System and method for control of fuel injector spray

Patent metadata

Field	Value
Publication number	US-9562505-B2
Application number	US-201313915305-A
Country	US
Kind code	B2
Filing date	Jun 11, 2013
Priority date	Jun 11, 2013
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The disclosure provides an improved fuel injector and method of operating the fuel injector to provide at least two different types of fuel spray to a combustion chamber of an internal combustion engine. The two types of spray are formed by providing a first fuel pressure to the fuel injector during a first portion of an injection event at a first pressure and providing a second fuel pressure to the fuel injection during a second portion of the injection event, and maintaining a substantially constant fuel flow rate throughout the injection event.

First claim

We claim:

1. A fuel system for injecting fuel into a combustion chamber of an internal combustion engine, the fuel system comprising:
a variable pressure fuel supply configured to selectively supply fuel at different pressure levels;
a fuel injector including,
an injector body containing an injector cavity and a plurality of injector orifices communicating with a first end of the injector cavity to discharge fuel into the combustion chamber, the plurality of injector orifices including a first set of injector orifices and a second set of injector orifices, the injector body including a fuel transfer circuit for transferring fuel to the plurality of injector orifices;
a first needle valve element positioned in the injector cavity for controlling fuel flow through the first set of injector orifices and a first valve seat formed on the injector body, the first needle valve element movable from a closed position against the first valve seat blocking flow through the first set of injector orifices to an open position permitting flow through the first set of injector orifices;
a second needle valve element positioned in the injector cavity for controlling fuel flow through the second set of injector orifices and a second valve seat formed on the injector body, the second needle valve element movable from a closed position against the second valve seat blocking flow through the second set of injector orifices to an open position permitting flow through the second set of injector orifices; and
an actuator movable to permit movement of the first and the second needle valve elements between the open and closed positions to define an injection event; and

a controller connected to the actuator and to the variable pressure fuel supply, the controller configured to generate a control signal to cause the variable pressure fuel supply to supply fuel to the injector cavity at a first pressure level during an initial portion of the injection event and at a second pressure level, higher than the first pressure level, during a subsequent portion of the injection event occurring after the initial portion,
wherein the first and the second set of injector orifices are sized to maintain a flow rate of fuel into the combustion chamber at a substantially constant rate during the initial portion of the injection event and the subsequent portion of the injection event.

2. The fuel system of claim 1 , wherein fuel is supplied to the injector cavity at the second pressure level when the second needle valve element is in the open position and the first needle valve element is in the closed position.

3. The fuel system of claim 2 , wherein fuel is supplied to the injector cavity at the second pressure level for substantially the entire time the second needle valve element is in the open position while the first needle valve element is in the closed position.

4. The fuel system of claim 1 , wherein the first needle valve element is telescopingly received within a cavity formed in the second needle valve element to form a sliding fit with an inner surface of the second needle valve element.

5. The fuel system of claim 1 , wherein the variable pressure fuel supply includes a fuel pressure amplifier fluidly connected to the injector cavity.

6. The fuel system of claim 5 , wherein the fuel pressure amplifier is mounted on the injector body.

7. The fuel system of claim 1 , wherein the first and the second set of injector orifices are sized to maintain a flow rate of fuel into the combustion chamber at a substantially constant rate throughout the initial portion of the injection event and the subsequent portion of the injection event.

8. The fuel system of claim 1 , wherein the variable pressure fuel supply includes a first fuel accumulator and a second fuel accumulator selectively connected by a valve to the fuel injector.

9. A fuel system for injecting fuel into a combustion chamber of an internal combustion engine, the fuel system comprising:
a variable pressure fuel supply configured to selectively supply fuel at a first pressure level and a second pressure level higher than the first pressure level during an injection event;
a fuel injector including,
an injector body containing an injector cavity and a plurality of injector orifices communicating with a first end of the injector cavity to discharge fuel into the combustion chamber, the plurality of injector orifices including a first set of injector orifices and a second set of injector orifices, the injector body including a fuel transfer circuit for transferring fuel to the plurality of injector orifices;
a first needle valve element positioned in the injector cavity for controlling fuel flow through the first set of injector orifices and a first valve seat formed on the injector body, the first needle valve element movable from a closed position against the first valve seat blocking flow through the first set of injector orifices to an open position permitting flow through the first set of injector orifices; and
a second needle valve element positioned in the injector cavity for controlling fuel flow through the second set of injector orifices and a second valve seat formed on the injector body, the second needle valve element movable from a closed position against the second valve seat blocking flow through the second set of injector orifices to an open position permitting flow through the second set of injector orifices; and

the first and the second set of injector orifices sized to provide a first fuel flow rate in response to the variable pressure fuel supply supplying fuel at the first pressure level, and the second set of injector orifices sized to provide a second fuel flow rate substantially equal to the first fuel flow rate in response to the variable pressure fuel supply supplying fuel at the second pressure level, when the second needle valve element is in the open position and the first needle valve element is in the closed position.

10. The fuel system of claim 9 , wherein the first needle valve element is telescopingly received within a cavity formed in the second needle valve element to form a sliding fit with an inner surface of the second needle valve element.

11. The fuel system of claim 9 , wherein the variable pressure fuel supply includes a fuel pressure amplifier fluidly connected to the injector cavity.

12. The fuel system of claim 11 , wherein the fuel pressure amplifier is mounted on the injector body.

13. The fuel system of claim 9 , wherein the variable pressure fuel supply includes a first fuel accumulator and a second fuel accumulator selectively connected by a valve to the fuel injector.

14. A method of providing fuel to a combustion chamber from a fuel injector of an internal combustion engine, the method comprising:
providing fuel to the fuel injector at a first fuel pressure level and into the combustion chamber at a fuel flow rate through a first set of injector orifices and a second set of injector orifices, during a first portion of an injection event; and
providing fuel to the fuel injector at a second fuel pressure level higher than the first fuel pressure level and into the combustion chamber through the second set of injector orifices to cause fuel flow into the combustion chamber at substantially the same fuel flow rate, during a second portion of the injection event.

15. The method of claim 14 , the fuel injector comprising a plurality of valve elements, the method further comprising controlling fuel flow through the first set of injector orifices and the second set of injector orifices formed in the fuel injector with the plurality of valve elements

Assignees

• Cummins Inc

Inventors

• Hokkanen Vesa
• Buchanan David L
• Peters Lester L
• Garg Rajesh K

Classifications

• F02M2200/46

  Valves, e.g. injectors, with concentric valve bodies · CPC title

• F02M2200/703

  hydraulic · CPC title

• F02M63/029 Primary

  per cylinder bank, e.g. storing different fuels or fuels at different pressure levels per cylinder bank · CPC title

• F02M51/0603

  using piezoelectric or magnetostrictive operating means · CPC title

• F02M45/086

  Having more than one injection-valve controlling discharge orifices · CPC title