Diesel Kiki Co., Ltd.

Hideaki Komada

Tomohiko Terada

Tomonori Ohie

Yutaka Kojima

Shojiro Otsuka

A multistage fuel injection system for an internal combustion engine has an injection nozzle capable of injecting main and auxiliary fuels into a cylinder of the engine at controlled intervals, thereby completely combusting an unburned fuel-and-air mixture in the cylinder. The injection nozzle includes a main injection passage for the main fuel, a needle valve for opening and closing the main injection passage, an auxiliary injection passage for the auxiliary fuel communicating with the main injection passage through the needle valve at a discharge end of the latter, and a check valve for preventing a reverse flow of the main fuel from the main injection passage to the auxiliary injection passage.

Multistage fuel injection system for internal combustion engines

A fuel injection system includes a booster for intensifying a supply of fuel from a fuel reservoir and a nozzle needle actuator for operating a fuel injector to start and terminate a fuel injection from the latter. The boosted fuel from the booster is fed not only to the fuel injector but to an upper chamber of the nozzle needle actuator which is defined by a piston. A first hydraulic circuit produces a variable hydraulic fluid pressure for operating the booster in accordance with a predetermined engine operating parameter. A lower chamber also defined by the piston in the nozzle needle actuator is selectively communicated to the first hydraulic circuit by a second hydraulic circuit. The first and second hydraulic circuits share a common source of hydraulic fluid supply which is independent of the fuel reservoir.

Fuel injection system

A fuel injector of a Diesel engine is supplied with a boosted supply of fuel from a booster and operated to start and terminate a fuel injection by a hydraulically controlled nozzle needle actuator. A valving unit is controlled to selectively communicate compressed operating fluid to the booster so that the boosted supply of fuel reaches the fuel injector. The valving unit comprises a pair of poppet type valves each of which is operated by a solenoid operated pilot valve, thereby attaining high speed operation due to a high frequency of switching actions and accommodating a large flow rate of fluid. A manually or automatically adjustable stop is associated with each of the poppet type valves to control the flow rate of fluid through the valve to the booster, which dictates the pressure of fuel injection from the injector.

A fuel injection system has a fuel supply line which extends from a fuel reservoir to a fuel injector through a booster and is hydraulically isolated from a hydraulic circuit for operating the booster and a hydraulic circuit for operating a nozzle needle actuator, which is operatively associated with the fuel injector to control fuel injection. The two hydraulic circuits share a common source of hydraulic fluid supply which is independent of the fuel reservoir and adapted to actuate general hydraulic units. An electronically operated pressure control valve is controlled by a control unit to drive the booster with a hydraulic fluid pressure which varies in proportion to a varying engine load, i.e. full load, partial load and no load.

Growing community of inventors

Higashi Matsuyama, Japan

Hideaki Komada