Peace-of-Mind Series Hybrid Electric Vehicle Drivetrain

Doerffel, Dennis (2003); MPhil/PhD - Transfer Thesis - Southampton, UK, University of Southampton, School of Engineering Sciences, 118pp.

This study investigates a new series hybrid electric drivetrain concept for on-road vehicles in order to find a means of sustainable individual transport without decreasing quality of life for anybody and without putting the burden of high investments on future generations. The concept called Peace-of-Mind is based on existing technology and promises:
Noticeable contribution to lower CO2 emissions and less energy consumption.

• Improvements for local air quality in urban areas.
• Some improvements in other environmental impacts like noise or emissions.
• Fuel and energy supply within the existing infrastructure.
• Fuel-flexibility - that means the drivetrain can easily be adapted to other fuels without a complete new design.
• Ease of technology changes and improvements - that means new technologies (fuel cell) can be implemented without major redesigns.
• Near-term market introduction through mainly employing available technology.
• Affordability and desirability.

This thesis begins with a review of actual vehicle design considerations, energy considerations and technology considerations including battery issues.
The lithium-ion battery is a vital part of this concept and many other possible future car concepts. A new test procedure is proposed and the test-results are used for developing a new battery model.

The new series hybrid electric drivetrain concept is specified based on knowledge about available products and using fundamental equations for propulsion. The specified drivetrain is compared with existing vehicles using ADVISOR, a Matlab-based simulation package for drivetrains.

The drivetrain management requirements for this concept are discussed and the hardware for this management and in-vehicle data-acquisition is described.
The simulation results indicate that the proposed drivetrain concept is viable: the energy consumption is very low, it produces no local pollution in urban traffic, the performance is acceptable and the versatility of the car is comparable with actual vehicles. But simulation and first driving results also indicate that the battery is the key issue: it adds substantial cost, weight and uncertain behaviour.

The thesis concludes with suggestions for future work: A field-test with about ten vehicles will reveal cutting-edge knowledge on the changes of battery behaviour over their lifetime. The new battery model will be used to determine the battery behaviour.

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