| 摘要 |
PURPOSE:To limit a rotational speed of a Diesel engine to a permissible speed or less without interfering with another injection quantity control, by reducing a fuel injection rate when the rotational speed of the engine becomes greater than a predetermined value. CONSTITUTION:An engine speed sensor 70 detects a rotational speed of a Diesel engine 1 to feed the same to an electronic control circuit 40. When the engine speed exceeds a permissible speed, the electronic control circuit 40 reduces current flowing in a coil 36 of an injection pressure control solenoid valve 30. As a result, a fuel injection pressure is reduced, and a fuel injection rate is therefore reduced, thereby reducing the engine speed. Thus, the fuel injection rate may be reduced so that the engine speed of the Diesel engine 1 may not exceed the permissible speed, independently of fuel injection quantity control, that is, control of a spill ring 54. Accordingly, the engine speed control may be carried out without interfering with the injection quantity control. Further, in the case of adjusting a maximum injection quantity by providing an intake air pressure sensor 82 or the like, abnormality may be avoided.
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