# US 8,788,235 B2 · Method for diagnosing an actuator for a boost pressure 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 8,788,235 B2 - Document ID: US8788235B2 - Status: Granted - Kind: B2 - Application number: 12/789,941 - Filed: 2010-05-28 - Published: 2010-12-23 - Granted: 2014-07-22 - Earliest claimed: 2009-06-18 - Assignees: Robert Bosch GmbH - Applicants: Thomas Bleile; Thomas Oertel - Inventors: Thomas Bleile; Thomas Oertel - Web page: https://patentgrep.com/patent/US8788235B2 ## CPC - F02D 41/221: {relating to the failure of actuators or electrically driven elements} - F02B 39/16: Other safety measures for, or other control of, pumps - F02B 37/186: {Arrangements of actuators or linkage for bypass valves} - F02B 37/24: by using pumps or turbines with adjustable guide vanes - F02D 41/08: for idling (F02D41/06, F02D41/16 take precedence) - F02D 41/123: {the fuel injection being cut-off} - F02D 41/18: by measuring intake air flow - F02D 2041/288: {for performing a transformation into the frequency domain, e.g. Fourier transformation} - F02D 2200/0406: Intake manifold pressure - F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor - F02M 26/10: having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system - F02M 26/49: Detecting, diagnosing or indicating an abnormal function of the EGR system - Y02T 10/40: Engine management systems - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for diagnosing an actuator for a boost pressure system of an internal combustion engine, in which the actuator is controlled using a triggering signal, and a state variable of the boost pressure system which is at least an indirect function of the triggering signal is detected. The triggering signal is periodic, and a curve of the values of the state variable is analyzed with regard to at least one periodic characteristic. ## Claims ### Claim 1 A method for diagnosing an actuator for a boost pressure system of an internal combustion engine, comprising: controlling, by a control unit, the actuator using a triggering signal, the triggering signal being periodic at a selected frequency; detecting, by a sensor, a state variable of the boost pressure system which is at least an indirect function of the triggering signal, the state variable being periodic at the selected frequency; and analyzing, by the control unit, a curve of values of the state variable with regard to at least one periodic characteristic to determine whether a rate of response of the actuator to the triggering signal has at least a predetermined threshold value. ### Claim 2 (depends on 1) The method according to claim 1, wherein the at least one periodic characteristic includes at least one of an amplitude and a phase shift of the curve of the values. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: after the analyzing step, comparing the at least one periodic characteristic to a predetermined limit value. ### Claim 4 (depends on 1) The method according to claim 1, wherein the method is initiated when the internal combustion engine is in a steady state. ### Claim 5 (depends on 1) The method according to claim 1, wherein the method is carried out in an overrun or idle mode of the internal combustion engine. ### Claim 6 (depends on 1) The method according to claim 1, wherein the actuator is a throttle valve for controlling a fresh air flow supplied to the internal combustion engine, a valve for controlling an exhaust gas recirculation flow supplied to the internal combustion engine, a valve for controlling an exhaust gas flow supplied to an exhaust gas turbocharger, or an actuator for controlling a turbine geometry of an exhaust gas turbocharger. ### Claim 7 (depends on 1) The method according to claim 1, wherein the state variable of the boost pressure system represents a mass or volume flow of a fresh air flow supplied to the internal combustion engine, of an exhaust gas recirculation flow supplied to the internal combustion engine, of an exhaust gas flow discharged from the internal combustion engine, or of an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 8 (depends on 1) The method according to claim 1, wherein the state variable of the boost pressure system represents a pressure of a fresh air flow supplied to the internal combustion engine, of an exhaust gas recirculation flow supplied to the internal combustion engine, of an exhaust gas flow discharged from the internal combustion engine, or of an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 9 (depends on 2) The method according to claim 2, wherein the amplitude and the phase shift of the curve of the values are ascertained by a Fourier analysis. ### Claim 10 (depends on 1) The method according to claim 1, further comprising: monitoring the internal combustion engine to determine whether the internal combustion engine is in an overrun mode or an idle mode, wherein the controlling, detecting, and analyzing are part of a diagnosis process that is carried out responsive to determining in the monitoring step that the internal combustion engine is in the overrun mode or the idle mode. ### Claim 11 (depends on 1) The method according to claim 1, further comprising: determining, based on the analysis, whether there is a threshold degree of temporal correspondence between a change in the state variable and the periodicity of the triggering signal. ### Claim 12 A non-transitory computer-readable medium containing a computer program which when executed by a processor performs the following method for diagnosing an actuator for a boost pressure system of an internal combustion engine: controlling the actuator using a triggering signal, the triggering signal being periodic at a selected frequency; detecting a state variable of the boost pressure system which is at least an indirect function of the triggering signal, the state variable being periodic at the selected frequency; and analyzing a curve of values of the state variable with regard to at least one periodic characteristic to determine whether a rate of response of the actuator to the triggering signal has at least a predetermined threshold value. ### Claim 13 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the at least one periodic characteristic is compared to a predetermined limit value. ### Claim 14 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the internal combustion engine is in a steady state during the monitoring of the internal combustion engine. ### Claim 15 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the actuator is one of: a throttle valve for controlling a fresh air flow supplied to the internal combustion engine; a valve for controlling an exhaust gas recirculation flow supplied to the internal combustion engine; a valve for controlling an exhaust gas flow supplied to an exhaust gas turbocharger; and an actuator for controlling a turbine geometry of an exhaust gas turbocharger. ### Claim 16 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the state variable of the boost pressure system represents a mass or volume flow of at least one of: (a) a fresh air flow supplied to the internal combustion engine, (b) an exhaust gas recirculation flow supplied to the internal combustion engine, (c) an exhaust gas flow discharged from the internal combustion engine, or (d) of an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 17 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the state variable of the boost pressure system represents a pressure of at least one of: (a) a fresh air flow supplied to the internal combustion engine, (b) an exhaust gas recirculation flow supplied to the internal combustion engine, (c) an exhaust gas flow discharged from the internal combustion engine, or (d) an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 18 (depends on 12) The non-transitory computer-readable medium according to claim 12, wherein the at least one periodic characteristic includes at least one of an amplitude and a phase shift of the curve of the values. ### Claim 19 (depends on 18) The non-transitory computer-readable medium according to claim 18, wherein the amplitude and the phase shift of the curve of the values are ascertained by a Fourier analysis. ### Claim 20 A control unit for diagnosing an actuator for a boost pressure system of an internal combustion engine, comprising: an arrangement for controlling the actuator using a triggering signal, the triggering signal being periodic at a selected frequency; an arrangement for detecting a state variable of the boost pressure system which is at least an indirect function of the triggering signal, the state variable being periodic at the selected frequency; and an arrangement for analyzing a curve of values of the state variable with regard to at least one periodic characteristic to determine whether a rate of response of the actuator to the triggering signal has at least a predetermined threshold a sufficiently high value. ### Claim 21 (depends on 20) The control unit according to claim 20, wherein, the at least one periodic characteristic is compared to a predetermined limit value. ### Claim 22 (depends on 20) The control unit according to claim 20, wherein the internal combustion engine is in a steady state during monitoring of the internal combustion engine. ### Claim 23 (depends on 20) The control unit according to claim 20, wherein the actuator is one of: a throttle valve for controlling a fresh air flow supplied to the internal combustion engine; a valve for controlling an exhaust gas recirculation flow supplied to the internal combustion engine; a valve for controlling an exhaust gas flow supplied to an exhaust gas turbocharger; and an actuator for controlling a turbine geometry of an exhaust gas turbocharger. ### Claim 24 (depends on 20) The control unit according to claim 20, wherein the state variable of the boost pressure system represents a mass or volume flow of at least one of: (a) a fresh air flow supplied to the internal combustion engine, (b) an exhaust gas recirculation flow supplied to the internal combustion engine, (c) an exhaust gas flow discharged from the internal combustion engine, or (d) of an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 25 (depends on 20) The control unit according to claim 20, wherein the state variable of the boost pressure system represents a pressure of at least one of: (a) a fresh air flow supplied to the internal combustion engine, (b) an exhaust gas recirculation flow supplied to the internal combustion engine, (c) an exhaust gas flow discharged from the internal combustion engine, or (d) an exhaust gas flow supplied to an exhaust gas turbocharger. ### Claim 26 (depends on 20) The control unit according to claim 20, wherein the at least one periodic characteristic includes at least one of an amplitude and a phase shift of the curve of the values. ### Claim 27 (depends on 26) The control unit according to claim 26, wherein the amplitude and the phase shift of the curve of the values are ascertained by a Fourier analysis.