JPH0457864B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Industrial Application Field The present invention provides an accelerating fuel nozzle that is attached to one specific carburetor and that The present invention relates to an acceleration fuel passage device for a multiple carburetor in which acceleration pumps capable of pumping up fuel oil from float chambers of the carburetors are connected via individual discharge valves.

(2) Conventional technology Conventionally, such a device has been used, for example, in
It is publicly known from Publication No. 32180 and the like.

(3) Problems to be Solved by the Invention By the way, in order to prevent fuel oil in the passage downstream of the accelerator pump from expanding as the temperature rises and leaking from the accelerating fuel nozzle into the intake passage, the atmospheric temperature has to be lowered. There is a technology that opens a valve when the accelerator pump exceeds a certain value and returns the fuel oil in the passage downstream of the accelerator pump to the float chamber (for example, the U.S. patent
4105719 and Japanese Patent Application Laid-Open No. 1983-109046), when considering applying such technology to the above-mentioned conventional technology, it is necessary to heat the passage leading to the accelerating fuel nozzle of each carburetor at a temperature higher than a certain temperature. A simple idea would be to connect each vaporizer to the float chamber via a thermally sensitive valve that opens. However, doing so would require as many heat-sensitive valves as there are vaporizers,
Furthermore, if the accelerator is operated repeatedly while the engine is stopped with the heat-sensitive valve open, the fuel oil pumped up from the float chamber of one carburetor will also be sent to the float chamber of the other carburetor. ,
In the worst case scenario, fuel oil may overflow from the float chamber into the intake passage in another carburetor, 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. do.

The present invention has been made in view of such circumstances, and uses a heat-sensitive valve provided in one specific vaporizer to
It is an object of the present invention to provide an accelerating fuel passage device for multiple carburetors, which has a simple structure, prevents leakage of fuel oil into the intake passages of a plurality of carburetors, and solves the above-mentioned problems at startup.

B. Structure of the Invention (1) Means for Solving the Problems According to the present invention, in order to achieve the above object, only one specific vaporizer equipped with an accelerator pump among a plurality of vaporizers is equipped with an accelerator pump and an accelerator pump. A branch passage is provided that branches from the upstream side of the discharge valve of the passage connecting the accelerating fuel nozzles and connects to the float chamber of the specific one carburetor, and in the branch passage, the atmosphere temperature becomes higher than the set temperature. A heat-sensitive valve is installed that opens depending on the temperature.

(2) Effect When the accelerator pump is inactive at high temperatures, by opening the single heat-sensitive valve, leakage of fuel oil from each accelerating fuel nozzle of the plurality of carburetors to the corresponding intake passage is suppressed to the utmost.

Furthermore, even if the accelerator is operated while the engine is stopped at high temperatures, the opening of the single heat-sensitive valve will cause the fuel oil pumped up by the accelerator pump from the float chamber of one specific carburetor to flow at the same rate. Since the oil is returned only to the float chamber and is not sent to the float chambers of other carburetors, the oil level in the float chambers of the other carburetors may rise and overflow into the intake tract, causing starting problems. Alternatively, there is no risk that the mixture concentration will become too rich at the time of startup.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A multiple carburetor C is constituted by the carburetor C1 and the second carburetor C2, and intake passages 3a, 3 are provided in the carburetor bodies 1a, 1b of both the carburetors C1, C2.
Accelerating fuel nozzles 4a and 4b are respectively disposed toward the downstream side in the intake direction. In addition, throttle valves (not shown) disposed upstream of the acceleration fuel nozzles 4a, 4b in both intake paths 3a, 3b are interlocked and connected.

The first carburetor C1 pumps up the fuel oil in the float chamber 5 defined between the carburetor main body 1a and the float chamber body 2a, and pumps the fuel oil into each accelerating fuel nozzle 4a, 4b.
An acceleration pump 6 is attached for supplying the fuel to the fuel. 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. In the pump room 9,
A return spring 11 that biases the diaphragm 8 in a direction to expand the volume of the pump chamber 9 is housed.
Further, a guide cylinder 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 receiving member 13 provided at the center of the diaphragm 8 is slid onto the guide tube 12, and the upper end of the press rod 14, which projects upward from the upper end of the guide tube 12, linked to a pressing means (not shown) linked to accelerator operation,
Concatenated. 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 vaporizer C1, the vaporizer main body 1a, the float chamber body 2a, and the cover 7 have a pump chamber 9.
A discharge passage 18 is bored, and the other end of this discharge passage 18 is fitted with and connected to the acceleration fuel nozzle 4a. Moreover, a discharge valve 19 is disposed in the middle of the discharge passage 18 to allow only flow from the pump chamber 9 toward the acceleration fuel nozzle 4a. Furthermore, a branch passage 20 connecting the discharge passage 18 upstream of the discharge valve 19 and the upper part of the float chamber 5 is provided in the float chamber body 2a and the carburetor body 1a. are, in order from the upstream side, a check valve 21 and a heat-sensitive valve 2.
2 is arranged. The check valve 21 allows only flow from the discharge passage 18 toward the float chamber 5 . The heat-sensitive valve 22 also has a housing 2 having a valve hole 23 communicating with the upstream portion of the branch passage 20.
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 ambient 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 opened. That is, the heat-sensitive valve 22 is in a closed state when the ambient temperature is less than the set temperature, and opens to open the branch passage 20 when the ambient temperature becomes equal to or higher than the set temperature.

In the second carburetor C2, a discharge passage 27 for fitting and connecting the acceleration fuel nozzle 4b is bored in the float chamber body 2b and the carburetor body 1b. Discharge valve 2 that only allows flow toward the fuel nozzle 4b
8 are arranged. Further, the discharge passage 18 of the first vaporizer C1 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. A second carburetor C has the other end communicated with the discharge passage 27.
It is connected to the second float chamber body 2b.

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 from the acceleration fuel nozzle 4a to the intake passage 3 via the discharge valve 19, and is also discharged from the communication passage 29 to the discharge passage 2.
7 and is discharged from the acceleration fuel nozzle 4b to the intake passage 3b via the discharge valve 28, thereby increasing the concentration of the air-fuel mixture produced in both the carburetors C1 and C2. Moreover, since the communication passage 29 communicates with the discharge passage 18 on the upstream side of the discharge valve 19, the discharge valves 19, 28
The pressures in the discharge passages 18 and 27 on the upstream side can be equalized, and both fuels discharged from the acceleration fuel nozzles 4a and 4b can be equalized.

By the way, when the ambient temperature exceeds the set temperature,
The heat-sensitive valve 22 opens. Therefore, when the acceleration pump 6 is not operating, the pressure increases due to the expansion of the fuel oil accumulated in the pump chamber 9, the discharge passage 18, the branch passage 20, the communication passage 29, and the discharge passage 27. This fuel oil flows back into the float chamber 5 of the first carburetor C1 via the heat-sensitive valve 22, and 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 passes through the heat-sensitive valve 22.
It is returned to the float chamber 5 through. Therefore, the second
In the carburetor C2, the amount of fuel oil in the float chamber does not increase, and there is no possibility of starting failure due to overflow to the intake tract, or that the mixture concentration becomes too rich at the time of starting, resulting in an increase in the hydrocarbon concentration in the exhaust gas.

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.

C. Effects of the Invention As described above, according to the present invention, the connection between the acceleration pump and the accelerating fuel nozzle is established only in one specific carburetor equipped with an accelerating pump among the plurality of vaporizers constituting the multiple carburetor. A branch passage is provided that branches from the upstream side of the discharge valve of the passage and connects to the float chamber of the specific one vaporizer, and the branch passage opens when the ambient temperature becomes equal to or higher than a set temperature. Since a heat-sensitive valve is installed, when the accelerator pump is inactive at high temperatures, opening of the single heat-sensitive valve will cause
It is possible to minimize the leakage of fuel oil from each accelerating fuel nozzle of multiple carburetors to the corresponding intake tract, and even if the accelerator is operated with the engine stopped at high temperatures, the single heat-sensitive valve will not open. Therefore, the fuel oil pumped up by the accelerator pump from the float chamber of a specific carburetor flows back only to that float chamber and is not sent to the float chambers of other carburetors. There is no risk that starting will become difficult due to a rise in the oil level in the float chamber of the carburetor, or that the mixture concentration will become too rich at the time of starting.
Moreover, the problem of multiple vaporizers at such high temperatures can be solved without any problem by using the branch passage and a single heat-sensitive valve provided only in one specific vaporizer. Since the passage and the heat-sensitive valve can be used in common for a plurality of vaporizers, the number of parts can be reduced and the structure can be simplified, which can contribute to cost reduction and improved maintainability.

[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. 3a, 3b...Intake path, 4a, 4b...Acceleration fuel nozzle, 5...Float chamber, 6...Acceleration pump, 19,
28...discharge valve, 20...branch passage, C...multiple vaporizer, C1, C2... vaporizer.

Claims (1)

[Claims] 1 Intake paths 3a, 3b of multiple carburetors C1, C2
Accelerating fuel nozzles 4 each individually arranged in
a, 4b, an acceleration pump 6 attached to a specific carburetor C1 and capable of pumping up the fuel oil in the float chamber 5 of the carburetor C1 is connected to the individual discharge valves 19, 2.
8, the plurality of carburetors C1,
Only to the specific one carburetor C1 among C2, the passage 18 connecting between the acceleration pump 6 and the acceleration fuel nozzle 4a is branched from the upstream side of the discharge valve 19 to the float chamber 5 of the specific carburetor C1. Accelerating fuel for a multiple vaporizer, characterized in that a continuous branch passage 20 is provided, and a heat-sensitive valve 22 that opens when the ambient temperature becomes higher than a set temperature is interposed in the branch passage 20. Passage device.