Abstract: At abnormal pressure pulsation generating time, a piston of a pulsation reducing apparatus is displaced in a valve chamber due to an increase in a fuel pressure in an upstream side fuel passage, so that fluid communication between a valve chamber and a downstream side fuel passage is disabled, and fluid communication between a valve chamber side end part of a return passage and the valve chamber is enabled. Pressure pulsation is conducted into the return passage and is reduced by a damping effect of a pulsation reducing mechanism and a flow restricting effect of orifices. The fuel, which has passed through the orifices, is returned to the upstream side fuel passage through the return passage.

Abstract: At abnormal pressure pulsation generating time, a piston of a pulsation reducing apparatus is displaced in a valve chamber due to an increase in a fuel pressure in an upstream side fuel passage, so that fluid communication between a valve chamber and a downstream side fuel passage is disabled, and fluid communication between a valve chamber side end part of a return passage and the valve chamber is enabled. Pressure pulsation is conducted into the return passage and is reduced by a damping effect of a pulsation reducing mechanism and a flow restricting effect of orifices. The fuel, which has passed through the orifices, is returned to the upstream side fuel passage through the return passage.

Abstract: An injection quantity control unit controls an injection quantity of a plurality of fuel injection valves, respectively. The unit includes a rotational speed obtaining device for obtaining a rotational speed of the engine, an integration value calculating device for calculating an integration value of the rotational speed, which is equal to or more than a predetermined rotational speed, in an explosion stroke of each of the cylinders, and a correcting device for correcting the injection quantity of the plurality of fuel injection valves based on the integration value of each of the cylinders so as to reduce variation in a rotational speed variation among the cylinders.

Abstract: An injection quantity control unit controls an injection quantity of a plurality of fuel injection valves, respectively. The unit includes a rotational speed obtaining device for obtaining a rotational speed of the engine, an integration value calculating device for calculating an integration value of the rotational speed, which is equal to or more than a predetermined rotational speed, in an explosion stroke of each of the cylinders, and a correcting device for correcting the injection quantity of the plurality of fuel injection valves based on the integration value of each of the cylinders so as to reduce variation in a rotational speed variation among the cylinders.

Abstract: A fuel injection controller of a diesel engine calculates a requirement injection amount based on an operation amount of an accelerator pedal and rotation speed of the engine. The fuel injection controller divides the requirement injection amount into multiple injections. Injection amounts of the divided injections are set to monotonically increase with respect to an order of the injections. Thus, even if a simple fuel injection device is used, the fuel injection controller can suitably achieve both of reduction of a discharge amount of nitrogen oxides and reduction of fuel consumption.

Abstract: A pressure pattern estimation device of a fuel injection controller of an engine estimates a pressure transition of fuel in a common rail. A surplus pressure range calculation device of the fuel injection controller calculates a surplus pressure range in which pressure pattern data provided by the pressure pattern estimation device exceeds a target common rail pressure. The fuel injection controller releases the common rail pressure to a lower-pressure side by operating a pressure reduction valve of the common rail to eliminate the surplus pressure range calculated by the surplus pressure range calculation device. Thus, the common rail pressure (injection pressure) during an injection period is smoothed.

Abstract: A pressure pattern estimation device of a fuel injection controller of an engine estimates a pressure transition of fuel in a common rail. A surplus pressure range calculation device of the fuel injection controller calculates a surplus pressure range in which pressure pattern data provided by the pressure pattern estimation device exceeds a target common rail pressure. The fuel injection controller releases the common rail pressure to a lower-pressure side by operating a pressure reduction valve of the common rail to eliminate the surplus pressure range calculated by the surplus pressure range calculation device. Thus, the common rail pressure (injection pressure) during an injection period is smoothed.

Abstract: An engine control unit (ECU) monitors an idling rotation speed of a diesel engine and predicts a tendency of an increase in an injection quantity occurring until an increasing rate of the injection quantity converges based on an initial tendency of an increase in the idling rotation speed. If the idling rotation speed exceeds a predetermined reference rotation speed, the ECU performs correction (counter control) for reducing the injection quantity. Thus, an increase in the injection quantity due to changes in hardware with time can be eluded, and an increase in an engine output due to the increase in the injection quantity can be inhibited. Therefore, damages to the diesel engine due to an excessive increase in the engine output can be prevented.

Abstract: An engine control unit (ECU) monitors an idling rotation speed of a diesel engine and predicts a tendency of an increase in an injection quantity occurring until an increasing rate of the injection quantity converges based on an initial tendency of an increase in the idling rotation speed. If the idling rotation speed exceeds a predetermined reference rotation speed, the ECU performs correction (counter control) for reducing the injection quantity. Thus, an increase in the injection quantity due to changes in hardware with time can be eluded, and an increase in an engine output due to the increase in the injection quantity can be inhibited. Therefore, damages to the diesel engine due to an excessive increase in the engine output can be prevented.

Abstract: A fuel injection system for an internal combustion engine includes a fuel injection pump injecting a fuel in an amount corresponding to a position of a control rack, a governor including a start spring, a control spring and an idling sub-spring biasing the control rack in a fuel injection amount increasing direction, an adjusting lever adjusting a spring load of the control spring, and a fly weight rotating together with the fuel injection pump and shifting the control rack in a fuel injection amount decreasing direction by a centrifugal force, and a stopper mechanism restricting movement of the control rack in the fuel injection amount increasing direction, wherein the stopper mechanism comprising a stopper opposing to an end portion of the control rack and an elastic body biasing and holding the stopper at a stop position, an elastic force of the elastic body being set to be greater than a sum of a spring load of the start spring and a spring load of the idling sub-spring while the adjusting lever is in an