Fuel injector in an engine having spray orifice set configured for offset positioning and engine operating method
AssigneeCaterpillar Inc.
InventorsBobby John, Jonathan W. Anders
Life of this patent
Estimating the term…
Abstract
An engine includes a piston movable in a cylinder and having a combustion bowl, and an annular rim forming a scoop extending axisymmetrically around a piston center axis. A fuel injector tip extends into the cylinder and includes a first orifice set and a second orifice set offset from one another and offset from the piston center axis. A plurality of orifice-rim distances are defined between orifices in the second orifice set and an annular rim of the piston. The orifices in the second orifice set having a range of orifice sizes varied in direct relation to the respective orifice-rim distances. Related methodology is also disclosed.
Claims20
An engine comprising:
- an engine housing having a cylinder formed therein;
- a piston movable in the cylinder and including a combustion bowl, and an annular rim extending circumferentially around the combustion bowl and defining a piston center axis;
- a fuel injector tip including a first orifice set having a plurality of orifices arranged in a first targeting pattern within the cylinder and distributed around a first tip axis, and a second orifice set having a plurality of orifices arranged in a second targeting pattern and distributed around a second tip axis;
- the second tip axis is offset from the piston center axis, such that a plurality of orifice-rim distances are defined, in a projection plane normal to the piston center axis, between the plurality of orifices in the second orifice set and the annular rim;
- and
- the plurality of orifices in the second orifice set having a range of orifice sizes that is varied in direct relation to the respective orifice-rim distances.
A method of operating an engine comprising:
- moving a piston defining a piston center axis toward a top-dead-center position in a cylinder in an engine;
- injecting a first shot of a liquid fuel into the cylinder from a secondary orifice set, in a fuel injector tip, offset from the piston center axis;
- advancing spray jets of the first shot through the cylinder according to a targeting pattern that is based on an arrangement of the secondary orifice set in the fuel injector tip, and according to a penetration pattern that is based on a varied size of orifices in the secondary orifice set;
- injecting a second shot of a liquid fuel into the cylinder from a main orifice set, in the fuel injector tip;
- advancing spray jets of the second shot through the cylinder;
- and
- compression igniting the liquid fuel of the first shot and the second shot in the cylinder.
A fuel injector comprising:
- a nozzle including an injector tip having a main tip portion and a secondary tip portion, a main orifice set formed in the main tip portion, and a secondary orifice set formed in the secondary tip portion;
- the nozzle further having formed therein at least one liquid fuel supply passage extending to the main orifice set and to the secondary orifice set;
- the main tip portion defining a first tip axis, and the secondary tip portion defining a second tip axis that is offset from the first tip axis;
- the main orifice set including a plurality of orifices arranged in a first targeting pattern around the first tip axis, and the secondary orifice set including a plurality of orifices arranged in a second targeting pattern around the second tip axis;
- the plurality of orifices in the secondary orifice set having a range of spray angles, and a range of orifice sizes that varies in direct relation to the respective spray angles.
Dependencies are inferred from the claim text.