[LEFT]a new engine technology called homogeneous charge compression ignition, or HCCI, that essentially runs a gasoline engine like a diesel.
HCCI uses a sparkless ignition system, relying on compression for fuel combustion. GM officials state “An HCCI engine ignites a mixture of fuel and air by compressing it in the cylinder. Unlike a spark ignition gas engine or diesel engine, HCCI produces a low-temperature, flameless release of energy throughout the entire combustion chamber. All of the fuel in the chamber is burned simultaneously. This produces power similar to today’s conventional gas engines, but uses less fuel to do it.” GM has equipped a Saturn Aura and an Opel Vectra with modified versions of its 2.2L Ecotec four-cylinder engine for testing. GM claims that when this type of engine technology is combined with variable valve timing, direct injection, electric cam phasing, and pressure sensing, it can provide up to a 15% savings in fuel consumption while still meeting future emissions standards.