JP2017008888A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a booster circuit in a control device of an internal combustion engine.SOLUTION: The control device of an internal combustion engine comprises: a battery 2; an electric device 4 including a solenoid 21 which has one end connected to the battery and the other end grounded via a switching element 55, and an operation body 22 which is driven between an initial position and a drive position by the solenoid; a diode 71 having an anode connected to the other end of the solenoid; a capacitor 60 which has one end connected to the cathode of the diode and the other end grounded; an injector 3 which is driven by receiving supply of electric power from the capacitor or the battery to drive; and a control part 35 controlling the switching element. The control part switches on and off of the switching element to boost the capacitor by counter electromotive force generated in the solenoid, when a voltage of the capacitor is less than a predetermined value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device that boosts a battery voltage and supplies the boosted battery voltage to an injector.

  As an injector for an internal combustion engine for an automobile, a valve body that is received in the nozzle so as to be displaceable between an open position and a closed position, and closes the fuel flow path in the nozzle in the closed position, and the valve body is attached to the closed position. One having a spring that biases and a solenoid that attracts the valve body toward the open position against the biasing force of the spring when energized is known. As a method for controlling such an injector, in order to increase the responsiveness at the time of valve opening, a high voltage is applied to the solenoid in the initial stage of valve opening to increase the valve opening speed of the valve body, and then the applied voltage is decreased to reduce the valve There is a technique for maintaining a body in an open position (for example, Patent Document 1). A control device that controls the injector includes a booster circuit (boost chopper) including a coil, a capacitor, and a switching element in order to apply a high voltage to the injector. The booster circuit turns on and off the switching element to turn on and off the current supplied from the battery to the coil, and supplies the counter electromotive force generated in the coil to the capacitor to generate a voltage higher than the voltage of the battery.

JP 2012-145119 A

  However, when a booster circuit is provided in the control device, the size of the device and the cost increase become problems. In particular, since the coil of the booster circuit is a relatively large member, there is a desire to reduce the size. The control device according to Patent Document 1 uses a high-pressure pump control solenoid, and regenerates the back electromotive force generated when the high-pressure pump control solenoid is switched from on to off in a booster circuit. While reducing the flowing current in a short time, energy efficiency is improved. However, the control device according to Patent Document 1 is intended for effective use of the back electromotive force generated incidentally during normal use of the high pressure pump control solenoid, and actively uses the high pressure pump control solenoid. It does not boost the voltage. Therefore, the high-pressure pump control solenoid is not a substitute for the coil of the booster circuit, and does not contribute to downsizing of the booster coil.

  In view of the above background, an object of the present invention is to downsize a booster circuit in a control device for an internal combustion engine.

  In order to solve the above problems, the present invention provides a battery (2), a solenoid (21) having one end connected to the battery and the other end grounded via a first switching element (55), An electric device (4) including an operating body (22) driven between an initial position and a driving position by the solenoid; and a first diode (71) having an anode connected to the other end of the solenoid; A capacitor (60) having one end connected to the cathode of the first diode and a grounded other end, an injector (3) driven by power supplied from the capacitor or the battery, and the first A control unit (35) for controlling the switching element, wherein the control unit turns on or off the first switching element when the voltage of the capacitor is less than a predetermined value. It continues Instead, characterized by boosting the capacitor by counterelectromotive force generated in the solenoid.

  According to this configuration, when the voltage of the capacitor becomes less than a predetermined value, the current supply to the solenoid of the electric device becomes intermittent, and the voltage of the capacitor is boosted using the counter electromotive force generated in the solenoid of the electric device. Therefore, there is no need to provide a dedicated coil for boosting, and the control device can be downsized. Also, when a dedicated coil for boosting is provided, the control device can be downsized by reducing the size of the coil.

  Further, in the above invention, the control unit is configured so that when the electric device is driven, the solenoid is supplied with a current equal to or higher than a first current value that can hold the operating body in a driving position. The first switching element may be switched on and off. Alternatively, the control unit may control the first switching element so that when the electric device is stopped, a current equal to or less than a second current value that can hold the operating body in an initial position is supplied to the solenoid. It is good to switch on and off.

  According to this configuration, boosting can be performed using the solenoid of the electric device without affecting the operation of the electric device, that is, the position of the operating body.

  In the above invention, the electric device, the first switching element, and the first diode may cooperate to form one set, and a plurality of sets may be provided.

  According to this configuration, the solenoids of the plurality of electric devices can be used for boost control.

  In the above invention, the control unit compares the voltage of the capacitor with a plurality of determination values set corresponding to each of the sets, and the voltage of the capacitor becomes less than the determination value. The first switching element included in the set may be switched on and off.

  According to this configuration, the determination value is set for each set of electric devices, and only the electric device for which the determination is satisfied boosts the capacitor, so that overcharging of the capacitor is suppressed. Since the back electromotive force generated from each set of solenoids changes in accordance with the self-inductance of each solenoid, appropriate charging can be performed by individually setting a determination value for each set.

  In the above invention, the determination value may be set smaller as the self-inductance of the solenoid increases.

  According to this configuration, it is possible to set an appropriate determination value according to each solenoid. The back electromotive force generated by each solenoid increases as the self-inductance increases. Therefore, the overcharge of the capacitor can be suppressed by reducing the determination value for a solenoid having a larger self-inductance.

  Further, in the above invention, when the fuel cut control for maintaining the injector in a valve-closed state for a predetermined period is being performed, the control unit performs the first switching even if the voltage of the capacitor becomes less than the determination value. It is preferable not to switch the element on and off.

  According to this configuration, since charging of the capacitor is stopped based on the presence or absence of fuel cut, it is possible to reliably suppress overcharging of the capacitor. When the fuel cut is performed, the power supply to the injector is stopped, so there is no power consumption of the capacitor and no charging is required.

  In the above invention, the coil (58) having one end connected to the battery and the other end grounded via the second switching element (51), and the anode connected to the other end of the coil And a second diode (59) having a cathode connected to one end of the capacitor.

  According to this configuration, the capacitor can be boosted by the boosting coil, so that the voltage of the capacitor is reliably boosted even when the solenoid of the electric device cannot be used for boosting the capacitor.

  According to the above configuration, the booster circuit can be downsized in the control device for the internal combustion engine.

1 is a configuration diagram of a control device for an internal combustion engine according to an embodiment. Cross section of injector Sectional drawing of the first and second electric devices Flow chart showing boost control by controller Flow diagram showing boost control by control unit (continuation of Fig. 4) The figure which shows the waveform at the time of pressure | voltage rise of the control apparatus of an internal combustion engine

  Hereinafter, an embodiment of a control device for an internal combustion engine of the present invention will be described in detail with reference to the drawings. The control device for an internal combustion engine according to the present embodiment controls an electric device such as an injector that performs fuel injection and an electromagnetic valve in an internal combustion engine of an automobile.

  As shown in FIG. 1, a battery 2, an injector 3, a first electric device 4, and a second electric device 5 are connected to the control device 1 for the internal combustion engine. In this embodiment, an example in which two electric devices 4 and 5 are connected to the control device 1 will be described. However, at least one electric device 4 and 5 may be connected, and the number can be arbitrarily set. it can. The battery 2 includes a rechargeable storage battery such as a lead storage battery, and has a battery voltage of 12 V, for example. The control device 1 supplies the battery voltage from the battery 2 to the injector 3 and the first and second electric devices 4 and 5, boosts the battery voltage to a predetermined overexcitation voltage, and supplies it to the injector 3.

  The injector 3 is used for a direct injection gasoline engine, for example, and injects fuel into a combustion chamber of the internal combustion engine. As shown in FIG. 2, the injector 3 includes a cylindrical housing 10, a nozzle 11 provided at one end of the housing 10, an injection hole 12 formed at the tip of the nozzle 11, and the housing 10 and the nozzle 11. Plunger 13 disposed and displaceable along the axial direction to the distal end side and proximal end side, valve body 13A formed at the distal end of plunger 13, spring 14 for urging plunger 13 toward the distal end side, and housing 10 It has a core (iron core) 15 provided on the base end side of the inside, and a solenoid 16 wound around the core 15. The plunger 13 closes the injection hole 12 in the valve body 13A when biased by the spring 14 and is positioned on the distal end side, and opens the injection hole 12 when positioned on the proximal end side against the biasing force of the spring 14. The base end of the housing 10 is connected to a high-pressure fuel pipe (not shown) provided with a fuel pump (not shown), and the interior of the housing 10 and the nozzle 11 is filled with high-pressure fuel.

  In the state where no current is supplied to the solenoid 16, the injection hole 12 is closed by the valve body 13A of the plunger 13 biased by the spring 14, and fuel is not injected. On the other hand, when a current is supplied to the solenoid 16, the core 15 is magnetized, whereby the plunger 13 is attracted toward the core 15 against the urging force of the spring 14, and the injection hole 12 is opened. Thereby, the high-pressure fuel in the nozzle 11 is injected from the injection hole 12.

  As shown in FIG. 3, the first and second electric devices 4 and 5 are solenoids 21 (the solenoid of the first electric device 4 is a first solenoid 21A and the solenoid of the second electric device 5 is a second solenoid 21B). And a plunger (actuator) 22 that is driven between an initial position and a drive position by a solenoid 21. In the present embodiment, the first and second electric devices 4 and 5 are configured as electromagnetic valves. The first and second electric devices 4 and 5 have the same configuration, and can be displaced to the housing 24 in which the flow path 23 is formed, the valve seat 25 formed in the middle of the flow path 23, and the housing 24. The plunger 22 is provided between the housing 24 and the plunger 22, and the plunger 22 is attached in a direction in which the valve body 22 A is seated on the valve seat 25. It has a spring 26 to be energized and a core 27 provided on the base end side of the plunger 22 of the housing 24. The solenoid 21 is wound around the core 27.

  In a state where no current is supplied to the solenoid 21, the plunger 22 is biased by the spring 26 and is located at an initial position where the valve body 22 </ b> A is seated on the valve seat 25. In a state where the valve body 22A is seated on the valve seat 25, the flow path 23 is closed. On the other hand, when current is supplied to the solenoid 21, the core 27 is magnetized, whereby the plunger 22 is attracted toward the core 27 against the urging force of the spring 26, the plunger 22 moves to the driving position, and the valve body. 22A leaves the valve seat 25. Thereby, the flow path 23 is opened and the fluid can be circulated. The drive position is determined by the plunger 22 biased by the core 27 abutting against the core 27 or the housing 24.

  In order to hold the plunger 22 in the driving position against the urging force of the spring 26, the minimum current value that needs to flow through the solenoid 21 is defined as a first current value (holding current value). That is, when the current flowing through the solenoid 21 is greater than or equal to the first current value, the plunger 22 is in the driving position. The maximum current value that can hold the plunger 22 in the initial position is set as the second current value. That is, when the current flowing through the solenoid 21 is equal to or less than the second current value, the plunger 22 is in the initial position. The second current value is lower than the first current value. The first current value and the second current value are determined for each of the electric devices 4 and 5.

  The 1st and 2nd electric devices 4 and 5 comprise electromagnetic valves, such as a purge valve and an EGR valve, for example. The purge valve is an electromagnetic valve provided in a pipe connecting the canister and the intake passage of the internal combustion engine. The EGR valve is an electromagnetic valve provided in a pipe connecting an exhaust passage and an intake passage of an internal combustion engine.

  The control device 1 includes first to third booster circuits 31 to 33, a drive circuit 34, a control unit 35, and first to seventh terminals 41 to 47. The battery 2 is connected to the first terminal 41, the injector 3 is connected to the second and third terminals 42, 43, the first electric device 4 is connected to the fourth and fifth terminals 44, 45, The second electric device 5 is connected to the sixth and seventh terminals 46 and 47. The first to third boosting circuits 31 to 33 and the driving circuit 34 include first to sixth switching elements 51 to 56 each including, for example, a MOSFET or an IGBT. The control unit 35 is configured by a microcomputer.

  A first booster circuit 31 and a drive circuit 34 are provided between the first terminal 41 and the second terminal 42. The first booster circuit 31 boosts the voltage of the battery 2 supplied from the first terminal 41 to an overexcitation voltage (for example, about 60 V) of the injector 3 and supplies the boosted voltage to the second terminal 42. The first booster circuit 31 includes a coil 58, a diode 59, a capacitor 60, and a first switching element 51. One end of the coil 58 is connected to the first terminal 41. One end of the first switching element 51 and the anode terminal of the diode 59 are connected to the other end of the coil 58. The other end of the first switching element 51 is grounded via a current measuring resistor 61. The gate of the first switching element 51 is connected to the control unit 35, and is turned on / off based on a command from the control unit 35. The cathode terminal of the diode 59 is connected to one end of the capacitor 60. The other end of the capacitor 60 is grounded.

  In the first booster circuit 31, the current flows from the battery 2 to the ground through the first terminal 41, the coil 58, and the first switching element 51 in this order while the first switching element 51 is on. When the first switching element 51 is switched off from this state, the energization to the coil 58 is cut off and a counter electromotive force is generated in the coil 58. The back electromotive force generated in the coil 58 is supplied to the capacitor 60 through the diode 59, and the voltage of the capacitor 60 is boosted. By repeatedly switching the first switching element 51 on and off, the capacitor 60 is repeatedly boosted by back electromotive force, and the voltage of the capacitor 60 is boosted to an overexcitation voltage higher than the battery voltage.

  The control unit 35 is connected to one end of the capacitor 60 and detects the voltage applied to the voltage measuring unit 35A for detecting the voltage of the capacitor 60 and the current measuring resistor 61, whereby the current flowing through the current measuring resistor 61 is detected. Has a current detection unit 35B.

  The drive circuit 34 connects one end of the capacitor 60 and the second terminal 42 via the second switching element 52, and is parallel to the first booster circuit 31 and the second switching element 52 via the third switching element 53. The first terminal 41 and the second terminal 42 are connected to each other. In addition, the drive circuit 34 grounds the third terminal 43 through the fourth switching element 54.

  The third switching element 53 is connected to the first terminal 41 at one end, connected to the second terminal 42 via the diode 63 at the other end, and connected to the control unit 35 at the gate. The diode 63 is connected to the third switching element 53 at the anode terminal and is connected to the second terminal 42 at the cathode terminal.

  The second terminal 42 is grounded via a freewheeling diode 64. Specifically, the portion between the second terminal 42 and the second and third switching elements 53 is grounded via the freewheeling diode 64. The free-wheeling diode 64 is connected to the second terminal 42 at the cathode terminal and grounded at the anode terminal.

  The fourth switching element 54 is connected to the third terminal 43 at one end, grounded via the current measurement resistor 65 at the other end, and connected to the control unit 35 at the gate. The fourth switching element 54 is connected at one end to the cathode terminal of the Zener diode 66 and at the gate to the anode terminal of the Zener diode 66. The control unit 35 includes a current detection unit 35 </ b> C that detects a current flowing through the current measurement resistor 65 by detecting a voltage applied to the current measurement resistor 65.

  The injector 3 is connected to the second terminal 42 at one end of the solenoid 16 and is connected to the third terminal 43 at the other end of the solenoid 16.

  In response to a command from the control unit 35, the second, third, and fourth switching elements 52, 53, and 54 are turned on and off, whereby electric power is supplied to the solenoid 16 of the injector 3. When the second, third, and fourth switching elements 52, 53, and 54 are all off, power is not supplied to the solenoid 16. When the second and fourth switching elements 52 and 54 are on and the third switching element 53 is off, the voltage of the capacitor 60 (overexcitation voltage) is applied to the solenoid 16. When the third and fourth switching elements 53 and 54 are on and the second switching element 52 is off, the voltage of the battery 2 is applied to the solenoid 16.

  The control unit 35 sets the fuel injection amount, the number of injections, and the injection timing of the injector 3 based on the detection signal of the crank angle sensor provided in the internal combustion engine or the accelerator pedal sensor of the vehicle. The third and fourth switching elements 52, 53, and 54 are controlled. In one fuel injection, the control unit 35 applies the voltage of the capacitor 60 to the solenoid 16 by turning on the second and fourth switching elements 52 and 54 and turning off the third switching element 53 in the initial stage of injection. . Thereafter, the voltage is applied from the battery 2 to the solenoid 16 by turning on the third and fourth switching elements 53 and 54 and turning off the second switching element 52.

  The second and third booster circuits 32 and 33 have the same configuration. The second booster circuit 32 includes a fourth terminal 44 connected to the first terminal 41 and a fifth terminal 45 connected to one end of the capacitor 60 via the diode 71 and connected to one end of the fifth switching element 55. And a current measuring resistor 72 connected to the other end of the fifth switching element 55 at one end and grounded at the other end. The diode 71 is connected to the fifth terminal 45 at the anode, and is connected to one end of the capacitor 60 at the cathode. The fifth switching element 55 is connected to the fifth terminal 45 at one end, grounded at the other end, and connected to the control unit 35 at the gate. The fourth terminal 44 is connected to one end of the first solenoid 21A of the first electric device 4, and the fifth terminal 45 is connected to the other end of the first solenoid 21A of the first electric device 4. The control unit 35 includes a current detection unit 35 </ b> D that detects a current flowing through the current measurement resistor 72 by detecting a voltage applied to the current measurement resistor 72. The second booster circuit 32 including the fifth switching element 55 and the diode 71 and the first electric motor 4 including the first solenoid 21A cooperate to form a circuit that boosts the voltage of the capacitor 60. Configure.

  The third booster circuit 33 is connected to the sixth terminal 46 connected to the first terminal 41 and to one end of the capacitor 60 via the diode 74 and to the seventh terminal 47 connected to one end of the sixth switching element 56. And a current measuring resistor 75 connected to the other end of the sixth switching element 56 at one end and grounded at the other end. The diode 74 is connected to the seventh terminal 47 at the anode and is connected to one end of the capacitor 60 at the cathode. The sixth switching element 56 is connected to the seventh terminal 47 at one end, grounded at the other end, and connected to the control unit 35 at the gate. The sixth terminal 46 is connected to one end of the second solenoid 21B of the second electric device 5, and the seventh terminal 47 is connected to the other end of the second solenoid 21B of the second electric device 5. The control unit 35 includes a current detection unit 35E that detects a current flowing through the current measurement resistor 75 by detecting a voltage applied to the current measurement resistor 75. The third booster circuit 33 including the sixth switching element 56 and the diode 74 and the second electric motor device 5 including the second solenoid 21B cooperate to form a set to boost the voltage of the capacitor 60. Configure.

  In the second booster circuit 32, the supply and interruption of power to the first solenoid 21A of the first electric device 4 is controlled by turning on and off the fifth switching element 55 in accordance with a command from the control unit 35. The When the fifth switching element 55 is on, the current from the battery 2 is supplied from the first terminal 41, the fourth terminal 44, the first solenoid 21A of the first electric device 4, the fifth terminal 45, the fifth switching element 55, It flows in order to the ground. In a state where a predetermined current flows through the first solenoid 21 </ b> A of the first electric device 4, a magnetic field is generated around the first solenoid 21 </ b> A, and the plunger 22 is positioned at the driving position against the biasing force of the spring 26. When the fifth switching element 55 is turned off from this state, a back electromotive force is generated in the first solenoid 21A of the first electric device 4, and this back electromotive force is supplied to one end side of the capacitor 60 through the diode 71. . Thereby, the voltage of the capacitor 60 is boosted. When a predetermined time elapses after the fifth switching element 55 is turned off, the counter electromotive force disappears, the current flowing through the first solenoid 21A becomes less than the predetermined current value, and the plunger 22 biases the spring 26. To move to the initial position.

  In the third booster circuit 33 as well as the second booster circuit 32, the sixth switching element 56 is turned on / off in response to a command from the control unit 35, so that the second solenoid 21 </ b> B of the second electric device 5 is turned on. The supply and cut-off of the power is controlled. When the sixth switching element 56 is on, the current from the battery 2 is supplied from the first terminal 41, the sixth terminal 46, the second solenoid 21B, the seventh terminal 47, the sixth switching element 56, It flows in order to the ground. In a state where a predetermined current flows through the second solenoid 21 </ b> B of the second electric device 5, a magnetic field is generated around the second solenoid 21 </ b> B, and the plunger 22 is positioned at the driving position against the biasing force of the spring 26. When the sixth switching element 56 is turned off from this state, a back electromotive force is generated in the second solenoid 21 </ b> B of the second electric motor 5, and this back electromotive force is supplied to one end side of the capacitor 60 through the diode 74. . Thereby, the voltage of the capacitor 60 is boosted. When a predetermined time elapses after the sixth switching element 56 is turned off, the counter electromotive force disappears, the current flowing through the second solenoid 21B becomes less than the predetermined current value, and the plunger 22 biases the spring 26. To move to the initial position.

  The control unit 35 outputs a command to the fifth and sixth switching elements 55 and 56 to open and close the flow path 23 according to the operating state of the internal combustion engine, and drives the first and second electric devices 4 and 5. To do. Further, the control unit 35 repeatedly switches on and off the fifth and sixth switching elements 56 in accordance with the voltage of the capacitor 60 by boost control, and is generated in the solenoid 21 of the first and second electric devices 4 and 5. The voltage of the capacitor 60 is boosted using the back electromotive force.

  The control unit 35 includes a fuel cut control unit 35F. The fuel cut control unit 35F stops the power supply to the injector 3 based on the signal from the accelerator pedal sensor or the signal from the crank angle sensor, maintains the injector 3 in a closed state, and stops fuel injection. . The fuel cut control unit 35F, for example, releases the depression of the accelerator pedal based on a signal from the accelerator pedal sensor, and the engine speed based on a signal from the crank angle sensor is a predetermined first threshold (for example, an idle speed). ) When larger, the fuel cut is turned on, that is, the power supply to the injector 3 is stopped. Further, the fuel cut control unit 35F turns on the fuel cut when the engine speed is equal to or higher than a predetermined second threshold value (upper limit speed) based on a signal from the crank angle sensor.

  An example of boost control of the capacitor 60 by the control unit 35 will be described with reference to the flowcharts of FIGS. 4 and 5. Steps S1 to S6 are processes for the first electric device 4 (second booster circuit 32). First, the control unit 35 detects the voltage of the capacitor 60 (hereinafter referred to as the capacitor voltage Vc) in the voltage detection unit 35A, and determines whether or not the capacitor voltage Vc is less than a predetermined voltage determination value V1 (S1). ). The voltage determination value V1 is set based on the self-inductance L1 of the first solenoid 21A of the first electric device 4, and the capacitor voltage Vc does not exceed a predetermined overexcitation voltage due to the counter electromotive force generated from the first solenoid 21A. Is set to If the determination in step S1 is No, the process proceeds to step S7 without boosting the capacitor 60 by the first solenoid 21A.

  When the determination in step S1 is Yes, the control unit 35 determines whether or not the fifth switching element 55 has failed in step S2. The determination is performed based on the command output from the control unit 35 to the fifth switching element 55 and the current value detected by the current detection unit 35D. The control unit 35 outputs an OFF command to the fifth switching element 55, and outputs an ON command to the fifth switching element 55 when the current detection unit 35D detects a current equal to or greater than a predetermined determination value. When the current detection unit 35D does not detect a current greater than or equal to a predetermined determination value, it is determined that the fifth switching element 55 is malfunctioning. If the determination in step S2 is Yes, the capacitor 60 is not boosted by the first solenoid 21A, a failure is output in step S6, and the process proceeds to step S7. The failure output may be displayed on, for example, an indicator on the instrument panel.

  If the determination in step S2 is No, it is determined in step S3 whether the fifth switching element 55 is on. This determination is performed based on a command output from the control unit 35 to the fifth switching element 55.

  When the fifth switching element 55 is on, in step S4, the control unit 35 alternately outputs an on / off command for the fifth switching element 55 and continuously turns on / off the fifth switching element 55. To switch. At this time, the control unit 35 switches the fifth switching element 55 with a relatively high duty ratio (high duty ratio) so that the current flowing through the first solenoid 21A of the first electric device 4 becomes equal to or higher than the first current value. . That is, even while the fifth switching element 55 is alternately turned on and off, the current flowing through the first solenoid 21A of the first electric device 4 is maintained at the first current value or more, and the plunger of the first electric device 4 22 is maintained in the driving position. Thereby, the operation state of the first electric device 4 does not change. Switching the fifth switching element 55 on and off changes the current flowing through the first solenoid 21 </ b> A of the first electric device 4, so that a back electromotive force is generated in the first solenoid 21 </ b> A of the first electric device 4. The back electromotive force generated in the first solenoid 21A of the first electric device 4 is supplied to the capacitor 60 through the diode 71 to boost the capacitor voltage Vc.

  If the determination in step S3 is No, that is, if the fifth switching element 55 is OFF, in step S5, the control unit 35 alternately outputs an ON / OFF command for the fifth switching element 55, and the fifth switching element 55 The element 55 is continuously switched on and off. At this time, the control unit 35 switches the fifth switching element 55 at a relatively low duty ratio (low duty ratio) so that the current flowing through the first solenoid 21A of the first electric device 4 is equal to or less than the second current value. . That is, even while the fifth switching element 55 is alternately turned on and off, the current flowing through the first solenoid 21A of the first electric device 4 is maintained below the second current value, and the plunger of the first electric device 4 22 is maintained at the initial position. Thereby, the operation state of the first electric device 4 does not change. Switching the fifth switching element 55 on and off changes the current flowing through the first solenoid 21 </ b> A of the first electric device 4, so that a back electromotive force is generated in the first solenoid 21 </ b> A of the first electric device 4. The back electromotive force generated in the first solenoid 21A of the first electric device 4 is supplied to the capacitor 60 through the diode 71 to boost the capacitor voltage Vc.

  After performing the step-up operation in step S4 or S5, the process proceeds to step S7. Steps S7 to S12 are processes for the second electric device 5 (third booster circuit 33), and the same processes as those in steps S1 to S6 are performed.

  The control unit 35 determines whether or not the capacitor voltage Vc is less than a predetermined voltage determination value V2 (S7). The voltage determination value V2 is set based on the self-inductance L2 of the second solenoid 21B of the second electric motor 5, and is a value that the capacitor voltage Vc does not exceed a predetermined overexcitation voltage due to the counter electromotive force generated from the second solenoid 21B. Is set to When the determination in step S7 is No, the process proceeds to step S13 without boosting the capacitor 60 by the second solenoid 21B.

  If the determination in step S7 is Yes, the control unit 35 determines in step S8 whether or not the sixth switching element 56 has failed. The determination is the same as the processing in step S2, and is performed based on the command output from the control unit 35 to the sixth switching element 56 and the current value detected by the current detection unit 35E. If the determination in step S8 is Yes, the capacitor 60 is not boosted by the second solenoid 21B, a failure is output in step S12, and the process proceeds to step S13.

  If the determination in step S8 is No, it is determined in step S9 whether the sixth switching element 56 is on. When the sixth switching element 56 is on, in step S10, the control unit 35 alternately outputs an on / off command for the sixth switching element 56 and continuously turns on / off the sixth switching element 56. To switch. At this time, the control unit 35 switches the sixth switching element 56 with a relatively high duty ratio (high duty ratio) so that the current flowing through the second solenoid 21B of the second electric device 5 becomes equal to or higher than the first current value. . As a result, the back electromotive force generated in the second solenoid 21B of the second electric device 5 is supplied to the capacitor 60 through the diode 74 and boosts the capacitor voltage Vc.

  If the determination in step S9 is No, that is, if the sixth switching element 56 is off, in step S11, the control unit 35 alternately outputs an on / off command for the sixth switching element 56, and the sixth switching element 56 The element 56 is continuously switched on and off. At this time, the control unit 35 switches the sixth switching element 56 with a relatively low duty ratio (low duty ratio) so that the current flowing through the second solenoid 21B of the second electric device 5 becomes equal to or less than the second current value. . As a result, the back electromotive force generated in the second solenoid 21B of the second electric device 5 is supplied to the capacitor 60 through the diode 74 and boosts the capacitor voltage Vc.

  After performing the step-up operation in step S10 or S11, the process proceeds to step S13. Steps S13 to S16 are processes for the first booster circuit 31, and the same processes as in steps S1 to S6 are performed.

  The control unit 35 determines whether or not the capacitor voltage Vc is less than a predetermined voltage determination value V3 (S13). The voltage determination value V3 is set based on the self-inductance L3 of the coil 58, and the capacitor voltage Vc is set to a value that does not exceed a predetermined overexcitation voltage due to the counter electromotive force generated from the coil 58. When the determination in step S13 is No, the capacitor 60 is not boosted by the coil 58, and the process proceeds to return.

  When the determination in step S13 is Yes, the control unit 35 determines whether or not the first switching element 51 is out of order in step S14. The determination is the same as the processing in step S2, and is performed based on the command output from the control unit 35 to the first switching element 51 and the current value detected by the current detection unit 35C. If the determination in step S14 is Yes, the capacitor 60 is not boosted by the coil 58, a failure is output in step S16, and the process proceeds to return.

  If the determination in step S13 is No, in step S15, the control unit 35 alternately outputs an on / off command for the first switching element 51 to turn on / off the first switching element 51 to a predetermined duty ratio. To switch continuously. As a result, the back electromotive force generated in the coil 58 is supplied to the capacitor 60 through the diode 59 to boost the capacitor voltage Vc.

  In addition, the control unit 35 boosts the first, fifth, and sixth switching elements 51, 55, and 56 by switching them on and off when the fuel cut is performed regardless of the control in FIGS. It is better not to do. The control unit 35 may determine whether or not fuel cut control is performed based on a command from the fuel cut control unit 35F. When the fuel cut is being performed, the injector 3 is maintained in the closed state, and the voltage of the capacitor 60 does not decrease, so there is no need to boost the capacitor 60.

  FIG. 6 is an explanatory diagram when boosting is performed by the second booster circuit 32. As shown in FIG. 6, when the voltage of the capacitor 60 is applied to the solenoid 16 of the injector 3 as an overexcitation voltage at the initial opening of the injector 3, the capacitor voltage Vc becomes less than a predetermined overexcitation voltage. At this time, when an ON command is output to the fifth switching element 55, thereafter, an ON / OFF switching command is output from the control unit 35 to the fifth switching element 55. As a result, the current flowing through the first solenoid 21A of the first electric device 4 increases while the fifth switching element 55 is on and decreases while it is off. At this time, when the original state is on, the current flowing through the first solenoid 21A is maintained at the first current value or more depending on the length of the preset off period. When the current flowing through the first solenoid 21A changes, a counter electromotive force is generated in the first solenoid 21A. The counter electromotive force generated in the first solenoid 21A is rectified through the diode 71 and supplied to the capacitor 60 as a boosted current. As a result, the capacitor voltage Vc is boosted at each ON / OFF cycle of the fifth switching element 55 and recovered to a predetermined overexcitation voltage. On the other hand, when the original state is OFF, the current flowing through the first solenoid 21A is maintained below the second current value by the length of the preset OFF period.

  In the control apparatus 1 for an internal combustion engine configured as described above, when the capacitor voltage Vc becomes less than the voltage determination values V1 and V2, current is supplied to the solenoids 21A and 21B of the first or second electric devices 4 and 5. By changing the voltage, the capacitor voltage Vc can be boosted using the back electromotive force generated in the solenoid 21 of the first or second electric device 4 or 5. Therefore, the coil 58 can be downsized. Further, when the voltage of the capacitor voltage Vc is sufficiently increased by the solenoid 21 of the first or second electric device 4, 5, the coil 58 used only for boosting can be omitted. When the coil 58 is omitted, the first switching element 51 and the diode 59 may be omitted and the connection between one end of the capacitor 60 and the first terminal 41 may be cut off.

  In the step-up control, when the first and second electric devices 4 and 5 are on (when the plunger 22 is in the driving position), the solenoids 21A and 21B are turned on and off while passing a current equal to or higher than the first current value. Since the current is changed by switching, the operating state of the first or second electric device 4 or 5 does not change. On the other hand, when the first and second electric devices 4 and 5 are off (when the plunger 22 is in the initial position), the solenoids 21A and 21B are turned on and off while passing a current equal to or less than the second current value. Since the current is varied, the operating state of the first or second electric device 4 or 5 does not change. That is, the control device 1 can boost the capacitor 60 using the first and second electric devices 4 and 5 without affecting the operations of the first and second electric devices 4 and 5.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. In the said embodiment, although the example which provided the 2nd and 3rd voltage booster circuits 32 and 33 corresponding to the 1st and 2nd electric motors 4 and 5 was described, the 2nd and 3rd voltage booster circuits 32 and 33 are described. An arbitrary number can be provided corresponding to the number of electric devices 4 and 5. Moreover, although the example which provided the one drive circuit 34 corresponding to the one injector 3 was described in the said embodiment, the drive circuit 34 can provide arbitrary numbers corresponding to the number of the injectors 3. .

  In the above embodiment, one of the first to third booster circuits 31 to 33 is selected and boosted. However, a plurality of available booster circuits 31 to 33 are used simultaneously. Boosting may be performed.

  The electric devices 4 and 5 are not limited to electromagnetic valves such as an EGR valve and a purge valve, but are configured as an operating device of a hydraulic control device (hydraulic switching valve) or an operating device of a negative pressure control device (negative pressure switching valve). Also good. For example, when the electric device is configured as an operating device that drives a valve body that switches connection between each oil chamber of the variable valve mechanism and a hydraulic source in a hydraulic control device that switches hydraulic pressure supply to the variable valve mechanism and the like. Good. In addition, the electric device is a negative pressure control device that switches supply of negative pressure to a negative pressure actuator that drives a bypass valve (including a waste gate valve) of the turbocharger, and connects each negative pressure actuator to a negative pressure source. It is good to be comprised as an actuator which drives the valve body to switch.

1: Control device 2: Battery 3: Injector 4: First electric device 5: Second electric device 16: Solenoid 21: Solenoid 22: Plunger (actuator)
31: 1st voltage booster circuit 32: 2nd voltage booster circuit 33: 3rd voltage booster circuit 34: Drive circuit 35: Control part 35A: Voltage detection part 35B-35E: Current detection part 35F: Fuel cut control part 41-47: 1st To seventh terminals 51 to 56: first to sixth switching elements 58: coil 59: diode 60: capacitor 71: diode 75: diode

Claims (8)

Battery,
An electric device including a solenoid having one end connected to the battery and the other end grounded via a first switching element; and an operating body driven between the initial position and the driving position by the solenoid;
A first diode with an anode connected to the other end of the solenoid;
A capacitor having one end connected to the cathode of the first diode and the other end grounded;
An injector that is driven by power supplied from the capacitor or the battery;
A control unit for controlling the first switching element,
The control unit switches on and off the first switching element when the voltage of the capacitor is less than a predetermined value, and boosts the capacitor by a counter electromotive force generated in the solenoid. Engine control device.   The controller is configured to turn on the first switching element so that when the electric device is driven, a current equal to or higher than a first current value capable of holding the operating body in a driving position is supplied to the solenoid. 2. The control device for an internal combustion engine according to claim 1, wherein the control is switched off.   The control unit turns on the first switching element so that when the electric device is stopped, a current equal to or less than a second current value that can hold the operating body in an initial position is supplied to the solenoid; The control device for an internal combustion engine according to claim 1 or 2, characterized in that switching off is performed. The electric device, the first switching element, and the first diode cooperate to form a set,
4. The control device for an internal combustion engine according to claim 2, wherein a plurality of the sets are provided.   The control unit compares the voltage of the capacitor with a plurality of determination values set corresponding to each of the groups, and the first unit included in the group in which the voltage of the capacitor is less than the determination value. The control device for an internal combustion engine according to claim 4, wherein the switching element is switched on and off.   6. The control device for an internal combustion engine according to claim 5, wherein the determination value is set smaller as the self-inductance of the solenoid increases.   When the fuel cut control for maintaining the injector in a valve-closed state for a predetermined period is being executed, the controller switches the first switching element on and off even if the voltage of the capacitor becomes less than the determination value. The control apparatus for an internal combustion engine according to claim 5 or 6, wherein the control is not performed. A coil having one end connected to the battery and the other end grounded via a second switching element;
8. The device according to claim 1, further comprising a second diode having an anode connected to the other end of the coil and a cathode connected to one end of the capacitor. Control device for internal combustion engine.

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