# US 2009/0260601 A1 · Fuel delivery system diagnostics after shut-down > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0260601 A1 - Document ID: US20090260601A1 - Status: Published application - Kind: A1 - Application number: 12/107,285 - Filed: 2008-04-22 - Published: 2009-10-22 - Earliest claimed: 2008-04-22 - Assignees: Ford Global Technologies, LLC - Inventors: Joseph Norman Ulrey; Ross Dykstra Pursifull; Diana D. Brehob - Web page: https://patentgrep.com/patent/US20090260601A1 ## CPC - F02D 41/3845: {by controlling the flow into the common rail, e.g. the amount of fuel pumped} - F02B 1/12: with compression ignition (with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00) - 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)} - F02M 63/022: {by acting on fuel control mechanism} - F02D 41/042: {for stopping the engine} - F02D 2041/224: {Diagnosis of the fuel system} - F02D 2041/225: {Leakage detection} - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## 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 ### Claim 1 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 comprising: 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. ### Claim 2 (depends on 1) The method of claim 1 wherein activation of one or more of the pumps includes activating and deactivating the lower pressure pump. ### Claim 3 (depends on 2) The fuel delivery system of claim 2 wherein the lower pressure pump is activated between 1 and 2 seconds. ### Claim 4 (depends on 1) The method of claim 1 wherein mitigating action is initiated based on a fuel rail pressure and temperature response profile. ### Claim 5 (depends on 4) The method of claim 4 wherein the pressure profile includes two or more measurements of the fuel in the fuel rail, and where the temperature profile includes two or more measurements of engine temperature. ### Claim 6 (depends on 5) The method of claim 5 wherein respective pairs of the temperature and pressure measurements are substantially concurrent. ### Claim 7 (depends on 1) The method of claim 1 wherein the lower pressure pump is a lift pump. ### Claim 8 (depends on 1) The fuel delivery system of claim 1 further comprising indicating an external leak when the fuel rail pressure drops below a threshold pressure and indicating an internal leak when the fuel rail pressure achieves at least the threshold value after or during the activation. ### Claim 9 (depends on 1) The method of claim 1 wherein the mitigating action includes adjusting an injection profile during the subsequent start based on the pressure response. ### Claim 10 (depends on 1) The method of claim 1 wherein the mitigating action includes setting a diagnostic code. ### Claim 11 (depends on 1) The method of claim 1 wherein the mitigating action includes delaying activation of a pump during the subsequent start. ### Claim 12 (depends on 1) The method of claim 1 wherein the mitigating action includes disabling both pumps during the subsequent start. ### Claim 13 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, and a fuel rail fluidly coupled downstream of the high pressure pump comprising: indicating a fuel system leak based on a fuel rail pressure response and a temperature response, the fuel rail pressure and temperature response occurring after an engine shut-down; and in response to the indication and before a subsequent engine start, the subsequent engine start occurring after the engine shut-down, activating and then deactivating the lower pressure pump; disabling vehicle operation if fuel rail pressure drops below a threshold value during or after the activation of the lower pressure pump; and adjusting operation of one of the pumps during the subsequent engine start if fuel rail pressure achieves at least the threshold value during or after the activation of the lower pressure pump. ### Claim 14 (depends on 13) The method of claim 13 where the fuel rail pressure and temperature response includes two or more substantially concurrent temperature and pressure measurements while the fuel system is in a closed volume state. ### Claim 15 (depends on 14) The method of claim 14 wherein the pressure measurements include a difference between a measured pressure, taken after the activation and deactivation of the lower pressure pump, and a previous pressure measurement. ### Claim 16 (depends on 15) The method of claim 15 wherein the previous pressure measurement includes a regulated pressure during a key-off condition. ### Claim 17 (depends on 13) The method of claim 13 further comprising indicating an external leak if fuel rail pressure drops below a threshold value during or after the activation of the lower pressure pump. ### Claim 18 (depends on 17) The method of claim 17 further comprising indicating an internal leak if fuel rail pressure achieves at least the threshold value during or after the activation of the lower pressure pump. ### Claim 19 A article of manufacture for controlling 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, and a fuel rail fluidly coupled downstream of the high pressure pump, the article comprising: code for indicating a fuel system leak based on a plurality of concurrent fuel rail pressure and temperature measurements, at least some of the fuel rail pressure and temperature measurements taken after an engine shut-down; and code for, in response to the indication and before a subsequent engine start, the subsequent engine start occurring after the engine shut-down, activating and then deactivating the lower pressure pump; code for disabling vehicle operation and indicating an external leak if fuel rail pressure drops below a threshold value during or after the activation of the lower pressure pump; and code for adjusting operation of one of the pumps during the subsequent engine start and indicating an internal leak if fuel rail pressure achieves at least the threshold value during or after the activation of the lower pressure pump. ### Claim 20 (depends on 19) The article of claim 19 further comprising code for setting a diagnostic code readable by a universal code reader, the setting responsive to each of the indication of a fuel leak, the indication of an internal leak, and the indication of the external leak. ### Claim 21 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: indicating a fuel system leak based on a fuel rail pressure response, the fuel rail pressure response occurring after an engine shut-down; in response to the indication and before a subsequent engine start, the subsequent engine start occurring after the engine shut-down, adjusting the solenoid valve; and differentiating whether the leak includes an internal or external leak based on fuel pressure response occurring after the solenoid valve is adjusted. ### Claim 22 (depends on 21) The method of claim 21 wherein the solenoid valve operates as a forward flow check valve in a first position, and an open valve in a second position, and where the adjusting the pump solenoid valve includes moving the pump solenoid valve to the first position from the second position. ### Claim 23 (depends on 22) The method of claim 22 where said differentiating includes identifying whether the fuel rail pressure drops below a threshold valve. ### Claim 24 (depends on 23) The method of claim 23 further comprising starting the engine after the differentiating, and when the 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.