Engine cooling system motor driven vacuum pump

Patent metadata

Field	Value
Publication number	US-9309840-B2
Application number	US-201213633804-A
Country	US
Kind code	B2
Filing date	Oct 2, 2012
Priority date	Oct 2, 2012
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

Embodiments for monitoring fuel system degradation are provided. In one example, a method comprises driving a cooling fan with an electric motor in a vehicle, and during selected conditions, also driving a vacuum pump with the electric motor through a clutch. In this way, fuel system degradation may be indicated without use of a separate motor to drive a pressure building device.

First claim

The invention claimed is:

1. A method, comprising:
driving a cooling fan with an electric motor in a vehicle; and
during selected conditions, also driving a vacuum pump with the electric motor through a clutch, the selected conditions comprising performing a fuel system leak detection test on a fuel system of the vehicle.

2. The method of claim 1 , wherein the selected conditions further comprise following a key-off event where the cooling fan is still driven by the electric motor.

3. The method of claim 1 , wherein the selected conditions further comprise a temperature of an engine of the vehicle being below a threshold.

4. The method of claim 1 , wherein performing the fuel system leak detection test comprises applying vacuum to the fuel system with the vacuum pump and indicating a fuel system leak in response to a change in fuel system pressure following the application of vacuum.

5. The method of claim 4 , wherein the clutch is engaged to drive the vacuum pump to apply pressure to the fuel system.

6. The method of claim 4 , further comprising disengaging the clutch to deactivate the vacuum pump once a threshold fuel system pressure has been reached.

7. A method for an engine having a fuel system, comprising:
during an engine off condition, applying vacuum to the fuel system with a vacuum pump operated via an electric fan motor; and
indicating fuel system degradation in response to a change in fuel system pressure after a threshold level of vacuum has been applied by the vacuum pump.

8. The method of claim 7 , wherein applying vacuum to the fuel system with the vacuum pump operated via the electric fan motor further comprises engaging a clutch coupled to the motor in order to drive a shaft coupled to the vacuum pump.

9. The method of claim 7 , wherein the electric fan motor is operated during the engine off condition to cool the engine.

10. The method of claim 7 , wherein indicating fuel system degradation in response to the change in fuel system pressure includes indicating a fuel system leak based on an absolute rate of change in the fuel system pressure being higher than a threshold rate.

11. The method of claim 10 , wherein an orifice size of the fuel system leak is based on a difference between the absolute rate of change in the fuel system pressure and the threshold rate.

12. The method of claim 7 , wherein the fuel system pressure is a fuel tank pressure estimated by a pressure sensor coupled between a fuel tank and a canister of the fuel system.

13. The method of claim 7 , further comprising isolating the fuel system from atmosphere prior to applying vacuum to the fuel system.

14. A method for a fuel system of an engine, comprising:
following a key-off event, cooling the engine by operating an electric cooling fan;
applying vacuum to the fuel system by engaging a clutch coupled to a motor of the electric cooling fan, the clutch configured to transmit power from the motor to a vacuum pump; and
indicating fuel system degradation in response to a change in fuel system pressure following the application of vacuum.

15. The method of claim 14 , wherein the clutch is engaged to apply vacuum to the fuel system once the engine has cooled to a threshold temperature.

16. The method of claim 14 , further comprising, prior to monitoring the change in fuel system pressure, disengaging the clutch to deactivate the vacuum pump once a threshold pressure is reached.

17. The method of claim 14 , wherein indicating fuel system degradation in response to the change in fuel system pressure following application of pressure includes indicating a fuel system leak based on an absolute rate of change in the fuel system pressure being higher than a threshold rate.

18. The method of claim 17 , further comprising indicating a leak of a first size if the absolute rate of change in the fuel system pressure is a first rate, and indicating a leak of a second, greater size if the absolute rate of change in the fuel system pressure is a second, greater rate.

19. The method of claim 14 , wherein the fuel system pressure is a fuel tank pressure estimated by a pressure sensor coupled between a fuel tank and a canister of the fuel system.

Assignees

• Ford Global Tech Llc

Inventors

• Jentz Robert Roy
• Dudar Aed M

Classifications

• F02M25/0818 Primary

  having means for pressurising the evaporative emission space · CPC title

• F02M65/00

  Testing fuel-injection apparatus, e.g. testing injection timing {(testing of ignition F02P17/00; measuring fuel consumption G01F9/00); Cleaning of fuel-injection apparatus} · CPC title

• F02M65/006

  Measuring or detecting fuel leakage of fuel injection apparatus · CPC title

• F02M25/0809

  Judging failure of purge control system · CPC title