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As for homogeneous charge compression ignition (HCCI) combustion, many parameters influence on self-ignition timing. We formulated a self-ignition timing simulation model. A control algorithm for HCCI engine has been formulated on the basis of this self-ignition timing simulation model. And the application of the control algorithm to a 4-cylinder engine provided with an electromagnetic valve train demonstrated that it was possible to control HCCI combustion in response to operating conditions. In addition, when switching between spark ignition and HCCI operation, the control algorithm for HCCI engine compensating for the difference in exhaust temperature and the fuel wall-wetting compensating algorithm have enabled switching without torque shock.

Amidst the rising demand to reduce CO2 and other greenhouse gas emissions in recent years, gasoline homogeneous-charge compression ignition (HCCI) has gained attention as a technology that achieves both low NOx emissions and high thermal efficiency by means of lean combustion. However, gasoline HCCI has low robustness toward intracylinder temperature variations, therefore the problems of knocking and misfiring tend to occur during transient operation. The authors verified the transient operation control of HCCI by using a 4-stroke natural aspiration (NA) gasoline engine provided with direct injection (DI) and a variable valve timing and a lift electronic control system (VTEC) for intake air and exhaust optimized for HCCI combustion. This report describes stoichiometry spark ignition (SI) to which external exhaust gas recirculation (EGR) was introduced, HCCI ignition switch control, and changes in the load and number of engine revolutions in the HCCI region.