August 17, 2005

GM, Bosch and Stanford team up to improve engines

Palo Alto, California – General Motors, the Robert Bosch Corporation and Stanford University are developing a cost-effective engine technology that makes gasoline engines more efficient and diesel engines much cleaner, for use in both conventional and hybrid systems.

Under a three-year, US$2.5 million program, researchers from the three partners will work to accelerate the development of Homogeneous Charge Compression Ignition, or HCCI, a research technology with the potential to dramatically improve the efficiency of gasoline and hybrid systems by burning fuel more efficiently. HCCI can help improve gasoline fuel efficiency by 20 per cent, while achieving near-zero oxide of nitrogen (NOx) emissions and particulates.

In the HCCI engine, fuel is uniformly mixed with air, as in a spark-ignition engine, but with a higher proportion of air to fuel. Rather than using a spark plug to ignite the mixture, it is compressed by the piston until rising temperatures inside the chamber ignite it spontaneously, a process similar to that of a diesel engine but at a much lower temperature. This leads to a significant boost in fuel economy.

Controlling HCCI combustion in a real-world environment, versus the lab, is a major hurdle for its commercialization. The Bosch Group has already been working an advanced system technology for HCCI combustion control; in the same timeframe, GM’s global research and development team, in cooperation with other universities and suppliers, has developed a concept that allows the operation of HCCI over a broad engine speed and load range. Under the joint program, GM will explore the potential commercial implementation, while Bosch will work to develop the technologies critical to the manufacture of key HCCI sensors and actuators.

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