摘要 |
In a region where the engine load is less than a first predetermined value, only a second exhaust valve that opens and closes a second exhaust passageway that bypasses a turbine of a supercharger is opened. In a region where the engine load is greater than or equal to the first predetermined value and less than a second predetermined value, both the second exhaust valve and a first exhaust valve that opens and closes a first exhaust passageway that leads to the turbine are opened. In a region where the engine load is greater than or equal to the second predetermined value, only the first exhaust valve is opened. A predetermined value for the time of lean combustion is set lower than a predetermined value for the time of stoichiometric combustion.
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