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Variable valve timing in a homogenous charge compression ignition engine

United States Patent

August 3, 2004
View the Complete Patent at the US Patent & Trademark Office
The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.
Lawrence; Keith E. (Peoria, IL), Faletti; James J. (Spring Valley, IL), Funke; Steven J. (Princeville, IL), Maloney; Ronald P. (Peoria, IL)
Caterpillar Inc (Peoria, IL)
10/ 029,416
December 20, 2001
GOVERNMENT LICENSE RIGHTS The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of DE-FC05-97OR22605, awarded by the Department of Energy. In other words, this invention was made with Government support under DE-FC05-97OR22605 awarded by the Department of Energy. The Government has certain rights in this invention.