JPH10266897A - Vaporizer - Google Patents

Abstract

(57) [Problem] To provide a vaporizer whose durability is not inferior even if the diameter of a power jet nozzle is reduced. In a carburetor, a nozzle is provided in a venturi passage, and a fuel jet is provided from the nozzle to supply or shut off fuel into the venturi passage according to the engine speed. The nozzle 2 is formed in a linear shape crossing the venturi passage 15.
The two ends are supported at both ends by walls 15a of the venturi passage 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporizer, and more particularly to a vaporizer provided with a special power jet.

[0002]

2. Description of the Related Art Some engines used in vehicles have a carburetor in the middle of an intake passage. The vaporizer is
The fuel is atomized and mixed with air to be easily vaporized and supplied to the engine, and an appropriate air-fuel mixture is produced according to the operating (temperature) state of the engine. The structure of the vaporizer can be roughly classified into a float system, a start system, a slow system, and a main system.

[0003] Among them, the float system is for keeping the oil level of the fuel sent from the fuel tank to the float chamber of the float chamber at a constant height. Also, the starting system is for facilitating the cold start of the engine. Further, the slow system is for supplying necessary fuel during low-speed rotation of the engine, and the main system is for supplying necessary fuel during normal traveling and high-speed traveling.

[0004] Incidentally, in order to obtain higher output and higher torque, a carburetor is provided with a power jet in addition to the main system, so that fuel flows out into the venturi passage to form a rich mixture. (For example, see JP-A 1-27
7669).

As a general example of the structure, as shown in FIG. 7, a nozzle 3 extending from a power jet 2 provided in a vaporizer 1 is projected from a wall surface of a venturi passage 4 toward a center of the passage 4. There are things. Power jet 2
Is provided with a solenoid valve 6 for opening and closing the jet 5 and is configured to supply or shut off fuel to the venturi passage 4 in accordance with the engine speed.

[0006]

However, since the power jet nozzle described above is a cantilever support, there is a possibility that the nozzle cannot sufficiently withstand high-speed air flowing in the venturi passage. If the diameter of the nozzle is increased, the durability will be improved.
On the other hand, since the air resistance increases and hinders the flow of air in the Venturi passage, adversely affecting the engine output and response, there is a limit to the thickness of the nozzle diameter.

The present invention has been made in view of the above-described circumstances, and has as its object to provide a carburetor which is not inferior in durability even if the diameter of a power jet nozzle is reduced.

Another object of the present invention is to provide a carburetor in which the air resistance of the nozzle is reduced.

[0009]

The vaporizer according to the present invention comprises:
In order to solve the above-mentioned problem, as described in claim 1, a nozzle is provided in a Venturi passage, and a power jet that supplies or shuts off fuel from the nozzle into the Venturi passage according to the engine speed is provided. In the carburetor provided, the nozzle is formed in a linear shape crossing the Venturi passage, and both ends of the nozzle are supported at both ends by walls of the Venturi passage.

In order to solve the above-mentioned problem, the diameter of the tip of the nozzle is reduced to form a stepped shape.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a rear view of a carburetor used for a small vehicle such as a motorcycle. As shown in FIG. 1, a throttle body 12, which is a main body of the vaporizer 11, is formed by die-casting a light metal material such as aluminum. A float chamber 13 for storing fuel is provided below the throttle body 12, and a float chamber 14 is formed therein. Further, a venturi passage 15 is formed in the center of the throttle body 12.

The carburetor 11 has a power jet 16 for obtaining higher output and higher torque. The power jet 16 is mainly provided in the float chamber 14 and the venturi passage 15.
A fuel passage 17 communicating with the inside, a jet 18 provided in the middle of the fuel passage 17, and a solenoid valve 1 for opening and closing the jet 18 in accordance with the engine speed.
9 and a nozzle 20 arranged in the venturi passage 15.

The nozzle 20 has one end attached to the outlet 17a of the fuel passage 17 and the other end fitted into a recess 21 formed in a venturi passage wall 15a facing the outlet 17a of the fuel passage 17, and It is configured in a straight line crossing the passage 15. The nozzle 20 has a fuel injection port 22 approximately in the middle.

FIG. 2 is an enlarged sectional view showing the first embodiment of the nozzle 20. The nozzle 20 shown in FIG. 2 is obtained by extending the tip of the conventional nozzle 3 without changing the diameter of the nozzle 3 (see the conventional example of FIG. 7).

FIG. 3 is an enlarged sectional view showing a second embodiment of the nozzle. The nozzle 30 shown in FIG. 3 has a stepped shape in which the diameter of the extended tip of the nozzle 20 shown in FIG. 2 is reduced.

FIG. 4 is an enlarged sectional view showing a third embodiment of the nozzle. The nozzle 40 shown in FIG. 4 is one in which both ends are pressed into the venturi passage wall 15a using a pipe material and sealed.

Next, the operation of the present embodiment will be described.

FIG. 5 is a control characteristic diagram of the power jet 16. As shown in FIG. 5, when the engine speed N is less than the maximum horsepower speed N _ON , the power jet 16 is opened by operating the solenoid valve 19 (power jet O).
N), and when the engine speed N reaches the maximum horsepower speed N _ON , the solenoid valve 19 is turned on to maintain a closed state (power jet OFF). The solenoid valve 19 is turned on a predetermined number of times when the main switch is turned on when the engine is not rotating, so that the operation of the solenoid valve 19 can be confirmed.

When the engine is started and its rotational speed N is N _ON
Until the power jet 16 is turned on, the fuel is discharged from the fuel outlet 22 of the nozzle 20 as the air flowing through the venturi passage 15 increases in speed.
5, and the output and torque are improved.

On the other hand, when the engine speed N reaches N _ON , the power jet 16 is turned off, the supply of fuel into the venturi passage 15 is cut off, and a decrease in output and torque due to rich mixture is prevented. You.

As shown in the performance curve of FIG. 6, these operations are performed when the engine output P and the fuel flow rate Q do not include the power jet 16 indicated by the broken line when the engine speed N is at the maximum horsepower speed N _ON . , The engine output P is improved, and the fuel flow rate Q is reduced.

The nozzle 20 of the power jet 16, which has been conventionally cantilevered, is supported at both ends so that the nozzle 20 can sufficiently withstand high-speed air flowing through the venturi passage 15.

In addition, since the nozzle 20 is supported at both ends, a stepped shape in which the diameter of the tip of the nozzle 30 is reduced can be used, and the air resistance of the nozzle 30 in the venturi passage 15 is reduced, so that the venturi is reduced. The flow of air in the passage 15 is not obstructed. Therefore, there is no adverse effect on engine output and response.

Further, by forming the nozzle 40 using a pipe material, the cost can be reduced.

[0026]

As described above, according to the carburetor according to the present invention, a nozzle is provided in the Venturi passage, and fuel is supplied from the nozzle to the Venturi passage in accordance with the engine speed or shut off. In a vaporizer equipped with a power jet, the nozzle is configured to have a linear shape crossing the Venturi passage, and both ends of the nozzle are configured to be supported at both ends by walls of the Venturi passage. The diameter can be reduced.

In addition, since the diameter of the tip of the nozzle is reduced to form a step, the air resistance is reduced.

[Brief description of the drawings]

FIG. 1 is a rear view showing one embodiment of a vaporizer according to the present invention.

FIG. 2 is an enlarged sectional view showing a first embodiment of the nozzle.

FIG. 3 is an enlarged sectional view showing a second embodiment of the nozzle.

FIG. 4 is an enlarged sectional view showing a third embodiment of a nozzle.

FIG. 5 is a control characteristic diagram of a power jet.

FIG. 6 is a performance curve diagram of a power jet.

FIG. 7 is a rear view of a conventional vaporizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Vaporizer 12 Throttle body 15 Venturi passage 16 Power jet 17 Fuel passage 18 Jet 19 Solenoid valve 20, 30, 40 Nozzle 21 Depression formed in Venturi passage wall

Claims (2)

[Claims] 1. A carburetor provided with a nozzle in a Venturi passage and having a power jet for supplying and shutting off fuel from the nozzle to the Venturi passage according to the engine speed. A carburetor characterized in that it is formed in a linear shape crossing the nozzle 15 and is supported at both ends by supporting both ends of the nozzle 20 by walls 15 a of the venturi passage 15. 2. The vaporizer according to claim 1, wherein the diameter of the tip of the nozzle 20 is reduced to form a stepped shape.