JPH0714143U - Circulating vaporizer - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a circulating vaporizer in which the fuel level is stable and the fuel supply is stable even when the vaporizer is tilted. [Configuration] Fuel pump 25 that is driven while the engine is operating
To supply the fuel to the fuel chamber 6, and when the oil level in the chamber 6 reaches a predetermined height, the fuel overflows to form a constant oil level, and the fuel overflowing from the chamber 6 is passed through the return passage 15 to the fuel tank. In the fuel circulation type carburetor which is returned to 19, a plate 22 whose upper surface is formed to have an oil level is provided in the fuel chamber 6, and an overflow hole 23 is provided in the plate upper surface and the overflow hole 23 is provided. The main nozzle boss 7 is inserted into the inside, and the fuel is overflowed from the gap between the main nozzle boss 7 and the overflow hole 23.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circulation type vaporizer used for small engines such as brush cutters, cultivators and power sprayers.

[0002]

[Prior art]

 2. Description of the Related Art In a conventional circulation type carburetor, as shown in FIG. 2, a carburetor body 51 and a chamber case 52 form a fuel chamber 53, and a return passage 54 is provided at a side portion of the fuel chamber 53 and the fuel chamber 53 and the return chamber are connected to each other. A weir 55 is provided between the passages 54, and the fuel fed from the fuel pump 56 is overflowed from the weirs 55 to form a constant oil level Hs in the fuel chamber 53, and the overflowed fuel is fed to the return passage 54. After that, it is returned to the fuel tank 57. Further, the carburetor body 51 is provided with an air vent passage 58 connected to the air layer of the fuel chamber 53.

[0003]

[Problems of conventional technology]

 In the circulation type carburetor having the above structure, when the carburetor is inclined toward the return passage 54 side, the position of the weir 55 is lowered and the oil level in the fuel chamber 53 is lowered like H1 to prevent the engine from entering the engine. If the fuel supply amount is reduced or if the vehicle is further inclined, there is a drawback that the main jet 59 is exposed on the oil surface and causes an engine stall. Further, in the case of inclining in the opposite direction, the position of the weir 55 is located above, so the oil level rises as shown by H2 and the fuel supply amount to the engine increases. In this way, when the carburetor is tilted, the fuel supply amount to the engine changes, so the rotation of the engine fluctuates, and workability deteriorates.

An object of the present invention is to provide a circulation type carburetor in which the fluctuation of the oil level is small even when the carburetor is tilted and the fuel is stably supplied.

[0005]

[Technical Means for Solving the Problems] In the present invention, a plate whose upper surface is formed at the oil level is provided in the fuel chamber, and an overflow hole is provided in the upper surface of the plate. The main nozzle boss is inserted, and the fuel is allowed to overflow from the gap between the main nozzle boss and the overflow hole.

[0006]

[Action]

 According to the above configuration, the fuel is filled up to the upper surface of the plate in the fuel chamber, and the excessively supplied fuel overflows from the gap between the overflow hole provided on the upper surface of the plate and the main nozzle boss. Flows over the upper side of the plate and is discharged to the return passage and returned to the fuel tank. As a result, when the engine is in operation, the fuel chamber is constantly filled with fuel, and even if the circulating carburetor tilts, air does not flow into the fuel chamber through the overflow hole, so that the fuel inside the fuel chamber The amount of stored water hardly changes, and fluctuations in the oil level are suppressed. Therefore, the amount of fuel supplied to the engine hardly changes even when the vehicle is leaning, and rotational fluctuation due to the attitude of the engine is reduced.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing an embodiment of the present invention. Reference numeral 1 is a circulation type carburetor, and an intake passage 3 is provided in a body 2 thereof, an upstream side of the intake passage 3 is connected to an air cleaner (not shown), and a downstream side is connected to an intake port (not shown). A throttle valve 4 is provided in the intake passage 3 so as to be capable of advancing and retracting in a substantially orthogonal direction, and the effective diameter of the intake passage 3 is controlled.

A fuel chamber 6 is formed below the intake passage 3 by the carburetor body 2 and the chamber case 5, and a main nozzle boss 7 is projected from the body 2 into the fuel chamber 6. A main nozzle accommodating hole 9 is bored in the main nozzle boss 7, and a main nozzle 10 is accommodated in the accommodating hole 9 and is fixed by a main jet 11 screwed to the lower end of the boss 7. The upper end opening of the main nozzle 10 faces the intake passage 2, and the lower end opening communicates with the main jet 11 below the oil level of the fuel chamber 6. A jet needle 13 is suspended from the throttle valve 4, and the jet needle 13 is inserted into the main nozzle 10 to control the opening area of the main nozzle 10 as the throttle valve 4 advances and retracts.

The chamber case 5 is provided with a return passage 15 at a side portion of the fuel chamber 6, and a wire 17 for constantly discharging a small amount of fuel from the fuel chamber 6 to the return passage 15 is arranged between them. After the engine is stopped, the fuel chamber 6 is automatically emptied. The return passage 15 is connected to a fuel tank 19 via a pipe 18. Further, the vaporizer body 7 is provided with an air vent passage 20 for communicating the air layer above the fuel chamber 6 to the atmospheric pressure.

Between the carburetor body 2 and the chamber case 5, a plate 22 having an upper surface formed to have an oil level is sandwiched. An overflow hole 23 is provided on the upper surface of the plate 22, and the main nozzle boss 7 is inserted into the overflow hole 23. Therefore, the excess amount of fuel supplied into the fuel chamber 6 overflows from the gap between the overflow hole 23 and the main nozzle boss 7, and is returned to the fuel tank 19 through the return passage 15. Reference numeral 24 is a passage for guiding the fuel overflowing to the opposite side of the return passage 15 to the return passage 15.

The circulation type carburetor 1 is provided with a fuel pump 25 driven by the operating pressure of the engine. The fuel pump 25 is a conventionally well-known diaphragm pump composed of a pump diaphragm 26 and a pair of check valves 27 and 28. The fuel pump 25 applies a working pressure of the engine to a pressure chamber 29 formed on one side of the pump diaphragm 26. By virtue of this, the pump diaphragm 26 is vibrated, and fuel is sucked from the fuel tank 19 through one check valve 27 into the pump chamber 30 formed on the other side of the pump diaphragm 26, and the other check valve. From 28, it is pressure-fed to the fuel chamber 6 through the fuel passage 31. When the oil surface of the fuel chamber 6 reaches the height of the plate upper surface, the fuel of the fuel chamber 6 overflows from the overflow hole 23 to form a constant oil surface.

A priming pump 33 that can be manually pressed is provided on the outer surface of the carburetor 1, and a pump chamber 34 of the pump is connected to a pump chamber 30 of the fuel pump 25. Therefore, when the priming pump 33 is repeatedly pressed, the fuel in the fuel tank 19 is supplied to the fuel chamber 6 in cooperation with the check valves 27 and 28 of the fuel pump 25.

The operation of the above embodiment will be described below. According to the above configuration, the upper surface of the plate 22 is filled with the fuel in the fuel chamber 6, and the excessively supplied fuel overflows from the gap between the overflow hole 23 provided on the upper surface of the plate 22 and the main nozzle boss 7. The overflowed fuel flows above the plate 22 and is discharged to the return passage 15 and returned to the fuel tank 19. As a result, during the operation of the engine, the fuel chamber 6 is constantly filled with fuel, and even if the circulation type carburetor 1 is tilted, air does not flow into the fuel chamber 6 from the overflow hole 23. The fuel storage amount in the fuel chamber 6 hardly changes, and the fluctuation of the oil level is suppressed. Therefore, the amount of fuel supplied to the engine hardly changes even when the vehicle is leaning, and rotational fluctuations due to the engine attitude are reduced.

[0014]

[Effect of device]

 As described above in detail, according to the present invention, a plate whose upper surface is formed at the oil level is provided in the fuel chamber, an overflow hole is provided in the upper surface of the plate, and the main nozzle boss is provided in the overflow hole. Since the fuel is allowed to overflow from the gap between the main nozzle boss and the overflow hole, only the fuel is filled in the fuel chamber, and air does not flow into the chamber even at the time of inclination, and The decline is suppressed. Therefore, the amount of fuel supplied to the engine hardly changes even when the vehicle is leaning, which has the effect of reducing rotational fluctuations due to the engine attitude.

Further, if the plate is fixed by being sandwiched between the vaporizer body and the chamber case, the plate can be easily attached and the assembling workability is improved.

[Brief description of drawings]

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

FIG. 2 is an explanatory view showing a conventional circulation type vaporizer.

[Explanation of symbols]

 1 Circulating Vaporizer 2 Vaporizer Body 6 Fuel Chamber 7 Main Nozzle Boss 15 Return Passage 22 Plate 23 Overflow Hole

Claims (2)

[Scope of utility model registration request] 1. A fuel pump driven during operation of an engine supplies fuel to a fuel chamber, and when the oil level in the chamber reaches a predetermined height, the fuel overflows to form a constant oil level, and the chamber further comprises In a fuel circulation type carburetor designed to return the fuel overflowing from the fuel tank to the fuel tank through the return passage, a plate whose upper surface is at the oil level is provided in the fuel chamber, and an overflow hole is formed on the upper surface of the plate. A circulation type carburetor, characterized in that it is provided, and a main nozzle boss is inserted into the overflow hole to allow fuel to overflow from a gap between the main nozzle boss and the overflow hole. 2. The circulation type vaporizer according to claim 1, wherein the plate has a peripheral edge sandwiched and fixed by a vaporizer body and a chamber case.