| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark ignition internal combustion engine capable of maintaining a temperature of an emission control catalyst relatively high even when the internal combustion engine is operated under a state where the expansion ratio is high. SOLUTION: The spark ignition internal combustion engine includes: a variable compression ratio mechanism A capable of changing a mechanical compression ratio; a mechanism B for changing an actual compression action starting time capable of changing the starting time of an actual compression action; and an exhaust valve 9. During a low load operation of engine, the mechanical compression ratio is set at a maximum so as to obtain a maximum expansion ratio, the actual compression ratio is set so as to prevent knocking, and the maximum expansion ratio is 20 or more. Furthermore, during a low load operation of engine, closing time of the exhaust valve is made to correspond to approximately an intake top dead center. COPYRIGHT: (C)2008,JPO&INPIT
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