As part of the transportation arrangements for the Beijing Olympics, 50 hybrid vehicles co-developed with Ricardo are being provided by Chery Automobile Company Ltd. Known as the “Olympics Green Messengers,” these vehicles are some of China’s first hybrid vehicles and will go into full production in the months following the games.
With its expertise in hybrid electric vehicles and its wide-ranging skills in systems integration and vehicle controls and electronics, Ricardo was a natural choice as engineering partner for Chery when the Chinese automaker decided to develop its first hybrid products.
Chery set out to develop two new vehicles based on its existing A5 sedan
The first is a stop-start hybrid based on a 12-volt belt starter-generator (BSG) linked to a 1.6 liter gasoline engine with a 5-speed manual transmission.
The second is a more comprehensive mild hybrid based on the same vehicle but equipped with a 1.3 liter gasoline engine and a 12 kw crankshaft-mounted 151-volt integrated starter-generator (ISG).
These technologies provide significant fuel savings through the use of advanced powertrain control and energy management strategies.
In addition to developing these two new hybrid products, an important objective of the Chery program was technology transfer through integration of the joint program with its own engineering processes.
A dedicated on-site engineering office was established at Ricardo’s Cambridge Technical Centre in the UK.
Chery engineers worked alongside colleagues from Ricardo as well as with selected component and sub-system suppliers to undertake key aspects of the project.
Key Ricardo responsibilities for the BSG program included:
– Full architecture, sub-system and components requirements definition;
– Hybrid control unit design;
– Vehicle and communications interface development;
– System design including detailed thermal analysis;
– Powertrain control strategy for safety and efficient operation.
Thanks to the focus and efficiency of the engineering and development programs, the first prototype vehicle was run with production-intent hardware, complete with hybrid strategy and application software, just ten months from the start of the project. In tests on the ECE Urban drive cycle, the BSG vehicle achieved approximately 7 percent improvement in fuel consumption over the baseline product. Improvements of greater than 10 percent are expected in real-world urban driving.
For the more complex ISG product, Ricardo assumed full system design responsibility, including specification and integration of the ISG system and the high-voltage battery pack and battery management system. Ricardo also 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. The safety-critical application strategies and software were defined, engineered and validated through extensive vehicle and hardware-in-the-loop testing.
With its comprehensive mild-hybrid functionality, the ISG-equipped sedan provides a significant increase in performance over the equivalent baseline A5 vehicle with a 1.3 liter engine.Peak power and torque of the ISG-equipped vehicle are comparable to a 1.6 liter engine. 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 percent compared to the 1.6 liter benchmark vehicle. In addition, the system enables engine restart within 200 milliseconds, thus allowing stop-start functionality to be included in the hybrid control strategy.
The new BSG and ISG powertrain-equipped A5 models of Chery Automobile Co. Ltd. underscore the position of this fast-growing Chinese automaker as one of China’s automotive technology leaders. Engineered to exacting European emissions requirements, these new vehicles are due to enter full production shortly and will be available for both domestic Chinese and export markets.
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