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US 6,647,964 B1Granted
End of injection pressure reduction
AssigneeCaterpillar Inc.
InventorScott R. Schuricht
Life of this patent
Estimating the term…
Abstract
End of injection rate shaping can be attained by controlling the flow rate into a check control cavity. Specifically, a flow control valve allows the check control cavity to vent at a first flow rate and to pressurize at a second slower flow rate. By pressurizing at a slower rate, end of injection does not occur as quickly, allowing injection pressure to decrease before injection is terminated.
Claims13
A fuel injector comprising:
- a nozzle tip with a high pressure fuel cavity and an orifice connecting said high pressure fuel cavity to an outside of said nozzle tip;
- a check valve at least partially slideably disposed in said high pressure fuel cavity and moveable between a first position in which said orifice is in fluid communication with said high pressure fuel cavity and a second position in which said check blocks fluid communication of said orifice with said high pressure fuel cavity;
- a check control cavity;
- said check valve having an opening hydraulic surface in said high pressure fuel cavity and a closing hydraulic surface in said check control cavity;
- a first valve arrangement to selectively connect said check control cavity to either of a high pressure source and a low pressure drain;
- a flow control valve in fluid communication with said check control cavity, said flow control valve having a first flow rate in a first direction and a second flow rate in a second direction;
- wherein said first direction includes flow travel from said first valve arrangement to said check control cavity and said second direction includes flow travel from said check control cavity to said first valve arrangement;
- and
- wherein said first flow rate is less than said second flow rate.
6 more elements
A method of operating a check with a check control cavity comprising:
- moving a flow control valve to a first position including moving a flow ball check to an open position, for venting said check control cavity at a first flow rate to allow injection;
- and
- moving said flow control valve to a second position for pressurizing said check control cavity at a second flow rate to stop said injection, said second flow rate being less than said first flow rate.
A method of operating a check with a check control cavity comprising:
- venting said check control cavity at a first flow rate to allow injection;
- moving a rate shaping orifice plate to a first position, allowing flow to only travel through said rate shaping orifice;
- and
- pressurizing said check control cavity at a second flow rate to stop said injection, said second flow rate being less than said first flow rate.
1 more element
A fuel injector comprising:
- a nozzle tip with a high pressure fuel cavity and an orifice connecting said high pressure fuel cavity to an outside of said nozzle tip;
- a check valve at least partially slideably disposed in said high pressure fuel cavity and moveable between a first position in which said orifice is in fluid communication with said high pressure fuel cavity and a second position in which said check blocks fluid communication of said orifice with said high pressure fuel cavity;
- a check control cavity;
- said check valve having an opening hydraulic surface in said high pressure fuel cavity and a closing hydraulic surface in said check control cavity;
- a valve arrangement to selectively connect said check control cavity to either of a high pressure source and a low pressure drain;
- and
- means for controlling a flow rate between said valve arrangement and said check control cavity, said means having a first flow rate from said valve arrangement to said check control cavity and a second flow rate, greater than said first flow rate, from said check control cavity to said valve arrangement.
4 more elements
Dependencies are inferred from the claim text.