Abstract: A fuel injector includes a pressure chamber and/or a damper chamber to damp the movement of a plunger and a piston after fuel injection has ended. A fuel bypass communicates with the pressure chamber or damper chamber to prevent fuel pressure within the chamber from rising as a consequence of the damping action. The bypass prevents the pressure in the chamber from increasing to the point where the movement of the plunger would be reversed and pressurized fuel would once again be supplied to the nozzle causing secondary injection. The damper chamber and bypass thus serve to prevent bumping between the plunger and the surrounding cylinder and also to prevent secondary injection.

Abstract: A distributor-type fuel injection pump for an internal combustion engine wherein the plunger has first and second portions with different diameters from each other, defining first and second pump working chambers, respectively. A communication passageway is arranged for communicating the second pump working chamber with fuel delivery passageways leading to respective fuel injection valves of the engine. A drain passageway is arranged for communicating the communication passageway with a zone under a lower pressure of the pump, and is selectively closed and opened by a selector valve. An electronic control unit is responsive to operating conditions of the engine for driving the selector valve to selectively assume closed and open positions. Fuel is pressure delivered to the fuel injection valves from one or both of the first and second pump working chambers, depending upon whether the selector valve assumes the closed position or the open position.

Abstract: A communication passage connects a first fuel passage connected to a fuel injection valve of a multi-cylinder internal combustion engine corresponding to a cylinder which is to be fired earlier, to a second fuel passage connected to a fuel injection valve corresponding to another cylinder which is to be fired later, at locations in the vicinity of the outlet ports of corresponding delivery valves arranged across the respective fuel passages. A selector valve selectively connects the delivery valve in the first fuel passage with the fuel injection valve corresponding to the first fuel passage or with the communication passage, so that when the engine is operating in a low load and low speed region, part of the cylinder alone is operated and at the same time fuel is allowed to flow in a sole direction from the first fuel passage to the second fuel passage via a one-way valve, to thereby effect a VIGOM injection.

Abstract: A distributor-type fuel injection pump for internal combustion engines includes an injection timing control device operatively connecting to a plunger and actuatable in response to the pressure within a fuel chamber in the pump housing, the plunger having a main discharge port and a preliminary discharge port for a preliminary fuel injection in advance of the next following main injection. The control device has a first member actuatable in response to the pressure within the fuel chamber for effecting a preliminary fuel injection when the pressure is at less than a predetermined value, and has a second member actuatable in response to the pressure with the fuel chamber for preventing the preliminary fuel injection when the pressure is above the predetermined value. Preferably, the predetermined pressure value corresponds to an idling speed of the engine.

Abstract: A fuel injection valve for an internal combustion engine, in which a lift-limiting plunger is slidably fitted in a plunger chamber to receive fuel pressure for limiting the lifting amount of a nozzle needle. A back pressure chamber is defined by an end face of the plunger remote from the nozzle needle as part of the plunger chamber. A selector valve is controlled by an electronic control unit to establish communication between the back pressure chamber and a fuel intake passageway during low speed/low load operation of the engine, whereby the nozzle needle is lifted through a limited stroke to obtain a reduced fuel injection rate as well as a prolonged fuel injection period. A pressure inlet chamber permanently communicates with the back pressure chamber and is selectively communicated with the fuel intake passageway and disconnected therefrom by the selector valve, in synchronism with selective establishment and interruption of communication between the back pressure chamber and the fuel intake passageway.

Abstract: A piston is rotatably received within a piston chamber formed in the nozzle holder for lifting together with the nozzle needle. An oil passage opens in the piston chamber in a manner closable by the lifting piston. After the closure of the oil passage, the lifting piston cooperates with the piston chamber to define a confined space whereby further lifting of the piston is prohibited. The piston remote from the nozzle needle has an end face thereof so configurated that the piston lifts through a stroke variable as the piston varies in circumferential position, from the time the nozzle needle starts lifting to the time the piston closes the oil passage. Preferably, the circumferential position of the piston is controlled by rotating means which rotates the piston in response to at least one parameter indicative of the operation of the engine.