# US 2018/0023501 A1 · Methods and system for a fuel system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0023501 A1 - Document ID: US20180023501A1 - Status: Published application - Kind: A1 - Application number: 15/215,620 - Filed: 2016-07-21 - Published: 2018-01-25 - Earliest claimed: 2016-07-21 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Pradheepram Ottikkutti; Bharath Chandrashekar; Shailesh Nair; Jeffrey David Willis - Web page: https://patentgrep.com/patent/US20180023501A1 ## CPC - F02D 41/3845: {by controlling the flow into the common rail, e.g. the amount of fuel pumped} - F02D 41/2438: {Active learning methods} - F02M 55/025: {Common rails} - F02M 59/466: {Electrically operated valves, e.g. using electromagnetic or piezoelectric operating means} - F16K 37/0083: {by measuring valve parameters} - F02D 41/123: {the fuel injection being cut-off} - F02D 2041/2058: {using information of the actual current value} - F02D 2041/224: {Diagnosis of the fuel system} - F02D 2200/0602: Fuel pressure - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)} ## Abstract Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a low-pressure pump operable to pump fuel from a fuel source at a first pressure, a high-pressure pump operable to increase the first pressure to a second pressure, a valve positioned between the low-pressure pump and the high-pressure pump and operable to control fuel flow to the high-pressure pump, a common fuel rail fluidly coupling the high-pressure pump to a plurality of fuel injectors coupled to cylinders of an engine, and a controller. The controller is operable to adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing. ## Claims ### Claim 1 A fuel system, comprising: a low-pressure fuel pump operable to pump fuel from a fuel source at a first pressure; a high-pressure fuel pump operable to increase the first pressure to a second pressure; a valve positioned between the low-pressure fuel pump and the high-pressure fuel pump, the valve being operable to control fuel flow to the high-pressure fuel pump; a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors that is operable to inject fuel to cylinders of an engine; and a controller operable to adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing. ### Claim 2 (depends on 1) The fuel system of claim 1, wherein the controller is operable to obtain the pre-firing correction factor by: opening the valve until a pre-firing pressure of the common fuel rail is reached; measuring valve electrical current at the pre-firing pressure; determining a first difference between the measured valve electrical current and a predicted valve electrical current, the predicted valve electrical current indicative of a predicted amount of valve electrical current to be supplied to the valve to reach the pre-firing pressure; and setting the valve pre-firing correction factor as the first difference. ### Claim 3 (depends on 2) The fuel system of claim 2, wherein the controller is operable to obtain the pre-firing correction factor during an engine start while the engine is rotating but no fuel injection is occurring. ### Claim 4 (depends on 2) The fuel system of claim 2, wherein the controller is operable to indicate a change in performance of one or more of the valve or high-pressure fuel pump if the first difference is greater than a threshold difference. ### Claim 5 (depends on 2) The fuel system of claim 2, wherein the controller is operable to, during cylinder firing conditions that include steady state engine operation at a given engine speed, given engine power, and given pressure of the common fuel rail, obtain a valve firing correction factor. ### Claim 6 (depends on 5) The fuel system of claim 5, wherein to obtain the valve firing correction factor, the controller is operable to: measure the valve electrical current at the given engine speed, given engine power, and given pressure; determine a second difference between the measured valve electrical current and a predicted valve electrical current, the predicted valve electrical current defining an amount of valve electrical current predicted to be supplied to the valve to reach the given pressure at the given engine speed; and set the valve firing correction factor as the second difference. ### Claim 7 (depends on 6) The fuel system of claim 6, wherein the controller is operable to further adjust the amount of valve electrical current supplied to the valve to reach the commanded pressure based on the valve firing correction factor. ### Claim 8 (depends on 6) The fuel system of claim 6, wherein the controller is operable to indicate a change in performance of the fuel system responsive to the second difference being greater than a threshold difference. ### Claim 9 (depends on 8) The fuel system of claim 8, wherein the controller is operable to adjust one or more engine operating parameters in response to the indication of the change in performance. ### Claim 10 (depends on 8) The fuel system of claim 8, further comprising an optical sensor positioned to detect a quantity of fuel, wherein the controller is operable to indicate the change in performance responsive to output from the optical sensor. ### Claim 11 A method for a fuel system for an engine, comprising: during a no-load condition of the engine while the engine is rotating, determining a first correction factor indicative of a difference between a first predicted position of a valve and a first measured position of the valve, the valve being operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail of the engine; during steady state engine operation, determining a second correction factor indicative of a difference between a second predicted position of the valve and a second measured position of the valve, the second predicted position of the valve based on the first correction factor; and responsive to an indication to perform a fuel system test, indicating a change in performance of the fuel system based on a difference between a third measured position of the valve and a threshold position, the threshold position based on both the first correction factor and second correction factor. ### Claim 12 (depends on 11) The method of claim 11, further comprising determining an age of the valve based on a rate of change of the first correction factor over a duration. ### Claim 13 (depends on 11) The method of claim 11, further comprising determining an age of one or more fuel injectors of the engine based on a rate of change of the second correction factor over a duration. ### Claim 14 (depends on 11) The method of claim 11, further comprising adjusting one or more engine operating parameters responsive to the change in performance of the fuel system. ### Claim 15 A method for a fuel system for an engine, the fuel system including a valve operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail of the engine, the method comprising: indicating a change in performance in the fuel system responsive to valve electrical current of the valve differing from a corrected valve electrical current threshold by more than a threshold amount, the corrected valve electrical current threshold including a base valve electrical current corrected with a first, pre-firing correction factor indicative of valve and/or fuel pump age and a second, firing correction factor indicative of fuel injector age. ### Claim 16 (depends on 15) The method of claim 15, further comprising correcting the base valve electric current with the first, pre-firing correction factor by opening the valve until a pre-firing pressure of the common fuel rail is reached, measuring valve electrical current at the pre-firing pressure, determining a first difference between the measured valve electrical current and the base valve electrical current, and correcting the base valve electrical current based on the first difference to reach a reference valve electrical current. ### Claim 17 (depends on 16) The method of claim 16, wherein correcting the base valve electric current with the first, pre-firing correction factor comprises correcting the base valve electric current with the first, pre-firing correction factor during an engine start while the engine is rotating but no fuel injection is occurring. ### Claim 18 (depends on 16) The method of claim 16, further comprising correcting the reference valve electrical current with the second, firing correction factor by measuring the valve electrical current at a given engine speed and given pressure of the common fuel rail; determining a second difference between the measured valve electrical current at the given engine speed and given pressure and the reference valve electrical current, and correcting the reference valve electrical current based on the second difference to reach the corrected valve electrical current threshold. ### Claim 19 (depends on 18) The method of claim 18, wherein correcting the reference valve electrical current with the second, firing correction factor comprises correcting the reference valve electrical current with the second, firing correction factor during cylinder firing conditions that include steady state engine operation at the given engine speed and the given pressure of the common fuel rail. ### Claim 20 (depends on 15) The method of claim 15, further comprising adjusting one or more engine operating parameters responsive to the change in performance of the fuel system.