# US 2019/0170081 A1 · Fuel injection control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170081 A1 - Document ID: US20190170081A1 - Status: Published application - Kind: A1 - Application number: 16/208,626 - Filed: 2018-12-04 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Ko KOMATSU - Web page: https://patentgrep.com/patent/US20190170081A1 ## CPC - F02D 41/402: {Multiple injections} - F02B 3/06: with compression ignition (compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02) - F02D 35/02: on interior conditions - F02D 41/403: {with pilot injections} - F02D 2041/389: {for injecting directly into the cylinder} - F02D 2200/0602: Fuel pressure - F02D 2200/0614: Actual fuel mass or fuel injection amount - F02D 2200/0616: determined by estimation - F02D 2250/04: Fuel pressure pulsation in common rails - F02M 57/005: {the devices being sensors} - 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 fuel injection control device includes a reference interval calculation section that calculates a reference interval between an end time of a decrease interval where the pressure decreases as a fuel injection rate increases and a start time of an increase interval where the pressure increases as the fuel injection rate decreases on a pressure waveform detected by the pressure sensor, an integration interval setting section that sets, in the reference interval, an integration interval where an influence of a disturbance on the fuel pressure decrease due to a target injection is suppressible, and a decrease amount calculation section that calculates a corresponding pressure decrease amount, which is a fuel pressure decrease amount corresponding to a maximum injection rate of fuel of the target injection, based on an integral value obtained by integrating the fuel pressure decrease amount due to the target injection in the integration interval. ## Claims ### Claim 1 A fuel injection control device applied to a fuel injection system including a pressure sensor that detects a pressure of fuel supplied to a fuel injection valve, the device comprising: a reference interval calculation section configured to calculate a reference interval between an end time of a decrease interval where the pressure decreases as a fuel injection rate increases and a start time of an increase interval where the pressure increases as the fuel injection rate decreases on a pressure waveform detected by the pressure sensor; an integration interval setting section configured to set, in the reference interval, an integration interval where an influence of a disturbance on the fuel pressure decrease due to a target injection is suppressible; and a decrease amount calculation section configured to calculate a corresponding pressure decrease amount, which is an amount of the fuel pressure decrease corresponding to a maximum injection rate of fuel of the target injection, based on an integral value obtained by integrating the amount of the fuel pressure decrease due to the target injection in the integration interval. ### Claim 2 (depends on 1) The fuel injection control device according to claim 1, wherein: the fuel injection system performs a multi-stage injection including a plurality of injections of fuel in one combustion cycle; the target injection is a succeeding injection following a preceding injection of the multi-stage injection; and the integration interval setting section is configured to set a length of the integration interval at a length equal to or larger than one period of a pressure pulsation waveform generated by the preceding injection. ### Claim 3 (depends on 2) The fuel injection control device according to claim 2, further comprising a waveform processing section configured to subtract a model waveform obtained by modeling the pressure pulsation waveform generated by the preceding injection from the pressure waveform detected by the pressure sensor in the target injection, wherein the decrease amount calculation section is configured to calculate the corresponding pressure decrease amount by using a pressure waveform obtained by subtracting the model waveform by the waveform processing section. ### Claim 4 (depends on 2) The fuel injection control device according to claim 2, wherein: the integration interval setting section is configured to set the length of the integration interval at a length of N period(s) of the pressure pulsation waveform; and N is a natural number. ### Claim 5 (depends on 1) The fuel injection control device according to claim 1, wherein: the fuel injection system further includes an accumulator vessel that stores fuel under high pressure; and fuel is supplied from the accumulator vessel to the fuel injection valve. ### Claim 6 (depends on 5) The fuel injection control device according to claim 5, wherein the integration interval setting section is configured to set the integration interval by excluding from the reference interval an opening disturbance interval between the end time of the decrease interval and a time corresponding to a first local maximum point of the pressure waveform generated after the decrease interval due to opening of the fuel injection valve. ### Claim 7 (depends on 5) The fuel injection control device according to claim 5, wherein the integration interval setting section is configured to set the integration interval by excluding from the reference interval an injection rate decrease interval between a predetermined time when the fuel injection rate starts to decrease from the maximum injection rate as a result of continuation of the target injection and the start time of the increase interval. ### Claim 8 (depends on 1) The fuel injection control device according to claim 1, wherein the integration interval setting section is configured to set the integration interval by excluding from the reference interval a drive interval where the fuel injection valve is driven. ### Claim 9 (depends on 1) The fuel injection control device according to claim 1, further comprising: a change index calculation section configured to calculate an aged change index indicating a degree of change of the corresponding pressure decrease amount calculated by the decrease amount calculation section due to aged change of the fuel injection valve; and an injection rate calculation section configured to calculate the maximum injection rate corresponding to the corresponding pressure decrease amount by using an initial maximum injection rate, which is the maximum injection rate in an initial state before the aged change of the fuel injection valve, and the aged change index. ### Claim 10 (depends on 9) The fuel injection control device according to claim 9, further comprising an abnormality determination section configured to determine abnormality of the fuel injection valve based on the aged change index. ### Claim 11 (depends on 1) The fuel injection control device according to claim 1, wherein: the fuel injection system is placed in a vehicle; and the corresponding pressure decrease amount is calculated every time a travel distance of the vehicle reaches a predetermined specified travel distance. ### Claim 12 A fuel injection control device applied to a fuel injection system including a pressure sensor that detects a pressure of fuel supplied to a fuel injection valve, the device comprising a control circuit configured: to calculate a reference interval between an end time of a decrease interval where the pressure decreases as a fuel injection rate increases and a start time of an increase interval where the pressure increases as the fuel injection rate decreases on a pressure waveform detected by the pressure sensor; to set, in the reference interval, an integration interval where an influence of a disturbance on the fuel pressure decrease due to a target injection is suppressible; and to calculate a corresponding pressure decrease amount, which is an amount of the fuel pressure decrease corresponding to a maximum injection rate of fuel of the target injection, based on an integral value obtained by integrating the amount of the fuel pressure decrease due to the target injection in the integration interval.