Solenoid valve drive unit

Abstract

Provided is an electromagnetic valve drive device that controls a period at which a solenoid coil provided in a fuel injection valve is energized, and that causes the fuel injection valve to inject fuel a plurality of times in one combustion cycle of an internal combustion engine, the electromagnetic valve drive device comprising: a storage unit that stores a correction amount map showing a relationship between an energization idle period from a complete time of a previous energization period that is an energization period for precedent fuel injection in one combustion cycle to a start time of a subsequent energization period that is an energization period for next fuel injection and a correction amount with respect to the subsequent energization period; an energization period correction unit that calculates a correction amount from a command value in the energization idle period on the basis of the correction amount map, and that corrects the subsequent energization period on the basis of the calculated correction amount; and an energization control unit that energizes the solenoid coil on the basis of a subsequent correction energization period that is the subsequent energization period corrected by the energization period correction unit.

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses a fuel injection control device. This fuel injection control device is applied to a fuel injection system capable of performing multi-stage injection, injecting fuel multiple times within a combustion cycle. The fuel injection control device disclosed in Patent Document 1 calculates the magnetic flux remaining in the fuel injection valve and corrects the injection mode of the rear-stage injection based on the calculated residual magnetic flux. Furthermore, Patent Document 2 discloses a fuel injection control device that estimates the residual voltage of the solenoid coil of the fuel injection valve and corrects the valve opening period based on the estimated residual voltage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-96275 [Patent Document 2] Japanese Patent Application Publication No. 2017-96118 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the fuel injection control device disclosed in Patent Document 1 requires a calculation to calculate the residual magnetic flux. Furthermore, the fuel injection device disclosed in Patent Document 2 requires a calculation to estimate the residual voltage. A large number of combustion cycles occur in an internal combustion engine in a short period of time. Therefore, performing a large number of calculations within a combustion cycle, as in the fuel injection control devices disclosed in Patent Documents 1 and 2, significantly increases the calculation processing load on the fuel injection control device.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to suppress an increase in the load of calculation processing caused by making corrections related to fuel injection in an electromagnetic valve drive device that causes a fuel injection valve to inject fuel multiple times during one combustion cycle of an internal combustion engine. [Means for solving the problem]

[0006] The present invention employs the following configuration as a means for solving the above problems.

[0007] A first aspect of the present invention is an electromagnetic valve drive device that controls a period of time during which a current is applied to a solenoid coil provided in a fuel injection valve, and causes the fuel injection valve to inject fuel multiple times during one combustion cycle of an internal combustion engine, and is configured to include: a memory unit that stores a correction amount map showing the relationship between a current-off period from the end time of a first-stage current application period, which is the current application period for a previous fuel injection during the one combustion cycle, to the start time of a second-stage current application period, which is the current application period for a next fuel injection, and a correction amount for the second-stage current application period; a current application period correction unit that calculates the correction amount from a command value for the current-off period based on the correction amount map, and corrects the second-stage current application period based on the calculated correction amount; and a current application control unit that applies current to the solenoid coil based on the second-stage corrected current application period, which is the second-stage current application period corrected by the current application period correction unit.

[0008] A second aspect of the present invention is configured in the first aspect, wherein the fuel injection valve comprises a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, the memory unit stores, as the correction amount map, a maximum drive correction amount map that indicates the relationship between the energization pause period and the correction amount when maximum drive is performed in which the movable core abuts against the fixed core in a single fuel injection, and the energization period correction unit determines the correction amount from a command value for the energization pause period based on the maximum drive correction amount map when the fuel injection based on the front-stage energization period and the fuel injection based on the rear-stage energization period are the maximum drive.

[0009] A third aspect of the present invention is configured such that, in the first or second aspect, the fuel injection valve comprises a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, the memory unit stores, as the correction amount map, a mid-drive correction amount map that indicates a relationship between the energization halt period and the correction amount in the case of mid-drive in which the movable core is not moved until it abuts the fixed core in a single fuel injection, and the energization period correction unit determines the correction amount from a command value for the energization halt period based on the mid-drive correction amount map when the fuel injection based on the front-stage energization period and the fuel injection based on the rear-stage energization period are mid-drive.

[0010] A fourth aspect of the present invention is the fuel injection valve of the first aspect, wherein the fuel injection valve comprises a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, and the storage unit stores, as the correction amount map, a maximum drive correction amount map that indicates a relationship between the energization halt period and the correction amount when maximum drive is performed in which the movable core abuts against the fixed core in one fuel injection, and a relationship between the energization halt period and the correction amount when intermediate drive is performed in which the movable core is not moved until abutting against the fixed core in one fuel injection. and a mid-drive correction amount map indicating the maximum drive or the mid-drive, and the current supply period correction unit determines whether the fuel injection is the maximum drive or the mid-drive, and if the fuel injection based on the front-stage current supply period and the fuel injection based on the rear-stage current supply period are the maximum drive, calculates the correction amount from a command value for the current supply halt period based on the maximum drive correction amount map, and if the fuel injection based on the front-stage current supply period and the fuel injection based on the rear-stage current supply period are the mid-drive, calculates the correction amount from the command value for the current supply halt period based on the mid-drive correction amount map.

[0011] A fifth aspect of the present invention is configured such that, in the third or fourth aspect, the mid-drive correction amount map indicates a relationship between the power supply halt period and the correction amount depending on the previous-stage power supply period, and the power supply period correction unit determines the correction amount from a command value for the previous-stage power supply period and a command value for the power supply halt period.

[0012] A sixth aspect of the present invention, in any one of the first to fifth aspects, further comprises a valve closure detection unit that detects the closure of the fuel injection valve, and the current conduction period correction unit calculates a difference between an estimated valve closure time obtained from the post-correction current conduction period and a valve closure detection time by the valve closure detection unit, and further corrects the post-correction current conduction period after calculation of the difference.

[0013] A seventh aspect of the present invention employs a configuration in any one of the first to sixth aspects, in which the power supply suspension period and the correction amount are related to each other so that the valve closing timing in the next fuel injection is advanced in response to an advancement of the valve opening timing in the next fuel injection caused by at least one of a residual magnetic force and an increase in the effective boost voltage due to the influence of the previous fuel injection. [Effects of the Invention]

[0014] According to the present invention, a storage unit stores a correction amount map indicating a relationship between a power supply halt period and a correction amount for a rear-stage power supply period. Furthermore, the correction amount for the rear-stage power supply period is calculated based on the correction amount map from a command value for the power supply halt period. Therefore, the present invention reduces the load of calculation processing compared to a case where the correction amount for the rear-stage power supply period is calculated without using the correction amount map. Therefore, according to the present invention, in a solenoid valve drive device that causes a fuel injection valve to inject fuel multiple times during one combustion cycle of an internal combustion engine, it is possible to suppress an increase in the load of calculation processing caused by performing a correction related to fuel injection. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a general configuration of a fuel injection valve controlled by an electromagnetic valve drive device according to an embodiment of the present invention; [Figure 2] 1 is a schematic configuration diagram of an electromagnetic valve drive device according to an embodiment of the present invention; [Figure 3] FIG. 10 is a conceptual diagram of a full-lift correction amount map. [Figure 4] FIG. 10 is a schematic diagram showing a state in which a post-stage energization period is corrected and shortened using a full-lift correction amount map. [Figure 5] FIG. 10 is a conceptual diagram of a half-lift correction amount map. [Figure 6] FIG. 10 is a schematic diagram showing a state in which a rear-stage energization period is corrected and shortened using a half-lift correction amount map. [Figure 7] 4 is a flowchart illustrating the operation of the electromagnetic valve drive device according to the embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram showing a state in which fuel injection is performed three or more times in one fuel cycle in a modified example of the electromagnetic valve drive device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a solenoid valve driving device according to the present invention will now be described with reference to the drawings.

[0017] 1 is a schematic diagram showing the general configuration of a fuel injection valve 100 controlled by a solenoid valve driving device 1 of this embodiment. The solenoid valve driving device 1 of this embodiment is a driving device that drives the fuel injection valve 100. Specifically, the solenoid valve driving 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.

[0018] 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, a valve seat 102, a solenoid coil 103, a needle 104, a valve body 105, a retainer 106, a lower stopper 107, a valve body biasing spring 108, 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.

[0019] The fixed core 101 is a cylindrical member and is fixed to a housing (not shown) of the fuel injection valve 100. The fixed core 101 is made of a magnetic material. 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 element 105 is seated on the valve seat 102 and is opened when the valve element 105 is separated from the valve seat 102.

[0020] 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 driving device 1. When current is applied from the electromagnetic valve driving device 1, the solenoid coil 103 forms a magnetic path including the fixed core 101 and the movable core 109.

[0021] 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.

[0022] There is no particular limitation 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 "upward," 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 "downward."

[0023] The valve element 105 is formed at the lower tip of the needle 104. The valve element 105 closes the injection hole 102a when seated on the valve seat 102, and opens the injection hole 102a when separated 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 upper tip of the needle 104. The flange 106b is formed at the upper end of the guide member 106a so as to protrude in the radial direction of the needle 104. The lower end face of the flange 106b is an abutment surface with the movable core biasing spring 110. The upper end face of the flange 106b is an abutment surface with the valve element biasing spring 108.

[0024] The lower stopper 107 is a cylindrical member fixed to the needle 104 between the valve seat 102 and the guide member 106a. The upper end face of the lower stopper 107 is the contact face with the movable core 109.

[0025] The valve element 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 element biasing spring 108 biases the valve element 105 downward. That is, when the solenoid coil 103 is not energized, the biasing force of the valve element biasing spring 108 causes the valve element 105 to abut against the valve seat 102.

[0026] 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 upper end face of the movable core 109 is an abutment surface with the fixed core 101 and the movable core biasing spring 110. On the other hand, the lower end face of the movable core 109 is an abutment surface with the lower stopper 107. The movable core 109 is formed of a magnetic material.

[0027] 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 downward. That is, when power is not supplied to the solenoid coil 103, the movable core 109 is brought into contact with the lower stopper 107 by the biasing force of the movable core biasing spring 110.

[0028] Next, the electromagnetic valve driving device 1 according to this embodiment will be described. Fig. 2 is a schematic configuration diagram of the electromagnetic valve driving device 1 according to this embodiment. As shown in Fig. 2, the electromagnetic valve driving device 1 includes a driving device 2 and a control device 3.

[0029] As shown in Fig. 2, 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 a battery voltage Vb, which is the output voltage of the battery, and outputs the boosted voltage Vs.

[0030] The power supply device 2a may energize the solenoid coil 103 by outputting a battery voltage Vb to the solenoid coil 103. The power supply device 2a may energize the solenoid coil 103 by outputting a boosted voltage Vs to the solenoid coil 103. The voltage output from the power supply device 2a to the solenoid coil 103 is controlled by the control device 3. In addition, the energization of the solenoid coil 103 is controlled by the control device 3.

[0031] 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.

[0032] The control device 3 includes a voltage detection unit 3a and a control processing unit 3b. The voltage detection unit 3a detects a voltage Vc generated in the solenoid coil 103. For example, the voltage Vc is the voltage across both ends of the solenoid coil 103. The voltage detection unit 3a outputs the detected voltage Vc to the control processing unit 3b.

[0033] The control processing unit 3b includes a valve closure detection unit 3c, a current control unit 3d, a current application period correction unit 3e, and a memory unit 3f. The valve closure detection unit 3c detects the closure of the valve element 105. For example, the valve closure detection unit 3c detects the closure of the fuel injection valve 100 based on the voltage Vc detected by the voltage detection unit 3a. As an example, the valve closure detection unit 3c detects the closure of the valve element 105 by detecting an inflection point of the voltage Vc detected by the voltage detection unit 3a. However, the valve closure detection unit 3c detects the closure of the valve element 105 by detecting an inflection point of a voltage processed by a predetermined process from the voltage Vc detected by the voltage detection unit 3a. The processed voltage may be a differential value of the voltage Vc. Furthermore, high-frequency components may be removed from the voltage Vc used to detect the closure of the valve element 105 by a filter.

[0034] The current supply control unit 3d controls the power supply device 2a. The current supply control unit 3d 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 supply to the solenoid coil 103 is stopped. The current supply control unit 3d controls the current supply period Ti based on a program stored in the memory unit 3f and a post-stage corrected current supply period calculated by a current supply period correction unit 3e (described later). The current supply period Ti indicates the period during which current is supplied to the solenoid coil 103, and is the time from when current supply to the solenoid coil 103 starts at a current supply start time T1 to when the current supply stops at a current supply stop time T2. The control device 3 controls the current supply period Ti to control the amount of fuel injected from the fuel injection valve 100 (hereinafter referred to as the fuel injection amount).

[0035] The electromagnetic valve drive device 1 of this embodiment performs multi-stage injection control, which causes the fuel injection valve 100 to inject fuel multiple times in one combustion cycle of an internal combustion engine (for example, a cycle in which the intake stroke, compression stroke, combustion stroke, and exhaust stroke are performed once each). In this embodiment, an example will be described in which the fuel injection valve 100 performs two fuel injections in one combustion cycle. Of the two fuel injections performed in one combustion cycle, the earlier fuel injection is called a front-stage injection, and the next fuel injection is called a rear-stage injection.

[0036] The fuel injection valve 100 injects fuel for each current conduction period Ti. That is, in this embodiment, two current conduction periods Ti are provided in one combustion cycle. The previous current conduction period Ti is a current conduction period for pre-stage injection. The previous current conduction period Ti is referred to as a pre-stage current conduction period Tia. The next current conduction period Ti is a current conduction period for post-stage injection. The next current conduction period Ti is referred to as a post-stage current conduction period Tib.

[0037] Between the first-stage current supply period Tia and the second-stage current supply period Tib, there is provided a current supply halt period Tp during which current supply to the solenoid coil 103 is halted. This current supply halt period Tp is the period from current supply halt time T2 of the first-stage current supply period Tia to current supply start time T1 of the second-stage current supply period Tib.

[0038] The current conduction period correction unit 3e corrects the latter-stage current conduction period Tib based on a correction amount map M, which will be described later and is stored in the storage unit 3f. The current conduction period correction unit 3e references the correction amount map M and determines the correction amount for the latter-stage current conduction period Tib based on a command value for the current conduction halt period Tp. If the command value for the current conduction halt period Tp is stored in a program in advance, it may be obtained directly from the program. Alternatively, the command value for the current conduction halt period Tp may be calculated based on the time from the current conduction stop time T2 of the former-stage current conduction period Tia to the current conduction start time T1 of the latter-stage current conduction period Tib.

[0039] Furthermore, the current conduction period correction unit 3e corrects the post-stage current conduction period Tib based on the calculated correction amount. The corrected post-stage current conduction period Tib (hereinafter referred to as the post-stage corrected current conduction period Tib) is input to the current conduction control unit 3d. The current conduction control unit 3d applies current for post-stage injection to the solenoid coil 103 based on the post-stage corrected current conduction period Tib.

[0040] Here, when multi-stage injection control is performed, the influence of the residual magnetic force after the pre-stage injection and the increase in the effective boost voltage causes the start timing of the post-stage injection to be earlier than the design value. Residual magnetic force is magnetic force that remains in the fuel injection valve 100 due to the influence of the pre-stage injection. The magnetic force generated in the fuel injection valve 100 by the pre-stage injection tends to zero after the pre-stage injection, but does not immediately reach zero. For this reason, magnetic force may remain in the fuel injection valve 100 at the start time T1 of the post-stage current period Tib. The magnetic force that remains in the fuel injection valve 100 at the start time T1 of the post-stage current period Tib is the residual magnetic force. Due to the influence of this residual magnetic force, the attractive force of the movable core 109 during the post-stage injection becomes higher than the design value. This causes the start timing of the post-stage injection to be earlier.

[0041] The effective boost voltage is the voltage applied to the solenoid coil 103 at the current start time T1 of the current supply period Ti. When the pre-stage injection is completed, the voltage remaining in the solenoid coil 103 drops to the clamp voltage once and then returns to zero over time. For this reason, the voltage of the solenoid coil 103 may not have returned to zero at the current supply start time T1 of the post-stage current supply period Tib. Due to the influence of this residual voltage, the boost voltage applied to the solenoid coil 103 at the current supply start time T1 of the post-stage current supply period Tib becomes higher than the design value. In other words, the effective boost voltage increases. This advances the start timing of the post-stage injection.

[0042] The correction amount map M is a map showing the relationship between the power supply cessation period Tp and the correction amount for the rear-stage power supply period Tib. This correction amount is set to advance the end timing of the rear-stage injection by the amount of the advancement of the start timing of the rear-stage injection due to the increase in the residual magnetic force and the effective boost voltage described above. Specifically, when the start timing of the rear-stage injection is advanced by the time Ta from the design value, the correction amount is set to advance the power supply stop time T2 of the rear-stage power supply period Tib by the time Ta so that the rear-stage power supply period Tib is shortened by the time Ta. This correction amount is obtained in advance by experiment or simulation.

[0043] As described above, the influence of the residual magnetic force and the influence of the increase in the effective boost voltage decrease over time. In other words, the longer the power supply suspension period Tp, the less the advancement of the start timing of the rear-stage injection. For this reason, the correction amount map M associates the power supply suspension period Tp with the correction amount so that the longer the power supply suspension period Tp, the smaller the correction amount.

[0044] In this embodiment, a full-lift correction amount map Ma and a half-lift correction amount map Mb are stored in the storage unit 3f as the correction amount maps M. The full-lift correction amount map Ma (maximum drive correction amount map) is the correction amount map M used when the fuel injection in one combustion cycle is full-lift injection. That is, in this embodiment, the full-lift correction amount map Ma is referenced when the front-stage injection and the rear-stage injection are full-lift injections.

[0045] Full lift injection is a fuel injection in which the movable core 109 of the fuel injection valve 100 is moved until it contacts the fixed core 101 in one fuel injection. That is, in full lift injection, the movable core 109 is moved to the maximum position within its movable range. In other words, the full lift correction amount map Ma used in such full lift injection indicates the relationship between the correction amounts for the power supply halt period Tp and the post-stage power supply period Tib when the movable core 109 is driven to the maximum extent that it contacts the fixed core 101 in one fuel injection.

[0046] FIG. 3 is a conceptual diagram of the full-lift correction amount map Ma. As shown in this figure, the full-lift correction amount map Ma is a map showing the relationship between the power supply halt period Tp and the correction amount for the post-power supply period Tib. Note that in FIG. 3, the correction amount for the post-power supply period Tib is abbreviated as "XX." For example, as shown in FIG. 3, in the full-lift correction amount map Ma, the power supply halt period Tp is divided into regular periods Tp1 to Tpn. Furthermore, in the full-lift correction amount map Ma, the correction amount for the post-power supply period Tib is set for each of Tp1 to Tpn.

[0047] FIG. 4 is a schematic diagram showing the state in which the rear-stage current conduction period Tib is corrected and shortened using the full-lift correction amount map Ma. In FIG. 4, the upper part shows the change over time in the voltage applied to the solenoid coil 103, and the lower part shows the change over time in the amount of movement of the movable core 109 from the valve-closed state. As shown in FIG. 4, when the rear-stage current conduction period Tib is corrected and shortened using the full-lift correction amount map Ma, the start time of the movable core 109 for rear-stage injection is advanced by the time Ta, and the return time of the movable core 109 to the valve-closed position is also advanced by the time Ta. As a result, the difference between the design value of the fuel injection amount for rear-stage injection can be reduced.

[0048] The half-lift correction amount map Mb (mid-drive correction amount map) is the correction amount map M used when the fuel injection in one combustion cycle is half-lift injection. That is, in this embodiment, when the front-stage injection and the rear-stage injection are half-lift injections, the half-lift correction amount map Mb is referenced.

[0049] Half-lift injection is a type of fuel injection in which the movable core 109 of the fuel injection valve 100 is not moved until it abuts against the fixed core 101 during one fuel injection. In other words, in half-lift injection, the movable core 109 is not moved to the maximum position within its movable range. In this type of half-lift injection, the position of the movable core 109 changes over time in a parabolic curve, so it is also called ballistic injection. Note that in half-lift injection, the maximum displacement position of the movable core 109 is not limited to half the maximum position of the movable core 109 in full-lift injection.

[0050] That is, the half-lift correction amount map Mb used in such half-lift injection shows the relationship between the power supply halt period Tp and the correction amount for the latter-stage power supply period Tib when performing midway driving in which a single fuel injection does not move the movable core 109 until it abuts against the fixed core 101. Furthermore, the half-lift correction amount map Mb associates the power supply halt period Tp with the correction amount according to the value of the former-stage power supply period Tia.

[0051] FIG. 5 is a conceptual diagram of the half-lift correction amount map Mb. As shown in this figure, the half-lift correction amount map Mb is a map that shows the relationship between the correction amounts for the power supply halt period Tp and the rear-stage power supply period Tib according to the value of the front-stage power supply period Tia. Note that in FIG. 5, the correction amount for the rear-stage power supply period Tib is abbreviated as "XX." For example, as shown in FIG. 5, in the half-lift correction amount map Mb, the power supply halt period Tp is divided into regular periods Tp1 to Tpn. Furthermore, in the half-lift correction amount map Mb, the correction amount for the rear-stage power supply period Tib is set for each of Tp1 to Tpn.

[0052] Furthermore, in the half-lift correction amount map Mb, the pre-stage current supply period Tia is divided into Tia1 to Tian at regular intervals. For each of these Tia1 to Tian, ​​correction amounts for the current supply halt period Tp and the post-current supply period Tib are set. In other words, in the half-lift correction amount map Mb, the correction amount for the post-current supply period Tib can be obtained using the pre-stage current supply period Tia and the current supply halt period Tp as parameters.

[0053] FIG. 6 is a schematic diagram showing the state in which the rear-stage current application period Tib is corrected and shortened using the half-lift correction amount map Mb. In FIG. 6, the upper part shows the change over time in the voltage applied to the solenoid coil 103, and the lower part shows the change over time in the amount of movement of the movable core 109 from the valve-closed state. As shown in FIG. 6, when the rear-stage current application period Tib is corrected and shortened using the half-lift correction amount map Mb, the start time of the movable core 109 for rear-stage injection is advanced by the time Ta, and the return time of the movable core 109 to the valve-closed position is also advanced by the time Ta. As a result, the difference between the design value of the fuel injection amount for rear-stage injection can be reduced.

[0054] When multi-stage injection control is performed with half-lift injection, the residual magnetic force of the fuel injection valve 100 varies greatly depending on the value of the front-stage current supply period Tia. Therefore, by relating the correction amounts for the current supply cessation period Tp and the rear-stage current supply period Tib to the value of the front-stage current supply period Tia in the half-lift correction amount map Mb, it is possible to more reliably reduce the difference between the design value of the fuel injection amount for rear-stage injection.

[0055] The storage unit 3f stores the above-mentioned correction amount map M. In this embodiment, the storage unit 3f stores a full-lift correction amount map Ma and a half-lift correction amount map Mb as the correction amount map M. The storage unit 3f also stores a drive control program for the fuel injection valve 100 and various calculated values.

[0056] Next, an example of the operation of the control processing unit 3b in the multi-stage injection control will be described with reference to Fig. 7. Fig. 7 is a flowchart for explaining an example of the operation of the control processing unit 3b in the multi-stage injection control.

[0057] 7, the control processing unit 3b determines whether the multiple fuel injections in one combustion cycle are full lift injections (step S1). Here, the current application period correction unit 3e determines whether the fuel injections are full lift injections based on a program stored in the storage unit 3f or a command input from the outside.

[0058] If it is determined in step S1 that full lift injection is being performed, the power supply period correction unit 3e refers to the full lift correction amount map Ma (step S2). Subsequently, the power supply period correction unit 3e determines the correction amount for the latter-stage power supply period Tib (step S3). Here, the power supply period correction unit 3e obtains a command value for the power supply halt period Tp based on a program stored in the storage unit 3f or a command input from the outside. The power supply period correction unit 3e refers to the full lift correction amount map Ma and determines the correction amount for the latter-stage power supply period Tib based on the command value for the power supply halt period Tp.

[0059] Thereafter, the control processing unit 3b causes the fuel injection valve 100 to inject fuel based on the correction amount of the rear-stage current conduction period Tib determined in step S3 (step S4). Here, the current conduction period correction unit 3e corrects the rear-stage current conduction period Tib based on the correction amount determined in step S3 to generate the corrected rear-stage current conduction period Tib. The current conduction control unit 3d energizes the solenoid coil 103 based on the front-stage current conduction period Tia based on the program stored in the storage unit 3f and the corrected rear-stage current conduction period Tib determined by the current conduction period correction unit 3e. As a result, the fuel injection valve 100 performs multi-stage injection of fuel.

[0060] On the other hand, if it is determined in step S1 that the fuel injection is not full-lift injection, the fuel injection is half-lift injection. Therefore, the power supply period correction unit 3e refers to the half-lift correction amount map Mb (step S5). Next, the power supply period correction unit 3e determines the correction amount for the rear-stage power supply period Tib (step S6). Here, the power supply period correction unit 3e obtains a command value for the power supply halt period Tp based on a program stored in the storage unit 3f or a command input from the outside. The power supply period correction unit 3e also obtains a command value for the front-stage power supply period Tia based on a program stored in the storage unit 3f or a command input from the outside. The power supply period correction unit 3e refers to the half-lift correction amount map Mb and determines the correction amount for the rear-stage power supply period Tib based on the command value for the power supply halt period Tp and the command value for the front-stage power supply period Tia.

[0061] Thereafter, the control processing unit 3b causes the fuel injection valve 100 to inject fuel based on the correction amount of the rear-stage current conduction period Tib determined in step S6 (step S7). Here, the current conduction period correction unit 3e corrects the rear-stage current conduction period Tib based on the correction amount determined in step S6 to generate the corrected rear-stage current conduction period Tib. The current conduction control unit 3d energizes the solenoid coil 103 based on the front-stage current conduction period Tia based on the program stored in the storage unit 3f and the corrected rear-stage current conduction period Tib determined by the current conduction period correction unit 3e. As a result, the fuel injection valve 100 performs multi-stage fuel injection.

[0062] The solenoid valve drive device 1 of this embodiment as described above controls the energization period Ti of the solenoid coil 103 provided in the fuel injection valve 100. The solenoid valve drive device 1 of this embodiment also causes the fuel injection valve 100 to inject fuel multiple times during one combustion cycle of the internal combustion engine. The solenoid valve drive device 1 of this embodiment includes a memory unit 3f, an energization period correction unit 3e, and an energization control unit 3d. The memory unit 3f stores a correction amount map M that indicates the relationship between the energization halt period Tp, which is the energization period Ti for the previous fuel injection during one combustion cycle, and the correction amount for the latter stage energization period Tib. The energization period correction unit 3e calculates a correction amount from a command value for the energization halt period Tp based on the correction amount map M, and corrects the latter stage energization period Tib based on the calculated correction amount. The energization control unit 3d energizes the solenoid coil 103 based on the post-stage corrected energization period, which is the post-stage energization period Tib corrected by the energization period correction unit 3e.

[0063] In the solenoid valve drive device 1 of this embodiment, a correction amount map M indicating the relationship between the power supply halt period Tp and the correction amount for the rear stage power supply period Tib is stored in the storage unit 3f. Furthermore, the correction amount for the rear stage power supply period Tib is calculated based on the correction amount map M from the command value for the power supply halt period Tp. Therefore, an increase in the load of the calculation process is suppressed compared to when the correction amount for the rear stage power supply period Tib is calculated without using the correction amount map M. Therefore, the solenoid valve drive device 1 of this embodiment can suppress an increase in the load of the calculation process caused by performing corrections related to fuel injection.

[0064] The fuel injection valve 100 also includes a movable core 109 and a fixed core 101. The movable core 109 is moved by energizing the solenoid coil 103. The fixed core 101 abuts against the movable core 109 at the maximum movement position of the movable core 109. In the solenoid valve drive device 1 of this embodiment, the storage unit 3f stores a full-lift correction amount map Ma as the correction amount map M. The full-lift correction amount map Ma indicates the relationship between the power supply halt period Tp and the correction amount when maximum drive (full-lift injection) is performed in which the movable core 109 abuts against the fixed core 101 in one fuel injection. Furthermore, the power supply period correction unit 3e calculates the correction amount from the command value of the power supply halt period Tp based on the full-lift correction amount map Ma when the fuel injection based on the front-stage power supply period Tia (front-stage injection) and the fuel injection based on the rear-stage power supply period Tib (rear-stage injection) are maximum drive (full-lift injection).

[0065] The solenoid valve drive device 1 of this embodiment can correct the rear stage current application period Tib using the full lift correction amount map Ma that matches the characteristics of the increase in residual magnetic force and effective boost voltage during full lift injection. Therefore, the solenoid valve drive device 1 of this embodiment can further reduce the difference between the fuel injection amount during rear stage injection of full lift injection and the design value.

[0066] Furthermore, in the solenoid valve drive device 1 of this embodiment, the storage unit 3f stores a half-lift correction amount map Mb as the correction amount map M. The half-lift correction amount map Mb indicates the relationship between the power supply halt period Tp and the correction amount when performing mid-drive (half-lift injection) in which the movable core 109 is not moved until it abuts against the fixed core 101 in one fuel injection. When the front-stage injection and rear-stage injection are mid-drive (half-lift injection), the power supply period correction unit 3e determines the correction amount from the command value for the power supply halt period Tp based on the half-lift correction amount map Mb.

[0067] The solenoid valve drive device 1 of this embodiment can correct the rear stage energization period Tib using the half-lift correction amount map Mb that matches the characteristics of the increase in residual magnetic force and effective boost voltage in half-lift injection. Therefore, the solenoid valve drive device 1 of this embodiment can further reduce the difference between the fuel injection amount in the rear stage injection of half-lift injection and the design value.

[0068] Furthermore, in the solenoid valve drive device 1 of this embodiment, the storage unit 3f stores a full-lift correction amount map Ma and a half-lift correction amount map Mb. Furthermore, the current supply period correction unit 3e determines whether the fuel injection is full-lift injection or half-lift injection. When the pre-injection and post-injection are full-lift injections, the current supply period correction unit 3e calculates a correction amount from the command value for the current supply halt period Tp based on the full-lift correction amount map Ma. When the pre-injection and post-injection are half-lift injections, the current supply period correction unit 3e calculates a correction amount from the command value for the current supply halt period Tp based on the half-lift correction amount map Mb.

[0069] The electromagnetic valve drive device 1 of this embodiment can correct the rear-stage current application period Tib by selecting a correction amount map M that suits the characteristics of either full-lift injection or half-lift injection of the fuel injection valve 100.

[0070] Furthermore, in the solenoid valve drive device 1 of this embodiment, the half-lift correction amount map Mb indicates the relationship between the correction amounts for the power supply halt period Tp and the rear stage power supply period Tib depending on the value of the front stage power supply period Tia. In the above embodiment, the half-lift correction amount map Mb indicates the relationship between the correction amounts for the power supply halt period Tp and the rear stage power supply period Tib for each range of the front stage power supply period Tia. Furthermore, the power supply period correction unit 3e calculates the correction amount from the command value for the front stage power supply period Tia and the command value for the power supply halt period Tp. In half-lift injection, the degree of influence on the rear stage injection varies greatly depending on the value of the front stage power supply period Tia. Therefore, by using such a half-lift correction amount map Mb, it is possible to correct the rear stage power supply period Tib in a way that suits the value of the front stage power supply period Tia.

[0071] Furthermore, in the electromagnetic valve drive device 1 of this embodiment, the power supply stop period Tp and the correction amount are related to each other so that the valve closing timing in the rear stage injection is advanced in response to the advancement of the valve opening timing in the rear stage injection caused by at least one of the residual magnetic force and the increase in the effective boost voltage due to the influence of the front stage injection. Therefore, the electromagnetic valve drive device 1 of this embodiment can suppress an increase in the fuel injection amount caused by the residual magnetic force and the increase in the effective boost voltage due to the influence of the front stage injection.

[0072] 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.

[0073] In the above embodiment, an example in which two fuel injections are performed in one combustion cycle has been described. However, this is not limited to this. Three or more fuel injections may be performed in one combustion cycle. In such a case, the earlier fuel injection of two temporally consecutive fuel injections is designated as a front-stage injection, and the later fuel injection (next fuel injection) is designated as a rear-stage injection, thereby enabling control similar to that of the above embodiment.

[0074] FIG. 8 is a schematic diagram illustrating a case where three or more fuel injections are performed in one fuel cycle. In FIG. 8, the upper part shows the change over time in the voltage applied to the solenoid coil 103, the middle part shows the change over time in the amount of movement of the movable core 109 from the valve-closed state, and the lower part shows the amount of variation in the fuel injection amount relative to the design value. As shown in FIG. 8, for example, when three or more fuel injections are performed in one fuel cycle, the valve-close detection unit 3c may detect the valve-close detection time Tx when fuel injections are performed based on the corrected post-stage current conduction period Tib, and calculate the difference between the detected valve-close detection time Tx and the estimated valve-close time obtained from the corrected post-stage current conduction period Tib. The post-stage correction current conduction period after the difference is calculated may be further corrected based on this difference. By further correcting the post-stage correction current conduction period in this manner, it is possible to suppress variations in the fuel injection amount from the design value due to individual differences in the fuel injection valve 100, temperature, and fuel pressure. [Explanation of symbols]

[0075] 1. Solenoid valve drive device 3c Closed valve detection section 3d Power supply control section 3e Current-carrying period correction section 3f Storage section 100 fuel injection valve 101 Fixed Core 103 Solenoid coil 109 Movable Core M Correction amount map Ma Full lift correction amount map Mb Half-lift correction map T1 Energization start time T2 Energization stop time Ti Power-on period Tia first stage energization period Tib Post-current period (post-current correction period) Tp Power-off period Tx Valve closure detection time

Claims

1. 1. An electromagnetic valve drive device that controls a period of time during which a solenoid coil provided in a fuel injection valve is energized, and causes the fuel injection valve to inject fuel multiple times during one combustion cycle of an internal combustion engine, a storage unit that stores a correction amount map that indicates a relationship between a power supply halt period from a completion time of a pre-stage power supply period, which is the power supply period for a previous fuel injection in the one combustion cycle, to a start time of a post-stage power supply period, which is the power supply period for a next fuel injection, and a correction amount for the post-stage power supply period; a current conduction period correction unit that calculates the correction amount from a command value for the current conduction halt period based on the correction amount map, and corrects the latter-stage current conduction period based on the calculated correction amount; an energization control unit that energizes the solenoid coil based on a post-stage corrected energization period that is the post-stage energization period corrected by the energization period correction unit; Equipped with The energization halt period and the correction amount are related to each other so that the valve closing timing in the next fuel injection is advanced in response to an advancement of the valve opening timing in the next fuel injection caused by at least one of a residual magnetic force and an increase in the effective boost voltage due to the influence of the previous fuel injection. Solenoid valve drive device.

2. the fuel injection valve includes a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, the storage unit stores, as the correction amount map, a maximum drive correction amount map indicating a relationship between the current supply suspension period and the correction amount when maximum drive is performed in which the movable core abuts against the fixed core by one fuel injection, The current conduction period correction unit calculates the correction amount from the command value of the current conduction halt period based on the maximum drive correction amount map when the fuel injection based on the first-stage current conduction period and the fuel injection based on the second-stage current conduction period are the maximum drive.

2. The electromagnetic valve drive device according to claim 1.

3. the fuel injection valve includes a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, the storage unit stores, as the correction amount map, a mid-way drive correction amount map that indicates a relationship between the current supply suspension period and the correction amount in a case where mid-way drive is performed in which the movable core is not moved until it abuts against the fixed core by one fuel injection, The current conduction period correction unit, when the fuel injection based on the first-stage current conduction period and the fuel injection based on the second-stage current conduction period are the mid-drive, calculates the correction amount from the command value of the current conduction halt period based on the mid-drive correction amount map.

3. The electromagnetic valve drive device according to claim 1.

4. the fuel injection valve includes a movable core that is moved by energizing the solenoid coil, and a fixed core that abuts against the movable core at a maximum movement position of the movable core, the storage unit stores, as the correction amount maps, a maximum drive correction amount map showing the relationship between the current supply suspension period and the correction amount when maximum drive is performed in which the movable core abuts against the fixed core with one fuel injection, and an intermediate drive correction amount map showing the relationship between the current supply suspension period and the correction amount when intermediate drive is performed in which the movable core is not moved until it abuts against the fixed core with one fuel injection, The current conduction period correction unit determines whether the fuel injection is the maximum drive or the midway drive, and when the fuel injection based on the front-stage current conduction period and the fuel injection based on the rear-stage current conduction period are the maximum drive, calculates the correction amount from a command value for the current conduction halt period based on the maximum drive correction amount map, and when the fuel injection based on the front-stage current conduction period and the fuel injection based on the rear-stage current conduction period are the midway drive, calculates the correction amount from the command value for the current conduction halt period based on the midway drive correction amount map.

2. The electromagnetic valve drive device according to claim 1.

5. the mid-drive correction amount map indicates a relationship between the power supply suspension period and the correction amount in accordance with the pre-stage power supply period; The current conduction period correction unit calculates the correction amount from a command value for the first-stage current conduction period and a command value for the current conduction halt period.

5. The electromagnetic valve driving device according to claim 3 or 4.

6. a valve closure detection unit that detects the closure of the fuel injection valve; The current conduction period correction unit calculates a difference between an estimated valve closing time obtained from the post-correction current conduction period and a valve closing detection time detected by the valve closing detection unit, and further corrects the post-correction current conduction period after calculation of the difference. The electromagnetic valve driving device according to any one of claims 1 to 5.

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