Electromagnetic valve drive device

Abstract

In the present invention, an energization control unit performs: peak current driving, in which the peak current for moving a movable core in a valve-opening direction from a closed-valve state so as to cause the movable core to make contact with a stopper is delivered to a coil; and return current driving, in which, continuing from the peak current driving, a return current for pulling back the movable core in the valve-opening direction is delivered to the coil during a movement period caused by the rebounding of a valve part after the movable core moved in the valve-opening direction has made contact with the stopper. The return current in a second injection mode is greater than the return current in a first injection mode.

Description

Solenoid valve drive unit

[0001] The present invention relates to an electromagnetic valve drive device.

[0002] For example, Patent Document 1 discloses a fuel injection valve control device for specifying the valve opening timing when a large current is passed through the fuel injection valve to control it. The fuel injection valve control device disclosed in Patent Document 1 supplies a peak current, a pick current, and a hold current, each having different current values, to the coil of the fuel injection valve in order to inject fuel from the fuel injection valve.

[0003] Japanese Patent Application Laid-Open No. 2022-131759

[0004] For example, in a solenoid valve drive device such as the fuel injection valve control device disclosed in Patent Document 1, a peak current is supplied to the coil of the fuel injection valve to lift the movable core. The movable core, which is moved by the peak current supplied to the coil, lifts the valve portion. When the movable core, which is lifted by the peak current, collides with a stopper, the valve portion overshoots in the valve opening direction and is then returned by a spring in the valve closing direction, causing the valve portion to temporarily reciprocate. To suppress this reciprocating movement of the valve portion, the solenoid valve drive device supplies a pull-back current, such as a pick current, to the coil of the fuel injection valve to pull back the movable core, which has been separated from the stopper by the reciprocating movement of the valve portion. This pull-back current is smaller than the peak current to suppress power consumption. The solenoid valve drive device then supplies a holding current, such as a hold current, which is even weaker than the pull-back current, to the coil of the fuel injection valve to maintain the valve open state.

[0005] During the period when the holding current is supplied to the coil, the movable core and valve portion do not move, so the current-carrying period and the valve-closing timing have a linear relationship. In other words, the amount of change in the current-carrying period and the amount of change in the valve-closing timing are constant. On the other hand, during the period when the pull-back current is supplied to the coil, the movable core and valve portion move, so the current-carrying period and the valve-closing timing have a nonlinear relationship. For this reason, in an injection mode in which the coil is de-energized during the period when the pull-back current is supplied to the coil, it is difficult to accurately control the valve-closing timing by controlling the current-carrying period, resulting in a large error in the fuel injection amount of the fuel injector.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to suppress errors in the fuel injection amount of a fuel injection valve in an injection mode in which current to the coil is stopped during the period of movement due to the rebound of the valve portion after the movable core, which is moved in the valve opening direction, abuts against the stopper.

[0007] The present invention employs the following configuration as a means for solving the above problems.

[0008] A first aspect of the present invention is an electromagnetic valve drive device for controlling a fuel injection valve including a movable core that is pulled in a valve-opening direction by energizing a coil, a valve portion that is moved in the valve-opening direction as the movable core moves in the valve-opening direction, and a biasing portion that biases the valve portion in a valve-closing direction, the device including an energization control portion that controls energization of the coil, and a first injection mode that maintains energization of the coil even after the movable core moved in the valve-opening direction has stopped moving due to rebounding of the valve portion after contacting a stopper, and a second injection mode that stops energizing the coil during a period of movement due to rebounding of the valve portion after the movable core moved in the valve-opening direction has contacted a stopper. and a second injection mode in which the fuel injection valve is controlled based on the first injection mode, and when the valve portion is opened, the current supply control unit performs peak current drive in which a peak current is applied to the coil to move the movable core from a closed state in a valve opening direction and abut against a stopper, and subsequent to the peak current drive, performs pull-back current drive in which a pull-back current is applied to the coil to pull the movable core back in the valve opening direction during a movement period due to rebound of the valve portion after the movable core, being moved in the valve opening direction, abuts against the stopper, and the pull-back current in the second injection mode is larger than the pull-back current in the first injection mode.

[0009] In a fuel injection valve controlled by the electromagnetic valve drive device of the present invention, when the movable core is moved toward the stopper, the valve portion in the closed state is moved in the valve-opening direction together with the movable core. When the movable core collides with the stopper, the valve portion separates from the movable core due to inertial force and is then biased by the biasing portion to bounce back in the valve-closing direction. When the bouncing valve portion collides with the movable core, the movable core moves slightly in the valve-closing direction and then moves again toward the stopper. As a result, the valve portion moves back and forth in the valve-closing and valve-opening directions. In other words, the valve portion continues to move from the time the movable core abuts the stopper until the reciprocating movement converges (the period of movement due to the bouncing of the valve portion). In contrast, the electromagnetic valve drive device of the present invention can control the fuel injection valve in a first injection mode in which current is maintained to the coil even after the bouncing movement of the valve portion stops after the movable core, which is moving in the valve-opening direction, abuts the stopper. The electromagnetic valve drive device of the present invention can also control the fuel injection valve in a second injection mode in which current supply to the coil is stopped during a period of movement due to rebound of the valve portion after the movable core, moving in the valve opening direction, abuts against the stopper. Furthermore, the electromagnetic valve drive device of the present invention performs pull-back current drive, which supplies a pull-back current to the coil to pull the movable core back in the valve opening direction during a period of movement due to rebound of the valve portion after the movable core, moving in the valve opening direction, abuts against the stopper. The pull-back current in the second injection mode is greater than the pull-back current in the first injection mode. Therefore, in the second injection mode, a stronger force acts to suppress the movement of the valve portion than in the first injection mode, thereby suppressing the amount of movement of the valve portion. As a result, the relationship between the current supply period and the valve closing timing can be made closer to linear, thereby suppressing errors in the fuel injection amount of the fuel injection valve in the second injection mode.

[0010] 1 is a schematic diagram showing a schematic configuration of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 2 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 3 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 4 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 5 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 6 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention; FIG. 7 is a schematic diagram showing the operation of a fuel injection valve of a fuel injection valve controlled by a solenoid valve drive device according to one embodiment of the present invention;

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electromagnetic valve driving device according to the present invention will now be described with reference to the drawings.

[0012] 1 is a schematic diagram showing the general configuration of a fuel injection valve 100 controlled by a solenoid valve drive device 1 according to this embodiment. The solenoid valve drive device 1 according to this embodiment is a device that drives the fuel injection valve 100. Specifically, the solenoid valve drive device 1 according to this embodiment drives the fuel injection valve 100 (solenoid valve) that injects fuel into an internal combustion engine mounted on a vehicle.

[0013] The fuel injection valve 100 is an electromagnetic valve (solenoid valve) that injects fuel into an internal combustion engine, such as a gasoline engine or a diesel engine, mounted on a vehicle. FIG. 1 is a schematic configuration diagram of the fuel injection valve 100. As shown in FIG. 1, the fuel injection valve 100 includes a fixed core 101 (stopper), a valve seat 102, a solenoid coil 103 (coil), a needle 104, a valve body 105, a retainer 106, a lower stopper 107, a valve body biasing spring 108 (biasing portion), a movable core 109, and a movable core biasing spring 110. In this embodiment, the fixed core 101, the valve seat 102, and the solenoid coil 103 are fixed members. The needle 104, the valve body 105, the retainer 106, the lower stopper 107, the valve body biasing spring 108, the movable core 109, and the movable core biasing spring 110 are movable members.

[0014] The fixed core 101 is a cylindrical member that is fixed to a housing (not shown) of the fuel injection valve 100. The fixed core 101 is made of a magnetic material. The fixed core 101 functions as a stopper that restricts the movement of the movable core 109 that is attracted by the solenoid coil 103.

[0015] The valve seat 102 is fixed to the housing of the fuel injection valve 100. The valve seat 102 has an injection hole 102a. The injection hole 102a is a hole through which fuel is injected, and is closed when a valve body 105 is seated on the valve seat 102, and is opened when the valve body 105 is separated from the valve seat 102.

[0016] The solenoid coil 103 is formed by winding an electric wire in a circular shape. The solenoid coil 103 is arranged concentrically with the fixed core 101. The solenoid coil 103 is electrically connected to the electromagnetic valve drive device 1. When current is applied from the electromagnetic valve drive device 1, the solenoid coil 103 forms a magnetic path including the fixed core 101 and the movable core 109.

[0017] The needle 104 is a long rod member that extends along the central axis of the fixed core 101. The needle 104 is moved in the axial direction of the central axis of the fixed core 101 (the extension direction of the needle 104) by an attractive force generated by a magnetic path that includes the fixed core 101 and the movable core 109.

[0018] There are no particular limitations on the installation posture of the fuel injection valve 100. However, in the following description, the direction in which the movable core 109 moves due to the above-mentioned attractive force in the axial direction of the central axis of the fixed core 101 will be referred to as the valve-opening direction, and the direction opposite to the direction in which the movable core 109 moves due to the above-mentioned attractive force will be referred to as the valve-closing direction.

[0019] The valve element 105 is formed at the tip of the needle 104 in the valve closing direction. The valve element 105 closes the injection hole 102a by seating on the valve seat 102, and opens the injection hole 102a by moving away from the valve seat 102. The retainer 106 includes a guide member 106a and a flange 106b. The guide member 106a is a cylindrical member fixed to the tip of the needle 104 in the valve opening direction. The flange 106b is formed at the end of the guide member 106a in the valve opening direction so as to protrude in the radial direction of the needle 104. The end face of the flange 106b in the valve closing direction is an abutment surface with the movable core biasing spring 110. The end face of the flange 106b in the valve opening direction is an abutment surface with the valve element biasing spring 108.

[0020] The lower stopper 107 is a cylindrical member fixed to the needle 104 between the valve seat 102 and the guide member 106a. The lower stopper 107 has an end face in the valve opening direction that abuts against the movable core 109.

[0021] The valve body biasing spring 108 is a compression coil spring housed inside the fixed core 101 and is interposed between the inner wall surface of the housing and the flange 106b. The valve body biasing spring 108 biases the valve body 105 in the valve closing direction. That is, when the solenoid coil 103 is not energized, the biasing force of the valve body biasing spring 108 causes the valve body 105 to abut against the valve seat 102.

[0022] The movable core 109 is disposed between the guide member 106a and the lower stopper 107. The movable core 109 is a cylindrical member and is provided coaxially with the needle 104. A through-hole through which the needle 104 is inserted is formed in the center of the movable core 109, and the movable core 109 is movable along the direction in which the needle 104 extends. The end face of the movable core 109 in the valve opening direction is an abutment surface with the fixed core 101 and the movable core biasing spring 110. On the other hand, the end face of the movable core 109 in the valve closing direction is an abutment surface with the lower stopper 107. The movable core 109 is formed of a magnetic material.

[0023] The movable core biasing spring 110 is a compression coil spring interposed between the flange 106b and the movable core 109. The movable core biasing spring 110 biases the movable core 109 in the valve closing direction. That is, when the solenoid coil 103 is not energized, the movable core 109 is brought into contact with the lower stopper 107 by the biasing force of the movable core biasing spring 110.

[0024] In this embodiment, the needle 104, the valve body 105, and the retainer 106 are moved integrally by energizing the solenoid coil 103. The needle 104, the valve body 105, and the retainer 106, which are integrated together, form a valve portion 120. That is, in this embodiment, the valve portion 120, which has the valve body 105, is moved in the valve opening direction by energizing the solenoid coil 103.

[0025] The fuel injection valve 100 is controlled by the electromagnetic valve drive device 1 of this embodiment based on three injection modes: a first injection mode, a second injection mode, and a third injection mode, which will be described later.

[0026] The first injection mode is an injection mode in which current is maintained to the solenoid coil 103 even after the movable core 109, which is moved in the valve opening direction from the closed valve state (a state in which the valve body 105 abuts against the valve seat 102 and closes the injection hole 102a), abuts against the fixed core 101 and the movement of the valve portion 120 due to bouncing stops.

[0027] The first injection mode will be described in more detail with reference to Figures 2 to 6. Figures 2 to 6 are schematic diagrams showing the operation of the fuel injection valve 100. In the first injection mode, when the solenoid coil 103 is energized in the valve-closed state shown in Figure 1, the movable core 109 is moved in the valve-opening direction as shown in Figure 2. Thereafter, as shown in Figure 3, the movable core 109 abuts against the retainer 106 from the valve-closing direction. When the movable core 109 is further moved in the valve-opening direction, the valve portion 120 is moved in the valve-opening direction.

[0028] 4, when the movable core 109 collides with the fixed core 101, the movement of the movable core 109 is stopped. Meanwhile, the valve portion 120 continues to move in the valve opening direction due to inertial force, and overshoots to a position where the retainer 106 moves away from the movable core 109 in the valve opening direction.

[0029] The overshooting valve portion 120 rebounds in the valve closing direction due to the biasing force of the valve body biasing spring 108, and abuts against the movable core 109 from the valve opening direction, as shown in Figure 5. As shown in Figure 5, the impact force generated when the valve portion 120 collides with the movable core 109 causes the movable core 109 to move slightly away from the fixed core 101 in the valve closing direction.

[0030] The movable core 109, which is slightly separated from the fixed core 101 in the valve closing direction, is again drawn in the valve opening direction and abuts against the fixed core 101 because the solenoid coil 103 is energized. Thereafter, as shown in Figure 6, the movable core 109 abuts against the fixed core 101, and the valve portion 120 is stabilized in abutment against the movable core 109.

[0031] In this way, the valve portion 120 continues to move back and forth due to the bouncing until it reaches the stable state shown in Fig. 6. The number of times that the valve portion 120 repeats the bouncing back and forth movement may be one or more.

[0032] As shown in FIG. 6, the first injection mode is an injection mode in which the solenoid coil 103 remains energized for a certain period of time even after the valve portion 120 has stopped moving due to bouncing and stabilized, thereby keeping the valve portion 120 in an open state for a long period of time.

[0033] The second injection mode is an injection mode in which current supply to the solenoid coil 103 is stopped during the period of movement due to the rebound of the valve portion 120 after the movable core 109, which is moved from the valve closed state in the valve opening direction, abuts against the fixed core 101. In this second injection mode, the valve opening period is shorter than in the first injection mode, and the fuel injection amount is smaller than in the first injection mode.

[0034] In the second injection mode, the supply of current to the solenoid coil 103 is stopped during the reciprocating movement of the valve portion 120 due to rebounding as described in the first injection mode (for example, the states shown in Figures 4 and 5). Note that the second injection mode is entered if the supply of current to the solenoid coil 103 is stopped after the movable core 109 collides with the fixed core 101 from the valve closed state until the movement of the valve portion 120 due to rebounding stops.

[0035] The third injection mode is an injection mode in which the supply of current to the solenoid coil 103 is stopped before the movable core 109, which is moved from the valve closed state in the valve opening direction, abuts against the fixed core 101. The third injection mode has a shorter valve opening period than the first and second injection modes, and is the injection mode in which the fuel injection amount is the smallest among the three injection modes.

[0036] Next, the electromagnetic valve driving device 1 according to this embodiment will be described. Fig. 7 is a schematic diagram of the electromagnetic valve driving device 1 according to this embodiment. As shown in Fig. 7, the electromagnetic valve driving device 1 includes a driving device 2 and a control device 3.

[0037] The drive device 2 is a circuit that drives the fuel injection valve 100 by energizing a solenoid coil 103, which is a coil of the fuel injection valve 100. As shown in FIG. 7 , the drive device 2 includes a power supply device 2a and a switch 2b. The power supply device 2a includes at least one of a battery and a boost circuit. The battery is mounted on the vehicle. The boost circuit boosts the battery voltage, which is the output voltage of the battery, and outputs the boosted voltage.

[0038] The power supply device 2a can energize the solenoid coil 103 by outputting a battery voltage to the solenoid coil 103. The power supply device 2a can also energize the solenoid coil 103 by outputting a boosted voltage to the solenoid coil 103. The voltage output from the power supply device 2a to the solenoid coil 103 is controlled by a power supply control unit 3d (described later) of the control device 3. The power supply to the solenoid coil 103 is also controlled by a power supply control unit 3d (described later) of the control device 3.

[0039] The switch 2b is controlled to an on or off state by the control device 3. When the switch 2b is controlled to an on state, the voltage output from the power supply device 2a is supplied to the solenoid coil 103. This starts the flow of current to the solenoid coil 103. When the switch 2b is controlled to an off state, the supply of voltage from the power supply device 2a to the solenoid coil 103 is stopped. This stops the flow of current to the solenoid coil 103.

[0040] The control device 3 includes a voltage detection unit 3a and a control processing unit 3b. The voltage detection unit 3a detects the voltage (coil voltage) generated in the solenoid coil 103. For example, the coil voltage is the voltage across both ends of the solenoid coil 103. The voltage detection unit 3a outputs a signal indicating the value of the detected coil voltage (coil voltage value) to the control processing unit 3b.

[0041] The control processing unit 3b includes a valve closing detection unit 3c, a current supply control unit 3d, a current supply period correction unit 3e, and a memory unit 3f. The valve closing detection unit 3c detects the closure of the valve element 105. That is, the valve closing detection unit 3c detects the valve closing timing of the valve element 105 included in the fuel injection valve 100. The valve closing detection unit 3c reads the coil voltage value input from the voltage detection unit 3a and detects the closure of the fuel injection valve 100 based on the coil voltage value. The valve closing timing indicates the time at which the valve closing is detected, assuming that the time at which the solenoid coil 103 starts to be energized is set to 0. That is, the valve closing timing here is the elapsed time from the start of energization of the solenoid coil 103 to the detection of valve closure.

[0042] For example, the valve closure detection unit 3c detects the closure of the valve element 105 by detecting an inflection point of the coil voltage value. However, the valve closure detection unit 3c detects the closure of the valve element 105 by detecting an inflection point of a machining voltage value obtained by processing the coil voltage value. The machining voltage may be a differential value of the coil voltage value. Furthermore, high-frequency components may be removed from the coil voltage value used to detect the closure of the valve element 105 by a filter.

[0043] In this embodiment, the control device 3 is configured to include the valve-closed detection unit 3c. However, the control device 3 may be configured not to include the valve-closed detection unit 3c. For example, if the control device 3 does not include the current-carrying period correction unit 3e, the control device 3 does not need to include the valve-closed detection unit 3c.

[0044] The current supply control unit 3d controls the power supply device 2a. The current supply control unit 3d also controls the switch 2b to an on or off state. When the current supply control unit 3d controls the switch 2b to an on state, current is supplied to the solenoid coil 103. When the current supply control unit 3d controls the switch 2b to an off state, current is stopped from being supplied to the solenoid coil 103. The current supply control unit 3d controls the current supply period based on a program stored in the storage unit 3f and a post-stage corrected current supply period obtained by a current supply period correction unit 3e (described later).

[0045] Furthermore, the current supply control unit 3d controls the power supply unit 2a with the switch 2b in the on state, thereby controlling the current supplied to the solenoid coil 103. The current supply period correction unit 3e corrects the current supply period based on, for example, a correction amount map stored in the memory unit 3f. The current supply period correction unit 3e references the correction amount map and determines the correction amount based on, for example, the valve closing timing. The memory unit 3f stores, for example, the above-mentioned correction amount map. In addition to the correction amount map, the memory unit 3f also stores a drive control program for the fuel injection valve 100 and various calculated values.

[0046] Next, the operation of the energization control unit 3d will be described with reference to FIGS. 8 to 11. FIG. 8 is a diagram showing the change over time in the current supplied by the energization control unit 3d to the solenoid coil 103 in the first injection mode. FIG. 9 is a diagram showing the change over time in the position of the valve element 105 in the opening / closing direction in the first injection mode. FIG. 10 is a diagram showing the change over time in the current supplied by the energization control unit 3d to the solenoid coil 103 in the second injection mode. FIG. 11 is a diagram showing the change over time in the position of the valve element 105 in the opening / closing direction in the second injection mode. Note that in FIG. 10, the change over time in the current in the first injection mode is shown by a dashed line for comparison. Also, in FIG. 11, the change over time in the position of the valve element 105 in the first injection mode is shown by a dashed line for comparison.

[0047] 8, in the first injection mode, the current control unit 3d first performs peak current drive. In this peak current drive, the current control unit 3d supplies a peak current to the solenoid coil 103 to bring the movable core 109 into contact with the fixed core 101 from the valve-closed state.

[0048] In the first injection mode, the current supply control unit 3d performs the peak current drive followed by the pullback current drive. In the pullback current drive, the current supply control unit 3d supplies the solenoid coil 103 with a pullback current to pull the movable core 109 back in the valve opening direction during the movement period caused by the rebound of the valve portion 120 after the movable core 109 abuts against the fixed core 101 due to the peak current drive. The average value of this pullback current is lower than the maximum current of the peak current.

[0049] In the first injection mode, the current control unit 3d performs the pullback current drive and then the holding current drive. In this holding current drive, the current control unit 3d passes a holding current to the solenoid coil 103 to maintain the state in which the movable core 109 is in contact with the fixed core 101. The average value of this holding current is even lower than that of the pullback current.

[0050] As shown in FIG. 9 , in the first injection mode, the fuel injection valve 100 is driven by a peak current, a pullback current, and a holding current, so that the valve portion 120 is moved from a closed state in the valve opening direction, and the movable core 109 overshoots after colliding with the fixed core 101, and then moves back and forth in the opening and closing directions before being held in the open state.

[0051] As shown in Figure 10, in the second injection mode, the energization control unit 3d first performs peak current drive, as in the first injection mode. Furthermore, in the second injection mode, the energization control unit 3d performs peak current drive followed by pullback current drive. As shown in Figure 10, the pullback current in the second injection mode is larger than the pullback current in the first injection mode. Therefore, in the second injection mode, a larger current is supplied to the solenoid coil 103 during the pullback current drive period than in the first injection mode, and the movable core 109 is pulled more strongly in the valve opening direction than in the first injection mode. The average value of the pullback current in the second injection mode is also lower than the maximum peak current in the second injection mode.

[0052] In this embodiment, as shown in Figure 10, the peak current drive period in the second injection mode is the same as the peak current drive period in the first injection mode. On the other hand, the pullback current drive period in the second injection mode is shorter than the pullback current drive period in the first injection mode. This reduces power consumption during the pullback current drive period in the second injection mode.

[0053] Also, as shown in Figure 10, in the second injection mode, the current control unit 3d does not perform the holding current drive of the first injection mode, but stops the pullback current drive during the movement period and stops the current supply to the solenoid coil 103.

[0054] As shown in FIG. 11 , in the second injection mode, the fuel injection valve 100 is driven by a peak current and a pullback current, so that the valve portion 120 is moved from the closed state in the valve opening direction, and the movable core 109 overshoots after colliding with the fixed core 101, and then moves back and forth in the opening and closing direction, and from the middle of this reciprocating movement, moves in the valve closing direction beyond the range of reciprocating movement.

[0055] In this case, in the second injection mode, the pullback current is larger than that in the first injection mode, so the movable core 109 is pulled more strongly in the valve opening direction during the pullback current drive period. Therefore, as shown in Figure 11, in the second injection mode, the amount of reciprocating movement of the valve portion 120 during the pullback current drive period is smaller than that in the first injection mode.

[0056] In the third injection mode, the current supply control unit 3d performs peak current drive, but supplies current to the solenoid coil 103 so that the movable core 109 returns in the valve closing direction before colliding with the fixed core 101. As a result, in the third injection mode, the movable core 109 moves toward the valve closing direction without colliding with the fixed core 101.

[0057] The fuel injection valve 100 controlled by the electromagnetic valve drive device 1 of this embodiment as described above includes a movable core 109, a valve portion 120, and a valve element biasing spring 108. The movable core 109 is pulled in the valve opening direction when current is applied to the solenoid coil 103. The valve portion 120 is moved in the valve opening direction in conjunction with the movement of the movable core 109 in the valve opening direction. The valve element biasing spring 108 biases the valve portion 120 in the valve closing direction.

[0058] The electromagnetic valve drive device 1 of this embodiment, which controls such a fuel injection valve 100, includes an energization control unit 3d that controls energization of the solenoid coil 103. The electromagnetic valve drive device 1 of this embodiment can control the fuel injection valve 100 based on a first injection mode and a second injection mode. The first injection mode is an injection mode in which energization to the solenoid coil 103 is maintained even after the movable core 109, which is moved in the valve opening direction, abuts against the fixed core 101 and then stops moving due to rebound of the valve portion 120. The second injection mode is an injection mode in which energization to the solenoid coil 103 is stopped during the period in which the movable core 109, which is moved in the valve opening direction, abuts against the fixed core 101 and then stops moving due to rebound of the valve portion 120.

[0059] Furthermore, when opening the valve portion 120, the energization control unit 3d in the electromagnetic valve drive device 1 of this embodiment performs peak current drive and pullback current drive. In peak current drive, the energization control unit 3d supplies a peak current to the solenoid coil 103 to move the movable core 109 in the valve opening direction from the valve closed state and bring it into contact with the fixed core 101. In pullback current drive, the energization control unit 3d supplies a pullback current to the solenoid coil 103 to pull the movable core 109 back in the valve opening direction during a period of movement due to rebound of the valve portion 120 after the movable core 109, which is being moved in the valve opening direction, comes into contact with the fixed core 101. Furthermore, in the electromagnetic valve drive device 1 of this embodiment, the pullback current in the second injection mode is greater than the pullback current in the first injection mode.

[0060] In the fuel injection valve 100 controlled by the electromagnetic valve drive device 1 of this embodiment, the valve portion 120 in the valve-closed state is moved in the valve-opening direction together with the movable core 109 as the movable core 109 moves toward the fixed core 101. When the movable core 109 collides with the fixed core 101, the valve portion 120 is separated from the movable core 109 by inertial force and then is urged by the valve element urging spring 108 to bounce back in the valve-closing direction. When the rebounded valve portion 120 collides with the movable core 109, the movable core 109 moves slightly in the valve-closing direction and then moves again toward the fixed core 101. As a result, the valve portion 120 moves back and forth between the valve-closing direction and the valve-opening direction. In other words, the valve portion 120 continues to move from the time the movable core 109 abuts against the fixed core 101 until the reciprocating movement converges (the movement period due to the rebound of the valve portion 120).

[0061] In contrast, the electromagnetic valve drive device 1 of this embodiment can control the fuel injection valve 100 in a first injection mode in which current is maintained to the solenoid coil 103 even after the movable core 109, being moved in the valve opening direction, stops moving due to rebound of the valve portion 120 after it abuts against the fixed core 101. Furthermore, the electromagnetic valve drive device 1 of the present invention can control the fuel injection valve 100 in a second injection mode in which current is stopped to the solenoid coil 103 during the period in which the movable core 109, being moved in the valve opening direction, stops moving due to rebound of the valve portion 120 after it abuts against the fixed core 101.

[0062] Furthermore, the solenoid valve drive device 1 of this embodiment performs pull-back current drive by passing a pull-back current through the solenoid coil 103 to pull the movable core 109 back in the valve-opening direction during a period of movement due to rebound of the valve portion 120 after the movable core 109, which is being moved in the valve-opening direction, abuts against the fixed core 101. The pull-back current in the second injection mode is greater than the pull-back current in the first injection mode. Therefore, in the second injection mode, a stronger force acts to suppress the movement of the valve portion 120 than in the first injection mode, thereby suppressing the amount of movement of the valve portion 120. As a result, the relationship between the energization period and the valve-closing timing can be made closer to linear, thereby suppressing errors in the fuel injection amount of the fuel injection valve 100 in the second injection mode.

[0063] In addition, in the solenoid valve drive device 1 of this embodiment, in the first injection mode, the current control unit 3d performs a holding current drive, following the pullback current drive, in which a holding current is passed through the solenoid coil 103 to maintain the movable core 109 in contact with the fixed core 101.

[0064] According to the electromagnetic valve drive device 1 of this embodiment, in the first injection mode, a holding current flows to the solenoid coil 103. Therefore, it is possible to maintain the valve open state for a long time in the first injection mode.

[0065] Furthermore, in the electromagnetic valve drive device 1 of this embodiment, the holding current is smaller than the pullback current in the first injection mode. According to the electromagnetic valve drive device 1 of this embodiment, the holding current is smaller than the pullback current in the first injection mode and the pullback current in the second injection mode. Therefore, power consumption during the holding current drive period can be reduced.

[0066] In addition, in the solenoid valve drive device 1 of this embodiment, in the second injection mode, the current control unit 3d does not perform holding current drive, but stops the pullback current drive during the movement period and stops the current supply to the solenoid coil 103.

[0067] According to the electromagnetic valve drive device 1 of this embodiment, in the second injection mode, no holding current flows to the solenoid coil 103, and only in the first injection mode, a holding current flows to the solenoid coil 103. Therefore, the energization period in the second injection mode is reliably shorter than in the first injection mode, and a smaller flow rate of fuel can be injected from the fuel injection valve 100.

[0068] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0069] For example, in the above embodiment, the configuration has been described in which the supply of current to the solenoid coil 103 is stopped after the pullback current drive in the second injection mode. However, the present invention is not limited to this. For example, in the second injection mode, a small current may be passed through the solenoid coil 103 after the pullback current drive.

[0070] The above embodiment can also be described as follows, for example:

[0071] (Supplementary Note 1) An electromagnetic valve drive device for controlling a fuel injection valve including a movable core that is pulled in a valve opening direction by energizing a coil, a valve portion that is moved in the valve opening direction as the movable core moves in the valve opening direction, and a biasing portion that biases the valve portion in a valve closing direction, the device comprising an energization control portion that controls energization of the coil, and is capable of controlling the fuel injection valve based on: a first injection mode in which energization to the coil is maintained even after the movable core moved in the valve opening direction has stopped moving due to rebound after contacting a stopper, and a second injection mode in which energization to the coil is stopped during a period in which the movable core moved in the valve opening direction has stopped moving due to rebound after contacting the stopper, and when opening the valve portion, the energization control portion performs peak current drive that flows a peak current through the coil to move the movable core from a valve closed state in the valve opening direction so that the movable core contacts a stopper; the peak current driving is followed by a pull-back current driving for passing a pull-back current through the coil to pull the movable core back in the valve-opening direction during a movement period caused by rebound of the valve portion after the movable core, being moved in the valve-opening direction, comes into contact with the stopper, and the pull-back current in the second injection mode is greater than the pull-back current in the first injection mode.

[0072] (Supplementary Note 2) In the solenoid valve drive device according to Supplementary Note 1, in the first injection mode, the current supply control unit performs holding current drive, following the pull-back current drive, to supply a holding current to the coil to maintain a state in which the movable core abuts against the stopper.

[0073] (Supplementary Note 3) The electromagnetic valve drive device according to Supplementary Note 2, wherein the holding current is smaller than the pullback current in the first injection mode.

[0074] (Supplementary Note 4) The solenoid valve drive device according to Supplementary Note 2 or 3, wherein in the second injection mode, the energization control unit stops the pullback current drive during the movement period to stop energization of the coil without performing the holding current drive.

[0075] REFERENCE SIGNS LIST 1 Electromagnetic valve drive device 2 Drive device 3 Control device 3a Voltage detection unit 3b Control processing unit 3c Valve closing detection unit 3d Current supply control unit 3e Current supply period correction unit 3f Memory unit 100 Fuel injection valve 101 Fixed core (stopper) 102 Valve seat 103 Solenoid coil (coil) 104 Needle 105 Valve body 106 Retainer 107 Lower stopper 108 Valve body biasing spring (biasing unit) 109 Movable core 110 Movable core biasing spring 120 Valve unit

Claims

1. A solenoid valve drive device for controlling a fuel injection valve including a movable core that is pulled in a valve opening direction by energizing a coil, a valve portion that is moved in the valve opening direction as the movable core moves in the valve opening direction, and a biasing portion that biases the valve portion in a valve closing direction, the device further comprising an energization control portion for controlling energization of the coil, and is capable of controlling the fuel injection valve based on a first injection mode in which energization of the coil is maintained even after the movable core moved in the valve opening direction stops moving due to bouncing after it abuts against a stopper, and a second injection mode in which energization of the coil is stopped during a period of movement of the valve portion due to bouncing after the movable core moved in the valve opening direction abuts against a stopper, and when the valve portion is opened, the energization control portion is configured to: the peak current driving is followed by a pull-back current driving for flowing a pull-back current through the coil to pull the movable core back in the valve-opening direction during a movement period caused by rebound of the valve portion after the movable core, being moved in the valve-opening direction, comes into contact with the stopper, and the pull-back current in the second injection mode is larger than the pull-back current in the first injection mode.

2. The solenoid valve drive device according to claim 1, wherein in the first injection mode, the current supply control unit performs a holding current drive, following the pull-back current drive, in which a holding current is passed through the coil to maintain the movable core in contact with the stopper.

3. The solenoid valve drive device according to claim 2, wherein the holding current is smaller than the pullback current in the first injection mode.

4. The solenoid valve drive device according to claim 2 or 3, wherein in the second injection mode, the current control unit stops the pullback current drive during the movement period and stops the current supply to the coil without performing the holding current drive.

Images