# US 9,438,137 B2 · Method and device for operating a piezoelectric actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,137 B2 - Document ID: US9438137B2 - Status: Granted - Kind: B2 - Application number: 14/111,239 - Filed: 2012-03-16 - Published: 2014-05-08 - Granted: 2016-09-06 - Earliest claimed: 2011-04-14 - Assignees: Robert Bosch GmbH - Applicants: Guido Porten; Jan-Mathias Meng - Inventors: Guido Porten; Jan-Mathias Meng - Web page: https://patentgrep.com/patent/US9438137B2 ## CPC - H02N 2/0075: {Electrical details, e.g. drive or control circuits or methods} - F02D 41/2096: {for controlling piezoelectric injectors (drive and control circuit for piezoelectric devices in general H10N30/802)} - F02D 41/247: {Behaviour for small quantities} - F02D 2041/2065: {the control being related to the coil temperature} - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - 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 for operating a piezoelectric actuator which may be activated with the aid of an activation signal. The piezoelectric actuator is operable in a passive and in an active operating mode. The piezoelectric actuator is activated without a functional operating request if the piezoelectric actuator is in a passive operating mode. ## Claims ### Claim 1 A method for operating a piezoelectric actuator which is activated by an activation signal, the piezoelectric actuator being operable in an active and in a passive operating mode, the piezoelectric actuator being activated functionally in the active operating mode in response to a functional operating request, and being in the passive operating mode in an idle state caused by an absence of the functional operating request, the method comprising: activating the piezoelectric actuator in the passive operating mode without the functional operating request, in response to detecting at least one of the following: the piezoelectric actuator being in the passive operating mode for a predetermined period of time, and a temperature condition associated with the piezoelectric actuator being met, wherein activation of the piezoelectric actuator opens a valve, wherein the piezoelectric actuator is activated in the active operating mode such that the valve is opened in conjunction with an injection through the opened valve, and wherein the activation in the passive operating mode opens the valve without a corresponding injection. ### Claim 2 (depends on 1) The method as recited in claim 1, further comprising: ascertaining a temperature in an area of the piezoelectric actuator at two points in time to calculate a change in temperature; and determining, as the temperature condition, whether the change in temperature or a value derived from the change in temperature exceeds a predefined value. ### Claim 3 (depends on 2) The method as recited in claim 2, wherein the temperature is ascertained using a temperature detector. ### Claim 4 (depends on 2) The method as recited in claim 2, wherein the temperature is ascertained by calculating the temperature based on a model. ### Claim 5 (depends on 2) The method as recited in claim 2, further comprising: regularly checking whether the piezoelectric actuator is in the passive operating mode. ### Claim 6 (depends on 2) The method as recited in claim 2, wherein the predefined value is a temperature difference. ### Claim 7 (depends on 2) The method as recited in claim 2, wherein the predefined value is a temperature change rate. ### Claim 8 (depends on 2) The method as recited in claim 2, wherein the piezoelectric actuator is activated after a plurality of temperature changes exceeding the predefined value are detected. ### Claim 9 A device for operating a piezoelectric actuator which is activated by an activation signal, comprising: a detector to detect whether the piezoelectric actuator is operated in an active or a passive operating mode, wherein the active operating mode is in response to a functional operating request, and wherein the passive operating mode is an idle state caused by an absence of the functional operating request; and a control device configured to activate the piezoelectric actuator in the passive operating mode without the functional operating request, in response to detecting at least one of the following: the piezoelectric actuator being in the passive operating mode for a predetermined period of time, and a temperature condition associated with the piezoelectric actuator being met, wherein activation of the piezoelectric actuator opens a valve, wherein the piezoelectric actuator is activated in the active operating mode such that the valve is opened in conjunction with an injection through the opened valve, and wherein the activation in the passive operating mode opens the valve without a corresponding injection. ### Claim 10 An internal combustion engine, comprising: a piezoelectric actuator activated by an activation signal; and a device that operates the piezoelectric actuator, the device including a detector to detect whether the piezoelectric actuator is operated in an active or a passive operating mode, wherein the active operating mode is in response to a functional operating request, and wherein the passive operating mode is an idle state caused by an absence of the functional operating request; and a control device configured to activate the piezoelectric actuator in the passive operating mode without the functional operating request, in response to detecting at least one of the following: the piezoelectric actuator being in the passive operating mode for a predetermined period of time, and a temperature condition associated with the piezoelectric actuator being met, wherein activation of the piezoelectric actuator opens a valve, wherein the piezoelectric actuator is activated in the active operating mode such that the valve is opened in conjunction with an injection through the opened valve, and wherein the activation in the passive operating mode opens the valve without a corresponding injection. ### Claim 11 A method for operating a piezoelectric actuator which is activated by an activation signal, the piezoelectric actuator being operable in an active and in a passive operating mode, the piezoelectric actuator being activated functionally in the active operating mode in response to a functional operating request, and being in the passive operating mode in an idle state caused by an absence of the functional operating request, the method comprising: activating the piezoelectric actuator in the passive operating mode without the functional operating request, in response to detecting at least one of the following: the piezoelectric actuator being in the passive operating mode for a predetermined period of time, and a temperature condition associated with the piezoelectric actuator being met; ascertaining a temperature in an area of the piezoelectric actuator at two points in time to calculate a change in temperature; and determining, as the temperature condition, whether the change in temperature or a value derived from the change in temperature exceeds a predefined value. ### Claim 12 (depends on 11) The method as recited in claim 11, wherein the temperature is ascertained using a temperature detector. ### Claim 13 (depends on 11) The method as recited in claim 11, wherein the temperature is ascertained by calculating the temperature based on a model. ### Claim 14 (depends on 11) The method as recited in claim 11, further comprising: regularly checking whether the piezoelectric actuator is in the passive operating mode. ### Claim 15 (depends on 11) The method as recited in claim 11, wherein the predefined value is a temperature difference. ### Claim 16 (depends on 11) The method as recited in claim 11, wherein the predefined value is a temperature change rate. ### Claim 17 (depends on 11) The method as recited in claim 11, wherein the piezoelectric actuator is activated after a plurality of temperature changes exceeding the predefined value are detected.