High speed fuel injector

• US 5,460,329 A
• Filed: 06/06/1994
• Issued: 10/24/1995
• Est. Priority Date: 06/06/1994
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Oded E. Sturman
• Inventors: Sturman, Oded E.
• Primary Examiner(s): Shaver, Kevin P.
• Application Number:
  US08/254,271
• Time in Patent Office: 505 Days
• Field of Search: 239/88, 239/90, 239/92, 239/96, 251/30.01, 251/129.1
• US Class Current: 239/96
• CPC Class Codes: F02M 47/027 Electrically actuated valves draining the chamber to release the closing pressure
• CPC Class Codes: F02M 47/043 Fluid pressure acting on injection-valve in the period of non-injection to keep it closed
• CPC Class Codes: F02M 47/046 Fluid pressure acting on injection-valve in the period of injection to open it
• CPC Class Codes: F02M 57/025 hydraulic, e.g. with pressure amplification
• CPC Class Codes: F02M 59/105 hydraulic drive F02M59/32 takes precedence
• CPC Class Codes: F02M 59/466 Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means
• CPC Class Codes: F02M 63/0017 using electromagnetic operating means
• CPC Class Codes: F02M 63/004 Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
• CPC Class Codes: F02M 63/0049 Combined valve units, e.g. for controlling pumping chamber and injection valve

Abstract

A fuel injector which has a double solenoid three-way or four-way spool valve that controls the flow of a working fluid that is used to move an intensifier piston of the injector.

Claims

1. An upper fuel injector unit coupled to a lower fuel injector unit that has a nozzle coupled to a fuel port that receives a fuel, comprising:

a housing that has a supply working port and a return working port for receiving and releasing a working fluid;

an intensifier that moves between a return position and a power position, wherein said intensifier increases a fuel pressure to the nozzle when in the power position, said intensifier being adjacent to a first intensifier chamber and a second intensifier chamber;

a valve housing;

a spool that is located within said valve housing and moves between a first position and a second position wherein an end of said spool is in contact with said valve housing when said spool is in said first or second position, said spool being operatively connected to said working fluid ports and said intensifier chambers so that said first intensifier chamber is in fluid communication with said supply working port and said second intensifier chamber is in fluid communication with said return working port when said spool is in said first position, wherein said first intensifier chamber is pressurized and said intensifier moves to the return position, and said first intensifier chamber is in fluid communication with said return working port and said second intensifier chamber is in fluid communication with said supply working port when said spool is in said second position, wherein said second intensifier chamber is pressurized and said intensifier moves to the power position;

a first solenoid that can be energized to move said spool from said second position to said first position; and

,

a second solenoid that can be energized to move said spool from said first position to said second position, wherein said valve housing and said spool are constructed from a material with enough residual magnetism to maintain said spool position when said solenoids are de-energized and allows said spool end to be separated from said valve housing when said solenoid is energized.

2. The upper fuel unit injector as recited in claim 1, wherein the working fluid is also the fuel.

3. The upper fuel unit injector as recited in claim 1, wherein said housing has a supply working passage between said supply working port and said spool, a return working passage between said return working port and said spool, a first intensifier passage between said first intensifier chamber and said spool valve and a second intensifier passage between said second intensifier chamber and said spool, said spool having a first groove that provides fluid communication between said supply working passage and said first intensifier passage when said spool is in said first position and fluid communication between said supply working passage and said second intensifier passage when said spool is in said second position, said spool also having a pair of passages and an internal chamber that provide fluid communication between said second intensifier passage and said return working passage when said spool is in said first position, and fluid communication between said first intensifier passage and said return working passage when said spool is in said second position.

4. The upper fuel injector unit as recited in claim 3, wherein said spool moves within a valve chamber of spaced valve housing, said spool having a pair of openings that provide fluid communication between said inner chamber and said valve chamber.

5. The upper fuel injector unit as recited in claim 1, wherein said valve housing has a pair of bearing surfaces, said spool being cylindrical in shape with a pair opposite ends that engage said bearing surface and an outer longitudinal wall between said ends which contain the groove and the passages.

6. The upper fuel injector unit as recited in claim 5, wherein said valve housing and said spool are constructed from a steel.

7. A fuel injector, comprising:

a housing that has a fuel port for receiving a fuel, a supply working port and a return working port for receiving and releasing a working fluid, said housing further having a supply working passage in fluid communication with said supply working port, a return working passage in fluid communication with said return working port, a first intensifier passage in fluid communication with a first intensifier chamber and a second intensifier passage in fluid communication with a second intensifier chamber;

a nozzle that discharges the fuel from said housing;

an intensifier that moves between a return position and a power position, wherein said intensifier increases a fuel pressure to the nozzle when in the power position, said intensifier being adjacent to said first intensifier chamber and said second intensifier chamber;

a valve housing;

a spool that is located within said valve housing and moves between a first position and a second position wherein an end of said spool is in contact with said valve housing when said spool is in said first or second position, said spool having a first groove that provides fluid communication between said supply working passage and said first intensifier passage when said spool valve is in said first position and fluid communication between said supply working passage and said second intensifier passage when said spool is in said second position, said spool also having a pair of passages and an internal chamber that provide fluid communication between said second intensifier passage and said return working passage when said spool is in said first position, and fluid communication between said first intensifier passage and said return working passage when said spool is in said second position, wherein said first intensifier chamber is pressurized and said intensifier moves to the return position when said spool is in the first position and said second intensifier chamber is pressurized and said intensifier moves to the power position when said spool is in the second position;

a first solenoid operatively connected to said spool to move said spool from said second position to said first position; and

,

a second solenoid operatively connected to said spool to move said spool from said first position to said second position wherein said valve housing and said spool are constructed from a material with enough residual magnetism to maintain said spool position when said solenoids are de-energized and allows said spool end to be separated from said valve housing when said solenoid is energized.

8. The fuel injector as recited in claim 7, wherein said spool moves within a valve chamber of said valve housing, said spool having a pair of openings that provide fluid communication between said inner chamber and said valve chamber.

9. The fuel injector as recited in claim 7, wherein said housing has a passage that provides fluid communication between said fuel port and a spring chamber which houses a spring that biases said nozzle.

10. The fuel injector as recited in claim 7, wherein said housing has a passage that provides fluid communication between said supply working passage and a nozzle return chamber.

11. The fuel injector as recited in claim 7, wherein the working fluid is also the fuel.

12. The fuel injector as recited in claim 7, wherein said valve housing has a pair of bearing surfaces, said spool being cylindrical in shape with a pair opposite ends that engage said bearing surface and an outer longitudinal wall between said ends which contain the groove and the passages.

13. The fuel injector as recited in claim 12, wherein said valve housing and said spool are constructed from a magnetic steel.

14. An upper fuel injector unit coupled to a lower fuel injector unit that has a nozzle coupled to a fuel port that receives a fuel, comprising:

a housing that has a supply working port and a return working port for receiving and releasing a working fluid;

an intensifier that moves between a return position and a power position, wherein said intensifier increases a fuel pressure to the nozzle when in the power position, said intensifier being adjacent to a spring chamber and an intensifier chamber, said spring chamber being in fluid communication with said return working port;

a spring within said spring chamber, said spring biases said intensifier to the return position;

a valve housing;

a spool that moves between a first position and a second position wherein an end of said spool is in contact with said valve housing when said spool is in said first or second position, said spool being operatively connected to said working fluid ports and said intensifier chambers so that said intensifier chamber is in fluid communication with said return working port when said spool is in said first position, wherein said spring moves said intensifier to the return position, and said intensifier chamber is in fluid communication with said supply working port when said spool is in said second position, wherein said second intensifier chamber is pressurized and said intensifier moves to the power position;

a first solenoid that can be energized to move said spool from said second position to said first position; and

,

a second solenoid that can be energized to move said spool from said first position to said second position, wherein said valve housing and said spool are constructed from a material with enough residual magnetism to maintain said spool position when said solenoids are de-energized and allows said spool end to be separated from said valve housing when said solenoid is energized.

15. The upper fuel injector unit as recited in claim 14, wherein the working fluid is also the fuel.

16. The upper fuel injector unit as recited in claim 14, wherein said housing has a supply working passage connected to said supply working port and said spool, a return working passage connected to said return working port and said spool, a first intensifier passage connected to said spring chamber and said return working port and a second intensifier passage connected to said second intensifier chamber and said spool, said spool having a groove that provides fluid communication between said supply working passage and said intensifier passage when said spool is in said first position and fluid communication between said intensifier passage and said return working passage when said spool is in said second position.

17. The upper fuel injector unit as recited in claim 16, wherein said spool moves within a valve chamber of said valve housing, said spool having a pair of openings that provide fluid communication between said inner chamber and said valve chamber.

18. The upper fuel injector unit as recited in claim 16, wherein said valve housing has a pair of bearing surfaces, said spool being cylindrical in shape with a pair opposite ends that engage said bearing surface and an outer longitudinal wall between said ends which contain the groove and the passages.

19. The upper fuel injector unit as recited in claim 18, wherein said valve housing and said spool are constructed from a magnetic steel.

20. A fuel injector, comprising:

a housing that has a fuel port for receiving a fuel, a supply working port and a return working port for receiving and releasing a working fluid, said housing further having a supply working passage in fluid communication with said supply working port, a return working passage in fluid communication with said return working port, a first intensifier passage in fluid communication with said first intensifier chamber and a second intensifier passage in fluid communication with said second intensifier chamber;

a nozzle that discharges the fuel from said housing;

an intensifier that moves between a return position and a power position, wherein said intensifier increases a fuel pressure to the nozzle when in the power position, said intensifier being adjacent to a spring chamber and an intensifier chamber, said spring chamber being in fluid communication with said return working port;

a spring within said spring chamber, said spring biases said intensifier to the return position;

a valve housing;

a spool that is located within said valve housing and moves between a first position and a second position wherein an end of said spool is in contact with said housing when said spool is in said first or second position, said spool having a groove that provides fluid communication between said return working passage and said intensifier passage when said spool is in said first position, wherein said spring moves said intensifier to the return position, and said intensifier chamber is in fluid communication with said supply working port when said spool is in said second position, wherein said intensifier chamber is pressurized and said intensifier moves to the power position;

a first solenoid operatively connected to to move;

a first solenoid that can be energized to move said spool from said second position to said first position; and

,

a second solenoid that can be energized to move said spool from said first position to said second position, wherein said valve housing and said spool are constructed from a material with enough residual magnetism to maintain said spool position when said solenoids are de-energized and allows said spool end to be separated from said valve housing when said solenoid is energized.

21. The fuel injector as recited in claim 20, wherein said spool moves within a valve chamber of said valve housing, said spool having a pair of openings that provide fluid communication between said inner chamber and said valve chamber.

22. The fuel injector as recited in claim 20, wherein said housing has a passage that provides fluid communication between said fuel port and a spring chamber which houses a spring that biases said nozzle.

23. The fuel injector as recited in claim 20, wherein said housing has a passage that provides fluid communication between said supply working passage and a nozzle return chamber.

24. The fuel injector as recited in claim 20, wherein the working fluid is also the fuel.

25. The fuel injector as recited in claim 20, wherein said valve housing has a pair of bearing surfaces, said spool being cylindrical in shape with a pair opposite ends that engage said bearing surface and an outer longitudinal wall between said ends which contain the groove and the passages.

26. The fuel injector as recited in claim 25, wherein said valve housing and said spool are constructed from a magnetic steel.