Fuel system having isolation valves between fuel injectors and common drain conduit

Patent metadata

Field	Value
Publication number	US-11220980-B2
Application number	US-201916414522-A
Country	US
Kind code	B2
Filing date	May 16, 2019
Priority date	May 16, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A fuel system includes a plurality of fuel injectors connected to a common drain conduit, and a plurality of isolation valve assemblies each positioned fluidly between the common drain conduit and one of the plurality of fuel injectors. Each isolation valve assembly includes a valve member movable between a closed position to block an injection control valve assembly in the fuel injector from the common drain conduit, and an open position, and a biaser biasing the isolation valve member toward the closed position such that fuel injectors are isolated from fluid pressure pulses produced by nozzle check actuation to limit cross-talk among the fuel injectors.

First claim

What is claimed is:

1. A fuel system comprising:
a plurality of fuel injectors, each of the plurality of fuel injectors including an injection control valve assembly and a direct operated nozzle check, and having a high pressure nozzle supply passage, a first low pressure outlet, a second low pressure outlet, and a check control chamber formed therein;
a common drain conduit fluidly connected to each of the plurality of fuel injectors to receive drained actuating fluid for each of the direct operated nozzle checks;
a plurality of isolation valve assemblies and a plurality of drain lines, each of the plurality of isolation valve assemblies being positioned fluidly between the injection control valve assembly of one of the plurality of fuel injectors and one of the plurality of drain lines;
the plurality of drain lines each forming one drain line connection to the common drain conduit for draining actuating fluid from the one of the plurality of isolation valve assemblies, and a total number of drain line connections in the fuel system for draining actuating fluid from the plurality of isolation valve assemblies to the common drain conduit is equal to a total number of the plurality of fuel injectors in the fuel system;
each of the plurality of isolation valve assemblies including a first isolation valve member movable between a closed position blocking the injection control valve assembly in the respective one of the plurality of fuel injectors from the corresponding first low pressure outlet, and an open position, and a first spring biaser biasing the isolation valve member toward the closed position;
each of the plurality of isolation valve assemblies includes a second isolation valve member movable between a closed position blocking the injection control valve assembly in the respective one of the plurality of fuel injectors from the corresponding second low pressure outlet, and an open position, and a second spring biaser biasing the second isolation valve member toward the closed position; and
each of the plurality of isolation valve assemblies is resident in the respective one of the plurality of fuel injectors.

2. The fuel system of claim 1 wherein each of the plurality of isolation valve assemblies includes a valve body having formed therein a first outlet fluidly connected to the common drain conduit and a second outlet fluidly connected to the common drain conduit.

3. The fuel system of claim 2 wherein in each respective one of the plurality of fuel injectors:
a valve seat is positioned fluidly between the check control chamber and each of the first outlet and the second outlet;
the injection control valve assembly includes a control valve member movable between a closed control valve position blocking the valve seat, and an open control valve position; and
the first isolation valve member is positioned fluidly between the valve seat and the first outlet, and the second isolation valve member is positioned fluidly between the valve seat and the second outlet.

4. The fuel system of claim 1 wherein:
each of the plurality of isolation valve assemblies further includes a first snap ring and a second snap ring within the corresponding one of the plurality of fuel injectors; and
the first spring biaser includes a first biasing spring held in compression between the first snap ring and the first isolation valve member and the second spring biaser includes a second biasing spring held in compression between the second snap ring and the second isolation valve member.

5. The fuel system of claim 1 wherein each of the first isolation valve member and the second isolation valve member includes a stem, a head attached to the stem, and an outlet passage extending through the stem and in fluid communication with the common drain conduit at the open position of the respective isolation valve member.

6. The fuel system of claim 5 wherein each of the plurality of fuel injectors includes a high pressure inlet, and further comprising a common rail in fluid communication with the high pressure inlet of each of the plurality of fuel injectors.

7. A fuel injector comprising:
an injector body having a high pressure nozzle supply passage, a check control chamber, and a valve body having a first low pressure outlet and a second low pressure outlet formed therein;
a direct operated nozzle check;
an injection control valve assembly; and
an isolation valve assembly including a first isolation valve member movable between a closed position fluidly isolating the injection control valve assembly from the first low pressure outlet, and an open position, a first spring biaser biasing the first isolation valve member toward the closed position, and a first snap ring supported in the valve body, and the first spring biaser is trapped between the first snap ring and the first isolation valve member;
the isolation valve assembly further including a second isolation valve member movable between a closed position fluidly isolating the injection control valve assembly from the second low pressure outlet, and an open position, and a second spring biaser biasing the second isolation valve member toward the closed position, and a second snap ring supported in the valve body, and the second spring biaser is trapped between the second snap ring and the second isolation valve member; and
each of the first isolation valve member and the second isolation valve member defining a longitudinal axis and including a valve head having an axial end surface in contact with the respective spring biaser, an underhead surface, and a valve stem extending from the underhead surface, and the underhead surface is in contact with the injector body at the respective closed position.

8. The fuel injector of claim 7 wherein the injector body has a valve seat formed therein, and wherein each of the first isolation valve member and the second isolation valve member is positioned fluidly between the valve seat and the respective one of the first low pressure outlet and the second low pressure outlet.

9. The fuel injector of claim 8 wherein:
the valve body has a first bore formed therein extending between the valve seat and the first low pressure outlet, and a second bore larger than the first bore connecting with the first bore and receiving the first isolation valve member therein; and
the valve body further has a third bore formed therein extending between the valve seat and the second low pressure outlet, and a fourth bore larger than the third bore and receiving the second isolation valve member therein.

10. The fuel injector of claim 9 wherein the stem of the first isolation valve member is within the second bore at each of the respective closed position and open position, and the stem of the second isolation valve member is within the fourth bore at each of the respective closed position and open position.

11. The fuel injector of claim 10 wherein the first isolation valve member has an outlet passage formed in the stem, and the outlet passage is fluidly connected to the low pressure outlet at the open position of the first isolation valve member.

12. The fuel injector of claim 10 wherein the valve head of the first isolation valve member includes a downstream side oriented toward the first low pressure outlet, and an upstream side, and wherein the first spring biaser includes a biasing spring in contact with the downstream side of the valve head of the first isolation valve member.

13. The fuel injector of claim 7 wherein the injector body has a high pressure inlet and a plurality of nozzle outlets formed therein, and wherein the direct operated nozzle check is movable between a closed c

Assignees

• Caterpillar Inc

Inventors

• Nair Siddharth
• Bannur Nagaraja Manjunath

Classifications

• F02M21/0251 Primary

  Details of actuators therefor · CPC title

• F02M47/027 Primary

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

• F02M55/007

  Venting means · CPC title

• F02M63/0054

  Check valves (F02M59/462, F02M59/464 take precedence) · CPC title

• F02M63/0215

  by draining or closing fuel conduits · CPC title