摘要 |
A premixed compression ignition type engine is operated while change over between spark ignition combustion and compression ignition combustion. This engine has a negative overlap period during steady operation under compression ignition combustion. In the same cylinder, a valve-closing timing of an exhaust valve during steady operation under spark ignition combustion is retarded with respect to the valve-closing timing thereof after the change over. In a case where an intake valve is first changed over after start of the change over from spark ignition combustion to compression ignition combustion, the valve-opening timing of the intake valve during a change over period from spark ignition combustion to compression ignition combustion is in an advanced state with respect to the valve-opening timing thereof during steady operation under spark ignition combustion.
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