Fuel injector with hydraulically controlled check valve

• US 20020017573A1
• Filed: 10/05/2001
• Published: 02/14/2002
• Est. Priority Date: 06/06/1994
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Sturman, Oded E.
• Application Number:
  US09/972,114
• Publication Number:
  US 20020017573A1
• Time in Patent Office: Days
• 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 including an injector housing, a nozzle, a needle valve, and a nozzle return chamber. The nozzle discharges a fuel from the fuel injector. The needle valve has a first end adjacent to the nozzle to control the discharge of the fuel through the nozzle. The nozzle return chamber is adjacent a second end of the needle valve and receives a working fluid to bias the needle valve into the closed position.

Claims

1. A fuel injector, comprising:

an injector housing;

an intensifier piston located within the injector housing, the intensifier piston having a stroking cycle to increase a pressure of a fuel;

a nozzle coupled to the injector housing, the nozzle adapted to provide a discharge of the fuel through the nozzle during the stroking cycle of the intensifier piston;

a needle valve located within the injector housing, the needle valve having a first end adjacent to the nozzle and an opposing second end, the first end of the needle valve adapted to control the discharge of the fuel through the nozzle, the needle valve having an open position that allows the discharge of the fuel through the nozzle and a closed position that closes the nozzle; and

a nozzle return chamber within the injector housing adjacent the second end of the needle valve, the nozzle return chamber adapted to receive a working fluid to bias the needle valve into the closed position by a pressure of the working fluid.

2. The fuel injector of claim 1, wherein the intensifier piston is adapted to be motivated by the pressure of the working fluid to move through the stroking cycle.

3. The fuel injector of claim 2, further comprising a head member located within the injector housing and coupled to the intensifier piston, the head member adapted to be exposed to the pressure of the working fluid and generate a force that pushes the intensifier piston through the stroking cycle.

4. The fuel injector of claim 1, wherein the working fluid is a hydraulic fluid that circulates in a closed system separate from the fuel.

5. The fuel injector of claim 1, wherein the working fluid is the fuel.

6. A fuel injector, comprising:

an injector housing;

an intensifier means for increasing a pressure of a fuel during a stroking cycle;

a nozzle coupled to the injector housing, the nozzle adapted to provide a discharge of the fuel through the nozzle during the stroking cycle of the intensifier means;

a valve means for controlling the discharge of the fuel through the nozzle, the valve means having an open position that allows the discharge of the fuel through the nozzle and a closed position that closes the nozzle; and

a valve return means for receiving a working fluid to bias the valve means into the closed position by a pressure of the working fluid.

7. The fuel injector of claim 6, wherein the intensifier means is motivated by the working fluid to move through the stroking cycle.

8. The fuel injector of claim 6, wherein the working fluid is a hydraulic fluid that circulates in a closed system separate from the fuel.

9. The fuel injector of claim 6, wherein the working fluid is the fuel.

10. A method of controlling a discharge of a fuel from a fuel injector, comprising:

moving an intensifier piston through a stroking cycle to increase a pressure of the fuel;

discharging the fuel from the fuel injector through a nozzle during the stroking cycle of the intensifier piston; and

providing a working fluid to a nozzle return chamber for biasing a needle valve into a closed position by a pressure of the working fluid, the needle valve being adapted to control the discharging of the fuel through the nozzle, the needle valve having an open position that allows the discharging of the fuel through the nozzle and the closed position that closes the nozzle.

11. The method of claim 10, wherein a head member is coupled to the intensifier piston and moving the intensifier piston through the stroking cycle further comprises exposing the head member to the pressure of the working fluid to generate a force that pushes the intensifier piston through the stroking cycle.

12. The method of claim 10, wherein the working fluid is a hydraulic fluid that circulates in a closed system separate from the fuel.

13. The method of claim 10, wherein the working fluid is the fuel.