Beijing Olympics bow for hybrid vehicles
As a part of the transportation arrangements for the Beijing Olympics, a 50-unit fleet of hybrid vehicles co-developed with Ricardo plc with input from its Cambridge R & D hub, is being provided by Chery Automobile Company Ltd.
Known as the Olympics Green Messengers, these vehicles are some of China’s first hybrid vehicles and go into full production in the months following the Games. With its expertise in hybrid electric vehicles and wide-ranging skills in systems integration and vehicle control and electronics, Ricardo was a natural choice of engineering partner for Chery when the Chinese automaker decided to develop its first hybrid products. Two new vehicles, both based on its existing A5 sedan model, were identified. The first is a stop-start hybrid based on a 12-volt Belt Starter-Generator (BSG) linked to 1.6 litre gasoline engine, itself linked to a 5-speed manual transmission. The second is a more comprehensive mild-hybrid based on the same baseline vehicle but equipped with a 1.3 litre gasoline engine and a 12 kW crankshaft-mounted 151-volt Integrated Starter-Generator (ISG). These technologies have been configured to be capable of providing significant fuel savings through the use of advanced powertrain control and energy management strategies. In addition to developing the new products, an important objective was technology transfer through integration of the joint programmes with Chery’s own engineering processes. A dedicated on-site engineering office was therefore established at the Ricardo Cambridge technical centre. Chery engineers were able to work alongside colleagues from Ricardo and selected component and sub-system suppliers. Key Ricardo responsibilities for the BSG programme included full architecture, sub-system and components requirements definition, hybrid control unit design, vehicle and communications interface development, system design – including detailed thermal analysis - and powertrain control strategy for safety and efficient operation. The first prototype vehicle was run with production-intent hardware and complete with hybrid strategy and application software, just 10 months from programme start. The final fuel economy results are no less impressive: In tests over the ECE urban drive cycle, the BSG vehicle achieves a 7 per cent improvement in fuel consumption over the baseline product; it is expected that the improvement will be greater than 10 per cent in real-world urban driving. For the more complex ISG product, Ricardo carried full system design authority including specification and integration of the ISG system, high-voltage battery pack and battery management system, and developed an integrated hybrid control unit that incorporates the motor drive power electronics, DC to DC converter, and hybrid supervisory and safety functions into one compact package. Final production calibration and testing of the vehicle systems are still taking place, but the fuel consumption improvement over the NEDC cycle is expected to approach 15 per cent compared to the 1.6 litre benchmark vehicle. In addition, the system enables engine restart within 200 milliseconds, allowing stop-start functionality to be included in the hybrid control strategy. The new vehicles will enter full production soon and be available for Chinese and export markets.