JP2000161176A - Piezoelectric control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric control valve facilitating temperature compensation and capable of stable fluid injection control. SOLUTION: When a valve element 40, a driving piezoelectric element 13, and a valve needle 15 are assembled to an injector body 5 so that the valve needle 15 makes contact with the valve element 40, a detecting piezoelectric element 16 detects the contact between the valve needle 15 and the valve element 40 to apply a bias voltage to the driving piezoelectric element 13 under at least either one of these conditions wherein the contact between the valve needle 15 and the valve element 40 cannot be maintained after assembly because of a difference in thermal expansion between the driving piezoelectric element 13 and the injector body 5 and wherein the contact between the valve needle 15 and the valve element 40 cannot be maintained because of changes with time. Therefore, the valve needle 15 can be held near the zero point of the valve element 40 and zero point correction and hence temperature compensation can be easily and surely performed. Thus, always stable fuel injection control can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric control valve, and more particularly, to a piezoelectric control valve suitable for a fuel injection device for intermittently injecting fuel into a combustion chamber of an internal combustion engine (hereinafter referred to as an "internal combustion engine"). It relates to a control valve.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection device in which pressurized high-pressure fuel is injected into a combustion chamber of an engine by an injector driven by an electrically controlled piezoelectric element, a piezoelectric device for controlling the injection of high-pressure fuel is used. A type control valve disclosed in U.S. Pat. No. 5,740,969 is known.

A piezoelectric control valve disclosed in US Pat. No. 5,740,969 accommodates a piezoelectric element for driving a valve member of an injection nozzle in a housing.
It is configured using materials having different types of thermal expansion coefficients.
Thereby, the temperature compensation is performed by making the thermal expansion coefficients of the housing and the piezoelectric element equal.

[0004]

However, in the above-described temperature compensation method, the displacement of the piezoelectric element is several tens μm.
On the other hand, the variation in the manufacturing dimensions of the piezoelectric element and the variation in the processing tolerance of the housing are so large that they cannot be ignored. Therefore, there is a problem that it is difficult to position the piezoelectric element and the valve element. Furthermore, the piezoelectric element and the housing thermally expand due to a change in temperature, and the zero point is shifted due to a difference in thermal expansion between the piezoelectric element and the housing. This makes it difficult to perform temperature compensation as designed.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a piezoelectric control valve in which temperature compensation is easy. It is another object of the present invention to provide a piezoelectric control valve capable of stably controlling fluid ejection.

[0006]

According to the piezoelectric control valve of the first aspect of the present invention, the detecting means includes a driving force transmitting portion for transmitting the driving force of the driving piezoelectric element to the valve element and the valve element. Detect contact. When a voltage is applied to the driving piezoelectric element when the driving force transmitting section and the valve element are not in contact with each other, the driving piezoelectric element expands in accordance with the magnitude of the applied voltage, and the driving force transmitting section and the valve element are connected to each other. Contact. By detecting the contact between the driving force transmission unit and the valve body, the contact point between the driving force transmission unit and the valve body, that is, the zero point can be detected. For this reason, for example, a bias voltage is applied to the driving piezoelectric element and the zero point is corrected, so that the driving force transmitting unit can be held near the zero point of the valve element. Therefore, temperature compensation can be easily performed, and stable fluid ejection control can be performed.

According to the piezoelectric control valve of the second aspect of the present invention, the valve body is arranged such that the driving force transmitting portion and the valve body come into contact with each other.
When assembling the driving piezoelectric element and the driving force transmitting unit to the housing, if the contact between the driving force transmitting unit and the valve body cannot be maintained due to the difference in thermal expansion between the driving piezoelectric element and the housing after assembly, In at least one of the cases where the contact between the driving force transmitting unit and the valve body cannot be maintained, the detection unit detects the contact between the driving force transmitting unit and the valve body. For this reason, zero point correction can be performed reliably, and temperature compensation can be performed reliably. Therefore, it is possible to constantly control the fluid ejection stably.

According to the piezoelectric control valve according to the third aspect of the present invention, since the detecting means has the detecting piezoelectric element, when the driving force transmitting portion comes into contact with the valve body, a compressive force acts on the detecting piezoelectric element. The generated potential is induced. The zero point can be easily detected by detecting the generated potential. Therefore, zero point correction can be easily performed with a simple configuration, and temperature compensation can be performed more easily.

According to the piezoelectric control valve according to the fourth aspect of the present invention, the detecting piezoelectric element drives the valve element when the contact between the driving force transmitting portion and the valve element is not detected. The amount of lift can be earned. Therefore, it can be applied to various uses and types of fluid ejecting apparatuses.

According to the piezoelectric control valve of the present invention, the detecting piezoelectric element and the driving piezoelectric element are integrally fired, and are divided into the detecting piezoelectric element and the driving piezoelectric element according to the electrode arrangement. Therefore, the detecting piezoelectric element and the driving piezoelectric element can be easily manufactured. Therefore, the number of manufacturing steps and the manufacturing cost can be reduced.

According to the piezoelectric control valve of the present invention, the detecting means detects the contact between the driving force transmitting portion and the valve body by detecting the urging force of the urging means. With the configuration, the zero point can be easily detected, and the zero point can be easily corrected. Therefore, temperature compensation can be performed more easily.

According to the piezoelectric control valve of the present invention, the detecting means applies the high-pressure fluid in the high-pressure fluid chamber to the valve element to increase the valve closing force of the valve element, thereby increasing the closing force of the valve element. When the driving force transmission unit and the valve element come into contact with each other, a relatively large force can be detected, and the accuracy of detecting the zero point can be increased. Therefore, the accuracy of the zero point correction is improved, and the accuracy of the temperature compensation is improved.

According to the piezoelectric control valve of the present invention, the stopper portion is formed on the inner wall of the high-pressure fluid passage and can be brought into contact by the valve body being fully lifted. The contact point between the driving force transmitting unit and the valve body is detected by detecting the full lift position that contacts the stopper and calculating the difference between this position and the lift amount of the valve body.
The zero point can be easily and accurately detected. Therefore, the zero point correction is facilitated and the accuracy of the zero point correction is improved, so that the temperature compensation is facilitated and the accuracy of the temperature compensation is improved.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 1 shows a first embodiment in which the piezoelectric control valve of the present invention is applied to an accumulator type fuel injection device. The injector 1 shown in FIG. 1 is supplied with high-pressure fuel at a constant pressure stored in a common rail (not shown) through a high-pressure fuel introduction passage 7 via a fuel pipe (not shown).

A needle valve 4 for opening and closing the injection hole 3 is reciprocally accommodated in a nozzle body 2 of the injection nozzle 10 provided on the injection hole side of the injector 1. The nozzle body 2 and the injector body 5 are connected by a retaining nut 17. A control piston 6 that is in contact with or is connected to the needle valve 4 is provided on the side opposite to the injection hole of the needle valve 4. Here, the needle valve 4 and the control piston 6 constitute a valve member. The end of the needle valve 4 opposite to the injection hole is inserted into a spring 18, and the spring 18 urges the needle valve 4 downward in FIG. 1, that is, in the injection hole closing direction. On the side opposite to the injection hole of the control piston 6, a pressure control chamber 20 as a high-pressure fluid chamber is formed. The control piston 6 includes a high-pressure fuel introduction passage 7 and a pressure control chamber 20.
And a throttle hole 11 that regulates the amount of fuel flowing into the pressure control chamber 20 is formed.

The high-pressure fuel introduced from the high-pressure fuel introduction passage 7 is branched into an injection nozzle fuel introduction passage 8 and a throttle hole 11. The high-pressure fuel branched into the injection nozzle fuel introduction passage 8 has a fuel reservoir 1 formed in an annular shape around the needle valve 4.
The high-pressure fuel supplied to the pressure control chamber 9 and branched to the throttle hole 11 is supplied to the pressure control chamber 20. The pressure of the high-pressure fuel in the fuel reservoir 19 is shown in the upper part of FIG.
The pressure of the high-pressure fuel in the pressure control chamber 20 urges the control piston 6 downward in FIG. 1, that is, the direction in which the needle valve 4 closes the injection hole 3. I do.

A fuel hole 12 is formed between the pressure control chamber 20 and the low-pressure fuel chamber 9. The low-pressure fuel chamber 9 is a passage for discharging surplus fuel in the injector 1 to the outside. A seat portion 50 having a tapered frustoconical surface is provided on an inner wall of a communication passage which can communicate the pressure control chamber 20 and the fuel hole 12.
Are formed. The seat 4 has a valve body 4 to be described later.
The 0 spherical member 41 can contact. Here, fuel hole 1
2 and the low-pressure fuel chamber 9 constitute a low-pressure space.

A valve body 40 is provided in the pressure control chamber 20. The valve body 40 is composed of a spherical member 41 as a contact portion and a spring 42 as an urging means. One end of the spring 42 is in contact with the spherical member 41 and the other end is in contact with the end of the control piston 6 on the side opposite to the needle valve. The spherical member 41 is urged in a direction in which the communication between the pressure control chamber 20 and the fuel hole 12 is interrupted.

A casing 30 is provided in the low-pressure fuel chamber 9, and a driving piezoelectric element 13 for opening or shutting off high-pressure fuel in the pressure control chamber 20 by driving the valve body 40 is provided in the casing 30. Have been. Casing 30
Is urged by the disc spring 35 toward the fuel hole side. The driving piezoelectric element 13 includes a plurality of disk-shaped piezoelectric elements stacked with a disk-shaped internal electrode interposed therebetween.
Power is supplied from a terminal 33 embedded in the connector 32. The driving piezoelectric element 13 expands when a voltage is applied to each piezoelectric element, and displaces the casing 30 toward the fuel hole 12 against the urging force of the disc spring 35. The driving piezoelectric element 13 contracts when the voltage applied to each piezoelectric element is cut off, and displaces the casing 30 toward the fuel hole side by the urging force of the disc spring 35.

A valve needle 15 as a driving force transmitting portion is fixed to a substantially central portion of the bottom end surface of the casing 30. The outer diameter of the valve needle 15 is smaller than the inner diameter of the fuel hole 12, and the valve needle 15 can be inserted into the fuel hole 12. It is displaced and can contact the spherical member 41 of the valve body 40. Therefore, when a voltage is applied to the driving piezoelectric element 13, the valve needle 15 is displaced downward in FIG. 1, that is, in a direction in which it contacts the spherical member 41, and pushes the spherical member 41. I get away from the seat 50 against the urging force,
The pressure control chamber 20 and the fuel hole 12 communicate with each other. Therefore, the valve needle 15 transmits the driving force of the driving piezoelectric element 13 to the valve element 40. The valve element 40, the driving piezoelectric element 13 and the valve needle 15 are housed in the injector body 5. That is, the injector body 5
Constitutes a housing.

A detecting piezoelectric element 16 as detecting means is provided between the inner bottom surface of the casing 30 and the end face of the driving piezoelectric element 13 opposite to the connector. Piezoelectric element for detection 1
Reference numeral 6 denotes a laminate of a plurality of disk-shaped piezoelectric elements sandwiching the same disk-shaped internal electrode, which is connected to a terminal 36 embedded in the connector 32. The detecting piezoelectric element 16 has a configuration in which the valve needle 15 contacts the spherical member 41 and a voltage is generated by applying a compressive load to each piezoelectric element to detect the contact between the valve needle 15 and the valve element 40. is there. The detecting piezoelectric element 16 and the driving piezoelectric element 13 are integrally fired, and are divided into the detecting piezoelectric element 16 and the driving piezoelectric element 13 depending on the electrode arrangement.
For this reason, the detecting piezoelectric element 16 and the driving piezoelectric element 1
3 can be easily manufactured, and the number of manufacturing steps and manufacturing cost can be reduced.

Next, the operation of the pressure-accumulation type fuel injection device having the above configuration and a method of detecting a zero point will be described with reference to FIGS. 1, 2 and 3. (1) When the voltage applied to the driving piezoelectric element 13 is interrupted, the driving piezoelectric element 13 is contracted, so that the valve needle 15 does not contact the spherical member 41 and the spring 42 is attached. The spherical member 41 is pushed upward in FIG. When the spherical member 41 is seated on the seat portion 50, communication between the pressure control chamber 20 and the low-pressure fuel chamber 9 is cut off.

In step S11 shown in FIG. 3, when high-pressure fuel is supplied into the injector 1 from the fuel pipe through the high-pressure fuel introduction passage 7, the pressure receiving area of the control piston 6 is larger than the pressure receiving area of the needle valve 4. , Spring 1
8 is acting in the injection hole closing direction, the sum of the force received by the control piston 6 in the injection hole closing direction from the fuel pressure in the pressure control chamber 20 and the biasing force of the spring 18 is the fuel in the fuel pool 19. It is larger than the force that the needle valve 4 receives in the lift direction from the pressure. Therefore, the injection hole 3 is closed by the needle valve 4 and no fuel injection is performed.

(2) In step S12 shown in FIG.
When a voltage is applied to the driving piezoelectric element 13, as shown in FIG. 2, the driving piezoelectric element 1 is proportional to the magnitude of the applied voltage.
3, the valve needle 15 is displaced and approaches the valve body 40 due to the expansion. Valve needle 15 and valve element 4
In a state where the spherical member 41 is not in contact,
The voltage generated in the detecting piezoelectric element 16 is extremely small. However, when the valve needle 15 comes into contact with the spherical member 41, a relatively large force is applied to the detecting piezoelectric element 16 due to the sum of the urging force of the spring 42 and the fuel pressure of the pressure control chamber 20, and the valve needle 15 and the spherical member 41 come into contact with each other. A higher voltage is generated than before contact with the member 41.

In step S13 shown in FIG. 3, the point of contact between the valve needle 15 and the spherical member 41, that is, the zero point, can be detected by detecting a change in the voltage generated in the piezoelectric element 16 for detection.

In step S14 shown in FIG. 3, when the valve needle 15 comes into contact with the spherical member 41, a voltage slightly smaller than the voltage applied to the driving piezoelectric element 13 is applied to the driving piezoelectric element 13 as a bias voltage. By doing so, the distance between the valve needle 15 and the valve element 40 can be made relatively small. That is, the valve needle 15 can be held near the zero point of the valve body 40, and the zero point can be easily corrected. Therefore, temperature compensation can be easily performed.

(3) When the voltage applied to the driving piezoelectric element 13 further increases, the valve needle 15 is further displaced downward in FIG.
Moves away from the seat portion 50 against the urging force of the spring 42, and the pressure control chamber 20 communicates with the fuel hole 12. Then, the high-pressure fuel in the pressure control chamber 20 is discharged from the injector 1 through the low-pressure fuel chamber 9, and the fuel pressure in the pressure control chamber 20 decreases. The fuel pressure in the pressure control chamber 20 decreases,
The sum of the force received by the control piston 6 in the injection hole closing direction and the biasing force of the spring 18 from the fuel pressure in the pressure control chamber 20 is as follows:
When the force exerted on the needle valve 4 in the lift direction by the fuel pressure in the fuel pool 19 becomes smaller, the needle valve 4 is lifted and fuel is injected from the injection hole 3.

In the first embodiment of the present invention, the valve element 40 and the valve element 40 are
When assembling the driving piezoelectric element 13 and the valve needle 15 to the injector body 5, the contact between the valve needle 15 and the valve body 40 cannot be maintained due to a difference in thermal expansion between the driving piezoelectric element 13 and the injector body 5 after the assembling. When the valve needle 15 and the valve body 40
In at least one of the cases where contact with the piezoelectric element cannot be maintained, the detecting piezoelectric element 16 detects the contact between the valve needle 15 and the valve body 40 and applies a bias voltage to the driving piezoelectric element 13. Thereby, the valve needle 1
5 can be held near the zero point of the valve element 40, so that the zero point correction can be reliably performed and the temperature compensation can be reliably performed. Therefore, stable fuel injection control can always be performed.

Further, in the first embodiment, when the contact between the valve needle 15 and the valve element 40 is not detected, the detecting piezoelectric element 16 can drive the valve element 40. The amount of lift can be earned. Therefore, the present invention can be applied to fuel injection devices mounted on various types of engines.

Further, in the first embodiment, the urging force of the spring 42 and the fuel pressure of the pressure control chamber 20 act on the valve body 40, and when the valve needle 15 comes into contact with the valve body 40, the detecting piezoelectric element is used. Since the zero point is detected by applying a relatively large force to the element 16 to generate a relatively large voltage, the accuracy of the zero point correction is improved, and the accuracy of the temperature compensation is improved.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
Shown in In the second embodiment, the valve body 140, the stopper 51,
A valve body chamber 57 and high-pressure fuel passages 58 and 59 are provided, and other configurations are the same as those of the first embodiment. First
The same reference numerals are given to the same components as those in the embodiment.

As shown in FIG. 4, the high-pressure fuel introduction passage 7 branches into a high-pressure fuel passage 58 communicating with the valve body chamber 57 on the way, and the valve body chamber 57 controls the pressure through a high-pressure fuel passage 59. It communicates with the chamber 20. The valve element 14 is provided in the valve element chamber 57.
The valve body 140 includes a spherical member 141 as an abutting portion and a spring 142 as an urging means. One end of the spring 142 is in contact with the spherical member 141 and the other end is in contact with the inner wall surface facing the seat portion 50. Therefore, the spring 142 is in the direction in which the spherical member 141 sits on the seat portion 50, That is, the spherical member 141 is urged in a direction in which the communication between the pressure control chamber 20 and the fuel hole 12 is interrupted. A stopper portion 5 having a tapered frustoconical surface on the inner wall facing the seat portion 50
1 is formed. When the valve body 140 is fully lifted, the spherical member 141 can contact the stopper portion 51. The valve body 140 is separated from the seat portion 50 or is seated on the seat portion 50 so that the valve body chamber 57 and the fuel hole 1 are separated.
Open or cut off the communication with 2. Also, the valve body 140
Is detached from the stopper 51, or the stopper 51
, The communication between the valve body chamber 57 and the high-pressure fuel passage 58 is opened or cut off. That is, the valve element 14
0, the seat portion 50 and the stopper portion 51 constitute a three-way valve.

Next, a method for detecting the zero point of the pressure-accumulation type fuel injection device having the above configuration will be described with reference to FIGS. 4, 5 and 6. FIG. The operation is the same as that of the first embodiment, and the description is omitted.

When a voltage is applied to the driving piezoelectric element 13 in step S21 shown in FIG. 6, the driving piezoelectric element 13 expands in proportion to the magnitude of the applied voltage as shown in FIG. Due to this extension, the valve needle 15 is displaced, and accordingly, the valve body 140 is lifted. Valve element 140
Is fully lifted, a relatively large reaction force acts on the valve needle 15, and the reaction force acts on the detection piezoelectric element 16, causing a potential difference in the detection piezoelectric element 16.

In step S22 shown in FIG. 6, the position where the valve element 140 is fully lifted can be detected by detecting this sudden increase in the potential difference. In step S23 shown in FIG. 6, the valve 1
The distance between the valve needle 15 and the valve element 140 is made relatively small by performing a calculation of subtracting the lift amount of the valve element 40, detecting the zero point of the valve element 140 and applying a bias voltage to the driving piezoelectric element 13. Can be kept.
That is, the valve needle 15 can be held near the zero point of the valve element 140, and the zero point can be easily corrected. Therefore, temperature compensation can be easily performed.

In the second embodiment of the present invention, the valve 14
0 detects the full lift point abutting on the stopper 51,
By calculating the difference between the full lift point and the lift amount of the valve element 140, the contact point between the valve needle 15 and the valve element 140 is detected, so that the zero point can be detected easily and with high accuracy. Therefore, the zero point correction is facilitated and the accuracy of the zero point correction is improved, so that the temperature compensation is facilitated and the accuracy of the temperature compensation is improved.

Further, in the second embodiment, when the contact between the valve needle 15 and the valve body 140 is not detected,
Since the detection piezoelectric element 16 can drive the valve element 140, the lift amount of the valve element 140 can be increased. Therefore, the present invention can be applied to fuel injection devices mounted on various types of engines.

In the embodiments of the present invention described above,
Although the piezoelectric control valve of the present invention is applied to the pressure accumulating fuel injection device, it is needless to say that the invention is applicable to various types of fluid injection devices.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment in which a piezoelectric control valve of the present invention is applied to a pressure accumulating fuel injection device.

FIG. 2 is a characteristic diagram showing a relationship between a voltage of a driving piezoelectric element, a displacement of a valve needle, a voltage of a detecting piezoelectric element, and time according to the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining a zero point detecting method according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a second embodiment in which the piezoelectric control valve of the present invention is applied to a pressure accumulating fuel injection device.

FIG. 5 is a characteristic diagram showing a relationship between a voltage of a driving piezoelectric element, a displacement of a valve needle, a voltage of a detecting piezoelectric element, and time according to a second embodiment of the present invention.

FIG. 6 is a flowchart for explaining a zero point detecting method according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 injector 3 injection hole 4 needle valve (valve member) 5 injector body (housing) 6 control piston (valve member) 9 low-pressure fuel chamber (low-pressure space) 10 injection nozzle 13 driving piezoelectric element 15 valve needle (driving force transmission unit) DESCRIPTION OF SYMBOLS 16 Piezoelectric element for detection (detection means) 20 Pressure control chamber (high pressure fluid chamber) 40 Valve 41 Spherical member (contact part) 42 Spring (biasing means) 50 Seat 51 Stopper 57 Valve body 140 Valve body 141 Spherical member (contact part) 142 Spring (biasing means)

Continued on front page F term (reference) 3G066 AA07 AB02 AC09 AD12 BA44 BA51 BA61 CC06T CC08T CC14 CC21 CC64T CC67 CC68U CC69 CC70 CD25 CD26 CE13 CE27 CE34

Claims (8)

[Claims] 1. A high-pressure fluid passage capable of supplying a pressurized fluid to an injection hole of a fluid injection nozzle, and a valve member for connecting and disconnecting the injection hole, wherein the high-pressure fluid passage is provided on an opposite injection hole side of the valve member. A piezoelectric control valve for interrupting a high-pressure fluid chamber for urging the valve member in the injection hole blocking direction by a fluid pressure supplied from a fluid passage and a low-pressure space including a low-pressure fluid passage or a low-pressure fluid chamber, A seat portion formed on an inner wall of a communication passage capable of communicating a high-pressure fluid chamber with the low-pressure space, a contact portion capable of sitting on the seat portion, and an urging means for urging the contact portion in a seating direction A valve body that opens and closes the communication path when the abutting part is separated from the seat part and seated on the seat part; and a driving body that expands by an applied voltage to drive the valve body. A piezoelectric element, and a driving force of the driving piezoelectric element. A driving force transmitting unit that transmits to the valve body; a housing that houses the valve body, the driving piezoelectric element and the driving force transmitting unit; a detecting unit that detects contact between the driving force transmitting unit and the valve body; A piezoelectric control valve comprising: 2. When assembling the valve element, the driving piezoelectric element and the driving force transmitting section to the housing such that the driving force transmitting section and the valve element come into contact with each other, the driving piezoelectric element is mounted after the assembly. At least one of when the contact between the driving force transmitting unit and the valve body cannot be maintained due to a difference in thermal expansion between the element and the housing, and / or when the contact between the driving force transmitting unit and the valve body cannot be maintained due to aging. 2. The piezoelectric control valve according to claim 1, wherein the detecting means detects a contact between the driving force transmitting section and the valve element. 3. The piezoelectric control valve according to claim 1, wherein said detecting means has a detecting piezoelectric element. 4. The piezoelectric control according to claim 3, wherein the detecting piezoelectric element drives the valve element when the contact between the driving force transmitting section and the valve element is not detected. valve. 5. The piezoelectric element for detection and the piezoelectric element for driving are integrally fired, and are divided into the piezoelectric element for detection and the piezoelectric element for driving according to an electrode arrangement. Piezoelectric control valve. 6. The sensor according to claim 1, wherein the detecting unit detects a contact between the driving force transmitting unit and the valve body by detecting an urging force of the urging unit. A piezoelectric control valve according to claim 1. 7. The contact means between the drive force transmitting unit and the valve element by causing the high-pressure fluid in the high-pressure fluid chamber to act on the valve element to increase the valve closing force of the valve element. The piezoelectric control valve according to any one of claims 1 to 6, wherein the control is performed. 8. A stopper formed on an inner wall of the high-pressure fluid passage and capable of coming into contact with the valve body when the valve body is fully lifted, wherein the detecting means detects a position at which the valve body comes into contact with the stopper part. The point of contact between the driving force transmission unit and the valve body is detected by calculating a difference between the position and the lift amount of the valve body, and the contact point between the driving force transmission unit and the valve body is detected. The piezoelectric control valve according to any of the preceding claims.