WO2017090320A1

WO2017090320A1 - Fuel injection control device and fule injection system

Info

Publication number: WO2017090320A1
Application number: PCT/JP2016/079377
Authority: WO
Inventors: 一片岡; 後藤　守康; 辰介山本
Original assignee: 株式会社デンソー
Priority date: 2015-11-27
Filing date: 2016-10-04
Publication date: 2017-06-01
Also published as: JP2017096233A

Abstract

As a fuel injection control device, an ECU (100) is equipped with an increase control unit (111), a target value setting unit (114), and an estimation unit (115). The increase control unit (111) controls the supply of electricity to a coil (70) so as to begin increasing the coil current when a needle (30) serving as a valve body is in the closed state, and to increase the coil current to a target value. The estimation unit (115) estimates the amount of overshoot when overshoot behavior occurs, wherein a movable core (40) moves as a result of the coil current reaching the target value and the needle (30) continues to move due to inertia even after the movable core makes contact with a stationary core (60). When the amount of overshoot estimated by the estimation unit (115) is equal to or exceeds a prescribed amount, the target value setting unit (114) lowers the target value in subsequent settings so as to be lower than the current setting.

Description

Fuel injection control device and fuel injection system

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2015-231964 filed on Nov. 27, 2015, and the contents thereof are disclosed in this specification.

The present disclosure relates to a fuel injection control device that controls the operation of a fuel injection valve and a fuel injection system including the fuel injection control device.

The fuel injection valve described in Patent Document 1 includes a fixed core that generates an electromagnetic attractive force when energized to a coil, a movable core that is attracted and moved by the fixed core, and a state that is movable relative to the movable core. And a valve body assembled to the movable core. When the coil is energized and the movable core is sucked into the fixed core, the valve element is engaged with the movable core that is moved by suction to open the valve, and fuel is injected from the nozzle hole.

Further, the control device described in Patent Document 1 starts the increase of the coil current flowing through the coil when the valve body is in the closed state, and executes the increase control for increasing the coil current to the target value. Increase suction power. When the increasing electromagnetic attraction force reaches the valve closing force applied to the valve body, the valve body starts the valve opening operation together with the movable core.

Here, the movable core attracted by energization collides with the fixed core, but when the collision speed is high, the collided movable core may rebound in the valve closing direction. In this case, if the valve element is fixed to the movable core against the above structure, the valve element also rebounds in the valve closing direction together with the movable core, and the opening degree by the valve element changes irregularly. As a result, the state of fuel injection from the nozzle hole becomes unstable, which hinders control of the fuel injection amount with high accuracy.

On the other hand, according to the above structure in which the valve body is movable relative to the movable core, the valve body is moved in the valve opening direction by inertia force even when the movable core bounces back in the valve closing direction. It becomes an overshoot behavior that keeps moving. Thereby, the recoil of the valve body in the valve closing direction is suppressed, the fuel injection state can be stabilized, and deterioration in the accuracy of the fuel injection amount can be suppressed.

As described above, when the electromagnetic attractive force increased by the ascent control increases to the valve closing force applied to the valve body, the opening operation of the movable core and the valve body is started. However, when the pressure of the fuel supplied to the fuel injection valve (that is, the supply fuel pressure) is small, the force with which the valve body is pressed against the valve closing side by the supply fuel pressure is weakened, so the valve closing force is small. . In this case, since the valve opening speed of the valve element is increased, the overshoot amount of the valve element is increased. Then, since the amount of movement of the valve body to the valve closing side due to the reaction after overshooting becomes large, it becomes impossible to sufficiently suppress the irregular opening of the valve body, and the accuracy of the fuel injection amount is sufficiently deteriorated. Can not be suppressed.

Although the overshoot amount can be reduced if the target value used for the ascent control is set low, there is a concern that if the target value is set too low, the electromagnetic attractive force does not increase sufficiently and the valve opening operation cannot be performed. Is done. Therefore, it is desirable to set the target value used for the lift control to the smallest possible value (that is, the optimum value) within the range in which the valve opening operation can be performed. However, such an optimum value varies due to deterioration of the fuel injection valve over time.

JP 2014-218976 A (corresponding to US2016 / 0061139A1)

The present disclosure has been made in view of the above problems, and an object thereof is to provide a fuel injection control device or a fuel injection system that suppresses deterioration in accuracy of the fuel injection amount.

In a first aspect of the present disclosure,
A fixed core that generates an electromagnetic attraction force when the coil is energized, a movable core that is attracted and moved by the fixed core, and a movable core that is assembled relative to the movable core and engaged with the moving movable core In a fuel injection control device applied to a fuel injection valve that has a valve body that opens by valve opening and that injects fuel from an injection hole in accordance with the valve opening operation,
An ascending control unit for controlling the power supply to the coil so as to start an increase in the coil current flowing through the coil when the valve body is in a closed state and to raise the coil current to a target value;
A target value setting unit for setting a target value;
As a result of raising the coil current to the target value, the overshoot amount of the valve element appears when the valve body continues to move with inertia even after the movable core moves and contacts the fixed core. An estimation unit for estimating
With
The target value setting unit provides a fuel injection control device that, when the overshoot amount estimated by the estimation unit is equal to or greater than a predetermined amount, lowers the target value compared to the current setting in the subsequent settings.

In a second aspect of the present disclosure,
A fixed core that generates an electromagnetic attraction force when the coil is energized, a movable core that is attracted and moved by the fixed core, and a movable core that is assembled relative to the movable core and engaged with the moving movable core A fuel injection valve for injecting fuel from the nozzle hole in accordance with the valve opening operation,
In a fuel injection system comprising a fuel injection control device that controls the operation of a fuel injection valve by controlling a coil current flowing in the coil,
The fuel injection control device
An ascending control unit for controlling the power supply to the coil so as to start an increase in the coil current flowing through the coil when the valve body is in a closed state and to raise the coil current to a target value;
As a result of raising the coil current to the target value, the overshoot amount of the valve element appears when the valve body continues to move with inertia even after the movable core moves and contacts the fixed core. An estimation unit for estimating
A target value setting unit that sets a target value so as to decrease a target value to be used after the next time when the overshoot amount estimated by the estimation unit is equal to or greater than a predetermined amount;
A fuel injection system is provided.

According to the first aspect and the second aspect described above, when setting the target value used by the ascending control unit, if the estimated overshoot amount is greater than or equal to the predetermined amount, the current and subsequent settings are The target value is lowered compared to the setting of. Therefore, the amount of overshoot can be reduced during the valve opening operation after the next time. Therefore, it can suppress that the opening degree by a valve body changes irregularly, and can suppress the precision deterioration of the fuel injection quantity resulting from an overshoot.

In addition, even if the increase in the overshoot amount recurs due to deterioration of the fuel injector over time after the target value is reduced as described above, the coil current target is exceeded when the overshoot amount exceeds a predetermined amount. The value is lowered. Therefore, even if the above recurrence occurs, the amount of overshoot can be reduced, and the deterioration of the accuracy of the fuel injection amount can be suppressed.

The figure which shows typically the fuel injection valve and fuel-injection control apparatus in 1st Embodiment of this indication. The figure which shows the valve closing state of the fuel injection valve in 1st Embodiment. The figure which shows the state in the middle of valve opening of the fuel injection valve in 1st Embodiment. The figure which shows the valve opening completion state of the fuel injection valve in 1st Embodiment. The figure which shows the state which the needle of the fuel injection valve in 1st Embodiment has overshooted. The figure which shows the change which arises with the passage of time of the voltage applied to a coil, coil current, electromagnetic attraction force, and lift amount when ECU shown in FIG. 1 implements injection control. The figure which shows the Ti-Q characteristic of the fuel injection valve shown in FIG. The flowchart which shows the process sequence which sets the target value of the coil current used for raise control by the microcomputer shown in FIG. The figure which shows typically the fuel injection valve used as the control object of a fuel-injection control apparatus in 2nd Embodiment of this indication. The figure which shows typically the fuel injection valve used as the control object of a fuel-injection control apparatus in 3rd Embodiment of this indication.

Hereinafter, a plurality of embodiments of the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to those described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other embodiments described above can be applied to other parts of the configuration.

(First embodiment)
A fuel injection valve 1 shown in FIG. 1 is mounted on an ignition type internal combustion engine (gasoline engine) of a vehicle, and directly injects fuel into a combustion chamber of the internal combustion engine. The fuel supplied to the fuel injection valve 1 is boosted by a high pressure pump (not shown). The high-pressure pump operates using the power of the internal combustion engine as a drive source.

As shown in FIG. 1, the fuel injection valve 1 includes a housing 20, a nozzle portion 10, a fixed core 60, a movable core 40, a needle 30 as a valve body, a movable plate 50, a first spring 80, a second spring 90, and A coil 70 and the like.

The housing 20 includes a first cylinder member 21, a second cylinder member 22, a third cylinder member 23, an outer peripheral member 25, and a resin mold portion 26. The first cylinder member 21, the second cylinder member 22, and the third cylinder member 23 are all formed in a substantially cylindrical shape, and are coaxial in the order of the first cylinder member 21, the second cylinder member 22, and the third cylinder member 23. Arranged and connected to each other. The outer peripheral member 25 is in contact with the outer peripheral surfaces of the first cylindrical member 21 and the third cylindrical member 23. The 1st cylinder member 21, the 3rd cylinder member 23, and the outer periphery member 25 are formed, for example with magnetic materials, such as ferritic stainless steel. On the other hand, the second cylindrical member 22 is formed of a nonmagnetic material such as austenitic stainless steel, for example.

The nozzle unit 10 is provided at the end of the first cylinder member 21 and is formed in a metal disk shape. A nozzle hole 11 that penetrates the nozzle portion 10 in the plate thickness direction is formed in the center of the nozzle portion 10. An annular valve seat 12 is formed on one surface of the nozzle portion 10 so as to surround the nozzle hole 11. The nozzle portion 10 is connected to the first cylinder member 21 such that the side wall is fitted to the inner wall of the first cylinder member 21.

The fixed core 60 is provided at the end of the third cylindrical member 23, and is formed in a substantially cylindrical shape by a magnetic material such as ferritic stainless steel, for example. The fixed core 60 is provided inside the housing 20. Note that the fixed core 60 and the nozzle portion 10 are fixed to the housing 20 by welding.

The needle 30 is formed in a rod shape from a metal such as martensitic stainless steel. The needle 30 is accommodated in the housing 20 so as to be capable of reciprocating in the axial direction. The needle 30 is formed at a rod-like main body 32 extending in the axial direction, a seal portion 31 formed at an end portion of the main body 32 on the nozzle portion 10 side, and an end portion of the main body 32 opposite to the nozzle portion 10 side. And a flange portion 33. The needle 30 opens and closes the nozzle hole 11 when the seal portion 31 is separated from the valve seat 12 (that is, separated) or abuts (that is, seated) on the valve seat 12. Hereinafter, the direction in which the needle 30 is separated from the valve seat 12 is referred to as a valve opening direction, and the direction in which the needle 30 contacts the valve seat 12 is referred to as a valve closing direction. The flange 33 side of the main body 32 is formed in a hollow cylindrical shape, and a hole 34 that connects the inner wall 321 and the outer wall 322 of the main body 32 is formed. The flange portion 33 has a disk shape that expands toward the inner wall 24 of the housing 20.

The movable core 40 is formed in a substantially cylindrical shape by a magnetic material such as ferritic stainless steel. The movable core 40 is accommodated in the housing 20 in a state where the movable core 40 can reciprocate between the fixed core 60 and the nozzle portion 10. A through hole 44 is formed in the center of the movable core 40. The inner wall of the through hole 44 of the movable core 40 and the outer wall 322 of the main body 32 of the needle 30 are slidable, and the outer wall 42 of the movable core 40 and the inner wall 24 of the housing 20 are slidable. Thereby, the movable core 40 can reciprocate inside the housing 20 while sliding with the needle 30 and the housing 20.

The movable core 40 has an accommodation recess 45 formed on the end surface 41 on the fixed core 60 side so as to expand annularly from the inner wall of the through hole 44 in the radially outward direction. In addition, the movable core 40 has a fitting groove portion 46 formed on the end surface 41 on the fixed core 60 side so as to expand in an annular shape radially outward from the end portion on the opposite side of the bottom wall 452 of the housing recess 45. The accommodating recess 45 accommodates the flange portion 33 of the needle 30, and a movable plate 50 described later is fitted into the fitting groove portion 46.

The movable plate 50 is formed in a disk shape having a diameter larger than that of the housing recess 45 by a metal such as martensitic stainless steel, and has a hole 51 in the center. The movable plate 50 is provided on the opposite side of the movable core 40 from the nozzle portion 10 so as to be in contact with the movable core 40 and the flange portion 33 of the needle 30. The movable plate 50 is provided so as to be fitted into the fitting groove 46.

The coil 70 is formed in a substantially cylindrical shape and is provided so as to surround the radially outer side of the second cylinder member 22 and the third cylinder member 23. A resin mold portion 26 is filled between the first cylinder member 21, the second cylinder member 22, the third cylinder member 23, and the outer peripheral member 25.

When electric power is supplied to the coil 70 and a magnetic force is generated in the coil 70, a magnetic circuit is formed in the fixed core 60, the movable core 40, the first cylindrical member 21, the third cylindrical member 23, and the outer peripheral member 25. Thereby, the electromagnetic attractive force acts on the movable core 40, and the movable core 40 is attracted to the fixed core 60. At this time, since the bottom wall 452 of the housing recess 45 abuts against the flange 33 of the needle 30, the needle 30 moves together with the movable core 40 toward the fixed core 60, that is, in the valve opening direction. Thereby, the seal part 31 is separated from the valve seat 12, and the nozzle hole 11 is opened. In addition, the movable core 40 is restricted from moving in the valve opening direction when the end surface 41 abuts against the fixed core 60.

The first spring 80 abuts on the movable plate 50 and applies an elastic force to urge the movable core 40 and the needle 30 in the valve closing direction. The second spring 90 urges the movable plate 50 toward the fixed core 60 (that is, the valve opening direction) by contacting the movable core 40 and applying an elastic force. The urging force of the first spring 80 is set larger than the urging force of the second spring 90. Therefore, in a state where power is not supplied to the coil 70, the needle 30 is in a closed state in which the seal portion 31 is in contact with the valve seat 12.

As shown in FIG. 2, when energization of the coil 70 is turned off, the movable plate 50 contacts the needle 30 and the movable core 40 by the urging force of the first spring 80 and the second spring 90. Specifically, the lower end surface 53 of the movable plate 50 contacts the end surface 331 of the flange portion 33 of the needle 30 and the bottom wall 461 of the insertion groove portion 46 of the movable core 40. Here, the axial length of the flange 33 is L1, and the axial distance between the lower end surface 53 of the movable plate 50 and the bottom wall 452 of the housing recess 45 is L2. The flange 33, the movable plate 50, the housing recess 45, and the fitting groove 46 are formed so as to satisfy the relationship L1 <L2.

Further, the axial distance between the lower end surface 332 of the flange 33 and the bottom wall 452 of the housing recess 45 is G1, and the axial distance between the end surface 41 of the movable core 40 and the end surface of the fixed core 60 on the movable core 40 side. Is G2. The flange 33, the movable plate 50, the housing recess 45, the fitting groove 46, the movable core 40, and the fixed core 60 are provided so as to satisfy the relationship of G1 <G2 and G1 = L2-L1.

A substantially cylindrical fuel introduction pipe 62 is press-fitted and welded to the end of the third cylinder member 23. The fuel that has flowed in from the fuel introduction pipe 62 flows in order through the fixed core 60, the hole 51 of the movable plate 50, the inside of the main body 32 of the needle 30, the hole 34 of the needle 30, and the first cylindrical member 21 and the needle 30. To do. In a state where the needle 30 is opened by energization of the coil 70, the fuel that has circulated as described above circulates between the seal portion 31 and the valve seat 12 and is then injected from the injection hole 11.

Next, the operation of the fuel injection valve 1 of this embodiment will be described with reference to FIGS.

In a state where the power supply to the coil 70 is turned off, as shown in FIG. 2, the first spring 80 biases the movable plate 50 to bias the needle 30 in the valve closing direction, and the second spring 90 The movable core 40 is urged toward the fixed core 60 side. The lower end surface 53 of the movable plate 50 is in contact with the end surface 331 of the flange portion 33 of the needle 30 and the bottom wall 461 of the fitting groove portion 46 of the movable core 40, and as described above, L1 <L2 and G1 <G2. Yes. Thereby, it will be in the obstruction | occlusion state in which the seal part 31 of the needle 30 was seated on the valve seat 12, and the injection hole 11 will be in the closed state.

When energization of the coil 70 is turned on, the movable core 40 is attracted by the fixed core 60 and moved to the fixed core 60 side as shown in FIG. The movable plate 50 is pushed by the movable core 40 and moves toward the first spring 80 against the urging force of the first spring 80. Further, the movable core 40 is accelerated by a predetermined distance G1 and collides with the lower end surface 332 of the collar portion 33 of the needle 30 with kinetic energy corresponding to the acceleration distance. Due to this collision, the needle 30 starts to move rapidly in the valve opening direction, the seal portion 31 is separated from the valve seat 12, and fuel is injected from the injection hole 11.

The movable core 40 continues to move after colliding with the needle 30 and collides with the fixed core 60 as shown in FIG. That is, the movement of the movable core 40 is restricted. The needle 30 is urged in the valve opening direction by the movable core 40 in a state where the collar portion 33 is engaged with the bottom wall 452. The period of biasing in this way is a period from when the movable core 40 collides with the needle 30 to when the movable core 40 collides with the fixed core 60.

While the movable core 40 stops moving, the needle 30 moves away from the movable core 40 as shown in FIG. 5 and continues to move against the elastic force of the first spring 80 due to inertia. The first spring 80 pressed against the needle 30 via the movable plate 50 contracts to the limit, and then moves the movable plate 50 and the needle 30 back to the valve closing direction. The movable plate 50 and the needle 30 pushed back in this way stop moving in the state of FIG.

In this way, the behavior in which the needle 30 continues to move due to inertia even after the movable core 40 moves and contacts the fixed core 60 is called overshoot. As shown in FIG. 5, the overshoot amount L3 is a separation distance in the axial direction between the needle 30 and the movable core 40. Specifically, it is the distance in the axial direction from the lower end surface 332 of the flange 33 to the bottom wall 452 of the housing recess 45.

When the power supply to the coil 70 is turned off, the electromagnetic attraction force decreases, and when the energization force falls below the valve opening holding force, the movable plate 50, the movable core 40, and the needle 30 move in the valve closing direction. Specifically, first, the movable plate 50 is urged toward the needle 30 by the first spring 80, thereby starting movement in the valve closing direction together with the movable core. Thereafter, the movable plate 50 comes into contact with the collar portion 33 of the needle 30 and urges the needle 30 in the valve closing direction. In other words, the elastic force of the first spring 80 is transmitted to the needle 30 via the movable plate 50, and the needle 30 starts the valve closing operation by the elastic force. The needle 30 moving in the valve closing direction stops moving when the seal portion 31 comes into contact with the valve seat 12.

While the movement of the needle 30 stops, the movable plate 50 also stops moving, while the movable core 40 moves away from the movable plate 50 and continues to move against the elastic force of the second spring 90 due to inertia. The second spring 90 pressed against the movable core 40 contracts to the limit and then moves the movable core 40 back to the movable plate 50 side. The movable core 40 pushed back in this way again comes into contact with the movable plate 50 and moves together with the movable plate 50 in the valve opening direction. At this time, since the movable core 40 is not in contact with the needle 30, even if the movable core 40 is pushed back and moved as described above, the needle 30 does not move in the valve opening direction. Thereafter, the movable plate 50 is again pressed in the valve closing direction by the first spring 80, and the movable plate 50 moves in the valve closing direction together with the movable core 40. That is, the movable core 40 vibrates in the axial direction, and when the kinetic energy of the movable core 40 is lost, the movable plate 50 stops moving in the state of FIG. 2 where the movable plate 50 contacts the needle 30 and the movable core 40.

In short, the movable plate 50 moves in the axial direction together with the movable core 40, but the movement start timing of the movable plate 50 is the same as the movement start timing of the movable core 40 regardless of whether the valve is closed or opened. . On the other hand, the movement start timing of the needle 30 is delayed from the movement start timing of the movable core 40 regardless of whether the needle 30 is closed or opened.

The movable plate 50 is configured separately from the movable core 40 and provides a moving member that moves together with the movable core 40. The movable plate 50 is pushed and moved by the movable core 40 in the valve opening direction and moved by the first spring 80 in the valve closing direction. When the first spring 80 moves while being pushed, the movable plate 50 functions as a valve closing force transmission member that transmits the elastic force of the first spring 80 to the needle 30.

Next, the hardware configuration of the fuel injection control device that controls the energization state of the coil 70 will be described with reference to FIG. The fuel injection control device is provided by the ECU 100 which is an electronic control device. A fuel injection system is provided by the fuel injection valve 1 and the ECU 100. The ECU 100 includes a microcomputer (microcomputer 110), a booster circuit 120, and the like.

The microcomputer 110 includes a central processing unit (CPU), a non-volatile memory (ROM), a volatile memory (RAM), and the like. Based on the load and engine speed of the internal combustion engine, the required fuel injection quantity Qreq and The target injection start time is calculated. A memory 130 of the microcomputer 110 in FIG. 1 is a memory including the above-described ROM and RAM. It should be noted that a characteristic line (see FIG. 7) showing the relationship between the energization time Ti and the injection amount Q is obtained by testing in advance, and the energization time Ti to the coil 70 is controlled according to the characteristic line. Control the quantity Q.

For example, a Ti-Q map that is a map showing the relationship between the energization time Ti and the injection amount Q is created based on the above characteristic line, and the Ti-Q map is stored in the memory. Then, the energization time Ti suitable for the required injection amount Qreq is set with reference to the Ti-Q map. The higher the pressure of the fuel supplied to the fuel injection valve 1 (hereinafter referred to as supply fuel pressure Pf), the shorter the energization time Ti. Therefore, a Ti-Q map is created and stored for each supply fuel pressure Pf, and the Ti-Q map to be referred to is switched according to the supply fuel pressure Pf at the time of injection.

Supplied fuel pressure Pf is detected by a fuel pressure sensor 200 shown in FIG. The fuel pressure sensor 200 is attached to the housing 20 and detects the pressure of the fuel flowing through the fuel passage inside the housing 20. Specifically, the fuel pressure sensor 200 is disposed at a portion downstream of the fuel introduction pipe 62 and upstream of the movable plate 50. The microcomputer 110 calculates the supply fuel pressure Pf based on the detection signal output from the fuel pressure sensor 200. When executing this calculation, the microcomputer 110 functions as the fuel pressure acquisition unit 116 shown in FIG.

Booster circuit 120 boosts battery voltage Vbatt supplied from the vehicle battery to generate boost voltage Vboost (see FIG. 6A). The ECU 100 includes a circuit that detects a coil current that is a current flowing through the coil 70. Specifically, when the microcomputer 110 detects a voltage drop due to the shunt resistor, the microcomputer 110 calculates and acquires the coil current. The microcomputer 110 switches between the boost voltage Vboost and the battery voltage Vbatt to be applied to the coil 70 according to the acquired coil current value.

Next, the electromagnetic attractive force (that is, valve opening force) generated by flowing the coil current will be described in detail.

As the ampere turn AT, which is the magnetomotive force generated by the fixed core 60, increases, the electromagnetic attractive force increases. That is, if the number of turns of the coil 70 is the same, the electromagnetic attraction force increases as the coil current increases and the ampere turn AT increases. However, it takes time for the suction force to reach a maximum value after energization is started. In the present embodiment, the electromagnetic attractive force when saturated and reaches the maximum value is referred to as a static attractive force Fb.

Further, the electromagnetic attraction force necessary for the needle 30 to start the valve opening operation is referred to as a necessary valve opening force Fa. Note that the higher the fuel pressure supplied to the fuel injection valve 1 is, the larger the electromagnetic suction force (that is, the valve opening start suction force) necessary for the needle 30 to start the valve opening operation. Further, the valve opening start suction force increases according to various situations such as when the viscosity of the fuel is large. Therefore, the valve opening start suction force when the situation in which the valve opening start suction force is maximized is assumed is defined as the required valve opening force Fa.

FIG. 6A shows the waveform of the voltage applied to the coil 70 when the fuel injection is performed once. As shown in the figure, the boost voltage Vboost is applied to start energization at the voltage application start time t0 commanded by the injection command signal, that is, the start time of the energization time Ti. Then, with the start of energization, the coil current rises to the first target value I1 (see the first target value I1 indicated by the one-dot chain line in FIG. 6B). The energization is turned off at time t1 when the detected coil current reaches the first target value I1. In short, control is performed so that the coil current is raised to the first target value I1 by applying the boost voltage Vboost by the first energization. Control in which the coil current is increased by the boost voltage Vboos in this way is referred to as increase control, and the microcomputer 110 when executing the increase control functions as the increase control unit 111 illustrated in FIG.

Thereafter, energization with the battery voltage Vbatt is controlled so that the coil current is maintained at the second target value I2 set to a value lower than the first target value I1. Specifically, by repeatedly turning on and off the battery voltage Vbatt so that the deviation between the coil current detection value and the second target value I2 is within a predetermined range, the average value of the fluctuating coil current becomes the second target value I2. The duty is controlled so that The second target value I2 is set to a value such that the static suction force Fb is greater than or equal to the required valve opening force Fa. Control in which the coil current is held at the second target value I2 at the battery voltage Vbatt in this way is called pickup control, and the microcomputer 110 when executing the pickup control functions as the pickup control unit 112 shown in FIG. In the pickup control, the electromagnetic attractive force increases. The pick-up control improves the certainty that the electromagnetic attraction force rises to the required valve opening force Fa and starts the valve opening operation.

Thereafter, energization by the battery voltage Vbatt is controlled so that the coil current is maintained at the third target value I3 set to a value lower than the second target value I2. Specifically, by repeatedly turning on and off the battery voltage Vbatt so that the deviation between the coil current detection value and the third target value I3 is within a predetermined range, the average value of the fluctuating coil current becomes the third target value I3. The duty is controlled so that Control in which the coil current is held at the third target value I3 at the battery voltage Vbatt in this way is referred to as hold control, and the microcomputer 110 during the hold control functions as the hold control unit 113 shown in FIG. The hold control is for maintaining the electromagnetic attraction force at or above the valve opening holding force Fc.

As shown in FIG. 6 (c), the electromagnetic attractive force continues to increase during a period from the start of energization, that is, from the increase control start time (t0) to the pickup control end time (t3). The rate of increase of the electromagnetic attractive force is slower in the pickup control period (t2 to t3) than in the increase control period (t0 to t1). The first target value I1, the second target value I2, and the pickup control period are set so that the suction force exceeds the required valve opening force Fa during the period (t0 to t3) during which the suction force increases. Yes.

During the hold control period (t4 to t5), the suction force is held at a predetermined value. The third target value I3 is set so that the predetermined value is higher than the valve opening holding force Fc required to hold the valve open state. The valve opening holding force Fc is smaller than the required valve opening force Fa.

The vertical axis in FIG. 6D indicates the lift amount that is the movement amount when the needle 30 is opened. At time t10 when the suction force increases and reaches the required valve opening force Fa, the movable core 40 starts the lift-up movement. Thereafter, at time t11 when the movable core 40 collides with the needle 30, the needle 30 starts the valve opening operation, and fuel injection from the injection hole 11 is started. Thereafter, as shown by the solid line in the figure, the lift amount of the needle 30 increases as the lift amount of the movable core 40 increases. Thereafter, at time t12 when the movable core 40 collides with the fixed core 60, the needle 30 leaves the movable core 40 and overshoots.

Thereafter, the movable core 40 starts the lift-down movement together with the movable plate 50 at the time when the attraction force decreases with the energization of the coil 70 and reaches the valve opening holding force Fc. Thereafter, at time t <b> 13 when the movable plate 50 contacts the needle 30, the needle 30 starts a lift-down movement together with the movable core 40. Thereafter, at time t14 when the needle 30 abuts on the seal portion 31, fuel injection from the nozzle hole 11 is stopped.

FIG. 7 shows a characteristic line representing the relationship between the energization time Ti and the injection amount Q. The solid line in the figure is the characteristic line when the supply fuel pressure is 10 MPa, and the dotted line is the characteristic line when the supply fuel pressure is 20 MPa. Of the characteristic lines, the area indicated by reference numeral A1 is referred to as a partial area, and the area indicated by reference numeral A2 is referred to as a full lift area. When fuel is injected during the energizing time Ti in the partial region A1 (that is, partial injection), the valve closing operation is started before the movable core 40 collides with the fixed core 60, that is, before the needle 30 reaches the full lift position. A small amount of fuel is injected. The full lift position is a lift position of the needle 30 when the movable core 40 collides with the fixed core 60. On the other hand, when fuel is injected during the energization time Ti in the full lift region A2 (that is, full lift injection), the valve 30 starts the valve closing operation after the needle 30 reaches the full lift position, so that compared with the case where fuel is injected in the partial region A1. The injection amount increases.

When an overshoot occurs in the behavior of the needle 30, the waveform of the characteristic line pulsates as shown by the alternate long and short dash line. This pulsation waveform is generated in a region adjacent to the partial region A1 in the full lift region A2. Therefore, in such a region where a pulsation waveform can occur, the injection amount Q changes depending on the presence or absence of overshoot even if the energization time Ti and the supply fuel pressure are the same.

FIG. 8 shows a processing procedure for setting the first target value I1 used for the ascent control, which is repeatedly executed at a predetermined cycle by the microcomputer 110 during the operation period of the internal combustion engine. First, in step S10 of FIG. 8, the first target value I1 is set according to the supply fuel pressure Pf. The supply fuel pressure Pf used for this setting is a value detected by the fuel pressure sensor 200 immediately before the start of injection. The value of the first target value I1 suitable for the supply fuel pressure Pf is set in advance by a test or the like for each different supply fuel pressure Pf.

Describing the concept of this setting, if the first target value I1 is too small, there is a concern that the electromagnetic attractive force cannot be increased to the required valve opening force Fa. Even if the valve opening force Fa can be increased, the rising speed becomes extremely slow, and the delay time from the start of energization to the start of the valve opening operation becomes long. On the other hand, if the first target value I1 is excessive, the electromagnetic attractive force is excessively increased, and the speed at which the movable core 40 collides with the fixed core 60 is increased. Then, there is a concern about accelerated wear of the contact surfaces of the movable core 40 and the fixed core 60. Further, since the collision speed is increased, the overshoot amount L3 becomes excessive, and a large pulsation is generated in the characteristic line shown in FIG. 7, making it difficult to control the injection amount with high accuracy. In view of these points, the value of the first target value I1 suitable for the supply fuel pressure Pf is set, and the first target value I1 is set to a larger value as the supply fuel pressure Pf is higher.

And the information showing the relationship between the supply fuel pressure Pf and the first target value I1 is stored in the ECU 100 in the form of a map M shown in FIG. In step S10, referring to this map M, a first target value I1 is set based on the supplied fuel pressure Pf.

In the subsequent step S11, the overshoot amount L3 is estimated based on the change in pressure detected by the fuel pressure sensor 200. Hereinafter, the estimation method will be described. The pressure detected by the fuel pressure sensor 200 starts to decrease with the start of fuel injection from the nozzle hole 11. Thereafter, the pressure drop stops as the needle 30 reaches the full lift position. Thereafter, the pressure starts to increase with the start of the valve closing operation of the needle 30 and returns to the pressure before the start of injection with the valve closing.

Thus, the pressure change detected by the fuel pressure sensor 200, that is, the waveform representing the pressure change is correlated with the behavior of the needle 30. A pulsation caused by overshoot is superimposed on this pressure waveform. The magnitude of the pulsation or the superposition period has a correlation with the overshoot amount L3. Specifically, the flange portion 33 of the needle 30 when overshooting pressurizes the fuel located in the upstream portion of the flange portion 33 in the fuel passage formed inside the housing 20, and locally The pressure will increase. As this pressure rise propagates to the fuel pressure sensor 200, pulsation caused by overshoot is superimposed on the pressure waveform. Therefore, it can be said that the overshoot amount L3 is larger as the period of pressure increase due to overshoot is longer. Moreover, it can be said that the overshoot amount L3 is larger as the pressure increase amount due to the overshoot is larger.

Therefore, if the pulsation caused by the overshoot that is superimposed on the pressure waveform detected by the fuel pressure sensor 200 is acquired in step S11, the overshoot amount L3 can be estimated from the shape of the pulsation.

In subsequent step S12, it is determined whether or not the overshoot amount L3 estimated in step S11 is equal to or larger than a predetermined amount Lth set in advance. If it is determined that the value is greater than or equal to the predetermined amount Lth, in subsequent step S13, a reduction correction is performed such that the value of the first target value I1 stored in the map M is corrected to a value reduced by a predetermined amount. In this reduction correction, all of the plurality of first target values I1 set for different supply fuel pressures Pf are corrected to values reduced by a predetermined amount. In the subsequent step S14, the first target value I1 stored in the map M is rewritten and updated with the value corrected in step S13.

As described above, the ECU 100 according to this embodiment includes the increase control unit 111 that increases the coil current to the first target value I1, the target value setting unit 114 that sets the first target value I1, and the overshoot amount of the needle 30. And an estimation unit 115 that estimates L3. Then, when the overshoot amount L3 estimated by the estimation unit 115 is equal to or greater than the predetermined amount Lth, the target value setting unit 114 lowers the first target value I1 compared to the current setting in the subsequent settings. . Specifically, in step S13 of FIG. 8, the first target value I1 stored in the map M is reduced and corrected, and in the next setting, the increase control is performed using the first target value I1 after the reduction correction. . Therefore, the overshoot amount L3 can be reduced during the valve opening operation after the next time. In the example of FIG. 6, when the first target value I1 indicated by the alternate long and short dash line in FIG. 6B is reduced to the first target value I1 indicated by the dotted line, the current indicated by the solid line in FIG. Of the waveform, the portion corresponding to the ascending control period decreases as shown by the dotted line. As a result, the lift amount waveform shown by the solid line in FIG. 6D becomes a waveform with a slow rising speed as shown by the dotted line, and the overshoot is reduced. Therefore, since the opening degree by the needle 30 can be prevented from changing irregularly, the injection amount Q with respect to the energization time Ti can be prevented from changing due to overshoot, and the deterioration of the accuracy of the fuel injection amount due to overshoot can be suppressed.

Furthermore, in the present embodiment, the target value setting unit 114 sets the first target value I1 according to the supply fuel pressure Pf acquired by the fuel pressure acquisition unit 116. Further, the target value setting unit 114 decreases the first target value I1 corresponding to the supply fuel pressure Pf when at least the overshoot amount L3 is equal to or greater than the predetermined amount among the first target value I1 for each supply fuel pressure Pf.

For example, of the first target value I1 for each supply fuel pressure Pf stored in the map M shown in FIG. 8, as a result of performing the increase control using the first target value corresponding to Pf = 5 MPa and performing fuel injection, the overshoot Assume that the amount L3 is equal to or greater than a predetermined amount Lth. In the case of this assumption, among the first target values I1 for each supply fuel pressure Pf stored in the map M, reduction correction is performed for at least the first target value corresponding to Pf = 5 MPa. According to this, when the fuel is injected in the situation of Pf = 5 MPa after the next time, it is possible to improve the reliability of preventing the recurrence that the overshoot amount L3 becomes equal to or greater than the predetermined amount Lth.

Here, examples of the fuel injection valve in which the needle 30 is configured to be movable relative to the movable core 40 include a core boost type and a normal type described below. The fuel injection valve 1 according to the present embodiment is a core boost type, and the core boost type is more likely to overshoot than the normal type. Therefore, according to the present embodiment in which the fuel injection control device that executes the reduction correction is applied to the core boost type fuel injection valve 1, the effect of suppressing the overshoot by the reduction correction is more remarkably exhibited.

The core boost type fuel injection valve 1 has a structure in which the movable core 40 engages with the needle 30 and starts the valve opening operation after the movable core 40 is attracted to the fixed core 60 and moved by a predetermined amount. That is, in the valve closed state shown in FIG. 2, the engagement is not performed, and a gap of a predetermined distance G <b> 1 is formed between the needle 30 and the movable core 40 in the axial direction. As a result, when the movable core 40 is sucked and starts moving, the force for opening the needle 30 is unnecessary, and the movable core 40 is engaged with the needle 30 after moving by a predetermined distance G1 and gaining momentum. Then, the needle 30 starts the valve opening operation.

On the other hand, the normal type fuel injection valve has a structure in which the movable core is attracted to the fixed core and starts moving, and at the same time, the movable core engages with the needle to start the valve opening operation. That is, in the valve-closed state shown in FIG. 2, the above engagement has already been made, and no gap in the axial direction is formed between the needle and the movable core.

In the case of the core boost type, the first spring 80 that urges the needle 30 toward the valve closing side is brought into contact with the movable plate 50. Therefore, when the needle 30 is closed, the elastic force by the first spring 80 is transmitted to the needle 30 via the movable plate 50. However, in the valve open state shown in FIG. 4, the elastic force of the first spring 80 is not transmitted to the needle 30, and the needle 30 is not pressed against the valve closing side by the elastic force.

On the other hand, in the case of the normal type, the movable plate 50 is unnecessary, so that the first spring comes into contact with the needle. Therefore, the needle is pressed toward the valve closing side by the elastic force not only during the valve closing operation but also during the valve opening operation.

As described above, in the case of the normal type, the elastic force is always applied to the valve closing side during the valve opening operation of the needle, so that overshoot hardly occurs. On the other hand, in the case of the core boost type, the elastic force to the valve closing side is not applied to the needle from the start of the valve opening operation of the needle 30 until the movable core 40 collides with the fixed core 60. Prone to occur.

Furthermore, in this embodiment, the following effects are exhibited by adopting the above-described core boost type fuel injection valve 1. That is, the flange 33, the movable plate 50, the housing recess 45, and the fitting groove 46 are formed so as to satisfy the relationship L1 <L2 in a state where the movable core 40 and the movable plate 50 are in contact with each other. Thereby, a gap having a predetermined distance G1 in the axial direction is formed between the lower end surface 332 of the flange 33 and the bottom wall 452 of the housing recess 45. For this reason, when the movable core 40 is attracted in the valve opening direction by the magnetic force of the coil 70 supplied with electric power, the movable core 40 is accelerated by a predetermined distance G1 and then collides with the collar portion 33 of the needle 30. Therefore, the needle 30 can be opened quickly using the energy at the time of the collision.

Further, in the present embodiment, a gap of a predetermined distance G1 is formed between the lower end surface 332 of the flange 33 and the bottom wall 452 of the housing recess 45. Therefore, it can suppress that the movable core 40 pushed back by the 2nd spring 90 after pressing the 2nd spring 90 hits the collar part 33 of the needle 30 which is valve-closing. Therefore, the occurrence of secondary valve opening by the movable core 40 pushed back by the second spring 90 can be suppressed.

(Second Embodiment)
In the fuel injection valve 1 of the first embodiment, a flat plate-shaped movable plate 50 is employed as a moving member that moves together with the movable core 40. In contrast, in the fuel injection valve 1A of the second embodiment shown in FIG. 9, a bottomed cylindrical cup-shaped moving member 50B is employed. The moving member 50B includes a disc-shaped disc portion 501 and a cylindrical portion 502 having a cylindrical shape.

The disc portion 501 is disposed so as to face the end surface 331 of the flange portion 33 and be in contact with the end surface 331. The cylindrical portion 502 has a shape extending from the outer peripheral end of the disc portion 501 toward the axial injection hole 11, and is disposed inside the accommodating recess 45 of the movable core 40 and the cylinder of the fixed core 60. The outer peripheral surface of the cylindrical portion 502 is positioned in the radial direction by the inner wall 63 of the fixed core 60. That is, in the moving member 50 </ b> B, the cylindrical portion 502 can slide in the axial direction along the inner wall 63 of the fixed core 60.

The collar portion 33 is disposed inside the cylindrical portion 502. The inner peripheral surface of the cylindrical portion 502 can slide in the axial direction with respect to the outer peripheral surface of the flange portion 33. A hole 501 a penetrating in the axial direction is formed in the central portion of the disc portion 501. The hole 501 a communicates with a passage inside the needle 30, that is, a passage formed by the inner wall 321.

In the movable core 40, a recess 451 that is further recessed toward the nozzle hole 11 is formed on the bottom wall portion of the housing recess 45. In the valve-closed state shown in FIG. 9, a gap is formed between the lower end surface 332 of the flange 33 and the bottom wall 451 a of the recess 451. The axial distance of this gap corresponds to the distance G1 shown in FIG. 2, and various dimensions are set so as to satisfy the relationship of G1 <G2 and G1 = L2-L1 as in FIG. .

According to the present embodiment, the moving member 50B is guided by the inner wall 63 of the fixed core 60 and is provided so as to be capable of reciprocating along the axial direction. The flange portion 33 of the needle 30 is guided by the inner peripheral surface 502a of the cylindrical portion 502, and is accommodated in the cylindrical portion 502 so as to be capable of reciprocating in the axial direction. Thereby, the needle 30 is guided to the inner wall 63 of the fixed core 60 via the moving member 50B. Such a configuration is advantageous in improving the coaxiality of the fixed core 60, the moving member 50 </ b> B, and the needle 30 compared to a configuration in which the needle 30 is guided by the inner wall 24 of the housing 20 via the movable core 40, for example. It is. For this reason, in the reciprocating movement of the needle 30 in the axial direction, the needle 30 can be prevented from being inclined in the radial direction. Therefore, the stability of the reciprocating movement of the needle 30 in the axial direction can be improved.

(Third embodiment)
The moving member 50B according to the second embodiment includes a disc portion 501 and a cylindrical portion 502, and the disc portion 501 and the cylindrical portion 502 are integrally formed of resin or metal. On the other hand, the disc part 503 and the cylindrical part 504 which the moving member of the fuel injection valve 1B according to the third embodiment shown in FIG. 10 has are formed by separate members.

The disk part 503 has a disk-shaped plate part 503b and a cylindrical tube part 503c. The plate portion 503b faces the end surface 331 of the flange portion 33 and is disposed so as to be able to contact the end surface 331. A hole 503a penetrating in the axial direction is formed in the central portion of the plate portion 503b. The cylindrical portion 503 c has a shape extending from the inner peripheral end of the plate portion 503 b to the axial anti-injection hole side, and is disposed inside the first spring 80.

The plate portion 503b faces the end surface 331 of the flange portion 33 and is disposed so as to be able to contact the end surface 331. The cylindrical portion 504 is disposed between the end surface 40a of the movable core 40 and the plate portion 503b. In the present embodiment, the housing recess 45 and the recess 451 shown in FIG. 9 are eliminated. The cylindrical portion 504 is sandwiched between the movable core 40 and the disc portion 503 by the elastic force of the first spring 80. The outer peripheral surface of the cylindrical portion 504 is positioned in the radial direction by the inner wall 63 of the fixed core 60. That is, the cylindrical portion 504 is slidable in the axial direction along the inner wall 63 of the fixed core 60.

The collar portion 33 is disposed inside the cylindrical portion 504. The inner peripheral surface of the cylindrical portion 504 is slidable in the axial direction with respect to the outer peripheral surface of the flange portion 33.

10, a gap is formed between the lower end surface 332 of the flange portion 33 and the end surface 40a of the movable core 40. The axial distance of this gap corresponds to the distance G1 shown in FIG. 2, and various dimensions are set so as to satisfy the relationship of G1 <G2 and G1 = L2-L1 as in FIG. .

Also in this embodiment, similarly to the second embodiment, the needle 30B is guided to the inner wall 63 of the fixed core 60 via the moving member. Therefore, it is advantageous to improve the coaxiality of the fixed core 60, the moving member, and the needle 30B. For this reason, in the reciprocating movement of the needle 30B in the axial direction, the needle 30B can be prevented from being inclined in the radial direction. Therefore, the stability of the reciprocating movement of the needle 30B in the axial direction can be enhanced.

(Fourth embodiment)
In the process of FIG. 8 according to the first embodiment, when it is determined that the overshoot amount L3 is equal to or greater than the predetermined amount Lth, all of the plurality of first target values I1 set for different supply fuel pressures Pf are included. The reduction correction is performed for this. On the other hand, in the present embodiment, the first target value I1 corresponding to the supply fuel pressure Pf that is equal to or higher than the predetermined pressure is prohibited from being corrected for reduction. For example, when the fuel is injected at the first target value I1 corresponding to 5 MPa, and the overshoot amount L3 is equal to or greater than the predetermined amount Lth, the first target value I1 corresponding to 5 MPa and 10 MPa is reduced and corrected. On the other hand, the reduction correction is prohibited for the first target value I1 corresponding to 20 MPa which is equal to or higher than the predetermined pressure.

The present inventors have found that overshoot is more likely to occur as the supply fuel pressure Pf is lower. In the present embodiment in view of this knowledge, the target value setting unit 114 prohibits a decrease (that is, a reduction correction) of the target value for the first target value I1 corresponding to the supply fuel pressure Pf equal to or higher than the predetermined pressure. Therefore, when the supply fuel pressure Pf is high and the required valve opening force Fa is large, the electromagnetic attraction force does not decrease due to the reduction correction of the first target value I1, so that the electromagnetic attraction force exceeds the required valve opening force Fa. The certainty of rising can be improved.

(Fifth embodiment)
In the first embodiment, when it is determined in step S12 of FIG. 8 that the overshoot amount L3 is equal to or greater than the predetermined amount Lth, in the next step S13, a plurality of second set fuel fuel pressures Pf are set. Reduction correction is performed on all the target values I1. On the other hand, in the present embodiment, the first target value I1 corresponding to the supply fuel pressure Pf used for setting the first target value I1 in step S10 in FIG. 8 is reduced and corrected to correspond to other supply fuel pressures Pf. For the first target value I1, the reduction correction is not performed. That is, among the plurality of first target values I1 for each supply fuel pressure Pf, the first target value I1 in which the overshoot amount L3 actually becomes excessive is set as the target of reduction correction, and the other first target values I1 are reduced. Not subject to correction.

(Other embodiments)
Although the preferred embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made as illustrated below. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

In the embodiment shown in FIG. 1, the fuel pressure supplied to the fuel injection valve 1 is detected by the fuel pressure sensor 200, and the overshoot is based on the detected pressure waveform, that is, the waveform of the pressure change caused by fuel injection from the injection hole 11. The amount L3 is estimated. On the other hand, the speed when the movable core 40 collides with the fixed core 60 may be detected, and the overshoot amount L3 may be estimated based on the detected speed. There is a correlation between the collision speed of the movable core 40 and the overshoot amount L3. Since the overshoot amount L3 increases as the collision speed increases, the overshoot amount can be estimated by detecting the collision speed as described above. The collision speed can be calculated based on the elapsed time by detecting the elapsed time from the energization start time to the coil 70 to the collision time of the movable core 40 to the fixed core 60.

As the movable core 40 collides with the fixed core 60 and stops moving, the waveform of the coil current is disturbed. The time when this disturbance appears may be regarded as the collision time. Alternatively, a switch circuit that switches the energization on / off state when the movable core 40 collides with the fixed core 60 is mounted on the fuel injection valve 1, and the switching timing of the energization state of the switch circuit may be regarded as the collision timing.

In the reduction correction according to the first embodiment, in step S13 of FIG. 8, all of the plurality of first target values I1 set for different supply fuel pressures Pf are uniformly reduced by a predetermined amount. On the other hand, you may vary the correction amount which carries out reduction correction according to supply fuel pressure Pf. For example, the correction amount may be decreased as the first target value I1 corresponding to the higher supply fuel pressure Pf.

In each of the above embodiments, the core boost type fuel injection valve 1 in which the needle 30 starts the valve opening operation after the movable core 40 moves by a predetermined amount is applied as a control target of the fuel injection control device. On the other hand, a normal type fuel injection valve in which the needle starts the valve opening operation simultaneously with the start of the movement of the movable core 40 may be applied as a control target of the fuel injection control device.

The means and / or function provided by the ECU 100 (control device) can be provided by software recorded in a substantial storage medium and a computer that executes the software, only software, only hardware, or a combination thereof. For example, if the controller is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a number of logic circuits, or an analog circuit.

Claims

With respect to the fixed core (60) that generates an electromagnetic attraction force when energized to the coil (70), the movable core (40) that is attracted and moved by the fixed core (60), and the movable core (40) And a valve body (30, 30B) that is assembled in a relatively movable state and engages with the movable core (40) that moves to open the nozzle (11). In the fuel injection control device applied to the fuel injection valve (1, 1A, 1B) for injecting fuel from
When the valve body (30, 30B) is in a closed state, the coil current (70) is started to increase, and the coil (70) is supplied with electric power so as to increase the coil current to a target value. A rise control unit (111) for controlling the supply;
A target value setting unit (114) for setting the target value;
As a result of increasing the coil current to the target value, the valve body (30, 30B) continues to move with inertia even after the movable core (40) moves and contacts the fixed core (60). An estimation unit (115) for estimating an overshoot amount of the valve body (30, 30B) when an overshoot behavior appears;
With
When the overshoot amount estimated by the estimation unit (115) is equal to or greater than a predetermined amount, the target value setting unit (114) lowers the target value compared to the current setting in the subsequent settings. A fuel injection control device.
A fuel pressure acquisition unit (116) for acquiring a supply fuel pressure that is a pressure of fuel supplied to the fuel injection valve (1, 1A, 1B);
The target value setting unit (114)
While setting the target value according to the acquired supply fuel pressure,
2. The fuel injection control according to claim 1, wherein among the target values for each of the supply fuel pressures, at least the target value corresponding to the supply fuel pressure when the overshoot amount is equal to or greater than a predetermined amount is decreased. apparatus.
The fuel injection control device according to claim 2, wherein the target value setting unit (114) prohibits a decrease in the target value for the target value corresponding to the supply fuel pressure equal to or higher than a predetermined pressure.
After the movable core (40) is sucked by the fixed core (60) and moved by a predetermined amount, the movable core (40) engages with the valve body (30, 30B) to start the valve opening operation. The fuel injection control device according to any one of claims 1 to 3, wherein the fuel injection control device is applied to the fuel injection valve (1, 1A, 1B) having a structure.
With respect to the fixed core (60) that generates an electromagnetic attraction force when energized to the coil (70), the movable core (40) that is attracted and moved by the fixed core (60), and the movable core (40) And a valve body (30, 30B) that is assembled in a relatively movable state and engages with the movable core (40) that moves to open the nozzle (11). Fuel injection valves (1, 1A, 1B) for injecting fuel from
A fuel injection control device (100) for controlling the operation of the fuel injection valve (1, 1A, 1B) by controlling a coil current flowing through the coil (70);
A fuel injection system comprising:
The fuel injection control device (100)
When the valve body (30, 30B) is in a closed state, the coil current (70) is started to increase, and the coil (70) is supplied with electric power so as to increase the coil current to a target value. A rise control unit (111) for controlling the supply;
As a result of increasing the coil current to the target value, the valve body (30, 30B) continues to move with inertia even after the movable core (40) moves and contacts the fixed core (60). An estimation unit (115) for estimating an overshoot amount of the valve body (30, 30B) when an overshoot behavior appears;
A target value setting unit (114) for setting the target value so as to decrease the target value to be used next time when the overshoot amount estimated by the estimation unit (115) is a predetermined amount or more; ,
A fuel injection system comprising:
In the fuel injection valve (1, 1A, 1B), after the movable core (40) is sucked by the fixed core (60) and moved by a predetermined amount, the movable core (40) is moved to the valve body (30, 30B). The fuel injection system according to claim 5, wherein the valve opening operation is started by engaging with ().