JPH033959A - Ultrasonic atomizer for alcohol engine - Google Patents

Abstract

PURPOSE:To make the spray angle adequate regardless of the quantity of the fed fuel and obtain a uniform peripheral spray by forming a slant face section and a shrunk section smaller than the slant face section in diameter at the tip of a vibrator horn, and arranging the opening section of a sleeve oppositely to the slant face section. CONSTITUTION:Alcohol fuel passes a peripheral groove 5b, a passage 9a, a slant passage 9b and an opening section 9c respectively and reaches an atomization face 4. The alcohol fuel is fed to the opening section 9c and the whole periphery of the slant face section of a vibrator horn 10 through the whole periphery of the peripheral groove 5b, and the alcohol fuel is made nearly uniformly thick in this process and reaches the slant face section. The fuel reaching the slant face section is atomized by the ultrasonic vibration from a ultrasonic vibration generator 2, the fuel not atomized here smoothly flows from the slant face section to a small-diameter shrunk section, and the whole quantity is atomized here and sprayed at the preset spray angle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic atomization device in a spark ignition engine using alcohol fuel.

[Prior Art] 10% of alcohol, methanol or ethanol
Spark ignition engines that use 0% fuel or alcohol Φ gasoline mixed fuel with alcohol content of 50% or more have difficulty starting the engine because the boiling point of alcohol is higher than that of gasoline and the latent heat of vaporization is also large. It has the following drawbacks.

Therefore, in Japanese Patent Application Laid-Open No. 57-153964, an ultrasonic vibration type spray nozzle and a surface heating element are installed in the engine intake pipe to reflect the spray from the nozzle and turn it into a fine mist. A method has been proposed in which alcohol is atomized using an ultrasonic vibrating spray nozzle and a surface heating element, and alcohol fuel is supplied via a vaporizer after the engine is started.

[Problem to be solved by the invention]

However, in the above-mentioned conventional system, an ultrasonic spray nozzle and a surface heating element must be specially provided for the start-up with a low degree of brightness, resulting in an increase in cost. The present invention solves this problem by:
We propose to improve the startability of alcohol engines by simply adopting an ultrasonic atomizer without using a vaporizer, but this cannot be achieved with conventional ultrasonic atomizers. Ta.

A conventional ultrasonic atomization device will be explained with reference to FIGS. 5 and 6.

FIG.
2. Consisting of a vibrator horn 103 and an electric/acoustic transducer 104, a fuel supply passage 105 is formed in the cylinder 101, and an injection hole 106 communicating with the fuel supply passage 105 is formed in the nozzle body 102. There is. The injection hole 106 is
A plurality of injection holes 10 are formed on the circumference of the nozzle body 102.
The fuel injected from 6 is supplied to the vibrator horn 103 to atomize the fuel.

Furthermore, FIG. 6 shows an annular type ultrasonic injection valve that supplies liquid to the atomizing surface from a plurality of holes, and the outer cylinder 111
, an inner cylinder 112, a vibrator horn 113, an electric Φ acoustic transducer 114, and an outer cylinder 11.
A fuel supply path 115 is formed between the outer cylinder 111 and the inner cylinder 112, and fuel is supplied from the entire circumference of the outer cylinder 111 to the vibrator horn 113 to atomize the fuel.

By the way, in alcohol engines, in order to ensure good atomization efficiency over a wide fuel supply range,
It is essential to uniformly form a thin film of liquid on the atomizing surface of the vibrator. Furthermore, in order to atomize the entire amount of the supplied fuel, it is important that the supplied fuel is not blown away on the atomization surface even if the speed of the supplied fuel becomes high.

However, in the above-mentioned multi-hole ultrasonic injection valve, the amount of atomization is determined by the amount supplied from the injection hole 106, so the turndown ratio, which indicates the ratio between the maximum amount of atomization and the minimum amount of atomization, is large. , and when it is placed horizontally, the injection hole 108
The problem is that it is difficult to evenly distribute the liquid between the two, resulting in non-uniform spraying. Furthermore, there is a limit to increasing the number of injection holes 10B in order to uniformly distribute the fuel, and there is also the problem that machining of the injection holes 106 is difficult and manufacturing costs increase.

Furthermore, in the annular type ultrasonic injection valve, the amount of atomization is determined by the clearance 116 between the tip of the outer cylinder 111 and the vibrator horn 113. The problem is that mounting accuracy is required, which increases manufacturing costs. Furthermore, if the accuracy of the clearance 116 is low, there are problems in that a large turndown ratio cannot be obtained and the spray becomes non-uniform.

Furthermore, the conventional system described above has a problem in that the spray angle of the atomized fuel by the ultrasonic injection valve becomes large, and the fuel adheres to the inner wall of the intake pipe, which has a relatively small diameter.

An object of the present invention is to solve the above-mentioned problems and problems, and by improving the shape of the tip of the vibrator of an ultrasonic injection valve, it is possible to make the spray angle appropriate regardless of the amount of fuel supplied, and to It is an object of the present invention to provide an ultrasonic atomization device that has a large turndown ratio and can obtain uniform all-round spraying.

By the way, in this type of ultrasonic injection valve, in order to ensure good atomization efficiency over a wide fuel supply range, it is essential to uniformly form a thin film of liquid on the atomization surface of the vibrator. . Furthermore, in order to atomize the entire amount of the supplied fuel, it is important that the supplied fuel is not blown away on the atomization surface even if the speed of the supplied fuel becomes high.

However, in the above-mentioned multi-hole ultrasonic injection valve, the amount of atomization is determined by the amount supplied from the injection hole 106, so the turndown ratio, which indicates the ratio between the maximum amount of atomization and the minimum amount of atomization, cannot be set large. , when placed horizontally, the injection hole 106
The problem is that it is difficult to distribute the liquid evenly, resulting in uneven spraying. Furthermore, there is a limit to increasing the number of injection holes 10Ei in order to uniformly distribute the fuel, and there is also the problem that machining of the injection holes 108 is difficult and manufacturing costs increase.

Furthermore, in the annular type ultrasonic injection valve, since the amount of atomization is determined by the clearance 116 between the tip of the outer cylinder 111 and the vibrator horn 113, the flange of the outer cylinder 111 and the vibrator horn 113 113a is required, resulting in an increase in manufacturing costs. Furthermore, if the accuracy of the clearance 116 is low, there are problems in that the turndown ratio is too large (and cannot be achieved) and the spray becomes non-uniform.

Furthermore, in the above-mentioned conventional system, the spray angle of the atomized fuel by the ultrasonic injection valve becomes large, leading to the problem that the fuel adheres to the inner wall of the intake pipe, which has a relatively small diameter.

An object of the present invention is to solve the above-mentioned problems and problems, and to improve the startability of an alcohol engine by simply employing an ultrasonic atomizer without using a carburetor.

Another object of the present invention is to improve the shape of the tip of the vibrator of the sonic injector, so that the spray angle can be made appropriate regardless of the amount of fuel supplied, and the turndown ratio can be increased to achieve uniform overall spraying. An object of the present invention is to provide an ultrasonic injection valve capable of producing circumferential spray.

[Means to solve the problem]

To this end, the ultrasonic atomizer for an alcohol engine of the present invention includes a vibrator horn 10 disposed in an intake pipe for atomizing alcohol fuel, and a vibrator horn 10 disposed around the outer circumference of the vibrator horn 10 to atomize alcohol fuel. a sleeve 9 for supplying fuel over the circumference of the vibrator horn 1;
0 is characterized in that an inclined surface portion 10b and a reduced diameter portion 10c are formed at the tip thereof, and an opening portion 9C of the sleeve is disposed opposite to the inclined surface portion 10b.

Note that the numbers added to the above configurations are for comparison with the drawings, and the configurations of the present invention are not limited thereby.

[Effect]

In the present invention, for example, as shown in FIGS. 1 and 2, the alcohol fuel is
The slanted passage 9b1 passes through the opening 9c and reaches the atomization surface 4. At this time, the alcohol fuel passes through the entire circumference of the circumferential groove 5b and is supplied to the entire circumference of the opening 9C and the inclined surface portion 10b, so that in the process, the alcohol fuel is distributed to a generally uniform film thickness. The inclined surface portion 10
Reach b. The fuel that has reached the inclined surface portion 10b is atomized by the ultrasonic vibrations from the ultrasonic vibration generator 2, and the fuel that cannot be atomized here smoothly flows to the reduced diameter portion 10c where the entire amount is It will be atomized and sprayed at a spray angle α.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of essential parts showing one embodiment of the ultrasonic injection valve of the present invention, FIG. 2 is an overall sectional view showing one embodiment of the ultrasonic injection valve of the present invention, and FIG. FIG. 4 is a cross-sectional view of an alcohol engine using an ultrasonic atomizer.

In Fig. 4, 21 is a cylinder, 22 is a connecting rod,
23 is a piston, 24 is a combustion chamber, 25 is an intake pipe, 26 is an intake valve, 27 is an exhaust pipe, and 28 is an exhaust valve. Intake pipe 2
At predetermined positions of 5, an ultrasonic atomizer 29 and a fuel injection valve 3 are installed.
A mounting body 31 to which the ultrasonic atomizer 2 is fixed is provided.
A vibrator 32 provided at the tip of the intake valve 9 is disposed facing the intake valve 26. Then, alcohol fuel is supplied from the fuel supply path 33 of the fuel injection valve 30 to the vibrator 32, where the fuel is atomized and sprayed into the intake pipe 25.

2 and 3, the ultrasonic atomization device 1 of the present invention is equipped with an ultrasonic vibration generating section 2 for emitting ultrasonic vibrations at the base, and this ultrasonic vibration generating section 2 includes a vibrator. The shaft portion 3 and the vibrator horn 10 are connected, and an atomizing surface 4 is formed at the tip thereof.

A substantially annular sleeve member 5 is disposed on the outer circumference of the vibrator shaft portion 3 so as to surround it, and the outer circumference of the tip portion 5a of the sleeve member 5 has a diameter slightly larger than the outer diameter of the tip portion 5a. A ring cane casing member 6 having a large inner diameter is fixed,
A sleeve 9 is formed between the tip portion 5a of the sleeve member 5 and the casing member 6. Furthermore, the sleeve member 5
The distal end portion of the casing member 6 is tapered, and therefore, an annular passage 9a1 is formed between the outer circumferential surface of the distal end portion 5a of the sleeve member 5 and the inner circumferential surface of the casing member 6.
An inclined passage 9b and an opening 9C are formed. The sleeve member 5 is provided with a circumferential groove 5b at a suitable position on its outer peripheral surface over the entire circumference in the radial direction, and the casing member 6 is provided with a fuel supply port 6a at a suitable position. This fuel supply port 6a communicates with the circumferential groove 5b and the passage 9a.

Alcohol fuel is supplied from a fuel injection valve to the fuel supply port 6a of the casing member 6, and is supplied over the entire circumference of the circumferential groove 5b of the sleeve member 5.

The fuel supplied to the circumferential groove 5b passes through the passage 9as and the inclined passage 9b, reaches the opening 9c, and reaches the atomization surface 4. The fuel that has reached the atomization surface 4 is atomized by ultrasonic vibrations from the ultrasonic vibration generator 2 .

FIG. 1 is a sectional view showing the shapes of the tips of the sleeve 9 and the vibrator horn 10 of the ultrasonic atomizer 1. As shown in FIG. At the tip of the vibrator horn 10, an enlarged diameter portion 10a1 and an inclined surface portion 10 are provided.
b and a reduced diameter portion 10c are formed. Said enlarged diameter part 1
0a functions to increase the atomization area. One of the features of the vibrator horn 10 of the present invention is that it is provided with an enlarged diameter portion 10a, but this is to ensure the effect of increasing the flow rate of the injected liquid, and there is no need to ensure a large flow rate. In this case, there is no particular need to provide the enlarged diameter portion 10a, and there is no problem in providing the enlarged diameter portion 10a.

An example of the dimensions of each part is shown below. In addition, the vibrator horn 1
The diameter of the enlarged diameter portion 10a of 0 is D=9㎜, the inclined surface portion 10b
Let the axial length of be l, :O, Smm. L/D is 1/
It is 10 to 1/30, preferably about 1/18.

■The spray angle α is 30° to 45°. The reason for this is that when an ultrasonic atomizer is installed in an engine, it is important to set the spray angle so that the fuel does not adhere to the inner wall of the intake pipe, but it is also important to set the spray angle to a certain degree to improve the mixing effect with the air. This is because it is necessary.

(2) The angle β between the tip of the sleeve 9 and the inclined surface portion 10b is between 5'' and 45°, preferably about 15°, which is an angle at which the atomized fuel is not blown away and easily rides on the atomizing surface.

■The angle γ of the reduced diameter portion 10c with respect to the axial center is 0° to 90°.
'', preferably 40' to 50''. Figure 1(b)
(C) shows an example where γ=90°, and (C) shows an example where γ=0°. The spray angle α becomes wider as the angle γ becomes smaller, and becomes narrower as the angle γ becomes larger.

■The upper and lower limits of the distance between the opening 9C of the sleeve 9 and the enlarged diameter portion 10a of the vibrator horn 10 are 0.05■I
~0,51■, preferably 0.1m-~0.2mm (D
+/D=0, O1~0.02). The reason for this is that below the lower limit, the distance between the tip of the sleeve 9 and the vibrator horn 10 is too narrow and there is a risk that they may come into contact with each other.
It falls off without reaching surface b.

■The distance between the opening 9C of the sleeve 9 and the enlarged diameter part 9a is 0 to 0.51■ (L + / L = O~). 10a, the liquid film tends to form (and the reduced diameter part 1
When it is moved to the 0c side, the incident angle becomes negative, and the liquid penetrates through.

FIG. 1(d) shows another embodiment of the present invention, in which the reduced diameter part 10
This is an example in which c is a two-tiered structure of 10 cm and 10 c%. Further, FIG. 1(e) shows still another embodiment of the present invention,
This is an example in which the tip portion 10e of the vibrator horn 10 is cut to form a curvature R continuous to the inclined surface portion and the reduced diameter portion.

The operation of the ultrasonic atomizer of the present invention having the above configuration will be described below.

The alcohol fuel passes through the circumferential groove 5c1, the passage 9a1, the inclined passage 9b1, and the opening 9c, respectively, and reaches the atomization surface 4. At this time, the fuel is supplied to the entire circumference of the opening 9c and the inclined surface portion 10b through the entire circumference of the circumferential groove 5c, so that in the process, the fuel is made to have a roughly uniform film thickness. Then, it reaches the inclined surface portion 10b. The fuel that has reached the inclined surface portion 10b is atomized by the ultrasonic vibrations from the ultrasonic vibration generator 2, and the fuel that cannot be atomized here smoothly flows to the reduced diameter portion 10c where the entire amount is It will be atomized and sprayed at a spray angle α.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made.

〔Effect of the invention〕

As described above, according to the present invention, by improving the shape of the tip of the vibrator of the ultrasonic atomizer, it is possible to make the spray angle appropriate regardless of the amount of supplied alcohol, and the turndown ratio can be improved. A large, uniform all-round spray can be obtained, and the startability of alcohol engines is improved. Furthermore, fuel can be supplied into the cylinder without the fuel adhering to the inner wall of the intake pipe.

Furthermore, by increasing the spray flow rate, it is possible to operate the ultrasonic atomizer even during normal operation, and the mechanism is simplified because the vaporizer can be omitted.

[Brief explanation of the drawing]

FIGS. 1(a), (b), (c), (d), and (e) are sectional views of main parts showing each embodiment of the ultrasonic atomization device of the present invention, and FIG.
3 is a sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a sectional view of an alcohol engine to which the present invention is applied. 5 and 6 are cross-sectional views of conventional ultrasonic injection valves. 1... Ultrasonic atomization device, 9... Sleeve, 10...
- Vibrator horn, 10a... enlarged diameter part, 10b... inclined surface part, 10c... reduced diameter part.

Claims (2)

[Claims] (1) A vibrator horn disposed in the intake pipe for atomizing alcohol fuel; and a sleeve disposed on the outer periphery of the vibrator horn for supplying fuel over the entire circumference of the vibrator horn; An ultrasonic atomizer for an alcohol engine, characterized in that a tip of the vibrator horn is formed with an inclined surface portion and a reduced diameter portion smaller in diameter than the inclined surface portion, and an opening of a sleeve is disposed opposite to the inclined surface portion. Device. (2) The alcohol engine according to claim 1, wherein the tip of the vibrator horn is formed with an enlarged diameter portion, a reduced diameter portion smaller in diameter than the enlarged diameter portion, and smaller in diameter than the inclined surface portion. Ultrasonic atomization device.