US 5,669,355 A · Hydraulically-actuated fuel injector with direct control needle valve

Abstract

A hydraulically actuated fuel injector includes an injector body having at least one actuation fluid inlet, a needle control chamber, a nozzle chamber, and a nozzle outlet that opens to the nozzle chamber. A hydraulic means within the injector pressurizes fuel in the nozzle chamber. The hydraulic means includes an actuation fluid control valve having a first solenoid and is moveable between an open position in which the actuation fluid inlet is open and a closed position in which the actuation fluid inlet is closed. A needle valve member is positioned 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 needle valve member includes a closing hydraulic surface exposed to pressure in the needle control chamber. A needle control valve having a second solenoid is mounted within the injector body and is moveable between an off position in which the needle control chamber is opened to a source of high pressure fluid and an on position in which the needle control chamber is opened to a low pressure passage.

Claims20

Dependent claims

A hydraulically actuated fuel injector comprising:

an injector body having at least one actuation fluid inlet, a needle control chamber, a nozzle chamber and a nozzle outlet that opens to said nozzle chamber;
hydraulic means, within said injector, for pressurizing fuel in said nozzle chamber, said hydraulic means including an actuation fluid control valve having a first solenoid and being movable between an open position in which said at least one actuation fluid inlet is open and a closed position in which said actuation fluid inlet is closed;
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 having a second solenoid 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.

1 more element

A fuel injection system comprising:

a plurality of hydraulically actuated fuel injectors with direct control needle valves, each injector having hydraulic means for pressurizing fuel that includes an actuation fluid control valve with a first solenoid, a needle valve member with a closing hydraulic surface exposed to pressure in a needle control chamber and a needle control valve with a second solenoid that alternately opens said needle control chamber to a source of high pressure fluid or a low pressure passage, and each injector also having an actuation fluid inlet, an actuation fluid drain and a fuel supply passage;
a source of fuel connected to said fuel supply passage of each said injector;
a source of high pressure actuation fluid connected to said actuation fluid inlet;
a low pressure reservoir connected to said actuation fluid drain;
and
a computer in communication with and capable of independently controlling said needle control valve and said actuation fluid control valve.

3 more elements

Dependencies are inferred from the claim text.

Hydraulically-actuated fuel injector with direct control needle valve

Life of this patent

Hydraulically-actuated fuel injector with direct control needle valve

Life of this patent

Abstract

Claims20