SPARK IGNITION TYPE INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To switch an air-fuel ratio without causing torque fluctuation. SOLUTION: This spark ignition type internal combustion engine comprises a variable compression ratio mechanism A capable of changing mechanical compression ratio and a variable valve timing mechanism B capable of controlling the valve-opening timing of an intake valve 7. The intake air amount supplied into a combustion chamber 5 is controlled by changing the valve-closing timing of the intake valve 7. When the air-fuel ratio is changed from a theoretical air-fuel ratio to a target lean air-fuel ratio, the valve-closing timing of the intake valve 7 is spark-advanced until the air-fuel ratio reaches the target lean air-fuel ratio without changing a fuel injection amount. COPYRIGHT: (C)2009,JPO&INPIT