JPH0717808Y2 - Vaporizer - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a carburetor installed in an intake system of an engine, and more specifically, to a fuel vapor bubble generated in a main fuel system from a main air bleed at the time of starting the engine and the carburetor at high temperature and idling. Reliably discharge and prevent fuel from overflowing from the main nozzle,
The present invention relates to a carburetor capable of improving startability at high temperature and idle stability after high temperature start.

[Prior art]

Generally, a carburetor generally includes a main fuel system and a slow fuel system. As shown in FIG. 2, the fuel 2 in the float chamber 1 of the carburetor C is a main jet 3 provided at the bottom of the float chamber 1. Through the passage 4 to the main well 5 of the main fuel system and the slow jet 6 of the slow fuel system. Here, when the engine is loaded, the fuel 2 in the main well portion 5, which is the main fuel system, flows into the intake passage of the carburetor C.
The air flowing in from 7a through the main air bleed 7 is mixed with the emulsion tube 8 and ejected from the main nozzle 9 into the venturi 10. Also, when starting the engine or idling,
Emulsion hole through the fuel 2 measured by the slow jet 6 of the slow fuel system and the economizer bleed 11.
The air that enters from 12 mixes with the air that enters from the slow air bleed 13, and the mixture is atomized and ejected from the idle hole 15 and the bypass hole 16 through the slow passage 14. ing. Here, in the vaporizer C, various ideas have been made for an emulsion tube for improving the mixing of the fuel 2 and the air. For example, as shown in Japanese Utility Model Laid-Open No. 56-17342, a small hole is formed in the lower part. There is one in which an air bleed is integrally provided in the vicinity of the upper open portion of the drilled emulsion tube to mix air and fuel.

[Problems to be solved by the device]

By the way, in the conventional carburetor C, the engine and the carburetor are in a high temperature state at the time of starting the engine or idling, and the fuel in the main fuel passage 4 and the main well 5 is vaporized. When bubbles of fuel vapor are generated as a result, the bubbles rise in the emulsion tube 8 together with the fuel. When the buoyancy of the bubbles in the emulsion tube 8 becomes equal to the weight of the fuel on the upper side of the bubbles, the rising of the bubbles stops and vapor lock is caused, and the fuel flows into the main nozzle 9 together with the bubbles by the pumping action of the bubbles. Come on. Therefore, fuel is intermittently supplied from the main fuel system during the engine operation by the slow fuel system, and there is a problem that the idle stability is lowered and the startability is deteriorated even at the time of starting. The present invention has been made in view of the above circumstances, and reliably discharges the bubbles of fuel vapor generated in the main fuel system from the main air bleed at the time of starting the engine and the carburetor in a high temperature state and idling. It is an object of the present invention to provide a carburetor capable of preventing fuel from overflowing from the main nozzle and improving startability at high temperature and idle stability after high temperature start.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a vaporizer having a main fuel system including a main well portion into which an emulsion tube is inserted in a state where a separator chamber is formed between an upper end of the emulsion tube and a main air bleed. At the upper end of the separator, a cylindrical gas-liquid separator that projects a predetermined amount into the separator chamber while maintaining a predetermined distance from the peripheral wall of the separator chamber is connected.

[Action]

In the carburetor according to the present invention which adopts such means, the engine and the carburetor are in a high temperature state at the time of starting the engine or idling, and the fuel in the passage of the main fuel system and the main well part is boiled and vaporized. When bubbles of fuel vapor are generated, these bubbles enter the emulsion tube together with the fuel and rise in the emulsion tube and in the gas-liquid separator that is connected to the emulsion tube, and pops at the upper end of the gas-liquid separator facing the separator chamber. Gas-liquid separation. Then, the fuel component separated from the gas-liquid flows along the outer periphery of the gas-liquid separator and collects on the upper end surface of the emulsion tube forming the bottom of the separator chamber, and only the fuel vapor is diffused from the main air bleed into the intake passage of the carburetor. . In addition, the fuel accumulated on the upper end surface of the emulsion tube is also in a high temperature state in the carburetor, and eventually evaporates and is diffused from the main air bleed into the intake passage of the carburetor.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an enlarged sectional view showing a main part of a carburetor according to an embodiment. In the figure, the same parts as those of the conventional example are designated by the same reference numerals and described. First, in the main well portion 5 of the vaporizer C, a small hole is formed in the lower portion.
An emulsion tube 8 having a large number of holes 5a is fitted to the inner wall of the main well portion 5 with a predetermined gap.
A main air bleed 7 is installed above the emulsion tube 8, and a separator chamber 17 is formed between the main air bleed 7 and the upper end of the emulsion tube 8. Here, at the upper end of the emulsion tube 8, a cylindrical gas-liquid separator 18 is fitted and continuously connected to the peripheral wall of the separator chamber 17 with a predetermined distance and protruding into the separator chamber 17 by a predetermined amount. Has been done. Next, the operation of the carburetor C of one embodiment configured as described above will be described. When the engine and the carburetor are in a high temperature state at the time of starting the engine or idling and the fuel in the passage 4 of the main fuel system and the fuel in the main well portion 5 is boiled and vaporized to generate bubbles of fuel vapor, these bubbles are generated. Enter the emulgin tube 8 together with the fuel and
The inside of the gas-liquid separator 18 connected to the inside and the inside of the gas-liquid separator 18 are lifted, and the upper end of the gas-liquid separator 18 facing the inside of the separator chamber 17 bounces to separate the gas-liquid. The gas and liquid are separated, and the minute amount of fuel is separated into gas and liquid separator 18
Along the outer periphery of the fuel cell and accumulated on the upper end surface of the emulsion tube 8 forming the bottom of the separator chamber 17, and only the fuel vapor is diffused from the main air bleed 7 into the intake passage 7a of the carburetor C. Further, the minute fuel component accumulated on the upper end surface of the emulsion tube 8 is also vaporized and vaporized in the high temperature state of the vaporizer C, and is eventually diffused from the main air bleed 7 into the intake passage 7a of the vaporizer C. Therefore, the bubbles of the fuel vapor that have entered the emulsion tube 8 are sequentially diffused from the main air bleed 7 to the intake passage 7a of the carburetor C, and the bubbles are accumulated in the emulsion tube 8 as in the conventional case, and vapor lock is performed. Therefore, the situation where the fuel flows into the main nozzle 9 together with the bubbles due to the pumping action of the bubbles and overflows from the main nozzles is avoided, and the idle stability decreases and the startability deteriorates. The problem of is solved.

[Effect of device]

As described above, in the present invention, when the engine is started or idling, the engine and the carburetor are in a high temperature state, the fuel in the passage of the main fuel system and the fuel in the main well are boiled and vaporized to generate bubbles of fuel vapor. Then, the bubbles enter the emulsion tube together with the fuel, rise in the emulsion tube and in the gas-liquid separator connected to the emulsion tube, and bounce at the upper end of the gas-liquid separator facing the separator chamber to be separated into gas and liquid. Then, the separated fuel and gas components travel along the outer periphery of the gas-liquid separator and accumulate on the upper end surface of the emulsion tube that forms the bottom of the separator chamber, and only the fuel vapor is diffused from the main air bleed into the intake passage of the carburetor. . In addition, the fuel accumulated on the upper end surface of the emulsion tube is also in a high temperature state in the carburetor, and eventually evaporates and is diffused from the main air bleed into the intake passage of the carburetor. Therefore, according to the present invention, the bubbles of the fuel vapor that have entered the emulsion tube are reliably diffused and discharged from the main air bleed to the intake passage of the carburetor sequentially.
It is possible to reliably avoid the situation where bubbles accumulate in the emulsion tube and cause vapor lock as in the past, and the fuel pump overflows with the bubbles from the main nozzle due to the pumping action of the bubbles. And idle stability after hot start can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing the structure of the main part of a vaporizer according to the present invention, and FIG. 2 is a sectional view showing the structure of a conventional vaporizer. 3 ... Main jet, 4 ... Passage, 5 ... Main well part, 7 ... Main air bleed, 8 ... Emulsion tube, 9 ... Main nozzle, 17 ... Separator chamber,
18: Gas-liquid separator.

Claims (1)

[Scope of utility model registration request] 1. A carburetor having a main well system in a main fuel system, wherein a main well portion is inserted in a state where a separator chamber is formed between an upper end of the emulsion tube and a main air bleed. A vaporizer characterized in that a cylindrical gas-liquid separator is provided continuously in a predetermined distance from the peripheral wall of the separator chamber so as to project into the separator chamber by a predetermined amount.