GM today introduced the combustion process formally known as homogeneous charge compression ignition, or HCCI, for the first time in two drivable concept cars. GM has fitted the 2007 Saturn Aura and the Opel Vectra with HCCI which provides up to 15 percent fuel savings while meeting future emissions standards.
Virtually the engines burn gasoline in the same way that a diesel engine burns diesel fuel. To do this the process is combined with advanced technologies, direct injection, electric cam phasing, variable valve lift and cylinder pressure sensing....
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