To reduce emission of unburned fuel during an engine cool down period by reducing fuel spray which interferes with intake valves 5A and 5B during intake stroke injection when injecting fuel from a fuel injection valve 7 placed beside a combustion chamber 1 toward the center of the combustion chamber 1 through between the two intake valves 5A and 5B.

In the homogeneous combustion mode which injects fuel on the intake stroke and during the engine cool down period, one intake valve 5A is kept closed so that the fuel spray interferes with one intake valve (5B) only. The operation with one valve closed is performed in the low load (low torque) region, and a tumble control valve 9 is actuated at the same time so as to enhance in-cylinder flow.

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