Diesel Kiki Co., Ltd.

Tomohiko Terada

Hideaki Komada

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 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.

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Higashi Matsuyama, Japan

Tomohiko Terada