JPS58211555A - Device for preventing percolation of carbureter - Google Patents

Abstract

PURPOSE:To effectively prevent the percolation by constituting an air suction line from an air vent pipe which communicates a float chamber with an air passage at the upstream side of Venturi and a passage which leads from the float chamber to a negative pressure port opening in the Venturi. CONSTITUTION:The carbureter exhausts a fuel in the float chamber 3 from a main nozzle 11 of a small Venturi 7 through a fuel passage 10. Further, an air passage 12 on the upstream sides of large and small Venturis 7 and 8 is communicated with the upper part of the oil level within the float chamber 3 by means of an air vent pipe 13. A negative pressure port 15 is opened at a position of the above large Venturi 8, and the negative pressure port 15 is communicated and connected to the upper part of the oil level of the float chamber 3 by means of a passage 16. An air flow line 17 through which air can flow via the float chamber 3 by idling drive and the like after starting the engine, which has particularly a large influence of percolation, is formed by the air vent pipe 13 and the passage 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is suitable for use in the carburetor of a vehicle internal combustion engine.
Relating to radiation protection equipment.

When the engine is used at low temperatures, such as during the summer, the float 1°, which stores fuel at a constant temperature of +11°, is heated by the engine, etc., and is operated at high speed (/i1).
1-1・The m paddy in the room is coming in and going out/, -me, fuel + J Noroto inside the room Jll! It! I can't wait to hear it.''
Does not cause problems such as lag. On the other hand, when idling and driving at low speeds, the time the fuel stays in the float chamber is relatively long, so it heats up and gets heated up.
Produces trout fuel vapor. During idling, fuel vapor seeps into the mixture passage, resulting in an overly rich mixture, resulting in poor operation, and when driving at low speeds, steam bubbles block the fuel passage, causing intermittent flow of fuel from the main nozzle, etc. There were problems with the bar's range, such as poor running due to the impact.

Measures to prevent conventional bar damage
By blocking radiant heat and heat transfer from the engine body to the carburetor using a heat shield plate and an insulator, and by cooling the carburetor with a cold #1 no. The method of doing this is used. However, in recent years, the shape of the ψ body has been made leaner to reduce air resistance, and due to heavy use of the ψ body, the number of parts in the engine room has become extremely large. There is little room inside, making it difficult to ensure τ ventilation, reducing the effectiveness of the above-mentioned heat shield plate, etc., and tending to cause bar occupancy.

In addition, as a treatment measure for fuel vapor actually generated [4゜For example, Utility Model Application Publication No. 55-139256jL, Utility Model Application Publication No. 55-4
Like the prior art of Publication No. 4003, Machine In Stop-v1
, a float chamber is connected to a fuel vapor adsorption device such as a canister. However, with this method, it is not possible to deal with the generation of fuel vapor after engine operation.

In view of these circumstances, the present invention has been developed to stop the engine (1)〇-
By passing air through the exhaust chamber, the fuel vapor that has already gone into R1 can be quickly removed. It should be possible to directly suppress steam.

Provides 11 shells of vaporizer pearls.

The aim is to

This 1” target! In the device according to the present invention, a vent pipe is used to cover the bench and communicate with an air passage on the downstream side. From 1 to 4, the passage communicating with the negative pressure port opened at the same time allows air to flow through the air intake system path through the float chamber into the float chamber, and immediately after the engine starts, The fuel vapor accumulated in the F-pump is discharged, and then the fuel vaporization is promoted to lower its temperature.
It is characterized by the ability to generate fuel vapor.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. A valve 5 is provided which operates in conjunction with the fuel pump 6, so that the fuel pumped by the fuel pump 6 is always stored at a constant level in the flow 1-v3 by opening and closing the valve 5.
Code 1 is small bench 1, 8 is large bench 1], 9 is s
There is a tutle valve, the fuel in the float chamber 3 is connected to the fuel passage 1.
It is sucked out from the main nozzle 11 of the small vent f1 through the small vent f1. In history, the air passage 12 on the E flow side of the venturi 7.8 communicates with the oil level 1 of the no. ”,
It is designed to prevent over-enrichment of the air-fuel mixture when refueling the Menleaf 14.

In such a configuration, the air passage 12 has a crease 14 [close to the abend pipe 13 which is almost in the atmosphere, but the venturi 7.8 on the downstream side is exposed to the intake air port during engine operation. The flow of air can cause negative pressure on the bench, although to some extent.

Also, large bench lily 8's bench" I If 4. Although it is smaller than that of the L small vent IJ-1, the flow i-'\! due to the differential pressure with the 1-abend pipe 13! This is enough to flow 3 air. In consideration of this, a negative pressure port 15 is opened in the large bench 8, and this negative pressure [115 is caused by the passage 16] II.
The vent pipe 13 and the passage 16 are connected to the upper part of the oil level in the l chamber 3, and the vent pipe 13 and the passage 16 allow the idling operation after starting the engine to be carried out, especially due to the influence of the valve cylinder.
-1-d 3 iY (An air circulation path 11 through which air flows is constructed.

Because of this configuration, eye 1 after machine start IJ
~ When driving at low speeds and at low speeds, 1)'t < 7 topai l° 1: Buttock popularity 11 (although there are 341., people l\
) f-1su8 @1rll! The negative pressure on the bench 1 is increased by 1 due to the intake air flow, and this differential pressure causes air to flow from the air vent pipe 13 through the foot chamber 3 to the C passage 16.

Due to this air flow in the chamber 3, any fuel IP4 vapor emitted during the bell is immediately expelled. Well, float? 3 When the internal atmosphere becomes unsaturated, when the humidity is high, the vaporization shown in Table 1ir in Table 1ir is promoted, and the heat of vaporization at this time reduces the humidity on the fuel surface, and Along with this, the entire fuel is 2&! The difference in temperature causes convection and C self-cooling progresses, thus actively suppressing the generation of fuel vapor.

In addition, at high speeds, conditions where percolation is difficult to occur are:
If the engine suction negative pressure is 6fl applied to the abend pipe 13, the difference from 115 is small (1'), and the above-mentioned effect will no longer occur.

As is clear from the above description, according to the present invention, during fitting after starting the engine and during low-speed driving (z+
+-l- Since there is air flow in all 3, the fuel vapor that has already been generated is quickly exhausted, and the newly generated fuel vapor is directly suppressed by the endothermic effect of promoting fuel vaporization.
111 and can effectively prevent burnout. Since it has a structure that utilizes the negative pressure of the venturi 13 and the venturi 8, it is not affected by the size of the engine room, etc., and the vaporized fuel in the float chamber 3 is also taken in and used for C combustion. Waste of fuel 1 There is no open chain of the popular horse riding, and there are few fluctuations in the air-fuel ratio of the mixture. Also,
The structure is also very simple.

[Brief explanation of the drawing]

The drawing shows an embodiment of the device according to the invention. 1... Carburetor, 2... Suction pipe, 3... Float chamber, 4... Float, 5... Side valve, 6... Fuel bonno, 1... Small bench 1, 8... large bend, lsu,
9...S11 valve, 10...Fuel passage, 11
...Main nozzle, 12...Air passage, 13...
Air bend pa 1'/', +4・l nonoclino.

Claims (1)

[Claims] In 6, an air vent pipe is connected between the venturi earth flow side and a part of the curved surface of the float chamber, and an opening J is provided at the upper part of the oil level of the float chamber and the part of the large bench L. The negative pressure port is connected through a passage, and the negative pressure is
Due to the difference between the two and the horns, the air vent pipe is
A burn prevention device for a carburetor, characterized in that an air circulation path is configured such that the air flows through a jet chamber and into a passage.