JPS63239347A - Accelerating fuel passage device for multiple carburetor - Google Patents

Abstract

PURPOSE:To keep off any leakage of fuel oil in plural carburetors with a single thermosensible valve, by setting up the thermosensible valve, opening or closing according to an ambient temperature, between the specified branch passage and a float chamber at one carburetor additionally provided with an accelerating pump. CONSTITUTION:At time of acceleration, since a push rod 14 is pressed downward and capacity in a pump case 9 is contacted, fuel in this pump case 9 is discharged to a suction passage 3a from a discharge passage 18 by way of a discharge valve 19 and an accelerating fuel nozzle 4a. And, this fuel is also fed to another discharge passage 27 from a connecting passage 29, and discharged to another suction passage 3b from an accelerating fuel nozzle 4b by way of a discharge valve 28. In this case, if an ambient temperature becomes more than the setting temperature, a thermosensible valve 22 opens. Consequently, the residual fuel flows back to a float chamber 5 of a first carburetor C1 via a branch passage 20 fitted with a check valve 21. Accordingly, any fuel leakage to these suction passages 3a and 3b is checked. Likewise discharge fuel is also put back to the float chamber 5 via the thermosensible valve 22.

Description

[Detailed Description of the Invention] A3 Objective of the Invention (1) Industrial Field of Application The present invention provides a method for pumping fuel oil in a float chamber to accelerating fuel nozzles individually arranged in the intake passage of each carburetor. The present invention relates to an acceleration fuel passage device for multiple carburetors in which acceleration pumps attached to one carburetor are connected to each other via individual discharge valves.

(2) Prior art Conventionally, such a device has been used, for example, in U.S. Pat.
It is publicly known from the publication No.

(3) Problems to be Solved by the Invention By the way, in order to prevent the fuel oil in the passage downstream of the acceleration pump from expanding as the temperature rises and leaking from the acceleration fuel nozzle into the intake passage. There is a technology in which a valve is opened when the ambient temperature exceeds a certain value to return fuel oil in a passage downstream of the accelerator pump to the float chamber (for example, U.S. Pat. No. 4,105,719). When considering application to conventional technology, it is simple to connect the passage leading to the accelerating fuel nozzle of each vaporizer to the float chamber of each vaporizer via a heat-sensitive valve that opens at a certain temperature or higher. I can think of. However, in this case, as many heat-sensitive valves as there are vaporizers are required. Furthermore, if the accelerator is operated repeatedly when the engine is stopped with the heat-sensitive valve open, the fuel oil pumped up from the float chamber of one carburetor will be sent to the float chamber of the other carburetor, causing a worst-case scenario. In this case, fuel oil may overflow from the float chamber into the intake passage in other carburetors, making it difficult to start, or the mixture may become richer when the engine is started, resulting in a higher concentration of hydrocarbons in the exhaust gas. .

The present invention has been made in view of the above circumstances, and provides an accelerating fuel for a multiple carburetor that prevents the leakage of fuel oil into the intake tract using the minimum number of heat-sensitive valves and solves the above-mentioned problems at startup. The purpose is to provide a passageway device.

B6 Structure of the Invention (Means for Solving 11 Problems) According to the present invention, the carburetor equipped with the acceleration pump is connected to the upstream side of the discharge valve in the passage connecting the acceleration pump and the acceleration fuel nozzle. A branch passage is provided, and a heat-sensitive valve that opens when the ambient temperature reaches a set temperature is interposed between the branch passage and the float chamber.

(2) Effect According to the above configuration, only one heat-sensitive valve is required, and when the heat-sensitive valve is opened, the fuel oil is refluxed only into the float chamber of one vaporizer, so the fuel oil is returned to the float chamber of one vaporizer. The indoor fuel oil level will not rise.

(3) Example Hereinafter, an example of the present invention will be described with reference to the drawings.
A first carburetor CI and a second carburetor configured by interconnecting
A multiple carburetor C is constituted by the carburetor C2, and the acceleration fuel nozzles 4a and 4b are connected to the intake passages 3a and 3b formed in the carburetor bodies 1a and lb of both carburetors CI and C2, respectively, in the intake direction. Each is arranged toward the downstream side. In addition, throttle valves (not shown) disposed upstream of the acceleration fuel nozzles 4a, 4b of both intake paths 3a, 3b are interlocked and connected.

The first carburetor CI is equipped with an acceleration pump 6 for pumping up the fuel oil in the float chamber 5 defined between the carburetor main body 1a and the float chamber body 2a and supplying it to each acceleration fuel nozzle 4a, 4b. be done. This acceleration pump 6 has a space formed by a float chamber body 2a and a cover 7 coupled thereto, and a diaphragm 8 whose outer periphery is sandwiched between the float chamber body 2a and the cover 7. It is divided into an air chamber 10. A return spring 11 is housed in the pump chamber 9, which urges the diaphragm 8 in a direction to expand the volume of the pump chamber 9.

Further, a guide tube 12 extending vertically is press-fitted and fixed into the float chamber body 2a with its lower end opened into the air chamber 10. A press rod 14 whose lower end abuts against a member 13 provided in the center of the diaphragm 8 is slid onto the guide tube 12, and the upper end of the press rod 14, which protrudes upward from the upper end of the guide tube 12, , pressing means linked to accelerator operation (not shown)
linked to and linked to. During the acceleration operation, the press rod 14 is pressed downward by the pressing means, and the volume of the pump chamber 9 is forcibly contracted, so that the fuel oil in the pump chamber 9 is discharged.

A suction passage 15 connecting the lower part of the float chamber 5 and the pump chamber 9 is bored in the cover 7 and the float chamber body 2a. A suction valve 16 is provided that allows flow only in the direction of inflow into the air.

In the first carburetor C1, a discharge passage 18 is formed in the carburetor body 1a, the float chamber body 2a, and the cover 7, and the discharge passage 18 communicates with the pump chamber 9 at one end.
An acceleration fuel nozzle 4a is fitted and connected to the other end. Moreover, a discharge valve 19 is disposed in the middle of the discharge passageway to allow only flow from the pump chamber 9 to the acceleration fuel nozzle 4a. Furthermore, a discharge passage 18 on the upstream side of the discharge valve 19 is provided in the float chamber body 2a and the carburetor body 1a.
A branch passage 20 connecting the upper part of the float chamber 5 and the upper part of the float chamber 5 is provided, and in this branch passage 20, in order from the upstream side,
A check valve 21 and a heat-sensitive valve 22 are provided. Check valve 21
allows flow only from the discharge passage 18 toward the float chamber 5. Further, the heat-sensitive valve 22 is connected to the branch passage 2
Housing 2 having a valve hole 23 communicating with the upstream part of 0
A bimetal piece 26 having a valve body 25 capable of closing the valve hole 23 is housed in the inside of the bimetal piece 26, and the bimetal piece 26 closes the valve hole 23 with the valve body 25 when the ambient temperature is lower than a set temperature, for example, 15 degrees Celsius. When the atmospheric temperature becomes equal to or higher than the set temperature, the valve body 25 is separated from the valve hole 23 and the valve is in an open position.

That is, the heat-sensitive valve 22 is closed when the ambient temperature is less than the set temperature, and is opened to open the branch passage 20 when the ambient temperature becomes equal to or higher than the set temperature.

In the second carburetor C2, the float chamber body 2b and the carburetor body 1b are provided with a discharge passage 27 for fitting and connecting the accelerating fuel nozzle 4b.
A discharge valve 28 that only allows flow toward the acceleration fuel nozzle 4b is disposed in the middle of the acceleration fuel nozzle 7. Also, the first vaporizer C
The first discharge passage 18 and the discharge passage 27 of the second vaporizer C2 are connected by a communication pipe 30 forming a communication passage 29. One end of this communication pipe 30 is connected to the float chamber body 2a of the first carburetor C1 so that one end of the communication passage 29 communicates with the upstream side of the check valve 19 in the discharge passage 18, and the other end is connected to the float chamber body 2a of the first vaporizer C1. The other end is connected to the float chamber body 2b of the second carburetor C2 so as to communicate with the discharge passage 27.

Next, the operation of this embodiment will be explained. During a sudden acceleration operation, the volume of the pump chamber 9 contracts as the press rod 14 is pressed downward, and the fuel oil in the pump chamber 9 flows into the discharge passage 18. The fuel is discharged, passes through the discharge valve 19, and is then transferred to the acceleration fuel nozzle 4.
It is discharged from a to the intake passage 3, and is also supplied from the communication passage 29 to the discharge passage 27, passes through the discharge valve 28, and is discharged from the acceleration fuel nozzle 4b to the intake passage 3b, thereby generating fuel in both carburetors C1 and C2. The mixture concentration is enriched. Moreover, the communication passage 29 is located upstream of the discharge passage 1 from the discharge valve 19.
8, the pressure in the discharge passage 18.27 on the upstream side of the discharge valve 19.28 is equalized, and the acceleration fuel nozzle 4a
, 4b can be made equal.

By the way, when the ambient temperature exceeds the set temperature, the heat-sensitive valve 2
2 opens. Therefore, when the acceleration pump 6 is not operating, the pump chamber 9, the discharge passage 18, the branch passage 20,
In response to an increase in pressure due to the expansion of the fuel oil accumulated in the communication passage 29 and the discharge passage 27, a part of the fuel oil is returned to the float chamber 5 of the first vaporizer CI via the heat-sensitive valve 22,
Fuel oil leakage from the acceleration fuel nozzles 4a, 4b to the intake passages 3a, 3b can be suppressed as much as possible.

Further, assuming that the accelerator is operated when the engine is stopped and the ambient temperature is higher than the set temperature of the heat-sensitive valve 22, in this case, the accelerator pump 6 will operate in response to the accelerator operation and fuel oil will flow into the discharge passage 20. However, the discharged fuel oil is returned to the float chamber 5 via the heat-sensitive valve 22. Therefore, the amount of fuel oil in the float chamber of the second carburetor C2 does not increase, resulting in poor starting due to overflow into the intake tract, or the concentration of the mixture becoming too rich at the time of starting, resulting in an increase in the hydrocarbon concentration in the exhaust gas. It never gets darker.

Moreover, since the heat-sensitive valve 22 is provided only in the first vaporizer C1, it is possible to contribute to a reduction in the number of parts and, accordingly, to a simplification of the structure.

C1 Effects of the Invention As described above, according to the present invention, the carburetor equipped with the acceleration pump is provided with a branch passage that communicates with the upstream side of the discharge valve of the passage connecting the acceleration pump and the acceleration fuel nozzle, A heat-sensitive valve that opens when the ambient temperature exceeds a set temperature is installed between the branch passage and the float chamber, so a single heat-sensitive valve can be used to operate multiple vaporizers. It is possible to prevent fuel oil from leaking into the intake tract at high temperatures, contributing to a reduction in the number of parts and simplification of the structure.

Moreover, when the heat-sensitive valve is opened, fuel oil flows back into only the float chamber of one carburetor, and fuel oil is not sent to the float chambers of other carburetors, making it difficult to start or when starting. The mixture concentration will not become too rich.

[Brief explanation of the drawing]

The drawing is a vertical cross-sectional view of only the essential parts of an embodiment of the present invention.

Claims (1)

[Claims] An acceleration pump attached to one carburetor for pumping up fuel oil from a float chamber is connected to an acceleration fuel nozzle individually arranged in the intake path of each carburetor via an individual discharge valve. In the accelerating fuel passage device for a multiple carburetor, the carburetor equipped with the accelerating pump is provided with a branch passage communicating upstream of the discharge valve of the passage connecting the accelerating pump and the accelerating fuel nozzle, and the branch passage An accelerating fuel passage device for a multiple carburetor, characterized in that a heat-sensitive valve that opens when the ambient temperature reaches a set temperature or more is interposed between the passage and the float chamber.