JPH0649751U - Engine with fuel circulation carburetor - Google Patents

Abstract

(57) [Summary] [Purpose] To simplify the starting operation of an engine equipped with a fuel circulation carburetor. [Configuration] Fuel pump driven by operating pressure of engine
18, a fuel chamber 7 that stores the fuel fed by the fuel pump and overflows the fuel from the weir 14 provided on the side surface to form a constant oil level, and a return passage that returns the overflowed fuel to the fuel tank 30. In the fuel circulation type carburetor including the fuel cell 13, the fuel pump 18 is installed so that at least one of the intake valve 20 and the discharge valve 21 is immersed in the fuel in the fuel tank 30.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention, a fuel pump driven by the operating pressure of the engine, a fuel chamber that stores the fuel delivered by the fuel pump and overflows the fuel from the weir provided on the side surface to form a constant oil level, The present invention relates to an engine equipped with a fuel circulation type carburetor, which has a return passage for returning the overflowed fuel to the fuel tank and circulates the fuel between the fuel chamber of the carburetor and the fuel tank during operation of the engine. .

[0002]

[Prior art]

 Many of the above fuel circulation type carburetors are installed in the engines of seasonal machines and vehicles. For example, seedling machines, rice transplanters, rice reapers, etc. can be used for at most 10 days within a year. If the fuel is left in operation for most of the rest of the year, the fuel remaining in the fuel chamber of the carburetor will deteriorate after being left for a long time.

To prevent this, in general, a small hole communicating with the return passage is provided at the bottom of the fuel chamber of the carburetor, and a small amount of fuel is constantly discharged from this small hole, or the small amount of fuel is discharged from the fuel chamber. The wire leading to the return passage is arranged so that a small amount of fuel is constantly discharged by the capillary action of this wire so that the fuel chamber is automatically emptied after the engine is stopped. Prior to this, fuel is supplied to the fuel chamber by a priming pump to fill the fuel chamber with fuel.

[0004]

[Problems of conventional technology]

 However, it is very troublesome to operate the priming pump every time the engine is started. The present invention aims to simplify the starting operation of the engine.

[0005]

According to the present invention, in the fuel circulation type carburetor, the fuel pump is installed such that at least one of the intake valve and the discharge valve is immersed in the fuel in the fuel tank. It is characterized by

[0006]

[Action]

 The fuel pump has a good valve function because the intake valve or the discharge valve is immersed in the fuel in the fuel tank. Therefore, when the fuel pump is driven by cranking the engine, the fuel is quickly discharged and sent to the carburetor. When the fuel chamber is filled with fuel, the fuel then overflows from the weir on the side surface of the fuel chamber, and a constant oil level is formed in the fuel chamber. The fuel overflowing from the fuel chamber is returned to the fuel tank through the return passage.

At the same time, due to engine cranking, the intake negative pressure acts on the fuel chamber through the main nozzle to suck the fuel in the chamber into the intake passage. Further, by closing a choke valve (not shown) at the time of starting, the intake air amount is limited, and a large amount of fuel is sucked into the engine by that amount, so that the starting is facilitated.

Therefore, the engine can be started only by cranking the engine with the recoil starter or the starter motor.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a fuel circulation type carburetor, and an intake passage 3 is provided through the carburetor main body 2. The intake passage 3 has an upstream side opening connected to an air cleaner (not shown), and a downstream side opening is connected to an engine. It is connected to the intake port of. Further, a throttle valve 4 for varying the effective diameter of the intake passage is arranged in the intake passage 3. A jet needle 5 projecting downward is attached to the throttle valve 4, and a tip end side of the jet needle 5 is fitted into a main nozzle 6 which is opened in a bottom wall of the intake passage 3 below the throttle valve 4.

A fuel chamber 7 is provided below the carburetor main body 2, and a boss 8 protruding downward from the carburetor main body 2 is accommodated in the fuel chamber 7. A passage 9 connected to the main nozzle 6 is provided in the boss 8, and the other end of the passage 9 is communicated below the oil level of the fuel chamber 7 via a main jet 10. A fuel receiver 12 is provided below the fuel inlet 11 opening into the fuel chamber 7, and the fuel discharged from the fuel inlet 11 is applied to the fuel receiver 12 to prevent bubbles from being generated in the fuel. is doing.

A return passage 13 is provided at a side portion of the fuel chamber 7. A weir 14 is provided between the fuel chamber 7 and the return passage 13 at a prescribed oil level level, and the fuel in the fuel chamber 7 overflows from the weir 14 and is discharged into the return passage 13 to allow the fuel chamber 7 to flow. A constant oil level is formed inside. The other end of the return passage is connected to a fuel tank via a pipe 35. Further, a wire 15 for discharging the fuel in the fuel chamber 7 to the return passage 13 by a capillary phenomenon is arranged between the fuel chamber 7 and the return passage 13 and always discharges a small amount of fuel to the return passage 13. Therefore, after the engine is stopped, the fuel in the fuel chamber 7 is automatically discharged.

Reference numeral 18 is a fuel pump. The pump 18 is a conventionally well-known diaphragm pump including a pump diaphragm 19, a suction valve 20, and a discharge valve 21, and is connected to a pressure chamber 23 formed on one side of the pump diaphragm 19 through a pipe 24 and an engine. Operating pressure, for example, in the two-cycle engine 22, the pressure in the crank chamber is caused to vibrate the pump diaphragm 19, and fuel is formed from the intake port 25 to the other side of the pump diaphragm 19 via the intake valve 20. The gas is sucked into the pump chamber 26, and is sent from the discharge valve 21 to the fuel chamber 7 of the carburetor through the discharge port 27 and the pipe 29.

Further, the fuel pump 18 is provided in the fuel tank 30 or at a side portion or a bottom portion of the fuel tank 30 so that at least one of the intake valve 20 and the discharge valve 21 is immersed below the oil level of the fuel tank 30. It is arranged. The suction port 25 of the fuel pump is connected to a filter 33 by a pipe 32, and the filter 33 moves to a low position along the inclination of the fuel tank 30 by its own weight.

The operation of the above embodiment will be described below. When the engine is cranked by the recoil starter or the starter motor to start the engine, the operating pressure generated in the crank chamber acts on the pressure chamber 23 of the fuel pump, and the fuel pump 18 is driven.

Since at least the intake valve 20 and the discharge valve 21 of the fuel pump 18 are immersed in the fuel, the valve portion is always filled with the fuel, and the fuel is promptly supplied to the carburetor 1 by driving the pump 18. Sent to. When the fuel chamber 7 is filled with the fuel, the fuel then overflows from the weir 14 on the side surface of the fuel chamber 7, and a constant oil level is formed in the fuel chamber 7. The fuel overflowing from the fuel chamber 7 is returned to the fuel tank 30 through the return passage 13.

At the same time, the intake negative pressure acts on the fuel chamber 7 through the main nozzle 6 by the cranking of the engine, and the fuel in the chamber is sucked into the intake passage 3. Further, by closing a choke valve (not shown) at the time of starting, the intake air amount is limited and a large amount of fuel is sucked into the engine by that amount, so that the starting is facilitated.

Therefore, the engine can be started only by cranking the engine with the recoil starter or the starter motor.

In the above embodiment, the fuel pump 18 is installed in the fuel tank 30. However, at the time of starting, at least one of the intake valve 20 and the discharge valve 21 of the fuel pump 18 is in the fuel tank 30. The fuel pump 18 can be installed outside the fuel tank 30 as long as it is immersed below the oil level.

[0019]

[Effect of device]

 As described above in detail, according to the present invention, the fuel pump driven by the operating pressure of the engine and the fuel delivered by the fuel pump are stored, and the fuel is overflowed from the weir provided on the side surface to a constant level. A fuel circulation system that has a fuel chamber that forms an oil level and a return passage that returns this overflowing fuel to the fuel tank so that the fuel circulates between the fuel chamber of the carburetor and the fuel tank during engine operation. In the carburetor, the fuel pump is installed so that at least the intake valve or the discharge valve is immersed in the fuel in the fuel tank when the engine is in the starting position, so the engine is cranked by the recoil starter or cell motor. Just by doing so, the fuel chamber of the carburetor is immediately filled with fuel and supplied to the engine. Therefore, the engine can be started easily.

Further, since it is not necessary to provide a priming pump which is generally used conventionally, it is possible to reduce the cost of the engine.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Fuel Circulation Vaporizer 3 Intake Passage 4 Throttle Valve 7 Fuel Chamber 13 Return Passage 18 Fuel Pump 20 Intake Valve 21 Discharge Valve 30 Fuel Tank

Claims (1)

[Scope of utility model registration request] 1. A fuel pump driven by operating pressure of an engine, a fuel chamber for storing fuel fed by the fuel pump, and overflowing fuel from a weir provided on a side surface to form a constant oil level. A fuel circulation type carburetor having a return passage for returning the overflowed fuel to the fuel tank and allowing the fuel to circulate between the fuel chamber of the carburetor and the fuel tank during engine operation. An engine provided with a fuel circulation type carburetor, wherein at least one of an intake valve and a discharge valve is installed so as to be immersed in the fuel in a fuel tank.