JPS61271881A - Control device for electrostriction type actuator - Google Patents

Abstract

PURPOSE:To make the injection rate variable when the device is applied to a fuel injection valve, by providing a means, which controls the discharging amount of electric charge, which is supplied to an electro-striction type actuator, and controlling the operating stroke of the electrostriction actuator in response to the discharging amount of the electric charge. CONSTITUTION:A means, which controls the discharging amount of electric charge that is supplied to an electrostriction actuator 5, is provided. the operating stroke of the electrostriction actuator 5 is controlled in response to the discharging amount of the electric charge. For example, when a thrystor 33 is turned ON and the electric charge in a capacitor 31 flows into the actuator 5, LC resonance is generated by a coil 32 and the actuator 5. The maximum voltage of 500V is applied to the actuator 5 in correspondence with the positive phase. Thereafter, the thrystor 33 is automatically turned OFF in correspondence with the negative phase of the LC resonance. Then, the electric charge of the actuator 5 is discharged to a capacitor 36 through a coil 34 and a thrystor 35. The voltage of the capacitor 38 can be adjusted through a resistor 37.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for an electrostrictive actuator, and is particularly used for a fuel injection valve of an internal combustion engine that injects fuel directly into a combustion chamber such as a diesel engine. The present invention relates to a control device for an electrostrictive actuator that controls the lift amount of a needle.

[Conventional technology]

In conventional control devices for this type of electrostrictive actuator, the operating stroke is constant, so when such an electrostrictive actuator is applied to a fuel injection valve, the nozzle area is constant and the amount of fuel is constant. Control is performed only by the valve opening time.

However, in such conventional devices, the fuel injection rate is constant, so when the operating range is wide like a passenger car engine, the injection period is too long at high speeds, causing a drop in output, or vice versa. The problem arises that the injection period is too short at low speeds, resulting in worsening of noise.

[Problem that the invention seeks to solve]

The present invention has been made to solve such problems, and the actuation stroke of an electrostrictive actuator is controlled by controlling the discharge amount of electric charge supplied to the electrostrictive actuator. Therefore, when this invention is applied to a fuel injection valve, In addition, the injection rate can be made variable by obtaining two stable opening areas corresponding to the two cases of full lift and partial lift of the nozzle needle. This is designed to satisfy both the time and the requirements for each injection period.

[Means for solving problems]

According to a basic form of the present invention, the electrostrictive actuator is provided with means for controlling the amount of discharge of electric charge supplied to the electrostrictive actuator, and the operating stroke of the electrostrictive actuator is controlled according to the amount of discharge of the electric charge. A control device for an actuator is provided.

According to a second aspect of the present invention, there is provided a means for controlling the amount of discharge of electric charge supplied to the electrostrictive actuator, and expansion and contraction of the electrostrictive actuator caused by the supply and discharge of electric charge to the electrostrictive actuator. Provided is a control device for an electrostrictive actuator, which includes a nozzle needle that seats on or lifts from a valve seat depending on the amount of charge released, and the amount of lift of the nozzle needle is controlled depending on the amount of discharge of the electric charge.

Furthermore, according to a third aspect of the present invention, there is provided a means for controlling the amount of discharge of charge supplied to the electrostrictive actuator, and a means for controlling the residual voltage of the capacitor provided as the means for controlling the amount of charge. A means for storing a voltage value when the engine rotational speed or output stops changing in response to a change in residual voltage, and a nozzle needle that seats on or lifts from the valve seat in response to expansion and contraction of the electrostrictive actuator. In addition, there is provided a control device for an electrostrictive actuator in which the amount of lift of the nozzle needle is controlled by controlling the residual voltage of the capacitor to the stored voltage value.

[For production]

According to the above configuration, the operating stroke of the electrostrictive actuator is controlled by controlling the amount of discharge of charge supplied to the electrostrictive actuator. Therefore, when a nozzle needle is provided that seats on or lifts from the valve seat in response to the expansion and contraction of the electrostrictive actuator, the lift t of the nozzle needle is controlled in accordance with the amount of charge released, thereby fuel The opening area of the injection valve is controlled.

In this case, in order to adjust the residual voltage of the capacitor provided as a means for controlling the amount of discharge of charge supplied to the electrostrictive actuator, the residual voltage is sequentially increased with each revolution of the engine, and By memorizing the voltage value when a change in engine speed or output is saturated and setting the residual voltage of the capacitor to the memorized voltage value, the lift amount of the nozzle needle can be adjusted to a desired stable point. can be a value corresponding to .

〔Example〕

FIG. 6 shows the structure of an electrostrictive fuel injection valve 1 as an example to which the present invention is applied. This injection valve 1 is used, for example, in a diesel engine, and injects fuel at each specific phase of the engine. The casing 2 of the injection valve 1 consists of a nozzle holder 3 and a retaining nut 4, and inside the casing 2, from above in the axial direction, an electrostrictive actuator 5, a pump piston 6, a disc spring 7, a distance piece 8, and a nozzle complete 9 are installed. is stored. The nozzle complete 9 is composed of a nozzle body 10 and a nozzle needle 11. The nozzle body 10 has an axial through hole 12 with a non-uniform diameter at the center of the axis, and from above the through hole 12, a needle guide 13, a fuel reservoir 14, a seat portion 15,
A spout 16 is formed. Note that the seat portion 15 has a conical shape.

A nozzle needle 11 is housed in the through hole 12 so as to be movable in the axial direction. The nozzle needle 11 has a large diameter portion 17 from above.
, a conical part 18, a small diameter part 19, and a large diameter part 1.
7 can slide within the needle guide 13 with a gap of 20 μm in diameter. Further, when the conical portion 18 is seated on the seat portion 15, the electrical communication between the fuel reservoir 14 and the nozzle port 16 is cut off. Note that 18 and 15 are in line contact, and the contact portion is located on the side of the conical portion 18 closest to the small diameter portion. The small diameter portion 19 is in such a state that it approximately passes through the nozzle 16 when the conical portion 18 is seated on the seat portion 15, and the gap between the two is approximately 50 μm in diameter. The tip of the small diameter portion 19 is provided with a notch 20 for expanding the spray shape into a conical shape. The nozzle needle 17 is movable in the axial direction, but its lower limit is the conical part 1
8 is seated on the seat portion 15, its upper limit is the large diameter portion 17.
This is when the upper end surface is in close contact with the lower end surface of the distance piece 8. Although the distance piece 8 is provided with a through hole 21 coaxially with the through hole 12 of the nozzle body 10,
This through hole 21 is closed by the upper end surface of the nozzle needle 11 when the nozzle needle 11 reaches the upper limit position. In the nozzle holder 3, between the upper surface of the distance piece 8 and the lower surface of the pump piston 6, there is a space 22 in which the disc spring 7 exists, and this space forms a pump chamber 22. The pump chamber 22 is pressurized and depressurized as the electrostrictive actuator 5 expands and contracts.
1 on the upper end surface of the nozzle needle 11 to raise and lower it. The electrostrictive actuator 5 has a cylindrical shape in which disk-shaped elements and foil-shaped electrodes are alternately laminated, and a voltage is electrically applied to each disk-shaped element. . A lead wire 23 for applying voltage is taken out to the outside of the nozzle holder 3 via a grommet 24, and constitutes a part of an electric circuit 25, which will be described later. A constant fuel pressure, for example, 200 kg/cd, is always supplied to the injection valve 1 by devices such as a high-pressure pump, a pressure regulator, and an accumulator (not shown). This fuel reaches the oil reservoir 14 from the inlet boat 26 provided in the nozzle holder 3 through the nozzle holder 3, the distance piece 8, and the passage 27 in the nozzle body 10. Unless the liquid is seated on the part 15, it is ejected to the outside from the nozzle 16. aisle 2
7, a dowel pin 28 is used so that the relative position between the nozzle holder 3 and the distance piece 8 does not change, and a ring is used so that the relative position between the distance piece 8 and the nozzle body 10 does not change. A shaped groove 29 is provided in the nozzle body 10.

Next, the basic configuration of the electric circuit 25 is shown in FIG.

The electrostrictive actuator 5 includes a DC-DC converter 30
The generated voltage of 300 cm is once stored in a capacitor 31 and then supplied via a coil 32 and a thyristor 33. To explain this operation, when the thyristor 33 is turned on and the electric charge of the capacitor 31 flows into the electrostrictive actuator 5, LC resonance occurs between the coil 32 and the electrostrictive actuator 5, and its positive phase causes electrostriction. A maximum voltage of 500 cm is applied to the actuator 5. Thereafter, the thyristor 33 is automatically turned off by the negative phase of this LC resonance. Next, the electric charge of the electrostrictive actuator 5 is discharged to a capacitor 36 via a coil 34 and a thyristor 35.

Further, the voltage of this capacitor 36 can be adjusted via a resistor 37 by a transistor. To explain this operation, when the thyristor 35 is turned on, the electric charge of the electrostrictive actuator 5 is released to the capacitor 36 in proportion to the voltage difference between the electrostrictive actuator 5 and the capacitor 36. At this time as well, the coil 34 and the capacitor 36 cause LC resonance, and the thyristor 35 is automatically turned off. Since the electrostrictive actuator 5 expands due to the inflow of electric charge and contracts when the electric charge is released, the amount of contraction of the electrostrictive actuator 5 can be controlled by controlling the voltage of the capacitor 36 with the transistor 38. This is the translation.

At the beginning of use, in the case of the injection valve l shown in Fig. 6, 200 kg/cj of fuel is first supplied by an external pressure source, and this fuel reaches the oil reservoir 14 through the passage 27 and is injected into the nozzle needle l. It acts on the conical part 18 to try to raise the nozzle needle 11. However, the fuel in the oil reservoir 14 is 20μ between the nozzle needle large diameter portion 17 and the guide portion 13.
It reaches the pump chamber 22 through the gap of m and the through hole 21 of the distance piece, and acts on the upper end surface of the nozzle needle 11 to lower it, so the nozzle needle 11 has a seat part due to the difference in pressure receiving area. Seated at 15 and spout 16
The supplied fuel will not be injected from the nozzle 16. At the beginning of use, the circuit 25 in FIG.
In this case, the DC-DC converter 30 is connected to the battery 1, for example.
Boost 2V to 300■ and charge capacitor 310
Next, when the thyristor 33 is turned on, a voltage of 500 cm is applied to the electrostrictive actuator 5, and the electrostrictive actuator 5 expands. After the above process, both the injection valve 1 and the circuit 25 wait for an instruction to start injection. The instruction to start injection is given by turning on the thyristor 35. When the thyristor 35 is turned on, almost all of the electric charge in the electrostrictive actuator 5 is transferred to the capacitor 36, and accordingly, the electrostrictive actuator 5 is contracted and the pump chamber 22 is closed.
Reduce pressure. Therefore, the force acting on the upper end surface of the nozzle needle 11 is overcome by the force acting on the conical portion 18, and the nozzle needle 11 rises, brings its upper end surface into close contact with the lower end surface of the distance piece 8, and stops at that position. At this time, the fuel in the oil reservoir 14 passes through the gap between the conical part 18 and the seat part 15, and further passes through the gap between the small diameter part 19 and the injection port 16, and is injected to the outside, that is, into the combustion chamber of the diesel engine. The instruction to end the injection is given by turning on the thyristor 33. When the thyristor 33 is turned on, an electric charge is supplied from the capacitor 31 to the electrostrictive actuator 5, and the electrostrictive actuator 5 expands, increasing the pressure in the pump chamber 22 and seating the nozzle needle 11 on the seat portion 15. to end the injection. The amount of fuel injected is controlled by the injection period, which is known per se. Another feature of the present invention is that the amount of injection can be changed by selectively controlling the gap area between the injection port 16 and the small diameter portion 19 of the nozzle needle in two stages. In Fig. 2, the horizontal axis shows the lift of the nozzle needle 11 (that is, the axial distance from the lower limit position of the nozzle needle 11 to the actual position), and the vertical axis shows the minimum constriction area of the passage for the injected fuel. It is. Point 0 is when the nozzle needle 11 is seated on the seat portion 15, and between O and A, the gap between the nozzle needle conical portion 18 and the seat portion 15 is the minimum aperture.

Between A-8 is the case where the part of the small diameter part 19 of the nozzle needle except the notch 20 is inside the nozzle 16, and the gap area between the small diameter part 19 and the nozzle 16 is constant regardless of the lift of the nozzle needle 11. This is the minimum aperture. B-
C is a process in which the part of the small diameter part 19 of the nozzle needle without the notch 20 moves away from the nozzle 16, and the further away, the larger the aperture area becomes. Note that the zero point is a state in which the upper end of the nozzle needle 11 is in contact with the lower end of the distance piece 8. Among O~^-B-C in FIG. 2, the minimum aperture area is stable in O, A-B, and C. The present invention is A-B
The feature is that the injection amount is controlled by selectively using two aperture areas: and C. To obtain lift between A and B, use circuit 2.
5 transistor 38 is activated. When the injection valve 1 has finished injecting, the capacitor 36 is filled with the charge released from the electrostrictive actuator 5 and has a terminal voltage of, for example, 400 V. If the transistor 38 completely discharges the charge in the capacitor 36, the nozzle needle 11 can be lifted up to point C as explained above. However, for example, if the transistor 38 only discharges the residual voltage of the capacitor 36 to 200 V, the electrostrictive actuator 5 will not be sufficiently compressed to start the next injection, and the lift of the nozzle needle 11 will not be sufficient. It is possible to stay anywhere between A and B. The voltage of the capacitor 36 may be determined in advance in order to keep the lift of the nozzle needle 11 between A and B. It is desirable to monitor whether the engine speed or output decreases when the engine speed or output decreases, and perform learning control to determine that the required residual voltage is reached when the decrease stops, that is, at point B.

The reason why point B is preferable to point A is that nozzle needle 1
1 is lifted, the fuel pressure in the oil sump 14 is
This is to reduce the influence of the nozzle needle 11 descending by entering the pump chamber 22 through the gap between the nozzle needle 11 and the guide portion 13 . The transistor 38 is connected to the capacitor 36 so that when the accelerator opening of the engine is detected and the detected value is below the set value, the lift is at point B, and when it exceeds the set value, the lift is at point C.
shall be discharged.

Next, a control circuit that performs the above-mentioned control will be explained. FIG. 3 is a block diagram showing the configuration of the control circuit. 110
is an input interface with the following functions 0 A signal plate attached to the engine camshaft (not shown) 1
An angle sensor 122 detects 720 protrusions carved at equal intervals on the outer periphery of 21. In other words, the output l pulse of the angle sensor 122 corresponds to the engine crank angle l'' CA.The signal play) 121 has one protrusion 123 for detecting the reference position, and this is used as the reference sensor 12.
4 to detect. Angle sensor 122 and reference sensor 12
The output signal No. 4 is input to the input interface 110 and sent to the pass line 114 as engine rotation speed information. 125 is the accelerator opening sensor and the accelerator 126
The input interface 11 converts the accelerator opening degree into voltage by a rotating potentiometer 125 connected to the input interface 11.
Enters 0. The input interface 110 converts this voltage into A
The signal is converted into D and sent to the pass line 114. A starter signal that turns ON when the starter starts is also input to the input interface 110, and is sent to the pass line. 1
11 is a CPU that performs calculation control. 112 is a ROM that stores program data; 113 is a CI'U 11;
1 working RAM and data storage RAM. 114
is a path line for exchanging data. 1
15 is D that outputs a reference voltage calculated by CPU, which will be described later.
This is an A conversion circuit. 116 is an output interface,
Controls the injection valve 1. The injection time τ calculated by the CPU,
When the value of the injection timing θing is set, trigger signals for the first thyristor 33 and the second thyristor 34 are output at predetermined timing based on the reference signal and angle signal described above. The details of the drive circuit 25 will be explained below. The output of battery 50 is connected to DCD via keys 5-51.
A high voltage of approximately 300 V is input to the C converter 30 and is constantly stored in a large capacity capacitor 31. This voltage is connected to the electrostrictive actuator 5 via a series circuit of a first coil 32 and a first thyristor 33. The gate circuit of the first thyristor 33 is connected to the first trigger signal from the output interface 116 via an insulating pulse transformer 43. The electrostrictive actuator 5 is connected to a capacitor 36 via a series circuit of a second coil 34 and a second thyristor 35.

The gate circuit of the second thyristor is also connected to the second trigger signal from the aforementioned output interface 116 via the insulating pulse transformer 44. A transistor 38 is connected in parallel to the capacitor 36 via a resistor 37, and the base terminal of the transistor 38 is connected to the output of a comparator 39 via a resistor 40. A voltage obtained by dividing the voltage of the capacitor 36 to 1/100 by resistors 41 and 42 is connected to the non-inverting input of the comparator 39, and a voltage obtained by dividing the voltage of the capacitor 36 to 1/100 is connected to the non-inverting input of the comparator 39.
The output voltage of No. 5 is connected to the reference voltage ■□.

To explain the operation of this part, when the second thyristor 35 is triggered, the voltage <#5oov) stored in the electrostrictive actuator 5 is absorbed into the capacitor 36 via the second coil 34 and the second thyristor 35. As a result, the voltage of the capacitor 36 increases to approximately 400V. This voltage is divided to 1/100 by resistors 41 and 42 and input to the node inverting input of the comparator 39. On the other hand, the inverting input has V
If a constant voltage of REF, for example 2■, is manually applied, the output of the comparator 38 becomes l'', which makes the transistor 38 conductive through the resistor 40, discharges the capacitor 36 through the resistor 37, and the voltage drops.Capacitor 36 When the voltage drops to 200■, the output of the comparator 39 becomes "O", so the transistor 38 becomes 0FFL, the capacitor 36 stops discharging, and the voltage is also maintained.In other words, the voltage reached by the capacitor 36 is VIIF x 100V.
will be controlled by.

When V IIEF is set to OV, the voltage of the capacitor drops to Ov, so when the second thyristor 35 is 1-triggered, the voltage difference between the electrostrictive actuator 5 and the capacitor 36 is large, and a large amount of charge is transferred from the electrostrictive actuator. The current flows to the capacitor 36, and the amount of contraction of the electrostrictive actuator becomes maximum. Conversely, when (2) and , are increased, the voltage of the capacitor 36 also increases, the amount of charge transferred from the electrostrictive actuator decreases, and the amount of contraction decreases.

Note that the first thyristor 33 and the second thyristor 35 in the drive circuit 25 can be replaced with transistors, respectively, and in this case, it is not necessary to use the coils 32 and 34 forcibly.

Next, the operation of the control circuit 100 with the above configuration will be described below. FIG. 4 is a flow chart for explaining the operation. At the beginning of the main routine shown in FIG. 4(A), various initializations are performed, and the voltage ①8 to be controlled is set to OV at point B in FIG.

This voltage V is automatically set to the optimum point B by learning control.
The gist of the present invention is to correspond to the points.

The starter signal is read, and if the starter is ON, it is determined that the engine has started. At this time, a large amount of injection is required, so
■, Set it to = 0 and perform a full lift. If the engine is not starting, the learning flag is checked, and if the engine is learning, it merges with the starting routine. During startup or learning, the engine rotates regardless of the accelerator opening, so the injection amount is controlled only by the rotation speed.

The engine speed NE is read from the input interface 110, and the injection time and injection time of the injection valve are used from the map. Further, V REF is set to V (during startup, during OV% learning, increases by IOV per rotation) and returns to the beginning. After the learning is completed, the learning flag is O, so the injection control routine corresponding to normal operation is entered. Read the engine speed N and accelerator opening Accp, and determine the injection amount Q and injection time θing from the map. Next, check whether the accelerator opening Accp is wider than a predetermined opening, for example 10%. If it is less than 10%, use a small lift to prevent noise, and if it is over 10%, use a large lift to increase output. do. In the case of a small lift, the injection period is determined from the injection amount Q by a linear function of τ=KQ. Then VIEF
=Vs (voltage after learning to be controlled to point B). In the case of a large lift, if the opening area is five times that of a small lift as shown in FIG. 2, the injection flow rate will be five times as large, so the injection period τ may be one-fifth of that of a small lift. That is, τ=11
Find it in 5KQ.

Then, in order to achieve a large lift, VllEF=O is set. After that, the injection period τ, injection time θing, and reference voltage Vmtr that have been found are stored in the memory and the process returns to the beginning. Next, the interrupt routine shown in FIG. 4(B) will be explained. The interrupt routine is activated every engine revolution. VREF, τ, and θing are read from the memory and output to the DA conversion circuit 115 and the output interface 116.

Thereafter, the output interface 116 automatically generates the first trigger signal and the second trigger signal at predetermined timing,
Controls the injection valve 1. Next, check the learning flag.

If learning has finished, there is nothing to do, so return immediately. If learning is in progress, check the rotation speed. The previous rotational speed NEi-1 and the current rotational speed are compared, and if the difference is less than a predetermined value ε, then ■ is stored and learning is completed.

If the difference is greater than or equal to a certain value ε, Vs to continue learning.
=Vm + 10V. This learning method will be explained in more detail. FIG. 5 is a diagram for explaining the learning method. The lower the VIIEF, that is, the residual voltage of the capacitor 36, the larger the needle stroke of the injector 1 becomes. From FIG. 2, which shows the relationship between needle lift and injection amount, when VREF is 0, injection is performed at point C in FIG.

In other words, since the injection amount is large, the engine speed becomes high.

From this state, when VIItF is increased by IOV for each revolution, the injection amount decreases from point C to point B in FIG. In other words, the engine speed gradually decreases as shown by line C-B in FIG. Eventually it will reach point B, but B-A
Since this is a region where the injection amount does not change even if the lift I changes, the engine speed does not change as shown in FIG. 5.

Therefore, without looking at the change in engine speed, V R
EF can be gradually increased and the point where there is no change can be defined as point B. Furthermore, since this learning method is carried out immediately after starting, it also has the advantage that it can also be used to automatically increase the starting amount as shown in FIG.

In the above description, an embodiment has been described in which the needle lift is switched depending on the magnitude of the accelerator opening, but this may also be done depending on the magnitude of the engine rotational speed. The present invention is also effective when the above-described fuel injection valve 1 is used as a hydraulic control device having a similar structure.

〔Effect of the invention〕

1.) In controlling the operating stroke of the electrostrictive actuator 5, the present invention does not control the amount of the supplied charge 4i, but controls the amount of charge emitted from the electrostrictive actuator 5.

Generally, the amount of charge to be supplied is controlled by controlling the voltage generated by the DC-DC converter 30, but this has the disadvantage that the response is extremely poor due to the presence of the capacitor 31. The present invention controls the amount of charge released from the electrostrictive actuator 5 at the start of injection by adjusting the voltage of the capacitor 36 during the injection stop period, which is a sufficient period, so that a sufficient control response speed can be obtained. .

2.) In the present invention, a small diameter portion 19 with a uniform diameter is provided at the tip of the nozzle needle 11 so as to face the nozzle 16, and as shown in FIG. It can be stabilized in two ways, between the 0 point and the intermediate lift A-B. Therefore, the injection valve 1 can be used as if it had two large and small nozzles. For example, when the accelerator opening is small, A-
The injection rate can be controlled to a lift close to B between B to reduce noise, and when the accelerator opening is large, the lift can be controlled to C to increase the injection rate and output can be increased.

3.) In controlling the lift of the nozzle needle 11 to be close to B between A and B in FIG. 2, the present invention increases the residual voltage of the capacitor 36 by a constant value, and then increases the The residual voltage at the moment when the drop reaches saturation is used thereafter. By doing this immediately after starting, a natural starting increase can be obtained and accurate determination of residual voltage can be made without unpleasant changes in engine speed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the basic configuration of one embodiment of the control device for an electrostrictive actuator according to the present invention, and FIG. 2 is a lift amount of a nozzle needle in an electrostrictive fuel injection valve to which the present invention is applied. FIG. 3 is a circuit diagram showing a specific configuration of an embodiment of a control circuit used in a control device for an electrostrictive actuator according to the present invention; Figures (A) and (B) are flowcharts for explaining the operation of the control circuit shown in Figure 3. Figure 5 shows the residual charge discharge capacitor used in the control circuit of Figure 3. FIG. 6 is a diagram showing the relationship between voltage and engine speed. FIG. 6 is a diagram showing the configuration of an electrostrictive fuel injection valve as an example to which the present invention is applicable. (Explanation of symbols) 1... Electrostrictive fuel injection valve, 5... Electrostrictive actuator, 11... Nozzle needle, 16... Spout, 25... Electrostrictive actuator drive circuit, 33 ,3
5... Thyristor, 36... Charge release capacitor, 38... Transistor, 39... Comparator. 5- Electrostrictive actuator 36. - [Load release capacitor 251. Electrostrictive actuator 3B
-) Runnostar drive circuit Figure 2 Figure 4 (B) VREF (capacitor residual voltage) Figure 5

Claims (1)

[Scope of Claims] 1. The electrostrictive actuator is characterized by comprising means for controlling the amount of charge released to be supplied to the electrostrictive actuator, and the operating stroke of the electrostrictive actuator is controlled in accordance with the amount of charge released. A control device for an electrostrictive actuator. 2. As a means for controlling the amount of charge released, the electrostrictive actuator includes a capacitor from which the charge is released and a means for controlling the residual voltage of the capacitor before the charge is released. A control device for an electrostrictive actuator according to item 1. 3. A means for controlling the amount of discharge of charge supplied to the electrostrictive actuator, and a means for seating on the valve seat or valve according to the expansion and contraction of the electrostrictive actuator caused by the supply and release of charge to the electrostrictive actuator. 1. A control device for an electrostrictive actuator, comprising a nozzle needle that lifts from a seat, and the amount of lift of the nozzle needle is controlled according to the amount of discharge of the electric charge. 4. Claim 3, wherein a lift area is provided in which the opening area of the nozzle does not change with respect to the lift of the nozzle needle, and the lift amount of the nozzle needle is controlled to be the lift amount within the lift area. A control device for the electrostrictive actuator described above. 5. The electrostrictive type according to claim 4, wherein when the opening degree of the accelerator lever or accelerator pedal of the engine is below a set value, the lift amount of the nozzle needle is within the lift range. Actuator control device. 6. The scope of the claim, wherein the means for controlling the amount of charge released includes a capacitor from which the charge of the electrostrictive actuator is released, and a means for controlling the residual voltage of the capacitor before the charge is released. 4. A control device for an electrostrictive actuator according to item 3. 7. Means for controlling the discharge amount of charge supplied to the electrostrictive actuator, and engine speed or output in response to changes in the residual voltage in adjusting the residual voltage of the capacitor provided as the means for controlling the discharge amount. and a nozzle needle that seats on or lifts from the valve seat in accordance with the expansion and contraction of the electrostrictive actuator, and the residual voltage of the capacitor is stored in the memory. A control device for an electrostrictive actuator, characterized in that the lift amount of the nozzle needle is controlled by controlling the voltage value to a certain voltage value.