# US 8,783,230 B2 · Fuel injection system for internal-combustion engine and method of controlling fuel injection system for 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 8,783,230 B2 - Document ID: US8783230B2 - Status: Granted - Kind: B2 - Application number: 13/034,195 - Filed: 2011-02-24 - Published: 2011-09-15 - Granted: 2014-07-22 - Earliest claimed: 2010-03-09 - Assignees: Hitachi Automotive Systems, Ltd. - Applicants: Atsushi Okonogi; Masahiro Toyohara; Takashi Okamoto; Motoyuki Abe; Takuya Mayuzumi - Inventors: Atsushi Okonogi; Masahiro Toyohara; Takashi Okamoto; Motoyuki Abe; Takuya Mayuzumi - Web page: https://patentgrep.com/patent/US8783230B2 ## CPC - F02D 41/30: Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)} - F02D 41/20: Output circuits, e.g. for controlling currents in command coils - H03K 17/64: having inductive loads - F02D 41/402: {Multiple injections} - F02D 2041/2003: {using means for creating a boost voltage, i.e. generation or use of a voltage higher than the battery voltage, e.g. to speed up injector opening} - F02D 2041/2013: {by using a boost voltage source} - F02D 2041/2055: {with means for determining actual opening or closing time} - F02D 2200/503: Battery correction, i.e. corrections as a function of the state of the battery, its output or its type - 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) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract Disclosed is a fuel injection system that is used with an internal-combustion engine to reliably perform a requested fuel injection operation a requested number of times even when a boost voltage is lowered. The fuel injection system monitors the boost voltage immediately before the start of fuel injection, and varies a valve open time in accordance with the monitored boost voltage. Even when the boost voltage is lowered, the fuel injection system performs a fuel injection operation the requested number of times. ## Claims ### Claim 1 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and a injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage, and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection; time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve and the Ihold1 current is provided to complete the valve open action of the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open, and the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0. ### Claim 2 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and an injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open, the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0, and the controller has a predefined threshold value V1 at which a control signal is transmitted to decrease the number of multiple injections of the fuel injection valve or halt the fuel injection valve when there is a further decrease in the boost voltage. ### Claim 3 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and an injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage and an Ihold1 current generated by the boost voltage and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open, the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0, and the controller transmits a command signal concerning an injection time Ti, which starts simultaneously with the valve open time Pi of the fuel injection valve to keep the fuel injection valve open, to either the boost voltage driver or the battery voltage drive through the driver IC. ### Claim 4 (depends on 3) The engine control unit according to claim 3, wherein the controller includes a microcomputer. ### Claim 5 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and an injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open, the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0, and the engine control unit includes a fuel injection control circuit having the booster circuit, the boost voltage driver, the battery voltage drive and the driver IC. ### Claim 6 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and an injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open, the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0, and the driver IC includes a booster circuit drive section, which drives the booster circuit, and a driver drive section, which drives the boost voltage driver or the battery voltage driver. ### Claim 7 A method of controlling an engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the method comprising the steps of: outputting a valve open time for opening the fuel injection valve and a injection time for injecting the fuel injection valve; causing the engine control unit to monitor a boost voltage obtained by boosting the voltage of the battery; controlling the supply of an Ipeak current generated by the boost voltage, and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time; controlling the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time; the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open; and the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage is below a predefined normal voltage V0. ### Claim 8 (depends on 7) The method according to claim 7, further comprising the steps of: performing a first injection sequence by extending the valve open time Pi of the fuel injection valve when the boost voltage is below the predefined normal voltage V0; and performing a second injection sequence and subsequent injection sequences by decreasing the number of multiple injections of the fuel injection valve or by halting the multiple injections of the fuel injection valve. ### Claim 9 (depends on 7) The method according to claim 7, further comprising the step of: setting a boost voltage threshold value V1 at which the number of multiple injections of the fuel injection valve is decreased or the multiple injections of the fuel injection valve are halted when the boost voltage is below the predefined normal voltage. ### Claim 10 (depends on 9) The method according to claim 9, further comprising the step of: varying the boost voltage threshold value V1 when decreasing the number of multiple injections of the fuel injection valve or halting the multiple injections of the fuel injection valve. ### Claim 11 (depends on 7) The method according to claim 7, further comprising the step of: defining the timing of monitoring the boost voltage immediately before a fuel injection from the fuel injection valve. ### Claim 12 (depends on 7) The method according to claim 7, further comprising the steps of: monitoring at least one of internal-combustion engine fuel pressure, fuel injection valve injection interval, and internal-combustion engine temperature in addition to the boost voltage; and varying the valve open time Pi of the fuel injection valve in accordance with the monitored values. ### Claim 13 (depends on 1) The engine control unit according to claim 1, wherein the voltage driver further comprising a boost voltage driver which uses the boost voltage generated from the booster circuit to drive a load. ### Claim 14 (depends on 13) The engine control unit according to claim 13, wherein the voltage driver further comprising a battery voltage driver which uses the battery voltage generated from the battery to drive a load. ### Claim 15 (depends on 1) The engine control unit according to claim 1, wherein the extended valve open time Pi is provided such that an area enclosed by a current waveform of driving current of the fuel injection valve remains unchanged during the valve open time Pi. ### Claim 16 An engine control unit for an internal-combustion engine driving a fuel injection valve electromagnetically to provide fuel injection multiple number of times per operation cycle to a combustion chamber of the internal-combustion engine, the engine control unit comprising: a microcomputer outputting a valve open time for opening the fuel injection valve and an injection time for injecting the fuel injection valve; a booster circuit that boosts the voltage of the battery to generate a boost voltage for the engine control unit; a voltage driver which controls the supply of an Ipeak current generated by the boost voltage and an Ihold1 current generated by the boost voltage or the battery voltage smaller than the Ipeak current to the fuel injection valve according to the valve opening time, and controls the supply of an Ihold2 current generated by the battery voltage smaller than the Ihold1 current to the fuel injection valve according to the fuel injection time, wherein the Ipeak current and the Ihold1 current are predetermined to open the fuel injection valve, and the Ihold2 current is predetermined to hold the fuel injection valve open; and the valve open time is extended to control the providing current to the fuel injection valve to reach to the Ipeak current when the boost voltage of the booster circuit is below a predefined normal voltage V0, and the extended valve open time Pi is provided in inverse proportion to the boost voltage monitored before injection.