JP2016094844A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device suppressing the delay of stat timing of fuel injection.SOLUTION: An electronic control device includes: voltage supply means (12 and 20) for supplying voltage to a fuel injection valve; and supply control means (30) for controlling supply timing by the voltage supply means. The voltage supply means has a booster circuit portion (20) boosting and outputting power supply voltage, a capacitor (28) provided between the booster circuit portion and a fuel injection valve, and discharge means (12) which is turned on to electrically connect the capacitor and the fuel injection valve. The supply control means is equipped with a discharge instructing portion (32) which instructs turning-on to the discharge means at predetermined on-timing, and a timing correcting portion (30) which calculates the capacity of the capacitor on the basis of the voltage of the capacitor and a current flowing through the capacitor, and corrects the on-timing on the basis of the calculated capacity of the capacitor.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic control device that controls the operation of a fuel injection valve.

  Conventionally, as shown in Patent Document 1, for example, a fuel injection control device that controls an injector provided in each cylinder of an internal combustion engine has been proposed. The fuel injection control device includes a capacitor that supplies a high voltage to the solenoid valve, and a booster circuit that boosts the battery voltage and charges the capacitor. The fuel injection control device further includes a discharge switch provided in a current path that electrically connects the capacitor and the solenoid valve. MOSFET is applied to this discharge switch. The booster circuit has one current path that connects the battery and the capacitor, and another current path that branches from the one current path and connects to the ground. A boosting coil is provided in one current path, and a switching element for boosting is provided in the other current path. By switching the on / off state of the boosting switching element, the battery voltage is boosted by the boosting coil, which is applied to the capacitor, and the capacitor is charged with a high voltage. The high voltage charged in the capacitor is applied to the electromagnetic valve of the injector when the discharge switch is turned on. As a result, the solenoid valve is opened and fuel injection is started. After the fuel injection is started, at a predetermined application timing, not the voltage from the capacitor but the battery voltage is applied to the electromagnetic valve from another path, the open state of the electromagnetic valve is maintained, and the fuel injection is performed. Will continue. Thereafter, when application of the battery voltage is stopped, the electromagnetic valve is closed and fuel injection is stopped.

JP 2011-247185 A

  In the fuel injection control device disclosed in Patent Document 1, the capacity of a capacitor that supplies a high voltage to the solenoid valve changes due to durability deterioration, temperature characteristics, and the like because the solenoid valve is opened. For example, when the capacity of the capacitor is reduced due to durability deterioration, the voltage drop of the capacitor when the solenoid valve is opened increases. As a result, when the valve is opened, the voltage applied to the solenoid valve also drops greatly, so that the rise of the current flowing through the solenoid valve is delayed and the valve opening is delayed. As a result, the start of fuel injection is delayed, and there is a possibility that a predetermined amount of fuel cannot be injected in a predetermined period.

  In view of the above problems, an object of the present invention is to provide an electronic control device in which a delay in the start timing of fuel injection is suppressed.

  In order to achieve the above-described object, the present invention is an electronic control device for controlling the operation of the fuel injection valve (502), the voltage supply means (12, 20) for supplying a voltage to the fuel injection valve, Supply control means (30) for controlling the supply timing by the supply means, and the voltage supply means boosts the power supply voltage to generate a boosted voltage, and outputs the boosted voltage. By turning on the capacitor (28) provided between the circuit unit and the fuel injection valve, the capacitor and the fuel injection valve are electrically connected, and by turning off, the capacitor and the fuel injection valve are electrically connected. And a discharge instructing unit (32) for instructing the discharge unit to turn on at a predetermined on timing and to instruct to turn off at a predetermined off timing. , Capacitor voltage and A measuring unit (30) for measuring the current flowing through the capacitor, and calculating the capacitance of the capacitor based on the voltage of the capacitor measured by the measuring unit and the current flowing through the capacitor. Based on the calculated capacitor capacity, the on timing is calculated. And a timing correction unit (30) for correction.

  As described above, according to the present invention, the capacitance of the capacitor is calculated by the timing correction unit, and the on-timing can be corrected based on the calculated capacitor capacitance. That is, at the ON timing corresponding to the capacity of the capacitor, the discharging means is turned on, the capacitor starts discharging, and the voltage charged in the capacitor can be started to be applied to the fuel injection valve.

  Therefore, according to the present invention, even when the capacity of the capacitor is reduced due to deterioration over time or the like, and the fuel injection start timing is delayed, the fuel discharge start timing is corrected by correcting the on-timing. A delay in the injection start timing can be suppressed.

1 is an overall configuration diagram of an electronic control device according to a first embodiment and an internal combustion engine to which the electronic control device is applied. It is a block diagram of the electronic control apparatus shown in FIG. It is the flowchart which showed a series of processes performed with the electronic controller shown in FIG. FIG. 4 is a flowchart showing a series of processes executed in a normal control process (S103) in the flowchart shown in FIG. It is the flowchart which showed a series of processes performed by the correction control process (S104) in the flowchart shown in FIG. 2 is a time chart showing the operation of each component when a normal control process is executed in the electronic control device shown in FIG. 1. 2 is a time chart showing the operation of each component when a correction control process is executed in the electronic control device shown in FIG. 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the overall configuration of the electronic control device 100 according to the present embodiment and the internal combustion engine 500 in which it is used will be described. As shown in FIG. 1, the electronic control unit 100 is a device that controls fuel injection of an injector 502 that directly injects fuel into the combustion chamber 501 of an arbitrary cylinder of the internal combustion engine 500. The injector 502 corresponds to the fuel injection valve described in the claims.

  The fuel stored in the fuel tank 601 is supplied to the injector 502 via the low pressure fuel pump 602 and the high pressure fuel pump 603. Specifically, the fuel stored in the fuel tank 601 is supplied to the high-pressure fuel pump 603 at a low pressure by the low-pressure fuel pump 602, and the high-pressure fuel pump 603 receiving the fuel supplies the fuel to the injector 502 with a high pressure. . The injector 502 directly injects the supplied fuel into the combustion chamber 501 in accordance with the voltage applied from the electronic control device 100.

  The electronic control device 100 receives the output signals of the cam angle sensor 503 and the crank angle sensor 504 provided in the internal combustion engine 500, and based on these output signals, the electronic control device 100 detects the fuel injection timing, A voltage is applied to the injector 502. Then, the fuel is injected from the injector 502 by applying the voltage. The electronic control device 100 is supplied with a battery voltage VB from a battery 505.

  In FIG. 1, only one cylinder is shown. However, when the internal combustion engine 500 is, for example, a four-cylinder engine, an injector 502 is provided for each cylinder. Configured to apply a voltage.

  In the following description, the electronic control device 100 that controls the injector 502 provided in any one cylinder will be described. However, the same configuration is possible when controlling the injector 502 provided in each of a plurality of cylinders. is there.

  Next, the injector 502 according to the present embodiment and the electronic control device 100 that controls the injector 502 will be described with reference to FIG.

  The injector 502 includes an electromagnetic valve and an electromagnetic coil 502a that opens and closes the electromagnetic valve. Then, a voltage is applied from the electronic control device 100 to the electromagnetic coil 502a of the injector 502. By energization of this electromagnetic coil 502a, a valve element (not shown) moves to the valve opening position, and fuel injection is performed. When the energization of the electromagnetic coil 502a is interrupted, the valve body returns to the original closed position, and fuel injection is stopped.

  The electronic control device 100 has a VB terminal to which the battery voltage VB is applied, and has a constant current path Ll that electrically connects the VB terminal and the upstream terminal of the injector 502. A constant current switch 11 is provided in the constant current path Ll.

  Further, the electronic control device 100 has a boosting path Lh that is another path for electrically connecting the VB terminal and the upstream terminal of the injector 502. A booster circuit 20 that generates a boosted voltage applied to the injector 502 is provided in the booster path Lh, and the discharge switch 12 is provided between the booster circuit 20 and the injector 502.

  The electronic control device 100 also has a downstream path Lg that electrically connects the downstream terminal of the injector 502 and the ground. In the downstream path Lg, a downstream switch 13 and a resistor 14 for detecting a current flowing in the downstream path Lg are provided in series.

  As described above, the electronic control device 100 includes the constant current switch 11, the discharge switch 12, the downstream switch 13, and the booster circuit 20.

  Furthermore, the electronic control device 100 includes a microcomputer 30 that performs boost control of the boost circuit 20 and ON / OFF control of the constant current switch 11, the discharge switch 12, and the downstream switch 13.

  When the constant current switch 11 is turned on, the VB terminal and the upstream terminal of the injector 502 are electrically connected. When the constant current switch 11 is turned off, the constant current switch 11 is electrically disconnected. The discharge switch 12 is turned on to electrically connect the output terminal of the booster circuit 20 and the upstream terminal of the injector 502, and is turned off to electrically cut off both. When the downstream switch 13 is turned on, the downstream terminal of the injector 502 is electrically connected to the ground, and when it is turned off, the downstream switch 13 is electrically disconnected. Therefore, when the constant current switch 11 and the downstream switch 13 are turned on, the battery voltage VB is applied to the injector 502 and current flows. When the discharge switch 12 and the downstream switch 13 are turned on, the output voltage of the booster circuit 10 is applied to the injector 502, and a current flows. As the constant current switch 11, the discharge switch 12, and the downstream switch 13, for example, a MOSFET is applied.

  The booster circuit 20 receives the battery voltage VB, outputs a boosted voltage obtained by boosting the battery voltage VB, a second energization path 22 that branches from the first energization path 21 and is connected to the ground. And a third energization path 23.

  The first energization path 21 is provided with a coil 24 to which the battery voltage VB is applied at one end, and the other end of the coil 24 is electrically connected to the second energization path 22. In the second energization path 22, a charging switch 25 that causes a current to flow through the coil 24 by being turned on and a resistor 26 for detecting a current that flows through the second energization path 22 are provided in series. The on / off control of the charging switch 25 is performed according to an instruction from the microcomputer 30. When the charge switch 25 is turned on / off, a counter electromotive force is generated in the coil 24. As the charge switch 25, for example, a MOSFET is applied.

  The first energization path 21 is provided with a backflow prevention diode 27 having an anode connected to the connection point between the first energization path 21 and the second energization path 22, and the cathode of the diode 27 is the third energization path. 23 is electrically connected. The third energization path 23 is provided with a capacitor 28 that is charged by the counter electromotive force generated in the coil 24. With this configuration, the voltage stored in the capacitor 28 is output as a boosted voltage through the first energization path. As the capacitor 28, for example, a ceramic multilayer capacitor or an electrolytic capacitor is applied.

  The microcomputer 30 is electrically connected to the constant current switch 11, the discharge switch 12, the downstream switch 13, and the charge switch 25, and instructs each of them to switch on / off. The microcomputer 30 generates an injection signal 31 according to the combustion cycle of the internal combustion engine, and turns on / off the constant current switch 11, the discharge switch 12, the downstream switch 13, and the charge switch 25 according to the injection signal. And a switching instruction unit 32 that instructs to switch off.

  The injection instructing unit 31 generates an injection signal that instructs the start and stop of fuel injection based on the output signals of the cam angle sensor 503 and the crank angle sensor 504 input to the microcomputer 30. This injection signal is input to the switching instruction unit 32. The switching instruction unit 32 switches on / off of the constant current switch 11, the discharge switch 12, the downstream switch 13, and the charging switch 25 based on the injection signal. A control signal for instruction is output.

  The microcomputer 30 is electrically connected to both ends of the resistor 14 in the downstream path Lg and both ends of the resistor 26 in the second energization path 22. The microcomputer 30 detects the voltage across the resistor 14 and calculates the current flowing through the downstream path Lg based on the voltage. Similarly, the microcomputer 30 detects the voltage across the resistor 26 and calculates the current flowing through the second energization path based on the voltage.

  Further, the microcomputer 30 is electrically connected to the cathode of the diode 27 and detects the voltage of the capacitor 28.

  Next, the operation of the electronic control device 100 according to this embodiment will be described.

  First, control of the voltage applied to the injector 502 will be described. FIG. 3 is a flowchart showing a series of processes executed by the microcomputer 30 for controlling the voltage applied to the injector 502. 4 and 5 are flowcharts showing a series of processes executed in the normal control process (S103) and the correction control process (S104) in the flowchart of FIG. 3, respectively. 6 and 7 are time charts showing an example of the operation of each component when the flowcharts of FIGS. 4 and 5 are executed, respectively. The flowcharts of FIGS. 3 to 5 will be described with reference to these time charts.

  The series of processes in FIG. 3 is repeatedly executed by the microcomputer 30. First, the microcomputer 30 determines whether the ignition switch of the engine 500 is on (S101). If it is determined that the ignition switch is not in the on state, that is, it is in the off state, the processing of the flowchart in FIG. 3 ends. On the other hand, when it is determined that the engine is on, the microcomputer 30 determines whether the engine 500 is idling (S102). If it is determined that the engine is not idling, the microcomputer 30 executes a normal control process (S103) in FIG. 4 to be described later, and ends the process in the flowchart in FIG. On the other hand, when it is determined that the vehicle is idling, the microcomputer 30 executes a correction control process (S104) shown in FIG. 5 to be described later, and finishes the process shown in the flowchart of FIG.

  In the normal control process S103, as shown in FIG. 4, the microcomputer 30 first sets the fuel injection amount based on the operating state of the engine 500 (S201). Next, the injection instruction unit 31 sets the timing tis of the injection start instruction based on the operating state of the engine 500 (S202). Specifically, the microcomputer 30 first calculates the reference injection start timing tisb based on the fuel injection amount and the engine speed. Then, a timing tis is set in consideration of the correction amount Δtis with respect to the reference injection start timing tisb, which is calculated in the correction control process of FIG. 5 described later. For example, when the correction amount Δtis is set, the timing that is advanced by the correction amount Δtis from the reference injection start timing tisb is set as the timing tis of the injection start instruction. On the other hand, when the correction amount Δtis is not set, the reference injection start timing tisb is set as the timing tis of the injection start instruction.

  Next, the injection instructing unit 31 sets an injection stop instruction timing tie according to the injection amount set in S201 and the injection start instruction timing set in S202 (S203).

  Next, the injection instruction unit 31 instructs the switching instruction unit 32 to start injection at the timing tis of the injection start instruction set in S202 (S204). Specifically, an injection signal that is a signal for instructing injection start and stop from the injection instruction unit 31 to the switching instruction unit 32 is changed from the off state to the on state. As a result, as shown in FIG. 6, the injection signal is turned on from off at the tis timing set in S202.

  In response to the injection signal being turned on, the switching instruction unit 32 instructs the constant current switch 11, the discharge switch 12, and the downstream switch 13 to turn on or off (S205). Specifically, the switching instruction unit 32 instructs the discharge switch 12 and the downstream switch 13 to turn on. As a result, as shown in FIG. 6, the discharge switch 12 and the downstream switch 13 are turned on, the boosted voltage is applied to the electromagnetic coil 502a of the injector 502, and the current flowing through the electromagnetic coil 502a increases rapidly. At this time, since the boosted voltage is the voltage of the capacitor 28, the voltage of the capacitor 28 decreases as a current flows through the electromagnetic coil 502a.

  When the current flowing through the electromagnetic coil 502a exceeds a predetermined valve opening current value, the electromagnetic valve moves toward the valve opening position. After that, when the electromagnetic valve is completely opened, the battery voltage VB is applied to the electromagnetic coil 502a and the opened state of the electromagnetic valve is maintained as in the step described later.

  Next, charging of the capacitor 28 whose voltage has dropped due to the current flowing through the electromagnetic coil 502a is started (S206). For example, the timing tc at which the voltage of the capacitor 28 is lower than the predetermined threshold Vth is applied as the charging start timing.

  As a specific charging method, first, when the charging switch 25 is turned on by an instruction from the microcomputer 30, the battery voltage VB is applied to the coil 24, and a current flows through the coil 24. Thereafter, when the charging switch 25 is turned off according to an instruction from the microcomputer 30, a counter electromotive force is generated in the coil 24 and the capacitor 28 is charged. The on / off switching of the charging switch 25 is performed until the voltage of the capacitor 28 reaches a predetermined boosted voltage, and charging is completed when the voltage of the capacitor 28 reaches the predetermined boosted voltage.

  Thereafter, the microcomputer 30 calculates the current i flowing through the electromagnetic coil 502a by measuring the downstream current Lg (S207). The microcomputer 30 determines whether or not the solenoid valve is completely opened based on the current i (S208). When it is determined that the valve is completely opened, the process proceeds to the next step S209, and when it is not determined that the valve is completely opened, the process returns to S207.

  In S209, since the solenoid valve is completely opened based on the determination in S208, the switching instruction unit 32 maintains the solenoid valve open state, so that the constant current switch 11, the discharge switch 12, and the downstream switch 13 are maintained. An instruction to turn on / off is issued (S209). Specifically, the switching instruction unit 32 first instructs the discharge switch 12 to turn off at the timing to when the electromagnetic valve is completely opened. Thereafter, in order to maintain the open state of the solenoid valve, the on / off instruction is repeatedly given to the constant current switch 11 so that the constant current flows through the electromagnetic coil 502a.

  Next, the injection instruction unit 31 turns the injection signal from on to off at the timing tie of the injection stop instruction (S210). In response to this, the switching instruction unit 32 instructs the constant current switch 11 and the downstream switch 13 to turn off. As a result, voltage application to the electromagnetic coil 502a is stopped, the electromagnetic valve is closed, and fuel injection is stopped. And the process of this flowchart is complete | finished.

  Next, the correction control process S104 shown in FIG. 5 will be described. First, the microcomputer 30 executes the processes from S301 to S305. Since the processing from S301 to S305 is the same as the processing from S201 to S205 described above, description thereof will be omitted.

  As a result, the boosted voltage stored in the capacitor 28 is applied to the electromagnetic coil 502a of the injector 502 at the timing tis, as in the processing of S201 to S205 described above. As a result, the current flowing through the electromagnetic coil 502a increases rapidly. While the boosted voltage is applied, the microcomputer 30 continues to measure the voltage vc (t) of the capacitor 28 and the current il (t) flowing through the electromagnetic coil 502a, and the measured voltage vc (t) and current il ( t) is stored in the microcomputer 30. Here, t indicates time. The current il (t) is measured by the microcomputer 30 measuring the downstream current Lg. In this embodiment, the measurement period is the entire period during which the boosted voltage is applied to the electromagnetic coil 502a, but may be a part thereof.

  Next, the microcomputer 30 determines whether or not the solenoid valve is completely opened based on the current il (t) (S307). When it is determined that the valve is completely opened, the process proceeds to the next step S308, and when it is not determined that the valve is completely opened, the process returns to S306.

  In S308, since the solenoid valve is completely opened based on the determination in S307, the switching instruction unit 32 maintains the solenoid valve open state, so that the constant current switch 11, the discharge switch 12, and the downstream switch 13 are maintained. An on / off instruction is given (S308). Specifically, the switching instruction unit 32 first instructs the discharge switch 12 to turn off at the timing to when the electromagnetic valve is completely opened. Thereafter, in order to maintain the open state of the solenoid valve, the on / off instruction is repeatedly given to the constant current switch 11 so that the constant current flows through the electromagnetic coil 502a.

  Next, the capacitance C of the capacitor 28 is calculated based on vc (t) and il (t) stored in the microcomputer 30, and the injection start instruction timing tis is corrected based on the calculated capacitance C (S309). ). First, a specific method for calculating the capacity C will be described. According to the law of conservation of energy, when the boosted voltage of the capacitor 28 is applied to the electromagnetic coil 502a, the energy lost by the capacitor 28 is equal to the output of the electromagnetic coil 502a.

  Here, ta and tb are arbitrary times. (Formula 2) is obtained by transforming (Formula 1).

  By the process of S306, the voltage vc (t) and the current il (t) measured while the boosted voltage of the capacitor 28 is applied to the electromagnetic coil 502a are stored in the microcomputer 30. Therefore, the capacitance C is calculated based on (Equation 2) using the voltage vc (t) and the current il (t) stored in the microcomputer 30.

  Next, the microcomputer 30 sets the correction amount Δtis for the reference injection start timing tisb calculated in S302 or S202 of FIG. 4 described above based on the calculated capacity C.

  Specifically, for example, the microcomputer 30 has a map showing the relationship between the capacitance C and the correction amount Δtis in advance, and calculates the correction amount Δtis based on this map and the calculated capacitance C in S309. To do. Thereafter, the timing correction amount Δtis is stored in the microcomputer 30.

  Next, the microcomputer 30 starts charging the capacitor 28 (S310). Since the process of charging the capacitor 28 is the same as S206 described above, a description thereof will be omitted.

  Next, the injection instruction unit 31 turns the injection signal from on to off at the timing tie of the injection stop instruction (S311). In response to this, the switching instruction unit 32 instructs the constant current switch 11 and the downstream switch 13 to turn off. As a result, voltage application to the electromagnetic coil 502a is stopped, the electromagnetic valve is closed, and fuel injection is stopped. And the process of this flowchart is complete | finished.

  In the above description, the case where the electronic control unit 100 controls the injector 502 provided in one cylinder has been described. However, the injector 502 provided in each of a plurality of cylinders, for example, four cylinders, is controlled. It can also be applied to the case where control is performed.

  Next, effects of the electronic control device 100 according to the present embodiment will be described. According to the electronic control unit 100, the microcomputer 30 can calculate the capacitance C of the capacitor 28, and can correct the timing tis of the injection start instruction based on the calculated capacitance C. That is, at the timing tis corresponding to the capacitance C, the discharge switch 12 is turned on, the capacitor 28 starts discharging, and the boosted voltage charged in the capacitor 28 can be started to be applied to the electromagnetic coil 502a.

  Therefore, according to the electronic control unit 100, even when the capacitance C of the capacitor 28 fluctuates due to aging deterioration or the like, and the fuel injection start timing fluctuates, the timing tis is corrected and the discharge start timing of the capacitor 28 is corrected. By correcting, fluctuations in the fuel injection start timing can be suppressed. Thereby, fuel injection can be performed with high accuracy, and fuel consumption can be improved.

  In particular, in the present embodiment 100, when the calculated capacity C becomes smaller than a predetermined threshold value, correction is performed to make the timing tis earlier. As a result, even when the capacity C of the capacitor 28 is reduced due to deterioration over time and the fuel injection start timing is delayed, the timing tis is corrected to correct the discharge start timing of the capacitor 28 earlier. In addition, it is possible to suppress a delay in the fuel injection start timing. Thereby, fuel injection can be performed with high accuracy, and fuel consumption can be improved.

  In the present embodiment, the measurement period of the voltage vc (t) and the current il (t) is the entire period during which the boosted voltage is applied to the electromagnetic coil 502a. Therefore, the capacitance C of the capacitor 28 can be calculated with higher accuracy than when the measurement period is a part of the period during which the boosted voltage is applied to the electromagnetic coil 502a. As a result, the timing tis can be corrected with higher accuracy, and fluctuations in the fuel injection start timing can be further suppressed.

  In the correction control process S104 in the present embodiment, the voltage vc (t) and the current il (t) are measured during the discharge of the capacitor 28, and the charging process 310 of the capacitor 28 is performed after the measurement is completed. That is, during the measurement of the voltage vc (t) and the current il (t), the charging process 310 of the capacitor 28 is not performed. As a result, it is not necessary to consider fluctuations in the voltage and charge of the capacitor 28 due to charging, and the mathematical formula for calculating the capacitance C becomes a simple calculation formula such as (Formula 2). Accordingly, since the calculation load of the capacity C is reduced, a microcomputer 30 having a low processing capability can be adopted, and the cost of the electronic control device 100 can be reduced.

  Further, the correction control process S104 in the present embodiment is executed after the microcomputer 30 determines that the engine 500 is idle (S102). That is, the correction control process S104 is executed in a state where the processing load of the microcomputer 30 in the idle state is low, not in a state where the processing load of the microcomputer 30 is high as in the case where the accelerator is depressed and the engine 500 is in a high output state. The Therefore, since the processing load is distributed, a microcomputer 30 having a low processing capability can be adopted, and the cost of the electronic control device 100 can be reduced.

(Other embodiments)
In the first embodiment, when the calculated capacity C becomes smaller than the predetermined threshold value, the correction is made to advance the timing tis, but the present invention is not limited to this. The microcomputer 30 may have a map indicating the relationship between the capacity C and the timing tis in advance, and the microcomputer may correct the timing tis based on the map and the calculated capacity C. As a result, the timing tis can be accurately corrected in accordance with the change in the capacitance C.

  In the first embodiment, the capacity C is updated every time the correction control process S104 is executed, but the present invention is not limited to this. For example, the capacity C may be updated only for the first correction control process S104 after the engine 500 is in an idle state. Further, when engine 500 is in an idle state, capacity C may be updated only in an arbitrary number of correction control processes S104. Thereby, the processing load of the microcomputer 30 can be reduced rather than updating the capacity C each time the correction control process S104 is executed.

  DESCRIPTION OF SYMBOLS 12 ... Discharge switch (discharge means), 20 ... Booster circuit (boost circuit part), 14 ... Resistance (measurement means), 24 ... Coil, 25 ... Charge switch (switching element), 26... Resistance (measuring means), 28... Capacitor, 30... Microcomputer (measuring means, supply control means, charge control unit, timing correction unit), 32. 502 ... injectors (fuel injection valves).

Claims (5)

An electronic control device for controlling the operation of the fuel injection valve (502),
Voltage supply means (12, 20) for supplying a voltage to the fuel injection valve;
Supply control means (30) for controlling the supply timing by the voltage supply means,
The voltage supply means includes
A boosting circuit unit (20) for boosting a power supply voltage to generate a boosted voltage and outputting the boosted voltage;
A capacitor (28) provided between the booster circuit section and the fuel injection valve;
Discharging means (12) for electrically connecting the capacitor and the fuel injection valve by turning on, and electrically disconnecting the capacitor and the fuel injection valve by turning off,
The supply control means includes
A discharge instructing section (32) for instructing the discharging means to turn on at a predetermined on timing and to instruct to turn off at a predetermined off timing;
A measuring unit (30) for measuring the voltage of the capacitor and the current flowing through the capacitor;
A timing correction unit (30) for calculating the capacitance of the capacitor based on the voltage of the capacitor measured by the measurement unit and the current flowing in the capacitor, and correcting the on-timing based on the calculated capacitor capacitance; An electronic control device comprising: The measurement unit sets a part or all of a period during which the discharge unit is on as a measurement period, measures the measurement period, the voltage of the capacitor and the current flowing through the fuel injection valve,
The timing correction unit calculates a capacity of the capacitor based on the voltage of the capacitor measured during the measurement period and a current flowing through the fuel injection valve, and corrects the on-timing based on the calculated capacitor capacity. The electronic control device according to claim 1. The booster circuit unit includes:
A coil (24) provided on a first energization path to which the power supply voltage is input and the boosted voltage is output; and the power supply voltage is supplied to one end;
A switching element (25) provided on a second energization path from the other end of the coil to a reference potential lower than the power supply voltage, and causing a current to flow through the coil by being turned on,
The capacitor is provided on a third energization path extending from a connection point between the first energization path and the second energization path to the reference potential, and is generated in the coil when the switching element is turned on / off. Charged with back electromotive force,
The supply control means includes a charge control unit (30) that controls charging of the capacitor by instructing the switching element to turn on and off,
The electronic control device according to claim 2, wherein the charging control unit controls charging of the capacitor so as to perform charging after the measurement period without charging the capacitor.   The electronic control device according to claim 2, wherein the measurement period is provided after the internal combustion engine is started and is in an idling operation state.   5. The electronic control device according to claim 1, wherein the timing correction unit performs correction to advance the on-timing when the calculated capacitor capacity is smaller than a predetermined capacity. 6.