JPS6024929Y2 - carburetor fuel system - Google Patents

Description

[Detailed description of the invention] This invention relates to a fuel system for a carburetor for an engine such as an agricultural machinery engine, which has a short usage period and a relatively long storage period. The purpose is to prevent problems that may occur when restarting the engine.

If an engine with gasoline remaining in the float chamber of the carburetor is stored for a long period of time, the gasoline will oxidize and turn into gum, which will clog jets and bleed holes, making engine operation, especially starting, difficult.

In view of the above points, the present invention provides a drain cock, a heat-sensitive valve, a drain tank, and a fuel return pump in series in the fuel system of a normal carburetor, and connects the fuel cock, drain cock, and engine switch of the fuel system. When the engine is stopped for a short time, the fuel is held in the float chamber, and when the engine is stopped for a short time, the fuel in the float chamber is drained into the drain tank and returned to the fuel tank during the next operation. If the engine is stopped for a long time, the fuel is allowed to evaporate naturally in the drain tank, and the fuel is not allowed to remain in the float chamber for a long time when the engine is stopped.

Next, embodiments of the present invention will be described based on the drawings.

The figure is a schematic diagram of the fuel system of the carburetor of the present invention. In the figure, 1 is the intake cylinder of the carburetor, 2 is the slot valve, and 3 is the main nozzle. The fuel in the fuel tank 4 is floated through the fuel cock 5 and the float valve 6. It is supplied into the chamber 7.

The present invention includes a drain cock 8, a heat-sensitive valve 9 that opens below a set temperature, and a drain tank 10, which operate in connection with engine operation, at the end of the fuel system of the carburetor, that is, at the bottom of the float chamber 7. A fuel return pump 11 is provided in series, and the fuel cocks 5, 8 and the engine switch 12 are connected so that the fuel cock 5 and drain cock 8 are opened and closed alternately.
are interlocked by an interlocking mechanism 13.

The drain cock 8 is provided at the top of a drain pipe 14 connecting the bottom of the float chamber 7 and the top of the drain tank 10, and is set to close when the engine switch 12 is in the ON state, that is, when the fuel cock 5 is open.

The heat-sensitive valve 9 is a valve made of bimetal or the like, and its operating heat source is ambient temperature, an electric heater, a heat pipe, or the like, and is provided downstream of the cock 8 of the drain pipe 14 .

The drain tank 10 has a volume sufficient to accommodate the fuel in the float chamber 7, and is provided with a vent hole 15 on its top plate and a fuel return pipe 16 that opens at the top of the fuel tank at its bottom. 11 is provided at an appropriate position on this pipe 16.

This pump 11 may be of a mechanical type or an electric type, but the embodiment shown in the figure is a negative pressure pump, and is operated by the pulsation of negative pressure in the suction pipe acting through the negative pressure passage 17.

In the fuel system of the carburetor of the present invention configured as described above, during engine startup and operation, the engine switch 12 is turned ON, the fuel cock 5 is opened, and the drain cock 8 is closed by the simultaneous operation of the interlocking mechanism 13. Therefore, the engine continues to operate using the same carburetor fuel system as before.

During this time, the heat-sensitive valve 9 is also activated by heat from the engine, and is soon closed.

In this state, when you stop the engine, the engine switch 12 turns OFF, and at the same time, the fuel cock 5 closes and the drain cock 8 opens, but the temperature of the downstream heat-sensitive valve 9 remains below the set temperature even if the engine stops. The fuel in the float chamber is drained from drain tank 1 because it remains closed until
It is held in the float chamber 7 without being extracted into the float chamber 7.

In this case, even when the engine temperature is used, the heat acting on the heat-sensitive valve 9 is retained as residual heat for a considerable time, so if the engine is stopped for a short time, there is no need to wait for fuel charging when restarting, and the engine can be started immediately. It is.

When the engine is stopped for a long time and the engine cools down, and the temperature of the heat-sensitive valve 9 drops below the set temperature, the valve 9 opens and the fuel in the flow chamber is drained into the tank 10 through the drain pipe 14, leaving the float chamber 7 empty. Therefore, even if the engine is stored or left as it is, there will be no problems caused by the deterioration of the fuel in the float chamber as described above.

Furthermore, if the engine is used for a short period of time, the fuel drained into the drain tank 10 is returned to the fuel tank 4 through the return pipe 16 by the negative pressure pump 11 at the beginning of operation, but if the fuel is stored or left unattended for a long time. If it does, it will be dissipated into the atmosphere by natural evaporation.

In the above embodiment, the operating negative pressure of the fuel return pump 11 is directly taken in through the passage 17, so the pump 11 is operated while the engine is running. A heat-sensitive valve 18 made of bimetal that is set to open at a low temperature and close at a high temperature is provided, or a solenoid valve 1 that closes when not energized is provided.
9, the excitation circuit of this valve is connected to the dynamo 21 via a bimetallic switch 20 that turns off at high temperature, and the bimetallic switch 20 is heated by a heating wire 22 branched from the dynamo side. No matter which valve 19 is used, the valve will be open for a considerable period of time at the beginning of engine operation, and will close when the bimetal is activated.
1 can be activated.

As mentioned above, when the present invention is used, the operation is the same as before. If the engine is stopped for a short time, fuel is retained in the float chamber in preparation for restarting, and if the engine is stopped for a long time, the fuel in the float chamber is automatically drained. The fuel in the drain tank is then drained, leaving the float chamber empty, eliminating the predisposition to the above-mentioned failures even when stored or left unused for long periods of time.Furthermore, the fuel in the drain tank that has been drained out also allows the engine to operate at shorter days. If so, it will be returned to the fuel tank at the beginning of the operation, etc.
This type of vaporizer provides excellent effects.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an embodiment of the fuel system of the carburetor of the present invention. 1... Intake cylinder of carburetor, 2... Throttle valve, 3... Main nozzle, 4...
...Fuel tank, 5...Fuel cock, 6...
...Float valve, 7...Float chamber, 8
... Drain cock, 9 ... Heat sensitive valve, 10 ... Drain tank, 11 ... Fuel return pump, 12 ... Engine switch, 1
3...Interlocking mechanism, 14...Drain pipe, 15...Vent hole, 16...Fuel return pipe, 17...Negative pressure aisle.

Claims (1)

[Scope of utility model registration request] The fuel system of the carburetor consists of a fuel tank, a fuel cock, a float valve, and a float chamber, and a drain cock.
A heat-sensitive valve that opens below a set temperature, a drain tank, and a fuel return pump that operates related to engine operation are installed in series, and these cocks and the engine switch are linked so that the fuel cock and drain cock open and close alternately. The fuel system of the carburetor.