# US 9,435,280 B2 · End of motion detection circuit for diesel engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,280 B2 - Document ID: US9435280B2 - Status: Granted - Kind: B2 - Application number: 14/197,494 - Filed: 2014-03-05 - Published: 2015-09-10 - Granted: 2016-09-06 - Earliest claimed: 2014-03-05 - Assignees: Continental Automotive Systems, Inc. - Applicants: Continental Automotive Systems, Inc. - Inventors: Izcoati Emmanuel Sanchez Gonzalez; Sergio Garcia de Alba Garcin; Oscar Alexjandro Camacho; Rafael Cobas Asensio - Web page: https://patentgrep.com/patent/US9435280B2 ## CPC - F02D 41/20: Output circuits, e.g. for controlling currents in command coils - F02M 51/0617: {having two or more electromagnets} - F02M 65/005: {Measuring or detecting injection-valve lift, e.g. to determine injection timing} - F02D 2041/2041: {for controlling the current in the free-wheeling phase} - F02D 2041/2044: {using pre-magnetisation or post-magnetisation of the coils} - F02D 2041/2079: {the circuit having several coils acting on the same anchor} - 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 ## Abstract A detection circuit for a diesel injection valve includes a first threshold, a first comparator for receiving a BEMF signal from the valve and compare the BEMF signal to the first threshold, a filter for filtering the BEMF signal thereby providing a filtered BEMF signal, a second threshold, and a second comparator for comparing a difference between the BEMF signal and the filtered BEMF signal to the second threshold, indicating an end of motion of the valve. An output of the first comparator and an output of the second comparator are joined to define an output signal. The output signal is activated only when the BEMF signal is above the first threshold and when the difference between the BEMF signal and the filtered BEMF signal is greater than the second threshold. ## Claims ### Claim 1 A detection circuit for detecting end of motion of a diesel injection valve, the valve having a first coil for opening the valve and a second coil for closing the valve, the detection circuit comprising: a first threshold, a first comparator constructed and arranged to receive a back electromotive feedback (BEMF) signal from the valve and compare the BEMF signal to the first threshold, a filter constructed and arranged to filter the BEMF signal thereby providing a filtered BEMF signal, a second threshold, a second comparator constructed and arranged to compare a difference between the BEMF signal and the filtered BEMF signal to the second threshold, indicating an end of motion of the valve, wherein an output of the first comparator and an output of the second comparator are joined to define an output signal and wherein, the output signal is activated only when the BEMF signal is above the first threshold and when the difference between the BEMF signal and the filtered BEMF signal is greater than the second threshold, and a third comparator constructed and arranged to subtract the BEMF signal from a moving average of the filtered BEMF signal, thereby defining said difference. ### Claim 2 (depends on 1) The circuit of claim 1, wherein the filter is a low pass filter. ### Claim 3 (depends on 2) The circuit of claim 2, wherein the low pass filter comprises a capacitor and a resistor. ### Claim 4 (depends on 1) The circuit of claim 1, wherein the first threshold is voltage. ### Claim 5 (depends on 4) The circuit of claim 4, wherein the voltage is at least 3.6 volts. ### Claim 6 (depends on 1) The circuit of claim 1, wherein each of the first, second and third comparators is an operational amplifier. ### Claim 7 (depends on 6) The circuit of claim 6, wherein each of the first and second operational amplifiers is an open collector operational amplifier. ### Claim 8 (depends on 1) The circuit of claim 1, wherein at least one of the comparators is a MOSFET. ### Claim 9 (depends on 1) The circuit of claim 1 in combination with the valve and an engine control unit (ECU), wherein the ECU receives the activated output signal so as to synchronize control signals to the valve based on end of motion of the valve. ### Claim 10 A method of synchronizing output signals from an engine control unit (ECU) to a diesel injection valve, the valve having a first coil for opening the valve and a second coil for closing the valve, the method comprising: comparing a back electromotive feedback (BEMF) signal received from the valve to a first threshold, thereby defining a first output, filtering the BEMF signal thereby providing a filtered BEMF signal, detecting an end of motion of the valve by comparing a difference between the BEMF signal and the filtered BEMF signal to a second threshold, thereby defining a second output, joining the first output with the second output to define an output signal, activating the output signal only when the BEMF signal is above the first threshold and when the difference between the BEMF signal and the filtered BEMF signal is greater than the second threshold, receiving activated output signal at the ECU, synchronizing control signals sent by the ECU to the valve based on end of motion of the valve, wherein the detecting step includes subtracting the BEMF signal from a moving average of the filtered BEMF signal, thereby defining said difference. ### Claim 11 (depends on 10) The method of claim 10, wherein the step of filtering uses a low pass filter. ### Claim 12 (depends on 11) The method of claim 11, wherein the low pass filter comprises a capacitor and a resistor. ### Claim 13 (depends on 10) The method of claim 10, wherein the first threshold is voltage. ### Claim 14 (depends on 13) The method of claim 13, wherein the voltage is at least 3.6 volts. ### Claim 15 (depends on 10) The method of claim 10, wherein each of the comparing steps and the subtracting step includes using an operational amplifier. ### Claim 16 (depends on 10) The method of claim 10, wherein at least one of the comparing steps uses a MOSFET. ### Claim 17 (depends on 10) The method of claim 10, wherein each of the comparing steps and the subtracting step includes using an operational amplifier. ### Claim 18 A method of detecting end of motion of a diesel injection valve, the valve having a first coil for opening the valve and a second coil for closing the valve, the method comprising: comparing an back electromotive feedback (BEMF) signal received from the valve to a first threshold, thereby defining a first output, filtering the BEMF signal thereby providing a filtered BEMF signal, detecting an end of motion of the valve by comparing a difference between the BEMF signal and the filtered BEMF signal to a second threshold, thereby defining a second output, joining the first output with the second output to define an output signal, and activating the output signal only when the BEMF signal is above the first threshold and when the difference between the BEMF signal and the filtered BEMF signal is greater than the second threshold, wherein the detecting step includes subtracting the BEMF signal from a moving average of the filtered BEMF signal, thereby defining said difference.