| 摘要 |
PURPOSE:To compensate a decrease of compression ratio when an intake timing control valve is early closed, by controlling the intake timing in accordance with an engine operative condition through the intake timing control valve, provided just in the upstream of an intake valve, while providing a compression ratio changing means in a combustion chamber. CONSTITUTION:A rotary type intake control valve 2, which rotates interlocking to an engine, is provided just in the upstream of an intake valve 1 in an intake port IP, and the engine constitutes the intake control valve 2 so as to close the intake port prior to closing of the intake valve 1 when the engine is in low load operation. The engine, arranging in its combustion chamber 12 a piston 14 loaded by a spring 15, variably forms volume of a subcombustion chamber 13. The earlier is the closing timing of the intake control valve 2, the smaller compression ratio in the combustion chamber 12 tends to decrease, but the engine, extruding the piston 14 by the spring 15 to decrease a capacity of the subcombustion chamber when the compression ratio decreases small, decreases the whole volume of the combustion chamber, thus a decrease of the compression ratio can be prevented.
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