JPH0423592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates generally to ultrasonic injection technology for atomizing liquid substances, and particularly to internal combustion engines such as diesel engines and gasoline engines, or burners, etc. A vibrator used in an ultrasonic injection nozzle that atomizes liquid substances intermittently or continuously, and is suitable for use in fuel injection valves of external combustion engines, as well as drying injection devices for manufacturing powdered chemicals. It is related to.

In this way, the present invention is applicable to liquid substances (herein, "liquid substance" is used to include not only liquids such as liquid fuels but also solutions such as liquids for manufacturing drugs). ) is atomized,
Although it may be used as an oscillator for an injector nozzle or an injection device, the invention will be described hereinafter in particular in connection with an oscillator for a fuel injection nozzle for internal combustion engines, such as diesel engines and gasoline engines.

Conventional Technologies and Problems Conventionally, various attempts have been made to supply atomized liquid fuel to the combustion chamber or pre-combustion chamber in order to reduce soot and improve fuel efficiency in internal combustion engines such as diesel engines and gasoline engines. There is. The most common method is to inject liquid fuel at high pressure from the injection port of an injection nozzle, but at this time, atomization of the liquid fuel is promoted by applying ultrasonic vibrations to the liquid fuel. It has been known.

Conventionally, two types of atomization mechanisms for liquid using ultrasonic waves have been considered: a single cavitation mechanism and a two-wave mechanism.The cavitation mechanism is difficult to control the degree of atomization, so Application to valves is not appropriate. There are two types of wave mechanisms: capillary type and liquid thin film type. According to the capillary type, pores are formed in the ultrasonic vibrator, liquid fuel is supplied from the pore entrance, and at the same time the ultrasonic vibrator Vibrated. As a result, the liquid fuel spreads from the pore outlet to the lower surface of the vibrator in the form of a film, and is then injected as a mist. On the other hand, according to the liquid thin film method, the tip of the ultrasonic vibrator is formed to have a widened surface portion, for example, in the shape of a poppet valve, and liquid fuel is supplied to the surface portion. The liquid fuel spreads in a thin film on the surface of the ultrasonic transducer, and then is injected as a mist.

As can be understood from the above explanation, the mechanism of atomization of liquid by conventional ultrasonic vibration is thought to be due to cavitation or wave motion after the liquid becomes a thin film, and in particular, large amounts of atomization are due to thin film wave motion. was considered essential, and the above-mentioned configuration was proposed.

However, the injection nozzles that have been proposed so far have extremely small amounts of atomized fuel, and currently cannot be used as injection nozzles for internal combustion engines such as diesel engines and gasoline engines that require large volumes of atomized fuel. Ta.

In order to achieve atomization of a large volume of liquid fuel, the present inventors conducted numerous studies and experiments on the liquid atomization mechanism using ultrasonic waves and the shape of ultrasonic vibrators, and as a result, the above-mentioned atomization was achieved. It has been found that atomization of liquid fuel is achieved by a different atomization mechanism. That is, the present inventors formed an edge portion at the end of the ultrasonic transducer,
It has been found that by supplying liquid fuel in the form of a thin film to the edge, a large amount of liquid fuel can be atomized from the edge.

The present invention relates to the shape of an ultrasonic vibrator for realizing such a novel ultrasonic injection method and apparatus.

OBJECTS OF THE INVENTION The main object of the present invention is to provide a vibrator for an ultrasonic jet nozzle that can atomize a large volume of liquid material intermittently or continuously.

Another object of the present invention is to provide a vibrator for an ultrasonic injection nozzle that achieves atomization of various liquid substances including liquid fuel and enables stable atomization regardless of the properties of the liquid substance. It is.

Still another object of the present invention is to atomize liquid fuel uniformly and in large quantities, to achieve complete fuel production in a short period of time, and to achieve soot-free internal combustion engines such as diesel engines and gasoline engines with improved fuel efficiency. An object of the present invention is to provide a vibrator for an ultrasonic injection nozzle for use in or for an external combustion engine.

Another object of the present invention is to simultaneously achieve large-capacity atomization,
It is an object of the present invention to provide a vibrator for an ultrasonic injection nozzle for an internal combustion engine with good fuel efficiency, which enables atomization at low flow rates, which has conventionally been difficult to atomize.

Still another object of the present invention is to provide a vibrator for an ultrasonic injection nozzle for an internal combustion engine, which can reduce soot and improve fuel efficiency, is extremely practical, and can be used continuously for a long time. It is to be.

Still another object of the present invention is to provide a vibrator for an ultrasonic injection nozzle that can perform fuel injection without time delay.

Still another object of the present invention is to provide a vibrator for an ultrasonic jet nozzle suitable for spraying a chemical manufacturing solution such as a chemical powder and drying the contained substance.

Still another object of the present invention is to provide an ultrasonic vibrator that realizes an ultrasonic jet nozzle that can have a compact structure.

Means for Solving the Problems The above objects are achieved by the vibrator for an ultrasonic jet nozzle according to the present invention. In summary, the present invention is a vibrator for an ultrasonic jet nozzle, which forms at least two multistage edge portions on the outer periphery, supplies a liquid substance to the edge portions, and atomizes the liquid substance. . Preferably, the multi-stepped edge portion is formed so that the diameter thereof gradually decreases.

EXAMPLE Next, an example of an ultrasonic jet nozzle that can use the vibrator according to the present invention will be illustrated, and the vibrator according to the present invention will be explained in more detail.

Although the ultrasonic injection nozzle vibrator according to the present invention can be suitably used in injection nozzles for various purposes as described above, in this embodiment, the present invention will be explained in relation to a liquid fuel injection nozzle for an internal combustion engine. .

Referring to FIG. 1, the ultrasonic jet nozzle 1 is
It includes an elongated, generally cylindrical housing 4 having a central hole 2 at its center. A lower mounting portion 10 of the transducer holder 8 is attached to the upper outer peripheral screw portion 6 of the housing 4.
are screwed together. A through hole 12 is formed in the center of the vibrator holder 8 . The through hole 12 is formed in alignment with the center hole 2 of the housing 4 in the longitudinal direction, that is, coaxially therewith.

Through hole 12 of vibrator holder 8 and housing 4
A vibrator 14 formed according to the present invention is placed through the central hole 2 of the oscilloscope. The vibrator 14 includes an upper body portion 16, an elongated cylindrical vibrator shaft portion 18 having a smaller diameter than the body portion 16, and the body portion 16 and the shaft portion 18.
It consists of a transition section 20 that connects the two. Main body part 16
has a tsuba 22 with a larger diameter, and the tsuba 22
However, an annular shoulder 24 formed on the inner circumference of the upper end of the transducer holder 8 and a bolt 2 on the upper end surface of the transducer holder 8
An annular vibrator holder 30 attached by 8
It is attached to the vibrator holder 8 by.

The shaft portion 18 of the vibrator 14 further protrudes below the housing 4, that is, further outward. Vibrator 1
4, that is, the tip of the shaft portion 18, an edge portion 32, which will be described in detail later, is formed. Vibrator 14
A hollow needle valve 3 is installed in the part protruding from the housing 4.
4 is slidably fitted.

The hollow needle valve 34 has a generally cylindrical shape, and includes a reduced diameter portion 36 at the upper end, a large diameter portion 38 at the center, an inclined portion 40 formed at an angle from the large diameter portion 38, and the inclined portion 40.
It is composed of a small diameter part 42 connected to the small diameter part 42, and an inclined tip part 44 formed to be inclined from the small diameter part 42. The tip end of the inclined tip portion 44 is formed to be located close to the edge portion 32 of the vibrator 14 . On the other hand, the upper end reduced diameter portion 36 of the hollow needle valve 34
extends further upwardly than an annular shoulder 46 formed at the lower end of the housing 4 so as to project inwardly.

The hollow needle valve 34 is housed in a hollow needle valve holder 50, and the hollow needle valve holder 50 is removably fixed to the housing 4 by a holder cover 52 attached to the outer periphery of the holder 50. The inner peripheral shape of the hollow needle valve holder 50 includes a large diameter hole 54 into which the central large diameter portion 38 of the hollow needle valve 34 slides, and an inclined portion 56 having a complementary shape to the inclined portion 40 of the hollow needle valve 34. , a large-diameter hole portion 58 , and an inclined tip portion 60 . The small diameter hole 58 and the angled tip 60 cooperate with the small diameter section 42 and the angled tip 44 of the hollow needle valve 34 to form a liquid fuel supply passage 62 .

An annular fuel reservoir 64 that opens inward is formed in the inclined portion 56 of the hollow needle valve holder 50 . The fuel reservoir 64 communicates with a fuel supply passage 66 bored within the hollow needle valve holder 50. Further, the fuel supply passage 66 communicates with a fuel introduction passage 68 bored in the housing 4. The fuel introduction path 68 is connected to the housing 4
The fuel inlet port 70 of the fuel inlet port 70 of FIG.

On the other hand, an inwardly opened annular fuel return reservoir 7 is located above the large diameter hole 54 of the hollow needle valve holder 50.
2 is formed. The fuel return reservoir 72 is also connected to a fuel outlet port 78 via a fuel return passage 74 and a fuel exhaust passage 76 drilled through the hollow needle valve holder 50 and housing 4.

A compression spring 80 is disposed in an annular space formed by the center hole 2 of the housing 4 and the vibrator shaft portion 18 . The lower end of the compression spring 80 contacts the upper end surface of the upper end reduced diameter portion 36 of the hollow needle valve 34 via the annular spring receiver 82, and the upper end contacts the lower end surface of the injection pressure adjusting member 84. The injection pressure adjustment member 84 is a cylindrical member disposed in a space formed by the center hole 2 of the housing 4 and the vibrator shaft portion 18, and is screwed into the inner peripheral portion of the upper end of the housing 4. Ru. Therefore, by rotating the injection pressure adjustment member 84 with respect to the housing 4, the pressing force against the hollow needle valve 34 can be adjusted.

Next, the operation of the ultrasonic jet nozzle 1 having the above configuration will be explained.

In operation, liquid fuel is supplied to the fuel inlet port 70.
will be introduced. Liquid fuel is supplied to the fuel reservoir 64 through a fuel introduction passage 68 and a fuel supply passage 66. The fuel reservoir 64 is closed by the ramp 40 of the hollow needle valve 34, which is pressed downwardly by a spring 80. Therefore, the pressure within the fuel reservoir 64 increases with the continuous supply of liquid fuel. When the pressure within the fuel reservoir 64 reaches a certain level, it causes the hollow needle valve 34 to move upwardly against the force of the spring 80.

The upward movement of the hollow needle valve 34 opens the fuel reservoir 64 to the liquid fuel passage 62, which is supplied with liquid fuel. The fuel passing through the liquid fuel passage 62 is supplied to the edge portion 32 formed at the tip of the vibrator 14.

The edge portion 32 of the vibrator 14 is preferably
As shown in the figure, the diameter of the 3
It can also be shaped like a concentric staircase consisting of steps,
2 or 5 stages as shown in Figures 2 and 3.
It is also possible to have a stepped shape. Whatever the shape, it is important that edges are formed around the outer periphery. Edge portion 3 shown in FIGS. 1 to 3
2 is said to have a step-like shape whose diameter is gradually reduced,
It is also possible to have a shape in which the diameter gradually increases, or the diameter gradually decreases and then increases.

Further, as shown in FIG. 4, the width W and height h of the edge are dimensioned to form a thin film of the liquid fuel and to block the flow of the liquid.

The vibrator 14 is continuously vibrated by an ultrasonic vibration generating means 100 operatively connected to the main body 16 . Therefore, when liquid fuel is supplied to the edge portion 32 of the vibrator 14, the liquid fuel is atomized and injected outward. To explain further, when liquid fuel is supplied to the edge portions, the flow of fuel is cut off at each edge portion due to the longitudinal vibration applied to the vibrator 14, and the supplied fuel is atomized. A portion of the fuel is first atomized at the edge of the first stage, and excess fuel that cannot be processed by the edge of the first stage is sent to the edge of the second stage and the third stage. , processed at each edge. Therefore, when the fuel flow rate is large, the effective area required for atomization becomes large and multiple stages of edges are required, but when the fuel flow rate is low, atomization is completed without using multiple stages. Therefore, in the vibrator 14 according to the present invention, when the flow rate changes, the number of stages required for atomization changes, and conditions such as the liquid film thickness at the position where atomization is performed are approximately the same at each stage. The resulting droplet size becomes uniform. According to this vibrator, all the flow rates normally required for atomization can be covered, so liquid substances with various properties can be atomized regardless of whether the atomization is intermittent or continuous.

In this embodiment, when injecting the atomized liquid as described above, it is important to eliminate unevenness of the injection and to inject uniformly around the injection nozzle.As shown in FIG. A plurality of inclined grooves 43 are formed in the small diameter part, for example, two grooves 43 are arranged diametrically opposite each other.
It has been found that by forming this, turbulence is generated within the fuel supply passage, giving swirl to the injected fuel, thereby eliminating uneven injection. Moreover, such a structure can improve the sharpness of the injection and the atomization of the particles.

One specific condition and dimensions of the ultrasonic jet nozzle described above are as follows.

●Output of ultrasonic vibration generating means: 10w ●Amplitude of vibrator: 30μm Frequency: 38KHz ●Shape and dimensions of vibrator 1st stage: 7mm diameter 2nd stage: 6mm diameter 3rd stage: 5mm diameter Height of each stage (h) : 1.5mm ●Fuel type: Light oil Flow rate: ^0.06cm3 /injection Injection pressure: 70Kg/ ^{cm3Temperature} : Room temperature ●Vibrator material: Titanium (or iron) (Note) The amplitude of the vibrator should be as large as possible is good.

The frequency of the vibrator is made greater than 20KHz.

The fuel injection pressure should be close to the engine room pressure.

A part (surplus portion) of the liquid fuel supplied to the fuel reservoir 64 passes through a minute gap (μm order) between the hollow needle valve 34 and the hollow needle valve holder 50 and is stored in the fuel return reservoir 72. Fuel return passages 74 and 7
6 and returned to the fuel outlet 78. Fuel outlet 78 communicates with the tank by a suitable conduit (not shown) so that excess fuel is returned to the tank.

When the pressure in the fuel reservoir 64 decreases, the spring 80
The force causes the hollow needle valve 34 to move downward, closing the fuel reservoir 64 and cutting off the fuel supply to the edge 32 of the vibrator 14. Therefore, injection nozzle 1
Fuel injection from will stop.

In the injection nozzle having the above configuration, the vibrator 14
can be kept in a constant operating state regardless of fuel supply, thereby avoiding deviations in fuel injection timing due to deviations in the start of vibration.

Furthermore, the injection nozzle using the vibrator according to the present invention can achieve a large capacity of 0.06 cm ² /injection, which is practical as an injection nozzle for an internal combustion engine, which is higher than conventional reports. The flow rate is 500 to 1000 times that of the ultrasonic injection nozzle. Furthermore, the oscillator of the present invention can be used as a oscillator for a continuous combustion burner, and the flow rate at this time is 100%.
/hr. The present invention can also be used in a drying injection device for powdering chemicals.

Effects of the Invention As explained above, the vibrator according to the present invention has
It is possible to atomize a large volume of liquid continuously and intermittently, and the atomization distribution of the liquid is approximately uniform regardless of whether the volume is large or small, and the average particle size is 10 to 10.
It is possible to achieve stable atomization of about 30 μm, regardless of the properties of the liquid substance. In particular, when the vibrator according to the present invention is used, liquid fuel can be atomized uniformly and in large quantities, and complete fuel can be achieved in a short period of time. An ultrasonic injection nozzle for internal combustion engines or for external combustion engines such as burners can be realized very advantageously.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of an embodiment of an ultrasonic jet nozzle using a vibrator according to the present invention. FIGS. 2 and 3 are partial front views showing other aspects of the tip edge portion of the vibrator according to the present invention. Fourth
The figure is a partially enlarged operational view of the edge portion. FIG. 5 is a front view of the hollow needle valve. 1: Injection valve, 4: Valve box, 8: Vibrator holder, 1
4: Vibrator, 32: Edge part, 34: Hollow needle valve,
50: Hollow needle valve holder.

Claims (1)

[Scope of Claims] 1. Ultrasonic waves that are provided with at least two multi-stage edge portions on the outer periphery to receive liquid substances and atomize the liquid substances, and that are ultrasonically vibrated by ultrasonic vibration generating means. Vibrator for injection nozzle. 2. The vibrator for an ultrasonic jet nozzle according to claim 1, wherein the multi-stage edge portion is formed so that the diameter thereof gradually decreases.