Fuel injector for dual fuel common rail system

Patent metadata

Field	Value
Publication number	US-9453483-B2
Application number	US-201113221187-A
Country	US
Kind code	B2
Filing date	Aug 30, 2011
Priority date	Aug 30, 2011
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A duel fuel system includes a plurality of fuel injectors that have a non-injection configuration, a liquid fuel injection configuration, a gaseous fuel injection configuration and a combined fuel injection configuration. Each of the fuel injectors is fluidly connected to a gaseous fuel common rail and a liquid fuel common rail. Each of the fuel injectors includes a three way gas control valve and a three way liquid control valve that move along a common centerline. A gas control chamber of each fuel injector is fluidly connected to the liquid fuel common rail by two passages in parallel when the gas control valve member is in a first position corresponding to the non-injection configuration. The liquid control chamber of each fuel injector is also fluidly connected to the liquid fuel common rail by two passages in parallel when the liquid control valve is in a first position, again corresponding to the non-injection configuration.

First claim

What is claimed is:

1. A fuel injector comprising:
an injector body defining a first nozzle outlet set, a first fuel inlet, a second nozzle outlet set, a second fuel inlet, and a drain outlet and having disposed therein a first nozzle chamber fluidly connected to the first fuel inlet, a second nozzle chamber fluidly connected to the second fuel inlet, a first control chamber fluidly connected to the first fuel inlet, and a second control chamber fluidly connected to the first fuel inlet;
a first needle control valve positioned in the injector body and including a first control valve member movable between a first position in contact with a conical seat to close a first fluid connection between the first control chamber and the drain outlet, and a second position out of contact with the conical seat to open the first fluid connection;
a second needle control valve positioned in the injector body and including a second control valve member movable between a first position in contact with a conical seat to close a second fluid connection between the second control chamber and the drain outlet, and a second position out of contact with the conical seat to open the second fluid connection;
a first solenoid actuator with a first armature operably coupled to the first needle control valve;
a second solenoid actuator with a second armature operably coupled to the second needle control valve; and
the first control valve member, the second control valve member, the first armature and the second armature move along a common centerline.

2. The fuel injector of claim 1 wherein the first control valve member is trapped to move between an upper conical seat and a lower conical seat;
the second control valve member is trapped to move between the conical seat and a flat valve seat; and
each of the first and second control chambers is fluidly connected to the first fuel inlet through two passages in parallel when the first and second control valve members are in their respective first positions.

3. The fuel injector of claim 1 wherein the first solenoid actuator and the second solenoid actuator have separate coils but share a shared stator.

4. The fuel injector of claim 1 wherein the first fuel inlet is surrounded by an inner conical seat and an outer conical seat;
the second fuel inlet opens between the inner conical seat and the outer conical seat; and
the first nozzle outlet set and the second nozzle outlet set are defined by a tip component of the injector body.

5. The fuel injector of claim 1 including a first needle valve member with an opening hydraulic surface positioned in the first nozzle chamber, a closing hydraulic surface positioned in the first control chamber, and being movable into and out of contact with a first nozzle seat to close and open, respectively, the first nozzle chamber to the first nozzle outlet set; and
a second needle valve member with an opening pneumatic surface positioned in the second nozzle chamber, a closing hydraulic surface positioned in the second control chamber, and being movable in and out of contact with a second nozzle seat to close and open, respectively, the second nozzle chamber to the second nozzle outlet set.

6. The fuel injector of claim 5 including a hydraulic lock seal that includes an annular volume surrounding a guide segment of the second needle valve member, and a seal passage fluidly connecting the annular volume to the first nozzle chamber.

7. The fuel injector of claim 6 wherein each of the first and second needle valve members move parallel to, but offset from, the common centerline.

8. The fuel injector of claim 7 wherein the first control valve member is trapped to move between an upper conical seat and a lower conical seat; and
the second control valve member is trapped to move between the conical seat and a flat valve seat;
the first solenoid actuator and the second solenoid actuator have separate coils but share a common stator;
the first fuel inlet is surrounded by a first common rail conical seat and a second common rail conical seat;
the second fuel inlet opens between the first common rail conical seat and the second common rail conical seat;
the first nozzle outlet set and the second nozzle outlet set are defined by a tip component of the injector body; and
each of the first and second control chambers is fluidly connected to the first fuel inlet through two passages in parallel when the first and second control valve members are in their respective first positions.

9. A dual fuel system comprising:
a plurality of fuel injectors that have a non-injection configuration, a liquid fuel injection configuration, a gaseous fuel injection configuration and a combined fuel injection configuration;
a gaseous fuel common rail fluidly connected to each of the fuel injectors;
a liquid fuel common rail fluidly connected to each of the fuel injectors; and
each of the fuel injectors includes a three way gas control valve with a gas control valve member and a three way liquid control valve with a liquid control valve member that each move along a common centerline;
a gas control chamber of each fuel injector being fluidly connected to the liquid fuel common rail by two passages in parallel when the gas control valve member is in a first position; and
a liquid control chamber of each fuel injector being fluidly connected to the liquid fuel common rail by two passages in parallel when the liquid control valve member is in a first position.

10. The dual fuel system of claim 9 wherein each of the fuel injectors includes a first electrical actuator operably coupled to the three way liquid control valve and a second electrical actuator operably coupled to the three way gas control valve;
the second electrical actuator includes an armature attached to move with a pusher that extends through a bore defined by the liquid control valve member.

11. The dual fuel system of claim 10 wherein the first electrical actuator and the second electrical actuator share a common stator.

12. The dual fuel system of claim 11 wherein each of the fuel injectors is fluidly connected to a quill by a pair of concentric tubes.

13. The dual fuel system of claim 12 including an electronic controller in control communication with a gas pressure control device, a liquid pressure control device and each of the fuel injectors, and including a dual fuel control algorithm configured to maintain a small pressure differential between the liquid fuel common rail and the gaseous fuel common rail, and a single fuel control algorithm configured to maintain a large pressure differential between the liquid fuel common rail and the gaseous fuel common rail.

14. The dual fuel system of claim 13 wherein each of the fuel injectors includes a hydraulic lock seal with an annular volume that surrounds a guide segment of a gas needle valve member, and a seal passage that fluidly connects the annular volume to the liquid fuel common rail.

15. A method of operating a dual fuel system comprising the steps of:
injecting gaseous and liquid fuels through a gaseous nozzle outlet set and liquid nozzle outlet set, respectively, of a fuel injector into an engine cylinder in an engine cycle;
compression igniting the liquid fuel;
wherein the step of injecting includes moving a first armature, a second armature, a liquid control valve member, and a gas control valve member along a common centerline; and
wherein the step of moving a liquid control valve member includes closing one of two passages fluidly connecting a liquid needle control chamber to a liquid common rail and opening a fluid connection from t

Assignees

• Kim Hoisan
• Caterpillar Inc

Inventors

• Kim Hoisan

Classifications

• F02M2200/44

  Valves, e.g. injectors, with valve bodies arranged side-by-side · CPC title

• Y02T10/36

  Cross-Sectional Technologies · mapped topic

• F02M47/027

  Electrically actuated valves draining the chamber to release the closing pressure · CPC title

• F02M63/0064

  Two or more actuators acting on two or more valve bodies · CPC title

• F02D19/0647

  the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME] · CPC title