Nissan Motor Company Limited

Yukiyo Yamada

Kenji Suzuki

Masashi Ono

Ryouichi Ootaki

Tomoki Itou

Hiroshi Takada

An internal-combustion engine includes a variable compression ratio mechanism for changing a mechanical compression ratio, and a variable valve timing mechanism for changing the valve timing of an intake valve. When acceleration is demanded, a target compression ratio is set to a lower compression ratio than the target value in a normal condition, and the valve timing is set to the advance angle side. Since the allowable combustion pressure decreases in a prescribed intermediate compression ratio region, if an actual compression ratio exists in the prescribed intermediate compression ratio region in the course of a compression ratio change accompanying acceleration, the variable compression ratio mechanism restricts the intake pressure by increasing a degree of opening of a wastegate valve or reducing a degree of opening of a throttle valve, for example.

Internal-combustion engine control method and control device

A control method for an internal combustion engine including a variable compression ratio mechanism which includes: implementing a compression ratio fixing control in which a mechanical compression ratio is fixed to a predetermined low compression ratio, and controlling combustion form in a cylinder to stratified combustion, under engine idling during catalyst warming-up; controlling the combustion form in the cylinder to homogeneous combustion, under an operation state other than the engine idling during the catalyst warming-up; and implementing the compression ratio fixing control and controlling the combustion form in the cylinder to the homogeneous combustion, in response to pressing-down of an accelerator under the engine idling during the catalyst warming-up, and as long as the engine idling during the catalyst warming-up has a possibility to resume in response to release of the accelerator after the pressing-down.

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Kanagawa, Japan

Yukiyo Yamada