JP6790727B2 - Electronic control device - Google Patents

Description

The present invention relates to an electronic control device that controls fuel injection.

Conventionally, there is an electronic control device disclosed in Patent Document 1 as an example of an electronic control device that performs fuel injection control.

The electronic control device includes a voltage supply means for supplying a voltage to the fuel injection valve and a supply control means for controlling the supply timing by the voltage supply means. The voltage supply means electrically connects the booster circuit unit that boosts and outputs the power supply voltage, the capacitor provided between the booster circuit unit and the fuel injection valve, and the capacitor and the fuel injection valve by turning on. It has a discharging means to be used. Then, the supply control means calculates the capacity of the capacitor based on the discharge instruction unit that instructs the discharge means to turn on at a predetermined on timing, the voltage of the capacitor, and the current flowing through the capacitor, and uses the calculated capacitor capacity as the result. Based on this, a timing correction unit for correcting on-timing is provided.

Japanese Unexamined Patent Publication No. 2016-94444

At this point, it is conceivable that an aluminum electrolytic capacitor is used as the output capacitor of the booster circuit section. When a charging current flows when the aluminum electrolytic capacitor is charged by a boosted voltage, the charging voltage may jump up due to ESR (Equivalent Series Resistance), which is a DC resistance component of the aluminum electrolytic capacitor. Therefore, the electronic control device may consider that the charging is completed even though the charging voltage of the aluminum electrolytic capacitor has not actually reached the value considered to be charging completed, that is, it may erroneously detect.

As described above, when the electronic control device erroneously detects the completion of charging, the electronic control device stops the charging operation in a state where the charging voltage is low. Therefore, since the electronic control device performs injection in a state where the charging voltage is lowered, the injection accuracy is lowered, and the fuel consumption and the exhaust are deteriorated.

The present disclosure has been made in view of the above problems, and an object of the present invention is to provide an electronic control device capable of injecting fuel with high accuracy by suppressing erroneous detection of charging completion.

To achieve the above objectives, this disclosure is:
An electronic control device that controls fuel injection by turning the boost switch on and off to boost the battery voltage, charging the capacitor, and discharging the charging voltage of the capacitor to drive the fuel injection valve.
A booster (S10) that turns the boost switch on and off,
Detection units (S11, S12, S23, S32, S40) that detect the charging voltage,
It is provided with a determination unit (S13) for comparing the detected charging voltage with the target voltage and determining whether or not the charging voltage has reached the target voltage.
The detection unit sets the monitor timing to detect the charging voltage, and detects the charging voltage when the set monitor timing is reached. At least the timing at which the boost switch is switched from on to off is set as the monitor timing to boost the voltage. based on the drive signal of the boost switch by parts, the boost switch, wherein the judgment to Rukoto whether the timing switched from oN to oFF.

As described above, the present disclosure detects the charging voltage of the capacitor provided in parallel with the boost switch, compares the detected charging voltage with the target voltage, and determines whether or not the charging voltage has reached the target voltage. To do. The present disclosure, in order to detect the charge voltage at the timing when boost switch is switched from on to off can be suppressed to detect the charged voltage in a state in which the charging voltage jumped. Therefore, the present disclosure can suppress erroneous detection of charge completion and inject fuel with high accuracy.

The scope of claims and the reference numerals in parentheses described in this section indicate the correspondence with the specific means described in the embodiments described later as one embodiment, and the technical scope of the invention is defined. It is not limited.

It is a circuit diagram which shows the schematic structure of the system including the electronic control device in 1st Embodiment. It is a flowchart which shows the step-up process of the electronic control apparatus in 1st Embodiment. It is a flowchart which shows the timing setting process of the electronic control apparatus in 1st Embodiment. It is a time chart which shows the operation of the electronic control apparatus in 1st Embodiment. It is a flowchart which shows the timing setting process of the electronic control apparatus in 2nd Embodiment. It is a flowchart which shows the timing setting process of the electronic control apparatus in 3rd Embodiment.

In the following, a plurality of modes for carrying out the invention will be described with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding forms, and duplicate description may be omitted. In each form, when only a part of the process is described, the other part of the process can be applied with reference to the other forms described above.

(First Embodiment)
In this embodiment, an example in which the present invention is applied to the fuel injection control device 100 is adopted. The fuel injection control device 100 is mounted on a vehicle equipped with an engine.

As shown in FIG. 1, the fuel injection control device 100 is an electronic control device that drives and controls the first injector IN1 to the sixth injector IN6. That is, the fuel injection control device 100 controls the injection of fuel into the internal combustion engine by opening and closing each injector IN1 to IN6 according to the energization state of the actuators provided in each of the injectors IN1 to IN6. In the following, the fuel injection control device 100 will also be referred to as the ECU 100. The first injector IN1 to the sixth injector IN6 correspond to fuel injection valves within the scope of the claims. Since the injectors IN1 to IN6 are well-known techniques, detailed description thereof will be omitted.

In the ECU 100, the first injectors IN1 to 6th injectors IN6 provided in each cylinder of the engine are connected to the first terminal P1 to the sixth terminal P6 and the like. The first terminal P1 and the second terminal P2 are common terminals, the first injector IN1 is connected to the first terminal P1, and the fourth injector IN4 is connected to the second terminal P2. The third terminal P3 and the fourth terminal P4 are common terminals, the second injector IN2 is connected to the third terminal P3, and the fifth injector IN5 is connected to the fourth terminal P4. The fifth terminal P5 and the sixth terminal P6 are common terminals, the third injector IN3 is connected to the fifth terminal P5, and the sixth injector IN6 is connected to the sixth terminal P6.

The first injector IN1 is connected between the first terminal P1 and the seventh terminal P7. Similarly, the other injectors IN2 to IN6 are connected between the second terminal P2 to the sixth terminal P6 and the other terminal.

In the following, the common terminal to which the first injector IN1 and the fourth injector IN4 are connected will be referred to as a first common terminal. Similarly, in the following, the common terminal to which the second injector IN2 and the fifth injector IN5 are connected is the second common terminal, and the common terminal to which the third injector IN3 and the sixth injector IN6 are connected is the third common terminal. It is described as.

The ECU 100 includes a control IC 10, a microcomputer 20, a booster unit 30, a constant current supply unit 40, a temperature sensor 50, and the like. Further, the ECU 100 is configured to include discharge switches T15 to T17, a first cylinder switch T18, current detection resistors R11, R12, and the like.

Various input signals are input to the microcomputer 20 in the ECU 100. This input signal is engine operation information or the like detected by the sensor. The ECU 100 generates a command value for each cylinder by performing arithmetic processing by the microcomputer 20 using an input signal, and outputs the command value to the control IC 10. That is, the command value includes injection signals corresponding to each of the first injector IN1 to the sixth injector IN6. Then, in the ECU 100, the control IC 10 that has acquired each injection signal drives and controls the booster unit 30 and the injector.

Further, the microcomputer 20 receives a temperature signal, which is a sensor signal indicating the temperature, from the temperature sensor 50. The temperature sensor 50 outputs a signal corresponding to the temperature inside the ECU 100, that is, the temperature inside the case of the ECU 100. Therefore, the microcomputer 20 is configured to be able to acquire a temperature signal corresponding to the temperature inside the case.

A capacitor C11 is provided in the case of the ECU 100. Therefore, the temperature inside the case corresponds to the temperature of the environment in which the capacitor C11 is arranged.

The booster unit 30 includes a booster switch T11, a booster coil L11, a backflow prevention diode D11, and a capacitor C11. One end of the boost coil L11 is connected to the line of the battery voltage VB, and the other end is grounded via the boost switch T11. In the flowchart described later, the switch is also described as SW.

The first output port P20 of the control IC 10 is connected to the gate terminal of the boost switch T11, and is turned on and off according to the drive signal of the control IC 10. A capacitor C11 is connected between the step-up coil L11 and the step-up switch T11 as an energy storage means via a backflow prevention diode D11. Further, the boost switch T11 and the capacitor C11 are provided in parallel. The other end of the capacitor C11 is grounded. The boost switch T11 is grounded via the current detection resistor R11.

The control IC 10 outputs a drive signal from the first output port P20 to turn on and off the boost switch T11 to boost the battery voltage VB (boost processing). In other words, the control IC 10 performs the boost processing by setting the first output port P20 to high (H) and low (L). Further, the control IC 10 performs the step-up process in this way, and charges the capacitor C11 through the backflow prevention diode D11. In this way, it can be said that the booster unit 30 is composed of a DC-DC converter. It can be said that the ECU 100 generates the boosted voltage VBST by the battery voltage VB and the boosting unit 30.

As described above, the control IC 10 turns the boost switch T11 on and off to boost the battery voltage VB, and charges the capacitor C11 provided in parallel with the boost switch T11. Then, as will be described later, when the charging voltage reaches the target voltage, the control IC 10 discharges the fuel injection control to drive each of the injectors IN1 to IN6.

By the way, as the capacitor C11, an aluminum electrolytic capacitor is generally used. Therefore, when a charging current flows when the capacitor C11 is charged by the boosted voltage, the charging voltage may jump up due to the ESR which is a DC resistance component of the aluminum electrolytic capacitor.

Further, in the control IC 10, a current monitor port P21 is connected between the boost switch T11 and the current detection resistor R11, and monitors the current flowing through the boost switch T11. In other words, the control IC 10 detects the current flowing through the boost switch T11 via the current monitor port P21.

Further, in the control IC 10, a voltage monitor port P22 is connected between the cathode of the backflow prevention diode D11 and the capacitor C11 to monitor the voltage of the capacitor C11. In other words, the control IC 10 detects the charging voltage of the capacitor C11 via the voltage monitor port P22. Then, the control IC 10 controls the boost switch T11 on and off so that the charging voltage becomes a predetermined voltage while monitoring the charging voltage of the capacitor C11. As the step-up switch T11, a semiconductor switch such as a MOSFET can be adopted.

The discharge switches T15 to T17 are for discharging the condensers C11 to the injectors IN1 to IN6 to energize the injectors IN1 to IN6 to open the valve. The discharge switches T15 to T17 are connected to the second output port P23 of the control IC 10 to the gate terminal, and are turned on and off according to the drive signal of the control IC 10. That is, the control IC 10 outputs a drive signal from the second output port P23 to turn on and off the discharge switches T15 to T17, thereby energizing the injectors IN1 to IN6. In FIG. 1, for the sake of simplification of the drawing, the reference numerals of the second output port P23 to which the discharge switches T16 and T17 are connected are not given.

The discharge switch T15 is a discharge switch for the first injector IN1 and the fourth injector IN4 connected to the first common terminal. The discharge switch T16 is a discharge switch for the second injector IN2 and the fifth injector IN5 connected to the second common terminal. The discharge switch T17 is a discharge switch for the third injector IN3 and the sixth injector IN6 connected to the third common terminal.

For each of the discharge switches T15 to T17, a semiconductor switch such as a MOSFET can be adopted. The ECU 100 energizes the injectors IN1 to IN6 in order to open the injectors IN1 to IN6.

The constant current supply unit 40 is for supplying a peak current to the injectors IN1 to IN6 and then energizing the injectors IN1 to IN6 with a constant current lower than the peak current to maintain the valve open state. The constant current supply unit 40 includes constant current switches T12 to T14, reflux diodes D13, D15, D17, and backflow prevention diodes D12, D14, and D16.

The constant current switches T12 to T14 are turned on and off by the control IC 10. The control IC 10 turns on and off the constant current switches T12 to T14 in order to energize the injectors IN1 to IN6 with a constant current lower than the peak current. For each of the constant current switches T12 to T14, a semiconductor switch such as a MOSFET can be adopted.

The constant current switch T12, the reflux diode D13, and the backflow prevention diode D12 are constant current supply units for the first injector IN1 and the fourth injector IN4. The constant current switch T13, the reflux diode D15, and the backflow prevention diode D14 are constant current supply units for the second injector IN2 and the fifth injector IN5. The constant current switch T14, the reflux diode D17, and the backflow prevention diode D16 are constant current supply units for the third injector IN3 and the sixth injector IN6. The ECU 100 holds the valve open so that the fuel injection amount in each injector IN1 to IN6 becomes a target value, and energizes the injectors IN1 to IN6 with a constant current.

The injectors IN1 to IN6 are connected to the control IC 10 via a cylinder selection switch unit. For example, the cylinder selection switch unit for the first injector IN1 includes the first cylinder switch T18. As the first cylinder switch T18, a semiconductor switch such as a MOSFET can be adopted.

Further, the cylinder selection switch unit includes a current detection resistor R12 for detecting the current flowing through the injectors IN1 to IN6. For example, in the present embodiment, the current detection resistor R11 for detecting the drive current flowing through the first injector IN1 is provided. The control IC 10 has a current monitor port IIN connected to both terminals of the current detection resistor R11, and monitors the current flowing through the injectors IN1 to IN6. In other words, the control IC 10 detects the current flowing through the injectors IN1 to IN6 via the current monitor port IIN.

Here, the processing operation of the ECU 100 will be described with reference to FIGS. 1, 2, 3, and 4. Here, as an example, a case where the first injector IN1 is opened is adopted. The processing operation is the same when the other injectors IN2 to IN6 are opened. Note that FIG. 4 is a waveform at each port when the ECU 100 operates, and can be said to be a time chart showing the charging operation of the capacitor C11 in the ECU 100. In FIG. 4, the horizontal axis is time t.

First, in the ECU 100, when the first injector IN1 is energized, the control IC 10 turns on the discharge switch T15. When the discharge switch T15 is turned on, the ECU 100 supplies the energy stored in the capacitor C11 to the first injector IN1 and the fourth injector IN4 connected to the first common terminal. Further, the ECU 100 energizes the first injector IN1 by turning on the first cylinder switch T18 at the same time as the control IC 10 turns on the discharge switch T15. That is, the ECU 100 discharges the capacitor C11 to the first injector IN1 and supplies the peak current to the first injector IN1 to open the valve.

Further, in the ECU 100, after the peak current is energized, the control IC 10 turns off the discharge switch T15 and turns on the constant current switch T12 to energize the first injector IN1 with a constant current. More specifically, in the ECU 100, the control IC 10 turns the constant current switch T12 on and off according to the drive current flowing through the first injector 1, and energizes the first injector IN1 with a constant current lower than the peak current to open the valve. Hold the state. That is, the ECU 100 controls the first injector IN1 with a constant current. The ECU 100 drives the injectors IN1 to IN6 in this way to perform fuel injection control.

In this embodiment, as the constant current energization period for performing constant current control, an example is adopted in which the first constant current energization period at timings t2 to t4 and the second constant current energization period at timings t4 to t5 are provided. .. However, the present invention is not limited to this.

By the way, the capacitor C11 is in a fully charged state before the start of the peak current energization period before the timing t0. In that state, the ECU 100 turns on the discharge switch T15 and the first cylinder switch T18 during the period from timing t0 to t2 by the control IC 10. As a result, a peak current flows through the first injector IN1. On the other hand, the voltage of the capacitor C11 decreases. Since the ECU 100 monitors the voltage of the capacitor C11, it can detect that the voltage of the capacitor C11 has dropped to the charging start voltage.

When the control IC 10 detects that the voltage of the capacitor C11 has reached the charging start voltage, the control IC 10 performs a step-up process (S10). That is, the control IC 10 boosts the battery voltage VB by turning the boost switch T11 on and off. Then, the control IC 10 starts charging the capacitor C11 by the booster unit 30 by turning the boost switch T11 on and off. However, the voltage of the capacitor C11 continues to decrease until the timing t2 at which the peak current becomes maximum. In addition, step S10 corresponds to the boosting part in the claims.

Further, the control IC 10 determines whether or not it is the monitor timing (S11). When the control IC 10 determines that the monitor timing is reached, the control IC 10 monitors the charging voltage, that is, the voltage of the capacitor C11 (S12). In addition, steps S11 and S12 correspond to the detection part in the claims.

As will be described later, the monitor timing is set by the control IC 10 and is an arbitrary timing or an off timing of the step-up switch T11. By the way, the current flowing through the step-up switch T11 depends on the on / off (H, L of P20) of the step-up switch T11 as shown by the waveform of the current monitor port P21 in FIG. Therefore, when determining whether or not the boost switch T11 is off-timing, the control IC 10 can determine based on the current flowing through the boost switch T11. That is, the control IC 10 detects the current flowing through the boost switch T11 via the current monitor port P21, and when it reaches a predetermined value, it can determine that the boost switch T11 is off timing, that is, monitor timing.

Further, when determining whether or not the boost switch T11 is off-timing, the control IC 10 can determine whether or not the first output port P20 is H or L. That is, the control IC 10 can determine that the boost switch T11 is off timing, that is, monitor timing when the first output port P20 is switched from H to L.

Further, the control IC 10 determines whether or not the voltage of the capacitor C11 has reached the target voltage (S13). Then, when the control IC 10 determines that the voltage of the capacitor C11 has reached the target voltage, it considers that the charging of the capacitor C11 is completed and ends the process of FIG. As a result, the control IC 10 ends the step-up process.

On the other hand, when the control IC 10 determines that the voltage of the capacitor C11 has not reached the target voltage, it considers that the charging of the capacitor C11 is not completed, returns to step S10, and continues the boosting process. In addition, step S13 corresponds to the determination unit in the claims.

In this way, the control IC 10 monitors the voltage of the capacitor C11 and turns the boost switch T11 on and off to perform charging control so that the voltage of the capacitor C11 becomes the target voltage. It can be said that the control IC 10 performs charge control so as to be within the required voltage range including the target voltage.

As described above, when the capacitor C11 charged in this way is charged by the boosted voltage, the charging voltage may jump up due to the ESR when the charging current flows. Specifically, the charging voltage of the capacitor C11 jumps up during the period when P20 in FIG. 4 is L, that is, when the boost switch T11 is off. In particular, the lower the temperature of the environment in which the capacitor C11 is arranged, the more remarkable the jumping of the charging voltage becomes. Therefore, when the control IC 10 monitors the voltage of the capacitor C11 at the timing when the charging voltage jumps up, the charging is completed even though it is not in a state where it can be considered that the charging of the capacitor C11 is actually completed. If it is, it may be falsely detected.

Therefore, the control IC 10 sets the timing for monitoring the charging voltage of the capacitor C11 during charging. The control IC 10 performs the process shown in FIG. 3 at predetermined time intervals, for example, when power is supplied.

In step S20, the temperature is acquired (temperature acquisition unit). The control IC 10 acquires a temperature signal from the temperature sensor 50. The control IC 10 acquires a temperature signal in order to determine whether or not the temperature of the environment in which the capacitor C11 is arranged is a temperature at which the charge voltage of the capacitor C11 jumps significantly.

In step S21, it is determined whether or not the temperature is equal to or higher than the predetermined temperature. The control IC 10 determines whether or not the temperature of the environment in which the capacitor C11 is arranged is equal to or higher than a predetermined temperature based on the temperature signal acquired in step S20. The predetermined temperature is a temperature at which the charging voltage of the capacitor C11 jumps significantly, and can be set in advance based on the characteristics of the capacitor C11, experiments, and the like.

Then, when the control IC 10 determines that the temperature is equal to or higher than the predetermined temperature, it considers that the charging voltage of the capacitor C11 is unlikely to jump up, and proceeds to step S22. On the other hand, if the control IC 10 does not determine that the temperature is equal to or higher than the predetermined temperature, the control IC 10 considers that the charging voltage of the capacitor C11 is likely to jump up, and proceeds to step S23.

In step S23, the monitor timing is set to the off timing of the boost switch T11 (detection unit). That is, since the control IC 10 can be regarded as a situation in which the charging voltage of the capacitor C11 is likely to jump up, the monitor timing is set to the timing when the boost switch T11 is switched from on to off. The off timing here is the timing at which the boost switch T11 is switched from on to off.

As shown in FIG. 4, the voltage of the capacitor C11 does not jump up at the timing when the boost switch T11 is switched from on to off, that is, when P20 is switched from H to L. Alternatively, the voltage of the capacitor C11 does not jump up much at the timing when the boost switch T11 is switched from on to off. Thereby, the control IC 10 can set the monitor timing to a timing that is not easily affected by the jump even if the temperature is lower than the predetermined temperature.

Therefore, the control IC 10 detects the charging voltage of the capacitor C11 at the timing when the boost switch T11 is switched from on to off in step S11 (detection unit). That is, the control IC 10 starts detecting the charging voltage when the charging of the capacitor C11 starts, but only when the temperature is lower than the predetermined temperature, the charging voltage of the capacitor C11 is changed at the timing when the boost switch T11 is switched from on to off. Is detected.

In step S22, the monitor timing is set to an arbitrary timing. Since the control IC 10 can be regarded as a situation in which the charging voltage of the capacitor C11 is unlikely to jump up, the monitor timing is set to an arbitrary timing regardless of the on timing or the off timing of the boost switch T11. As this arbitrary timing, a preset timing or the like can be adopted.

In this way, the ECU 100 detects the charging voltage of the capacitor C11, which is an aluminum electrolytic capacitor provided in parallel with the boost switch T11, compares the detected charging voltage with the target voltage, and the charging voltage reaches the target voltage. Judge whether or not. Then, since the ECU 100 detects the charging voltage of the capacitor C11 at the timing when the boost switch T11 is switched from on to off, it is possible to suppress the detection of the charging voltage in the state where the charging voltage jumps up. Therefore, the ECU 100 can suppress erroneous detection of the completion of charging in the capacitor C11 and inject fuel with high accuracy.

Further, in order to prevent erroneous detection of charging completion due to the voltage jump in the capacitor C11, it is conceivable to increase the number of capacitors C11 and reduce the ESR. However, in this case, the cost of the ECU 100 increases as the capacitor C11 is increased, and the physique of the ECU 100 also increases. However, the ECU 100 can suppress erroneous detection of charging completion without increasing the capacitor C11. Therefore, the ECU 100 can suppress erroneous detection of charging completion while suppressing an increase in cost and an increase in physique.

In this embodiment, an example is adopted in which the monitor timing is set to the off timing of the boost switch T11 and the voltage of the capacitor C11 is monitored at the off timing of the boost switch T11. However, the present invention is not limited to this. In step S23, the control IC 10 may set the monitor timing while the boost switch T11 is on. That is, the control IC 10 sets the monitor timing to an arbitrary timing when the boost switch T11 is on. In this case, the control IC 10 detects the charging voltage of the capacitor C11 at an arbitrary timing when the boost switch T11 is turned on in step S11 (detection unit). This also makes it possible to achieve the same effect as described above. Further, this point can be adopted in other embodiments.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. The second embodiment and the third embodiment will be described below as other embodiments of the present invention.

(Second Embodiment)
The ECU 100 of the second embodiment is different from the first embodiment in that the control IC 10 performs the process shown in the flowchart of FIG. 5 and sets the monitor timing.

In the aluminum electrolytic capacitor, the jumping of the charging voltage may become remarkable not only by the temperature of the environment in which the capacitor is arranged but also by the elapsed time from the start of charging. Specifically, in the aluminum electrolytic capacitor, the longer the elapsed time from the start of charging, the more remarkable the jumping of the charging voltage becomes.

Therefore, the control IC 10 sets the timing for monitoring the charging voltage of the capacitor C11 at the time of charging based on the elapsed time from the start of charging. For example, when charging is started, the control IC 10 performs the process shown in FIG. 5 at predetermined time intervals. Further, the control IC 10 is configured to be able to acquire the elapsed time from the start of charging of the capacitor C11 (time acquisition unit). The control IC 10 can acquire the elapsed time by using, for example, a timer.

In step S30, the monitor timing is set to an arbitrary timing. Since the control IC 10 can be regarded as a situation in which the charging voltage of the capacitor C11 is unlikely to jump up, the monitor timing is set to an arbitrary timing regardless of the elapsed time from the start of charging or the like. As this arbitrary timing, a preset timing or the like can be adopted.

In step S31, it is determined whether or not a predetermined time has elapsed from the start of charging. The control IC 10 determines whether or not a predetermined time has elapsed from the start of charging in order to determine whether or not to change the monitor timing. The predetermined time is the elapsed time from the start of charging at which the charging voltage of the capacitor C11 jumps significantly, and can be set in advance based on the characteristics of the capacitor C11, experiments, and the like.

Then, when the control IC 10 determines that the predetermined time has not elapsed, it considers that the charging voltage of the capacitor C11 is unlikely to jump up, and repeats step S31. On the other hand, when the control IC 10 determines that the predetermined time has elapsed, it considers that the charging voltage of the capacitor C11 is likely to jump up, and proceeds to step S32.

In step S32, the monitor timing is set to the off timing of the boost switch T11 (detection unit). That is, since the control IC 10 can be regarded as a situation in which the charging voltage of the capacitor C11 is likely to jump up, the monitor timing is set to the timing when the boost switch T11 is switched from on to off. As a result, the control IC 10 can set the monitor timing to a timing that is not easily affected by the bounce even when a predetermined time has elapsed from the start of charging.

Therefore, the control IC 10 detects the charging voltage of the capacitor C11 at the timing when the boost switch T11 is switched from on to off (detection unit). That is, the control IC10 is only when a predetermined time has elapsed since charging started, detects the charging voltage of the capacitor C11 at the timing when the boost switch T11 is switched from ON to OFF. The ECU 100 of the second embodiment can exert the same effect as that of the first embodiment.

(Third Embodiment)
The ECU 100 of the third embodiment is different from the first embodiment and the second embodiment in that the control IC 10 performs the processing shown in the flowchart of FIG. The control IC 10 monitors the voltage of the capacitor C11 at the off timing of the boost switch T11 regardless of the temperature and the elapsed time from the start of charging. That is, in the control IC 10, the monitor timing is fixed to the off timing of the step-up switch T11.

Therefore, when the boosting process is started, the control IC 10 determines in step S40 whether or not the boosting switch T11 is off-timing (detection unit). Then, when the control IC 10 determines that the boost switch T11 is off-timing, it considers that the charging voltage of the capacitor C11 is unlikely to jump up, and proceeds to step S12. On the other hand, if the control IC 10 does not determine that the boost switch T11 is off-timing, the control IC 10 considers that there is a high possibility that the charging voltage of the capacitor C11 jumps up, and returns to step S10.

As a result, the ECU 100 of the third embodiment can exert the same effect as that of the first embodiment. Further, the ECU 100 of the third embodiment can suppress the erroneous detection of the completion of charging in the capacitor C11 and inject the fuel with high accuracy even when the erroneous detection of the temperature or the erroneous detection of the elapsed time occurs.

100 ... ECU, 10 ... Control IC, 20 ... Microcomputer, 30 ... Booster, 40 ... Constant current supply, C11 ... Capacitor, 50 ... Temperature sensor, T15 to T17 ... Discharge switch, T18 ... First cylinder switch, R11 ... Current detection resistor

Claims (5)

An electronic control device that controls fuel injection to drive a fuel injection valve by turning on and off a boost switch to boost the battery voltage to charge a capacitor and discharge the charging voltage of the capacitor.
A booster unit (S10) that turns the booster switch on and off, and
Detection units (S11, S12, S23, S32, S40) that detect the charging voltage, and
It is provided with a determination unit (S13) for comparing the detected charging voltage with the target voltage and determining whether or not the charging voltage has reached the target voltage.
The detection unit sets a monitor timing for detecting the charging voltage, and detects the charging voltage when the set monitor timing is reached, and at least the timing at which the boost switch is switched from on to off is the monitor. set as timing, on the basis of a drive signal of the boost switch by the booster unit, the electronic control device the boost switch you judged whether the timing is switched from oN to oFF. An electronic control device that controls fuel injection to drive a fuel injection valve by turning on and off a boost switch to boost the battery voltage to charge a capacitor and discharge the charging voltage of the capacitor.
A booster unit (S10) that turns the booster switch on and off, and
Detection units (S11, S12, S23, S32, S40) that detect the charging voltage, and
A determination unit (S13) that compares the detected charging voltage with the target voltage and determines whether or not the charging voltage has reached the target voltage.
It is equipped with a time acquisition unit that acquires the elapsed time from the start of charging.
The detection unit sets a monitor timing for detecting the charging voltage, and when the set monitor timing is reached, the detection unit detects the charging voltage, and the elapsed time acquired by the time acquisition unit elapses a predetermined time. An electronic control device that sets, as the monitor timing, the timing during which the boost switch is on or the timing at which the boost switch is switched from on to off is set as the monitor timing . The detection part, based on a current flowing through the boost switch, or is being turned on the boost switch, or claim 2, wherein the step-up switch to determine whether it is time switched from ON to OFF Electronic control device. Based on the drive signal of the booster switch by the booster unit, the detection unit determines whether the booster switch is on or the timing at which the booster switch is switched from on to off. Item 2. The electronic control device according to Item 2 . It is provided with a temperature acquisition unit (S20) that acquires the temperature of the environment in which the capacitor is arranged.
Wherein the detection unit, when before Symbol temperature is lower than the predetermined temperature, during the on of the boost switch, or electronic control according to the timing of the boost switch is switched from ON to OFF to claim 1, configured as the monitor timing apparatus.

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