MDDP Project - Advanced City Bus 2013
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MDDP 2012/2013 Advanced City Bus Final Report 14nd January 2013 By: David Williams Robert Spencer Francesca Rapley Khairul Zamani Morgan Schofield Mike Frazer Supervisors: John Mackey, John Doherty, Aldo Sorniotti Abstract This report builds on the concept presented in the Inception Report and presents a final conceptual design for an Advanced City Bus. Through innovative technology and thoughtful design, the presented vehicle is 51% more fuel efficient and produces 33.8% less CO2 than the Alexander Dennis Enviro300 baseline vehicle when at full capacity. The design is visually more appealing, offers an enhanced user experience. This technical report details and justifies the design choices made in creating the Advanced City Bus and presents financial and environmental analysis of the positive impact the vehicle can have for a long term fleet operator. MDDP Project - Advanced City Bus 2013 1. Executive Summary In an increasingly environmentally conscious world, the impact that the transport industry has on the world's climate is the subject of much debate, and much concern amongst vehicle manufacturers. With consumers ever more aware of the implications of climate change and more demanding in the products they choose, it becomes increasingly more important to demonstrate that your business is actively engaging in green technology. In the car industry, this has become common place with the introduction of various hybrid technologies but in the public transport industry, limited advances have been made. Bus design has remained stagnant for years, with no major advances in technology emerging. In the current economic climate, characterised by sustained and rising fuel prices, this presents a serious concern to fleet operators. A typical single deck Enviro300 bus is capable of just 5MPG; fuel expenditure is a serious outlay. Urban buses spend the majority of their time travelling at very low speed; indeed the average speed of the drive cycle used in this concept design is only 8kmh due to the amount of passenger stops and traffic encountered on a typical drive cycle. The social climate also makes operating buses difficult. As seen in the surveys conducted during this report, the perception of public transport and buses in particular is very poor with issues such as poor ride comfort and undesirable vehicles being cited as common reasons for avoiding such vehicles. This is an area where making use of new and innovate technology can yield enormous improvements. To address these issues, the Advanced City Bus (ACB) is presented. There were objectives for the ACB project: Increase the fuel economy performance of the vehicle and demonstrate the long term benefit this could bring when compared to a conventional bus, Reduce the level of carbon dioxide emissions produced in operation and decrease the environmental impact that the advanced city bus has, Make the vehicle much more appealing to the end user by addressing public perception issues and by improving the technology and components on the vehicle. These issues where addressed by focusing on a variety of areas within the vehicle design. These included the vehicle chassis, drive train, propulsion systems, suspension system, bodywork, internal layout and anccilary technologies for passenger comfort. Page | II MDDP Project - Advanced City Bus 2013 By focussing on the vehicle chassis, a significant weight reduction was achieved. This was achieved through ANSYS simulation and optimisation of the chassis, whilst also analysing the viability and outcome of integrating sandwich panel honeycomb into the structure to benefit from weight savings and strength gains. An advanced drive train and propulsion system was developed for the ACB. Rather than a standard diesel engine, the ACB utilises a diesel series hybrid power train with an optimised gearbox for urban driving. Consisting of a 3.2L, 150kW diesel engine mated to a 145kW BAE Hybridrive electric motor, with a 30kWh battery, the ACB improves fuel economy by 51% compared to the Enviro300 baseline vehicle. The advanced chassis and innovate power train has a big impact on the environmental impact the vehicle makes. Taking into consideration the construction materials used during manufacturing, when compared to a standard bus the ACB demonstrates a 33.8% improved global warming impact. The ACB also produces significantly less CO2 in operation than a conventional vehicle. ACB Cost Saving Compared to Enviro300 £300,000.00 £250,000.00 £200,000.00 £150,000.00 £100,000.00 £50,000.00 £- Cumulative SavingsCumulative -£50,000.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 -£100,000.00 Years in Service Figure 1 - ACB Cumulative Savings The ACB concept's estimated cost is initially much higher than the equivalent Enviro300 vehicle, but as can be seen in Figure 1 the ACB rapidly brings savings in operation, breaking even after just 3 years of service thanks to the vastly improved fuel economy performance. This report presents the technical analysis, design and evaluation of the proposed Advanced City Bus, with a detailed financial and environmental life cycle analysis to quantify the impact that a fleet of advanced buses posses compared to conventional fleets. Page | III MDDP Project - Advanced City Bus 2013 2. Table of Contents 1. Executive Summary ................................................................................................................ II 3. List of Figures ...................................................................................................................... XII 4. List of Tables .................................................................................................................... XVII 5. Introduction .............................................................................................................................. 1 5.1. Aims & Objectives for the Project ................................................................................... 1 5.2. Project Scope .................................................................................................................... 2 5.3. Requirements .................................................................................................................... 2 5.3.1. End user survey ........................................................................................................ 2 6. Chassis Design ......................................................................................................................... 6 6.1. Bench mark chassis .......................................................................................................... 7 6.2. Sandwich panel ................................................................................................................. 8 6.3. Model development and optimisation ............................................................................ 11 6.3.1. Windows ................................................................................................................. 12 6.3.2. Doors ...................................................................................................................... 12 6.3.3. Bogies ..................................................................................................................... 12 6.4. Analysis .......................................................................................................................... 13 6.4.1. Scenarios ................................................................................................................. 13 6.4.2. Torsion .................................................................................................................... 14 6.4.3. Turning ................................................................................................................... 15 6.4.4. Accelerating ............................................................................................................ 16 6.4.5. Bogies ..................................................................................................................... 17 6.4.6. Analysis assumptions and uncertainties ................................................................. 18 6.4.7. Validation ............................................................................................................... 19 6.4.8. Ladder frame .......................................................................................................... 19 6.4.9. Sandwich panels ..................................................................................................... 20 6.5. Aerodynamics ................................................................................................................. 21 6.6. Noise Vibration and Harshness ...................................................................................... 26 6.7. External surfaces ............................................................................................................ 27 Page | IV MDDP Project - Advanced City Bus 2013 6.8. Manufacturing and cost .................................................................................................. 27 6.9. Sustainability .................................................................................................................. 28 6.10. Conclusion .................................................................................................................. 28 7. Drive train .............................................................................................................................