JP2002070684A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly open and close a needle valve. SOLUTION: This fuel injection device comprises the needle valve 2 for opening and closing a nozzle hole 1, pressure control chambers 3 and 6 for energizing the needle valve 1 to the opening side and a fuel basin chamber 4 for energizing the needle valve 2 to the opening side. A pressure control valve 10 for controlling the presser in the pressure control chambers 3 and 6 is arranged within a pressure control valve chamber 40, and the pressure control chamber 3 and 6 are allowed to communicate with the pressure control valve chamber 40 through communicating passages 31 and 33 having restriction parts 31' and 33'. A communicating passage 34 is arranged between a high-pressure fuel supplying passage 20 and the chamber 40, and the fuel flow rate supplied to the chamber 40 through the passage 34 is increased to quickly carry the fuel supplied through the passage 34 during the opening period of the pressure control valve into the pressure control chambers 3 and 6. The inflow of the fuel supplied through the passage 34 to the pressure control chambers 3 and 6 through the passages 31 and 33 during the opening period of the pressure control valve 10 is prevented by the restriction parts 31' and 33', and the fuel in the pressure control chamber 3 and 6 is quickly carried through the passages 31 and 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, an injection hole opening / closing valve for opening / closing a fuel injection injection hole, a valve closing-side biasing means for urging the injection hole opening / closing valve to a valve closing side, and an injection hole opening / closing valve for opening a valve. Valve-opening biasing means for biasing, the valve-closing-side biasing means has a pressure control chamber, a pressure control valve for controlling the pressure in the pressure control chamber is disposed in the pressure control valve chamber, The pressure control chamber and the pressure control valve chamber communicate with each other by the first series passage having the throttle portion, and during the valve opening period of the pressure control valve, the fuel in the pressure control chamber is provided with the first series passage having the throttle portion and 2. Description of the Related Art There is known a fuel injection device that is discharged into a low-pressure fuel leak passage via a pressure control valve chamber. Examples of this type of fuel injection device include, for example, WO 97/48
In FIG. 3, FIG. 5, FIG. No. 6 is described. In the fuel injection device described in WO97 / 48900, the injection hole opening / closing valve is opened by reducing the pressure in the pressure control chamber during the opening period of the pressure control valve, and the valve closing period of the pressure control valve is closed. The nozzle opening / closing valve is closed by increasing the pressure in the pressure control chamber. Further, in the fuel injection device described in WO97 / 48900, the pressure control chamber and the pressure control valve chamber are communicated with each other by the first series passage having the throttle portion. The flow rate of the fuel flowing out of the pressure control chamber is determined by the throttle. As a result, the fuel flow rate flowing out of the pressure control chamber can be made equal to a desired fuel flow rate without accurately controlling the opening amount of the pressure control valve.

[0003]

However, WO97 /
In the fuel injection device described in Japanese Patent No. 48900, although a passage for supplying fuel into the pressure control chamber is disposed between the high-pressure fuel supply passage and the pressure control chamber, the high-pressure fuel supply passage and the pressure control It is not located between the valve chamber. That is, in the fuel injection device described in WO97 / 48900, fuel is not supplied from the high-pressure fuel supply passage into the pressure control chamber via the first passage provided with the pressure control valve chamber and the throttle portion. Is supplied directly from the high-pressure fuel supply passage into the pressure control chamber. Therefore, even if an attempt is made to decrease the pressure in the pressure control chamber in order to open the injection hole opening / closing valve, the fuel in the pressure control chamber is continuously supplied from the high-pressure fuel supply passage to the pressure control chamber. Can not be reduced.

Therefore, in order to quickly reduce the pressure in the pressure control chamber and quickly open the injection hole opening / closing valve, it is conceivable to set the flow rate of fuel supplied from the high-pressure fuel supply passage to a relatively small flow rate. Can be However, in such a case, it takes a relatively long time to increase the pressure in the pressure control chamber during the closing period of the pressure control valve, and the injection hole opening / closing valve is quickly closed. Can not do. On the other hand, in order to quickly increase the pressure in the pressure control chamber during the closing period of the pressure control valve and quickly close the injection hole opening / closing valve,
When the flow rate of the fuel supplied from the high-pressure fuel supply passage is set to a relatively high flow rate, for a reason described above, it takes a relatively long time to reduce the pressure in the pressure control chamber during the opening period of the pressure control valve. Therefore, the injection hole opening / closing valve cannot be quickly opened. That is, WO97 / 4890
In the fuel injection device described in Japanese Patent Publication No. 0, the fuel is supplied directly from the high-pressure fuel supply passage into the pressure control chamber, so that the injection hole opening / closing valve can be quickly opened while the injection hole opening / closing valve is quickly closed. I can't make it valveable.

[0005] In view of the above problems, an object of the present invention is to provide a fuel injection device in which the injection hole opening / closing valve can be quickly closed while the injection hole opening / closing valve can be quickly opened. .

[0006]

According to the first aspect of the present invention, an injection hole opening / closing valve for opening and closing a fuel injection injection hole, and a valve closing side for urging the injection hole opening / closing valve to a valve closing side. Biasing means, and valve-opening-side biasing means for biasing the nozzle opening / closing valve to the valve-opening side, wherein the valve-closing-side biasing means has a pressure control chamber, and a pressure in the pressure control chamber. A pressure control valve for controlling the pressure control valve chamber is disposed in the pressure control valve chamber, and the pressure control chamber and the pressure control valve chamber are communicated with each other by a first series passage having a throttle portion, and a valve opening period of the pressure control valve In the fuel injection device, the fuel in the pressure control chamber is discharged into a low-pressure fuel leak passage through a first series passage including the throttle portion and the pressure control valve chamber. A second communication passage for supplying fuel to the chamber is disposed between the high-pressure fuel supply passage and the pressure control valve chamber. Fuel injection device is provided.

According to the second aspect of the present invention, during the opening period of the pressure control valve, the flow of the fuel supplied through the second communication passage into the pressure control chamber is restricted by the throttle section. The fuel gas in the pressure control chamber is facilitated to be discharged into the low-pressure fuel leak passage through the first series passage including the throttle portion and the pressure control valve chamber by suppressing the pressure. 3. A fuel injection device according to (1) is provided.

In the fuel injection device according to the first and second aspects, the second communication passage for supplying fuel into the pressure control chamber is disposed between the high-pressure fuel supply passage and the pressure control valve chamber.
Therefore, by setting the flow rate of fuel supplied from the high-pressure fuel supply passage to the pressure control valve chamber via the second communication passage to a relatively large flow rate, the pressure control valve chamber is closed during the valve closing period. The supplied fuel quickly flows into the pressure control chamber through the first communication passage. Therefore, it is possible to quickly increase the pressure in the pressure control chamber and quickly close the injection hole opening / closing valve. On the other hand, during the opening period of the pressure control valve, the fuel supplied from the high pressure fuel supply passage to the pressure control valve chamber via the second communication passage is filled in the gap between the pressure control valve chamber and the low pressure fuel leak passage. Is sufficiently large, the pressure in the pressure control valve chamber becomes lower than the pressure in the pressure control chamber, so that the fuel is discharged into the low-pressure fuel leak passage without flowing into the pressure control chamber. As a result, the fuel in the pressure control chamber is promoted to be discharged into the low-pressure fuel leak passage through the first series passage and the pressure control valve chamber, and the fuel in the pressure control chamber is quickly discharged from the pressure control chamber. . Therefore, it is possible to quickly reduce the pressure in the pressure control chamber and quickly open the injection hole opening / closing valve. That is, the injection hole on-off valve can be quickly closed while the injection hole on-off valve can be quickly opened.

According to the third aspect of the present invention, there is provided a maximum lift amount adjusting means for adjusting a maximum lift amount which is a lift amount when the injection hole opening / closing valve is fully opened, and the maximum lift amount is provided on the side where the maximum lift amount is increased. While dividing the pressure control chamber into a first pressure control chamber that urges the maximum lift amount adjustment means, and a second pressure control chamber that urges the maximum lift amount adjustment means to the side that reduces the maximum lift amount, The first series passage is divided into a first pressure control chamber communication passage and a second pressure control chamber communication passage, and the relationship between the pressure in the first pressure control chamber and the pressure in the second pressure control chamber is changed. The fuel injection device according to claim 1, wherein the maximum lift amount is changed by doing so.

In the fuel injection device according to the third aspect, the pressure in the first pressure control chamber for urging the maximum lift adjustment means to increase the maximum lift, and the maximum lift to decrease the maximum lift. By changing the relationship with the pressure in the second pressure control chamber that activates the amount adjusting means, the maximum lift amount when the injection hole opening / closing valve is fully opened can be changed. That is,
In order to change the maximum lift amount, the relationship between the pressure in the first pressure control chamber and the pressure in the second pressure control chamber only needs to be changed, and it is not necessary to change the pressure in the high-pressure fuel supply passage.
Since the object to be changed to change the maximum lift amount is the pressure in the first pressure control chamber and the pressure in the second pressure control chamber, the maximum lift amount is changed by changing the extension amount of the piezo actuator, for example. As in the case, the maximum lift amount does not change with the temperature change.
Therefore, it is possible to change the maximum lift amount when the injection hole on-off valve is fully opened without changing the pressure in the high pressure fuel supply passage, and even when the temperature is changed, the maximum lift amount when the injection hole on-off valve is fully opened is changed. The maximum lift can be accurately controlled.

According to the fourth aspect of the present invention, the first mode in which the pressure in the first pressure control chamber is increased while the pressure in the first pressure control chamber is increased, and the pressure in the first pressure control chamber is increased. A second mode in which the pressure in the second pressure control chamber is reduced and a third mode in which the pressure in the second pressure control chamber is increased while decreasing the pressure in the first pressure control chamber. A fuel injection device according to claim 3 provided in a control valve is provided.

In the fuel injection device according to the fourth aspect, the first mode in which the pressure in the first pressure control chamber is increased while the pressure in the second pressure control chamber is increased, and the pressure in the first pressure control chamber is decreased. Since the pressure control valve has a second mode in which the pressure in the second pressure control chamber is reduced and a third mode in which the pressure in the first pressure control chamber is reduced and the pressure in the second pressure control chamber is increased, the pressure is reduced. Switching the control valve mode to fully close the orifice on / off valve, increasing the maximum lift to fully open the orifice on / off valve, and reducing the maximum lift to fully open the orifice on / off valve It is possible to switch between the squeeze state.

According to the fifth aspect of the invention, the fuel injection according to the third aspect, wherein the passage for allowing the fuel to flow into the first pressure control chamber is constituted only by the communication path for the first pressure control chamber. An apparatus is provided.

In the fuel injection device according to the fifth aspect, the passage through which the fuel flows into the first pressure control chamber is constituted only by the communication passage for the first pressure control chamber. Therefore, it is possible to eliminate the necessity of machining a passage that directly connects the high-pressure fuel supply passage and the first pressure control chamber, and it is possible to reduce the cost of the fuel injection device. Further, the pressure in the first pressure control chamber can be reduced more quickly than when a passage that directly connects the high-pressure fuel supply passage and the first pressure control chamber is provided.

According to the sixth aspect of the present invention, the fuel injection according to the third aspect, wherein the passage for allowing the fuel to flow into the second pressure control chamber is constituted only by the communication path for the second pressure control chamber. An apparatus is provided.

In the fuel injection device according to the sixth aspect, the passage through which the fuel flows into the second pressure control chamber is constituted only by the communication passage for the second pressure control chamber. Therefore, it is possible to eliminate the necessity of processing a passage that directly connects the high-pressure fuel supply passage and the second pressure control chamber, and it is possible to reduce the cost of the fuel injection device. Further, the pressure in the second pressure control chamber can be reduced more quickly than when a passage that directly connects the high-pressure fuel supply passage and the second pressure control chamber is provided.

[0017]

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

FIG. 1 is an overall configuration diagram of a first embodiment of a fuel injection device of the present invention, and FIG. 2 is an enlarged view of FIG. 1 and 2, reference numeral 1 denotes an injection hole for fuel injection, 2 denotes a needle valve for opening and closing the injection hole 1 for fuel injection, 2a denotes a command piston disposed above the needle valve 2, and 3 denotes a needle valve and a command valve. The first pressure control chamber 4 for urging the piston 2a to the valve closing side is a fuel pool chamber for urging the needle valve 2 and the command piston 2a to the valve opening side. 5 is a needle valve 2
Is a lift lock piston for adjusting a maximum lift amount, which is a lift amount when fully opened. That is, the position of the needle valve 2 when the command piston 2a is abutted against the lift lock piston 5 located at the predetermined position is the maximum lift position. The lift lock piston 5 is urged to increase the maximum lift by the pressure in the first pressure control chamber 3 and is urged to decrease the maximum lift by the pressure in the second pressure control chamber 6. .

Reference numeral 7 denotes a cylinder for guiding the lift lock piston 5, and this cylinder 7 is a first cylinder member 7a.
And the second cylinder member 7b. When the pressure in the first pressure control chamber 3 is lower than the pressure in the second pressure control chamber 6, the lift lock piston 5 is urged downward,
It is moved downward until it hits the lower abutment surface 7c. On the other hand, when the pressure in the first pressure control chamber 3 is higher than the pressure in the second pressure control chamber 6, the lift lock piston 5
Is urged upward and moved upward until it abuts against the upper abutment surface 7d. 10 is a pressure control valve for adjusting the pressure in the first pressure control chamber 3 and the second pressure control chamber 6, 10 a is a rod-shaped member constituting the pressure control valve 10,
b is a spherical member constituting the pressure control valve 10, and 40 is a pressure control valve chamber surrounding the pressure control valve 10. Reference numeral 11 denotes a piezo actuator for driving the pressure control valve 10, and 12 denotes a pressure control valve 10 and the piezo actuator 1
1 is an intermediate hydraulic chamber, and 13 is a needle valve 2
Is biased toward the valve closing side.

Reference numeral 20 denotes a high-pressure fuel supply passage through which high-pressure fuel (hydraulic oil) flows, and reference numerals 21 and 22 denote low-pressure fuel leak passages through which lower-pressure fuel flows than in the high-pressure fuel supply passage 20.
In the high-pressure fuel supply passage 20, fuel at a constant pressure is supplied from a common rail (not shown). Reference numeral 30 denotes a first pressure control chamber inlet passage through which fuel flows into the first pressure control chamber 3. A throttle portion 30 ′ is formed in the first pressure control chamber inlet passage 30. Reference numeral 31 denotes a first pressure control chamber communication passage that connects the first pressure control chamber 3 and the pressure control valve chamber 40. A throttle portion 31 'is also formed in the first pressure control chamber communication passage 31. Reference numeral 32 denotes a second pressure control chamber inlet passage through which fuel flows into the second pressure control chamber 6. A throttle portion 32 'is also formed in the first pressure control chamber inlet passage 32. Reference numeral 33 denotes a second pressure control chamber communication passage that communicates the second pressure control chamber 6 with the pressure control valve chamber 40. A throttle portion 33 'is also formed in the second pressure control chamber communication passage 33. 34 is a high-pressure fuel supply passage 20 and a pressure control valve chamber 4
This is a third communication path that directly communicates with a zero. Third communication passage 34
Also, a throttle portion 34 'is formed. 50 is a member in which the third communication passage 34 is formed, and 51 is a member in which the second pressure control chamber inlet passage 32 is formed.

FIG. 3 is a diagram showing operation states of the pressure control valve 10 for comparison. More specifically, FIG. 3A shows a first state in which the outflow of fuel from the first pressure control chamber 3 and the outflow of fuel from the second pressure control chamber 6 are both interrupted.
FIG. 3B shows a second state in which both the outflow of fuel from the first pressure control chamber 3 and the outflow of fuel from the second pressure control chamber 6 are not interrupted, and FIG. 3C shows the first pressure. FIG. 9 is a diagram illustrating a third state in which the outflow of fuel from the control chamber 3 is not interrupted and the outflow of fuel from the second pressure control chamber 6 is interrupted.
As shown in FIG. 3A, in the first state, the fuel flowing out of the pressure control valve chamber 40 into the low-pressure fuel leak passage 21 is blocked by the rod-shaped member 10 a of the pressure control valve 10. As a result, the fuel in the first pressure control chamber 3 cannot flow out of the first pressure control chamber 3, and similarly, the fuel in the second pressure control chamber 6 cannot flow out of the second pressure control chamber 6.
As shown in FIG. 3B, in the second state, the fuel flowing out of the pressure control valve chamber 40 into the low-pressure fuel leak passage 21 is not blocked by the rod-shaped member 10 a of the pressure control valve 10. The fuel flowing from the second pressure control chamber 6 into the pressure control valve chamber 40 is also caused by the spherical member 10 of the pressure control valve 10.
Not blocked by b. As a result, the first pressure control chamber 3
The fuel inside can flow out of the first pressure control chamber 3,
Similarly, the fuel in the second pressure control chamber 6 is
Can be spilled from. As shown in FIG.
In the third state, the flow of fuel from the pressure control valve chamber 40 into the low-pressure fuel leak passage 21 is not blocked by the rod-shaped member 10a of the pressure control valve 10, but the fuel flows from the second pressure control chamber 6 to the pressure control valve chamber 40. The flow of fuel into the inside is blocked by the spherical member 10b of the pressure control valve 10. As a result, the fuel in the first pressure control chamber 3
However, the fuel in the second pressure control chamber 6 cannot flow out of the second pressure control chamber 6.

FIG. 4 is a diagram showing the operation of the lift lock piston 5 in comparison. 4A shows a state where the lift lock piston 5 is abutted against the lower abutting surface 7c, and FIG. 4B shows a state where the lift lock piston 5 abuts against the upper abutting surface 7d. FIG. 4C is a bottom view of the lift lock piston 5, showing a state in which the lift lock piston 5 is applied. In FIG. 4, 5 a prevents the top surface of the command piston 2 a, which is abutted against the bottom surface of the lift lock piston 5, from sticking to the bottom surface of the lift lock piston 5. This is a separation promoting groove for promoting the separation of the top surface of the command piston 2a from the bottom surface of the piston 5. 5b is a separation promoting hole formed for the same purpose as the separation promoting groove 5a.

As shown in FIGS. 1 to 4, when the fuel injection is to be started, specifically, when the fuel is to be injected with a small maximum lift amount, the piezo actuator 11 is extended and the pressure control is performed. The valve 10 is arranged in the third state (FIG. 3C). In the third state, fuel flows out of the first pressure control chamber 3. As a result, the first pressure control chamber 3
The combined force of the force in which the fuel inside urges the needle valve 2 toward the valve closing side and the force with which the spring 13 urges the needle valve 2 toward the valve closing side is:
The fuel in the fuel pool 4 becomes smaller than the force urging the needle valve 2 toward the valve-opening side, so that the needle valve 2 is opened. In the third state, the outflow of fuel from the second pressure control chamber 6 is shut off. As a result, the pressure in the second pressure control chamber 6 becomes higher than the pressure in the first pressure control chamber 3, so that the lift lock piston 5 is abutted against the lower abutment surface 7c and has a small maximum lift. The amount is defined (FIG. 4 (a)). That is, the needle valve 2 and the command piston 2a are abutted against the lift lock piston 5 arranged in the state of FIG. 4A, and fuel injection is performed.

Next, when fuel is to be injected with a large maximum lift, the piezo actuator 11 is slightly contracted, and the pressure control valve 10 is placed in the second state (FIG. 3B). In the second state, as in the third state described above, fuel is allowed to flow out of the first pressure control chamber 3, and as a result, the fuel in the first pressure control chamber 3 urges the needle valve 2 toward the valve closing side. The combined force of the force and the force of the spring 13 urging the needle valve 2 toward the valve closing side is smaller than the force of the fuel in the fuel accumulation chamber 4 urging the needle valve 2 toward the valve opening side. Thus, the open state of the needle valve 2 is maintained as it is. Further, in this second state, the fuel in the second pressure control chamber 6 also flows out of the second pressure control chamber 6, so that the pressure in the second pressure control chamber 6 also decreases to the same level as the pressure in the first pressure control chamber 3. Therefore, not only the needle valve 2 and the command piston 2a but also the lift lock piston 5 are urged upward by the pressure in the fuel pool chamber 4, and the needle valve 2, The command piston 2a and the lift lock piston 5 are both moved upward. That is, the maximum lift amount is increased by the stroke amount t (FIG. 4B) of the lift lock piston 5 from that shown in FIG. 4A, and fuel injection is performed under the large maximum lift amount. .

Next, when fuel injection is to be stopped, the piezo actuator 11 is further contracted, and the pressure control valve 10 is placed in the first state (FIG. 3A). In this first state, the outflow of fuel from the first pressure control chamber 3 and the second pressure control chamber 6 to the low pressure fuel leak passage 21 is shut off. As a result, the combined force of the force that urges the fuel in the first pressure control chamber 3 toward the valve closing side of the needle valve 2 and the force that the spring 13 urges the needle valve 2 toward the valve closing side is equal to the fuel accumulation chamber. The fuel in 4 becomes larger than the force for urging the needle valve 2 to the valve opening side, so that the needle valve 2 is closed. Further, when the state is switched from the second state to the first state, the first pressure control chamber 6 is configured to increase the pressure in the second pressure control chamber 6 earlier than in the first pressure control chamber 3. 3 and the throttle portion 30 ', and the second pressure control chamber 6 and the throttle portion 32' are formed. Specifically, the volume of the second pressure control chamber 6 is smaller than the volume of the first pressure control chamber 3. As a result, in order to perform fuel injection with a small maximum lift amount at the start of the next fuel injection, the lift lock piston 5
By the end of the current fuel injection, the fuel is moved downward so as to abut against the lower abutting surface 7c (FIG. 4A).

As shown in FIGS. 2 to 4, in the present embodiment, the high-pressure fuel supply passage 20 and the pressure control valve chamber 40 are connected by a third communication passage 34. Therefore, in the first state of the pressure control valve 10 (FIG. 3A), not only is the fuel supplied to the first pressure control chamber 3 via the first pressure control chamber inlet passage 30, but also the Fuel is supplied through the three communication passages 34 and the first pressure control chamber communication passage 31. Further, the fuel is supplied to the second pressure control chamber 6 not only through the second pressure control chamber inlet passage 32 but also through the third communication passage 34 and the second pressure control chamber communication passage 33. Fuel is supplied. Therefore, by setting the flow rate of fuel supplied from the high-pressure fuel supply passage 20 to the pressure control valve chamber 40 via the third communication passage 34 to a relatively large flow rate, the pressure control valve 10 is closed during the valve closing period (FIG. 3). (A)) The pressure control valve chamber 40
Is quickly flowed into the first pressure control chamber 3 via the first pressure control chamber communication path 31 and the second pressure control chamber is supplied via the second pressure control chamber communication path 33. 6 quickly flows into. Therefore, the pressure in the first pressure control chamber 3 and the pressure in the second pressure control chamber 6 can be rapidly increased, and the needle valve 2 can be quickly closed.

On the other hand, during the valve opening period of the pressure control valve 10 under the second state (FIG. 3B), the high pressure fuel supply passage 20
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And the flow into the second pressure control chamber 6 through the second pressure control chamber communication passage 33 is suppressed by the throttle portion 33 ′, and the first pressure control chamber 3 and the second Low pressure fuel leak passage 2 without flowing into pressure control chamber 6
It is discharged into 1. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31 and the pressure control valve chamber 40.
And the fuel in the second pressure control chamber 6 is discharged through the second pressure control chamber communication passage 33 and the pressure control valve chamber 40. The discharge into the leak passage 21 is promoted. Therefore, the fuel in the first pressure control chamber 3 is
From the second pressure control chamber 6
The fuel inside is quickly discharged from the second pressure control chamber 6. Therefore, the first pressure control chamber 3 and the second pressure control chamber 6
The internal pressure can be rapidly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a large maximum lift position.

During the opening period of the pressure control valve 10 under the third state (FIG. 3C), the high-pressure fuel supply passage 20 is opened.
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And is discharged into the low-pressure fuel leak passage 21 without flowing into the first pressure control chamber 3. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31.
And the low pressure fuel leak passage 21 through the pressure control valve chamber 40
It is promoted to be discharged into. Therefore, the fuel in the first pressure control chamber 3 is quickly discharged from the first pressure control chamber 3. Therefore, the pressure in the first pressure control chamber 3 can be quickly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a small maximum lift position.

That is, according to the present embodiment, the needle valve 2
Can be quickly opened and the needle valve 2 can be quickly closed.

More specifically, first, in the case of the fuel injection device of the present embodiment provided with the pressure control valve 10, the pressure control valve 1
During the zero valve opening period, the flow rate of the fuel flowing out of the first pressure control chamber 3 is determined not by the opening amount of the pressure control valve 10 but by the throttle portion 31 ′ of the first pressure control chamber communication passage 31. Therefore, it is necessary to set the degree of aperture of the aperture section 31 'to a relatively strong value. Second, in the case of the fuel injection device of the present embodiment including the high-pressure fuel supply passage 20, it is necessary to inject fuel at low pressure near idle (low load side) in order to reduce combustion noise near idle. is there. When the pressure in the high-pressure fuel supply passage 20 is set to a relatively low value, the force in which the fuel in the first pressure control chamber 3 urges the needle valve 2 toward the valve closing side and the spring 13
Of the force for urging the needle valve 2 to the valve-closing side, and the force for urging the needle valve 2 to the valve-closing side. Account for a larger proportion. As a result, third, in order to quickly open the needle valve 2 by overcoming the force by which the spring 13 urges the needle valve 2 toward the valve closing side during the opening operation of the needle valve 2, At the time of the valve opening operation, that is, during the valve opening period of the pressure control valve 10, the ratio of the fuel flow rate flowing out of the first pressure control chamber 3 to the fuel flow rate flowing into the first pressure control chamber 3 is set to a considerably large value. Must be set.

On the other hand, as described above, it is necessary to set the degree of restricting of the restricting portion 31 ′ of the first pressure control chamber communication passage 31 to a relatively strong value. In order to set the ratio of the fuel flow rate flowing out of the pressure control chamber 3 to the fuel flow rate flowing into the first pressure control chamber 3 to a considerably large value, it is necessary to set the first pressure control valve 10 during the opening period of the pressure control valve 10. It is necessary to set the flow rate of the fuel flowing into the control chamber 3 to a considerably small value. Fourth, in order to quickly close the needle valve 2 during the closing operation of the needle valve 2, that is, during the closing period of the pressure control valve 10, the pressure control valve 10
It is necessary to set the flow rate of the fuel flowing into the first pressure control chamber 3 to a considerably large value during the valve closing period.

Based on these requirements, the fuel injection device of the present embodiment is configured as follows. First, based on the first requirement, the degree of restriction of the restrictor 31 ′ is relatively strong so that the opening of the restrictor 31 ′ of the first pressure control chamber communication passage 31 is smaller than the opening amount of the pressure control valve 10. Is set to a value. Next, based on the second requirement, the high-pressure fuel supply passage 2
The pressure within 0 is set to a relatively low value. Further, based on the third requirement, the throttle portion 3 of the first pressure control chamber inlet passage 30 is formed.
The aperture degree of 0 'is set to a relatively strong value. Alternatively, as in a fuel injection device according to a second embodiment described later, the first pressure control chamber inlet passage 30 is eliminated, and the pressure control valve 10
During the valve opening period, the flow rate of the fuel flowing into the first pressure control chamber 3 can be reduced to zero. Further, based on the fourth requirement, in order to increase the flow rate of fuel flowing into the first pressure control chamber 3 during the closing period of the pressure control valve 10, the high pressure fuel supply passage 20 and the third communication passage 34 and the pressure control The degree of throttle of the throttle portion 34 'of the third communication passage 34 is set to a relatively weak value so that the flow rate of fuel flowing into the first pressure control valve chamber 3 via the valve chamber 40 increases.

In this way, the needle valve 2 can be quickly closed while the needle valve 2 can be quickly opened.

According to the present embodiment, the pressure in the first pressure control chamber 3 for urging the lift lock piston 5 toward the side where the maximum lift is increased and the lift lock piston 5 toward the side where the maximum lift is reduced. Pressure control chamber 6 for energizing
By changing the relationship with the internal pressure by the piezo actuator 11, the maximum lift amount when the needle valve 2 is fully opened is changed. That is, in order to change the maximum lift, the relationship between the pressure in the first pressure control chamber 3 and the pressure in the second pressure control chamber 6 may be changed, and the pressure in the high-pressure fuel supply passage 20 may be changed. No need to do. Since the object to be changed to change the maximum lift amount is the pressure in the first pressure control chamber 3 and the pressure in the second pressure control chamber 6, the maximum lift amount is changed by changing the extension amount of the piezoelectric actuator. The maximum lift amount does not change with temperature change unlike the case of changing. Therefore, the maximum lift amount when the needle valve 2 is fully opened can be changed without having to change the pressure in the high-pressure fuel supply passage 20, and the maximum lift amount when the needle valve 2 is fully opened even when the temperature changes. The lift amount can be controlled accurately.

Further, according to the present embodiment, the first state (FIG. 3A) in which the pressure in the first pressure control chamber 3 is increased and the pressure in the second pressure control chamber 6 is increased, and The second state (FIG. 3B) in which the pressure in the pressure control chamber 3 is reduced and the pressure in the second pressure control chamber 6 is reduced, and the second state in which the pressure in the first pressure control chamber 3 is reduced. Since the pressure control valve 10 has a third state (FIG. 3 (c)) in which the pressure in the pressure control chamber 6 is increased, the state in which the needle valve 2 is fully closed by switching the state of the pressure control valve 10 is described. It is possible to switch between a state where the maximum lift is increased and the needle valve 2 is fully opened, and a state where the maximum lift is reduced and the needle valve 2 is fully opened.

FIG. 5 is an enlarged view similar to FIG. 2 of the second embodiment of the fuel injection device of the present invention. In FIG. 5, FIG.
The same reference numerals as those shown in FIGS.
2a ′ is a command piston arranged above the needle valve 2. FIG. That is, in the present embodiment, the first pressure control chamber inlet passage 30 and the throttle portion 3 of the first embodiment are used.
0 'has been excluded.

In the present embodiment, since the high-pressure fuel supply passage 20 and the pressure control valve chamber 40 are connected by the third communication passage 34, in the first state of the pressure control valve 10 (FIG. 3A), The fuel is supplied to the one pressure control chamber 3 via the third communication path 34 and the first pressure control chamber communication path 31.
Further, the fuel is supplied to the second pressure control chamber 6 not only through the second pressure control chamber inlet passage 32 but also through the third communication passage 34 and the second pressure control chamber communication passage 33. Fuel is supplied. Therefore, by setting the flow rate of fuel supplied from the high-pressure fuel supply passage 20 to the pressure control valve chamber 40 via the third communication passage 34 to a relatively large flow rate, the pressure control valve 10 is closed during the valve closing period (FIG. 3). (A)) The pressure control valve chamber 4
The fuel supplied to the first pressure control chamber 3 quickly flows into the first pressure control chamber 3 via the first pressure control chamber communication path 31, and the second pressure control via the second pressure control chamber communication path 33. It is quickly flowed into the chamber 6. Therefore, the pressure in the first pressure control chamber 3 and the pressure in the second pressure control chamber 6 can be rapidly increased, and the needle valve 2 can be quickly closed.

On the other hand, during the opening period of the pressure control valve 10 under the second state (FIG. 3B), the high-pressure fuel supply passage 20 is opened.
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And the flow into the second pressure control chamber 6 through the second pressure control chamber communication passage 33 is suppressed by the throttle portion 33 ′. Low pressure fuel leak passage 2 without flowing into pressure control chamber 6
It is discharged into 1. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31 and the pressure control valve chamber 40.
And the fuel in the second pressure control chamber 6 is discharged through the second pressure control chamber communication passage 33 and the pressure control valve chamber 40. The discharge into the leak passage 21 is promoted. Therefore, the fuel in the first pressure control chamber 3 is
From the second pressure control chamber 6
The fuel inside is quickly discharged from the second pressure control chamber 6. Therefore, the first pressure control chamber 3 and the second pressure control chamber 6
The internal pressure can be rapidly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a large maximum lift position.

During the opening period of the pressure control valve 10 under the third state (FIG. 3C), the high-pressure fuel supply passage 20 is opened.
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And is discharged into the low-pressure fuel leak passage 21 without flowing into the first pressure control chamber 3. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31.
And the low pressure fuel leak passage 21 through the pressure control valve chamber 40
It is promoted to be discharged into. Therefore, the fuel in the first pressure control chamber 3 is quickly discharged from the first pressure control chamber 3. Therefore, the pressure in the first pressure control chamber 3 can be quickly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a small maximum lift position.

That is, according to the present embodiment, the needle valve 2 can be quickly closed while the needle valve 2 can be quickly opened.

Further, according to the present embodiment, since the passage for the fuel to flow into the first pressure control chamber 3 is constituted only by the first pressure control chamber communication passage 31, the high pressure fuel supply passage 20 and the first It is possible to eliminate the necessity of machining a passage (the first pressure control chamber inlet passage 30 of the first embodiment) that directly communicates with the one pressure control chamber 3, and reduce the cost of the fuel injection device. it can. The high-pressure fuel supply passage 20
The pressure in the first pressure control chamber 3 is reduced more quickly than when a passage (the first pressure control chamber inlet passage 30 of the first embodiment) that directly communicates with the first pressure control chamber 3 is provided. Can be done.

FIG. 6 is an enlarged view similar to FIGS. 2 and 5 of the third embodiment of the fuel injection device of the present invention. In FIG. 6, the same reference numerals as those shown in FIGS. 1 to 5 indicate the same parts or parts as those shown in FIGS. Are formed. That is, in the present embodiment, the second pressure control chamber inlet passage 32 and the throttle portion 32 'of the second embodiment are eliminated.

In the present embodiment, since the high-pressure fuel supply passage 20 and the pressure control valve chamber 40 are communicated by the third communication passage 34, in the first state of the pressure control valve 10 (FIG. 3A) The fuel is supplied to the one pressure control chamber 3 via the third communication path 34 and the first pressure control chamber communication path 31.
Further, fuel is supplied to the second pressure control chamber 6 via the third communication path 34 and the second pressure control chamber communication path 33. Therefore, by setting the flow rate of fuel supplied from the high-pressure fuel supply passage 20 to the pressure control valve chamber 40 via the third communication passage 34 to a relatively large flow rate, the pressure control valve 10 is closed during the valve closing period (FIG. 3). In (a)), the fuel supplied to the pressure control valve chamber 40 is allowed to quickly flow into the first pressure control chamber 3 through the first pressure control chamber communication passage 31, and the fuel for the second pressure control chamber is used. The fluid is quickly flown into the second pressure control chamber 6 through the communication passage 33. Therefore, the pressure in the first pressure control chamber 3 and the pressure in the second pressure control chamber 6 can be rapidly increased, and the needle valve 2 can be quickly closed.

On the other hand, during the opening period of the pressure control valve 10 under the second state (FIG. 3B), the high pressure fuel supply passage 20
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And the flow into the second pressure control chamber 6 through the second pressure control chamber communication passage 33 is suppressed by the throttle portion 33 ′. Low pressure fuel leak passage 2 without flowing into pressure control chamber 6
It is discharged into 1. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31 and the pressure control valve chamber 40.
And the fuel in the second pressure control chamber 6 is discharged through the second pressure control chamber communication passage 33 and the pressure control valve chamber 40. The discharge into the leak passage 21 is promoted. Therefore, the fuel in the first pressure control chamber 3 is
From the second pressure control chamber 6
The fuel inside is quickly discharged from the second pressure control chamber 6. Therefore, the first pressure control chamber 3 and the second pressure control chamber 6
The internal pressure can be rapidly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a large maximum lift position.

During the opening period of the pressure control valve 10 under the third state (FIG. 3C), the high pressure fuel supply passage 20 is opened.
The fuel supplied to the pressure control valve chamber 40 through the third communication passage 34 through the third communication passage 34 flows into the first pressure control chamber 3 through the first pressure control chamber communication passage 31. And is discharged into the low-pressure fuel leak passage 21 without flowing into the first pressure control chamber 3. As a result, the fuel in the first pressure control chamber 3 is transferred to the first pressure control chamber communication passage 31.
And the low pressure fuel leak passage 21 through the pressure control valve chamber 40
It is promoted to be discharged into. Therefore, the fuel in the first pressure control chamber 3 is quickly discharged from the first pressure control chamber 3. Therefore, the pressure in the first pressure control chamber 3 can be quickly reduced, and the needle valve 2 can be quickly opened. In particular, the needle valve can be quickly moved to a small maximum lift position.

That is, according to the present embodiment, the needle valve 2 can be quickly closed while the needle valve 2 can be quickly opened.

Further, according to the present embodiment, since the passage for the fuel to flow into the second pressure control chamber 6 is constituted only by the second pressure control chamber communication passage 33, the high pressure fuel supply passage 20 and the second A passage that directly communicates with the second pressure control chamber 6 (the second pressure control chamber inlet passage 32 of the first and second embodiments).
Can be eliminated, and the cost of the fuel injection device can be reduced. Also, a passage that directly connects the high-pressure fuel supply passage 20 and the second pressure control chamber 6 (the second pressure control chamber inlet passage 3 of the first and second embodiments).
The pressure in the second pressure control chamber 6 can be reduced more quickly than in the case where 2) is provided.

The fuel injection device of the above embodiment has a lift lock piston 5, that is, a type having two pressure control chambers 3 and 6.
The present invention is also applicable to a fuel injection device having no lift lock piston, that is, having only one pressure control chamber.

[0049]

According to the first and second aspects of the present invention,
By setting the flow rate of the fuel supplied from the high-pressure fuel supply passage to the pressure control valve chamber via the second communication path to a relatively large flow rate, the fuel supply to the pressure control valve chamber is performed during the closing period of the pressure control valve. The fuel that has flowed into the pressure control chamber through the first series passage is quickly flown. Therefore, it is possible to quickly increase the pressure in the pressure control chamber and quickly close the injection hole opening / closing valve. On the other hand, during the opening period of the pressure control valve, the fuel supplied from the high-pressure fuel supply passage to the pressure control valve chamber via the second communication passage flows into the pressure control chamber via the first series passage. This is suppressed by the throttle portion, and is discharged into the low-pressure fuel leak passage without flowing into the pressure control chamber.
As a result, the fuel in the pressure control chamber is promoted to be discharged into the low-pressure fuel leak passage through the first series passage and the pressure control valve chamber, and the fuel in the pressure control chamber is quickly discharged from the pressure control chamber. . Therefore, it is possible to quickly reduce the pressure in the pressure control chamber and quickly open the injection hole opening / closing valve. That is, the injection hole on-off valve can be quickly closed while the injection hole on-off valve can be quickly opened.

According to the third aspect of the invention, it is possible to change the maximum lift amount when the injection hole opening / closing valve is fully opened without changing the pressure in the high-pressure fuel supply passage, and when the temperature changes. Even in this case, the maximum lift amount when the injection hole opening / closing valve is fully opened can be accurately controlled.

According to the fourth aspect of the present invention, the mode in which the mode of the pressure control valve is switched to completely close the injection hole opening / closing valve, and the state in which the maximum lift is increased to fully open the injection hole opening / closing valve. The state in which the maximum lift amount is reduced and the injection hole opening / closing valve is fully opened can be switched.

According to the fifth aspect of the present invention, it is possible to eliminate the necessity of machining a passage that directly connects the high-pressure fuel supply passage and the first pressure control chamber, thereby reducing the cost of the fuel injection device. be able to. Further, the pressure in the first pressure control chamber can be reduced more quickly than when a passage that directly connects the high-pressure fuel supply passage and the first pressure control chamber is provided.

According to the sixth aspect of the present invention, it is possible to eliminate the necessity of machining a passage that directly connects the high-pressure fuel supply passage and the second pressure control chamber, thereby reducing the cost of the fuel injection device. be able to. Further, the pressure in the second pressure control chamber can be reduced more quickly than when a passage that directly connects the high-pressure fuel supply passage and the second pressure control chamber is provided.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a first embodiment of a fuel injection device of the present invention.

FIG. 2 is an enlarged view of FIG.

FIG. 3 is a diagram comparing operation states of the pressure control valve 10;

FIG. 4 is a diagram comparing operation states of a lift lock piston 5;

FIG. 5 shows a second embodiment of the fuel injection device according to the present invention;
It is an enlarged view similar to.

FIG. 6 shows a third embodiment of the fuel injection device according to the present invention;
6 is an enlarged view similar to FIG. 5 and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Injection hole 2 ... Needle valve 3 ... First pressure control chamber 4 ... Fuel pool chamber 5 ... Lift lock piston 6 ... Second pressure control chamber 10 ... Pressure control valve 13 ... Spring 20 ... High pressure fuel supply passage 21 ... Low pressure fuel Leak passage 31 ... communication passage for first pressure control chamber 31 ', 33', 34 '... throttle section 33 ... communication passage for first pressure control chamber 34 ... third communication passage 40 ... pressure control valve chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA07 AC09 AD07 BA00 BA07 BA13 BA51 CC01 CC08T CC14 CC63 CE13 CE27 CE33 CE35 DA14 DA16 DC06

Claims (6)

[Claims] 1. An injection hole opening / closing valve for opening / closing a fuel injection injection hole, a valve closing-side biasing means for urging the injection hole opening / closing valve to a valve closing side, and the injection hole opening / closing valve to a valve opening side. Valve-side biasing means for biasing, the valve-closing side biasing means has a pressure control chamber,
A pressure control valve for controlling the pressure in the pressure control chamber is disposed in the pressure control valve chamber, and the pressure control chamber and the pressure control valve chamber are communicated with each other by a first series passage having a throttle portion.
During the opening period of the pressure control valve, the fuel in the pressure control chamber is discharged into the low pressure fuel leak passage via the first series passage including the throttle and the pressure control valve chamber. In the fuel injection device, a second communication passage for supplying fuel into the pressure control chamber is disposed between a high-pressure fuel supply passage and the pressure control valve chamber. 2. The valve according to claim 1, wherein the throttle section prevents fuel supplied through the second communication passage from flowing into the pressure control chamber during an opening period of the pressure control valve.
2. The fuel injection device according to claim 1, wherein the fuel in the pressure control chamber is facilitated to be discharged into the low-pressure fuel leak passage through the first series passage including the throttle portion and the pressure control valve chamber. 3. . 3. A maximum lift amount adjusting means for adjusting a maximum lift amount which is a lift amount when the injection hole opening / closing valve is fully opened, and the maximum lift amount adjusting means is urged to increase the maximum lift amount. The pressure control chamber is divided into a first pressure control chamber and a second pressure control chamber that urges the maximum lift adjustment means to the side where the maximum lift is reduced, and the first series passage has a first pressure control chamber. Dividing the communication passage for the control chamber and the communication passage for the second pressure control chamber, and changing the relationship between the pressure in the first pressure control chamber and the pressure in the second pressure control chamber to change the maximum lift amount 2. The fuel injection device according to claim 1, wherein: 4. A first mode for increasing the pressure in the first pressure control chamber and increasing the pressure in the second pressure control chamber, and reducing the pressure in the first pressure control chamber and controlling the second pressure control. 4. The pressure control valve according to claim 3, wherein the pressure control valve has a second mode for decreasing the pressure in the chamber and a third mode for decreasing the pressure in the first pressure control chamber and increasing the pressure in the second pressure control chamber. 5. Fuel injector. 5. The fuel injection device according to claim 3, wherein a passage through which fuel flows into the first pressure control chamber is constituted only by the first pressure control chamber communication passage. 6. The fuel injection device according to claim 3, wherein a passage for allowing fuel to flow into the second pressure control chamber is constituted only by the communication passage for the second pressure control chamber.