US 5,682,858 A · Hydraulically-actuated fuel injector with pressure spike relief valve

Abstract

A hydraulically-actuated fuel injector includes an injector body having a nozzle chamber, a nozzle outlet, an actuation fluid inlet, an actuation fluid drain, an actuation fluid cavity and a pressure relief passage extending between the actuation fluid cavity and the actuation fluid drain. A hydraulic means, including an actuation fluid control valve mounted within the injector body, is used for pressurizing fuel in the nozzle chamber. A needle valve member is mounted to reciprocate in the nozzle chamber between an open position in which the nozzle outlet is open and a closed position in which the nozzle outlet is closed. A relief valve is mounted within the injector body and has a first position in which the pressure relief passage is closed and a second position in which the pressure relief passage is open.

Claims20

Dependent claims

A hydraulically actuated fuel injector comprising:

an injector body having an actuation fluid cavity, a needle control chamber, a nozzle chamber and a nozzle outlet that opens to said nozzle chamber;
hydraulic means, within said injector body, for pressurizing fuel in said nozzle chamber;
a needle valve member positioned to reciprocate in said nozzle chamber between an opened position in which said nozzle outlet is open and a closed position in which said nozzle outlet is closed, said needle valve member including a closing hydraulic surface exposed to pressure in said needle control chamber;
a needle control valve mounted within said injector body, and being movable between an off position in which said needle control chamber is opened to a source of high pressure fluid and an on position in which said needle control chamber is opened to a low pressure passage;
and
means, within said injector body, for venting post injection pressure from said actuation fluid cavity.

3 more elements

A hydraulically actuated fuel injector comprising:

an injector body having a nozzle chamber, a nozzle outlet, an actuation fluid inlet, an actuation fluid drain, an actuation fluid cavity and a pressure relief passage extending between said actuation fluid cavity and said actuation fluid drain;
hydraulic means, including an actuation fluid control valve mounted within said injector body, for pressurizing fuel in said nozzle chamber;
a needle valve member mounted to reciprocate in said nozzle chamber between an open position in which said nozzle outlet is open and a closed position in which said nozzle outlet is closed;
a relief valve mounted within said injector body and having a first position in which said pressure relief passage is closed and a second position in which said pressure relief passage is open.

1 more element

Dependencies are inferred from the claim text.

Hydraulically-actuated fuel injector with pressure spike relief valve

Life of this patent

Hydraulically-actuated fuel injector with pressure spike relief valve

Life of this patent

Abstract

Claims20