# US 8,751,135 B2 · Method to diagnose a fault in a fuel injection system of an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,751,135 B2 - Document ID: US8751135B2 - Status: Granted - Kind: B2 - Application number: 13/048,491 - Filed: 2011-03-15 - Published: 2011-09-15 - Granted: 2014-06-10 - Earliest claimed: 2010-03-15 - Assignees: GM Global Technology Operations LLC - Applicants: Marco Girotto; Tommaso De Fazio; Michele Bastianelli - Inventors: Marco Girotto; Tommaso De Fazio; Michele Bastianelli - Web page: https://patentgrep.com/patent/US8751135B2 ## CPC - F02D 41/221: {relating to the failure of actuators or electrically driven elements} - F02D 41/123: {the fuel injection being cut-off} - F02D 41/1497: {With detection of the mechanical response of the engine} - F02D 41/18: by measuring intake air flow - F02D 41/2438: {Active learning methods} - F02D 41/247: {Behaviour for small quantities} - F02D 2041/228: {Warning displays} - F02D 2200/1004: Estimation of the output torque - 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) ## Abstract A method is provided to diagnose a fault in a fuel injection system of an internal combustion engine. The method includes, but is not limited to commanding an injection pulse for injecting a test quantity of fuel into an engine cylinder, determining the torque released to an engine crankshaft due to the injection pulse, calculating the difference between this released torque and an expected value for the torque, and of detecting a fault in the fuel injection system if the difference exceeds a threshold. ## Claims ### Claim 1 A method of diagnosing a fault in a fuel injection system of an internal combustion engine, comprising: commanding an injection pulse for injecting a test quantity of fuel into a cylinder of the internal combustion engine; determining a torque released to a crankshaft of the internal combustion engine due to a combustion of said test quantity of fuel; calculating a difference between the torque and an expected torque value; and diagnosing the fault if said difference exceeds a threshold value. ### Claim 2 (depends on 1) The method according to claim 1, further comprising determining the expected torque value through an empirically determined map correlating the expected torque value with at least one operating parameters. ### Claim 3 (depends on 1) The method according to claim 1, wherein said commanding the injection pulse is conducted during a fuel cut-off phase of the internal combustion engine. ### Claim 4 (depends on 1) The method according to claim 1, wherein the test quantity of fuel is less than approximately 1 mm3. ### Claim 5 (depends on 1) The method according to claim 1, further comprising determining the torque as a function of a rotational speed variation of the crankshaft due to said injection pulse. ### Claim 6 (depends on 5) The method according to claim 5, further comprising measuring the rotational speed of the crankshaft with an encoder associated with the crankshaft. ### Claim 7 (depends on 1) The method according to claim 1, comprising performing an emergency procedure when the torque falls outside a torque range comprising the expected torque value. ### Claim 8 (depends on 7) The method according to claim 7, further comprising generating an alert signal when performing the emergency procedure. ### Claim 9 A computer readable medium embodying a computer program product, said computer program product comprising: a diagnostic program for diagnosing a fault in a fuel injection system of an internal combustion engine, the diagnostic program configured to: command an injection pulse for injecting a test quantity of fuel into a cylinder of the internal combustion engine; determine a torque released to a crankshaft of the internal combustion engine due to a combustion of said test quantity of fuel; calculate a difference between the torque and an expected torque value; and diagnose the fault if said difference exceeds a threshold value. ### Claim 10 (depends on 9) The computer readable medium embodying the computer program product according to claim 9, the diagnostic program further configured to determine the expected torque value through an empirically determined map correlating the expected torque value with at least one operating parameters. ### Claim 11 (depends on 9) The computer readable medium embodying the computer program product according to claim 9, wherein said command of the injection pulse is conducted during a fuel cut-off phase of the internal combustion engine. ### Claim 12 (depends on 9) The computer readable medium embodying the computer program product according to claim 9, wherein the test quantity of fuel is less than approximately 1 mm3. ### Claim 13 (depends on 12) The computer readable medium embodying the computer program product according to claim 12, the diagnostic program configured to determine the torque as a function of a rotational speed variation of the crankshaft due to said injection pulse. ### Claim 14 (depends on 13) The computer readable medium embodying the computer program product according to claim 13, the diagnostic program further configured to measure the rotational speed of the crankshaft with an encoder associated with the crankshaft. ### Claim 15 (depends on 9) The computer readable medium embodying the computer program product according to claim 9, the diagnostic program further configured to perform an emergency procedure when the torque falls outside a torque range comprising the expected torque value. ### Claim 16 (depends on 15) The computer readable medium embodying the computer program product according to claim 15, the diagnostic program further configured to generate an alert signal when performing the emergency procedure.