Pressure device to reduce ticking noise during engine idling

Patent metadata

Field	Value
Publication number	US-9683512-B2
Application number	US-201414286648-A
Country	US
Kind code	B2
Filing date	May 23, 2014
Priority date	May 23, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Systems and methods are provided for a high-pressure fuel pump to mitigate audible ticking noise associated with opening and closing of a digital inlet valve of the high-pressure pump. To reduce the ticking noise associated with the high-pressure pump when the engine is idling, a solution is needed that is simple and does not involve retrofitting the fuel system with noise, vibration, and harshness countermeasures to mask the noise. Pressure devices and associated operation methods are provided that involve adding a combination of several check valves, an accumulator, and a flow control valve with weep channels to allow the digital inlet valve to be deactivated during engine idling as defined by a threshold engine speed.

First claim

The invention claimed is:

1. A method, comprising:
determining, via a controller, an engine idling condition in response to an engine running below a threshold speed and a non-engine idling condition in response to the engine running above the threshold speed;
in response to the engine idling condition, regulating high-pressure fuel pump pressure via a pressure device including first and second check valves with opposite orientations without activating a digital inlet valve coupled to an inlet of a high-pressure fuel pump, the regulating including delivering fuel to a fuel rail while maintaining the digital inlet valve deactivated, where the digital inlet valve is maintained deactivated until the end of the engine idling condition; and
in response to the non engine idling condition, adjusting activation of the digital inlet valve to regulate fuel pressure.

2. The method of claim 1 , wherein a solenoid of the digital inlet valve is not energized during the engine idling condition.

3. The method of claim 1 , wherein regulating fuel pressure during the engine idling condition includes allowing fuel to backflow through the digital inlet valve into the pressure device, the second check valve substantially preventing fuel from flowing backward upstream of the pressure device while fuel pressure is lower than a threshold pressure, and delivering fuel to the fuel rail.

4. The method of claim 1 , wherein regulating fuel pressure during the non-engine idling condition includes trapping fuel in a compression chamber of the high-pressure fuel pump.

5. The method of claim 1 , wherein the pressure device is located inside the high-pressure fuel pump and the first check valve is an inlet check valve biased to allow fuel to enter a compression chamber of the high-pressure fuel pump, wherein the pressure device is downstream of the digital inlet valve, and wherein maintaining the digital inlet valve deactivated includes maintaining the digital inlet valve open.

6. The method of claim 1 , wherein the second check valve is a pressure relief valve biased to allow fuel to backflow from the high-pressure fuel pump towards a low-pressure fuel pump when fuel pressure in a compression chamber of the high-pressure fuel pump exceeds a pressure threshold.

7. The method of claim 1 , wherein the digital inlet valve is an electronically-controlled inlet valve switchable between an activated, closed position to substantially prevent backward fuel flow through the digital inlet valve and a deactivated, open position to allow fuel flow through the digital inlet valve.

8. A method for operating a high-pressure fuel pump, comprising:
determining, via a controller, an idling condition including operating the high-pressure fuel pump when an engine driving the high-pressure fuel pump is running below a threshold speed;
during an intake stroke of the high-pressure pump, deactivating a digital inlet valve to an open position, allowing fuel to flow into a compression chamber of the high-pressure fuel pump;
during a first delivery stroke of the pump when in the idling condition, delivering fuel to a fuel rail while maintaining the digital inlet valve in the open position, where fuel compressed by the pump compresses a flexible accumulator located in a pressure device upstream of the digital inlet valve, the pressure device including two check valves with opposite orientations, and where the digital inlet valve is maintained open until the idling condition ends; and
during a second delivery stroke of the pump when not in the idling condition, delivering fuel to the fuel rail by activating the digital inlet valve to a closed position to trap fuel inside the compression chamber of the pump, and not compressing the accumulator by fuel.

9. The method of claim 8 , wherein maintaining the digital inlet valve in the open position includes maintaining a solenoid valve deactivated.

10. The method of claim 8 , wherein the flexible accumulator includes a generally spherical diaphragm allowing pressurized fuel to compress the accumulator during the first delivery stroke of the pump, and wherein the accumulator is downstream of the check valves.

11. The method of claim 8 , wherein during the second delivery stroke, the digital inlet valve is activated to the closed position from the open position of the intake stroke, and wherein the accumulator is upstream of the check valves.

12. The method of claim 8 , wherein during the second delivery stroke, the digital inlet valve is activated to the closed position based on angular position of a driving cam providing linear motion to a plunger of the high-pressure fuel pump, and wherein the pressure device is downstream of the digital inlet valve.

13. A fuel system, comprising:
a high-pressure fuel pump with an outlet fluidly coupled to a fuel rail and an inlet fluidly coupled to a digitally-controlled inlet valve coupled to an electronic control system, the digital inlet valve receiving fuel from a low-pressure fuel pump;
a pressure device including one or more check valves with opposite orientations; and
a controller with machine-readable instructions stored in non-transitory memory for:
determining an idle condition in response to an engine speed below a threshold and determining a non-idle condition in response to the engine speed above the threshold;
delivering fuel to the fuel rail while maintaining the digital inlet valve deactivated during the idle condition; and
delivering fuel to the fuel rail by activating the digital inlet valve during the non-idle condition;

wherein the pressure device includes an accumulator downstream of the one or more check valves; and
wherein the digital inlet valve is maintained deactivated until the idle condition ends.

14. The system of claim 13 , wherein the pressure device is located upstream of the digital inlet valve and integrally affixes to a housing of the high-pressure fuel pump, forming a single contiguous housing that includes the high-pressure fuel pump and pressure device.

15. The system of claim 13 , wherein the pressure device is located upstream of the digital inlet valve and attached to the digital inlet valve via an inlet line, the pressure device including a device housing separate from a housing of the high-pressure fuel pump.

16. The system of claim 13 , wherein the pressure device is located inside a compression chamber of the high-pressure fuel pump, downstream of the digital inlet valve.

17. The system of claim 13 , the pressure device further comprising a device housing with a dividing wall located interior of the device housing, the dividing wall forming an inlet chamber and an outlet chamber of the pressure device.

18. The system of claim 17 , wherein two of the check valves are positioned in the dividing wall to allow fuel to travel upstream or downstream of the pressure device based on pressure of the fuel; and
wherein delivering fuel includes a plurality of pump strokes of the high-pressure fuel pump.

19. The system of claim 13 , wherein one of the check valves is a pressure relief valve to allow fuel compressed above a threshold pressure to escape from the high-pressure fuel pump and pressure device back into a passage coupled to the low-pressure fuel pump.

20. The system of claim 13 , wherein one of the check valves is a flow control valve biased to allow fuel to enter the digital inlet valve, the flow control valve including weep channels to allow fuel to flow upstream through the flow control valve.

Assignees

• Ford Global Tech Llc

Inventors

• Stickler Mark L
• Solferino Vince Paul
• Zeng Paul
• Pursifull Ross Dykstra
• Lawther Robin Ivo
• Brostrom Patrick
• Jensen Jacob
• Woodring Christopher
• Basmaji Joseph F
• Meinhart Mark
• Surnilla Gopichandra

Classifications

• F02D2200/101

  Engine speed · CPC title

• F02M63/005

  Pressure relief valves · CPC title

• F02D41/3845 Primary

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

• F02M59/368

  Pump inlet valves being closed when actuated · CPC title

• F02M2200/09

  Fuel-injection apparatus having means for reducing noise · CPC title