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US 2011/0253105 A1Published application
Fluid injector with back end rate shaping capability
AssigneeCaterpillar Inc.
InventorsHoisan Kim, Mark F. Sommars
Life of this patent
Estimating the term…
Abstract
A common rail single fluid injection system includes fuel injectors ramp shaped injection curves at both the front and back ends of an injection event. This is accomplished by including a check speed control device fixed in position within the check control chamber of a fuel injector. The check speed control device controls the speed of a check by restricting fuel flowing into and out of the check control chamber.
Claims20
A fuel injector comprising:
- an injector body defining a high pressure inlet, a nozzle supply passage, a check control chamber, a check control line, a low pressure drain and at least one nozzle outlet;
- a check speed control device fixedly positioned within the check control chamber and having an upper bowl, a lower bowl and at least one orifice through the lower bowl;
- a control valve assembly having a valve member configured to selectively allow fluid communication from the upper bowl and check control line to the low pressure drain;
- and
- a check needle movable within the injector body between a first position at which the check needle blocks the at least one nozzle outlet and a second position at which the check needle at least partially opens the at least one nozzle outlet,
- the check needle including at least one opening hydraulic surface exposed to a fluid pressure of the nozzle supply passage and at least one closing hydraulic surface exposed to a fluid pressure of the first check control chamber.
3 more elements
A method of controlling a closing speed of a check needle during an injection event, said method comprising the steps of:
- moving a check needle from a first position to a second position by expelling fluid from a check control chamber to a low pressure drain, wherein at said first position, the check needle blocks an at least one nozzle outlet, and at said second position the check needle at least partially unblocks the at least one nozzle outlet;
- moving the check needle from the second position to the first position by preventing fluid communication between the check control chamber and the low pressure drain and filling the check control chamber with fluid;
- limiting a speed of the check needle as it moves from the second position to the first position by restricting the fluid filling the check control chamber with a check speed control device fixedly positioned within the check control chamber and having an upper bowl, a lower bowl and at least one orifice through the lower bowl.
An internal combustion engine comprising:
- an engine housing defining a plurality of engine cylinders, and including a plurality of pistons each being movable within a corresponding on of the engine cylinders;
- and
- a fuel system including a plurality of fuel injectors associated one with each of the plurality of engine cylinders, wherein at least one of the plurality of fuel injectors further includes:
- an injector body defining a high pressure inlet, a nozzle supply passage, a check control chamber, a check control line, a low pressure drain and at least one nozzle outlet;
- a check speed control device fixedly positioned within the check control chamber and having an upper bowl, a lower bowl and at least one orifice through the lower bowl;
- a control valve assembly having a valve member configured to selectively allow fluid communication from the upper bowl and check control line to the low pressure drain;
- and
- a check needle movable within the injector body between a first position at which the check needle blocks the at least one nozzle outlet and a second position at which the check needle at least partially opens the at least one nozzle outlet,
- the check needle including at least one opening hydraulic surface exposed to a fluid pressure of the nozzle supply passage and at least one closing hydraulic surface exposed to a fluid pressure of the first check control chamber.
6 more elements
Dependencies are inferred from the claim text.