JPS59215944A - Overflow device of carbureter - Google Patents

Abstract

PURPOSE:To prevent fuel form excessive passage through a nozzle port for facilitating start of an engine when fuel is suppliecl to a combustion chamber by providing a manual pump in a fuel supply path and closing a switch valve provided in a nozzle path to be interlocked with the pressurizing operation of said pump. CONSTITUTION:When a pump chamber 69 of a manual pump 67 is press operated in starting an engine, fuel is sucked form a tank chamber 3 to pass through a fuel supply path 13, push a controlling valve 15 open and enter a combustion chamber 9. Pressure applied then to the fuel supply path 13 enters a cyinder form a pressurizing path 53 to move a valve body righ and close a nozzle path 37. Thus, no fuel flows out of a nozzle port 41. On the other hand, when the combustion chamber 9 is filled with fuel, pushes a check valve 65 open and circulates from an overflow path 61 to the fuel tank 3. Thereafter, when the engine is operated into the normal running, a diaphragm pump 17 is operated to supply fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for preventing excessive supply of fuel to the fuel chamber of a carburetor when a manual pump installed in a fuel supply path for supplying fuel from a fuel tank to the fuel chamber of a carburetor is operated. This relates to an overflow device of a carburetor for discharging fuel that has been burned.

Conventionally, when starting an engine, the amount of fuel supplied is increased and the fuel is burned! In order to increase the 31 concentration and make it easier to start the engine, a manual pump was installed in the fuel supply path, but the fuel
The fuel pumped into the PA'ffl flows from the nozzle passage to the nozzle port, resulting in an excessive fuel concentration, which may conversely result in failure to start the engine. For this reason, as shown in Figures 3 and 4, an overflow valve is installed that is linked to a control valve that opens due to the pressure applied to the fuel chamber when the manual pump is activated. Excess fuel was then returned to the fuel tank via this overflow passage, but even in this case, the nozzle passage remained open, so the pressure in the fuel chamber caused it to flow out from the nozzle opening. Excess fuel could not be regulated.

The present invention provides a pressurized manual pump in the fuel supply path, and an on-off valve provided in the nozzle passage that closes in conjunction with the pressurizing operation of the manual pump. When fuel is supplied to the fuel chamber by operating the manual pump,
In addition to preventing excess fuel from flowing into the nozzle port and making it easier to start the engine, a check valve that opens and closes at a predetermined pressure C' is provided in the overflow passage to prevent excess fuel from flowing through the overflow passage. The purpose is to return the fuel to the fuel tank through the fuel tank, and to prevent the atmospheric pressure inside the fuel tank from affecting the fuel chamber of the carburetor.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 and 2, 1 indicates a carburetor and 3 indicates a fuel tank. The vaporizer 1 is constructed as follows. That is, 5 is a diaphragm installed at the bottom of the main body 7, and a fuel chamber 9 is located above. A chamber 11 communicating with the atmosphere through a ventilation hole 10 is formed below. 13 is control valve 1
A diaphragm pump 17 is installed in the middle of the fuel supply path that communicates with the fuel chamber 9 via a diaphragm 18.
The pressurized chamber 19 behind the diaphragm 1ε3 is connected to the engine crankcase (not shown) and operates in response to changes in pressure within the crankcase, causing the diaphragm 1ε3 to swing and the check valve 21 to open.
．． Pump chamber 23. Fuel is sent through the check valve 25. 27 is an arm that supports the lower end of the control valve 15 at one end, is pivotably supported by a shaft 29, and is biased by the ammunition 31 in the direction of closing the ffi+l 1 valve 15;
There is. Reference numeral 33 denotes an actuating piece fixed to the diaphragm 5, the upper end of which is in contact with the other end of the arm 27. Reference numeral 37 denotes a nozzle passage that communicates the fuel chamber 9 with a nozzle port 41 that opens into an air flow path 39 that communicates with an intake port (not shown) of the engine.

43 is a needle valve for adjusting and covering the nozzle 41.

45 is a needle valve that adjusts the nozzle passage 37. 4
7 is an on-off valve that opens and closes the nozzle passage 37;
It consists of a cylinder part 49 that communicates with the valve 7, and a valve body 51 that can be freely opened within the cylinder part 49. Reference numeral 53 denotes a pressurizing passage that communicates with the fuel supply passage 13 and the cylinder part 49;
1 and pressurizes the C valve body 51 against the bullet 55.
By pressing rightward in the figure, the valve hole 59 is closed with the valve portion 57 at the tip. 61 is the A-bar 3 communicating with the fuel chamber 9.
- one flow channel communicating with the fuel tank 3 via an overflow vibro 3; Reference numeral 65 designates a check valve provided in the overflow passage 61, which communicates only in the direction of the fuel tank 3 when a predetermined pressure is applied.

Reference numeral 67 denotes a rubber manual pump installed in the fuel supply passage 13 that communicates the fuel chamber 9 and the fuel tank 3. Filter 73, check valve 7
It is connected to 5. 77 is a lid of the injection lower 9 of the fuel tank 3, and a check valve 81 is provided inside.

In the above embodiment, when starting the engine, when the pump chamber 69 of the manual pump 67 is pressed to operate, fuel is sucked from the tank chamber 3 and passes through the fuel supply path 13 to the control valve 15. Push it open and enter the fuel chamber 9. At this time, the pressure applied to the fuel supply path 13 enters the cylinder part 49 from the pressurizing path 53, moves the valve body 51 to the right in FIG. 2, and closes the nozzle passage 37. No fuel will leak out. When the fuel 4-FA 9 is filled with fuel, the check valve 65 is pressed and the fuel is returned to the fuel tank 3 through the overflow passage 61. When the engine is started and normal operation is performed, the diaphragm pump 17 operates to supply fuel.

Since the present invention has the configuration as described in the claims,
When starting the engine, a manual pump supplies fuel to the carburetor to enrich the mixture and make it easier to start.It also prevents excessive fuel from flowing out of the nozzle port and making starting difficult. In addition, when the pressure inside the fuel tank 3 rises in the summer, the check valve 65 prevents the fuel chamber 9 from being pressurized from the overflow passage 61 or the fuel from flowing back. By setting the opening negative pressure of the valve 65 to be lower than the opening negative pressure of the check valve 81, the pressure in the fuel chamber 9 can be prevented from becoming negative even when the inside of the fuel tank 3 becomes negative pressure. This allows the engine to start smoothly.

3 and 4 show a conventional carburetor, in which an overflow valve 83 is provided which opens and closes the overflow passage 61 in conjunction with the control valve 15, but the nozzle passage 37
There is no on-off valve installed to open and close the valve. Therefore, when the manual pump is operated, excess fuel flows out from the nozzle lower 11.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented in other embodiments as well. Further, the symbols shown in the claims do not limit the technical scope of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an embodiment of the present invention, Fig. 2 is an enlarged side sectional view of the same main part, Fig. 3 is a side sectional view of the conventional example, and Fig. 4 is an enlarged side sectional view of the same main part. It is a diagram. <Explanation of symbols representing main parts of the drawings) 1... Carburetor 3... Fuel tank 9... Fuel chamber
13...Fuel supply passage 37...Nozzle passage
41... Nozzle port 47... Open/close valve 61
... Overflow passage 65 ... Check valve 6
7...Manual pump patent Applicant: Komatsu Zenoah Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Procedural amendment (Gal culm) September 27, 1980 Commissioner of the Patent Office Kazuo Wakasugi 1, Display of the case 1982 Patent Application No. 89092 2, Title of the invention A-bar flow device 3 for a vaporizer, Relationship with the case of the person making the amendment Patent applicant's residence (Residence) 2-142 Sakuragaoka, Higashiyamato City, Tokyo Address 1 Name: Komatsu Zenoah Co., Ltd. Representative: Isamu Minami 4, Agent address: 1-2-3 Toranomon, Minato-ku, Tokyo 105
Toranomon No. 5 Building 5th Floor Telephone: Tokyo (504) 3075, 3076, 3077
No. 1-6, Subject of amendment (1) Application (2) Specification 7, Contents of amendment <1) What about the application? ! (II) There is no change in the content to be written) (2) Illustrated copy of the specification (Il) 8. List of attached documents (1) Application form (1 copy) (2) Specification
1 letter 2-

Claims (1)

[Claims] A manual pump 67 is installed in the fuel supply path 13 for supplying fuel from the fuel tank 3 to the combustion chamber 9 of the carburetor 1, and a manual pump 67 is installed between the fuel chamber 9 and the nozzle port 41. An on-off valve 47 is provided in the nozzle passage 37 that communicates with the fuel chamber 9, and a check valve 65 is provided in the overflow passage 61 that communicates the fuel chamber 9 and the fuel tank 3 with each other at a predetermined pressure. , the on-off valve 47 is connected to the manual pump 6
7. An over-puff device for a vaporizer, characterized in that the nozzle passage 37 is closed in conjunction with the pressurizing operation of the vaporizer.