JPS634017B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor in which the shape of the entrance of an intake passage formed in a carburetor body can be freely set according to the characteristics of an engine.

Changing the shape of the entrance to the intake tract will change the pulsation effect and inertial effect of the engine's intake system, so the shape of the entrance to the intake tract must match the characteristics of the engine. Therefore, in the past, multiple types of carburetor bodies were prepared with different intake duct entrance shapes to accommodate various engines with different characteristics. It has become an obstacle.

The present invention has been proposed in view of the above, and has an extremely simple structure that enables the same carburetor body to be commonly used in various engines with different intake duct entrance shapes. The main purpose is to provide equipment.

In order to achieve the above object, the present invention provides an annular recess at the upstream end of the intake path of the carburetor main body,
An air horn whose inner circumferential surface forms the entrance of the intake passage is removably fitted into this annular recess, and the inner circumferential surface of the horn is formed into a ruffled shape with an upstream end having a diameter larger than that of the downstream end. An annular groove defining an annular passage between the air horn and the inner surface of the annular recess, and a communication hole communicating the annular groove with the inlet are provided at the downstream end of the air horn, and the vaporizer main body is provided in the annular groove. It is characterized by opening the entrance of an auxiliary air passage such as a bleed air passage inside the air passage.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a carburetor main body 1 has a horizontal intake path 2, and a float chamber 3 is provided in the lower part thereof. The intake passage 2 includes a main fuel nozzle 4,
A bypass port 5 and an idle port 6 are sequentially provided downstream from the central bench lily portion 2a, that is, toward the engine side, and a throttle valve 7 is provided adjacent to the bypass port 5. The fuel in the float chamber 3 is transferred to the main fuel nozzle 4 from the main fuel jet 8.
is metered and emulsionized with bleed air in the main emulsion pipe 9, and then supplied.
Furthermore, the fuel in the float chamber 3 is transferred to the bypass port 5 and the idle port 6 from the main fuel jet 8.
The fuel is metered by a low-speed fuel jet 10, emulsified with bleed air in a low-speed emulsion pipe 11, and then supplied. Bleed air path 12 and low speed bleed air path 1
3 is provided by perforating the side wall of the carburetor body 1.

An annular recess 14 is provided at the upstream end of the intake passage 2, and an air horn 15 whose inner peripheral surface forms the entrance 2b of the intake passage 2 is inserted into the seal member 1.
6 so that they can be inserted and removed. The inner circumferential surface of the air horn 15 is formed into a tangled shape with an upstream end having a larger diameter than a downstream end. A large number of air horns 15 with different shapes of inlet 2b are prepared, and one suitable for the characteristics of the engine is selected from among these and installed in the annular recess 14.

An annular groove 18 defining an annular passage 17 between the air horn 15 and the inner surface of the recess 14 is formed on the downstream end surface of the air horn 15.
This groove 18 communicates with the inlet 2b via a communication hole 19 cut out in the inner circumferential wall thereof.
Inlets of a main bleed air passage 12 and a low-speed bleed air passage 13 are opened in the annular passage 17, and a main air jet 20 and a low-speed air jet 21 are fitted into these inlets. Therefore, air horn 1
5 enters the annular passage 17 from the communication hole 19, is metered by the main air jet 20 or the low speed air jet 21, and passes through the main bleed air path 12 or the low speed bleed air path 13,
Main emulsion tube 9 or slow emulsion tube 1
1.

In this way, when the air jets 20 and 21 are communicated with the intake passage 1 through the annular passage 17 and the communication hole 19, the intake pulsation pressure of the engine is attenuated by the annular passage 17, so that it hardly affects the air jets 20 and 21. In addition, even when the engine backfires, soot flowing backward through the intake passage 1 will not enter the air jets 20 and 21, preventing them from clogging, thus ensuring a predetermined amount of bleed air at all times. can do.

Incidentally, the annular passage 17 can also be opened at the entrance of the air passage of the float chamber 3.

A case 23 of an air cleaner 22 that filters the intake air of the intake passage 2 is connected to the upstream end of the carburetor body 1, and this case 23 comes into contact with the outer end of the air horn 15 to prevent the air horn 15 from coming off. .

As described above, according to the present invention, an annular recess is provided at the upstream end of the intake path of the carburetor main body, and an air horn whose inner peripheral surface forms the entrance of the intake path is removably inserted into the annular recess. At the same time, the inner circumferential surface of the horn is formed into a round shape with the upstream end having a larger diameter than the downstream end. The shape of the entrance can be easily adapted to the characteristics of various engines, and the same carburetor body can therefore be used for all types of engines, which greatly contributes to improving the mass production of carburetors. be able to.

Further, an annular groove defining an annular passage between the air horn and the inner surface of the annular recess, and a communication hole communicating the annular groove with the inlet are provided at the downstream end of the air horn. Since the inlet of the auxiliary air passage such as the bleed air passage in the main body is opened, the damping effect of the annular passage can prevent the influence of the intake pulsation pressure of the engine and the backfire on the auxiliary air passage. This annular passage is defined between the annular groove provided at the downstream end of the air horn, that is, the end with the smaller inner diameter, and the inner surface of the annular recess, so that the air horn can be connected to the inside of the annular recess. While effectively utilizing the annular dead space formed between the annular passage and the surrounding surface, it is possible to ensure a sufficiently large effective volume of the annular passage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a carburetor showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. 1... Carburetor main body, 2... Intake path, 2b... Intake path entrance, 12... Main bleed air path, 13...
Low speed bleed air passage, 15...Air horn, 17
... annular passage, 18 ... annular groove, 19 ... communication hole.

Claims (1)

[Claims] 1. An annular recess is provided at the upstream end of the intake tract of the carburetor body, and an air horn whose inner peripheral surface forms the entrance of the intake tract is removably fitted into the annular recess, and the inner periphery of the horn The surface is formed into a lap shape with the upstream end having a larger diameter than the downstream end, and the downstream end of the air horn includes an annular groove defining an annular passage between the inner surface of the annular recess and the annular groove. The carburetor is provided with a communication hole communicating with the inlet, and the annular groove is provided with an inlet of an auxiliary air passage such as a bleed air passage in the carburetor main body.