Abstract: A variable discharge high pressure pump for pumping a fuel into a common rail of a common rail type fuel injection system has a plunger reciprocable in a cylinder bore and a pumping chamber defined between and end face of the plunger and the inner peripheral surface of the cylinder bore. A solenoid valve has a valve member movable into an open position in which the valve member is moved out of engagement with an associated valve seat into the pumping chamber when the solenoid valve is deenergized. When the solenoid valve is energized, the valve member is moved into a closed position in which the fuel pressure in the pumping chamber acts on the valve member to urge the same into engagement with the valve seat. The plunger is of a simple cylinderical structure free from any lead formed therein.

Abstract: A variable discharge high pressure pump for pumping a fuel into a common rail of a common rail type fuel injection system has a plunger reciprocable in a cylinder bore and a pumping chamber defined between and end face of the plunger and the inner peripheral surface of the cylinder bore. A solenoid valve has a valve member movable into an open position in which the valve member is moved out of engagement with an associated value seat into the pumping chamber when the solenoid valve is deenergized. When the solenoid valve is energized, the valve member is moved into a closed position in which the fuel pressure in the pumping chamber acts on the valve member to urge the same into engagement with the valve seat. The plunger is of a simple cylindrical structure free from any lead formed therein.

Abstract: Engine speed is controlled during gear change by way of both fuel supply apparatus and exhaust brake so that engine speed is equal to the rotational speed of an input shaft of a transmission coupled via a clutch to the engine. When the engine speed is higher than the rotational speed of the transmission input shaft, exhaust braking is performed to quickly reduce the engine speed thereby establishing synchronization. Then the fuel supply apparatus is controlled to reduce the amount of fuel for maintaining the decreased engine speed. On the other hand, when the engine speed is lower than the rotational speed of said transmission input shaft, only the fuel supply apparatus is controlled to increase the fuel amount. Engine braking is performed only when the clutch is in disconnected state, and therefore, vehicle speed is not decelerated due to the engine braking.

Abstract: A fuel injection arrangement for a diesel engine. An overflow passage for high pressure fuel is provided in the engine's fuel injection pump. A solenoid valve is disposed in the overflow passage for controlling the fuel injection amount through its on-off operation. The time when the fuel injection pump starts injecting fuel is detected by an injection start detector. To this injection starting time point is added a target injection period to determine an injection end time. At this injection end time the solenoid valve is opened to discontinue the fuel injection. The target injection period is determined according to operating conditions of the engine. Since this apparatus detects the actual injection start point and controls the injection period on the basis of the result of the detection, the fuel injection amount can be controlled extremely accurately.

Abstract: An optimum control method for internal combustion engines uses the values of an engine control variable, such as engine timing, which are arranged in a map and stored in a memory. During normal operation, the engine is operated in accordance with one of the mapped engine control variable values related to engine operating conditions. During a fuel consumption minimization operation, the mapped engine control variable value is changed by an incremented amount to operate the engine therewith, and the mapped engine control variable value is replaced by the changed engine control variable value, if it is detected that the change by the incremented amount is in a direction to reduce the fuel consumption rate of the engine. This optimum engine control method can compensate for changes in the characteristics of engines caused during the manufacture or caused by changes over time during their operation, thereby ensuring the operation of an engine at a minimum rate of fuel consumption.