JPS6238860A - Outer vent device of carburetor in saddle type vehicle - Google Patents

Abstract

PURPOSE:To reduce the variation of air-fuel ratio by softening the dynamic pressure supplied from an atmosphere opened pipe by installing an expansion case communicating to a communication pipe connected to the outer vent port of a carburetor and connecting the tail edge of the atmosphere opened pipe to the outlet of the expansion case. CONSTITUTION:A plurality of communication pipes 4 are connected to the outer vent ports 3a of a plurality of carburetors 3, and a cylindrical expansion case 5 is connected to each communication pipe 4. A triangular opened port 5a is formed at the upper edge of the expansion case 5, and the edge part of each communication pipe 4 is inserted into the expansion case 5 from the opened port 5a. Further, an outlet 5b projecting downwardly is formed at the lower edge of the expansion case 5, and the tail edge of an atmosphere opened pipe 6 whose top edge is opened to the atmosphere is connected to the outlet 5b. Therefore, even if a dynamic pressure acts into the atmosphere opened pipe 6 by the influence of the traveling wind, said dynamic pressure can be softened in the expansion case 5, and the variation of the internal pressure due to the dynamic pressure acting into each carburetor 3 through each communication pipe 4 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an outer vent device for a carburetor in a saddle type vehicle such as a motorcycle or a tricycle.

(Prior Art) Conventionally, as a device of this kind, it is known that the outer vent of the carburetor is opened to the atmosphere through a communication pipe connected to the outer vent hole of the carburetor to suppress changes in the internal pressure of the float chamber of the carburetor.
In this case, evaporated fuel from the outer vent may condense in the communication pipe and drip from the open end of the communication pipe, so the open end is positioned below the vehicle body to prevent this from adhering to the vehicle body.

(Problem to be Solved by the Invention) However, if the open end of the communication pipe is located below the vehicle body, positive pressure or negative pressure, that is, Dynamic pressure acts, and the internal pressure of the float chamber changes due to this dynamic pressure, making the air-fuel ratio liable to fluctuate, making positioning of the open end extremely troublesome.

In addition, in a multiple vaporizer, each out vent of the plurality of vaporizers is opened to the atmosphere through a separate communication pipe, so the dynamic pressure acting on the float chamber differs from vaporizer to vaporizer.
There is a problem that the air-fuel ratio varies between cylinders.

(Means for Solving the Problems) The first invention of the present application is a device that suppresses the action of dynamic pressure on the float chamber, thereby stabilizing the air-fuel ratio and making it easier to set the position of the end open to the atmosphere. The purpose is to provide a vaporizer with an expansion case connected to a communication pipe connected to the outer vent port of the vaporizer, and one end of which is open to the atmosphere and the other end of the atmosphere open pipe is connected to the outlet of the expansion case. I took it as a thing.

The second invention of the present application solves the above-mentioned problems in the multiple carburetor, and uses an expansion case similar to the first invention, which is connected to each outer vent port of a plurality of vaporizers that constitute the multiple carburetor. Each of the communicating pipes was made to communicate in common.

(Function) According to the first invention, the dynamic pressure from the atmosphere open pipe is relaxed within the expansion case, and the internal pressure change in the float chamber of the carburetor due to the action of the dynamic pressure through the communication pipe is slight. , fluctuations in the air-fuel ratio are suppressed.

Further, according to the second invention, the outer vents 1-
The mouth will be communicated with the beans within the expansion case,
In addition to the relaxation of the dynamic pressure described above, the internal pressures of the float chambers of these carburetors can be made uniform, and variations in air-fuel ratio between cylinders can be prevented.

(Example) Embodiments of the present invention will be described based on the drawings.

Referring to FIG. 1, (1) shows the body of a two-wheeled motor vehicle;
In the middle of the vehicle body (1), there are three cylinders (2
a) is equipped with a three-cylinder engine (2), and
In front of the upper cylinder (2a), as shown in Fig.
A triple carburetor consisting of three carburetors (3) (3) (3) combined in a row is installed, and air-fuel mixture is supplied from each carburetor (3) to each cylinder (2a). I made it.

Then, 313 communication pipes (4) (4) (4) each connected to the outer ventro (3a) of each carburetor (3) and a substantially cylindrical expansion case (5) are provided, and the case ( 5
) has a substantially triangular opening (5a) as shown in Figure 4.
), and inserting the ends of the three communicating pipes (4) (4) (4) into the case (5) from the opening (5a),
These communication pipes (4) (4) (4) and the case (5)
The tail of the atmosphere opening pipe (6) is formed with an outlet (5b) projecting downward at the lower end of the case (5), and the tip of the outlet (5b) is opened. Connected the ends.

The case (5) has a pair of upper and lower protrusions (
5C) (5c) It shall be installed in a place where it is not exposed to the running wind, such as the rear part of the crankcase (2b) of the engine (2) as shown in Fig. 2, using the mounting bracket (1) wrapped and fixed between the parts. The tip of the open pipe ω) is connected to the vehicle body (1)
It faced between the left and right exhaust pipes (8) (8) below.

Note that the ends of each of the communication tubes (4) to be inserted into the expansion case (5) were cut diagonally.

According to the above configuration, due to the influence of the running wind, the air opening pipe (6)
Even if dynamic pressure builds up in the float chamber, this dynamic pressure is relaxed within the expansion case (5), and the float chamber is reduced by the dynamic pressure acting on the float chamber of each vaporizer (3) via each communication pipe (4). Internal pressure changes are suppressed, and the outer ventro (3) of each carburetor (3) is suppressed.
a) are communicated with each other in the expansion case (5), so that the flows 1 to 3 of the three vaporizers (3) (3) (3)
The internal pressure in the chamber is made uniform, and variations in air-fuel ratio between cylinders are also prevented.

Furthermore, in the illustrated embodiment, a small hole (5d) is formed in the expansion case (5) to open the inside of the expansion case (5), and an atmosphere opening pipe (5d) is formed in the expansion case (5).
6) is blocked by water distribution, etc., each communication pipe (4) is opened to the atmosphere through the small hole (5d), and the air can be moved in and out through the small hole (5d). The pressure relief function has been further improved.

In addition, the popular open pipe (6) is designed in consideration of dripping of condensed fuel.
It is necessary to install the expansion case so that its open end is located below the vehicle body, but there is no restriction on the installation position for the expansion case (5), and it can be installed in a place where it is not exposed to the wind while driving. For example, the action of dynamic pressure through the small hole (5d) can be prevented, and there is no adverse effect due to the formation of the small hole (5d).

The embodiment of the second invention applied when multiple carburetors are mounted on a vehicle has been described above, but as shown in FIG. The expansion case (
By providing 5), changes in the internal pressure of the float chamber due to dynamic pressure can be suppressed.

Further, the shape of the expansion case (5) is not limited to the cylindrical shape as in the above embodiment, but may be any shape such as a rectangular parallelepiped or a conical shape.

(Effects of the Invention) As described above, according to the present invention, the expansion case relieves the dynamic pressure from the atmosphere-opening pipe, suppresses changes in the internal pressure of the float chamber of the carburetor, and prevents the traveling wind from hitting the tip of the atmosphere-opening pipe. Fluctuations in the air-fuel ratio due to the effects of According to the second invention, the internal pressures of the float chambers of the plurality of carburetors constituting the multiple carburetor are equalized, and there is an effect that variations in the air-fuel ratio among the cylinders are also prevented.

[Brief explanation of drawings]

Fig. 1 is a side view of a motorcycle equipped with the device of the present invention, Fig. 2 is an enlarged side view of its main parts, Fig. 3 is a perspective view showing the relationship between the carburetor and the expansion case, and Fig. 4 is the expansion case. An enlarged perspective view of the case, FIG. 5 is a perspective view corresponding to FIG. 3 of another embodiment. (3)... Carburetor (3a)... Outer ventro (4)... Communication pipe (5)... Expansion case (5b)... Outlet (6)... Atmospheric release pipe (1! ! 2 people, □8'・ Ward O Bad faction

Claims (1)

[Claims] 1. An outer vent device for a carburetor mounted on a motorcycle or other saddle type vehicle, which includes an expansion case connected to a communication pipe connected to an outer vent port of the carburetor, and an outlet of the expansion case. An outer vent device for a carburetor in a straddle-type vehicle, characterized in that the tail end of an atmosphere release pipe whose tip is open to the atmosphere is connected to the outer vent device. 2. The outer vent device for a carburetor in a saddle-type vehicle according to claim 1, wherein the expansion case has a small hole that communicates the inside thereof with the atmosphere. 3. An outer vent device for a multiple carburetor mounted on a motorcycle or other straddle-type vehicle, in which a common extension is connected to each communication pipe connected to each outer vent port of a plurality of carburetors that make up the multiple carburetor. 1. An outer vent device for a carburetor in a straddle-type vehicle, characterized in that a case is provided, and a tail end of an atmosphere release pipe whose tip is open to the atmosphere is connected to an outlet of the expansion case. 4. The outer vent device for a carburetor in a straddle-type vehicle according to claim 3, wherein the expansion case has a small hole that communicates the inside thereof with the atmosphere.