JPH0332762A - Ultrasonic atomizing device - Google Patents

Abstract

PURPOSE:To prevent fuel from dropping out of the ultrasonic atomizing device and to improve the combustion performance of engine by making the air passage to have negative pressure when the fuel from the fuel supply passage is stopped. CONSTITUTION:An inner cylinder 2 is disposed around the outside of a vibrator main body 1, and an outer cylinder 3 is press-fitted around the outer periphery of top end of the inner cylinder 2. The fuel supply passage 6 is formed between the inner cylinder 2 and the outer cylinder 3, and the air passage 10 communicating with the outer periphery of the vibrator main body 1 is formed on the inner cylinder. The air passage 10 is made to have negative pressure when the fuel sent from the fuel supply passage 6 is stopped. As a result, the fuel is prevented from dropping out of the ultrasonic atomizing device, and the combustion performance of engine is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic atomizer used in an internal combustion engine.

[Conventional technology]

In internal combustion engines such as gasoline engines and diesel engines, in order to obtain favorable engine performance,
There is a need to atomize liquid fuel injected into an intake pipe into extremely small droplet sizes, mix with air, and supply the mixture to the combustion chamber of an engine. BACKGROUND ART Conventionally, as such a device for atomizing liquid fuel into extremely small droplet diameters, an ultrasonic atomization device that atomizes supplied liquid fuel using ultrasonic waves is known. In particular, when liquid fuel is required to be atomized over a wide flow rate range (high turndown), such as in a gasoline engine, a solenoid valve is used as the liquid fuel supply means. A method is adopted in which liquid fuel is directly supplied to the atomization surface of a sonic atomization device.

FIG. 3 shows an example in which a conventional ultrasonic atomizer is applied to an engine. In the figure, 11 is a cylinder, 12 is a piston, 13 is an intake valve, 14 is an exhaust valve, 15 is an intake pipe, 18
indicates an exhaust pipe, and the above-mentioned ultrasonic atomizer 17 and a solenoid valve 18 as a fuel injection valve are attached to the intake pipe 15. The vibrator horn 19 is arranged facing the intake valve 13.

FIG. 4 shows an ultrasonic atomizing device that supplies liquid to the entire circumference of the atomizing surface, and is composed of an outer cylinder 102, an inner cylinder 101, a IIIHII vibrator horn 103, and a vibrator horn 7103 that generates ultrasonic vibrations (not shown). Ultrasonic vibrations are applied by the generating means.

A circumferential groove 104 is formed on the outer circumference of the inner cylinder 101 over the entire circumference, and a circumferential groove 104 is formed on the outer circumference of the inner cylinder 101.
2 and the inner cylinder 101 is a fuel supply sleeve 1
07, a nozzle portion 106 is formed over the entire circumference of the vibrator horn 103, and a fuel supply hole 105 is formed.
The fuel supplied from the oscillator horn 103 is supplied from the nozzle part 106 to the atomizing surface at the tip of the vibrator horn 103 and atomized.

[Problem to be solved by the invention]

By the way, in the ultrasonic atomization H position, the fuel supplied from the fuel injection valve 18 is intermittently controlled to be injected in synchronization with the opening and closing of the intake valve 13 of the engine. However, when the fuel injection valve 18 is closed, the fuel remaining in the fuel supply sleeve 107 accumulates between the nozzle part 106 and the vibrator horn 103 due to surface tension, and drips into the intake pipe 15. However, this has had the problem of adversely affecting engine combustion performance such as air-fuel ratio and responsiveness.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide an ultrasonic atomizer that can prevent fuel from dripping from the ultrasonic atomizer and further improve the combustion performance of an engine. shall be.

[Means to solve the problem]

For this purpose, the ultrasonic atomization device of the present invention consists of an inner cylinder 2 disposed outside the vibrator body 1 and an outer cylinder 3 press-fitted into the outer periphery of the tip of the inner cylinder 2. A fuel supply passage 6 is formed between the cylinder 3 and the inner cylinder 2, and an air passage 10 communicating with the outer periphery of the vibrator body is formed in the inner cylinder 2. When fuel is cut off from the fuel supply passage 6, the air passage 10 is set to negative pressure.

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

[Effect]

In the present invention, for example, as shown in FIG. 1, the fuel supplied from the fuel injection valve passes through the fuel supply passage 6 and is sprayed from the nozzle part 8 to the vibrator hose 7, so that the fuel is atomized. Ru. When the fuel supply from the fuel injection valve 18 is cut off,
Since air is sucked from the air passage 10, the fuel supply passage 8
Even if residual fuel stays between the nozzle part 8 and the vibrator horn 7 due to surface tension, it is sucked by the air from the air passage 10 and is prevented from dripping into the intake pipe 15. I can do it.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing an embodiment of the ultrasonic atomization device of the present invention,
FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1.

In the figure, the ultrasonic atomization device consists of an inner cylinder 2 disposed outside a vibrator body 1, and an outer cylinder 3 press-fitted into the outer periphery of the tip of the inner cylinder 2.
By forming a circumferential groove 4 over the entire circumference of the inner cylinder 2 and forming an annular fuel supply passage 6 between the inner cylinder 2 and the outer cylinder 3, a nozzle portion is formed over the entire circumference of the vibrator horn 7. 8 is formed.

Further, a fuel supply hole 9 is formed in the outer cylinder 3 and communicates with the circumferential groove 4, and the fuel supply hole 9 is connected to a fuel injection valve 18 shown in FIG. Furthermore, an air passage 10 is formed in the inner cylinder 2 and communicates with the outer periphery of the vibrator body 1. The air passage 10 is connected to a negative pressure section of an intake pipe 15 via a valve (not shown),
It is configured such that air is sucked from the air passage 10 when fuel supply from the fuel injection valve is cut off.

To explain the operation of the present invention having the above configuration, the fuel supplied from the fuel injection valve 18 (FIG. 3) passes through the fuel supply path 6 and is sprayed from the nozzle part 8 to the vibrator Hoyang 7, and the fuel is atomized. be done. When the fuel supply from the fuel injection valve 18 is cut off, air is sucked from the air passage 10, so that the fuel remaining in the fuel supply passage 6 is separated between the nozzle part 8 and the vibrator horn 7 due to surface tension. Even if the liquid stagnates in the air, the air from the air passage 10 sucks the liquid and prevents the liquid from dripping into the intake pipe 15.

Note that it is even more effective if the present invention is applied to an MPI system in which a fuel injection valve is arranged in each cylinder of a multi-cylinder engine. In this case, the air passages 10 of the ultrasonic atomizers disposed in each cylinder are connected to other intake pipe negative pressure sections. Due to the difference in the timing of the intake valves in each cylinder, the air passages become under negative pressure one after another, so it is possible to prevent fuel from dripping in each cylinder.

〔Effect of the invention〕

As explained above, according to the ultrasonic atomization device of the present invention,
Since air is sucked from the air passage when fuel supply from the fuel injection valve is cut off, it is possible to prevent fuel from dripping from the ultrasonic atomizer and further improve the combustion performance of the engine.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the ultrasonic atomization device of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a sectional view showing a conventional ultrasonic atomization device. FIG. 4 is a cross-sectional view showing an example of application to an engine, and FIG. 4 is a schematic cross-sectional view showing an example of a conventional ultrasonic atomizer. l... Vibrator body, 2... Inner cylinder, 3...
...Outer cylinder, 8...Fuel supply path, 7
... Vibrator horn, 8... Nozzle part, 10...
air passage.

Claims (1)

[Claims] (1) Consisting of an inner cylinder disposed outside the vibrator body and an outer cylinder press-fitted onto the outer periphery of the tip of the inner cylinder, and a fuel supply path is formed between the inner cylinder and the outer cylinder. The ultrasonic atomizer is characterized in that an air passage communicating with the outer periphery of the vibrator body is formed in the inner cylinder, and the air passage is made to have a negative pressure when fuel is cut off from the fuel supply passage.