A More Efficient IC Engine

Tests suggest that a new type of internal combustion engine could be practical and relatively cheap.

Published: 03-Aug-2007

A new version of the internal combustion engine, which could significantly cut gas consumption, might be surprisingly practical and easy to deploy, according to recent findings by researchers at MIT. Tests on a prototype based on the technology, which allows engines to switch between conventional technology and the new gas-saving type of combustion, show that it does not require a special fuel, and engines using the technology can be cheaply made out of conventional auto parts.

The gas-saving technology, called homogeneous charge compression ignition, or HCCI, uses a form of combustion that is much more efficient than conventional spark ignition. Under some conditions, it can reduce fuel consumption by 25 percent, says William Green, a professor of chemical engineering at MIT who was coauthor of the new study. That's very similar to the efficiency of a diesel engine, which also achieves combustion by compression rather than a spark. But unlike diesel engines, HCCI results in a more uniform combustion and is thus much cleaner. A system that combines HCCI with conventional combustion could improve fuel economy by a few miles per gallon on average, Green says.

Several research groups are working on the new type of combustion. Volvo, for example, has built a hybrid system that can switch between conventional spark ignition and HCCI. Some experts, however, had expected that the new type of engine would require special fuel.



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