Method for cooling a direct injection pump

Patent metadata

Field	Value
Publication number	US-10077749-B2
Application number	US-201715583426-A
Country	US
Kind code	B2
Filing date	May 1, 2017
Priority date	Feb 20, 2015
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

Methods and systems are provided for cooling a high pressure fuel pump. One method includes, when a spill valve is in a pass-through state, circulating fuel from a compression chamber of the high pressure fuel pump to a step room of the high pressure fuel pump. The fuel circulation through the step room may provide for a reduction in fuel temperature in the step room, and thus, the high pressure fuel pump.

First claim

The invention claimed is:

1. A method, comprising:
during a compression stroke of a direct injection pump when a spill valve is in a pass-through state,
circulating a portion of fuel from a compression chamber of the direct injection pump to a step room of the direct injection pump through the spill valve, the accumulator positioned upstream of the spill valve and downstream of a lift pump with a first check valve positioned between the accumulator and the spill valve; and
returning the portion of fuel exiting the step room through a fuel supply line to the accumulator upstream of the first check valve.

2. The method of claim 1 , wherein the drawing of the portion of fuel into the step room from upstream of the spill valve and downstream of an accumulator includes drawing the portion of fuel from upstream of the spill valve and downstream of the first check valve.

3. The method of claim 2 , wherein the portion of fuel drawn into the step room from upstream of the spill valve and downstream of the first check valve flows through a second check valve, the second check valve arranged upstream of the step room.

4. The method of claim 3 , wherein the portion of fuel includes reflux fuel from the compression chamber.

5. The method of claim 1 , wherein the portion of fuel is substantially stored in the accumulator during a period of the compression stroke, and wherein the portion of fuel is released during a duration of a suction stroke in the direct injection pump.

6. The method of claim 1 , wherein the direct injection pump includes a pump piston coupled to a piston stem, the piston stem having an external diameter that is substantially the same as an external diameter of the pump piston.

7. The method of claim 1 , wherein the direct injection pump includes a pump piston coupled to a piston stem, the piston stem having an external diameter that is substantially half of an external diameter of the pump piston.

8. A method, comprising:
when a solenoid activated check valve is in a pass-through state,
flowing reflux fuel from a compression chamber of a direct injection fuel pump via the solenoid activated check valve and through a step room into an accumulator, the reflux fuel flowing into the accumulator only after flowing through the step room, wherein the accumulator is arranged upstream of each of a first check valve and the solenoid activated check valve, the direct injection fuel pump positioned downstream of a lift pump.

9. The method of claim 8 , wherein the reflux fuel flows from the compression chamber via the solenoid activated check valve into the step room via a second check valve in a passage, an inlet of the passage fluidically coupled between the first check valve and the solenoid activated check valve.

10. The method of claim 8 , wherein the flowing of the reflux fuel occurs substantially during a compression stroke in the direct injection fuel pump.

11. A system, comprising:
a lift pump;
a direct injection fuel pump including a piston coupled to a piston stem, a compression chamber, a step room, and a cam for driving the piston;
a high pressure fuel rail fluidically coupled to an outlet of the direct injection fuel pump;
a solenoid activated check valve positioned at an inlet of the direct injection fuel pump;
a fuel supply line fluidically coupling the lift pump and the solenoid activated check valve;
an accumulator positioned upstream of the solenoid activated check valve, the accumulator fluidically communicating with the fuel supply line;
a first check valve coupled to the fuel supply line between the accumulator and the solenoid activated check valve;
a first fuel conduit including a second check valve;
a first end of the first fuel conduit fluidically coupled to the fuel supply line between the first check valve and the solenoid activated check valve;
a second end of the first fuel conduit fluidically coupled to an inlet of the step room;
a second fuel conduit;
a first end of the second fuel conduit fluidically coupled to an outlet of the step room; and
a second end of the second fuel conduit fluidically coupled to the fuel supply line at the accumulator upstream of the first check valve and downstream of a third check valve.

12. The system of claim 11 , further comprising a controller having executable instructions stored in a non-transitory memory for de-energizing the solenoid activated check valve to function in a pass-through state.

13. The system of claim 12 , wherein during a portion of a compression stroke in the direct injection fuel pump, reflux fuel from the compression chamber flows to the step room via the solenoid activated check valve in the pass-through state, into the first end of the first fuel conduit, through the second check valve, and via the second end of the first fuel conduit into the inlet of the step room.

14. The system of claim 13 , wherein the reflux fuel further streams from the outlet of the step room into the first end of the second fuel conduit towards the accumulator and the fuel supply line via the second end of the second fuel conduit.

15. The system of claim 14 , wherein the solenoid activated check valve is de-energized for an entire pump stroke during a default pressure mode of operation of the direct injection fuel pump.

16. The system of claim 14 , wherein the solenoid activated check valve is de-energized for a portion of a pump stroke during a variable pressure mode of operation of the direct injection fuel pump.

Assignees

• Ford Global Tech Llc

Inventors

• Ulrey Joseph Norman
• Pursifull Ross Dykstra

Classifications

• F02M59/462

  Delivery valves · CPC title

• F02D41/2406

  using essentially read only memories · CPC title

• F02M59/466 Primary

  Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means · CPC title

• F02M59/027

  Unit-pumps, i.e. single piston and cylinder pump-units, e.g. for cooperating with a camshaft · CPC title

• F02D41/3845 Primary

  by controlling the flow into the common rail, e.g. the amount of fuel pumped · CPC title