Issue 1/2012

Porsche Engineering Magazine

Shift into gear for the future.

911 (Type 991): fuel consumption (in l/100 km) urban 12.8 · extra-urban 6.8 · combined 9.0; CO2 emissions 212 g/km

Issue 1/2012

Porsche Engineering Magazine

Use our drive.

911 (Type 991): fuel consumption (in l/100 km) combined 9.7-8.2; CO2 emissions 229-194 g/km About Porsche Engineering

About Porsche Engineering

At Porsche Engineering, engineers are ufacturer. Whether you need an auto- working on your behalf to come up motive developer for your project or with new and unusual ideas for vehi- prefer a specialist systems developer, cles and industrial products. At the re- we offer our customers both because quest of our customers we develop a Porsche Engineering works success - variety of solutions – ranging from the fully across both of these areas. The design of individual components and extensive knowledge of Porsche Engi- the layout of complex modules to the neering converges in Weissach – and planning and implementation of com- yet it is globally available, includ ing plete vehicles, including production at your company’s offices or produc- start-up management. What makes our tion fa cil ities. Regardless of where we services special is that they are based work – we always bring a part of Porsche on the expertise of a premium man - with us.

www.porsche-engineering.com

4 Porsche Engineering Magazine 1/2012 Editorial

Dear Readers,

When we analyze our company’s more recent projects, one increase operating distances without having to noticeably thing is clear: sustainability and environmental concerns compromise the comfort of the vehicle user. have changed demand behavior and have now become a driving force of technical innovation in many areas of In order to contribute actively to these developments for our automotive development. customers, we are continuously investing in our expertise and capacity at Porsche. Whether this is on a grand scale, Tighter political and legal regulations for the mobility of such as the consistent expansion of the Weissach Devel - tomorrow play an important role in this. It seems to us, opment Center, or on a smaller scale, such as the opera- however, that another important factor here is the con- tion start-up of new high-voltage and thermodynamics stantly changing values of customers. testing stands. This has a direct effect on clear trends in automotive devel - opment. We invite you – not without pride – to take a look at this and other Porsche developments: Discover for yourself how At the same time though, the “old economy” of automotive Porsche is setting new standards in the areas of efficiency, development, such as body construction and drive tech - lightweight construction, performance and emotions with nology, is experiencing another renaissance. Lightweight the latest generation of the 911 Carrera. construction has been an essential part of bodywork devel - opment for some time now. But the potential of combustion If reading our magazine awakens your interest in devel - engines has also still not been fully exhausted yet. oping something with us, then we look forward to working with you to meet the challenges you set us. The mobility of today and tomorrow is increasingly electric. With the hybridization of vehicles, we are experiencing a We hope you enjoy reading our first issue of 2012. highly complex step towards electromobility. There has already been plenty of hard work on the further develop- Yours, Malte Radmann and Dirk Lappe ment of battery and designs, in order to Managing Directors Porsche Engineering

911 (Type 991): fuel consumption (in l/100 km) combined 9.7-8.2; CO2 emissions 229-194 g/km Porsche Engineering Magazine 1/2012 5 Contents

Contents

News 8 About Porsche Engineering 4 Editorial 5 The new 911 Impressum 34 The most efficient and sportiest Next Up 35 Carrera ever 10

High voltage: 300 kW source/drain High-voltage and thermodynamics Cover test stand 19 We develop the future, for example the seven- Weissach is growing speed manual in the new 911. Shift Expansion at the Weissach into gear for the future with us – what will you use Development Center 22 our drive for?

Keeping cool in future Vehicle interior climate control in electromobility 24

Who developed it? Porsche. Special exhibition “80 Years of Engineering Services by Porsche” 28

Smoother starts using robotics Porsche Engineering clutch robot 30

6 Porsche Engineering Magazine 1/2012 Contents 10

Identity

The new 911: innovative, cutting-edge technology for new benchmarks in efficiency, perfor- mance, lightweight construction and emotions

19

Innovation

High-voltage and thermodynamics test stand for the development and testing of high-performance batteries

22 30

Analysis

Unique robot for the efficient testing of clutch charac - teristics in vehicles

Growth

Expansion of the Weissach Development Center for demanding customer projects

Porsche Engineering Magazine 1/2012 7 News

Wolfsburg: Porsche Engineering grows

Thanks to continuing growth, activities at Porsche Engineering in have been expanded. At the project office in Wolfsburg, there are not only special - ists in the development of electric/ electronic systems, but also first-class experts in the layout and development of modules, assemblies and complex com ponents. The Wolfsburg office plays an important role in Porsche’s projects for external customers and therefore contributes significantly to the inte grated engineering services within the corpo- rate group.

CURRENT NEWS

Porsche Engineering Prague: ten-year anniversary

Along with 80 years of Porsche engi- Milan Simadl, head of neering services, 2011 also marked the commercial section of the German Embassy the tenth anniversary of the Prague in the Czech Republic subsidiary of Porsche Engineering. and Dr. Milos Polásek,ˇˇ The branch office in the Czech Repub - head of Porsche Engi- lic is an integral part of engineering neering Prague, at the 10 year anniversary services by Porsche. It specializes in celebrations complex technical calculations and simulations, and has expertise that stretches way beyond the automo - tive industry to a wide range of areas and sectors. It was established after a the intensive and valueable collabo- results from scientific engineering re- successful partnership with the Tech - ration between the industry and dif- search are also channeled into Porsche nical University of Prague. Through ferent fields of science, the latest Engineering.

8 Porsche Engineering Magazine 1/2012 News

QUALITY

Awarded

Porsche Engineering Group GmbH has once again successfully com- pleted a quality management audit according to the industrial standard DIN EN ISO 9001:2008. The exter- nal auditor from the German Orga- nization for the Certification of Man - Historical analysis agement Systems (DQS) awarded the engineering services by Porsche Porsche Engineering has carried out a 1948, was technically way ahead of its a high standard of qual ity for its detailed breakdown, analysis and docu- time in many respects. By analyzing and projects. Amongst other aspects, mentation of the historical Type 360 examining the engine today, new data both the project management and “Cisitalia” engine on behalf of the Stutt- about the innovative technologies of the motivation of staff at the engi- gart-based Porsche Museum. The leg - the past can be gathered and a unique neering services by Porsche was endary Grand Prix racing car, completed piece of documentation for automobile assessed as “very good”. at the Porsche engineering office in enthusiasts will be created.

A Porsche to carry this material for bags came about corresponding marketing brochure,” through working on the material for the explains Heidi Zink, project engineer for in your hand soft-top of the Boxster Spyder and the the Boxster Spyder.

A Porsche for travel, a Porsche for din- The bags are available online at: www.porsche.com/shop ner and even a Porsche for the bath- room – rarely has the visual connection between the and Porsche Driver’s Selection products been so close. This attractive product series, of- ficially called “Porsche Travel System Soft Top Luggage”, is pure . It includes items such as travel cases and bags in various sizes, a hand- bag, as well as a washbag manufactu- red in the same original soft-top mate- rial that is used for the folding tops of Porsche Cabriolets. “The idea to utilize

Cutting-edge 911 technology

The most efficient and sportiest Carrera ever Identity shaping in three digits: the new 911

THIS MODEL HAS BEEN THE GOLD STANDARD IN ITS CLASS FOR GENERATIONS. BUT NOW THE 911 SETS THE BENCHMARKS IN PERFORMANCE AND EFFICIENCY EVEN HIGHER – DEMONSTRATING ONE HUNDRED PERCENT PURE PORSCHE INGENIOUS ENGINEERING. Cutting-edge 911 technology

Cutting-edge technology in every area

The new 911 Carrera embodies the competence, passion and technological expertise of Porsche more than any other model generation. Four key development aspects define the new 911: lightweight construction, performance, efficiency and emotions. Porsche Engineering has also played a significant part in creating the new generation of the 911 by developing the new seven-speed manual transmission.

With the new generation of the 911, like lightweight construction, perfor- engines in comparison to their output Porsche engineers have once again com - mance, efficiency and emotions are in- have always given the 911 Carrera an bined the latest technological develop- creasingly playing an equally important exceptional power-to-weight ratio and ments in an exceptional way, in order to role here as in the 911. exemplary fuel consumption. The new provide maximum driving pleasure and generation differentiates itself from the efficiency. This ingenious engineering Efficiency competition even further in both areas: is not just evident in the sports , with a power-to-weight ratio of 4.7 kilo- but also in a wide range of engineering Lightweight construction throughout grams per kW (10.3 lb per kW), the new projects for external customers. Aspects the vehicle and extremely economical 911 Carrera S clearly comes out top of

12 Porsche Engineering Magazine 1/2012 Cutting-edge 911 technology

its class. And in NEDC consumption, the 911 Carrera and the 911 Carrera S, each with Porsche Doppelkupplungs - getriebe (PDK), once again boast un- matched and exceptional figures, with 8.2 l/100 km (28.6 mpg imp.) and 8.7 l/100 km (27 mpg imp.) respectively.

This huge step forward rests on the design: the entire new 911 Carrera has been designed for more efficiency, mini- mized rolling resistance and optimized operating strategies. The main basis for this efficiency is lightweight construction. The completely new aluminum-steel con- The extremely impressive 911 Carrera and 911 Carrera S models are highly efficient with maximum performance struction of the body not only enables the new model to be up to 45 kilograms With the new 911 Carrera generation, was widened from 898 millime- (99 lbs) lighter than previous genera- Porsche has also further improved the ters to 1,137 millimeters. It is extended tions, but also ensures a weight advan - fine details of the previous generation’s automatically at 120 km/h (75 mph) and tage of more than 100 kilograms (220 exemplary aerodynamics. The basic build - retracted at 80 km/h (50 mph), but can lbs) over the lightest of competitors. ing blocks of the aerodynamic design also be extended below these speed are the streamlined body surface, the limits at the push of a button. Further The mechanical components of the en - new rear spoiler and the cooling system, aerodynamic improvements were se - gines have been made even more friction- which does not require large air intakes cured by optimized air brake spoilers, less, and to reduce consumption even underneath the vehicle, thereby enabling aerodynamically optimized exterior mir- more, vehicle electrical system recupera- the smoothest possible vehicle floor. The rors, improved engine ventilation and tion and a map-controlled coolant ther- aerodynamically effective area of the rear optimized fairings on the front wheels. mal management system have been added. Through innovations and corre- sponding improvements in these two Using the latest technology for more performance and efficiency areas, Porsche has succeeded in re - 1. Lightweight structures ducing consumption in the NEDC by 2. Low drag, variable 0.45 l/100 km (522.7 mpg imp.). The aerodynamics 1 3. Start/stop function, efficiency target has also been achieved coasting, on-board elec- 2 with the help of the first ever seven- trical system recuperation 3 4. Electro-mechanical speed transmission in automotive con- 5 6 4 7 5. Drive train incl. seven- struction and the Porsche Doppelkupp - speed PDK/world’s first lungsgetriebe (PDK), also with seven seven-speed MT 6. Engine technology speeds. Porsche Engineering led the de- 8 7. Thermal management of engine + transmission velopment of the manual seven-speed 9 8. Reduced residual braking transmission, working together with the torque 9. Reduced tire transmission manufacturer ZF Friedrichs - rolling resistance hafen AG (see info box on pages 14/15).

911 (Type 991): Fuel consumption (in l/100 km) combined 9.7-8.2; CO2 emissions 229-194 g/km Porsche Engineering Magazine 1/2012 13 Cutting-edge 911 technology

Ingenious Porsche Engineering The development of the new seven-speed manual transmission

Porsche Engineering led the development of the world’s first Shift pattern before conversion Shift pattern after conversion and only manual seven-speed transmission in the automotive sector, working together with the transmission manufacturer R 365 R 1357 ZF Friedrichshafen AG. The new transmission was based on the Porsche Doppelkupplungsgetriebe (PDK). Taking the man ual gear changes into consideration, the ratios of the third and seventh gears were modified in comparison with the PDK. The third gear has a higher ratio, which reduces consumption. The seventh gear has a lower ratio to maintain ➔ pulling power even at comparatively low speeds. R147 246 Shifting gears are not positioned directly opposite each other in the PDK Gears are shifted out via two cable winch mechanisms. One transmission, a completely new internal gear shift had to be cable is for selecting the gear and the other is for shifting it. developed. The goal here was to covert the shift pattern to The transmission uses an H-shaped shift pattern. As the an H-shaped shift pattern with a new internal gear shift. The man ual transmission is based on the PDK transmission, and mechanism that enables this conversion is based on an in- neighboring gears (for example first gear and second gear) vention by the company ZF Friedrichshafen AG.

The world’s first ever seven-speed manual transmission, developed by Porsche Engineering

14 Porsche Engineering Magazine 1/2012 Cutting-edge 911 technology

1. Fitted bolt 2. Cover plate 1 2 3 4 1 3. Flange bushing 2 4. Spring 5. Locking ring 3 6. Carrier shaft 4 5

6

Figure 1 Gate 3/4 selected ➔ Locking ring is decoupled from the carrier shaft by 1 mm

Through this invention, any gear arrangement in the gear set Figure 2 of the transmission can be converted into an H-shaped shift Gate 5/6 selected ➔ Carrier shaft pushes the locking ring upwards and blocks gate 7 pattern that is familiar and comprehensible for the driver. The main element of the gear shift is the carrier shaft, which Figure3 can move translationally (in a straight line) and rotationally Shift into fifth or sixth gear ➔ Carrier shaft rotates by 29° ➔ Locking ring moves back in axial direction (turning). The carrier shaft’s movement is transmitted to the and releases gate 7 cable winches outside it and transferred to the gears by the lever mechanism on the shift cover. In order to select a gear, Shifting out of fifth or sixth gear ➔ Carrier shaft rotates back to neutral position Locking ring is radially the carrier shaft is pushed axially in the shift gear frame. The ➔ pretensioned by the rotating spring carrier shaft is then turned in order to shift gears. The shift forks are linked to the individual shift gear frames via the Figure 4 shift rods. Through the unique arrangement of the shift fin- Shifting to gate 7 ➔ Carrier shaft pushes the locking ring upwards gers on the carrier shaft, the shift gear frames of each gear are moved at the same time through this rotation during the shift from first gear into second gear.

Seventh gear shift lock

In order to prevent inadvertently shifting to seventh gear, a special shift lock was developed. That means that it is only possible to change into the gate for seventh gear if fifth or sixth gear was selected beforehand. However, the driver can shift back down at any time.

Martin Kuhn

Porsche Engineering Magazine 1/2012 15 Cutting-edge 911 technology

In this way, like its forerunners, the new The second main reason for improved developed from scratch for the new 911 Carrera characteristically combines performance is the new drive unit. Both 911 Carrera. This also has a tangible ef- exciting sportiness with exemplary effi- engines, with 3.5 liters and 3.8 liters dis - fect on performance: When braking on ciency. The formula for this: Porsche In- placement, have been designed accord - road surfaces with different levels of telligent Performance. ing to motor racing principles for high grip, a tug on the steering wheel im- revs. The maximum engine speed of the parts a steering input in the desired di- Performance six-cylinder engines has been increased rection, making it easier for the driver by 300 rpm to 7,800 rpm. The entire in- to stabilize the vehicle and keep it in the The proof of the 911 Carrera’s perfor- take manifold has also been optimized. desired lane. mance gain speaks for itself: the new The intake air flows through flow-opti- 911 Carrera with optimal sporty equip- mized channels, new multi-hole injec- Another decisive contribution to the im- ment can lap the Nürburgring’s Nord- tors inject the fuel more efficiently and pressive increased performance of the schleife in 7:40 minutes – 14 seconds exhaust emissions exit the 911 Carrera new 911 Carrera is provided by the en - faster than the previous model. through a system with reduced back - tirely newly developed optional Porsche pressure. The fine-tuning of the aero- Dynamic Chassis Control (PDCC). The The overall design of the new 911 Car- dynamics has succeeded in reducing intelligent control of the PDCC system rera provides the foundation for this sig- the total lift (CA) of the new 911 Carrera is, for example, able to exercise indi - nificant improvement in performance. models by 0.02, to a mere 0.05. vidual control over the hydraulic actua- The lengthening of the wheelbase by tors, depending on the driving situation, 100 millimeters and the wider front Even more agility in the new 911 Carrera influencing self-steering behavior in the track width alone – 46 millimeters wider is provided by Porsche Torque Vectoring process and consequently improving in the 911 Carrera and 52 millimeters (PTV). This system consists of a mechan - vehicle stabilization. wider in the 911 Carrera S – results in ical limited-slip rear differential and vari- completely new vehicle geometry with able torque distribution to the rear axle. Lightweight construction even more driving stability at high speeds, when on the straight and when For the first time ever, Porsche has With the new 911 Carrera, Porsche sets cornering. used electro-mechanical power steering new standards in lightweight construc- tion. Up to 45 kilograms less total weight than the previous generation means a total weight reduction of 98 kilograms in the basic vehicle design. The reason for this difference: increased safety re- quirements, a longer wheelbase, fuel consumption reduction measures and a more powerful product firstly led to a weight increase of around 58 kilograms in comparison to the previous models.

The key to success was lightweight con- struction throughout the vehicle. For the first time in the new 911 Carrera, an alu- minum-steel body construction has been Porsche identity: the unmistakable performance of the new 911 used. The underlying idea of this design

16 Porsche Engineering Magazine 1/2012 Cutting-edge 911 technology

is using the right material in the right place. The extensive use of aluminum to reduce the vehicle’s weight is therefore The targeted use of a wide range of materials balanced with elements of steel of vary- has resulted in a signifi- ing degrees of strength for a more rigid cant reduction in weight body and optimum occupant protection. styling meant that the engineers were the sound. Mechanical engine sounds Parts that are especially important for faced with quite significant challenges. are characterized by higher frequencies passive safety, such as the inner roof Engineers at Porsche Engineering con- and have tonal elements. frame and the B-pillar, have been made tributed to the development and imple- in ultra high-strength, boron-alloyed mentation of the overall leather design The basis of the sound design for the air steels. The new modular roof design by designing the instrument cluster and intake and exhaust systems in the new also provides advantages in terms of the center console as well as the carpet- 911 Carrera was created in the very early weight. For the series model without a covered elements. Specifically, they were stages of the vehicle’s design. The lay- sliding roof, the steel outer skin of the responsible for creating a strategy for out and dimensions of the manifolds, roof has been replaced with significantly component and tolerance layout and pipes, catalytic converters and mufflers lighter aluminum. for carrying out covering tests. Manag - were all visually illustrated and evalu - ing system and component suppliers ated with the help of a computer model The drive train, chassis and electrical and cooperation with the Porsche leather before there was even any hardware. equipment have all also been compre- manufactory were also an important part hensively redesigned to be lighter. The of their job. The development of muffler systems is chassis accounts for more than five kilo- one of the core competencies at Porsche grams of weight reduction, mostly thanks The driving experience in the 911 is de- and is always carried out at the Weissach to the newly constructed front axle with fined by the design, the sound and the Development Center. In order to allow compact lightweight suspension strut. vehicle providing feedback from the the driver to feel the revs and the power road to the driver through shifting gears of the engine, the pathways of the air Emotions and revving the engine. The driver expe- intake and mechanical engine sounds riences real driving pleasure when he are tuned so that messages from the A highlight of the 911 design is the leather feels the performance of the vehicle di- new 911 to the driver are transmitted interior of the vehicle. Typical Porsche rectly. The main communicator of this is in as pure and unadulterated form as possible in all driving conditions.

Like no other sports car, the new 911 Carrera shows that by combining the latest cutting-edge technology, excep- tional performance and the highest effi- ciency can be achieved at the same time. Porsche engineers love the challenge of reaching ever higher levels of perfor- mance – whether in a sports car or in an external customer project. There’s a bit of 911 in all Porsche Engineering Porsche Engineering contributed to the development and implementation of the leather interior design projects.

Porsche Engineering Magazine 1/2012 17 Cutting-edge 911 technology

Out in the open The 911 Carrera Cabriolet debuts an innovative new roof design

The new open-top models of the 911 Carrera operates in the rear of the 911 Carrera Cabriolet, and its power and the 911 Carrera S also belong to the new is transmitted to the rear wheels by the seven-speed manual generation of the classic 911 sports car – the transmission. The open-top 911 Carrera S has a 3.8-liter open-air season can begin. six-cylinder engine with 294 kW (400 hp) and also comes with a seven-speed manual transmission as standard. The 911s also differentiate themselves strongly With its completely newly developed and unique roof de- from the competition in another way: in the NEDC both sign, the Cabriolet continues what the Coupé began with models consume less than ten liters of fuel for 100 kilome- its new aluminum-steel body. The typical 911 roof contours ters (23.5 mpg imp.). Alternatively, Porsche Doppelkupp - have been entirely preserved for the first time. Intelligent lungsgetriebe (PDK) can also be optionally selected for the lightweight construction, which also includes the use of Cabriolet models, which makes even lower fuel consumption for the construction of the convertible top, has and shorter acceleration times possible. ensured less weight and more sportiness, as well as lower consumption and greater comfort. Porsche has managed The longer wheelbase compared to the previous model, to reverse the weight spiral for all convertible 911s and has the wider front track at the front axle and the new electro- managed to make the new Cabriolet models significantly mechanical power steering give the new Cabriolets even lighter than their predecessors. sportier driving characteristics, more precision and increased agility. On top of that, additional active control systems are Both new Cabriolets have the same drive system as the available as standard or as an option depending on the model, Carrera Coupés. A 3.4-liter boxer engine with 257 kW (350 hp) which will improve driving dynamics even further.

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High-voltage and thermodynamics test stand

High voltage: 300 kW source/drain

The high-voltage battery is the heart of electric and hybrid vehicles. When developing high-voltage batteries, testing the battery with predefined profiles in both quadrants i.e. when charging and discharging requires special attention. Porsche Engineering has developed a special high-voltage infrastructure for testing a diverse range of batteries and cell modules.

Electrical characteristics modes. When it is used as a drain (second vides the batteries with the right tem- quadrant), it fully replicates the power perature by means of air, coolant or Since the end of 2010, Porsche Engi- electronics, including the drive motors, refrig erant. neering has been using a so-called which consume large amounts of power. “direct current source/drain” with a An interesting side effect is that the By using the thermodynamics test stand, maximum capa c ity of 300 kW for the power taken from the battery can be fed all battery types with various types of operation start-up of high-voltage bat- back into the power grid. cooling systems can be tested and teries developed in-house. started up. There is also the option to Thermal characteristics simulate extreme thermal conditions in In its function as a source (first quad - the upper limits of what the battery rant), it is possible to charge the battery Since 2011, Porsche has also been using can withstand, for which the battery can in constant-current and constant-voltage a thermodynamics test stand. This pro- also be preconditioned.

Particular electrical characteristics Particular thermal characteristics

•DC output voltage range: 8 to 800 volt • Coolant temperature •DC output current range: +/800 amps management: 20 kW cooling and heating power • Power range: up to 300 kW • Coolant temperature: 5 to +105 degrees Celsius • Power factor: 0,99 • Coolant flow: 3 to 60 liters per minute at maxi- • Efficiency at 300 kW: 91% mum operating pressure of 4 bar • Voltage tolerance: +/–1%/current tolerance 0.3% • Controllable using a CAN • Refrigerant cooling: up to 15 kW with R134a control unit • Air cooling: 1,000 liters per second at • Short-circuit resistant 5 to +80 degrees Celsius

Simplified diagram of the source/drain 1. AC input 2. Transformer 3. Controlled rectifier 4. 800 volt intermediate circuit 5. Bidirectional buck/boost converter

Porsche Engineering Magazine 1/2012 19 S.19-21_Quelle-Senke_RZ-EN+Feindaten_PE_Magazin_S4-9_RZ 18.04.12 18:40 Seite 2

High-voltage and thermodynamics test stand High-voltage and thermodynamics test stand

The source/drain is connected to the of prototype batteries. After checking extremely dependent on cell chemistry, (see issue 01/2011 of the PorschPorschee En- three-phase current (see point 1 in the their component arrangement, a series are tested using an external power mea- Typical safety test cases gineering Magazine), the internal re sis - figure on page 19). The AC voltage is of electrical and thermal safety tests surement and Coulomb counting device. tance of the battery was repeatedly

doubled via a transformer (see point 2). can be carried out. This includes a fa - 1. Testing of the BMS deactivation function: Charging or discharging power above the tested on the cell level, thereby identify- A controlledcontrolled rectifier (see point 3) con- tigue test and the classification of differ - Design verification maximum permitted limit is fed in or out. This tests whether the BMS disables the ing the health of the battery (see figure verts the AC voltage into a direct voltage ent batteries. contactors within the required time frame. "State of Health" below). of 800 volt DC. A capacitor forms the Based on electrical load profiles and 2. Precharging against a short-circuit: The facility is configured for a short-circuit. intermediate circuit, and typical voltages Operation start-up of the Battery the necessary minimum capacity of the The precharging algorithms in the BMS must recognize this situation and log PorschePorsche Engineering integrates expertise a fault. The main contactors must not be activated. can be simulated using a bidirectional, Management System (BMS) power storage unit, the battery cells are from various areas for the development 3. Insulation resistance: a defined parasitic resistance is connected between the chassis buck/boost converter. selected and the high-voltage power and the negative terminal of the battery. The BMS must clearly detect this. of high-voltage batteries. With individual StartingStarting up a high-voltage battery system circcircuituit and the thermal circuitry in the tests and analysis tailored for customer 4. Overcharging protection: The battery is charged until it has reached end-of-charge The system has two separate current firstly requires the calibration of the battery system are designed. For this voltage. During the constant-voltage phase a higher voltage is fed in carefully. requirements, Porsche Engineering can controllers. These enable the extremely Battery Management System in order to the temperature measurement points, The BMS must disable the contactors. provideprovide engineering services for diverse dynamic controcontroll of the current with ad- check the basic system functions. The which optimally define the thermal state projects, from an electric scooter to a justable low-voltage and surge protec- cell voltage in the cell controllers, the of the battery, also have to be laid out. fully electric sports car all according to tion settings. activation of the contactors, the man - Safety tests tests and the testing of electric vehi- the principle of Porsche Intelligent Per- agement of chargingcharging and discharging,discharging, Electrical and thermal design character - cles, in order to attain a precise de scrip - formance. The battery under test and the testing and the thermal management are all istics are significantly defined by the High-voltage batteries and conventional tion of the current state of the battery facility are physically separate and are checked one by one in this process. basic electrical power capacity, safety batteries must fulfill the highest safety during every revision. As part of the Emmanuel Dhollande, Volker Sonn, controlled from a control room. The and reliability, and the lifespan of the standards. In particular, the high voltage Boxster E research project, for exam ple, Björn Pehnert testing chamber is also equipped with Through an iterative process, the resis - power storage system. of the battery requires a high level of in- an array of safety mechanisms. tance- and temperature-dependent pa - sulation resistance against the chassis ram eters are defined (for example tem - In order to make sure that the design of of the vehicle at both terminals. High load State of Health Using the testing facility per ature-dependent electrical charging the system is correct, a combination of profiles also result in significant power and discharging limits). The electrical various testing methods is used. Using dissipation in the battery, which in turn OCV (before the discharge pulse) ➜ The facility is used for the operation sensor in the battery and the state-of- syn thetic load profiles, the character istics leads to it heating up. During safety Current [A] Current start-up testing and design verification charge (SOC) BMS algorithms, which are of the electrical and thermal cir cuitry can tests, derating functions including deac- OCV (after the discharge pulse) ➜ Voltage [V] Voltage

be established. tivation are checked by conditioning the 200 battery and running it through load pro- 360 Battery current The internal resistance of the battery files. These are then mapped in hard- system can be precisely measured. By ware-in-the-loop test vectors, which were 100 allocating internal resistance parts and developed especially for this purpose by 340 ➜ various system components (cells, cell Porsche Engineering. Typical safety test Battery voltage 0 connectors, busbars, etc.), potential cases can be seen in the table above. areas for optimization can be precisely 320 -100 identified. Classification/fatigue testing ➜

Cross section of Load pulse 1 C (80 amps)

➜ the high-voltage ➜ The testing and optimization of the con- Along with testing the perfect construc- 300 battery in the -200 Load pulse Analysis of internal Boxster E trol strategies of the BMS for thermal tion of the battery with the naked eye, 3.75 C (280 amps) resistance using research vehicle, management and the approval of power/ the battery is also the subject of tar - pulse discharging which was tested 280 provides precise voltage limits are generally carried out geted testing for hidden thermal and -300 thoroughly on data about the the high-voltage using load profiles,profiles, which are based on electrical resistance at its source/drain. 0 100 200 300 400 500 600 700 800 900 1 state of health of testing stand real driving cycles. Above all this makes sense in endurance the battery

20 Porsche Engineering Magazine 1/2012 Porsche Engineering Magazine 1/2012 21 S.19-21_Quelle-Senke_RZ-EN+Feindaten_PE_Magazin_S4-9_RZ 18.04.12 18:40 Seite 2

High-voltage and thermodynamics test stand High-voltage and thermodynamics test stand

The source/drain is connected to the of prototype batteries. After checking extremely dependent on cell chemistry, (see issue 01/2011 of the Porsche En- three-phase current (see point 1 in the their component arrangement, a series are tested using an external power mea- Typical safety test cases gineering Magazine), the internal re sis - figure on page 19). The AC voltage is of electrical and thermal safety tests surement and Coulomb counting device. tance of the battery was repeatedly doubled via a transformer (see point 2). can be carried out. This includes a fa - 1. Testing of the BMS deactivation function: Charging or discharging power above the tested on the cell level, thereby identify- A controlled rectifier (see point 3) con- tigue test and the classification of differ - Design verification maximum permitted limit is fed in or out. This tests whether the BMS disables the ing the health of the battery (see figure verts the AC voltage into a direct voltage ent batteries. contactors within the required time frame. "State of Health" below). of 800 volt DC. A capacitor forms the Based on electrical load profiles and 2. Precharging against a short-circuit: The facility is configured for a short-circuit. intermediate circuit, and typical voltages Operation start-up of the Battery the necessary minimum capacity of the The precharging algorithms in the BMS must recognize this situation and log Porsche Engineering integrates expertise a fault. The main contactors must not be activated. can be simulated using a bidirectional, Management System (BMS) power storage unit, the battery cells are from various areas for the development 3. Insulation resistance: a defined parasitic resistance is connected between the chassis buck/boost converter. selected and the high-voltage power and the negative terminal of the battery. The BMS must clearly detect this. of high-voltage batteries. With individual Starting up a high-voltage battery system circuit and the thermal circuitry in the tests and analysis tailored for customer 4. Overcharging protection: The battery is charged until it has reached end-of-charge The system has two separate current firstly requires the calibration of the battery system are designed. For this voltage. During the constant-voltage phase a higher voltage is fed in carefully. requirements, Porsche Engineering can controllers. These enable the extremely Battery Management System in order to the temperature measurement points, The BMS must disable the contactors. provide engineering services for diverse dynamic control of the current with ad- check the basic system functions. The which optimally define the thermal state projects, from an electric scooter to a justable low-voltage and surge protec- cell voltage in the cell controllers, the of the battery, also have to be laid out. fully electric sports car all according to tion settings. activation of the contactors, the man - Safety tests tests and the testing of electric vehi- the principle of Porsche Intelligent Per- agement of charging and discharging, Electrical and thermal design character - cles, in order to attain a precise de scrip - formance. The battery under test and the testing and the thermal management are all istics are significantly defined by the High-voltage batteries and conventional tion of the current state of the battery facility are physically separate and are checked one by one in this process. basic electrical power capacity, safety batteries must fulfill the highest safety during every revision. As part of the Emmanuel Dhollande, Volker Sonn, controlled from a control room. The and reliability, and the lifespan of the standards. In particular, the high voltage Boxster E research project, for ex am ple, Björn Pehnert testing chamber is also equipped with Through an iterative process, the resis - power storage system. of the battery requires a high level of in- an array of safety mechanisms. tance- and temperature-dependent pa - sulation resistance against the chassis ram eters are defined (for example tem - In order to make sure that the design of of the vehicle at both terminals. High load State of Health Using the testing facility per ature-dependent electrical charging the system is correct, a combination of profiles also result in significant power and discharging limits). The electrical various testing methods is used. Using dissipation in the battery, which in turn OCV (before the discharge pulse) ➜ The facility is used for the operation sensor in the battery and the state-of- syn thetic load profiles, the character istics leads to it heating up. During safety Current [A] Current start-up testing and design verification charge (SOC) BMS algorithms, which are of the electrical and thermal cir cuitry can tests, derating functions including deac- OCV (after the discharge pulse) ➜ Voltage [V] Voltage be established. tivation are checked by conditioning the 200 battery and running it through load pro- 360 Battery current The internal resistance of the battery files. These are then mapped in hard- system can be precisely measured. By ware-in-the-loop test vectors, which were 100 allocating internal resistance parts and developed especially for this purpose by 340 ➜ various system components (cells, cell Porsche Engineering. Typical safety test Battery voltage 0 connectors, busbars, etc.), potential cases can be seen in the table above. areas for optimization can be precisely 320 -100 identified. Classification/fatigue testing ➜

Cross section of Load pulse 1 C (80 amps) the high-voltage ➜ The testing and optimization of the con- Along with testing the perfect construc- 300 battery in the -200 Load pulse Analysis of internal Boxster E trol strategies of the BMS for thermal tion of the battery with the naked eye, 3.75 C (280 amps) resistance using research vehicle, management and the approval of power/ the battery is also the subject of tar - pulse discharging which was tested 280 provides precise voltage limits are generally carried out geted testing for hidden thermal and -300 thoroughly on data about the the high-voltage using load profiles, which are based on electrical resistance at its source/drain. 0 100 200 300 400 500 600 700 800 900 1 state of health of testing stand real driving cycles. Above all this makes sense in endurance the battery

20 Porsche Engineering Magazine 1/2012 Porsche Engineering Magazine 1/2012 21 Expansion at the Weissach Development Center

Weissach is growing. And so are the engineering services by Porsche.

With extensive construction projects, Porsche is now implementing a long-term strategic site plan for its research and development center in Weissach. The sports car manufacturer is investing around €150 million in a high-tech wind tunnel, a state-of-the-art design center, and an innovative electronics integration center. This means one thing above all for engi- neering services by Porsche: first-class resources for demanding projects.

New high-tech wind tunnel Cutting-edge design studio been scattered across several buildings at the Weissach site belonging to Porsche With the new wind tunnel, Porsche is Outstanding design has always been one can be bundled under one roof. Working equipping itself to be able to fully meet of Porsche’s strongest areas of expertise. in close proximity is a major advantage. and overcome the technological chal- Above all, the new studio will provide Especially in electronics, which now plays lenges involved in automotive develop- more space for the Porsche designers, a role in almost every vehicle component, ment in the future. “Good aerodynamics who are closely involved in the earliest the close interaction between different makes an important contribution to- concept phases of every vehicle devel- electrical system/electronics experts from wards lower fuel consumption and better opment process. Due to an increased related specialist fields during develop- perfor mance – which are both impor- workload, greater capacity for sports ment contributes significantly to the suc- tant aspects of implementing Porsche car construction is urgently needed at cess of projects. With the new electronics Intelligent Performance,” explains Wolf- the Weissach center of competence. integration center, Porsche is creating gang Hatz, board member in charge of the optimum conditions for its objective research and development at Porsche An electronics integration to “continue developing electric and hy- AG. These new facilities will help Porsche center for the future brid technology,” according to Hatz. to maintain its top position in the field of aerodynamics and to further extend In the new electronics integration center, As the facility will not just be used exclu- its lead. various subdivisions that had previously sively for development work by Porsche,

22 Porsche Engineering Magazine 1/2012 Expansion at the Weissach Development Center

but will also continue to be available for Porsche projects with external cus- WEISSACH MILESTONES tomers, it can be accessed directly from the design center located beside 16 October 1961 Work begins on the test track (construction of the skid pad) it, but also has its own entrance for the 1967–1970 Construction of circuit and “rough-road” track discreet fulfillment of confidential cus- facilities for further testing purposes tomer projects. 1969 Construction of additional testing stands, workshops, and facilities for experiments; the cornerstone of today’s Prepared for the future Weissach Development Center 1974 Construction of an office building in the shape The comprehensive range of resources of a hexagon, which provides the ideal layout for close already available for external customer cooperation and teamwork projects at the Weissach Development 1982 The Environmental Technology Measurement Center Center today is now being invested in moves into building 26 (with testing stands that will fulfill and expanded significantly. regulations for decades to come) 1983 Construction of testing building for engines and units “The symbiotic connection with the 1986 Inauguration of the most modern wind tunnel of its time Weissach Development Center is a with the best possible air flow quality and completion of the unique feature of Porsche Engineering crash testing facilities in the automotive sector,” says Malte 2002–2004 Completion of additional office buildings and the tire center Radmann, managing director of Porsche (testing facility for fatigue and brake tests) Engineering. With the development cen- 2007 Opening of a four-story drivetrain center (a combined ter’s unique and high-tech infrastruc- workshop and office) ture, Porsche Engineering will continue 2011 Construction begins for the long-term strategic site plan to be able to provide the optimal condi- with a high-tech wind tunnel, state-of-the-art design center, tions for engineering services projects and electronics integration center for the future in the future.

Porsche Engineering Magazine 1/2012 23 Vehicle interior climate control

Keeping cool in future

Due to new alternative drivetrain designs for the vehicles of today and tomorrow, the entire basis of vehicle interior climate control is changing. Porsche Engineering is there- fore ensuring that an integrated thermal management system is being developed now.

Some factors that influence the climate of the vehicle interior

Physical factors Physiology

• Air temperature • Physical constitution • Relative humidity • Sex • Thermal stratification, • Age vertical/horizontal • Ethnic factors • Thermal radiation • Food intake • Air circulation • Air quality Subjective factors • Atmospheric electricity • Acoustics • Clothing • Visual factors • Level of activity • Number of passengers • Level of acclimatization • Seasonal changes to • Daily/annual rhythm important physical factors

➥ “Comfort is the absence of disturbing factors”

Comfortable vehicle climate A moderate interior climate, or “com- de-icing the windshield and windows fort” in the vehicle, can be basically re- within a defined time (for example, when Customers today expect a comfortable duced to the “absence of disturbing fac- cold-starting in the winter) and keeping temperature in the interior of their ve- tors”. The factors influencing this sense the windows free from condensation. hicles – regardless of the conditions of comfort can be subjective as well as prevailing outside. Multi-zone climate physical or physiological. It is also important to remember that the control units in the front and back, pro- driver’s reaction capabilities and concen- vide the option to create a comfortable Along with creating and maintaining tration in difficult situations will be better climate for each passenger, as is the a comfortable vehicle interior climate the more comfortable he or she feels. case, for example, with the Porsche through cooling and/or heating it, cli- This means that the temperature must Panamera’s state-of-the-art optional mate control must also fulfill legislative be right from head to toe (what is known Four-Zone Climate Control. and safety requirements. This includes as stratification: “a cool head and warm

Panamera: fuel consumption (in l/100 km) combined 12.5-6.3; CO2 emissions 293-159 g/km 24 Porsche Engineering Magazine 1/2012 Vehicle interior climate control

feet”). The air distribution, cleanliness and humidity must also be exactly right.

How a conventional climate control system works

Basically there are three main operating modes for the climate control system in a vehicle:

• Pure heating mode: quickly heating the cold interior of the vehicle in winter

and de-icing the windshield when tem- The optional Four-Zone Climate Control in the enables individual, targeted climate peratures outside are low. control

• Combination mode: automatic con- The climate control unit measures the are taken into account and checked in trol of the vehicle climate (“car climate conditions outside as well as the current the early stages of vehicle development, 22 degrees Celsius”/71.6 degrees conditions in the vehicle interior and before the climate control system is de- Fahren heit). Additional fresh air is first compares them with the target require- signed, as their effects can vary widely dehumidified and is then brought to ments. Thus, the climate control system depending on the vehicle in question. the right temperature, to keep the can achieve the required climate using windshield and windows free from the three modes. Targeted individual cli- How a conventional refrigeration condensation. This combined mode is mate control can be achieved in this way, circuit works the most common one for climate which the two-zone automatic climate control systems in Central Europe, due control system of the new The most important parts of a climate to the climate conditions there. is capable of, for example. control system are the refrigeration and cooling circuits. While the refrigeration • Pure cooling mode: quickly cooling These are the basic customer require- circuit provides the energy to cool down the warm vehicle interior of the vehicle ments and expectations for future cli- the vehicle, the cooling circuit for the in summer, when temperatures out- mate control systems, regardless of the combustion engine collects the energy side are high. drive unit design of the vehicle. for heating up the vehicle interior.

A conventional vehicle climate control Factors that influence vehicle Refrigerant sucked in by the compressor system design consists of the following climate control system designs circulates in the refrigeration circuit. This components in addition to the actual circuit is divided into two sections: a climate control unit: a refrigeration cir- Climate control in vehicles is influenced high-pressure and a low-pressure sec- cuit (provision of cold air) and a cooling by many different factors. These include tion. The refrigerant, in the form of a circuit (provision of warm air), air ducts the size of the passenger space, the de- gas, is heated in the compressor by with outlet vents, a climate control op- sign of the dashboard, the size and angle being compressed and then channeled erating unit and a climate control de- of the windshield, the thermal mass that through the condenser under high pres- vice (with its corresponding electrical needs to be climate controlled, the ex - sure. There, heat is absorbed from the parts such as a cable harness and sen- terior aerodynamics and thermal manage - hot gaseous refrigerant, leading to a liq- sors, for example). ment in the vehicle. All of these factors uefaction of the gas.

911 (Type 991): fuel consumption (in l/100 km) combined 9.7-8.2; CO2 emissions 229-194 g/km Porsche Engineering Magazine 1/2012 25 Vehicle interior climate control

Then the refrigerant enters the drier/ Hybrid components in the Panamera S Hybrid collector. In order to protect the refriger- ation circuit from damage, impurities 2 and water are separated from the refrig- erant in the drier. The refrigerant is then 1 passed from the drier to the expansion 4 5 valve and enters the evaporator in a mostly liquid form. There it is vaporized by absorbing heat. Because it has 3 absorbed heat from the surrounding en- vironment, the air is cooled and dehu- midified. The moisture created by dehu- midifying the air is taken away via tubes. 1. High-voltage nickel metal hydride battery 4. Hybrid module 2. Air supply duct 5. Supercharged 3.0-liter V6 engine On very humid days, this moisture can 3. Power electronics appear in the form of a puddle under the vehicle. In the low-pressure section, Hybridization This is made possible by special evapora- the gaseous refrigerant is sucked back tors, which can store the cooling energy into the compressor and the cycle begins Vehicles with hybrid drive units have a for a certain period (storage evapora- all over again. conventional combustion engine sup - tors), and by high-voltage PTCs for elec- ported by an electric motor. Electric trical heating. Another major challenge Future challenges power is stored in a battery, which also for climate control and thermal manage- must be kept cool. In the Panamera S Hy- ment system design is ensuring that the In conventional drive unit designs suffi- brid, the high-voltage nickel metal hydride drivetrain heats up quickly in order to re- cient „free“ energy for a comfortable cli- battery is cooled by air. The challenge for duce fuel consumption and emissions. mate inside the vehicle is available in the climate control system in a vehicle form of „waste heat“ from the combus- with a hybrid drive is the additional cool- Electric vehicles tion engine. With alternative drive unit ing required for the electrical compo- designs such as those in electric vehi- nents such as the battery, power elec- Electric vehicles – like the Porsche cles, however, the energy for heating the tronics and the electric motor. As hybrid Boxster E research vehicle – use batter- vehicle must be additionally generated. drives also usually have a start/stop func- ies that require a temperature range of The efficiency of the individual electrical tion and can drive a certain distance on between 20 and 30 degrees Celsius (be- components is significantly higher in electric power alone, the climate control tween 68 and 86 degrees Fahrenheit) in electric vehicles than in combustion en- system must be designed so that it can their drivetrains. This temperature range gines. The missing energy in the form of operate without a combustion engine. ensures that the batteries function prop- heat that must be electrically generated erly and prevents them from “getting old” in vehicles with electric vehicle drive This means that the refrigeration and too quickly. This means that the batteries units means that there is less energy cooling circuit components, such as the do not just need to be cooled down, but available to propel the vehicle. The chal- compressor, must be powered electri - sometimes also warmed up, depending lenge therefore consists of maintaining a cally and can no longer be mechanically on ambient temperatures. comfortable climate in the vehicle inte - linked to the combustion engine, in or- rior with as little energy as possible, in der to ensure that the climate control Cooling with air, which is currently the order to affect the vehicle’s driving range system still functions when the vehicle standard method in hybrid drives, is no as little as possible. has stopped at traffic lights, for example. longer sufficient and must be replaced

26 Porsche Engineering Magazine 1/2012 Vehicle interior climate control

with liquid cooling methods using appro- priate refrigerants or coolants. Climate control and thermal management are therefore becoming more complex and require new thinking.

The aim of the thinking behind the new designs at Porsche Engineering is to re- duce the amount of heating required in the vehicle. There is potential in improved insulation, which will result in the loss of less heat via the body and the windows, and the reduction of the thermal mass to be heated in the vehicle’s interior.

Innovative solutions

Options for new climate control system Batteries like those in the Boxster E research vehicle need to be warmed up as well as cooled down, design being considered strongly at depending on ambient temperatures Porsche Engineering are the use of aux - iliary heating systems (such as heat using previously identified performance is true for the inclusion of new compo- pumps, electric auxiliary heaters, fuel- data, cooling and heating needs, and nents in climate control and thermal powered auxiliary heaters) and targeted driving profile requirements. management system design. Along with climate control according to the number cooling the batteries in order to increase of passengers in the vehicle. Other areas Conclusion: challenges and their lifespan, heating the batteries is being focused on are the use of thermal solutions also becoming more important. storage systems, the preheating or pre- cooling of the vehicle interior while the Climate control and thermal manage- Porsche Engineering is developing solu- vehicle is being charged at the electrical ment play a very important role when tions for these challenges based on com- power outlet, or the use of direct and designing hybrid and electric vehicles, prehensive electromobility experience surface heating devices in the and as the increasing electrification of vehi- from internal and external engineering the steering wheel. cles leads to a decrease in the number projects, as well as thermal management of available sources of heat. As a result, expertise from classic sports car design. The cooling agents and cooling and today’s standard method of reusing the Using all the tools available to them, from heating methods are selected by engi- (free) engine waste heat is becoming simulation and calculation tools to com- neers in the earliest stages of the design increasingly difficult or even impossible. ponent testing on test stands and the process. For this purpose, Porsche Engi- testing of entire vehicles in the climate neering has developed its own thermal The more effective use of heated or wind tunnel and on the test track, engi- simulation tool, which was validated by cooled air in the vehicle interior, better neers at Porsche Engineering are creating tests. This can be used to work out and insulation and further modifications in the climate control and thermal manage- define the optimum climate control and the vehicle contribute to reducing en - ment system designs of the future. thermal management system design at ergy consumption for the heating and an early stage of vehicle development, cooling of the vehicle interior. The same Sebastian Ost, Michael Müller, Patrik Gisch

Panamera S Hybrid: fuel consumption (in l/100 km) urban 7.6-7.4 · extra-urban 6.8-6.6 · combined 7.1-6.8, CO2 emissions 167-159 g/km

Porsche Engineering Magazine 1/2012 27 Special exhibition “80 Years of Engineering Services by Porsche”

Who developed it? Porsche.

Around 20 projects from 80 years of engineering services by Porsche were exhibited in the Porsche Museum

For more than 80 years, Porsche has been globally active as an engineering services provider for external clients. Engineering services are an essential part of the Porsche core, and some of its most interesting developments were presented in the Porsche Museum.

“In the special exhibition ‘80 Years of “The engineering services by Porsche cylinder, light-alloy engine with 1.7 or 2.0 Engineering Services by Porsche’, the are the oldest business segment in the liters displacement, which would later Porsche Museum and Porsche Engineer- Porsche company. When the company also power the famous Front. ing presented a selection of exciting was founded, there were no plans to projects and in this way, we have built a build its own sports cars yet,” says Two years later, contracted bridge from the past into the future,” Stejskal. And so, as part of the special the design of a Grand Prix racing car – says Achim Stejskal, head of the Porsche exhibition, around 20 special exhibits one of the most legendary racing cars of Museum. “As an engineering services were on display, ranging from the deve l - all time. Driven by racing heroes like provider, and his opment of entire vehicles, through en- Hans Stuck and Bernd Rosemeyer, the team have established an international gines and transmissions, to extraordinary Auto Union “P-Rennwagen” achieved no reputation for excellence – thousands of industrial projects in the present. less than 30 Grand Prix victories and 15 customer projects have been completed world records between 1934 and 1937. since the foundation of the engineering One of the exhibits was one of the first services office in 1931.” ever Porsche development projects, which was contracted to the engineer- A large number of invited guests and for- ing office by the automotive mer Porsche employees, including racing manufacturing company in Chemnitz in legends and Peter Falk, at- 1931: the Wanderer W 22, also known tended the opening celebrations of the as Model 7 in the internal classification exhibition, which ran from June 21 to Sep- system created by Porsche. The mid-size One of the first ever engineering services projects by tember 11, 2011 in the Porsche Museum. W 22 was well-known for its six- Porsche: the Wanderer W 22 from 1931

28 Porsche Engineering Magazine 1/2012 Special exhibition “80 Years of Engineering Services by Porsche”

Above: Porsche engineers developed a bobsled for the professional sportsman Georg Hackl

Left: Porsche Engineering developed a new engine for the V-Rod model by Harley-Davidson

wanted to see for himself how his time guests, car lovers and technology Porsche bobsled was being exhibited at enthusiasts alike marveled at astonishing the “80 Years of Engineering Services engineering projects for external cus- by Porsche” exhibition – and so hon- tomers, some on show for the first time ored the Porsche Museum with a per- ever. The exhibition organizers were sonal visit. Hackl won the silver medal more than happy with the positive re- at the 2002 Olympics in Salt Lake City sponse: with around 90,000 enthusiastic

Thinking outside the box: Porsche was con tracted with that very sled. Another unusual visitors, the special exhibition for the 80- to design the Zafira for Adam Opel AG exhibit was the Adventure electric, full- year anniversary of Porsche engineering suspension wheel chair, which was de- services was a complete success. The compact MPV, designed signed by Porsche in 2004 for the com- by Porsche in 1994 for Adam Opel AG, pany Ulrich Alber GmbH. was also exhibited, along with the Mer- cedes Benz 500 E, the series production “80 Years of Engineering Services by of which was even carried out in the Porsche” was a unique exhibition: first- Porsche factory in between 1990 and 1994.

The anniversary exhibition, the most elaborate special exhibition to date in the museum, also surprised visitors A compact history: the history of engi- with many unusual Porsche develop- neering services by Porsche, including ment projects from outside the automo- lots of background information and ad- tive sector: along with a Harley-Davidson ditional pictures, is available as the an- V-Rod and the sports watercraft Seabob, niversary special edition “80 years of the Porsche Museum also showed an pioneering solutions - Porsche Engi- original bobsled developed by Porsche neering” from bookstores and the mu- engineers in collaboration with the pro- seum shop at the Porsche Museum in fessional sportsman Georg Hackl. The Around 90,000 visitors marveled at the variety of -Zuffenhausen (ISBN 978-3- Olympic sledding champion apparently Porsche developments 9812816-8-2).

Porsche Engineering Magazine 1/2012 29 Clutch robot

Smoother control using robotics

Requirements for vehicle drivetrains are constantly increasing, especially with regard to the comfortable start-up of vehicles with manual clutches. In order to efficiently analyze the clutch characteristics (clutch engagement and start-up characteristics) and to be able to reproduce these results, Porsche Engineering has developed a unique clutch robot in collaboration with the Münster University of Applied Sciences (Automation and Robotics department).

Robotic systems have been used in vehi- ware, in most cases they are used only closed-loop control is possible for these cle pedal operation testing for some time to simulate distance profiles on roller systems, and the pedals cannot be posi- now. The existing systems present var - dynamometer test stands. Using these tioned precisely so that conditions can ious problems, however. Because they systems for vehicles actually driving out- be reproduced. They are therefore not require external sources of power and doors is basically impossible. Further- very useful for the analysis of clutch en- lots of space for their computer hard- more, only open-loop control but not gagement characteristics. For this reason,

30 Porsche Engineering Magazine 1/2012 Clutch robot

The clutch robot is linked to the user Optimum analysis of clutch characteristics operator laptop by an Ethernet interface and is operated simply via an easy-to- Requirements use user interface.

• Compact setup for the hardware and the power source, so that the system can also be used in vehicles without much space in the interior Adjusting the position • Simple assembly of the system without having to modify the or the driver’s footwell in all vehicle classes The cable pull sensor first detects the • Logging of variables to be measured in real time current position of the clutch pedal. • Logging of pedal positions independently of the dynamics of the driver’s seat Based on the current position and the • Definition of the pressure placed on the pedal independently of the position target position, the controller imple- of the robot • Operation of all three pedals by the robot mented in the RTOS calculates the cor- • Highly dynamic processes that can be reproduced exactly recting variable for the linear motor. (e.g. snap starts/racing starts) The implemented controller must be precise and extremely stable through - out the whole application area. Differ ent Porsche Engineering has developed a After the main unit has been fitted in driver’s seats in particular make the new clutch robot that solves these prob - the vehicle, a head unit is mounted on setup of the controller more difficult in lems (an overview of the requirements it top of it. The three motors are then con- this regard. In sports cars the seats are had to meet is shown in the information nected directly to the head unit via a generally very firm, while in small cars box above). docking connecter, so that there is no they are generally softer. In order to take need for extra cables when setting up the varying dynamics of driver’s seats Hardware configuration the robot in the vehicle. The controllers into account, various components have for the motors, and the computer sys - been added to the PI controller. The The main unit of the clutch robot con- tem with a real time operating system controller is therefore completely stable sists of aluminum plates, which can be (RTOS) and sensor signal processing, throughout the whole area of applica- modified to fit the shape of the driver’s are located in the head unit. The exter- tion, and there is no need for the user seat and the interior of the vehicle. In nal sensors, such as the cable pull sen- to modify it any further. the main unit, three independent, closed- sors or the vehicle CAN bus, can be loop controllable linear motors are used connected to the system with standard Areas of application to operate the three pedals. connecters. Various testing processes can be carried The motors are connected to the pedals Power is provided by a separate block out with the clutch robot. The following via adapter plates and a coupling bar and is connected to the head unit via a three kinds of tests are the most impor- that can be adjusted in length, and the cable. This set-up makes it possible to tant applications: pressure on the pedals is measured by a position the power supply anywhere in load cell integrated into the coupling bar. the vehicle. Because the whole system • Pedal pressure measurement The pedal position is detected by cable is separated into three components • Start-up testing pull sensors, which are fixed firmly in the (see figure on page 32) – the main unit, • Stall testing footwell of the driver’s seat and can there - the head unit and the power unit – it fore be used for position control with out can be transported easily and installed With the aid of powerful analysis soft- influence by the seating dynamics. in the vehicle quickly. ware, at the start of testing, the user

Porsche Engineering Magazine 1/2012 31 Clutch robot

3

2 1

4 5 6

9

8 7

Design of the clutch robot: can choose which correcting variables an initial evaluation of the measure- 1. Head unit should be saved in a measurement file ments while the test is still going on. 2. Connection panel by the system with up to 1 kHz. The 3. Connection to power supply 4. Main unit user also has the option to directly con- Pedal pressure measurement 5. Linear motors nect external temperature sensors to 6. Coupling bars the system. There are also interfaces During the pedal pressure measure- 7. Load cell 8. Cable pull sensors with the vehicle CAN bus and/or with ment test, the pressure placed on the 9. Power supply CAN-based measurement systems. Data clutch pedal and the pedal travel are collection is carried out by the robotic recorded. Before the test begins, the system itself, and the recorded data combustion engine speed can be set to can be uploaded to the user PC after the desired number of revolutions via the test has been carried out, in order the clutch robot. The clutch pedal is to visually illustrate and evaluate the then pressed down fully and subse- results. A live readout of the test en - quently brought back to its starting ables the testing engineer to carry out position. The number of test repetitions

32 Porsche Engineering Magazine 1/2012 Clutch robot

Stall testing Force/displacement curve Kraft-Weg-Kennlinie 150 Stall testing is similar to the vehicle

140 start-up test, although here the vehicle

130 is fixed in position with a tow bar. The objective of this test is to establish the 120 drive dynamics and the stability of the 110 engine control unit in relation to the en- 100 gagement characteristics of the clutch. 90 The tractive power is recorded by the 80 elaborate robotic system. The behav ior 70 Kraft [N] Force [N] Force of the engine is recorded at variable 60 clutch engagement speeds, all the way 50 down to standstill. 40 30 Conclusion 20

10 With the new clutch robot, the engi-

0 neers at Porsche Engineering have de- 0 20 40 60 80 100 120 140 160 DisplacementWeg [mm] [mm] veloped a system that intelligently meets a number of current challenges: the sys - Analysis software enables a preliminary assessment during the pedal pressure test tem has an integrated source of power, Pedal pressure measurement which can be fed from the vehicle power circuit or can be supplied with electricity as well as the speed of pedal operation kept in a constant position by the clutch by an independent battery pack. This can be selected by the user. The result robot during the entire test. The clutch makes it possible to carry out tests on consists of curve graphs depicting pedal engagement speed during vehicle start- vehicles driving outdoors. Measurement pressure in relation to combustion en - up is then varied. data collection is carried out by the ro- gine speed. bot itself. The simple setup and removal The brake pedal can also be set at a of the robot does not require the re - Start-up testing desired position in order to prevent the moval of any vehicle components. This movement of the vehicle before the test enables benchmark testing in several The aim of the start-up test is to mea - begins or to simulate vehicle start-up in vehicles within a very short period of sure the clutch engagement limit speed. relation to braking power. Depending time. Finally, by utilizing its own sensors What is meant by this is the maximum on the set-up of the test, the brakes can and carrying out its own data collec- speed with which the clutch pedal can be automatically released before the tion, no additional measurement pro- be operated, and at which starting up clutch pedal engages at a previously de- cesses are required – the clutch robot the vehicle is still safe. fined, constant speed. After the test has therefore significantly simplifies test - finished, the robot disengages and the ing the functions of man ually operated Before the test starts, the clutch pedal accelerator pedal returns to the idle po- clutches in vehicles. is pressed down completely. Then the sition. Because the tests can be repro - user can set the desired combustion duced in different vehicles, objective com- Philipp Kamping, Johannes Aehling, engine speed. The accelerator pedal is parisons can be made between them. Dr. Jan-Peter Müller-Kose

Porsche Engineering Magazine 1/2012 33 Impressum

Impressum Porsche Engineering Magazine

Publisher Editor Porsche Engineering Group GmbH Frederic Damköhler

Address Design: Agentur Designwolf, Stuttgart Porsche Engineering Group GmbH Repro: Piltz Reproduktionen, Stuttgart Porschestrasse Printing: Leibfarth&Schwarz, Dettingen/Erms 71287 Weissach, Translation: TransMission Übersetzungen, Stuttgart All rights reserved. No part of this publication may be repro - Tel. +49711 911- 8 88 88 duced without the prior permission of the publisher. We cannot Fax +49711 911- 8 89 99 guarantee that unrequested photos, slides, videos or manuscripts will be returned. E-mail: [email protected] Porsche Engineering is a 100% subsidiary of Website: www.porsche-engineering.com Dr. Ing. h.c. F. Porsche AG.

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34 Porsche Engineering Magazine 1/2012 Next Up

New. Dynamic. Trailblazing.

Ready for some new spirit? Issue 2/2012 of the Porsche Engineering Magazine will provide you with latest news on our engineering projects including details about the development of the new Boxster.

Boxster (Type 981): fuel consumption (in l/100 km) combined 8.8-7.7; CO2 emissions 206-180 g/km For further information, please visit www.porsche-consulting.com.

You don’t need to build sports cars to deliver fast solutions, but it helps.

Porsche Consulting.