| 摘要 |
PURPOSE:To improve the transitional operability and the emission characteristics by changing nozzle opening period of a fuel injector with a nozzle opening area of the fuel injector maintained at a predetermined value in a low-load region of an internal combustion engine, and maintaining the nozzle opening period at a constant value with the nozzle opening area being increased in medium- and high-load regions. CONSTITUTION:A suction passage 2 of an internal combustion engine 1 is provided with an air flow meter 3 and a throttle sensor 5, and is also provided with fuel injectors 21 for respective cylinders, each injector 21 being controlled to vary a nozzle opening area and a nozzle opening period. The internal combustion engine 1 is provided with a crank angle sensor 8 and a water temperature sensor 9. An exhaust passage 10 is provided with an oxygen sensor 11. Detection signals from the sensors are input to a control unit 12. In a low-load region of the internal combustion engine, the nozzle opening time of each fuel injector 21 is changed with the nozzle opening area maintained at a predetermined value. In medium- and high-load regions, the nozzle opening period is maintained at a constant value in a crank angle period with the nozzle opening area being increased.
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