| 摘要 |
PROBLEM TO BE SOLVED: To reduce fuel consumption in a lean-burn state, and also to secure stability of an engine in an idling and trawling state. SOLUTION: An engine control unit of a ship propulsion system is provided with an intake pressure detecting means for detecting intake pressure, a throttle opening detecting means for detecting throttle opening, and an engine rotational speed detecting means for detecting rotational speed of an engine, and controls fuel injection quantity based on the intake pressure, the throttle opening, and the rotational speed of the engine. In a very light load region from a fully closed state to a required opening of the throttle, the fuel injection quantity is controlled so that a predetermined air-fuel ratio is obtained. In a region from the required opening to a required intake pressure before almost constant intake pressure, the fuel injection quantity is controlled based on the throttle opening. In a region from the required intake pressure to the almost constant intake pressure, the fuel injection quantity is controlled by gradually adjusting it so that the air-fuel ratio almost becomes the lean mixture limit. In a region where the intake pressure does not change even when the throttle is opened, the fuel injection quantity is controlled based on the throttle opening and the rotational speed of the engine.
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