaces the car’s steel body panels and can be used in electrically conductive epoxy resin for the car’s roof, doors, bonet and floor, These panels also double up as the car’s battery. fibre-reinforced composites [4]. Volvo suggests that the complete sub- stitution of an electric car’s existing components with the new material could cut Expected range is the overall weight by more than 15 %, 2. 130 km when the doors, roof and This is not only cost-effective but would bonnet are replaced. -15% also have improved impact on the envi- The car’s weight can be ronment [4]. If future composite battery reduced by 15%. There is potential for cutting weight 130 km structures could store energy as efficiently still further. Electrons (•) as lithium-ion batteries, an EV would The body panels are require only the roof, hood and trunk lid Carbon fibre discharged as Ions (+) Fibreglass the car’s to be made of such materials to achieve electric motor The material can be recharged by Carbon Fibre an 80 ml (approximately 130 km) range. 1) harnessing the energy generated is used. when the car brakes Use of Graphene-Based Materials for 2) plugging into the mains electricity grid Structural Applications: 2 Volvo's illustration of the benefits of using new materials

20 www.autotechreview.com Lightweight Graphene-based WIRING HARNESSES AND materials for structural applications IN-VEHICLE NETWORKS

A large number of wiring harnesses are Graphene nanocomposites Nanostructured TE materials used in EVs to supply electricity and elec- for integrated sensors (cooling/heat recovery) trical/ electronic signals. Various func- Nanofluids tions in a conventional vehicle like engine Functional textile (friction/thermal management) management, power steering, windows control, wipers, air-conditioner, and light- Sensors for pollutants detection ing can be performed by electronic control and safety Smart adhesives units (ECUs), which vary in numbers in 3 Appplication of graphene in a car different type of vehicles. For example, there are two ECUs in the Tata Nano, and more than 100 in a Mer- high voltage cable length and supporting tery recharge system based on an Induc- cedes S Class car. Today, data communi- structure. The goal is to increase the peak tion Motor. The technique is to use the cation between ECUs is accomplished power density (kW/l) and peak specific motor as a set of inductors during charg- mostly by sending communication signals power (kW/kg). ing time to constitute a boost converter over dedicated wires, although network Weight and volume reduction of with the inverter to have unity power fac- protocols like CAN, LIN and FlexRay are power electronics components must be tor operation. With the use of inexpensive also used in a limited manner, mainly in done without affecting the efficiency, relays, the machine windings are reconfig- high-end vehicles. and at the same time, safety standards ured to be inductors in the charging time. In a midsize car, average weight of a must be maintained or enhanced. Differ- Thermal management system for wiring harness is about 45 kg. In an EV, ent components, which mainly contrib- power electronics in EVs add significant there are more number of ECUs for over- ute in weight and volume in power elec- amount of additional weight. This can be all vehicle management, battery control, tronics system of xEVs, include: (a) reduced, if the cooling requirement is less motor control, and other functions like outer case/ housing; (b) cooling system; stringent. Wide Band Gap (WBG) semi- brake, lighting, et cetera. Moreover, (c) inductors; (d) capacitors; (e) resistor conductor devices are able to operate at demand for electronics is increasing in and (f) high voltage cabling, switches, higher temperatures as compared to con- modern vehicles, for various functions sensors, etc. ventional silicon-based semiconductors. like navigation, intelligent transportation The on-board charger and the bi- Thus, use of WBG semiconductor devices system, and cruise control. This means directional DC/DC converter consist of can play a significant role in reducing the the complexity of wiring harness would similar kind of hardware, and hence can complexity of the cooling system and increase over a period of time. share the same power stage, as charging making them lightweight and compact. Use of in-vehicle network protocols and propelling do not happen at the Similarly, enhancing temperature with- like CAN, LIN and FlexRay can help in same time. It is possible to integrate standing capability of capacitors is also reducing wiring harnesses. These proto- them in the EV. required for simplification of the cooling cols have varied levels of utilities, since Another method of integration is to system. A solution to this problem is to cost, data transfer rate and bandwidth, use electric motor winding as inductors in develop a new ceramic capacitor dielectric among other factors, are different. LIN is the charging circuit. Weight reduction can material with high energy density, which least costly but has limitations. Both be achieved as high current inductors are operates with a stable capacitance at tem- CAN and LIN are comparatively slow (1 large components compared to other com- peratures of 200 °C and above. Mbps and 20 Kbps) as compared to ponents. This method helps in elimination FlexRay (10 Mbps). For future vehicles of separate inductor core used for power with intensive electronic contents, Ether- factor correction in charging mode. DRIVE-BY-WIRE METHOD net (100 Mbps) communication protocol In one another approach, integration is is also being explored. done by a combined motor drive and bat- Instead of using mechanical cables,

COMPACT AND LIGHTWEIGHT Weight of Power Convertor POWER ELECTRONICS Vehicle Model unit (PCU) & Inverter Volume of the unit assemblies

An EV needs various power electronics Nissan Leaf 2012 16.2 kg 15.6 L and electronic systems like inverter, bi- Toyota Prius 2010 13.0 kg 16.2 L directional DC/DC converter, on-board charger and ECUs, among others, 4 [7]. Toyota Camry 2007 17.4 kg 11.7 L Innovative integration techniques can Hyundai Sonata 2011 12.3 kg 10.6 L help to reduce the number of power switches, diodes, additional heat sinks, 4 Weight and volume of electric power units in various vehicles autotechreview October 2014 Volume 3 | Issue 10 21 Technology foresight LIGHTWEIGHTING

optimal multi-materials solution, and also multi-faceted utilities of innovative materials such as Graphene. EVs may also bring changes in the automotive supply chain. Traditionally, vehicle manufacturers produced engines in-house. However, key components of the electric drivetrain, like the motor for instance, may be more amenable to standardisation. In such a context, one of the possible scenarios could be reduction in the manufacturing intensity of the OEMs, with their role as systems integrators being enhanced. They may lose a major part of the value creation to the electric drive suppliers. According to a market study, the manufacturing depth of vehicle manufacturers in the powertrain segment will decline from 51 to 31 % for hybrid cars, 5 General Motors' Hy-Wire Concept showcased in 2003 and down to 0 % for electric cars.

References hydraulic pressure and other things that EVs, a high voltage battery pack is already [1] Florian Klug; How Electric Car Manufacturing Transforms Automotive Supply Chains; Munich provide the driver with control over the available to power the controller, actua- University of Applied Sciences, Germany. speed or direction of a vehicle, drive-by- tors and sensors. An EV is driven by a [2] X D Xue, K.W.E.Cheng and N C Cheung, Selec- wire technology uses electronic controls traction motor, so drive controller can be tion of Electric Motor Drives for Electric Vehicles’, to activate brakes, control the steering, integrated with drive-by-wire electronics Australian Universities Power Engineering Confer- ence (AUPEC’08). and speed of the vehicle. The drive-by- control, and during stopping or de-accel- [3] Muttana, S. B and Sardar, A., "Lightweighting wire is further divided into many sub cat- erating, regenerative braking can also be of Battery Electric Cars: An Impact Analysis Using egory like throttle-by-wire, brake-by-wire, applied easily. It also provides good Indian Driving Cycle," SAE Technical Paper 2013- 01-2831, 2013, doi:10.4271/2013-01-2831. shift-by-wire, steer-by-wire, park-by-wire amount of weight reduction. [4] http://www.greencarcongress. etc. Since many traditional components com/2013/10/20131017-volvo.html such as the steering column, intermediate [5] Gubther Schuh, Kai Korthal, Jens Arnoscht, ‘Contribution of body lightweight design to the en- shafts, pumps, hoses, belts, coolers and CONCLUSION vironmental impact of electric vehicles, Advanced vacuum servos and master cylinders are Materials Research, Vol. 907 (2014) pp 329-347 eliminated from the vehicle, it results into Although for OEMs at present, conversion [6] http://www.sunderland.ac.uk/newsevents/news/ significant weight reduction. design may be a more feasible option, news/index.php?nid=2810 [7] Tim Burres, Oak Ridge National Laboratory; There are various examples of drive- with higher penetration of EVs, purpose Benchmarking State-of-the-Art Technologies; 2013 by-wire technology being implemented in design is expected to gain importance. DoE Hydrogen and Fuel Cells Program and Vehicle IC-engine vehicles. General Motors dem- That will bring out the true potential of Technologies Program Annual Merit Review and Peer Evaluation Meeting onstrated a drive-by-wire system in 2003 electric mobility. It is crucial to under- with its Hy-Wire concept, and Mazda stand the definition of design methodol- Ryuga concept also used this technology ogy in order to develop general design in 2007, 5. Electronic throttle control is guidelines and testing procedures towards more commonly used as compared to oth- more sustainable, lightweight, modular ers, and a number of vehicles have concepts of the design process. For this already started using this technology. purpose, it is required to evaluate the Read this article on Brake-by-wire can also be found in pro- architectural configurations for future EV, www.autotechreview.com duction models, and two examples of the technology are Toyota’s Electronic Con- trolled Brake and Mercedes Benz’s Senso- Technology Information, Forecasting and Assessment Council (TIFAC) is an auto tronic. Infinity 2014 model Q50 sedan fea- nomous organisation set up in 1988 under the Department of Science & Technology to ture steer-by-wire technology. look ahead in technologies, assess the technology trajectories, and support technology A main challenge for wide implemen- innovation by network actions in select technology areas of national importance. tation of drive-by-wire technology in IC- engine vehicles has been the need for a Send in your feedback to [email protected] high voltage system, and higher cost. In

22 www.autotechreview.com

Cover Story PISTONS & RINGS SYSTEM COMPARISON OF steel & ALUMINIUM PISTONS FOR PC DIESEL ENGINES

In recent years, the steel piston has proven to be significantly superior to its aluminium counterpart under the special operating conditions of commercial vehicle engines. The greater strength of steel, in particular, is a primary factor due to the prevalence of high mechanical loads. Recently, it has been increasingly considered whether the use of steel pistons would also be advantageous in passenger car diesel engines. Mahle investigated this topic through a system comparison in a turbocharged diesel engine.

24 www.autotechreview.com Authors

DR. SIMON SCHNEIDER DIPL.-ING KAI SCHREER DIPL.-ING. HOLGER EHNIS DR. STEFAN SPANGENBERG is Project Manager Corporate is Project Manager Pre-Development is Development Engineer is Director Product Development Advanced Engineering for PC Diesel HSD steel Pistons at Mahle GmbH in the Engine Test Laboratory at Engine systems and Components Technology at Mahle International in Stuttgart (Germany). Mahle International GmbH in Europe at Mahle GmbH in GmbH in Stuttgart (Germany). Stuttgart (Germany). Stuttgart (Germany).

STATE OF THE ART steel piston concept. The reduced oscillat- furthermore allows the installation clear- ing masses may make it possible to elimi- ance to be tight, while maintaining suffi- The aluminium piston is currently the nate the balance shafts. cient operating clearance, when the pis- state of the art for passenger car (PC) die- The steel piston also allows the cooling ton is hot. Since frictional losses can be sel engines. Steel pistons are under devel- gallery to be positioned higher [5], thus avoided with low piston overlap, this opment [1] and are close to start of produc- reducing the top land height. In both provides an advantage especially under tion. In order to directly compare the cases, a reduction in compression height high loads. behaviour of the two piston concepts in a becomes possible. The reduced compres- passenger car application, Mahle per- sion height can be used to extend the formed a system comparison of steel and length of the conrod in an existing engine OPERATING BEHAVIOUR aluminium pistons in a turbocharged die- concept, for example, while keeping the sel engine [2]. The investigation targeted swept volume the same. This reduces the The pistons compared in this study are the frictional and thermodynamic differ- maximum lateral forces and therefore the developed to the point of series produc- ences between the two while maintaining friction forces on the piston skirt. It is tion and their clearance is optimised for emissions values. also possible, however, to take advantage each concept. Both feature a DLC-coated For this purpose, an aluminium piston of the reduction in compression height piston pin of the same diameter and the with cooled ring carrier was compared by adjusting the displacement of the same ring pack optimised for frictional with a so-called TopWeld steel piston. The engine (rightsizing) and the combustion loss. The operating values of the pistons friction was measured using the indicat- chamber geometry. For a new develop- are compared in the operating map for ing method [3], the piston temperatures ment of an engine series, the reduced identical nitrogen oxide emissions were captured online during operation [4], compression height can directly reduce (achieved by adjusting the EGR rate) and and a thermodynamic assessment and the overall height of the engine, thus identical 50 % heat release points. For exhaust gas analysis were performed. decreasing the installation space full-load operation, the comparison is required. This can have a positive effect made only for identical 50 % heat

on the cw value and pedestrian protection release points. COMPARISON OF THE STEEL AND for the vehicle as a whole. 2 shows the difference in friction for ALUMINIUM PISTON DESIGNS The lower thermal expansion of steel the two variants in the operating map of

As a material, steel is characterised by the following properties as compared with Wall thickness Wall thickness aluminium: at piston bowl at piston bowl :: Reduced thermal expansion, Top land Top land :: Increased strength, :: Greater density, and :: Reduced thermal conductivity. Cooling channel

These properties must be taken into con- Compression height Cooling channel sideration and exploited when implement- Compression height ing a design for a steel piston concept, which is the only way that they can contribute to reducing CO2 or to improving engine performance. For the steel piston, the wall thickness can be reduced greatly AB due to its higher strength, 1. Conse- quently, the weight of the piston group ❶ Comparison of the geometry of the steel piston (A: TopWeld) and the aluminium piston (B: piston with can be the same or even lower with a cooled ring carrier) autotechreview October 2014 Volume 3 | Issue 10 25 Cover Story PISTONS & RINGS

❷ Friction difference in the operating map, shown as the difference in friction mean effective pressure (FMEP) over indicated mean effective pressure (IMEP) and engine speed (positive values: steel piston has lower friction) (full load points (1 to 9) examples with increasing speed of the full load curve, mapping points 1 to 7 as a representative selection for a “normal operation”)

the test engine. The steel piston has a fric- thermodynamics and the oil pump drive remained acoustically unobtrusive. tion advantage under high loads of up to (e.g., at 2,000 rpm and 100 Nm by 9 g/ 0.1 bar friction mean effective pressure kWh BSFC). This behaviour is less severe (FMEP), which corresponds to as much for the steel piston, but Mahle recom- COMBUSTION as 3 g/kWh break specific fuel consump- mends that the piston cooling is not shut- tion (BSFC). Under low loads, the fric- off, particularly for steel pistons, because The indicated specific fuel consumption tional loss behaviour of the steel and alu- otherwise the engine oil can deteriorate (ISFC) in all cases is significantly lower minium variants can be considered essen- strongly on the inside of the cooling gal- with steel pistons than with aluminium tially comparable (measurement accuracy lery and beneath the centre of the com- pistons. The operating map improve- ΔFMEP = ± 0.03 bar). The equivalent bustion bowl. ments due to thermodynamic advantages level of friction in this comparison is Due to the tighter installation clearance range between 4 and 8 g/kWh. The ther- achieved with an aluminium piston with of steel pistons, no acoustic issues are modynamics are affected by the follow- relatively high installation clearance. As generally expected for a cold engine, but ing parameters: the clearance is reduced, the frictional even in the warm state the engine :: Blow-by quantity: For measurements loss advantage of the steel piston becomes more pronounced. Differences in frictional losses occur particularly, when the piston cooling is shut-off. The frictional loss is then neutral only for a limited set of conditions, as the piston temperature increases significantly for both variants (e.g., at 1,500 rpm and 50 Nm at the bowl rim by 35 °C for the aluminium piston and by 60 °C for the steel piston). For ranges with somewhat higher loads, the rise in temperature increases, leading to overlap due to thermal expansion of the aluminium piston even though the high installation clearance. The frictional loss then rises sharply and causes an overall increase in fuel con- ❸ Loss distribution for the operating point 1500 rpm, 200 Nm (left), fuel consumption advantage of the steel sumption – despite the advantages of the piston at selected operating points (right)

26 www.autotechreview.com with identical ring packs, the steel pis- Temperature cylinder 2 bowl rim, thrust side ton results in 15 to 45 % less blow-by. 300 300 [°C] About 30 % (at partial load) or 10 % [°C] 280 280 bowl rim (at high load) of the advantages in fuel bowl rim T T consumption can be ascribed to the 260 260 difference in blow-by. 01020 8121620 :: Higher wall temperatures in the com- EGR [%] HR50 [°CA a TDC] 2000 rpm, bustion chamber: The tested configura- 15.98 bar IMEP tion exhibits a difference of about 50 Aluminium piston Steel piston °C in the maximum component tem- 300 300 [°C] perature at the bowl rim for steel and [°C] Baseline setting 280 280 (ISO HR50, ISO NO , bowl rim aluminium pistons with identical cool- bowl rim x T T poil = 2 bar, Toil = 90 °C) ing (steel piston: maximum 430 °C, 260 260 measured near the surface). The differ- 10 20 50 70 90 110 ence is even greater at the centre of the Oil ﬂowfor four pistons [l/min] Toil piston [°C] bowl, at 90 °C, as this area is more dif- ❹ Changes in piston temperature at the bowl rim by varying engine parameters and by varying piston cooling ficult to cool with steel pistons. The first ring groove shows the same temperature level for both piston types to the high thermal conductivity and ton would attain the component temper- (maximum 190 °C). The tests indicate larger material cross sections, and is then atures of the steel piston. A variation in only a minor effect of piston tempera- dissipated by the cooling oil. The heat temperature of up to 15 °C can be ture on fuel consumption. The loss dis- transport in the steel piston, in contrast, is achieved by means of the EGR rate and tribution from the pressure curve anal- rather limited and takes place primarily around 20 °C if the centre of combus- ysis indicates similar or slightly lower by means of the cooling oil. tion is shifted to an extreme extent. wall heat losses for the steel piston. Starting from this behaviour, the Piston cooling can have a significant :: Reduced top land volume: The first effects of various parameters on the pis- direct effect on the piston temperature piston ring on the steel piston can be ton temperature were investigated. This without negatively affecting the engine placed at a higher position than on the is shown as an example for the bowl thermodynamics to any substantial aluminium piston. The smaller top rim of the piston at 2,000 rpm and 250 degree. A change of 70 °C in the cooling land volume is advantageous for CO Nm, 4. The base temperature (series oil temperature changes the bowl rim emissions of the steel piston and has a settings) is 260 °C for aluminium and temperature by about 35 °C. The effect is positive influence on the effective com- 277 °C for steel. It is immediately evi- nearly linear. Fuel consumption and pression ratio for the same combustion dent that the influence of the parame- engine friction are barely altered, 5. For a chamber geometry. It is beneficial to ters on the temperature is similar for difference in cooling oil temperature of 30 reduce this volume, which makes this both variants (similar gradient of the °C, the steel and aluminium piston would a system advantage of the steel piston. temperature curves). There is, however, have the same bowl rim temperature. The The combustion process of the steel pis- no setting for which the aluminium pis- change in cooling oil flow rate has the ton is characterised by a shorter duration in the second half of the combustion Indicated speciﬁc fuel consumption Friction mean effective pressure cycle as a result of the effects described. 198 1.00 The 90 % heat release point is up to 5 196 0.98 °CA earlier, with the centre of combus- 194 tion at the same location. 3 shows an 192 0.96 FMEP [bar] example of loss distribution for an oper- ISFC [g/kWh] 190 ating point with identical nitrogen oxide 0.94 *See note emissions and the same position of cen- 188 tre of combustion, as well as the fuel Temperature of bowl Ratio of engine oil enthalpy rim thrust side, cyl. 2 (for energy balance) 2000 rpm 290 consumption results at a few selected 18 15.98 bar IMEP Aluminium piston operating map points (1 to 7), which rep- 280 16 Steel piston

resent a “normal operation”. [°C] [%] 270 oil total bowl rim 14 Baseline setting X T (ISO HR50, ISO NO , 260 x poil = 2 bar, Toil = 90 °C) PISTON TEMPERATURES 12 250 *See note 50 70 90 110 50 70 90 110 T [°C] T [°C] The temperature distribution in the alu- oil piston oil piston minium and steel piston are fundamen- *Heating of base engine oil necessary tally different. In the aluminium piston, ❺ Variation of temperature of the piston cooling oil (base engine at a constant 90 °C): effects on piston the heat is distributed more uniformly due temperature, fuel consumption, engine friction, and overall proportion of the oil heat in the split of losses autotechreview October 2014 Volume 3 | Issue 10 27 Cover Story PISTONS & RINGS

❻ Mahle passenger car steel piston range (A: Monotherm, B: TopWeld, C: MonoGuide)

potential to vary the bowl rim tempera- ference in thermal expansion between extends to the ring area, optimal guid- ture by up to 50 °C. steel piston and aluminium cylinder ance in the liner with good noise behav- An optimised oil flow rate provides the block, the operating clearance increases iour. This type of piston is therefore also opportunity to adjust the piston tempera- as the temperature rises, and the piston perfectly suited for use in engines with ture in a targeted manner with a reasona- may strike the cylinder wall with greater aluminium crankcases. ble level of effort. This is better achieved impact. This can be counteracted by opti- for the steel piston than for the alumin- mising the piston installation clearance, ium piston. For small oil flow volumes, the shape of the piston, and the piston OUTLOOK the steel piston exhibits a friction advan- pin offset. tage of 0.04 bar (corresponding to 1 g/ It is expected that the steel piston will kWh BSFC). This is due to the fact that find wider application in passenger car the temperature at the skirt rises by 15 °C MAHLE PASSENGER CAR DIESEL series production in addition to the alu- for a smaller oil volume flow, and the STEEL PISTONS minium piston. The attainable fuel con- reduced oil viscosity has a positive effect sumption advantages and the possible use on friction. In contrast, small oil volume The so-called Monotherm piston has at maximum combustion pressures will flows are critical for steel pistons with been proven and tested millions of times surely be a motivating factor. respect to cooling channel coking and sur- in commercial vehicle engines for over 10 face scaling. years and will be employed in the first References passenger car diesel engines in 2014. The [1] Baberg, A.; Freidhager, M.; Mergler, H.; Schmidt, K.: Aspects of Piston Material Choice for thermally decoupled and flexible shaft of Diesel Engines. In: MTZ worldwide 73 (2012), No. CHALLENGES FOR the one-piece forged piston has the great- 12, pp. 26-30 [2] Schneider, S.; Ehnis, H.; Schreer, K.: Analyse SERIES-PRODUCTION READINESS est potential for CO2 savings at the low- est weight, 6. von Aluminium- und Stahlkolben – Vergleich von Reibung, Kolbentemperatur und Verbrennung. Since the steel piston has a substantially Another concept in the Mahle passen- International Stuttgart Symposium, 2013 higher temperature level than the alumin- ger car steel piston portfolio is the so- [3] Deuß, T.; Ehnis, H.; Freier, R.; Künzel, R.: ium piston, as demonstrated, scaling can called TopWeld piston, made from two Friction Power Measurements of a Fired Diesel En- gine Piston Group Potentials. In: MTZ worldwide occur at severely thermally loaded loca- parts joined together. Characterised by a 71 (2010), No. 5, pp. 20-24 tions such as the bowl rim. This scaling closed cooling gallery and an attached [4] Schäfer, B.-H.; Schneider, V.; Geisselbrecht, layer and the scaling scars that form can skirt, this piston type is suitable for the M.: Real-time Kolbentemperaturmessungen mit einem auf Telemetrie basierenden Datenübertra- become initiation points for bowl rim highest peak cylinder pressures. Its gungssystem – Messtechnikapplikation und erste cracks during subsequent operation. greater rigidity allows for smaller wall Ergebnisse. 10th Stuttgart International Symposi- Another challenge is the tendency of the thicknesses, especially between the com- um, 2010 piston cooling oil to coke in the cooling bustion chamber and the cooling channel, [5] Stitterich, E.; Geisselbrecht, M.; Künzel, R.: Influence of cooling channel design on piston tem- channel and at the inner form of the pis- which in turn makes it possible to opti- perature of HSD engines. 13th Stuttgart Interna- ton. The coke oil deposits reduce the cool- mally cool the bowl rim. tional Symposium, 2013 ing efficiency and thus additionally aggra- The consistent on-going development vate the temperature problems at the and optimisation of the advantages of bowl rim. The soot input from combus- both piston concepts results in the new tion also has a rather significant effect on so-called MonoGuide piston, which is oil aging and the tendency for carbon also a two-part joined piston. Analogous build-up. to the Monotherm piston, it is character- The development of steel pistons for ised by a flexible, decoupled skirt. This engines with aluminium crankcases pre- gives the piston excellent seizure resist- Read this article on sents another challenge. Due to the dif- ance and, together with the skirt that www.autotechreview.com

28 www.autotechreview.com YOUR PARTNER IN THE AUTOMOTIVE INDUSTRY

TYROLIT in India +91 80 23121811 | [email protected]

A Company of the SWAROVSKI Group www.tyrolit.com Cover Story PISTONS & RINGS LOWER FRICTION LOSSES WITH NEW PISTON RING COATING

Piston rings offer a significant potential to reduce fuel consumption and CO2 emissions of internal combustion engines. Federal-Mogul has developed a new type of piston ring coating called DuroGlide, which can be used to reduce friction power loss substantially, while ensuring a high level of robustness. The coating’s excellent wear resistance plus a scuff resistance that is superior to widely used piston ring coatings make DuroGlide the coat-

30 www.autotechreview.com ing of choice for high loads in gas- Authors RISING PISTON RING LOADS oline and diesel engines. The fundamental driver in the development of internal combustion engines is increasingly represented by the stronger focus on better fuel efficiency and meeting stricter exhaust emission legislation. DR. MARCUS KENNEDY is Manager of Physical Coatings at the This development strategy leads to greater Federal-Mogul Burscheid GmbH in challenges in developing engine compo- Burscheid (Germany). nents, and piston rings in particular. At powered partial load conditions, the ring pack contributes up to 25 % of the total mechanical engine friction loss, which corresponds to up to 4 % of fuel consumption. The challenge lies in reducing friction power loss, while also master- DR. STEFFEN HOPPE ing the thermo-mechanical and tribologi- is Director Technology Rings and Liners at the Federal-Mogul cal load conditions that piston rings must Burscheid GmbH in endure owing to smoother cylinder bores, Burscheid (Germany). reduced lubrication, and the use of alternative fuels. This is why piston ring running face robustness, as described by wear resistance and particularly scuff resistance, plays an increasing role.

JOHANNES ESSER STATE OF THE ART TECHNOLOGY is Director Engineering Rings and Liners at the Federal-Mogul OF CARBON-BASED PISTON Burscheid GmbH in RING COATINGS Burscheid (Germany). Ever since coatings were acknowledged as an essential design feature they have inev- itably been a focal point for improving friction losses in the tribological system of piston ring and cylinder bore. Carbon- based, diamond-like coatings (Diamond- like Carbon, DLC) are particularly used for components, which undergo solid-to- solid contact with other components during operation. The excellent properties of DLC coatings ensue from the generation of a thermally and mechanically induced transformation of the top layer of the DLC film into a material of lower shear strength than the layer itself, and which therefore becomes self-lubricating. Traditional DLC coatings are limited in their application on piston rings by the following features: :: Typical layer thicknesses are lying in the region of a few microns, which limits coating lifetimes. If the coating is thicker, the risk of delamination increases due to typical internal stresses, and :: Hard DLC coatings make it difficult to achieve very smooth piston ring running surfaces to ensure excellent autotechreview October 2014 Volume 3 | Issue 10 31 Cover Story PISTONS & RINGS

❶ Scanning electron microscope shot of the fracture surface of a DuroGlide piston ring coating

friction levels and avoid cylinder To facilitate a wider exploitation of the gasoline and diesel engines. 1 depicts the bore wear. DLC friction power reduction potential in homogeneous, single-layer structure of DLC piston ring coatings currently are highly charged gasoline and diesel the new hydrogen-free, carbon-based pis- often used as a running-in layer on other engines, a DLC coating with even better ton ring coating. Due to the high amount wear-resistant coatings. The hydrogen- wear resistance and considerably greater of sp3-hybridised carbon (tetrahedral containing DLC technology called Car- coating thickness is required. structure), DuroGlide can be applied with boGlide from Federal-Mogul produced the a layer hardness of up to 5,000 HV 0.2. In first coating that could be applied in contrast to existing hydrogen-free DLC about 10 µm of thickness in combination FEATURES OF THE NEW COATING coatings, the internal stresses of the new with an increased wear resistance [1, 2]. coating are reduced during the new coat- In the meantime, this coating system is DuroGlide is the first DLC coating that is ing process, developed in cooperation in serial production for gasoline engines. suitable for lifetime use in highly loaded with the Fraunhofer Institute for Material

100

Relative coefﬁcient of friction [-] 0 Steel nitrided CKS/GDC CrN CarboGlide DuroGlide ❷ Relative comparison of the friction coefficient of various piston ring coatings, measured in an oscillating frictional wear tribometer under boundary lubrication conditions

32 www.autotechreview.com ❸ Difference of the friction power, depending on pressure and rpm, shown in percent for a DuroGlide compression ring in the top groove as compared to the industry standard in passenger car diesel engines; measured in a floating liner engine

and Beam Technology, IWS Dresden. The Keramik-Schicht: CKS) and Goetze dia- piston ring coating, extensive endurance coating has a layer thickness of up to 25 mond coating (GDC) as well as physical and overload tests in highly loaded pas- μm with an excellent adhesion to cast vapour deposition (PVD) coatings such as senger car diesel engines were carried out iron and or steel surfaces. The tempera- CrN, the use of DuroGlide reduces the with combustion pressures of up to 200 ture resistance of up to 500 °C allows the coefficient of friction by up to 60 %. bar and a specific output of up to 70 application in diesel engines. A coating To measure the friction power kW/l. 4 0 depicts the engine test bed topography that is already close to the fin- improvement of DuroGlide in the engine, results by the mean radial ring wear after ished design as well as optimised manu- friction loss tests were conducted on a so- up to 500 h. The results show that ring facturing processes result in very smooth called floating liner single cylinder gaso- wear can be greatly reduced by up to 50 piston ring surfaces. line engine. % with DuroGlide in comparison to the 3 shows the relative friction power piston ring coatings (GDC and PVD-CrN) differences of DuroGlide measured at dif- used today. PERFORMANCE FEATURES ferent operating conditions (number of Apart from the wear resistance, which revolutions, mean pressure) in the fired impacts the lifetime, the ring coating’s The most important goals during the engine in contrast to CKS-coated piston performance under overload conditions development of the new coating were to rings, which were used as a reference. and with reduced lubrication is of increas- bring down the mechanical friction loss The piston ring design and piston ring ing importance. 5 shows the results of a and to substantially increase the robust- tension (tangential load) remained the rig test, which was designed to determine ness of carbon-based coating systems for same. The greatest benefit was demon- scuff resistance under overload condi- piston rings. 2 shows a relative compari- strated at 0 to 180 °CA (shortly after igni- tions. Escalated scuffing is induced by son of the coefficients of friction found in tion) and at medium effective pressures: exceeding a friction coefficient of 0.3, the piston ring coatings used today in gas- at 1000 rpm and 6 bar of mean effective when normal force was increased up to oline and diesel engines. The coefficient pressure (MEP), the friction loss benefit 700 N at regular time intervals. of friction was measured outside the was 10 %. Considering the oil ring con- Today’s coated compression rings engine under test conditions, which repre- tributes up to 40 % of the mechanical showed first signs of scuffing after 120 sent a high mixed friction share while friction loss, the application of DuroGlide min (CKS) and 157 min (CrN) of test using oil without additives. oils rings should make a further reduction duration respectively. The DuroGlide Compared to chromium-based coatings of friction losses achievable. coated compression rings, however, fin- such as chrome ceramic coating (Chrom- To examine the robustness of the new ished the complete test run up to the autotechreview October 2014 Volume 3 | Issue 10 33 Cover Story PISTONS & RINGS

10 700 8 600 6 GDC, CrN 500 400 4 Mean radial ring wear [µm] DuroGlide Scuff 300 2 200 0 resistance [min] 100

0 100 200 300 400 500 0 Engine running time [h] CKS/GDC CrN DuroGlide

❹ Mean radial wear of DuroGlide compression rings in highly ❺ Scuff resistance measured in a non-engine overload test, comparing DuroGlide to CKS/GDC charged passenger car diesel engines and PVD-CrN coated piston rings

maximum test duration of 650 min running surface designs, it is equally duced, which exceeds the previous without any signs of scuffing on the pis- suited for compression rings and oil rings. boundaries of robustness and friction ton ring running surface or the cylinder 6 shows a conceptual set-up of a power reduction. The coated piston rings bore. The excellent scuff resistance of piston ring pack for passenger car diesel show the highest level of wear and scuff DuroGlide was also confirmed by a spe- and gasoline engines. As the top com- resistance, when compared to all conven- cially designed thermal shock test car- pression ring and oil ring each contrib- tional piston ring coatings and thus con- ried out in a highly charged passenger ute around 40 % to the mechanical fric- tribute to a fuel efficiency improvement of car diesel engine. tion loss, DuroGlide is preferred for up to 1.5 %. This is equivalent to a reduc-

these two ring types. tion of CO2 emissions by up to 3 g/km, Along with the benefit resulting from depending on the engine application. APPLICATION POSITIONING the running surface coating itself, an opti- Based on the development of plasma- misation of friction and functional proper- assisted coating process technology and While the first hydrogenous DLC genera- ties is possible by adjusting the piston the application of special smoothing pro- tions were marked by very good friction ring design with regard to tangential force, cesses, an exceptional coating thickness properties and an excellent running-in axial and radial dimensions, running sur- of 25 µm can be achieved, which makes behaviour on grey cast iron and alumin- face topography, and a combination of this product lifetime durable even under ium cylinders, the DuroGlide coating has closed gap values. the most severe operating conditions and been designed as a lifetime coating from superior in comparison to alternatively day one making it an option for highly available technologies such as PVD-based loaded gasoline engines but even more so SUMMARY AND OUTLOOK CrCN with embedded carbon or multi- for the diesel engines. As DuroGlide can layer systems like very thin hydrogen-free be applied to base materials such as cast With the development of DuroGlide, a DLC (< 2 µm) on PVD-CrN. iron and steel and is feasible for different new type of piston ring coating was intro- On-going and comprehensive engine validation is pursuing the goal of rapid launch of serial production of this technology.

Design detail References Basic design Measures Ring running surface [1] Esser, J.; Hoppe, S.; Kennedy, M.: Kolben- ringbeschichtung senkt innermotorische Reibung und Kraftstoffverbrauch im Ottomotor. In: MTZ 73 (2012), No. 3 [2] Esser, J.; Hoppe, S.; Mittler, R.: Kolbenring auslegung für Ottomotoren im Spannungsfeld von

Reduced tangential force Reibungsreduzierung und Funktionsverhalten. Lower axial height VDI-Fachtagung Zylinderlaufbahnen, Kolben, Reduced radial wall thickness Pleuel, Baden-Baden, June 2010 Friction work-optimised coating Optimised base material

Read this article on ❻ Examples of low-friction piston ring packages for passenger car engines www.autotechreview.com

34 www.autotechreview.com 21 x 27.9cm (+.5cm bleed) Cover Story PISTONS & RINGS

36 www.autotechreview.com GAS-LUBRICATED MECHANICAL FACE RINGS FOR CO2 REDUCTION

Freudenberg Sealing Technologies has developed a new gas-lubricated mechanical face ring that uses an aerodynamic structure to generate a cushion of air as the shaft rotates. It is particularly suitable for use as a crankshaft seal and is claimed to cut CO2 emissions by 0.5 g/km and more in the NEDC. The system could go into series production in 2017.

Authors REDUCE FRICTION spring. The rotating shaft drags oil forced into the sealing gap along the conveyor The European Union (EU) has the goal of screws back into the crankcase. The

reducing average CO2 fleet emissions for sheering forces in the oil and the solid

newly registered vehicles to 95 g CO2/km body contact in the sealing gap lead to

by 2020 and prospectively to 75 g CO2/km frictional losses. In contrast, the opera- by 2025. To reach this goal, the EU has tion of a gas-lubricated mechanical face M. SC. SÖREN NEUBERGER introduced annual fines beginning in 2012 seal entails no solid body contact, and is Project Manager Sealing that are due in case of non-compliance the frictional losses in the gas film are Development at Freudenberg Sealing with manufacturer-specific fleet limits on significantly less due to the low viscosity Technologies GmbH & Co. KG in Weinheim (Germany). CO2 emissions. As of 2020, after an intro- of the air, which allows a reduction in ductory phase with steadily rising fines, fuel consumption and the associated the penalty comes to € 95 for each gram emissions [2, 3]. and each vehicle exceeding the limit [1]. Gas-lubricated mechanical face seals To comply with the limit, automobile have been used for about 30 years in manufacturers must, among other things, industrial applications such as compres- reduce frictional losses from components sors, expanders, pumps and stirrers, at a DR.-ING. EBERHARD BOCK in the engine and the drivetrain. This wide range of pressures and circumferen- is Director Advanced Product includes the crankshaft seal on the trans- tial speeds [3, 4]. Compared to conventional Engineering Europa at Freudenberg mission side. It contributes 0.5 to 1 g gas-lubricated mechanical face seals, the Sealing Technologies GmbH & Co. KG in Weinheim (Germany). CO2/km to emissions under the New sealing of a crankshaft poses a technical European Drive Cycle (NEDC) – depend- challenge: only an extremely small instal- ing on the design and the vehicle. lation space is available. 1 shows the seal Through the use of a gas-lubricated developed and patented by Burgmann in mechanical face ring, the contribution to 1999 (generation 1) as a schematic sec- [5] CO2 emissions can be reduced to less tional view .

than 0.1 g of CO2/km per seal. Freuden- The concept consists of many individ- PROF. DR.-ING. berg Sealing Technologies has developed ual parts and was successfully tested, but HABIL. WERNER HAAS a sealing system that contributes to envi- at that time, it was unable to make is Division Manager Sealing ronmentally friendly mobility, under the inroads into the automotive sector. First of Technology at the Institute for [2] Machine Elements of University of Levitex brand name . all, the idea of CO2 savings was not as Stuttgart (Germany). prevalent in the market as it is today; and secondly, the manufacturing costs would CRANKSHAFT SEALING SYSTEMS have significantly exceeded the savings from friction reduction [6]. Crankshaft seals have been manufactured in a range of variations for decades. The Simmerring with garter spring GAS-LUBRICATED MECHANICAL DR. RER. NAT. KLAUS LANG continues to be used. Newer develop- FACE SEAL is Senior Technical Consultant/ Group ments include the radial shaft seals with Leader Software Development at EagleBurgmann Germany GmbH & a seal lip made of polytetrafluorethylene After Burgmann was integrated into the Co. KG in Wolfratshausen (Germany) (PTFE) or elastomer without garter Freudenberg corporate group, Freuden- autotechreview October 2014 Volume 3 | Issue 10 37 Cover Story PISTONS & RINGS

the fluid in the seal gap. In this case – small seal gaps and low Reynolds numbers – the description relies on the stationary Reynolds differential equation in polar coordinates (here – without taking inertial force into account – a transformation in the rotating system with gas groove occurred) (r,θ), 4 (b) [4]:

3 3 __1 __∂ ____ρ h __∂p __∂ ____r ρ h __∂p r 12 µ + 12 µ Eq. 1 ∂θ ( ∂θ ) ∂r ( ∂r ) ___r ω __∂ = ( h) 2 ∂θ ρ

where p = pressure, h = gap height field ρ = density ω = angular velocity, µ = dynamic viscosity, coordinate system based on ④ (b). The real gas equation describes the relationship between ρ and p:

p Eq. 2 ______ρ(p,T)= Z(p,T) R T ❶ Schematic sectional view Levitex generation 1 [5] where z = real gas factor, R = specific gas constant, T = temperature, at the iso- berg Sealing Technologies took up the driver using an elastomer press-fit. This thermal temperature boundary condition, [4] idea again in 2010. The company devel- has the function of secondary sealing Tgas(r) = Tseal face(r) applies . oped and patented a new concept with a and frictional torque support. The mating The energy balance and thermal cou- high degree of innovation and signifi- ring unit is pressed onto the crankshaft pling of the gas film with the primary and cantly reduced manufacturing costs (gen- and rotates with the crankshaft revolu- mating rings is completed with the angle- eration 2). 2 shows the schematic sections. The metallic press-fit simultane- averaged energy conservation equation in tional view of the so-called Levitex gener- ously forms the secondary seal between the radial direction: ation 2 in its installed form [7, 8]. the driver and the crankshaft. As an

2 During assembly, the elastomer com- option, this can also be carried out with 1 (vr) Eq. 3 q+w =____ m∙ ∂r H+____ ponent is deflected and the primary ring a seal coating [7, 8]. 2 π r ( 2 ) is pushed against the mating ring. The elastomer component is firmly affixed to where q = the heat flow density of the housing. It compensates for axial and MODE OF OPERATION the primary ring, w = the work done by radial installation tolerances as well as frictional force, m∙ = mass flow rate in the vibrations introduced during operation. In During rotation, the separation of the pri- seal gap, H = enthalpy of the fluid, and [4] addition, the elastomer component takes mary and mating rings takes place with vr = radial gap flow velocity . over the function of secondary sealing the help of aerodynamically effective The system consisting of Eq. 1 to 3 is between the primary ring and the housing structures – spiral grooves – on the seal- solved with the help of a finite difference as well as the frictional torque support. ing face of the mating ring. 3 (a) shows a method, aided by fluid and gas groove The housing is firmly connected to the section of the seal face with a unidirec- data set out in tabular form. Here the crankcase with frictional locking both tional gas groove. In the cross-section, the mechanical and thermal simulations of radially and axially. spiral groove is configured in the direction primary and mating rings are carried out In the variant shown, the secondary of flow in tapered form and is only a few in rotationally symmetrical FEM models. seal between the housing and the crank- mm deep. During rotation, air is drawn The mechanical and thermal boundary case takes place with a sealing paint, but against a sealing dam. The resulting drag values of the primary and mating ring are it can also be executed with a partly rub- flow pressure, ③ (b) separates the seal appropriately indicated, depending on the berised design. The primary ring, the faces (slide faces) [3, 4]. application. The coupling of the rings to elastomer component and the housing The pressure between the primary and the gas film takes place through the use of form the stationary primary ring unit. mating ring can be described with the a one-dimensional (angle-averaged) inter- The mating ring unit consists of the mat- basic equation of fluid dynamics for con- face, ④ (b) [4]. ing ring and the driver with an elastomer servation of momentum, mass and The gap-opening force can also be cal- press-fit. The mating ring is fixed in the energy, and with the equation of state for culated from the pressure distribution.

38 www.autotechreview.com The gap height between the primary and mating seals then adjusts to equilibrium with the gap-closing forces (spring force and compressive forces on the primary ring from outside), ④ (a), [3, 4]. The force-distance curve of the gap- opening force is, among other things, dependent on the shape of the spiral grooves and the slide velocity. The increase in the tangent in the gap at equilibrium (equilibrium of forces) corresponds to gap rigidity [4]. The Seal analysis called simulation software from Mechanical Seal Technol- ogy Inc. and auxiliary modules developed by Freudenberg Sealing Technologies were used in the simulation of the mechanical face seal and simulate the system depicted in ②, ③ and ④ [8].

❷ Schematic sectional view Levitex generation 2 [7, 8] TEST RESULTS OF FRICTIONAL TORQUE MEASUREMENT

The frictional torque measurement was carried out on a seal test stand with an aero-statically supported test cell. The construction of the seal test stand allows a highly precise measurement of the frictional torque. The resolution of the recorded frictional torque is in the range of 2.5 mNm [8]. 5 shows the average value of the frictional torque for three PTFE radial shaft seals and the experimentally determined ❸ Sector of the seal face with gas groove (a) and pressure distribution on the seal face (b) Levitex generation 2 frictional model across engine rotational speeds. The frictional torque of the PTFE radial shaft seal rings is shown for oil temperatures of 30, 60, and 90 °C. The Levitex generation 2 frictional torque model shows the maximum expected frictional torque of the seal at various lubrication conditions, temperatures and production tolerances [8]. At slide velocities below 1.2 m/s, the frictional torque is slightly higher than that of a PTFE radial shaft seal; but it falls exponentially in the range of an idling engine‘s rpms. At slide velocities above the engine idling slide speed (>3.12 m/s), Levitex produces up to 0.28 Nm less frictional torque than PTFE radial shaft seals do, depending on the temperature and rotational speed. At 2,000 rpm, the frictional savings have already reached 48 to 67 W compared to a PTFE radial shaft seal ring, depending on the ❹ Force-distance curve with gap in equilibrium (a) (schematic view) [3] and coupling between slide and seal temperature. Under the NEDC, this deliv- faces in the simulation model (b) autotechreview October 2014 Volume 3 | Issue 10 39 Cover Story PISTONS & RINGS

❺ Frictional torque PTFE radial shaft seal rings and Levitex [8]

European Union, Brussels, 2009 ers savings of 1.3 g of CO2/km for a gaso- unit (rotor) and the primary ring unit (sta- line engine with CO emissions of 161.5 g tor) and tolerances critical for functional- [2] Bock, E.; Raclot, I.; Lutaud, D.: POP: Reibun 2 gsoptimierte PTFE-Simmerringe. 16th Internation- [8] of CO2/km . ity lie within the real-life limit range and al Sealing Conference, Stuttgart, 2010 beyond it. [3] Müller, H. K.: Abdichtung bewegter Maschi- nenteile. Waiblingen: publishing house Ursula Müller, 1990 FUNCTIONAL TESTS [4] Lebeck, A. O.: Principle and Design of Me- INTERPRETATION AND OUTLOOK chanical Face Seals. New York/Chichister/Bris- Functional tests according to standard bane/Toronto/Singapore: John Wiley & Sons Inc., 1991 requirements (>50 seals) were addition- The results of the functional tests show [5] Patent WO 99/00618: Gleitringdichtung für ally carried out: that the new generation of the seal is Kurbelwellen. German Patent Office, Munich, :: Frictional torque measurements up to suited for use at the transmission end of 1999 41.6 m/s (= 8,000 rpm) at different the crankshaft in internal combustion [6] Neuberger, S. et. al: Auf dem Weg zu 95 g – Gasgeschmierte Gleitringdichtungen im Verbren- pressure levels (-200 mbar up to 200 engines. Parallel to the functional tests at nungsmotor. 17th International Sealing Confer- mbar), Freudenberg Sealing Technologies, leading ence, Stuttgart, 2012 :: Endurance test of more than 3,000 h at European automakers have undertaken [7] Patentanmeldung DE 102011114349A1: Gleitringdichtung mit balgartigem Federmittel. 150 °C with 50 % oil level (severe con- critical engine tests to evaluate the new German Patent Office, Munich, 2011

ditions), varying rpm, and standstill sealing concept. [8] Neuberger, S.; Haas, W.: CO2NSEAL – phases to test leak tightness, Based on the positive results and an Dynamische Dichtsysteme zur CO2-Reduktion […]. BMBF research report, Bonn, 2013 :: Axial and radial vibration in the shaft accumulation of expertise, Levitex seals in a new condition – and in an aged are now being prepared with a more condition after an endurance test, advanced design. At the current state of :: Low temperature cycles from -40 going development, series production by 2017 is up to 90 °C, including cold-start a realistic goal. At present, there is no procedures, other known sealing system that provides

:: Dust tests with Arizona “fine” class crankshafts with comparable CO2 savings dust from exterior, potential. In the event of a successful :: Wear testing in the mixed friction area launch into series production, the use of without lubricant to simulate start-stop the concept is also envisioned at the front- conditions, end of the crankshaft and at the transmis- :: Engine test at an unaffiliated university sion input. This would increase the poten- [8] , and tial to save CO2 considerably. :: Static airtightness at various pressure stages. References [1] Regulation No. 443/2009 of the European All tests were conducted in such a way Read this article on Parliament and of the Council of 23rd April 2009. that the misalignments of the mating ring www.autotechreview.com

40 www.autotechreview.com

Cover Story PISTONS & RINGS ASPECTS OF PISTON MATERIAL CHOICE FOR DIESEL ENGINES

A new Federal-Mogul aluminium piston for a triple turbo diesel engine with 93 kW/l power illustrates that aluminium continues to offer potential for extreme engine applications. At the same time, passenger car engines with ignition pressures greater than 220 bar and more than 100 kW/l of specific output will necessitate steel pistons. Steel designs for such extreme applications require special attention to thermal management, though. In this article, Federal-Mogul shows different engineering aspects of aluminium and steel pistons.

42 www.autotechreview.com Authors RISING STRESS FOR ALUMINIUM PISTONS FOR HIGH- PISTON MATERIALS PERFORMANCE DIESEL ENGINES

As the efficiency of passenger car diesel High-performance, highly-charged pas- engines is increased, the piston tempera- senger car diesel engines are generally ture level in the combustion chamber seen as the touchstone for Al pistons as goes up. Sometimes this can take con- the thermal and mechanical piston loads ARND BABERG is Chief Engineer Product Engineering ventional aluminium (Al) piston designs in the combustion chamber are so at Federal-Mogul in Nuremberg to the limit of material strength. The immense that engine designers are con- (Germany). threshold for this is somewhere around cerned the lightweight material might 400 °C. Close to, at, or above this level eventually fail. Typically it is the bowl the bowl rim is exposed to so much heat rim where cracks initiate. Therefore, the that cracks can begin to form. This is as first logical measure is to reinforce this much a matter of the material as it is a area. It is the material itself, which sug- question of design. gests a solution: although the casting By applying state-of-the-art design ele- process has already been optimised to MARCUS FREIDHAGER ments Federal-Mogul manufactured and exploit the maximum cooling speed that is Program Manager and Application Engineer at Federal-Mogul in supplied an Al piston for an extremely still results in a flawless product, the Nuremberg (Germany). highly charged 3 l full-Al diesel engine cooling is still too slow for a maximum that delivers 93 kW/l. This new light material strength at the bowl rim. In a vehicle diesel (LVD) Al piston technology highly-charged engine, the rim can be is currently used in applications with up exposed to so much heat that the to 420 °C. medium-fine grain of the alloy matrix While this Al application clearly goes can become the starting point of crack beyond what was considered feasible, it is formation. Once this happens, the HARALD MERGLER clear that even higher ignition pressures thermo-mechanical fatigue and high- is Program Manager and Application and higher specific output will necessitate cycle fatigue can increase the crack Engineer at Federal-Mogul in 1 Nuremberg (Germany). steel as piston material. However, apply- length and depth, . ing steel to an extreme passenger car pis- Understanding this mechanism, Fed- ton application requires a similar level of eral-Mogul developed a process that attention to temperature, and gallery changes the alloy matrix in the critical design in particular, as does the Al piston. area of the bowl rim. This treatment is Maximising the gallery geometry, a com- called Durabowl and refers to the effect of bination of dissimilar steels for crown and locally remelting the bowl rim along its

KLAUS SCHMIDT skirt, plus protective coatings can be 360° circumference to increase the mate- iis Head of the Engine Testing required to avoid overly high crown tem- rial strength. The amount of energy used Facilities at Federal-Mogul in peratures. These could cause oxidation/ for this re-melt process is tightly con- Nuremberg (Germany). scaling, thermally induced crack forma- trolled to produce an exactly defined tion, or overloading of the oil (cracking). diameter and depth of the molten Al

❶ Thermo-mechanical fatigue induced by micro-plasticity after thermal cycling autotechreview October 2014 Volume 3 | Issue 10 43 Cover Story PISTONS & RINGS

the gallery and/ or between the gallery and the cast-in Alfin insert. The first production application of the raised gallery piston keeps the piston at temperatures much lower than the acceptable limit of 400 °C. Under the same conditions, a standard piston’s bowl rim stresses are 43 % higher and its temperature reaches 440 °C, close to the melting point of the first metal phases in the matrix. Depend- ing on the application requirements the optimum gallery position and design can be flexibly defined. As standard test procedures would not have sufficed to identify the location of possible defects in the critical area, a new two-dimensional (2D) ultrasonic analysis system was developed. This non-destruc- tive method accurately determines the size and position of the gallery and Alfin insert, and any possible casting defects. Within 30 s the process provides the results in 125,000 test points to ensure consistent quality in the finished high-precision component. This 2D data also serves to further improve manufacturing ❷ Comparison of the Al alloy grain size before (bottom left) and after the Durabowl treatment (bottom right) processes and core process parameters.

zone. As the continuous process proceeds improved by more than 10 %, at the pin ASPECTS OF STEEL PISTONS along the full 360° along the rim, the bore the improvement is around 5 %. small mass of melt rapidly solidifies. This Alternatively, the shape of the gallery At first sight, the temperature strength of results in a considerably finer grain of the can be adapted to the application. While steel suggests that the material is auto- alloy in the re-molten zones, 2. this is not overly complex from a design matically the superior solution for high- Extensive testing has shown that the point of view, it is quite challenging to performance passenger car diesel engines. refined grain is much less prone to the control the casting process to ensure that However, Al conducts heat three times crack formation mechanism, 3. In direct there is enough material of consistent better than steel, which is the reason why comparison to a conventional bowl rim as cavity-free quality between the bowl and steel pistons can be hotter by 50 to 100 K cast, the Durabowl piston lasted four times as long under identical test conditions – without any crack formation. Therefore, this process has quickly 1000 become a proven and widely utilised element of optimising Al pistons for diesel engines with a high specific output. 800

600 IMPROVED HEAT TRANSFER IN ALUMINIUM PISTONS

400 As the amount of heat is so great in the edge crack [h] bowl area, a second consequence is to Operating time to bowl improve the heat dissipation from the pis- 200 ton bowl and rim. An effective way of doing this is to position the cooling gal- 0 lery higher up and thus close to the bowl Series Modiﬁed bowl edge rim and top ring. The cooling effect at the ❸ Operating time to bowl edge crack of highly stressed series pistons (four test series, yellow bars) and Du- bowl rim and first ring grove is thus rabowl pistons – they showed no cracks at the end of the tests (four test series, blue bars)

44 www.autotechreview.com ❹ High-strength Monosteel design with effective cooling; it also offers the ❺ Optimised LVD Monosteel design with advanced cooling, and the option to possibility to combine cost optimised material with high-performance material combine different steel grades for the top and bottom

than Al pistons, given the same combus- of scaling is effectively reduced. tion process. Depending on the calibration In terms of thermodynamics, the and boundary conditions this temperature higher temperature level of steel pistons is increase can also be higher. a potential benefit. Also, a steel piston Starting from a combustion chamber assembly can be designed with lower temperature of 420 °C as a reference, the compression height, 6. This can either be higher temperature can even take heat- utilised to build an engine with lower treated steel to the limit of durability: at a total height or to use longer con rods to level above 520 °C, scaling begins to bring down the lateral force. Assembly occur, which can lead to crack formation. weight can potentially achieve same or The higher temperature level also means even lower level than comparable Al that the gallery will be hotter, which can assemblies. Measurements have shown a cause the oil to crack. Carbon that results power increase of around 2.5 % with the from this coking process can be deposited same calibration as a result of above men- ❻ Compact design and low compression height po- in the gallery, where the building up layer tioned advantages. This can be directly tential facilitated by using steel instead of Al allow up would impact cooling. Calculations have translated into 2.5 % better fuel economy, to 30 % lower compression height shown that this effect can increase the which in turn reduces CO2 emissions by bowl temperature by 45 to 80 K. the same amount. To overcome these challenges, Fed- charged passenger car diesel engine with eral-Mogul utilised its Monosteel truck 93 kW/l of specific output illustrates that piston technology, 4, and adapts it to SUMMARY AND CONCLUSION Al continues to offer potential. Neverthe- the special requirements of extreme pas- less, steel will be instrumental to solu- senger car applications. One modification Al and steel have different advantages to tions for even higher ignition pressures. is to maximise the gallery geometry as offer for piston development. Therefore, If the ignition pressure level should con- this ensures a sufficient oil flow. 5 the material choice has to be made for tinue to rise in high-end applications, the shows a steel piston design with a raised each individual engine and its set of resulting requirements to structural gallery and low material thicknesses development requirements. Piston cool- strength can be met with steel pistons. between crown and gallery, and between ing, for instance, is essential for both sys- Federal-Mogul will continue to advance grooves and gallery. If necessary, this tems and has to be optimised and con- both materials and related design options design element can be combined with a trolled for each application individually. along with the processes. hybrid piston construction that combines An Al piston with optimised design, com- dissimilar steel qualities via a suitable ing from an optimised manufacturing pro- welding process. For extreme applica- cess, can withstand the same thermal and tions, higher-grade steel can be used for mechanical loads as a steel piston. The the crown, while a regular steel quality is technology of local reinforcement contrib- used for the skirt. Protective coatings can utes to this. further improve the temperature resist- The Federal-Mogul Al piston devel- Read this article on ance. Applied to a steel piston, the level oped and manufactured for a highly www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 45 technology ALTERNATIVE DRIVES GREATER EFFICIENCY THANKS TO MILD HYBRID INTEGRATED APPROACH

A holistic approach opens up new opportunities to increase the efficiency of vehicles with combustion engines. In the Gasoline Technology Car (GTC) joint project, Continental and Schaeffler demonstrate that mild hybridisation with a high degree of functional integration can bring about additional efficiency gains due to the associated synergy effect.

46 www.autotechreview.com Authors TWO-WAY USE OF GREATER EFFICIENCY THANKS TO INDIVIDUAL COMPONENTS Future vehicle generations will need to be even more fuel-efficient than they are MILD HYBRID INTEGRATED APPROACH today. This is the only way that the fleet CO2 emissions target of 95 g/km (2020- FRIEDRICH GRAF is Director of Development 21) and the Euro 6c emissions standard Technology and Innovation, Division (2017-18) can be achieved. In order to Powertrain, Continental AG, demonstrate further potential for Regensburg (Germany). improvement, Continental and Schaeffler worked together to develop the Gasoline Technology Car (GTC) prototype, which was presented for the first time at the International Vienna Motor Symposium [1]. The GTC shows that it is possible to make advances in fuel consumption, THOMAS KNORR is Technology and Innovation even when measured against a very effi- Project Manager, Division cient reference vehicle. Powertrain, Continental AG, The wide range of modules that make Regensburg (Germany). up the GTC include down-speeding, thermal management, exhaust gas management, optimised combustion, and 48 V electrification. The integrated approach relies very heavily on close interconnection and comprehensive system optimisation of the components and functions SVEN HAGER is GTC Project Manager, Schaeffler integrated into the vehicle. AG, Herzogenaurach (Germany). In particular, the approach exploits potential based on the two-way use of individual components. The basic principle is that the whole of the GTC is greater than the sum of its parts. In abstract terms, this translates into the formula “1+1=3”. This way, the GTC MARKUS KNEISSLER saves 17 % more fuel in the consump- is Head of Development tion cycle than the reference vehicle. Automated Clutches, Schaeffler AG, Bühl (Germany).

THE BASIC VEHICLE AND ITS MODIFICATIONS

A C segment vehicle is used as the basis for the GTC joint project. The vehicle model selected, which is also used as the reference vehicle, has the following features: a three-cylinder DI gasoline engine with 1 l of displacement is used to motorise the vehicle (Ford Focus EcoBoost) weighing approximately 1.3 t (metric tonne). This downsized aggregate was chosen as “Engine of the Year” in 2012 and 2013 for its efficiency. Equipped with an exhaust gas turbocharger from Con- tinental, the standard version of this engine produces 92 kW and complies with the Euro 5 emission standard.

autotechreview October 2014 Volume 3 | Issue 10 47 technology ALTERNATIVE DRIVES

power, the range of possible operating states, and exhaust gas aftertreatment.

ELECTRIFICATION IN THE GTC INTEGRATED APPROACH

Electrification provides another crucial functionality in order to improve efficiency in the GTC. The 48 V Eco Drive System was integrated as mild hybridisation, according to a strict design-to-cost principle, 2. During installation, the original alternator in the basic vehicle was replaced with a 48 V electric motor (starter generator) with peak performance of 14 kW that is connected via a modified belt drive complete with decoupling belt tensioner from Schaeffler integrated into the electric motor. ❶ Overview of additional technologies and functions in the GTC An additional 48 V Li-ion battery with 10 Ah capacity stores recuperation energy. The electrical energy flows between volt- In the relevant version with a 12 V improve vibration isolation performance. age levels of 12 and 48 V are realised via start/stop function (micro hybrid), the ref- An electro-hydraulic clutch actuator a DC/DC converter with output of 3 kW. erence vehicle produces CO2 emissions of allows for new operating strategies, even This 48 V Eco Drive System enables just 114 g/km (combined) in the New in combination with manual transmis- almost weight-neutral mild hybridisation European Driving Cycle (NEDC). This effi- sions. The use of these strategies is sup- if there is no starter and the 12 V battery ciency is the starting point for the GTC. ported by a thermal management system is made smaller. The 48 V Li-ion battery is Power is transmitted via a six-speed man- in order to control energy flows in the also used as a second independent energy ual transmission in the basic vehicle and coolant in accordance with needs. source in order to ensure the on-board in the GTC. As a system integrator, Continental power supply is provided with energy A number of improvements were contributed the new injection system, when coasting, for example. made, when converting the basic vehicle engine control unit, operating strategy, 48 The recuperation energy facilitates key into the GTC, (1). Several components are V Eco Drive System, and an electrically functions in the GTC. These include the provided by Schaeffler: in order to facili- heatable catalytic converter from Emitec. provision of electric support to the com- tate down-speeding, for example, a dual- These components helped to optimise the bustion engine at lower speed ranges mass flywheel uses centrifugal force to combustion engine, the transmission of (e-boosting). In combination with the dual-mass flywheel, the three-cylinder gasoline engine with 1 l displacement has been made convenient to drive without suspension of momentum, despite the modified operating strategy with a con- sistently optimised ignition angle. This means the driver can use the gear shifting recommendations integrated into the vehicle in order to reduce the rotational speed without having to put up with significantly deteriorated response behaviour with a so-called “turbo lag”.

ELECTRIFIED CLUTCH

An electrified clutch (e-clutch) with hydrostatic actuation is integrated in the GTC, 3. This technology from Schaeffler ❷ Mild hybridisation in the GTC is based on the 48-V Eco Drive System makes functions usually found only in

48 www.autotechreview.com automatic vehicles possible for manual which uses electricity to attain its working standard and future cycles (WLTC, RDE) transmissions as well. These include temperature faster in cold starts. with more dynamic processes. the automatic creep function in traffic A cooled, low-pressure exhaust gas jams and when parking, as well as recirculation (EGR) system has also been easier handling of the engine start/stop INJECTION AND EGR integrated, together with an oxygen sen- system, passive coasting and further sor in the intake manifold. A physical hybrid functions [2]. While the basic engine remained the model of the air path allows the EGR to The option to disconnect the combus- same, injection technology with XL3.1 be regulated in real time in such a way tion engine from the powertrain at times injectors was installed, which is more pre- that high EGR rates of up to 15 % can be is used for energy-saving coasting (= no cise than in the basic vehicle. These injec- obtained in the GTC, without misfires. In load requested via the accelerator pedal) tors operate at an injection pressure of up a tip out event, the physical model allows in the GTC. The combustion engine is to 200 bar and are run on a GHP2 gaso- the EGR rate to be rapidly restored. These separated from the powertrain, which line high-pressure pump. These injectors high EGR rates combined with high loads reduces friction losses in the rolling vehi- yield particular benefits thanks to their help to optimise the centre of combustion cle and means that more energy is availa- accuracy, even when handling small vol- mass and save fuel as a result. ble for recovery if the driver brakes then. umes. In combination with corresponding Overall, the GTC can recuperate much control functions, the required jet prepara- more energy in the NEDC than the on- tion and propagation in the XL3.1 injec- THERMAL MANAGEMENT AND board power supply requires. This energy tors can be precisely adapted to a wide FRICTION OPTIMISATION facilitates other efficiency-enhancing range of conditions in the combustion measures. One example is the electrically chamber. This creates improved starting A modification to the split cooling archi- heatable catalytic converter (2 kW), conditions with regard to the Euro 6c tecture in the basic vehicle with a Schaef-

❸ The electric clutch (e-clutch) in the GTC is activated hydrostatically and enables hybrid drive strategies such as coasting with a manual transmission

❹ The thermal management module with a rotary slide value optimises hybrid operating strategies autotechreview October 2014 Volume 3 | Issue 10 49 technology ALTERNATIVE DRIVES

Euro 5 Euro 6c

Reference vehicle Gasoline Technology Car

Gasoline engine with turbocharger Hybridisation and start/stop - 7.0 %

CO2 emission: 114 g/km Downspeeding Thermal management - 4.5 % Exhaust Combustion - 1.0 % management optimisation - 1.5 % - 0.5 %

CO2 reduction through addition of the individual technologies: - 14.5 %

1 + 1 = 3: Additional CO2 reduction through synergy effects in the thermal system and between hybridisation and downspeeding: - 2.5 % ❺ Breakdown of individual contributions to improving CO reduction in comparison to the reference vehicle: - 17.0 % 2 efficiency in the GTC on the basis of measured values calculated on CO emission: < 95 g/km 2 the rolling road tester

fler rotary slide valve facilitates additional manage the combustion engine and the driving conditions on the road. Since the intelligent thermal management in the complete, complex control of mild hybrid integrated approach in the GTC joint pro- GTC, 4. Its purpose is to master the chal- components as well, including the operat- ject emerged from a design-to-cost princi- lenges posed by innovative hybrid drive ing strategy. This engine control unit ple, it may also help to further promote strategies. For example, the engine block already pre-empts the forthcoming EMS 3 the optimisation of the combustion engine can be temporarily decoupled from the strategy, in which an open Autosar-based powertrain and allow for it to be electri- coolant cycle in order to attain the system architecture can flexibly support fied in larger quantities. required temperature more quickly or to various system partitioning schemes and retain its temperature for longer. This electronic topologies in conjunction with References allows the engine to be restarted with low hybridisation and electrification. [1] Schöppe, D. et al.: Hubraumreduzierter Ver- brennungsmotor und 48 V Eco Drive – Ein integri- emissions following an idle phase. The erter Ansatz zur ganzheitlichen Effizienzsteigerung rapid heat-up reduces engine friction des Antriebsstrangs [Downsized combustion en- losses more quickly, which enhances effi- TESTING RESULTS, SUMMARY gine and 48-volt Eco Drive – An integrated approach to improve overall powertrain efficiency]. ciency. Friction-optimised components fol- AND OUTLOOK 35th International Vienna Motor Symposium, 2014 low the same strategy. For example, [2] Müller, B.; Rathke, G.; Grethel, M.; Man, L.: coated bucket tappets in the valve train The GTC is the result of a holistic Weniger Komplexität, mehr Funktionalität [Less reduce performance loss within the approach: only the interconnection of complexity, more functionality]. 10th Schaeffler Colloquium, 2014 engine. measures offers new degrees of freedom Thermal management is a fast-acting to develop operating strategies and opti- system that makes it possible to bring the mise the combustion engine powertrain. engine close to its limit temperatures, All in all, the described measures in the Thanks meaning the combustion engine can be GTC lower fuel consumption and there- operated at maximum efficiency. Higher fore CO2 emissions by around 17 %, exhaust gas temperatures, for example, when measured against the reference Professor Peter Gutzmer, Member of the are beneficial to exhaust gas aftertreat- vehicle with 114 g CO2/km in the NEDC, Executive Board, Research and Development, ment. Normal measures such as held 5. As such, the GTC even comes in Schaeffler AG, Herzogenaurach (Germany), and reserves and enriched combustion for slightly below the specification of 95 g Dr. Detlev Schöppe, Head of Engine Systems cooling purposes (component protection) CO2/km. At the same time, the project Development, Division Powertrain, Continental can be reduced. shows that a downsized three-cylinder AG, Regensburg (Germany), also contributed to gasoline engine combined with suitable this article. electrification is better to drive. ENGINE CONTROL UNIT This, in turn, is an important prerequi- site in order to motivate drivers of vehi- The close-to-series-production engine con- cles with a manual transmission to exploit Read this article on trol unit used in the GTC is designed to the potential of their vehicles under real www.autotechreview.com

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IATIA FULL PAGE Ad_Oct'14.indd 1 29-09-2014 11:18:51 technology BATTERIES BATTERY SHOW VOTES IN FAVOUR OF A LITHIUM-ION FUTURE

Early September, luxury electric automaker, Tesla Motors Inc, broke ground of a Gigafactory in the state of Ne- vada, US, to produce lithium-ion batteries for 500,000 vehicles by 2020. While researchers continue to experi- ment with different new materials and chemistries, lithium-ion continues to be the answer for most EV manufacturers globally. Auto Tech Review attended the Battery Show in Novi, Michigan recently, where experts believed the future belongs to lithium-ion, in the near-term at least.

INTRODUCTION parison of fiscal incentive policy for BRIGHT FUTURE FOR LITHIUM-ION electric vehicles”, the report looks at EV Recent studies and estimates suggest good adoption in 11 major auto markets and The development of a battery market for times for the future of electric vehicles. the impact of fiscal policies on market the future generation was one of the pri- Sales of EVs globally have been doubling demand. A comparative study of EV ority subjects discussed at the Battery year-on-year, and although it constitutes a market shares in the 11 countries is Show in Novi, Michigan. Industry leaders fraction of total vehicles sales – account- highlighted in ❶. noted that the battery market continues to ing for less than one per cent of the auto The global vehicle industry recognises evolve at a frantic pace, and that there are market – the growth is promising enough the fact that for now lithium-ion is the enormous opportunities that lie in the for more vehicle manufacturers to intro- most-preferred battery solution for EVs. A area of energy storage as a whole. duce products in the market, even as study by analytics firm Frost & Sullivan Lithium-ion is an area of significant researchers continue to chase new realms predicts that the demand for lithium-ion importance, said Dr Prabhakar Patil, CEO of efficiency. batteries will increase dramatically to an of LG Chem Power. It is understood that A report by the International Council estimated market-earned revenues of $ traditional chemistries would continue to on Clean Transportation (ICCT) released 7.60 bn in 2020, from the current num- be used and adopted worldwide, but in May this year states that tax exemp- bers of $ 381.9 mn. among all other chemistries being talked tions and subsidies are clearly playing a At the Battery Show in Novi, Michigan, about currently, lithium-ion is the real key role in spurring EV markets. Titled most estimates pointed towards a similar area of substantial growth. “Driving Electrification: A global com- outcome by the turn of this decade. Nonetheless, the biggest challenge for

52 www.autotechreview.com EV makers globally is the high cost of lithium-ion batteries. Manufacturers acknowledge the fact that overall EV costs would come down once lithium-ion batteries become more affordable to them, and that would happen with increased production. In this context, Tesla Motors Inc’s Gigafactory in Nevada holds particular significance, even as others continue to build more capacity. In his presentation, Vishal Sapru of Frost & Sullivan predicted that lithium-ion technologies would overtake the use of lead-iron in the battery sector by 2020. This would primarily be driven by greater uptake in grid storage, military and aero- space applications and the automotive sector. He expects future developments in China, Japan and South Korea to drive 1 A comparative study of EV market shares in 11 countries by ICCT this growth, while on-going projects in Germany, US and UK would continue to be the hotspots. To make lithium-ion by Wolfgang Bernhart, Senior Partner, said raw materials make up just 10 % of competitive and acceptable at a mass Roland Berger Strategy Consultants total costs, but they remain extremely crit- scale, costs would have to fall below $ GmbH, who noted that lithium-ion was ical. Improvements in cell component and 300/kWh, Sapru stated. likely to lead the way over the next dec- manufacturing costs account for around Nick Karditas, Director of Engineering, ade, particularly in the vehicle sector. 90 % of total battery costs, he said. R&D Bosch Battery Systems agreed and constitutes the other big cost factor for expected energy density to more than battery manufacturers globally. double by the end of the decade. Costs THE COST DISADVANTAGE are predicted to fall from $ 450/kWh today to $ 240/kWh by 2020, he said. As discussed earlier in this report, raw CONCLUSION Another interesting aspect touched material cost will likely dictate solutions upon by Sapru was that of development of for the future. A panel during the open- Widespread adoption of EVs worldwide smart cities, especially in Europe and ing session of the show said the success would hinge upon developments in the North America. One prime example of a of lithium-ion batteries would depend areas of safety, performance and costs. In smart city is the Yokohama Smart City Pro- on the economic viability of new the area of batteries, manufacturers are ject (YSCP) in Japan, which envisages technologies. weighing varied options, including introduction of 2,000 EVs to further reduce Kamen Nechev, Chief Technology advanced lead-acid, lithium-air, nickel- carbon emissions produced from transpor- Officer, SAFT Group said the prices of iron, lithium-sulphur and flow batteries. tation. The new Indian government too raw materials used in lithium-ion batter- However, lithium-ion continues to be the has earmarked a significant amount for ies – graphite, lithium and cobalt – are favoured chemistry for most manufactur- setting up 100 such smart cities in the currently not controlled by the battery ers. General Motors, for instance, is also country, details of which are yet to emerge. market. As demand from the battery talking about introducing the next wave A similar view was also put forward market grows, new sources of raw mate- of lithium-ion battery technology that will be offer improvements in safety and security, lifecycle, cost and also strike an efficient balance between utility and performance. Overall, experts voiced a strong need for standardisation of battery technology, a move that is likely to help achieve economies of scale.

Text & Photo: Deepangshu Dev Sarmah

rials will be needed to prevent price volatility and fluctuation. Nick Karditas, Director of Read this article on Engineering, Bosch Battery Systems www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 53 technology VW POLO GT VOLKSWAGEN POLO GT – ALL-ROUND FUNCTIONAL capability

Volkswagen India recently launched the new Polo, which we reviewed in our last issue and were quite impressed with the improvements made to it. Now it was only a matter of time that the GT versions came out wearing new changes. We were invited by the company to drive the petrol and diesel Polo GT in the scenic surroundings of Amby Valley and on a makeshift circuit on an airstrip. Here, we discuss the technical changes brought in by the GT variants.

POWERTRAIN aluminium keeps the engine weight low dling circuit, it required some coping up and aids performance and efficiency. with sudden drop in speed, while The GT variant is mostly about the power- The engine is smooth right from the manoeuvring tight turns. The lag though train and the performance it packs under start and through the rev band, with is only for a fraction of a second and can the hood. Disappointingly for many some harshness creeping in only at the be perceived only when pushing the car enthusiasts, powertrain combination stays edge of the red line. Since the turbo to its limits, in places such as a track. the same for the GT TSI, with a petrol 1.2 spools in from just about 1,200 rpm, Another fact that might be disliked by l TSI engine paired to a 7-speed DSG there is almost no conceivable lag during some is the clutch protector of the DSG, transmission. The old 1.6 l TDI unit driving. In a performance-focussed car which leads to a slow start off the block, though has been replaced by the new 1.5 with top quality hardware, the exhaust an issue more evident on the track. l TDI unit from the facelifted Polo but has left us wanting for more. Next up was the Polo GT TDI, with a been tuned to develop the output of the The DSG transmission sends the 1.5 l turbo unit, paired to a five-speed old motor at 103 hp and 250 Nm of power to the front wheels in a quick manual transmission. With weight-reduc- torque. The 1.2 l TSI engine too develops and responsive manner. In sports and tion being a key engineering target these about 103 hp, while torque is rated at 175 manual mode, the unit holds on to days, the engine features an aluminium Nm. The high output has been made pos- higher rpm and is eager to downshift cylinder head. sible by using turbocharging and direct multiple ratios, if required. An interesting fact about this engine is injection, which at the same time allows While in normal city runs, the trans- its bore and stroke, which stand at 77 x for lower displacement. Prominent use of mission is pretty responsive, on the han- 80.5 mm, leading to an almost square

54 www.autotechreview.com ratio. This was done because VW engineers realised that friction losses are prone to occur at cylinder liners. It’s widely known that oversquare engines develop more power at higher rpm, while undersquare engines develop more torque at lower rpm. A square ratio hence is claimed to offer a good balance between both and reduce frictional losses as well. The engine has a sufficient low-end torque and responds well to throttle inputs with power surging in freely till about 4,000 rpm. The engine is mated to a five-speed transmission, the gear ratios of which are well-sorted and should make A stiffer suspension setup could help exploit more from the capable chassis of the Polo GT it easy to live with the car in dense traffic. One thing that could bother some people is the long travel of the clutch, which is more evident understeer on the diesel ver- 19.9 km/l for the TDI version. compensated to some extent by its soft- sion (heavier weight upfront) being the ness. Gear shifting is easy and precise key differentiator. The short wheelbase with an acceptable travel distance. NVH and an agile chassis make for a dynamic ROUND-UP levels are appreciable and on the move, driving experience even in the wet, be it the cabin is well-insulated from such dis- on twisty mountain roads or a track. The The Polo GT has a distinct positioning in turbances. Only during hard acceleration, body-roll though creeps in at high speeds the Indian market, which goes a long way the diesel clatter becomes quite notable. and can be a tad unsettling at times, in acting as an advantage. From a techni- Although the GT TSI is technically bet- when coupled with some understeer. cal perspective, both variants perform ter equipped due to the addition of the What makes up for it partially is the impressively. But considering the cost, it DSG transmission to its specs, the GT TDI impressive grip from the new Apollo misses out on a distinctive styling. Priced turned out to be repeatedly quicker on the Alnac tyres, which performed well on a at ` 7.99 lakh, ex-showroom, Delhi, both track. This could be down partially to the soaking track too. The overall noise per- the GT variants seem to be priced high. At fact that the TSI unit mostly pulled off formance of these tyres is acceptable and the same time though, they offer from a slow start due its clutch protector. is a definite step forward. unmatched performance credentials in Also, the manual transmission on the TDI While the GT TSI offers more conveni- their segment. means the only lag during shifting is in ence and the smoothness of a petrol terms of driver input. engine, the GT TDI in our opinion is the (The complete review of the Polo GT can better pick from a value perspective. The be read on our website) GT TDI in all conditions felt to be a bit HANDLING quicker than the TSI and holds an advan- Text: Arpit Mahendra tage in terms of being significantly Photo: Bharat Bhushan Upadhyay Dynamically, the GT twins respond in a quicker off the line. ARAI-certified fuel- largely similar manner, with a slightly efficiency for the TSI is 17.2 km/l and Read this article on www.autotechreview.com

1.2 l TSI unit is a refined unit and responds well to quick inputs at most times The 1.6 l TDI unit with manual gears may seem conventional but felt quicker autotechreview October 2014 Volume 3 | Issue 10 55 SHOPFLOOR CONTINENTAL CONTINENTAL AUTOMOTIVE – Aiming MARKET-SPECIFIC LOCALISATION

INTRODUCTION including Passive Safety and Sensorics line also being the same. This standardi- (PSS), Engine Systems and Body and sation comes in handy for the transfer of Part of Continental AG, one of the world's Security. The manufacturing area is knowledge between plants manufacturing top five automotive parts suppliers, Conti- spread over 3,200 sq m, with a warehouse similar components and products. nental Automotive Components (India), behind the production facility. The facility has three lines, all of which has been steadily growing its presence in have similar configuration and support the the Indian market since its entry in 2008. production of leaded, as well as lead-free In the company’s Bangalore facility, PRODUCTION OVERVIEW components. The main advantage of lines printed circuit boards (PCB) are manufac- with similar configurations is that it leads tured and sent to its sister location in Continental said a core focus area for it is to high flexibility, while manufacturing. Manesar, where it is assembled. The PCBs standardisation of its components. One One example of the flexibility in manufac- are manufactured in what is called the method that the company employs to turing would be that when one line is front-end of the facility, while the back- achieve standardisation is by using the fully loaded, the product can be shifted to end takes care of all the assembly work. same equipments for the manufacturing a different line without much modifica- PCBs manufactured at the facility cater to process across all its facilities. The equip- tion. However, the company said this can all the business units of the company. ment to manufacture a certain component only be done after receiving approval from The facility undertakes manufacturing across various global manufacturing the customer, whose product is being components of other business units plants is similar, with the manufacturing worked on at that particular time.

56 www.autotechreview.com Continental Automotive Components’ (India) manufacturing plant in Bangalore undertakes the production of CONTINENTAL AUTOMOTIVE – Aiming components for the instrument cluster and electronic control unit (ECU) business units. It is the competency centre for the company’s electronics manufacturing for India. We visited this Bangalore facility to better under- MARKET-SPECIFIC LOCALISATION stand the way the foundation for operation of complex electronics is made.

The Indian automotive industry has between two and 65 s, depending on the very similar to that of screen printing, and small batch sizes, when compared to components on the board. The company includes a stencil with holes in it, which other countries, mainly due to the many uses surface-mount technology (SMT) in brings out a print on the circuit board. variants available in the market. This, in the process of manufacturing PCBs and The paste application step is an impor- turn, leads to Continental manufacturing manufactures about 225,000 to 250,000 tant one, as it includes two important pro- components for Indian customers in rela- PCBs per month, depending on the cesses within SMT. The first process is to tively small batch sizes, when compared requirement. Currently, all the electronics, ensure the exact amount of paste to be to that being exported. as well as the boards themselves are applied on the PCB, and the second is to imported, and only certain mechanical ensure that there is optimal paste volume components, like connectors, plastics, die- in the machine. These two processes of PCB MANUFACTURING PROCESS cast components and stamped products SMT are carried out with the help of a 3D are localised. optical measuring system that checks the This facility takes up the manufacture of The first step in the manufacture of area, distance and volume of the paste. PCBs for a wide variety of operations and PCBs is the application of bar code labels, The next area in the manufacture of draws its computer programme from a which ensures the traceability of the com- PCBs is in the placement of components common server. Continental manufactures ponent. The second process is a critical on the circuit board. Three machines PCBs of various sizes, for which the man- step, which consists of the first paste combined together place about 6,000 to ufacturing time may range anywhere application of the PCB. This process is 6,500 components per hour, the company

autotechreview October 2014 Volume 3 | Issue 10 57 SHOPFLOOR CONTINENTAL

noted. The next process takes up the duty through stress testing, to reduce chances of soldering the PCB and the components of any failure during operation, the com- together, where the paste that was earlier pany observed. The stress testing lasts for applied is heated to a pre-fixed tempera- about 20 minutes, making sure all the ture and then joined. The terminals on components of the cluster are in good the board are soldered onto the surface of working order. the component, thus resulting in this The penultimate process, and consider- technology being called SMT. All the ably the most important one, is the cali- points are joined and soldered together at bration of the pointers in the instrument an optimal temperature to ensure the cor- cluster. This calibration process has no rect quality of the joint. manual involvement, with only an auto- The final process in PCB production is mated camera giving the necessary com- the automatic optical inspection (AOI), mands and then ensuring that settings are which makes sure that the components made accordingly. The last process have been placed correctly and haven’t includes packaging and final labelling of moved away from their required position. the product. While the calibration This inspection machine also needs to machine for this process was imported ensure that the polarity of the component from Germany, the company has now is maintained correctly, for the right per- built this calibration machine in-house. formance of the product.

PSS ASSEMBLING PROCESS ASSEMBLY OF PCBS ONTO AN INSTRUMENT CLUSTER PSS systems like the ECU for the power steering unit are manufactured at the In the assembly process, the first step facility. First, the components are sol- includes mounting of the stepper motor, dered, like in the previous products, and which is required to drive the pointers on are then passed through an in-line AOI for the meters. These pointers sport LEDs, controlling the quality of the product. which are very bright to the naked eye, This product is then coated with a special necessitating the next step of applying a material, in a process called conformal diffuser onto the LEDs. This second pro- coating, which prevents moisture from There's a strong focus on testing, which takes place at cess also includes the assembly of the getting on to the board, following which multiple points on the line LCD on to the brackets. Here too, the the product is cured in an oven. company said, the LCD is imported, while The next process involves the auto- all the plastics and other mechanical com- matic tightening of screws in the product and then it is brought down to the ambi- ponents are completely localised. to a prescribed level. The cover of the ent temperature for a final test. Once all Thereon, the dials are mounted on the ECU is then clinched on by using heat these processes are complete, an auto- instrument cluster, followed by basic through an automated process. The prod- matic system-generated label is applied to checks and installation of the pointers on uct is first tested at the temperature of the the product, with the complete manufac- the component. The cluster is then put cover clinching, which is about 85° C, turing history attached to it digitally.

The Bangalore facility produces about 250,000 PCBs per month, subject to demand Human-intervention is low, owing to high automation

58 www.autotechreview.com TESTING

All products manufactured in the facility are put through testing in order to maintain error-free supply of components. For PCBs, there is a method of testing known as In-Circuit Testing (ICT), which is a board-level testing using a common machine for all products. The only change that is needed for validating different products is in the form of fixtures, which are suited to each product. This machine uses an optic fibre system that is connected to test pins on the board, for testing the components. The machine also has a system to ensure that all the products are tested, since the boards have to be mounted manually, which may be missed at times. This fool-proof system writes into the microcontroller when a component is tested, which is then checked at the next testing station before carrying out further testing. Failure of a process during testing will throw up an alert at the next testing Single Pin Insertion will replace the soldering of connectors onto the board eventually station, as well as at the back-end of the system, the company said. The testing rig also has the capability process, pins are mounted onto the PCB FUTURE TRENDS AND PLANS of testing different colours of LED lights. assembly one at a time, which will form The machine monitors the true colour, the connectors on the board. This method The company sees technologies like col- wavelength and intensity to identify the measures the force and the depth of inser- our-changing LED lights, improvements in colour of an LED light, even if it has been tion of the pin, making it a better process LCDs and similar technologies coming labelled wrongly. than soldering, Continental said. into the Indian automotive segment. Continental believes in setting-up dif- Although a lot of technologies can be ferent manufacturing line layouts for dif- incorporated into products, the company NEW TECHNOLOGIES, PROCESSES ferent batch sizes and different products. believes that the cost-conscious Indian It uses a process called SIPOC, which market may not be ready for them any Over a period of time, the company will stands for supplier, input, process, output time soon. replace the current method of soldering and customer, which involves everyone Continental noted that it is focusing connectors onto a board with a technol- involved with the line and then comes up heavily on localisation, which in terms of ogy called Single Pin Insertion. In this with a concept for the line. The manufac- software is already at a high level, but is turing line concept is first developed looking more into localising machinery through carton-box simulations, which and production lines. The company acts as a mock run of the layout of the believes that localisation will also directly line. The benefits of this process come in lead to reduction in costs, thereby benefit- the form of space and manpower optimi- ing customers. sation, and improved flow of the line. Another process being followed by the company is known as Design for Manufac- turing, where the company works with Text: Naveen Arul & Arpit Mahendra customers in the designing of components Photo: Continental to ensure their efficient production. This is something that is being done successfully off-late only, the company said. Continen- tal also follows a concept wherein a line is stopped, as soon as it reports three failures. The line is restarted only after it is checked Read this article on Cost-concious market will drive tech introductions and necessary rectifications are made. www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 59 NEW VEHICLE MARUTI SUZUKI CIAZ

MARUTI SUZUKI CIAZ – SETTING THE SEDAN GAMEPLAN ON TRACK

Maruti Suzuki India’s attempts to create a stronghold in the sedan space have yielded mixed results in the past. The Esteem was a successful product; the SX4 was moderately successful but the Baleno and Kizashi failed to excite even the most loyal of Maruti customers. While all these models were technically sound for their time, it was the overall packaging and perception leading to the mixed results. With the Ciaz though, the market leader is hoping to change all that. Does it deliver on the technical and packaging fronts, and more importantly, can it be a perception changer? We answer.

60 www.autotechreview.com The dynamics of the sedan market have with large air-dams in the bumper gives a PERFORMANCE changed a fair bit in India in the past few purposeful sense to the overall design. years, bringing about a sea-shift in the The roofline rises and tapers in sym- The Ciaz will be offered with two options way C-segment sedans are packaged. metry, without any sharp edges, going each for the engine and transmission – Maruti Suzuki’s SX4 has been struggling along well with the practical and luxuri- 1.4 l K14 VVT petrol and 1.3 l DDiS with to entice consumers in recent times, in the ous positioning of the vehicle. The alloy- a five-speed manual for both and a four- wake of much more modern and well- wheel design too helps impart a premium- speed automatic transmission for the pet- equipped products from the competition. look to the exterior, an attribute not usu- rol. During the drive, we were able to In a bid to grab a share of the popular ally seen on Maruti Suzuki cars. At the test only the manual transmission sedan segment, Maruti Suzuki recently rear, the design is a bit conflicting to the equipped vehicles. organised a drive preview of the new front and lacks a free-flow and integrated The 1.4 l K14 VVT engine is the same Ciaz. We drove both the petrol and diesel appeal. The rear bumper with two large unit found in the Ertiga, but certain modi- variants, and bring you this detailed scoops in the lower part leaves some fications and tuning have been incorpo- report from Jaipur. desire for improvement, when considering rated to improve the output. More impor- the overall design of the vehicle. tantly, these changes have improved the On the whole though, the Ciaz looks drivability and engine response. An out- STYLING better in flesh than in pictures, owing to put of about 90 hp might not sound much the small touches that lend it a premium but the Ciaz doesn’t disappoint, although The Ciaz has a commanding design, look. The design should appeal to a wider it isn’t one of the quickest in its segment. partly due to its pretty large exterior size, range of consumers than the company has The overall lightweight body, achieved which is reminiscent of the SX4 and the been able to target in the past. The fact due to a lightweight platform that lowers Kizashi. The car, however, has been built that the Ciaz comes across as a premium weight but enhances torsional rigidity, on an all-new platform and isn’t a mere offering on account of its exterior design, helps. The surprisingly light metrics of the derivative of the SX4 or Kizashi. The wide and fit & finish by segment standards – Ciaz at 1,010 kg for the petrol and 1,105 front grille along with swept back triangu- that have been upped in recent times – is kg for the diesel give it a good power-to- lar headlamps lends a wide and planted in itself an indicator of the progress made weight ratio. look to the front. The chrome grille along by the company. The petrol motor, however, isn’t as autotechreview October 2014 Volume 3 | Issue 10 61 NEW VEHICLE MARUTI SUZUKI CIAZ

segment, the benefits of which are evident at the rear seat. Legroom is more than what one would find in the Hyun- dai Verna or the Honda City, and in our opinion, generous headroom and shoul- der room make the seat the best option in its segment. A highlight of the cabin is the dash- board design and more so its fit and finish levels, and material quality. Maruti Suzuki has made a significant progress in this department and the Ciaz interiors feature a clean and ergonomically sound cabin. Touch-points are good to feel in most places and the 7-inch colour touch-screen in the centre console adds to the upmar- ket feel of the interiors. The screen in The 1.3 l DDiS engine is more refined than the petrol one and feels livelier to drive too itself though is a little slow to respond to inputs, but is intuitive. The steering wheel refined as expected and motor sound is rol variant comes across as more of a too feels premium to hold and offers easy- audible in the cabin, while accelerating value-focussed model and will find to-use audio controls. Seats on both ends or at high speeds. In addition, the gear acceptance subject to significantly under- are comfortable and feature material of ratios, which seem to have been spread cutting the key competitors in pricing. good quality and texture. out wide apart in favour of fuel-efficiency, make the engine gather speed a little slower. The gearbox in itself INTERIORS HANDLING though is smooth to operate and coupled with a light clutch, makes the car The Ciaz has the longest wheelbase in its Ciaz is a neutral-handling vehicle with a easy to drive in traffic. The abilities of the 1.3 l DDiS engine are well-known to all, owing to the multiple brands using it in their cars successfully. Still it came as a surprise to us that the diesel engine outperforms its petrol sibling in almost every area. The re-cali- brated unit now offers power lower in the power band, reducing lag and improving response time. The unit makes about 88 hp and 200 Nm of torque, the latter giving the car a more instantaneous thrust while accelerating. At about 1,600 rpm, the engine begins to respond and by 2,000 rpm acceleration is brisk. The diesel Ciaz also turned out to feature a quieter cabin than the petrol version and at highway speeds, it’s almost hard to make out if The busy-looking 16-inch alloy wheels along with a long wheelbase lend a good stance to the Ciaz there’s a diesel engine under the hood. Fuel-efficiency is claimed to be the highest in the country with the petrol returning 20.7 km/l and the diesel returning 26.2 km/l. This should turn out to be a significant marketing tool for the company, given its perceived strength in this area. In a nutshell, Maruti Suzuki seems to have got its engine options right, since the diesel version is expected to sell more and is also the better one. The pet- Overall built quality, of the Ciaz is impressive. Minimal panel gaps and neat contours highlight the progress

62 www.autotechreview.com good suspension set-up, which offers good ride quality over broken surfaces. This would be appreciated well by people looking for a practical and comfortable sedan. Going through bends at high speeds too doesn’t unnerve the driver as the car holds its line, owing to the 195-section tyres fitted on 16-inch wheels, the latter of which will be offered only on top variants. There is some body-roll but given the positioning of the vehicle and its compliant handling, there isn’t any- thing to complain about. Helping the dynamics is the lightweight design technology called Suzuki Total Effective Control Technology (STECT). This technology uses high ten- sile steel in the body structure, which reduces weight without compromising on rigidity and safety in turn. Despite being Impressive material quality and a clean & ergonomic layout makes this Maruti's best locally made interior yet the longest car in its segment with a rich list of features, the petrol Ciaz weighs 1,010 kg while the diesel version weighs released by the company yet. didn’t compete strongly with its European 1,105 kg. To put things into perspective, and Japanese rivals in this department the Honda City diesel weighs 1,125 kg, but that has changed with the Ciaz. Add while being smaller and having a lighter ROUND-UP to it the popularity of diesel engines in the aluminium engine head. The Ciaz body- segment and the appreciable performance in-white, in fact, alone weighs about 50 With the Ciaz, Maruti Suzuki has been of the unit in Ciaz, and it seems Maruti kg less than that of the SX4. successful in delivering an attribute yet Suzuki has a winner on hands. Given the Tyre options on the Ciaz include low- to be seen on locally-engineered prod- shifting preference towards petrol, owing resistance tyres from Apollo and Good- ucts – premium feel. The Ciaz, both on to the reducing gap between it and diesel, year, of which we found both to offer the outside and inside feels premium by the petrol model too is expected to play a respectable grip in wet but the Apollo segment standards and should be able much more important role than filling up seemed quieter on the highway. These to strike a chord with style-conscious a column on the brochure. low-resistance tyres also contribute con- consumers too. In the sedan segment, Maruti Suzuki siderably to the best-in-class fuel-effi- A major progress comes in the form of finally seems to have a product that can ciency claims by the company. The figures interior design and the quality offered take away a huge chunk of sales off com- for the same though haven’t been therein. Past products from the company petitors, and establish an acceptable equilibrium between the perception of premium and Maruti Suzuki. The only critical thing that now needs to be offered is competitive pricing, something the company has delivered well on, in the past. It is critical for the company to be successful with the Ciaz, as that would pave the way for upcoming platforms and models, opening up an untapped segment for the company.

Text: Arpit Mahendra Photo: Bharat Bhushan Upadhyay

Read this article on Ciaz offers neutral handling and impressive ride quality. The steering wheel is quick and offers decent feedback www.autotechreview.com autotechreview October 2014 Volume 3 | Issue 10 63 DECODING TECHNOLOGY

PISTONS & RINGS – PRIME MOVERS

A piston is used to compress oxygen and In diesel engines especially, steel pistons DR ARUN JAURA fuel, pressurise the mixture for combus- have a high potential for reducing CO2 tion to produce power. Pistons and rings emissions due to lesser frictional losses, Managing Director and Founder, TRAKTION Management Services have been of considerable focus and produce lower emissions and better fuel Private Limited (TRAKTION) development for engines. With the evo- economy. Interestingly, the lower com- lution of mobility and higher perfor- pression height of the steel piston can mance demands from engines, thermal make the engine smaller and provide loads have increased. In addition, engine better styling avenues in vehicles with a they need materials with high strength downsizing requirements have increased lower hood, approach angle and lower between 200-300 °C along with appro- mean and peak pressures, while high- coefficient of drag, resulting in better priate wear characteristics for operation speed concepts have imposed greater pedestrian crash safety and improved in normal and dry lubrication conditions. inertia forces. fuel economy. Other major factors are high thermal There has been a high pace in pis- Pistons come with high performance conductivity and thermal expansion. ton development for dedicated applica- coatings on the combustion face of the Corrosion resistance and resistance to tions through innovation in different piston and the skirt. These coatings pre- micro-welding are a must. materials, architectures, manufacturing vent heat loss through pistons, maintain Typical piston rings are manufactured processes, sizes and treatments to high combustion temperature, inhibit from cast iron and steel, and their perfor- increase durability and reduce friction carbon build-up, increase horsepower mance can be optimised by high quality – both in steel and aluminium. Each of and reduce heat transfer to the top ring. coatings. Manufacturers have rings these enablers has its own influence on coated with chromium ceramic, molyb- temperature tolerability, heat dissipa- denum, plasma filled, and with chro- tion, sensitivity and lowered clear- ROLE OF PISTONS RINGS mium nitride PVD. Coatings are done for ances, resulting in greater thrust and improving wear and reducing lubricating good wear characteristics. Piston rings could account for 22 to 26 oil consumption. % of total friction in an engine. Trade- offs between good sealing and long life- ALUMINIUM VS STEEL time have become evident due to this CONCLUSION high friction. The key functions of piston Aluminium-forged pistons are lighter due rings include sealing of the combustion Pistons and rings are the heart of an to thinner walls and conduct heat better, chamber, regulating engine oil consump- engine. With changing powertrain can meet higher cylinder pressure and tion and supporting heat transfer from requirements, stringent emissions norms temperature limits, and offer lower fric- the piston to cylinder. A four stroke and higher fuel economy demands, it is tion in iron block and liner engines. Cast engine has three rings and a two stroke prudent to stay in high gear of innovat- aluminium pistons are higher in cost, engine has two rings. The two at the top ing rings and pistons. heavier and require cooling oil flow due control oil and are primarily for com- to higher piston temperature. Cooling pression sealing, also architectures include oil-cooled gallery known as compression closer to the hotter regions, thus helping rings. The lower ring, with greater heat dissipation. known as the oil con- Steel pistons, on the other hand, have trol ring, scrapes oil better strength and are suited for higher from the cylinder walls peak cylinder pressures. Steel pistons are and plays a major role being used more for truck applications in managing oil and mid-size bore engines. With engines consumption. getting more compact and delivering Piston rings are sub- high power density, heat dissipation jected to dynamic requirements are higher and are sup- mechanical and tribo- posed to be better met with steel pistons. logical loads. As such,

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