Fuel delivery system diagnostics after shut-down

• US 7,762,234 B2
• Filed: 04/22/2008
• Issued: 07/27/2010
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ulrey, Joseph Norman, Brehob, Diana D., Pursifull, Ross Dykstra
• Primary Examiner(s): Cronin; Stephen K
• Assistant Examiner(s): VILAKAZI, SIZO BINDA
• Application Number:
  US12/107,285
• Publication Number:
  US 20090260601A1
• Time in Patent Office: 826 Days
• Field of Search: 123/458, 123/463, 123/479, 123/198.D, 123/518, 123/519, 123/520, 123/521, 123/359, 123/447, 123/456, 731/19.A, 73/40, 73/492, 73/493, 73/497, 73/491
• US Class Current: 123/456
• CPC Class Codes: F02B 1/12 with compression ignition with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00
• CPC Class Codes: F02D 2041/224 Diagnosis of the fuel system
• CPC Class Codes: F02D 2041/225 Leakage detection
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: F02M 63/022 by acting on fuel control mechanism

Abstract

A method for operation of a fuel delivery system in an internal combustion engine including a lower pressure pump, a higher pressure pump fluidly coupled downstream of the lower pressure pump, and a fuel rail fluidly coupled downstream of the high pressure pump. The method including initiating a mitigating action based on a fuel rail pressure response, the fuel rail pressure response occurring after an engine shut-down, where the mitigating action includes disabling vehicle operation if fuel rail pressure drops below a threshold value after activation of one of the pumps, the activation occurring before a subsequent engine start, the subsequent engine start occurring after the engine shut-down, and where the mitigating action includes adjusting operation of one of the pumps during the subsequent engine start if fuel rail pressure achieves at least the threshold value after or during the activation.

Claims

1. A method for operation of a fuel delivery system in an internal combustion engine having a fuel system including a lower pressure pump, a higher pressure pump fluidly coupled downstream of the lower pressure pump, a solenoid valve coupled between the higher and lower pressure pumps, and a fuel rail fluidly coupled downstream of the high pressure pump comprising:

stopping said internal combustion engine with said solenoid valve in a position that allows communication between said lower pressure pump and said higher pressure pump;

indicating a fuel system leak based on a fuel rail pressure response;

in response to the indication and before a subsequent engine start, the subsequent engine start occurring after stopping the internal combustion engine, adjusting the solenoid valve to a position that prevents communication between said lower pressure pump and said higher pressure pump; and

differentiating whether the fuel system leak includes an internal or external leak based on fuel pressure response occurring after the solenoid valve is adjusted.

2. The method of claim 1 wherein the lower pressure pump is activated and deactivated before measuring pressure of said fuel rail.

3. The method of claim 1 where said differentiating includes identifying whether pressure in the fuel rail drops below a threshold valve.

4. The method of claim 3 further comprising starting the internal combustion engine after the differentiating, and when the fuel system leak includes an external leak, identifying which injector leaks from a plurality of injectors based on a misfire of a corresponding cylinder during the start.