JP2001349257A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a needle valve up to an intermediate lift position without increasing force for energizing the needle valve to the valve opening side, and to almost stop the needle valve in the position without balancing force for energizing the needle valve to the valve opening side with force for energizing the needle valve to the valve closing side. SOLUTION: The sum of hydraulic pressure in a pressure control chamber 4 for energizing the needle valve 2 to the valve closing side at closing time of a pressure control valve 5 and spring force of a spring 8 is set larger than hydraulic pressure in a fuel reserving chamber 3 for energizing the needle valve 2 to the valve opening side, and the sum of the hydraulic pressure in the pressure control chamber 4 for energizing the needle valve 2 to the valve closing side at valve opening time of the pressure control valve 5 and the spring force of the spring 8 is set smaller than the hydraulic pressure in the fuel reserving chamber 3 for energizing the needle valve 2 to the valve opening side, and a valve opening state and a valve closing state of the pressure control valve 5 are continuously changed over at a short time interval, and the needle valve 2 is almost stopped in an optional lift position between a fully opening position and a fully closing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fuel injection valve.

[0002]

2. Description of the Related Art Conventionally, an injection hole opening / closing valve for opening / closing a fuel injection injection hole, valve opening side urging means for urging the injection hole opening / closing valve to the valve opening side, and an injection hole opening / closing valve for closing the injection hole opening / closing valve. 2. Description of the Related Art There is known a fuel injection valve including a valve-closing-side urging means for urging. An example of this type of fuel injection valve is described in, for example, Japanese Patent Application Laid-Open No. Hei 9-144567. In the fuel injection valve described in JP-A-9-144567, the valve-opening-side urging means is formed by a fuel reservoir, and the valve-closing-side urging means is constituted by a spring.

[0003]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No.
In the fuel injection valve described in Japanese Patent No. 144567, since the valve closing-side urging means is constituted by a spring, the injection hole opening / closing valve is moved from the fully closed position to the intermediate lift position between the fully open position and the fully closed position. In order to move, the pressure in the fuel accumulation chamber is increased, that is, the fuel supply pressure is increased, and the force for urging the injection hole opening / closing valve toward the valve opening side urges the injection hole opening / closing valve toward the valve closing side. It must be greater than the force. Also, in order to almost stop the injection hole opening / closing valve at the intermediate lift position, the pressure in the fuel reservoir is adjusted, and the force for urging the injection hole opening / closing valve to the valve opening side and the injection hole opening / closing valve to the valve closing side are adjusted. You must balance the biasing force. In addition, in order to substantially stop the injection hole opening / closing valve at an arbitrary intermediate lift position, the force for urging the injection hole opening / closing valve to the valve opening side at each intermediate lift position and the injection hole opening / closing valve to the valve closing side are applied. The pressure in the fuel sump chamber must be fine-tuned to balance the forces.

In view of the above problems, the present invention can move an injection hole opening / closing valve from a fully closed position to an intermediate lift position without increasing the force for urging the injection hole opening / closing valve toward the valve opening side. The nozzle opening / closing valve can be almost stopped at the intermediate lift position without the need to balance the force urging the nozzle opening / closing valve to the valve opening side and the force urging the nozzle opening / closing valve to the valve closing side, It is another object of the present invention to provide a fuel injection valve capable of substantially stopping an injection hole opening / closing valve at an arbitrary intermediate lift position without having to finely adjust a force for urging the injection hole opening / closing valve toward the valve opening side.

[0005]

According to the first aspect of the present invention, an injection hole opening / closing valve that opens and closes a fuel injection injection hole, and a valve opening side that urges the injection hole opening / closing valve toward the valve opening side. A fuel injection valve comprising: a biasing unit; and a valve closing-side biasing unit that biases the injection hole opening / closing valve toward a valve closing side. A pressure control valve for controlling the pressure in the control chamber is provided, and when the pressure control valve is closed, a force for urging the nozzle hole opening / closing valve to the valve closing side opens the nozzle hole opening valve. And the force for urging the nozzle opening / closing valve to the valve closing side when the pressure control valve is opened urges the nozzle hole opening / closing valve to the valve opening side. And the pressure control valve is continuously switched between a valve open state and a valve closed state at short time intervals, whereby the fully open position is obtained. The injection hole shutoff valve the fuel injection valve to which nearly to stop the is provided at any lift position between the fully closed position.

In the fuel injection valve according to the first aspect, the valve closing-side urging means is formed by the pressure control chamber, and the pressure in the pressure control chamber is controlled by the pressure control valve. Therefore, by increasing or decreasing the pressure in the pressure control chamber, it is possible to increase or decrease the force for urging the nozzle hole opening / closing valve to the valve closing side. By reducing, the injection hole opening / closing valve can be moved from the fully closed position to the intermediate lift position without increasing the force for urging the injection hole opening / closing valve to the valve opening side. Further, in the fuel injection valve according to the first aspect, an opening state of the pressure control valve in which a force for urging the injection hole opening / closing valve toward the valve closing side is smaller than a force for urging the injection hole opening / closing valve toward the valve opening side. By continuously switching the pressure control valve to a closed state in which the force for urging the nozzle opening / closing valve toward the valve closing side is greater than the force for biasing the nozzle hole opening / closing valve to the valve opening side at short time intervals, The injection hole opening / closing valve is almost stopped at the intermediate lift position. Therefore, the injection hole opening / closing valve can be almost stopped at the intermediate lift position without having to balance the force urging the injection hole opening / closing valve to the valve opening side and the force urging the injection hole opening / closing valve to the valve closing side. . In addition, by changing the switching timing of the pressure control valve between the open state and the closed state, the injection hole opening / closing valve can be arbitrarily adjusted without fine adjustment of the force for urging the injection hole opening / closing valve toward the valve opening side. It can be almost stopped at the intermediate lift position.

According to the second aspect of the present invention, the lift amount of the injection hole opening / closing valve is detected, and the opening / closing switching timing of the pressure control valve is determined based on the detected lift amount of the injection hole opening / closing valve. A fuel injection valve according to claim 1 is provided.

In the fuel injection valve according to the second aspect, the switching timing of the pressure control valve is determined based on the detected lift amount of the injection hole opening / closing valve. Therefore, compared to the case where the lift amount of the injection hole opening / closing valve is predicted without actually being detected, and the opening / closing switching timing of the pressure control valve is determined based on the predicted lift amount of the injection hole opening / closing valve, the injection hole opening / closing timing is determined. The valve can be positioned exactly at the desired intermediate lift position.

According to the third aspect of the present invention, when the injection hole opening / closing valve is moving to the valve opening side and the lift amount of the injection hole opening / closing valve becomes equal to or more than a first value, the pressure increases. The control valve is switched from the open state to the closed state, and the pressure control is performed when the injection hole opening / closing valve is moving to the valve closing side and the lift amount of the injection hole opening / closing valve becomes a second value or less. A fuel injection valve according to claim 2, wherein the valve is switched from a closed state to an open state.

In the fuel injection valve according to the third aspect, when the injection hole opening / closing valve is moving to the valve opening side and the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value, the pressure control valve is activated. The valve is switched from the open state to the closed state. That is, the pressure control valve is not switched from the open state to the closed state only when the lift amount of the injection hole opening / closing valve is equal to or more than the first value, and the injection hole opening / closing valve is moving to the valve opening side. The pressure control valve is switched from the open state to the closed state when the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value. Therefore, the pressure control valve is switched from the open state to the closed state when the lift amount of the injection hole opening / closing valve is equal to or more than the first value but the injection hole opening / closing valve is moving to the valve closing side. As a result, it is possible to prevent the injection hole opening / closing valve from being completely closed. Further, in the fuel injection valve according to the third aspect, the pressure control valve is closed when the injection hole opening / closing valve is moving to the valve closing side and the lift amount of the injection hole opening / closing valve becomes a second value or less. The state is switched from the state to the valve open state. That is, the pressure control valve is not switched from the closed state to the open state only when the lift amount of the injection hole opening / closing valve becomes equal to or less than the second value, and the injection hole opening / closing valve is moving to the valve closing side. When the lift amount of the injection hole opening / closing valve becomes equal to or less than the second value, the pressure control valve is switched from the closed state to the open state. Therefore, the pressure control valve is switched from the closed state to the open state when the lift amount of the injection hole opening / closing valve is less than or equal to the second value but the injection hole opening / closing valve is moving to the valve opening side. As a result, it is possible to prevent the injection hole opening / closing valve from being fully opened.

According to the fourth aspect of the present invention, when the injection hole opening / closing valve is moved from the fully closed position to an intermediate lift position between the fully opened position and the fully closed position to substantially stop, At the first time when the injection hole opening / closing valve moves to the valve opening side, when the lift amount of the injection hole opening / closing valve becomes a third value or more, the pressure control valve is switched from the open state to the closed state. In the second and subsequent times when the injection hole opening / closing valve moves to the valve opening side, the pressure control valve is closed from the open state when the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value. 4. The fuel injection valve according to claim 3, wherein the state is switched to a valve state, and the third value is set to a value smaller than the first value.

In the fuel injection valve according to the fourth aspect, when the injection hole opening / closing valve is moved from the fully closed position to the intermediate lift position and substantially stopped, the injection hole opening / closing valve moves to the valve opening side. At the first time, when the lift amount of the injection hole opening / closing valve becomes equal to or more than a third value smaller than the first value, the pressure control valve is switched from the open state to the closed state, and the injection hole opening / closing valve is closed. In the second and subsequent movements toward the valve opening side, the pressure control valve is switched from the open state to the closed state when the lift amount of the injection hole opening / closing valve becomes equal to or greater than the first value. Therefore, at the first time when the acceleration at which the injection hole opening / closing valve moves to the valve opening side is large, the pressure control valve is changed from the open state to the closed state until the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value. It is possible to prevent the lift amount of the injection hole opening / closing valve from overshooting due to the inability to switch to the above.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view of a first embodiment of the fuel injection valve of the present invention. In FIG. 1, reference numeral 1 denotes a fuel injection injection hole, 2 denotes a needle valve for opening and closing the fuel injection injection hole 1, 3
Numeral 4 denotes a fuel reservoir for urging the needle valve 2 toward the valve opening side (upper side in FIG. 1), and numeral 4 denotes a pressure control chamber for urging the needle valve 2 toward the valve closing side (lower side in FIG. 1). 5 is a pressure control valve for controlling the pressure in the pressure control chamber 4, 6 is a piezoelectric actuator for driving the pressure control valve 5, and 7 is a pressure control valve 5.
And a piezo-type actuator 6. Specifically, the fuel not injected from the fuel injection nozzle 1 is used as the hydraulic oil 6. Reference numeral 8 denotes a spring for urging the needle valve 2 toward the valve closing side (the lower side in FIG. 1), 9 denotes a permanent magnet, and 10 denotes an electromagnetic coil. When the lift amount of the needle valve 2 changes and the distance between the upper end of the needle valve 2 and the permanent magnet 9 changes, the magnetic flux changes and the electromagnetic coil 10
Current flows through By detecting the current flowing through the electromagnetic coil 10, it is possible to grasp the lift amount of the needle valve 2 and whether the needle valve 2 is moving to the valve opening side or the valve closing side. In the present embodiment, the needle valve 2
Although the permanent magnet 9 and the electromagnetic coil 10 are used as the means for detecting the lift amount and the moving direction of the motor, a known position sensor can be used in other embodiments.

As shown in FIG. 1, in the fuel injection valve of the present embodiment, when the pressure control valve 5 is fully opened, the pressure control chamber for urging the needle valve 2 to the valve closing side (the lower side in FIG. 1). The sum of the oil pressure (fuel pressure) in the fuel tank 4 and the spring pressure of the spring 8 becomes smaller than the oil pressure in the fuel pool 3 that urges the needle valve 2 toward the valve opening side (upper side in FIG. 1). , The needle valve 2 is moved to the valve opening side. On the other hand, the pressure control valve 5
When the needle valve 2 is fully closed, the sum of the oil pressure (fuel pressure) in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (downward in FIG. 1) and the spring pressure of the spring 8 indicates that the needle valve 2 Becomes larger than the oil pressure in the fuel pool chamber 3 that urges the needle valve 2 toward the valve opening side (upper side in FIG. 1). As a result, the needle valve 2 is moved to the valve closing side. Therefore, if the pressure control valve 5 continues to be fully opened, the needle valve 2 is fully opened. That is, the needle valve 2 is located at the maximum lift position (lift amount = Lmax). On the other hand, if the pressure control valve 5 continues to be fully closed, the needle valve 2 is fully closed (lift amount = 0). Further, in the present embodiment, the needle valve 2 is continuously switched between the state in which the pressure control valve 5 is fully opened and the state in which the pressure control valve 5 is fully closed so that the needle valve 2 is not fully opened or fully closed, so that the needle valve 2 is moved to the intermediate lift position. Almost stopped.

FIG. 2 shows the behavior of the pressure control valve when the needle valve is almost stopped at the intermediate lift position, and the relationship between the pressure in the pressure control chamber and the lift amount of the needle valve. It is the figure which expanded and showed a part. As shown in FIGS. 2 and 3, before time t1, the pressure control valve 5
Has been fully closed, as a result, the pressure in the pressure control chamber 4 has reached the maximum Pmax, and the needle valve 2 is fully closed (lift amount = 0). Next, at time t1, when an instruction to fully open the pressure control valve 5 is issued to position the needle valve 2 at the intermediate lift position, the piezo actuator 6 is extended and the pressure control valve 5 is fully opened. At this time, the pressure in the pressure control chamber 4 starts to decrease, but the pressure in the pressure control chamber 4 that urges the needle valve 2 to the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 still remain. Is larger than the oil pressure in the fuel pool 3, which urges the needle valve 2 toward the valve opening side (upper side in FIG. 1), and the needle valve 2 is fully closed (lift amount = 0). .

At time t2, the pressure in the pressure control chamber 4 becomes the minimum Pmin, and as a result, the hydraulic pressure in the pressure control chamber 4 for urging the needle valve 2 to the valve closing side (the lower side in FIG. 1). The sum with the spring pressure of the spring 8 becomes smaller than the oil pressure in the fuel pool 3 that urges the needle valve 2 toward the valve opening side (upper side in FIG. 1), and the needle valve 2 starts to move toward the valve opening side. .
After an instruction to move the needle valve 2 to the intermediate lift position is issued at time t1, when the lift amount of the needle valve 2 first becomes equal to or more than the predetermined lift amount L3 (time t3), the pressure control valve 5 is fully closed. An instruction is issued, and accordingly, the piezoelectric actuator 6 contracts and the pressure control valve 5 is fully closed. As a result, the pressure in the pressure control chamber 4 increases again, and the sum of the oil pressure in the pressure control chamber 4 that urges the needle valve 2 toward the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 is increased. Then, the pressure becomes higher than the oil pressure in the fuel accumulation chamber 3 for urging the needle valve 2 toward the valve opening side (upper side in FIG. 1). Therefore, the needle valve 2 is prevented from being fully opened, and the needle valve 2 is almost stopped at the intermediate lift position.

In this state, the sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to move toward the valve opening side. Since the pressure is higher than the oil pressure in the fuel accumulation chamber 3 (upper side in FIG. 1), the needle valve 2 starts to move to the valve closing side again after a while. When the lift amount of the needle valve 2 becomes equal to or less than the predetermined lift amount L1 (time t4), the pressure control valve 5
Is issued, the piezo actuator 6 is extended, and the pressure control valve 5 is fully opened. As a result, the pressure in the pressure control chamber 4 decreases again,
The sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (lower side in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to move toward the valve opening side (upper side in FIG. 1). It becomes smaller than the hydraulic pressure in the fuel pool 3 to be energized. Therefore, the needle valve 2 is prevented from being fully closed, and the needle valve 2 is almost stopped at the intermediate lift position.

In this state, the sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to move toward the valve opening side. Since it is smaller than the oil pressure in the fuel accumulation chamber 3 urged upward (upper side in FIG. 1), the needle valve 2 starts moving to the valve opening side again after a while. When the lift amount of the needle valve 2 exceeds the predetermined lift amount L2 (time t5), the pressure control valve 5
Is issued, the piezo actuator 6 contracts, and the pressure control valve 5 is fully closed. As a result, the pressure in the pressure control chamber 4 increases again,
The sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (lower side in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to move toward the valve opening side (upper side in FIG. 1). It becomes larger than the hydraulic pressure in the fuel pool 3 to be energized. Therefore, the needle valve 2 is prevented from being fully opened, and the needle valve 2 is almost stopped at the intermediate lift position.

Similarly, in this state, the sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (downward in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to open. The pressure is higher than the oil pressure in the fuel pool 3 that urges the valve 2 (upper side in FIG. 1).
Starts moving to the valve closing side again. When the lift amount of the needle valve 2 becomes equal to or less than the predetermined lift amount L1 (time t6), an instruction to fully open the pressure control valve 5 is issued.
The piezo actuator 6 is extended, and the pressure control valve 5 is fully opened. As a result, the pressure in the pressure control chamber 4 decreases again, and the sum of the oil pressure in the pressure control chamber 4 that urges the needle valve 2 toward the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 is increased. Then, the pressure becomes lower than the oil pressure in the fuel accumulation chamber 3 which urges the needle valve 2 toward the valve opening side (upper side in FIG. 1). Therefore, the needle valve 2 is prevented from being fully closed, and the needle valve 2 is almost stopped at the intermediate lift position.

Similarly, in this state, the sum of the oil pressure in the pressure control chamber 4 for urging the needle valve 2 toward the valve closing side (downward in FIG. 1) and the spring pressure of the spring 8 causes the needle valve 2 to open. Since it is smaller than the oil pressure in the fuel pool 3 that urges the valve side (upper side in FIG. 1), the needle valve 2
Starts moving to the valve opening side again. When the lift amount of the needle valve 2 becomes equal to or more than the predetermined lift amount L2 (time t7), an instruction to fully close the pressure control valve 5 is issued.
The piezo actuator 6 contracts, and the pressure control valve 5 is fully closed. As a result, the pressure in the pressure control chamber 4 increases again, and the sum of the oil pressure in the pressure control chamber 4 that urges the needle valve 2 toward the valve closing side (the lower side in FIG. 1) and the spring pressure of the spring 8 is increased. Then, the pressure becomes higher than the oil pressure in the fuel accumulation chamber 3 for urging the needle valve 2 toward the valve opening side (upper side in FIG. 1). Therefore, the needle valve 2 is prevented from being fully opened, and the needle valve 2 is almost stopped at the intermediate lift position.

As described above, while the instruction for positioning the needle valve 2 at the intermediate lift position is issued (time t2 to time t2).
At time t11), the pressure control valve 5 is continuously switched between the fully open state and the fully closed state at short time intervals. Then, at time t1
When an instruction to fully close the pressure control valve 5 is issued to 1 to fully close the needle valve 2, the piezo actuator 6 contracts and the pressure control valve 5 is fully closed. As a result, the pressure in the pressure control chamber 4 increases again, and the needle valve 2
The sum of the oil pressure in the pressure control chamber 4 and the spring pressure of the spring 8 urges the needle valve 2 toward the valve opening side (upper side in FIG. 1). It becomes larger than the oil pressure in the fuel pool 3. Therefore, the needle valve 2 is fully closed.

In the example shown in FIGS. 2 and 3, the needle valve 2
Is switched from fully closed to intermediate lift position to fully closed. In other examples, the needle valve 2 is switched from fully closed to intermediate lift position to fully open, or the needle valve 2 is fully opened to intermediate lift position to fully open. Or the needle valve 2 can be switched from fully open to intermediate lift position to fully closed.

FIG. 4 is a flowchart showing a control method of the pressure control valve for substantially stopping the needle valve at the intermediate lift position in the present embodiment. As shown in FIG. 4, when this routine is started, first, Step 100
In, it is determined whether there is an instruction to continue fuel injection. When the determination is NO, that is, when the needle valve 2 is to be fully closed, the process proceeds to step 101, and in step 101, the pressure control valve 5 is fully closed. On the other hand, if YES, that is, if the needle valve 2 should be almost stopped at the intermediate lift position, the routine proceeds to step 102. Step 10
In 2, it is determined whether or not the needle valve 2 is moving to the valve opening side. When the determination is NO, that is, when the needle valve 2 is moving to the valve closing side, or when the needle valve 2 is fully closed, the process proceeds to step 103. On the other hand, if YES, the process proceeds to step 105.

In step 103, it is determined whether the lift amount L of the needle valve 2 is equal to or less than a threshold value L1. NO
In this case, the state of the pressure control valve 5 is maintained as it is, and this routine ends. On the other hand, if YES, the process proceeds to step 104, where the pressure control valve 5
Is fully opened. That is, when the needle valve 2 is moving to the valve closing side and the lift amount L of the needle valve 2 is equal to or less than the threshold value L1 (at times t4, t6, t8, and t8 in FIGS. 2 and 3).
t10) or when the needle valve 2 is fully closed and the lift amount L of the needle valve 2 is less than or equal to the threshold L1 (time t1 to time t2 in FIGS. 2 and 3), the pressure control valve 5 Is fully opened.

In step 105, after an instruction to position the needle valve 2 at the intermediate lift position is issued, it is determined whether or not the needle valve 2 moves to the valve opening side for the first time. If YES, proceed to step 106, NO
In other words, if the instruction to move the needle valve 2 to the intermediate lift position is issued after the needle valve 2 moves to the valve opening side for the second time or later, the process proceeds to step 107. In step 106, the lift amount L of the needle valve 2 is
Is greater than or equal to a threshold L3. When the determination is YES, the process proceeds to step 101, where the pressure control valve 5 is completely closed. That is, when the needle valve 2 is moving to the valve opening side for the first time and the lift amount L of the needle valve 2 becomes equal to or greater than the threshold value L3 (time t3 in FIGS. 2 and 3), the pressure control valve 5 is fully closed. Can be On the other hand, N
In the case of O, the state of the pressure control valve 5 is maintained as it is, and this routine ends. That is, although the needle valve 2 is moving to the valve opening side for the first time, the lift amount L of the needle valve 2 is
Is less than the threshold value L3 (time t2 to time t3 in FIGS. 2 and 3), the pressure control valve 5 is kept fully open.

In step 107, it is determined whether or not the lift amount L of the needle valve 2 is equal to or greater than a threshold value L2. YE
In the case of S, the process proceeds to step 108, in which the pressure control valve 5 is fully closed. That is, when the needle valve 2 moves to the valve opening side and the needle valve 2 moves to the valve opening side for the second time or later and the lift amount L of the needle valve 2 becomes equal to or larger than the threshold value L2 (see FIG. 2 and FIG.
(Time t5, t7, t9), the pressure control valve 5 is fully closed. On the other hand, when the determination is NO, the state of the pressure control valve 5 is maintained as it is, and this routine ends. That is, when the needle valve 2 has moved to the valve opening side and the needle valve 2 has moved to the valve opening side for the second time or later, but the lift amount L of the needle valve 2 is less than the threshold value L2, the pressure control valve 5 remains fully open.

According to the present embodiment, the needle valve 2 is urged toward the valve closing side by the pressure in the pressure control chamber 4, and the pressure in the pressure control chamber 4 is controlled by the pressure control valve 5. Therefore, by increasing or decreasing the pressure in the pressure control chamber 4, the force for urging the needle valve 2 toward the valve closing side can be increased or decreased. Therefore, the force for urging the needle valve 2 toward the valve closing side can be reduced. By decreasing the needle valve 2, the needle valve 2 can be moved from the fully closed position to the intermediate lift position without increasing the pressure in the fuel pool 3 that urges the needle valve 2 toward the valve opening side. Further, the pressure control valve 5 is opened (particularly fully open) in which the force for urging the needle valve 2 toward the valve closing side is smaller than the force for urging the needle valve 2 toward the valve opening side. Is continuously switched at short time intervals between the closed state (particularly the fully closed state) of the pressure control valve 5 in which the force for urging the needle valve 2 toward the valve closing side is greater than the force for urging the needle valve 2 toward the valve opening side. As a result, the needle valve 2 is almost stopped at the intermediate lift position. Therefore, the needle valve 2 can be almost stopped at the intermediate lift position without having to balance the force urging the needle valve 2 to the valve opening side and the force urging the needle valve 2 to the valve closing side. In addition, by changing the switching timing of the pressure control valve 5 between the open state and the closed state, the needle valve 2 can be moved to any intermediate position without having to finely adjust the force for urging the needle valve 2 to the open side. It can be almost stopped at the lift position. Specifically, the lift amount at the intermediate lift position can be increased by increasing the threshold value L3 (FIGS. 2 and 3) and delaying the pressure control valve 5 from being fully closed. Conversely, by decreasing the threshold value L3 (FIGS. 2 and 3) and hastening the pressure control valve 5 to be fully closed,
The lift amount at the intermediate lift position can be reduced.

According to the present embodiment, step 10
3. Needle valve 2 detected by permanent magnet 9 and electromagnetic coil 10 in steps 106 and 107
The opening / closing switching timing of the pressure control valve 5 is determined based on the lift amount. That is, control for positioning the needle valve 2 at the intermediate lift position is performed by feedback control.
Therefore, compared to the case of the predictive control in which the lift amount of the needle valve 2 is predicted without actually detecting and the opening / closing switching timing of the pressure control valve 5 is determined based on the predicted lift amount of the needle valve 2, The valve 2 can be positioned exactly at the desired intermediate lift position.

Further, according to the present embodiment, when the lift amount L of the needle valve 2 becomes greater than or equal to the threshold L2 while the needle valve 2 is moving to the valve opening side, the pressure control valve 5 is opened in step 108. The state is switched from the valve state to the valve closed state.
That is, the pressure control valve 5 is not switched from the open state to the closed state only when the lift amount L of the needle valve 2 becomes equal to or larger than the threshold value L2 (before time t5 ′, before time t7 ′, and at time t9 in FIG. 3). 'Before), the pressure control valve 5 is switched from the open state to the closed state when the lift amount L of the needle valve 2 becomes greater than or equal to the threshold L2 while the needle valve 2 is moving to the valve opening side (FIG. 2 and time t5, time t7, and time t9 in FIG. 3). Therefore, the lift amount L of the needle valve 2 is
The pressure control valve 5 is closed from the open state when the needle valve 2 is moving to the valve closing side (before time t5 ', before time t7', and before time t9 'in FIG. 3). It is possible to prevent the needle valve 2 from being completely closed by being switched to the valve state.

Further, according to this embodiment, when the needle valve 2 is moving to the valve closing side and the lift amount L of the needle valve 2 becomes equal to or less than the threshold value L1, the pressure control valve 5 is closed in step 104. The state is switched from the valve state to the valve open state.
That is, the pressure control valve 5 is not switched from the closed state to the open state only when the lift amount L of the needle valve 2 becomes equal to or less than the threshold value L1 (before time t4 ′, before time t6 ′, and at time t8 in FIG. 3). 'Before, before time t10'), the needle valve 2 is moving to the valve closing side, and the lift amount L of the needle valve 2 is
Is lower than the threshold value L1, the pressure control valve 5 is switched from the closed state to the open state (time t in FIGS. 2 and 3).
4, time t6, time t8, time t10). Therefore, when the lift amount L of the needle valve 2 is less than or equal to the threshold L1, but the needle valve 2 is moving to the valve opening side (before time t4 ', before time t6', before time t8 'in FIG. 3, Time t
10 ′ (before 10 ′), the pressure control valve 5 is switched from the closed state to the open state and the needle valve 2 can be prevented from being fully opened.

Further, according to the present embodiment, when the needle valve 2 is moved from the fully closed position to the intermediate lift position to substantially stop, the first time the needle valve 2 moves to the valve opening side, When it is determined in step 106 that the lift amount L of the needle valve 2 has become equal to or greater than the threshold value L3 smaller than the threshold value L2, in step 101, the pressure control valve 5 is switched from the open state to the closed state. At the second and subsequent times when the valve 2 moves to the valve opening side, when it is determined in step 107 that the lift amount L of the needle valve 2 has become equal to or greater than the threshold value L2, the pressure control valve 5 is opened in step 108. Is switched to the closed state. Therefore, at the first time when the acceleration at which the needle valve 2 moves to the valve opening side is large, the pressure control valve 5 switches from the open state to the closed state until the lift amount L of the needle valve 2 becomes equal to or greater than the threshold L2. As a result, the lift amount of the needle valve 2 can be prevented from overshooting and becoming much larger than the lift amount of the required intermediate lift (FIG. 3).

Hereinafter, a second embodiment of the fuel injection valve of the present invention will be described. The configuration of the fuel injection valve of the present embodiment is the same as the configuration of the fuel injection valve of the first embodiment shown in FIG. FIG. 5 is a flowchart showing a control method of the pressure control valve for substantially stopping the needle valve at the intermediate lift position in the present embodiment. As shown in FIG. 5, when this routine is started, first, in step 200, it is determined whether or not there is an instruction to continue fuel injection as in step 100 of FIG. When the determination is NO, the process proceeds to step 201, where the pressure control valve 5 is fully closed as in step 101 of FIG. On the other hand, if YES, the process proceeds to step 202. In step 202, it is determined whether or not the needle valve 2 is moving to the valve opening side as in step 102 in FIG. If NO, the process proceeds to step 203, and if YES, the process proceeds to step 207.

In step 203, step 10 in FIG.
Similarly to 3, it is determined whether the lift amount L of the needle valve 2 is equal to or less than the threshold value L1. If NO, the pressure control valve 5
Is maintained as it is, and this routine ends.
On the other hand, if YES, the process proceeds to step 204, where the pressure control valve 5 is fully opened as in step 104 of FIG. In step 207, similarly to step 107 in FIG. 4, the lift amount L of the needle valve 2 is
Is greater than or equal to a threshold L2. If YES, the process proceeds to step 201, where the pressure control valve 5 is fully closed in step 201. On the other hand, when the determination is NO, the state of the pressure control valve 5 is maintained as it is, and this routine ends. That is, in the present embodiment, the needle valve 2
Regardless of whether or not the valve moves to the valve opening side for the first time, when the lift amount L of the needle valve 2 is equal to or larger than the threshold value L2, the pressure control valve 5 is fully closed in step 201, while the needle When the lift amount L of the valve 2 is less than the threshold value L2, the state of the pressure control valve 5 is maintained as it is.

According to the present embodiment, step 10 in FIG.
By eliminating Step 5 and Step 106, the control method of the pressure control valve can be simplified as compared with the case of the first embodiment. Further, according to the present embodiment, substantially the same effects as those of the first embodiment can be obtained except for the effect of providing Steps 105 and 106 in FIG.

[0036]

According to the first aspect of the present invention, by increasing or decreasing the pressure in the pressure control chamber, it is possible to increase or decrease the force for urging the nozzle opening / closing valve toward the valve closing side.
By reducing the force that urges the injection hole opening / closing valve toward the valve closing side, the injection hole opening / closing valve can be moved from the fully closed position to the intermediate lift position without having to increase the force that urges the injection hole opening / closing valve toward the valve opening side. Can be moved. Further, the injection hole opening / closing valve can be almost stopped at the intermediate lift position without having to balance the force for urging the injection hole opening / closing valve to the valve opening side and the force urging the injection hole opening / closing valve to the valve closing side. . In addition, by changing the switching timing of the pressure control valve between the open state and the closed state, the injection hole opening / closing valve can be arbitrarily adjusted without fine adjustment of the force for urging the injection hole opening / closing valve toward the valve opening side. It can be almost stopped at the intermediate lift position.

According to the second aspect of the invention, the lift amount of the injection hole opening / closing valve is predicted without actually detecting it, and the pressure control valve is opened / closed based on the predicted lift amount of the injection hole opening / closing valve. As compared with the case where the switching timing is determined, the injection hole opening / closing valve can be accurately positioned at the desired intermediate lift position.

According to the third aspect of the present invention, when the lift amount of the injection hole opening / closing valve is equal to or more than the first value, but the injection hole opening / closing valve is moving to the valve closing side, the pressure control valve Can be switched from the open state to the closed state, and the injection hole opening / closing valve can be prevented from being fully closed. Further, the pressure control valve is switched from the closed state to the open state when the lift amount of the injection hole opening / closing valve is less than or equal to the second value but the injection hole opening / closing valve is moving to the valve opening side. As a result, it is possible to prevent the injection hole opening / closing valve from being fully opened.

According to the fourth aspect of the present invention, the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value at the first time when the acceleration at which the injection hole opening / closing valve moves to the valve opening side is large. Until the pressure control valve cannot be switched from the open state to the closed state, it is possible to prevent the lift amount of the injection hole opening / closing valve from overshooting.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a first embodiment of a fuel injection valve of the present invention.

FIG. 2 is a diagram showing the behavior of the pressure control valve when the needle valve is almost stopped at an intermediate lift position, and the relationship between the pressure in the pressure control chamber and the lift amount of the needle valve.

FIG. 3 is an enlarged view of a part of FIG. 2;

FIG. 4 is a flowchart showing a control method of a pressure control valve for substantially stopping a needle valve at an intermediate lift position in the first embodiment.

FIG. 5 is a flowchart showing a control method of a pressure control valve for substantially stopping a needle valve at an intermediate lift position in a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Injection hole for fuel injection 2 ... Needle valve 3 ... Fuel reservoir 4 ... Pressure control chamber 5 ... Pressure control valve 6 ... Piezo actuator 7 ... Hydraulic oil 8 ... Spring 9 ... Permanent magnet 10 ... Electromagnetic coil

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA07 AB02 AC09 AD12 BA01 CC06T CC08T CC14 CC26 CC64U CC67 CC68T CD25 CD26 CE13 CE27 CE35 DC06

Claims (4)

[Claims] 1. An injection hole opening / closing valve for opening / closing a fuel injection injection hole, valve opening side urging means for urging the injection hole opening / closing valve to an opening side, and the injection hole opening / closing valve to a valve closing side. A valve closing side biasing means for biasing, the valve closing side biasing means is formed by a pressure control chamber, provided with a pressure control valve for controlling the pressure in the pressure control chamber, When the pressure control valve is closed, the force for urging the nozzle hole opening / closing valve to the valve closing side is greater than the force for urging the nozzle hole opening / closing valve to the valve opening side, and the pressure control is performed. When the valve is opened, the force for urging the nozzle opening / closing valve to the valve closing side is made smaller than the force for urging the nozzle hole opening / closing valve to the valve opening side, and the pressure control valve is opened. By continuously switching between the valve state and the valve closed state at short time intervals, the nozzle hole is opened at an arbitrary lift position between the fully open position and the fully closed position. A fuel injection valve whose valve closing is almost stopped. 2. The apparatus according to claim 1, wherein a lift amount of the injection hole opening / closing valve is detected, and an opening / closing switching timing of the pressure control valve is determined based on the detected lift amount of the injection hole opening / closing valve. Fuel injection valve. 3. The pressure control valve is closed from an open state when the injection hole opening / closing valve is moving to the valve opening side and the lift amount of the injection hole opening / closing valve is equal to or more than a first value. The pressure control valve is switched from the closed state to the open state when the injection hole opening / closing valve is moving to the valve closing side and the lift amount of the injection hole opening / closing valve becomes a second value or less. 3. The fuel injection valve according to claim 2, wherein the fuel injection valve is switched over. 4. When the injection hole opening / closing valve is moved from a fully closed position to an intermediate lift position between a fully opened position and a fully closed position to substantially stop, the injection hole opening / closing valve is moved to the valve opening side. At the time of the first movement, the pressure control valve is switched from the open state to the closed state when the lift amount of the injection hole opening / closing valve becomes equal to or more than a third value, and the injection hole opening / closing valve is opened. Side, the pressure control valve is switched from the open state to the closed state when the lift amount of the injection hole opening / closing valve becomes equal to or more than the first value, and the third The fuel injection valve according to claim 3, wherein the value is set to a value smaller than the first value.