Fuel injector having fuel plunger with energized sealing element and method
AssigneeCaterpillar Inc.
InventorsSteven D. Wehri, Eric L. Rogers, Christopher R. Jones
Life of this patent
Estimating the term…
Abstract
A fuel injector in an internal combustion engine system includes an injector housing, and a fuel plunger within the injector housing. A clearance is defined between the fuel plunger and the injector housing. The fuel plunger includes a sealing element between the fuel plunger and the injector housing and fluidly sealing the clearance. The fuel injector may be applied in alternative fuel applications limiting migration of fuel from a plunger cavity in the injector housing into other parts of an engine, such as an engine oil system.
Claims20
A fuel injector comprising:
- an injector housing including a nozzle having a plurality of spray orifices formed therein, an injection valve movable to open and close the plurality of spray orifices, and a fuel plunger;
- the fuel plunger including a first, actuated end, and a second, pumping end, and a clearance is defined between the second, pumping end and the injector housing;
- and
- a sealing element held in compression between the second, pumping end of the fuel plunger and the injector housing and fluidly sealing the clearance.
A fuel plunger for a fuel injector comprising:
- an elongate plunger body defining a longitudinal axis extending between a first, actuated end, and a second, pumping end;
- the first, actuated end including an enlarged upper head having a planar tappet-contact end surface, and the second, pumping end including an enlarged lower head having a second end surface, and the elongate plunger body including a necked-down section extending from the enlarged upper head to the enlarged lower head;
- the enlarged lower head having an annular distal head portion including the second end surface, and an annular inward head portion;
- and
- a seal groove is formed axially between the annular distal head portion and the annular inward head portion and extends circumferentially around the longitudinal axis.
A method of operating a fuel injector comprising:
- advancing a fuel plunger in a fuel injector toward an advanced position in response to rotation of a cam;
- pressurizing a fuel to an injection pressure in a plunger cavity in the fuel injector based on the advancing of the fuel plunger;
- biasing a sealing element carried on the fuel plunger outwardly into sealing contact with an injector housing of the fuel injector during the advancing of the fuel plunger;
- and
- limiting migration of pressurized fuel through a clearance defined between the fuel plunger and the injector housing based on the sealing contact.
Dependencies are inferred from the claim text.