JPS58155232A - fuel supply device - Google Patents

Abstract

PURPOSE:To improve the ability of rapid response in a simple structure by constructing a part of a partition wall of a fuel chamber of a vibration plate for increasing the fuel pressure by the vibration of an electric transducer of this vibration plate and discharging the fuel from an injection nozzle. CONSTITUTION:A fuel supply device 3 is arranged in the downstream of a throttle valve of a suction pipe, and provided with a casing 302 with a fuel injection nozzle 301 projected from a side wall. The inside of this casing 302 is partitioned into the first and the second fuel chamber 305 and 306 by a vibration plate 303 fixed in three sides on the inner wall and a partition wall 304 supporting the remained one side of the vibration plate 303. On the side of the chamber 306 of the vibration plate 303, a movable winding 315 is fast fixed to be arranged in the gap of a permanent magnet 316 fixed on the casing, and the vibration plate 303 can be vibrated by the electrification control to this winding 315. By the vibration of this vibration plate 303, the fuel in the second chamber 306 is discharged via a pressure valve 312, the first chamber 305, and a discharge valve 308.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply device, and more particularly to a fuel supply device having a fuel control device function for an internal combustion engine.

Conventionally, electronic fuel injection devices have been used as fuel control devices for internal combustion engines. In the known electronic fuel injection system, the fuel required by the engine is metered by a solenoid valve9, that is, the solenoid valve is driven in pulses, and the amount of fuel supplied is controlled by the opening time of the solenoid valve3. In such conventional solenoid valves, it was planned to improve the high-speed response by increasing the utilization rate of the iron core that constitutes the solenoid and making it smaller1. However, the utilization rate was improved by increasing the magnetization of the iron core When the magnetic flux is increased, a considerable delay occurs in valve opening due to so-called magnetic aftereffect, which causes a delay in magnetic flux decay even after the magnetizing current is cut off. That is, there arises a drawback that the valve opening time cannot be controlled for a short period of time. In addition, when controlling the opening and closing of solenoid valves in synchronization with engine ignition, the magnetic flux decay time cannot be ignored compared to the maximum opening and closing synchronization, and the residual magnetic flux accumulates with each drive, resulting in a decrease in magnetic flux. Since the operating point is shifted to the saturation side, the utilization rate of the iron core is significantly reduced and the maximum drive frequency is significantly reduced1.
This problem can be solved if the iron core is made of a material with less magnetic aftereffect, such as ferrite material, but this material is not suitable for strength in solenoid valves that operate with impact7. In reality, the solution was to provide a solenoid valve for each cylinder of the engine to reduce the coverage area of each solenoid valve. 1, that is,
The discharge flow rate per solenoid valve is made small, and the minimum valve opening time is made long enough to ignore the valve opening delay due to magnetic flux attenuation. In addition, since a solenoid valve is provided for each cylinder, the drive interval is set at every ignition cycle for each cylinder (once every two revolutions in a 4-cycle engine), and the maximum drive frequency is kept within the usable range. This arrangement makes fuel control possible, but since a plurality of solenoid valves are used, the structure is complicated and expensive.

Next, with conventional systems that control the amount of fuel by the opening time of a solenoid valve, the range of fuel amount required by the engine is several tens of times larger, and moreover, high-precision control is required to comply with exhaust gas regulations. The valve opening time must be controlled with extremely high precision, taking into account the essential requirements. Therefore,
When the control device is configured with an analog circuit, it is essential to use high-precision parts and make complicated adjustments, and when the control circuit is configured with a microcomputer, it is necessary to use a microcomputer with a high-precision time control function. In either case, the control device becomes expensive1. Therefore, the object of the present invention is to eliminate the disadvantages of the conventional device and to provide a simple structure. The object of the present invention is to provide a fuel supply device that has high-speed response and enables highly accurate fuel metering. This will be explained in more detail.

FIG. 1 shows a fuel control system for an internal combustion engine to which the fuel supply system of the present invention is applied. This fuel control device is
An air amount sensor 6 installed in the intake pipe 2 connected to the intake port of the internal combustion engine 1, an intake temperature sensor 4 installed in the intake pipe 2 on the downstream side of the air amount sensor 6, and the intake temperature sensor 4 and a fuel supply device 3 having a fuel injection function, which is disposed downstream of a throttle valve 5 installed in an intake pipe 2 between the engine 1 and the engine 1. This fuel control device further receives output signals from the intake air amount sensor 6 and the intake temperature sensor 4, as well as an 02 sensor 8 attached to the exhaust pipe 7 that detects the oxygen partial pressure in the exhaust gas and evaluates the air-fuel ratio. 1. includes an arithmetic and control unit 11 that receives signals from an engine temperature sensor 9 attached to the engine body 1 and a primary voltage from an ignition coil 10 (for detecting engine speed). The 02 sensor 8 is a 1° first sensor located upstream of the catalytic converter 12 provided in the exhaust pipe 7.
The operation of the fuel control system shown in the figure will now be described.The engine 1 is controlled by a throttle valve 5, and sucks in an amount of air determined by the opening degree of the throttle valve 5 and the engine speed. This air amount is converted into an electrical signal by an air amount sensor 6. In the inclined fuel control system, a case will be described below in which this air amount is detected by a known Karman vortex type air amount sensor that detects the Karman vortex generation frequency. Although detailed description is omitted, as shown in Fig. 2, the air amount sensor 6
A pulse signal 3 with a frequency F proportional to the air amount QA is output. This output F is amplified by the control device 11 and drives the fuel supply device 3 in a pulse manner, so that the device 3 supplies a predetermined amount of fuel. Although the fuel supply device 3 is arranged downstream of the throttle valve 5 in FIG. 1, it may be installed so as to inject the fuel upstream.

A detailed explanation will be given later, but if the amount of fuel discharged by one pulse drive in the fuel supply device 3 is ΔV, then
The fuel iQF supplied to the engine per unit time is QF -Δ■・F-ΔV -K -QA-...-(1
), where K represents the input/output proportional constant of the air flow sensor 6. According to this equation (1), QvQF-1/
ΔV-, and fuel is supplied to the engine 1 while keeping the air-fuel ratio QA/QF at a predetermined value.12 Various parameters representing the operating state of the engine 1, that is, the output of the intake temperature sensor 4, 0. The output of the sensor 8, the engine temperature sensor 9, and the primary voltage of the ignition coil 10 are each input to the control device 11, which evaluates each parameter to calculate the voltage corresponding to the air-fuel ratio QA/QFK required by the engine, and calculates the fuel When the pulse height applied to the fuel supply device 3 changes, which is reflected in the pulse height that drives the supply device 3, the fuel amount ΔV discharged by one pulse drive changes, and therefore the air-fuel ratio QA/Qy -1/Δ■·K will be controlled to a value required by the engine.

The operation described above will be explained in more detail with reference to FIG. 3 showing one embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of the fuel supply device of the present invention. When attached to the pipe 2, the fuel injection nozzle 301 is fixed so as to enter into the intake pipe 2, as shown in FIG. A first fuel chamber 305 that directly communicates with the fuel injection nozzle 301 is formed by a diaphragm 303 whose side part is fixed and a partition wall 304 which supports the remaining side of the diaphragm. A space other than the fuel chamber 305 is a second fuel chamber 306 and communicates with a fuel inlet 307 formed in the wall of the casing 302.

A discharge valve 30 is provided at the tip opening of the fuel injection nozzle 301.
8 is arranged, and the discharge valve 308 is connected to the fuel injection nozzle 301.
It is connected to one end of the rond 309 that extends inward, and a splash plate 310 is attached to the other end. Then, the inner side of the tip of the fuel injection nozzle 301 and the presser plate 31
A coil spring 311 is contracted between the rod 309 and the rod 309. Therefore, the discharge valve 30
8 normally closes the tip opening of the fuel injection nozzle 301 by the elastic force of the coil spring 311. However, this coil spring 311 closes the tip opening of the fuel injection nozzle 301 by ΔP than the fuel pressure P+ in the first fuel chamber 305. The discharge valve 308 is set to operate to open the nozzle tip opening when the pressure is high.

On the other hand, a refueling opening is formed in the partition wall 304, and a pressure valve 312 is disposed in the opening. One end of a rod is connected to this pressure valve 312, and the second end of the rod is connected to the pressure valve 312.
extends toward the fuel chamber 306 side, and a spring holding plate 3 is attached to the other end.
13 are formed. And this spring holding plate 313
A coil spring 314 is contracted between the rod and the partition wall 304 so as to surround the rod, and the coil spring 314 opens the replenishment opening when the fuel pressure in the first fuel chamber 305 falls below P+. The pressure valve 312 is set to operate. .

A movable winding 315 is fixed to the center of the surface of the diaphragm 303 on the second fuel chamber 306 side, and the movable winding 315 is a magnetic circuit made of a permanent magnet fixed to the inner wall of the casing in the second fuel chamber 306. located in the gap of 316,
The winding is wound such that the axis of the winding is perpendicular to the magnetic flux generated in the gap. The movable winding 315 and the magnetic circuit 316 constitute an electric transducer that vibrates the diaphragm 303. .

Next, the operation of the fuel supply device 3 according to the embodiment shown in FIG. 3 will be explained.

The magnetic circuit 316 generates #1 approximately uniform magnetic flux B in the gap by the action of a permanent magnet. When a current i is passed through the movable winding 315 through terminals T+ and Tt, this movable winding 3
15, a force of f = B-i-ffi acts on it and tries to displace it in the X direction shown in Figure 3. However, the breath is the winding length of the movable winding 315 and is perpendicular to the magnetic flux. means the length of the current.

The displacement X is determined by the balance between the force f applied to the movable winding 315 and the reaction force of the diaphragm 303. In the configuration of this embodiment, only the reaction force of the diaphragm 303 is used as the equilibrium force, but it goes without saying that a spring can be provided separately and the reaction force of this spring can be used as the equilibrium force. Now, when the current i flowing through the terminals T, T, is interrupted in response to the pulse output of the air amount sensor 6 shown in FIG. 3. FIG. 4 is a waveform diagram for explaining the operation of the embodiment shown in FIG. 3. The operation of the embodiment will be further explained.

An intermittent current i with a frequency F is passed through the movable winding 315,
This current i causes a displacement X of the diaphragm 315 intermittently. When 1 displacement X occurs, the fuel in the first fuel chamber 305 is pressurized and the pressure rises, exceeding the set force of the spring 311, actuating the discharge valve 308 and opening the tip opening of the fuel injection nozzle 301. . The amount of fuel ΔV discharged from the opening of the nozzle 301 is approximately equal to the product of the displacement -m of the diaphragm 303 and the area S. Next, when the current id becomes zero and the displacement The differential pressure overcomes the set force of spring 314, actuating pressure valve 312 and opening the refueling opening. Thereby, fuel is replenished from the second fuel chamber 306 to the first fuel chamber 305 through this replenishment opening. By repeating this operation according to the interruption of the current i, ΔV-F is output from the fuel injection nozzle 301.
The fuel required by the engine is intermittently discharged, and the fuel required by the engine is supplied to the intake pipe. This shows that when the peak value of the current value i is increased as shown by the broken line, the force f generated increases accordingly, and therefore the displacement X also increases. As a result, the opening time of the fuel injection nozzle 301 by the discharge valve 308 becomes longer, and the discharged fuel ΔV increases.3 Therefore, when making the fuel rich, the current value i is increased, and conversely, when making the fuel lean, the current value i is increased. By reducing the amount, the air-fuel ratio can be controlled.

The average fuel pressure P1 in the first fuel chamber 305 is
11 and 314, but the diaphragm 3
It is obvious that it does not depend on the vibration frequency F and displacement X of 03, and by keeping the fuel inlet pressure Pa constant with a pressure regulator (not shown), stable fuel discharge is always performed. The second fuel chamber 306 is filled with fuel at a pressure Po, and the movable winding 315 is filled with the above-mentioned diaphragm 303.
In addition to the reaction force possessed by the fuel pressure difference (Ps Po), the reaction force due to the fuel pressure difference (Ps Po) is applied. Gene 311 and 31
By appropriately selecting the setting force in step 4, the fuel pressure P1 can be set to P.

If you take it as equal, then P+SaP. Since the reaction force due to this fuel pressure difference can be ignored, it is possible to reduce the force f required for the movable winding 315, that is, the current value i and the winding length l, thereby reducing the weight of the movable winding 3150. This makes it possible to increase the response speed of the diaphragm 303. However, the pressure Po
It is not the gist of the present invention to fill the second fuel chamber 306 with fuel, and the same function can be obtained even if the second fuel chamber 306 is opened to the atmosphere or into the intake pipe. It is a drawing showing another example of a mechanism that provides displacement, that is, an electric transducer. In the electric converter of this example, the peripheral edge of the diaphragm 303 has a cross section of an E-shaped core 317.
A fixed winding 318 is formed on the central protrusion of the core. In addition, the diaphragm 30
It forms part of the 3Fi magnetic path. Note that although this Fig. 5 only shows the electro-mechanical converter (electric converter) of the fuel supply device, other mechanisms such as the discharge valve and pressure valve are the same as in Fig. 3, so It is omitted in the figure. .

Next, to explain the operation of the electric converter shown in FIG.
When energized, the iron core 317 as a magnetic path and the diaphragm 303
and a magnetic flux is generated in the gap.

At this time, a force acts between the diaphragm 303 and the iron core 317 in the direction of shortening the gap length, thereby displacing the diaphragm 303 in the above-mentioned direction. When the amount of current is cut off, the diaphragm 30
3 returns to the original position.

In this way, the electric converter having the configuration shown in FIG. 5 can also ensure the normal operation of the fuel supply system of the present invention.
, FIG. 6 shows another example of an electric transducer that gives displacement to the diaphragm 303. 4. In the electric transducer in this example, a magnetostrictive iron core 319 having a U-shaped magnetostrictive characteristic is connected to the diaphragm 303. and a support 32 that supports the magnetostrictive core 319.
1, a spacer 320, and a fixed winding 318. FIG. 6 also shows only the electric converter, and other components as a fuel supply device, such as a discharge valve,
Pressure valves etc. are omitted.

According to the electric converter shown in FIG. 6, the terminals TI,
When a current is intermittently applied to the fixed winding 318 via T2, strain vibration occurs in the magnetostrictive core 319, and this vibration causes the diaphragm 3
Given to 03.

FIG. 7 shows an example of yet another electric transducer that gives displacement to a diaphragm 303.1 In this electric transducer, a diaphragm 303 having piezoelectric properties is used, and the central part of the front and back of the diaphragm is A first electrode 322 and a second electrode 323 are provided. According to such an electric converter, the first electrode 32
2 and the terminals TI+T! connected to the second electrode 323 via wires, respectively. Therefore, when a voltage is intermittently applied between these electrodes 322 and 323, the diaphragm 303 undergoes strain vibration.

In the above explanation, FIG. 3, FIG. 5, and FIG. 6 all show fuel supply devices of the type that intermittent the winding current, and in this case, the control device 11 of FIG. 1 is of the current output type. be done. On the other hand, FIG. 7 shows a fuel supply system in which the voltage is intermittent, and in this case, the control device 11 of FIG.
It will be easily understood that this is a voltage output type.

FIG. 8 shows another modification of the fuel supply mechanism in the fuel supply device 3 of the present invention. According to this refueling mechanism, a reed box-shaped pressure valve 324 is provided on the diaphragm 303, so there is no part like a partition wall in the device shown in FIG. 3, and the entire periphery of the diaphragm 303 is It is fixed to the inner wall of the casing 302 and divides the inside of the casing into a first fuel chamber 305 and a second fuel chamber 306. The rest of the configuration is similar to that of the device shown in FIG. 3, so it is omitted.

According to the fuel supply device 3 of the embodiment shown in FIG. 8, when the diaphragm 303 is displaced in the X direction, the first fuel chamber 30
5 fuel pressure increases. At this time, the pressure valve 324 is closed, and when the diaphragm 303 is displaced in the -X direction, it opens to replenish fuel from the second fuel chamber 306 to the first fuel chamber 305. The operation of the discharge valve 308 and pressure valve 324 in this case is similar to that of the embodiment of FIG.

In the embodiment shown in FIG.
The feature is that the fuel chamber structure is simplified by providing it on top of the fuel chamber.

Next, FIG. 9 shows still another embodiment of the present invention.

According to this embodiment, another nozzle is provided adjacent to the fuel injection nozzle 301, for a total of two nozzles 30.
1,301' is biased.

That is, the partition wall 325 that partitions the two fuel injection nozzles 301, 301' extends into the interior of the casing 302 and terminates at approximately the center of the interior chamber of the casing. On the other hand, in the lower part of the inner chamber of the casing on the side facing the partition wall 325, a partition wall 304 is disposed in cooperation with the casing 302 to completely close the inner chamber, and the outside of this partition wall 304 is used for fuel introduction. Passage 32 leading to mouth 307
It is said to be 6. As is clear from FIG. 9, the diaphragm 303 is attached so that the tl of the partition wall 325 divides the internal chamber of the casing between the vicinity of the terminal end and the partition wall 304, thereby allowing the fuel injection nozzle 301 to A first fuel chamber 305 communicating with the fuel injection nozzle 301' and a second fuel chamber 306 communicating with the fuel injection nozzle 301' are formed. Further, the partition wall 304 has the first fuel chamber 305 and the second fuel chamber 30.
Pressure valves 312 and 312' are located at the 6th and 6th positions, respectively.
is located. Each fuel injection nozzle 301, 301'
The constructions of the discharge valves 308, 308' and the respective pressure valves 312, 312' and the constructions of the springs and the like related thereto are the same as those in FIG. 3.

Further, although the electric transducer for vibrating the diaphragm 303 is omitted in FIG. 9, it is similar to that shown in FIG. 3 and other modifications. According to the fuel supply device w3, fuel is discharged at both the X-direction displacement position and the −X-direction displacement position of the diaphragm 303, making it possible to double the degree of discharge hassle, thereby improving the continuity of fuel injection. In addition to this, it also has the advantage of improving the efficiency of electro-mechanical conversion.

As explained above, in the fuel supply device of the present invention, fuel is supplied by vibration of the diaphragm, and a large amount of fuel is discharged according to the volume change Δ■ generated in the fuel chamber. The amount of fuel to be discharged is determined by the product of the volume change ΔV and the driving frequency F, and is adjusted to the amount of fuel required by the engine by adjusting either ΔV or F. The upper limit of the frequency F is determined by the response of the electromechanical converter, that is, the electric converter, but it is considerably improved compared to the conventional solenoid valve.In other words, in the embodiment shown in FIG. The magnetization is always constant, and there is no deterioration in response due to the delay in magnetic flux decay1.
In the embodiments shown in FIG. 6 and FIG. 6, since no impact is applied to the iron core, a ferrite-based material with small magnetic aftereffect can be used, so that almost no deterioration in response due to magnetic flux decay delay is observed. Furthermore, in the embodiment shown in FIG. 7, extremely excellent response can be achieved because a piezoelectric material is used.Furthermore, in both embodiments, fuel is placed at approximately the same pressure before and after the diaphragm. Since it is full, the braking force due to fuel pressure is canceled out, which has a great effect on improving responsiveness.

Furthermore, in the embodiment shown in FIG. 9, the fuel is discharged by the reciprocating motion of the diaphragm, so the drive frequency is isometrically doubled and the effect of speeding up is significantly increased. In this way, the present invention has great effects because it is possible to supply fuel with one fuel supply device over the drive frequency range required by the engine.

Next, since the fuel amount is adjusted by controlling the amount of fuel ΔV discharged per vibration of the diaphragm, that is, the amplitude of the diaphragm, a highly accurate time control function is required. First, the control device can be configured with many inexpensive elements. In particular, when the fuel supply device is driven in synchronization with the output frequency F of the Karman vortex air amount sensor cited in the description of the present invention, fuel proportional to the air amount is supplied as shown in equation (1). Therefore, ΔV only needs to be controlled within a range that is only several times the air-fuel ratio range required by various engine parameters.Therefore, the amplitude range of the drive signal output by the control device is small, and the main The ripple effect of inventions is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a fuel control device using the fuel supply device of the present invention, FIG. 2 is a diagram showing the output characteristics of an air amount sensor which is a component of the fuel control device in FIG. 1, and FIG. 4 is a sectional view showing one embodiment of the fuel supply device of the present invention.
The figures are waveform diagrams showing the current, displacement, discharge valve, and pressure valve operating states during operation of the fuel supply system in Figure 3, and Figure 5.
FIGS. 6 and 7 are partial cross-sectional views showing different embodiments of the fuel supply device of the present invention, each showing a modified example of an electric transducer that vibrates a diaphragm, and FIGS. 8 and 9 are 3 is a cross-sectional view schematically showing still another embodiment of the fuel supply device of the present invention, 1... internal combustion engine, 2... intake pipe, 3... fuel supply device, 11... control Device, 301, 301'...
Fuel injection nozzle, 302...Casing, 303...
・Vibration plate, 305... @1 fuel chamber, 306... Second fuel chamber, 308° 308'... Discharge valve, 312
, 312'...pressure valve, 315...movable winding, 31
6... Permanent magnet, 317... Iron core, 318... Fixed winding, 319... Magnetostrictive iron core, 322° 323...
electrode. In addition, the same reference numerals in the drawings indicate the same or corresponding parts.
Fig. 3 I3 5sr Fig. 6 Fig. 7 Cause 8 Fig. Effect J Teeth

Claims (1)

[Scope of Claims] (1) A fuel chamber formed by a vibrating diaphragm as a part of a partition wall, and an electric transducer connected to the diaphragm and vibrating the diaphragm based on an electrical signal; A fuel injection nozzle is provided on a casing that partitions the fuel chamber and operates a discharge valve to open and discharge fuel when fuel pressure increases; a fuel supply device 5 that includes a pressure valve that replenishes fuel to the fuel chamber as the pressure decreases, and intermittently discharges fuel by vibration of the diaphragm (2. The fuel supply device according to claim 1); A fuel supply device capable of controlling the amount of fuel discharged by one vibration by making the amplitude of the diaphragm variable by controlling the amplitude of an electric signal. (3) Claims 1 and 2. In the fuel supply device according to item 2, the fuel supply device 5 is characterized in that a second fuel chamber is provided on the back side of the diaphragm to reduce the reaction force due to the fuel pressure that the diaphragm receives. In the fuel supply device according to claim 3, the wall forming the second fuel chamber also includes a fuel injection nozzle that operates a discharge valve to open and discharge fuel due to an increase in fuel pressure. a pressure valve is provided for replenishing the second fuel chamber with fuel due to a decrease in pressure;
A fuel supply device that discharges fuel during both forward and backward movement of the diaphragm. (5) In the fuel supply device according to any one of claims 1 to 4, the electric converter is constituted by a permanent magnet or a composite of a permanent magnet and a magnetic material, and a gap, and the electric converter has a substantially uniform shape in the gap. A fuel supply device 6° (6) comprising a magnetic circuit that generates magnetic flux and a movable winding arranged in the gap so that its axis is perpendicular to the magnetic flux and fixed to the diaphragm. In the fuel supply device according to any of Items 1 to 4, the electric converter faces a winding having an iron core made of a magnetic material or a composite of a magnetic material and a permanent magnet, with a gap interposed therebetween. 1. A fuel supply device comprising: a diaphragm forming a part of a magnetic path; (7) In the fuel supply device according to any one of claims 1 to 4, the electric converter is constituted by an iron core having magnetostrictive characteristics and a winding wound around the iron core. Fuel supply device 7, (8) In the fuel supply device according to claims 1 to 4, the electric transducer is a piezoelectric diaphragm in which electrodes are formed on both sides of a ceramic plate having piezoelectric properties, or A fuel supply device comprising a piezoelectric diaphragm in which the piezoelectric diaphragm is laminated in multiple layers.