JPS5958129A - Fuel injection device - Google Patents

Abstract

PURPOSE:To make up a fuel injection device being capable of electronic control, with which improvements in fuel consumption, exhaust emission control, drivability and so on are achieved, by combining a piezoelectric element-make electrostriction actuator capable of high-speed action and a needle valve together. CONSTITUTION:In time of stoppage, a needle valve 104 is forcibly pressed against a valve seat 107 by dint of a spring 113 whereby fuel is not sprayed any more. In time of driving, the needle valve 104 goes up as far as a portion for clearance by the setting pressure of a regulator valve 3 and thereby the fuel is sprayed out of an injector. At this time, when an electrostriction actuator 120 is energized with a continuous rating current, it elongages, for example, by 50mum in length, overcomes the hydraulic pressure, makes the needle valve 104 stick fast to the valve seat 107 and stops the fuel injection. On the other hand, a computer 200 opens or closes an injection nozzle in an optimum manner on the basis of various engine parameters. The quantity of fuel injection can be controlled in high accuracy because its opening or closing time is extremely short as compared with the valve-opening time of a nozzle 100.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device used for fuel injection A:1 of an internal combustion engine for automobiles, and in particular a device that has a variable high-speed response and is suitable for electronic control of injection amount, injection timing, injection rate, etc. It is related to.

For example, in the case of EFI injectors, conventional fuel injection nostles could only be operated by opening and closing the nozzle. Therefore, although the injection timing and amount can be controlled, the injection rate cannot be changed. Furthermore, in the injection nozzle of a diesel engine, 11 parts are opened and closed by fuel pumped by an external injection pump, and parameters related to injection cannot be changed by the nozzle itself.

However, in recent years, there has been an increasing demand for electronic control of diesel engines in particular, and a device that can freely control parameters related to injection is desired.

In view of the above points, the present invention configures an electronically controllable fuel injection device by combining an actuator capable of high-speed operation and a needle valve, thereby achieving improved fuel efficiency, exhaust gas purification, and improved drapery. The purpose is to

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a system diagram showing the configuration of the present invention.

(3) is a fuel pump that pumps and supplies fuel sucked up from the fuel tank 2. 3 is a regulator valve, which opens when the pressure reaches a set pressure (for example, 20 MPa).
The discharge pressure of the pump 1 and the internal pressure of the pipe line 4 are kept constant. Reference numeral 5 stores fuel at a constant pressure in an accumulator, thereby suppressing transient pressure fluctuations in the fuel within the pipe 4 during fuel injection and stop. Reference numeral 6 is an electromagnetic relief valve which is closed when energized, and is connected to the train side when energized (for example, when the engine key switch is OFF), thereby releasing the pressure inside pipe 4 to atmospheric pressure. This is provided to stop fuel injection and stop the engine.

100 is a fuel injection nozzle, and its detailed configuration is as follows. lot is a nozzle body, and its lower part is integrally formed with a threaded part 102 for mounting to an engine etc. and a hexagonal part 103 for tightening. Reference numeral 104 designates a needle valve whose tip 1.05 has a conical shape, and has at least one hole in the center of the tip of the nozzle body 101.
A tapered valve seat 107 provided at the upstream portion of I7L106 is closed in an oil-tight manner. Valve seat 107
An oil chamber 108 for guiding fuel is provided at the upper part of the needle valve 104 along the circumference thereof. A passage 109 for supplying fuel to this oil chamber 108 is connected to the nozzle body 101.
It passes through the interior to the union 110, and the pipe line 4
connected to. The knee valve 104 is disposed oil-tightly and slidably within the cylinder portion of the nozzle body 101. Furthermore, the needle valve 104
A holding hole 112 is formed in the center of the holding hole 11.
2 contains a spring 113 and the needle valve 104
ζ is forced downward. 120 is an electrostrictive actuator, which expands when a voltage is applied. This electrostrictive actuator 120 will be described later d'L.

Reference numeral 115 denotes a bolt that is screwed into the threaded part carved in the second part of the nozzle body, and a hexagonal hole 117 for tightening is formed in the head of the bolt. The tip end 118 of this bolt 115 comes into contact with the 01■ electrostrictive actuator 120, so that the actuator 120, the spring 113, and the needle brake r104 are accommodated and held within the nozzle body 101.

Valve seat 107, needle valve 1.04, spring 113,
The positional relationship between the electrostrictive actuator 120 and the bolt 115 is as follows. Electrostrictive actuator 1.20
For example, the elongation that occurs when 100OV is applied to is △l
(for example, 50 μm), the electrostrictive actuator 120 does not stretch when the current is not applied, so the spring 113
Due to the stretching force of , the electrostrictive activeator 120
Press 15 and it will be pressed. On the other hand, the needle valve 104 is pressed against the valve seat 107, and the electrostrictive actuator 1
20 and the needle valve 104, there is a gap l' which is slightly shorter than Δl.

On the side of the nozzle body 101, there is an electrostrictive active.

A hole 130 is provided for passing an electric wire 119 for supplying electricity to the ether 120. This hole 130 also has a drain function for fuel that has leaked through the gap between the cylinder portion 111 of the nozzle body and the needle/valve 104. The electric wire 119 is connected to the computer 200. The computer 200 has an engine rotation sensor 201, a slot/nottle opening sensor 210, etc. as described later. water l
K! xsen-jl-212, intake pipe pressure sensor 213,
Signals such as starter switch and edge 238 are connected,
Based on these signals, the optimal injection timing, injection amount, and injection pattern are calculated to drive the fuel injection nozzle 100 and the electromagnetic relief normal valve 6.

FIG. 2 is a partial plan view of the electrostrictive actuator 120, with the phase structure not shown. 121 is an insulating material (for example, P
I) A cylindrical insulator \Using made of S'), and a groove 122 is provided on its side surface. 12
3, 124 is an insulator disk also made of an insulating material, which covers the open end of the insulator housing 121; In addition, Insi Break Disk 12
3 and 124 require strength because the force generated in the electrostrictive actuator is directly applied thereto. 125 is for example I)
A piezoelectric element consisting of Z'F, in this example, a straight i5! :3Qmm, thickness Q, 5mm 100
I am using one. Reference numeral 126 denotes an electrode plate for supplying voltage to the piezoelectric element 125, which is made of Verylum copper metal having a thickness of 30 μm.

1ijl The electrode plates 126 and the piezoelectric elements 125 are arranged alternately in the insulator housing 121, and the piezoelectric elements 125
are stacked so that they are electrically connected in parallel, and after blocking both ends with insulator disks 123 and 124,
The digit tabs 127 of the storage electrode plate 126 are connected by solder (-j).

Next, the operation of the needle valve 104 in the above configuration will be explained.

Figure 3 is the shore! FIG. 1 is a sectional view for explaining the operation of the injection nozzle. First, if we consider when the operation is stopped (Fig. 3 (
a)) The electromagnetic relief valve 6 is electrically connected to the non-energized side, and the pipe line 4 and the accumulator 5 are connected to each other.
, the passage 109 and the oil chamber 108 are at atmospheric pressure. has been done. Lit, knee 1 nil valve 104 is spring 1
13, and the fuel is not injected from the injection hole 10G.

Next, considering during operation, the electromagnetic relief valve 6 is closed because it is energized, and the pressure supplied from the furnace material pump 1 causes the tail piping system, such as the pipe line 4, the accuno-lator 5, and the passage 109, to be closed. , the oil chamber 108 is located above I set by the regulator valve 3 (for example, 20 MPa
) is pressurized. This oil pressure is Knee 1! Acting on the taper S1- at the lower part of the needle valve 104, the needle valve 104
Generates a force that pushes 04 upward.

Since the spring 113 is set to a sufficiently small value (for example, 2 ON) in response to this force, when the electrostrictive actuator 120 is not energized, the force is applied by the clearance with the knee valve 104. Due to this upward movement, a gap is created between the needle valve 104 and the valve seat 107, and fuel flows out through this gap and is injected from the injection hole 10G (Fig. 3(b)). The force pushing up the valve 104 is, for example, 20 M I)a, and the area on which the oil pressure acts on the needle valve 104 is 10-.
The value is 200M, and the time it takes for the needle valve 104 to rise above the clearance by 4° is extremely short (about 100μ5ec), making it possible to respond to business luck.

Next, in this state, when current is applied to the electrostrictive actuator 120, the electrostrictive actuator 120 attempts to extend by Δp (for example, 50 μm).

Since the shearing force generated by the electrostrictive actuator 120 is extremely large (approximately 20 ON in this example), the hydraulic pressure is lower than the knee valve 10.
Press down 4 to overcome the force (20 ON) (push this downward, and the needle valve 104 and valve seat 107 come into close contact and stop the injection of fuel 1'+1) (see Figure 3). C))
The response time of the electrostrictive actuator 120 is approximately 50 to 100
It is extremely fast (μsec), and in combination with its powerful force, the time required for the nozzle closing operation is also extremely short, enabling high-speed response.

Based on the above explanation of basic opening and valve closing operations, the operation of the system will now be explained.

FIG. 4 is an operational waveform diagram of each part used to explain the operation of the system.

First, turn on the engine key switch (■ in Figure 4 a)
, the computer 200 starts operating and closes the electromagnetic relief valve 6 by energizing it.
Indicated by 0 in FIG. 4 d, the fuel injection nozzle is closed by further energizing the electrostrictive actuator 120 (indicated by ◎ in FIG. 4 f).

Subsequently, by starting the engine, fuel is supplied from the fuel pump 1 (indicated by ■ in FIG. 4), and the pressure in the piping system increases (indicated by ■ in FIG. 4e). The computer 200 determines whether the engine has rotated a specified number of revolutions (for example, five times), and when this number of revolutions is exceeded, it assumes that the pressure has decreased to the set value and starts controlling fuel injection. Figure 4 [indicated by 0 points (4)].

Reactor material injection control is basically performed by opening and closing the fuel stop nostle 100. The computer 200 determines the optimal injection timing and injection amount based on signals such as engine speed N1, throttle opening θ, water temperature 'r, and intake pipe pressure P.
The engine crank angle reference position signal (fourth
Fig. C), the fuel injection nozzle is opened and closed at the timing determined from the angle signal (indicated by ■ in Fig. 4 r). The fuel supply pressure is kept constant by the regulator valve 3 and the accumulator 5, and the gap between the knee valve 104 is also constant, so the fuel injection amount is kept constant by the fuel injection nozzle 100.
It is proportional to the valve opening time.

Further, since the time period between the valve opening operation 11 and the valve closing operation of the nozzle is extremely short, a high degree of control is possible.

After that, when the engine key switch is turned OFF (indicated by ■ in Figure 4 a), the computer 200 stops operating.
Since the electromagnetic relief valve 6 is no longer energized, it is opened (not shown by the ◎ point in Fig. 4 d).

Therefore, it is electrically connected to the drain side, and the pressure in the piping system is released (as shown by ■ in Fig. 4 e), injection stops, and the engine stops.

At this time, since the needle valve 104 is pressed against the valve seat 107 by the spring 113, the fuel remaining in the piping system 4 is prevented from leaking from the injection hole 106.

Next, the configuration and operation of the computer 200 will be explained.

FIG. 5 is a block diagram showing the configuration of computer 200. Reference numeral 201 denotes an engine rotation sensor, the rotation shaft of which is directly connected to the drive shaft 1001 of the fuel pump 1 described above.

More fuel, J! The drive shaft tool of the pump l is the engine 10.
They are connected by pulleys 1002 and 1005 so that the rotation speed ratio is 1/2 of that of the crankshaft 1004 of 03. In order to output a reference position signal of one pulse per revolution, the engine rotation sensor 201 includes a rotary plate 202 having one notch on the circumference, a reference position sensor 203 that detects this notch, and a reference position sensor 203 that detects this notch. It is composed of a rotary plate 204 having 360 notches on the circumference in order to output an angle signal of 360 pulses, and an angle sensor 205 that detects the ψJ notches. Note that the phase relationship between the reference position signal and the angle signal is optimized by tlI!
I! has been done.

Reference numeral 210 denotes a throttle opening sensor using, for example, a potentiometer, whose drive shaft is connected to an accelerator 211, and output is increased by converting the degree of depression of the accelerator, that is, the throttle opening, into an electrical signal. 212 is a hot water sensor using, for example, a thermistor, whose resistance value changes depending on the temperature of the engine cooling water and outputs it as an electrical signal. 2
Reference numeral 13 denotes an intake pipe pressure sensor that utilizes the fact that the balance of a resistance bridge formed on a semiconductor diaphragm changes depending on pressure, for example, and outputs the internal pressure of the engine intake pipe as an electrical signal.

A first shaping circuit 220 shapes the waveform of the signal from the reference position sensor 203 and outputs a reference position valve with a short time width synchronized with the fall of the reference position sensor 203 signal. A second shaping circuit 221 shapes the waveform of the angle sensor signal 205 and outputs a short level angle pulse at its rising and falling edges. That is, a signal of 720 pulses is obtained per 1 rotation of the engine rotation sensor 201. 222 is a first AD conversion circuit that AD converts the signal from the throttle opening sensor 210 into 12 bits.
Convert it to a digital value and send it to the CPU 235th pass line 2
Connect to 60. 232 is a second ΔD conversion circuit which converts the signal from the ice processor 212 into a 12-bit digital value and connects it to the pass line 260 of the CPU 235. 224 is the third AD conversion circuit and the intake pipe pressure sensor 21
3 is converted into a 12-bit digital value and connected to the pass line 260 of the CPU 235.

225 is a clock generation circuit that generates clock signals ψ1 and ψ2 with stable frequencies. A 12-bit binary counter A 226 is latched and reset to 1 by the reference position pulse from the first shaping circuit 220, and is counted to 1 by the clock signal φI. Of course, the counter Δ226 is >! ” = Position! The dock signal φ electric is sent each time from Hals to the position pulse from the base 71. Therefore, this value corresponds to the period of the reference position pulse. , this reciprocal corresponds to the engine rotation speed.Then, this counter A2
The output of 26 is connected to pass line 260 so that CP tJ 235 can read it. 227 is a 12-bit binary counter B;
ff! The reference position pulse from +220 is connected to the clock input, and the angle pulse from the second shaping circuit 221 is connected to the clock input. Therefore, the contents of the counter B227 indicate the momentary rotation angle from the reference position synchronized with the rotation of the drive shaft of the fuel pump. Let this be ψ. 22
8 is a 12-bit latch A, which is CPL1235 which will be described later.
The calculated fuel injection timing ψI is latched and output. 2
29 is a comparator A of l2)) i L, which compares the rotation angle ψ from the reference position with the fuel injection timing ψ1, and outputs a level signal when the angle becomes ψ-ψ1. Reference numeral 230 denotes a 12-bit binary counter C, to which the reset signal is connected to the above-mentioned ψ-ψ1 signal, and to its clock input is connected to the clock signal φ2. Therefore, the contents of the counter C indicate the elapsed time from the moment when ψ-ψ is reached. Let this be t. 23
1 is l 21) C P which will be described later in latch B of it
Fuel injection period calculated by U 235 1. Latch and output. 232 is 1ii with 12 bit comparator B
The elapsed time from ψ-ψ1 as described above is compared with the injection period t1, and when the result becomes 1-1, a coincidence signal of 1 level is output. Reference numeral 233 is a mono 1-reset flip-flop knob, whose set input receives a coincidence signal ψ-ψI, and its reset input receives a matching signal of 1=1. A matching signal is connected. Therefore, this flip-flop is reset seven times at the fuel injection timing ψ1 to become a reher, and after that t1, it is reset and a signal having a 0 level is outputted to the output 0iil child Q.

This output is input to a drive circuit 178240 that drives the electrostrictive actuator 120 of the fuel injection nozzle 100.

234 is the reading time of the starter switch 239 11Ji
Starter switch 2390) ON, OF
F to the pass line 260. CPU
235 is 12 bit and its interrupt terminal I N 'V1
The reference position pulse from the first shaping circuit 220 is input manually, and the optimal fuel is determined based on signals from the engine rotation sensor 201, throttle opening sensor 210, water tM sensor 212, and intake pipe pressure sensor 213. The tuna timing ψI is set before the injection period L1) and output. 236 is a ROM that stores the II program and data, and 237 is a CI
) This is RAM for U work.

A power supply circuit 250 is connected to the engine from the battery 300 through a switch 238, and supplies a constant voltage to each part of the computer 200. Furthermore, a 100OV DC voltage is generated for driving the electrostrictive actuator.
The signal is supplied to the drive circuit 240.

Note that the battery voltage of the electromagnetic relief valve 6 is supplied via the engine key switch 238, and the engine
1--When the switch is turned on, the electromagnetic relief valve 6 is energized and closed.

The operation of a computer with the following configuration will be explained below.

FIG. 6 is a waveform diagram of various parts for explanation, and FIG. 7 is a flowchart of the program 1. First, when the engine key switch 238 is turned on, power is supplied to the computer 200 and the computer 200 starts operating. At the same time, the electromagnetic relief valve 6 is energized and closed. Wait 9 (step ls+) until the starter switch 239 is turned on after performing various input processing in the MAIN routine. When the starter switch 239 is turned on, the starter flag is set to 1 in step 2S2, and interrupts are permitted in step 3S3, resulting in an idle state.

When the engine is started (when a heavy position pulse is generated, I N Tl is activated by this interrupt (step 4S4). In the I N i' l routine, the starter flag is checked (step 5S5)), even if this is 1. In this case, it is determined that injection is not possible because the pressure in the piping system has not increased until the reference position pulse comes 5 times, and the injection timing is set to ψ1.
-0, the injection period tl=Q and returns (step 6 S t: ). When the engine rotates once, turn the starter flag to O (step 7S7),
Move to driving state.

First, the period of the reference position pulse is controlled from the counter A226 (step 8Se), and from this value, the engine rotation speed N
1 is alWed (step 9S9).

Next, the sl:l nol opening degree signal is read from the first ΔI conversion circuit 222 (step 1O3+o), and the s11 no.I
- the lever opening θI is increased by 1llW (step 11S++).

1'J I
, find 1s1ψ1 at the time of fuel injection at 01 o'clock by interpolation 1 calculation (
Step 123+2). Next, in the same manner, the injection period during N2O2 is calculated by 1 from the NOt map to the interpolated itW (step 13s13). Next, fa2 A l) Conversion time RR223J-Rewater i4 sensor 213 (7) Value #
jt insertion (step 14sI4), water temperature T” +1W
+ is alWed (step 15S+s). Then the third
Intake pipe pressure sensor 2I from AD conversion times +18224
3 no i! 1'C+ reading (step 16S+t;),
Suction 'at tube IJg force P l wal calculation Z+ (S-F-7'7" l I S I 7).

Then the above 1'l! Injection timing, injection Il from the value of W l, 1) ■ (calculate the correction amount of the period by 81 to correctly determine the injection timing ψI and injection period t1, step 18S+e)
, output ψ1 to latch A228 and output Ll to latch A228, respectively.Return to step 19519).

Based on this signal, the SOJ counter B2 is operated as described above.
27, counter C 230, comparator 229, comparator B 232, fly-knopf 17 nop 233, drive circuit 240 J, a predetermined signal force (output to the electrostrictive actuator to perform fuel injection.

Incidentally, step 4 S4 is performed every time IN'Fl/rechin (standard) <Rus arrives, and
! This LiS will be used to sensor the injection. Then, when the engine key switch 238 is turned off, the electromagnetic relief valve 6 is no longer energized and opened, the pressure in the piping system is released, injection becomes impossible, and the engine stops.

In addition, in the explanation of 1 and 2, for simplicity, in the case of a wall multi-cylinder model assuming a single cylinder, the counter B227 and the counter C
230, comparator Δ229, comparator B23
2. Prepare latch A228, latch 13231, flip-flop 233, and drive circuit 240 for each device,
This can be handled by generating a reference pulse at the dry grass position for each cylinder.

Next, the second drive circuit 240 will be explained.

FIG. 8 shows the circuit of the drive circuit 240 (FIG. 18 is shown. The output of the flip-flop 233 described above is connected to the input terminal
241. This signal is level at the time of injection and 0 level at the time of non-off operation. Now, considering the non-injection time, an O level signal is coming to the input terminal 241. This signal is inverted by the inverter ICI and becomes a level, which turns on the 1-run transistor Q1 via resistors R1 and R2, and turns on the 'ζ1 transistor Q2 via resistors R3 and R4. The emitter of transistor Q2 is connected to the aforementioned power supply circuit 11R.
250J, 1000V/Ii? Ti pressure is supplied, and electrostriction -r passes through the collector of 1-run risk Q2.
100 OV is supplied to the Kujikoator 120. As a result, the electrostrictive actuator 120 extends by △ρ and knee 1'
Press the valve I04 to close the valve seat 107 and inject
stop. At this time, the 1-run sisters Q3 and Q4 are
l” F in l, (it is.

On the other hand, during injection, an L level signal is applied to the human power input 6181 and 241, which is inverted by the inverter ICI and becomes the 10th level, turning the transistor Q3 into the OFF state via resistors R5 and R6.
NL, and one transistor Q4 via resistors R7 and R8.
Turn on. At this time, transistors Q1 and Q2 are both O
Since F F is applied, the applied voltage of the electrostrictive actuator 120 becomes Ov, and the needle valve 104 is contracted by Δp, and the needle valve 104 is pushed up by the oil pressure G to open and start injection.

In addition, in this example, even if the wall Ii IE i' explained using transistors, Sirisk, vacuum tube, etc. be.

As described above, in the first embodiment of the present invention, the nozzle valve is opened by a constant pressure of oil pressure supplied from the fuel pump l, while the valve is closed by the electrostrictive actuator 120.
Since this is done by expanding L), both operations respond in an extremely short time. Furthermore, since the nozzle opening time corresponds to the fuel injection amount -
By performing highly precise fuel injection, it is possible to easily achieve improvements in fuel efficiency, exhaust gas, and TI.

In particular, since the electrostrictive actuator 120 with laminated piezoelectric elements 125 is used as the drive source for the nozzle, it is physically possible to operate at high speed, and is smaller than the conventional solenoid 1 and can provide high-speed response.

Furthermore, in conventional nozzles of this type, the nozzle drive source is turned off.
Since the return action when F is performed is by a spring, the spring force cannot be increased due to the force balance with the driving source, or if the spring force is increased, the force of the driving source must also be increased in proportion to it. Therefore, there was no choice but to increase the size and υ, and as a result, there was a problem that high-speed response could not be obtained even with Dorora. However, in this embodiment, -ζ is characterized in that the return operation is performed by hydraulic pressure, so no spring is required, and the t° speed response is improved even during return.

Next, a second embodiment of the present invention will be described.

When the engine is at -r idle, it is desirable to inject a small amount of fuel relatively slowly from the viewpoint of vibration, noise, etc. However, in the first embodiment, the applied voltage is, for example, OV, 100
There are two types of OV, and the fuel injection nozzle 100 is controlled only in fully open and fully open states, so the amount of fuel injected per unit time (hereinafter referred to as injection rate) is constant regardless of engine conditions. , cannot answer the above request.

As is well known, the amount of expansion of the piezoelectric element 125 is proportional to the applied voltage. Therefore, the electrostrictive actuator 120 using this piezoelectric element 125 can perform linear operation by changing the applied voltage.

Therefore, in the second embodiment, the electrostrictive actuator 120 is linearly operated by utilizing this characteristic.
By making the t amount variable, the injection rate can also be controlled at the same time.

Hereinafter, a second embodiment of the present invention will be described based on the operation waveform diagram of each part shown in FIG. 9.

The operations at the time of starting and stopping the engine are the same as those in the first embodiment, so they will be omitted and will only be explained when the engine is running.During operation, a hydraulic pressure of approximately 20 MPa is applied to the piping system. is being pushed up in three directions by this hydraulic pressure.

Now, the applied voltage of the electrostrictive actuator 120 required for the needle valve f104 to come into close contact with the valve seat 107 is 1ooov.
Then, when this tooov is set to 1, the electrostrictive actuator 120 expands by Δβ and the needle valve 104
is forced downward (hTIr), so fuel injection is not performed.

Next, at a predetermined injection timing ψ1 calculated by the computer, the voltage applied to the electrostrictive actuator 120 is changed from 1000V to 500V! (indicated by ◎ in Fig.
When the applied voltage is 0■ (fully open), the gap Δβ is half, so the flow path area is also half, and the amount of fuel ejected from the nozzle is ≧1', min when fully open. The injection rate can also be set to 1/2 of fully open n5 (wc9 Figure d)
).

Then, when the applied electric current I ball of the electrostrictive activator 120 is set to 4" (indicated by ◎ in FIG. 9C), knee 1 nil j "10
The gap between the valve seat 107 and the valve seat 107 becomes smaller, and the injection rate also becomes smaller (indicated by '4' in Figure 9d). Conversely, lowering the applied voltage increases the injection rate. By linearly changing the voltage applied to the electrostrictive actuator 120, the injection rate can also be linearly changed.

After the start of injection, after a predetermined injection period (indicated by 11 in Fig. 9) has elapsed, the voltage applied to the electrostrictive actuator 120 is reduced to 100 OV (indicated by ◎ in Fig. 9C). 104 and the valve seat 107 are in close contact with each other, the nozzle is fully opened, and injection stops. In this way, in the second embodiment, by varying the voltage applied to the electrostrictive actuator 120, the needle valve 104 and the valve seat 107 are
7 can be changed and the injection rate can be controlled freely. Therefore, fuel injection can be performed at an optimal injection rate or injection pattern depending on the engine condition 1'1.

Next, the computer 200 in this second embodiment will be explained.

Since the configuration of the computer is almost the same as that of the f81 embodiment, only the necessary parts will be explained. FIG. 10 is a block diagram for explaining the computer 200', and the parts indicated by thick lines are different from the first embodiment. 225' is a clock generating circuit which generates a constant frequency clock signal. The click signal φ3 is, for example, a signal with a period of 1 ooμsec. 270 is ND game i, and one human power is injection timing ψ1 and injection period L1 made by flip-flop 233.
The injection signal is ff1l and u7 for the other manual input.
The signal φ is connected. ΔND game I・270
The output is the second interrupt MIiA completed IN of the CPU 235.
Connected to T2. The second terminal I N T 2 is the first
The interrupt priority level is lower than that of the terminal INT1. 271 is a 12-bit latch C and the CPU
The value loaded from 235 is recorded 1q. This latch C271 is provided with a reset terminal Y, to which a signal passed from the flip-flop 233 and passed through the inverter 272 is connected. In other words, Furinobufu 1. l Knob 2
When the output of 33 is O (during non-injection), the inverter 27
2, the latch content is forcibly set to 0 because the signal from Lebel is input to the 7th node terminal R. 273 is latch C with 12-bit 13A conversion circuit 11δ
It converts the digital value loaded through 271 into a voltage of 1. When the digital human power is O (when fully open), it is 10, and when the digital human power is A - 1 (when fully open). The voltage becomes Ov. ) and the voltage becomes -C. Also, 280 is a drive circuit for the electrostrictive actuator.

Details of the drive circuit 280 are shown in FIG. The output (terminal 281) of the I)A converter 273 is connected to the non-inverting input of the operational amplifier ICl0 via a resistor R11. The portion after the W amplifier ICl0 is the drive circuit 24 shown in the first embodiment.
This is a buffer section for outputting high voltage with almost the same configuration as 0. However, since linear operation is required, each
- By changing the bias of the transistor. 11. from the output 282 of the buffer section. Negative feedback is applied to the inverting input of the operational amplifier ICl0 via E resistors R20 and R121. The ratio of C resistor R20, ■≧21 is selected to be 99:1, and a voltage of 1/100 of the buffer output terminal 282 is applied to the inverting input of the operational amplifier ICl0.

Now, a voltage of 5 ■ is applied to the human-powered glass 281. Initially, the voltage at terminal 282 is 0, so the operational amplifier IC
The inverting input of l0 is 0■, and the output of operational amplifier IC10 rises to about 11■. Therefore, through the resistors RI2, R, 3, the l-run lister Ql.

becomes conductive, and one transistor QI2 becomes conductive via resistors RI4 and RI5, so that -r l 000 V
Current flows from the power source. Thereafter, as the voltage across the glass 282 rises, the voltage at the inverting input of the operational amplifier ICl0 also rises, so the output voltage of the operational amplifier ICl0 decreases and the current flowing through the transistor QI2 is suppressed. terminal 28
When the voltage of 2 becomes 500■, the voltage of the inverting input of the operational amplifier ICl0 becomes 1/10 with flW resistors R20 and R2+.
The voltage is divided into 0 and becomes 5■, which becomes the same as the voltage of the non-inverting input and becomes stable. If for some reason the voltage at terminal 282 goes above 5F, the l-run listers QI3 and Q1
4, the output is reduced and stabilized. As described above, the drive circuit shown in FIG. 11 can be regarded as an amplifier with a voltage gain of 100 times.

With the above configuration,
The operation of 00' will be explained.

FIG. 12 is a) l''-chart, and FIG. 13 is a signal waveform diagram of each part. The MAIN routine is a start-up process, which is the same as in the first embodiment. Also, Isa? The lNTl routine is activated by the 1% + pulse, and the injection timing ψ1 and injection time corresponding to the engine line 1'1 are set! The step of correcting tel and outputting it to latch Δ and latch B is also the same as in the first embodiment. At this time, since the flip-flop 233 is closed, the latch C271 is also reset.
The output voltage of the Δ converter 273 is 10■, and the drive 101
A voltage of 100 OV multiplied by 100 is applied to the electrostrictive actuator 120 at path 280, and the nozzle is closed.
raI3 shown as 0 in Figure e1). After this, CI) U 23
5 is an address ΔDR in the ROM that stores the injection pattern every 100 μsec corresponding to the current engine condition e1.
Writes I to the specified address ADR2 in the RAM and returns. Thereafter, when the predetermined injection timing ψ1 is reached, the flip-flop 233 is activated seven times (Fig.
) The reset of latch C271 is released and ΔN
One input of D gate 270 becomes the rubel. Since the clock signal φ3 with a period of 100 μsec is connected to the other human power, in the injection timing diagram, the l N i of the CPU
' An interrupt signal is added every 100 μsec to the 2 terminal (Fig. 13C) a I NT2 f line is I N
Read A I) Rl from the contents of 8DR2 of RAM 237 written in T1, and read ΔDR1 of ROM 236.
The contents of the address are output to latch C271. and A.D.R.
Increment I and write to 8DR2 of CRΔM and return. The contents of latch C271 are DΔ converter 27
3, is converted into an analog voltage, is amplified by the drive circuit 28°0, and is applied to the electrostrictive actuator 120 (13th
Figure e).

Repeat the above INT2 operation every 100μsec,
After a predetermined injection period (indicated by t1 in the 131st PIb), the flip-flop 233 is turned off (◎ in Fig. 13).
), latch C271 is reset and injection ends.
(indicated by ■ in Figure 13 d). At this time, since the ΔAND gate 270 is also closed, the interrupt signal of I NT 2 is no longer generated.

In this way, during the injection period, the injection rate pattern stored in the ROM is output every l Q Q p s e c, and its value can be selected from any value from fully open to fully closed. Therefore, it is possible to freely control the injection rate.

Note that there are various other possible injection rate controls in the second embodiment. One of them is (as shown in Figure 14,
Prior to the main injection, ζ Pyro 7 injection I1. l lj may also be performed. Therefore, immediately after the main injection, there is at least one small amount of combustion for a short period of time. It is a device that injects 1.
It is effective in reducing movement, noise, noise, etc. during IT rotation.

Next, a third embodiment of the present invention will be described.

The piezoelectric element 125 of the electrostrictive actuator 120 used in this embodiment has a diameter of 3Q++m, a wall thickness of Q, and a diameter of 5 mm, and its resonance frequency is approximately 4 MH.
z, which is a frequency in the ultrasonic range. In the first and second embodiments, the needle valve 104 and the valve seat 100 are connected to the needle valve 104 and the valve seat 10 by applying a constant DC voltage to the electrostrictive actuator 120 or at a frequency 1 minute lower than the resonant frequency.
7 gap was changed and the U injection amount was controlled. It is widely known that atomization occurs when a liquid comes into contact with an object that is being vibrated by ultrasonic waves. In this embodiment, a high frequency signal is superimposed on the DC voltage for opening and closing the nozzle, and the needle valve 104 is ultrasonically vibrated with the U knee 1 lube + 104 open to promote atomization of the fuel. The first goal is to achieve accurate combustion by atomizing the fuel ejected from the injection holes.

The third embodiment will be explained below with reference to waveform diagrams of various parts shown in FIG.

The operations when starting and stopping the engine are the same as those shown in FIG. 4, so the explanation will be omitted and only the operation will be considered. First, in order to open the nozzle, the applied voltage of the electrostrictive actuator 120 is changed from, for example, tooov to O■ (Fig. 15C).
(Indicated by ◎ in the middle), the needle valve 104 is moved upward by hydraulic pressure.
It is pushed up and a gap is created between it and the JF seat 107, and the fuel*1 flows out. In this state, the electrostrictive actuator 120 is
A high frequency signal of 0KIIz is applied to generate ultrasonic vibrations (shown by Cl1j0 in FIG. 15). Needle: (I'
1.04 is a powerful electrostrictive actuator 120 using hydraulic pressure.
Since it is pressed against the electrostrictive actuator 120
The vibration of the needle valve 104 is transmitted to the needle valve 104.
4 vibrates with ultrasonic waves. The fuel passing through the lower taper portion 105 of the needle valve F104 causes cavitation due to ultrasonic vibrations when the needle valve R104 rises, and receives compressive force when the needle valve F104 descends, becoming atomized and released from the injection hole 106. gush.

The period of atomization using ultrasonic waves is: 1 computer 20
Needle valve 10 is optimally controlled by 0 at an appropriate time.
The vibration of No. 4 is cut off (indicated by ◎ in Fig. 15C). After that, by applying a voltage of, for example, 100 OV to the electrostrictive brake 120, the needle valve 104 is moved to the valve seat 10.
7 (indicated by ■ in Figure 15C) to complete the fuel injection).゛In this embodiment as well, the timing of ultrasonic vibration can be freely controlled by the computer 200, so it is possible to create an atomization state suitable for the engine conditions, so that the combustion of the engine is good, and the vibration,! S! sound,
It has a beneficial effect on fuel efficiency, etc.

Next, the computer 200 in the third embodiment will be explained.

The configuration of the computer 200 is almost the same as that in the first embodiment, so only the necessary parts will be explained. FIG. 16 is a block diagram for explaining the computer 200, and the parts indicated by thick lines are different from the first embodiment. 225' is a clock generation circuit that generates a clock signal of a constant frequency. The clock signal φ4 is a signal for ultrasonic vibration, for example 5
This is a signal with a frequency of 0KIIz. 401 is 12 bits
The reference position pulse is reset by the binary counter l].
・The angle pulse is connected to the 11.1 human power input.

Therefore, the contents of counter I) 401 are based! It shows the moment-by-moment rotation angle from Hiiragi's position. Let this be ψ.

The counter D can also share the counter B shown in FIG. 4 of the first embodiment. In that case, counter D is not necessary. 402 is a 12-bit latch D and CPU235
The ultrasonic wave 1 movement start time ψ2 performed by W is latched and output. 403 is a 12-bit comparator C that calculates the rotation angle ψ from the reference position and the start of ultrasonic vibration 1s1ψ2
, and when ψ - ψ2 is reached, a Lebel coincidence signal is output. 404 is a 12-bit binary counter E
Then, the coincidence signal ψ−ψ2 is used for the reset manually,
Two signal furnaces are connected to the clock manually. Therefore, the contents of the counter E404 indicate the elapsed time from the moment when ψ-ψ2 was reached. This is L
'. A 12-bit comparator 405 compares the elapsed time t' from ψ-ψ2 with the ultrasonic vibration period t2, and outputs a Lebel coincidence signal when t'=t2. Reference numeral 407 denotes a reset flip-flop, to which a match signal ψ-ψ2 is connected to the reset 2, and a match signal t'=t2 is connected to the reset 2.

Therefore, this flip-flop 407 is set at the ultrasonic vibration start time ψ2 to become a level, and is reset at t2#&, and a signal having a 0 level is output to the output terminal Q. This signal is input to a drive circuit B410 for causing the electrostrictive actuator 120 to vibrate ultrasonically. 25
0゛ is a power supply circuit that supplies stabilized power to each part of the computer, and also supplies power to the drive circuit for opening and closing the nozzle.
00OV high voltage, ultrasonic vibration drive circuit 13410
A voltage of 50V is supplied to the The nozzle opening/closing signal from 240 is output to the drive circuit via an inductor L421 for blocking high frequency signals for ultrasonic vibration, and when the ultrasonic vibration of drive circuit B410 starts, the DC component of the nozzle opening/closing signal is blocked. Therefore, it is supplied to the electrostrictive actuator 120 via a capacitor C420.

Drive time 1? &A240 is the same as that shown in FIG. 8 in the first embodiment, so the explanation is omitted, and the drive circuit B410
This will be explained below. f(i) Figure 17 is a circuit diagram of drive circuit B for ultrasonic vibration used in this example. The signal is at terminal 44
This signal is connected to ND game L I
Enter one input of C20. The output of a flip-flop 407 that generates an ultrasonic vibration timing signal is connected to the other input of the AND game IC20, and only when this signal is level, a signal of 50 Kllz is output to the output of the AND game IC20. do. This signal passes through a DC blocking capacitor C21, a resistor R21, a line 22,
Enters the base of transistor Q21 biased by R23. The primary side of the coupling 1 lance '1'1 which is amplified by the 1-run lister Q21 and entered the collector side and the capacitor 02
If-ti 11 is filtered at tank times IIδ with 2 and inputted to the bases of -ζ1- transistors Q22 and Q23 through the coupled lance 'l''l. It is biased by , and works as a class B punosuple amplifier circuit by the output transformer '■'2. D21 and D22 are for protection between pace emitters when I/Lan listers Q22 and Q23 are reverse biased. C23 is for surge absorption. Impedance matching is performed by the output l lance 'I'2, and an ultrasonic vibration signal is supplied to the electrostrictive actuator 120.

The operation of the above-described configuration of computer 200 will be described next.

FIG. 18 is a flowchart 1. FIG. 19 is a waveform diagram of each part for explanation. The MΔIN routine is a start-up process and is the same as in the first embodiment, so its description will be omitted. The l N T 1 routine is activated by the reference position pulse, and the injection timing ψl and injection period 1 . The process up to calculating and correcting the value and outputting it to the latches A1 and B is the same as the first embodiment. The computer continues to be N1
, θ1 is determined in advance by a bench test and stored as data in the ROM 236.
The θψ′ map is drawn and the ultrasonic vibration start time ψ2 at N, 01 is determined by interpolation calculation. Then do the same and NO
The L' map is drawn and the ultrasonic vibration period t2 at N1.61 is determined by interpolation 111W. Next, the water temperature i” II W
1, intake pipe negative pressure P1), ψ2 and t2 are corrected, output to latch D and latch E, and return.

From then on, the hardware will automatically set the predetermined injection timing ψ.
A signal of 1 indicating the injection period is output to the flip-flop 7 233 (◎ in FIG. 19), and the nozzle opening/closing valve is operated by the drive circuit Δ240. Furthermore, a predetermined ultrasonic vibration start time ψ
2. The signal of ultrasonic vibration period t2 is sent to the flip-flop 4.
07 (FIG. 19) and ultrasonic vibration is applied by the drive circuit B410.

It is easily assumed that the third embodiment can be combined not only with the first embodiment but also with the second embodiment, and in this case, the injection timing, the distance between two injection holes, the injection rate, and the atomization state can be controlled. This makes it possible to inject fuel that is more suitable for the engine condition, which has excellent effects on improving movement, noise, emissions, smoke, etc.

As explained above, in the device of the present invention, since an electrostrictive actuator using a piezoelectric element is used as the drive source of the injection nozzle, injection control can be achieved by high-speed operation using electric signals. This has the excellent effect of being able to precisely control fuel injection characteristics accordingly.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the first embodiment of the device of the present invention, and the second embodiment is
The figures are a perspective view showing a sectional view of the electrostrictive actuator shown in FIG. 1, FIG. 5 is a circuit diagram of the computer shown in FIG. 1, FIG. 6 is an operational waveform diagram of the computer shown in FIG. 5, FIG. 7 is a flowchart of the computer shown in FIG. 5 is an illustrated drive circuit diagram, FIG. 9 is an operation waveform diagram of each part of the second embodiment of the device of the present invention, and FIG. 10 is a circuit showing main parts of the computer of the second embodiment of the device of the present invention. Figure 11 is a circuit diagram of the nozzle path shown in Figure 1, ¥1
12 is a flowchart (not shown) of the computer shown in FIG. 1, FIG. 13 is an operation waveform diagram of each part of the second embodiment of the device of the present invention, and FIG. 14 is a diagram of each part of another embodiment of the device of the present invention. FIG. 15 is an operating waveform diagram of each part of the third embodiment of the device of the present invention, FIG. 16 is a circuit diagram showing the main parts of the computer of the third embodiment of the device of the present invention, and FIG.
The figure is a circuit diagram showing the nozzle path shown in Figure 1, and Figure 18 is a circuit diagram showing the nozzle path shown in Figure 1.
Flowchart showing an 11 program of the illustrated computer
1., FIG. 19 is an operation waveform diagram of each part of the third embodiment of the device of the present invention. 1...(ffAil pump, 2...fuel tank, 1
04... Needle side, 120... Electrostrictive actuator, 125... Piezoelectric element. Agent Bri Riju Takashi Okabe! (j 6 1・1 -163- jTs 7 1・'1 10th country ~ 1 sheet - r+'! 12 1"1 Procedure? di official book (Rikimochiaki fullso March f r, 1 Showa "1157 special a'" Request ffl No. 169183 2 Name of the invention tll +! 14, Iwatani (4(i9)) Co., Ltd. J: Il
Tree 1! ,I! Representative of rlJI Width Parts Comprehensive Fill Institute
III II + Shogo 4th generation Osamu 〒448 I-1-5, Sho Vll-cho, Kariya-shi, Aichi Prefecture?
ni i “Order 11 I・1 Shipping F! II/(fl+58 February 2211 No. 3
Figure (a) (b> (C) 167

Claims (2)

[Claims] (1) An oil chamber to which fuel at a predetermined pressure is supplied, and a fuel chamber that communicates with this oil chamber: l injection hole, a needle valve that opens and closes this fuel injection hole, and a needle valve that opens and closes this fuel injection hole, and moves this needle valve toward the fuel injection hole side. The needle valve includes a spring that biases the needle valve, an electrostrictive actuator made of a piezoelectric element that drives the needle valve, and a computer that outputs a control signal to the electrostrictive actuator, so that when the electrostrictive actuator is extended, the needle valve A fuel injection device configured to close an injection hole. (2) The fuel fit injection device according to claim 1, wherein the electrostrictive actuator switches the needle valve between fully open and fully open in response to a control signal from the computer. (31nil electrostrictive actuator) The fuel injection device according to claim 1, characterized in that the opening degree of the knee valve is determined according to a control signal from the computer. (41ff1l electrostrictive actuator The fuel injection device according to any one of claims 1 to 3, wherein the needle valve is caused to vibrate ultrasonically in response to a control signal from the computer.