| 摘要 |
PROBLEM TO BE SOLVED: To prevent a pumping loss from occurring when an expansion ratio is high. SOLUTION: The spark ignition type internal combustion engine includes a variable compression ratio mechanism A capable of changing a mechanical compression ratio and a variable valve timing mechanism C capable of controlling the opening timing of an exhaust valve 9. During the low-load operation of the engine, the mechanical compression ratio is made maximum in order to obtain a maximum expansion ratio. In the latter half of an expansion stroke at that time, the opening timing EO of the exhaust valve 9 is advanced so that pressure P in a cylinder does not become equal to or lower than the atmospheric pressure PX. COPYRIGHT: (C)2008,JPO&INPIT
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