JP2003148251A - Double-barrel carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-barrel carburetor capable of simplifying the configuration of a fuel passage to reduce mechanical machining, reducing costs, and preventing the occurrence of dieseling when an engine stops. SOLUTION: A carburetor body 1 having a pair of parallel right and left suction passages 2 and a fixed fuel chamber 30 are integrally constituted. One high speed fuel passage 67 and one low speed fuel passage 54 are provided in a wall part between the pair of suction passages 2 from a central part of the fixed fuel chamber 30 via a high speed fuel jet 74. The high speed fuel passage 67 is branched into two passages on the lower face of the carburetor body 1 and is communicated with a high speed fuel injection hole 5 in the venturi part 2a of each suction passage 2 on the right and left sides. The low speed fuel passage 54 is extended to the vicinity of the upper end of the carburetor body 1 via the wall part between the suction passages 2, is branched into two branch passages 51 via a low speed fuel jet 54a on the halfway of the low speed fuel passage 54, and is communicated with a low speed fuel injection hole 6 in the vicinity of the close position of a throttle valve 9a of each suction passage 2 on the right and left sides. A solenoid opening and closing valve 41 opening and closing the high speed fuel jet 74 is provided in the lower part of the fixed fuel chamber 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a carburetor main body having a pair of left and right intake passages having a bench lily portion arranged in parallel.
The present invention relates to a twin-barreled carburetor that uniformly supplies an air-fuel mixture to each cylinder of a cylinder internal combustion engine.

[0002]

2. Description of the Related Art A twin-barreled carburetor disclosed in the publicly known Japanese Patent Laid-Open No. 10-184458 is provided with a high-speed fuel passage and a low-speed fuel passage in each intake passage. The amount is large and it is difficult to reduce costs. In addition, JP 2000-2
The twin-barreled carburetor disclosed in 05047 supplies fuel to the left and right intake passages through a common high-speed fuel jet and fuel passage, but separates the carburetor body from the lower portion of the carburetor body. Since it has a constant fuel chamber, it requires separate die-casting dies for the carburetor body and the constant fuel chamber, the passage structure is complicated, the machining amount is large, and the cost is inevitable. Is the reality.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, a main object of the present invention is to provide a twin-barreled carburetor in which a carburetor main body and a fuel tank or a constant fuel chamber are integrally formed.

[0004]

In order to solve the above-mentioned problems, the structure of the present invention has one high-speed fuel passage through a high-speed fuel jet on a wall portion between a pair of left and right intake passages provided in a carburetor main body. And one low-speed fuel passage are provided in the vertical direction, and the high-speed fuel passage branches into a pair of left and right fuel passages on the lower surface of the carburetor main body and communicates with the high-speed fuel injection holes of the bench lily portion of each intake passage. The low-speed fuel passage is a two-cylinder which is divided into a pair of left and right fuel passages through a low-speed fuel jet at the upper end of the carburetor body and communicates with the low-speed fuel injection holes near the closed positions of the throttle valves in each intake passage. In a twin-barreled carburetor for an internal combustion engine, a tubular fuel tank is integrally formed in a lower portion of a carburetor body, and a lower end of the fuel tank is sealed by a bottom plate to form a constant fuel chamber. To do.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a high-speed fuel passage and a low-speed fuel passage in which a common high-speed fuel jet and a low-speed fuel jet are arranged for a pair of left and right intake passages in a fuel passage member which is separate from the carburetor main body. And a fuel passage. The bottom plate of the constant fuel chamber is equipped with an electromagnetic on-off valve that opens and closes the lower inlet of the high-speed fuel jet. The idle fuel adjusting mechanism is formed by rotatably fitting an inverted conical idle adjusting member having a passage groove into a reverse conical hole provided in the most downstream portion of the low speed fuel passage.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, a twin-barreled carburetor according to a first embodiment of the present invention is characterized in that an air purifier is connected to an inlet end of a carburetor body 1 by four bolts 18 and vaporized. The outlet end of the carburetor body 1 is connected to an intake port for guiding the air-fuel mixture to the cylinder via a heat insulating pipe, and a pair of left and right intake passages 2 penetrate the carburetor body 1 in the front-rear direction, A chioke valve 4a is supported by the common valve shaft 4 on the inlet side of the intake passage 2, and a throttle valve 9a is supported on the outlet side of the intake passage 2 by a common valve shaft 9 to adjust the intake flow rate. There is. A lever 19 is provided at the outer end of the valve shaft 4, and the lever 19 is provided.
Is opened and closed by the rotation of the lever 19, and the valve shaft 4 is rotationally biased in the opening direction of the chain yoke valve 4a by the force of the spring 28. When the chain yoke valve 4a is closed by the lever 19 at the time of starting the engine, the chain yoke valve 4a contacts the projecting wall 26 of the intake passage 2 as shown in FIG. After starting the engine,
It is configured to automatically return to the fully open position shown in FIG. 5 by the intake negative pressure of the intake passage 2 that acts on the surface of the chioke valve 4a on the other side having a larger area than the surface on one side of the valve shaft 4. When the lever 19 is returned to the fully open position, the chain yoke valve 4a contacts the stop projection 26a and is held at the fully open position.

One end of a spring 22 wound around the valve shaft 9 is locked to a projecting piece 22a protruding laterally from the carburetor body 1, and the other end of the spring 22 is locked to a lever 21. The lever 21 is coupled to the outer end of the valve shaft 9 that supports the throttle valve 9a, is urged to rotate to the closed position of the throttle valve 9a shown in FIG. 5 by the force of the spring 22, and is a stop bolt for restricting the idle position. 32 is abutted. The stop bolt 32 is screwed and supported by the projecting wall 1a protruding laterally from the carburetor body 1, and a coil spring 31 for loosening is interposed between the head of the stop bolt 32 and the projecting wall 1a. .

As shown in FIG. 5, each intake passage 2 of the carburetor main body 1 has a bench lily portion 2a, and a high-speed fuel injection hole (main fuel nozzle) 5 is projected from each bench lily portion 2a. A low-speed fuel injection hole 6 is provided near the closed position of the throttle valve 9a in each intake passage 2, and the low-speed fuel injection hole 6 communicates with the groove passage 71 via the fuel reservoir 7. As shown in FIGS. 6 and 7, a constant fuel chamber 30 is provided integrally with the carburetor main body 1 below the intake passage 2 of the carburetor main body 1, and a sealing member is provided on a lower flange 33 of the constant fuel chamber 30. 25a through the bottom plate 48 bolt 5
Fixed by 0 to form a fuel tank 25. A plunger 45, which will be described later, is accommodated inside a recess 49 formed in the central portion of the bottom plate 48, and an electromagnetic coil 47 is arranged on the outer peripheral portion of the recess 49. The outside of the electromagnetic coil 47 is covered (overmolded) with a synthetic resin to protect the coil.

A fuel inlet pipe 16 is provided on the upper wall of the carburetor main body 1, and the fuel inlet pipe 16 is connected to a fuel inflow passage 55 extending upward from the lower portion of the carburetor main body 1. A valve housing 56 is fitted in a large-diameter cylindrical portion at the lower end of the fuel inflow passage 55, and an inflow valve 57 having an axial groove on the outer peripheral surface is housed in the valve housing 56. The lower end of the inflow valve 57 is the constant fuel chamber 3
A pair of left and right floats 65 accommodated in the constant fuel chamber 30 are attached to the ends of the arms 60 that are rotatably supported by the support shaft 58 on the wall portion of 0. Constant fuel chamber 30
When the oil level becomes low, the arm 60 rotates in the counterclockwise direction around the support shaft 58 together with the float 65, and the inflow valve 57 also descends to open the lower part of the fuel inflow passage 55 to transfer the fuel to the constant fuel chamber 30. refill. When the oil level in the constant fuel chamber 30 reaches a predetermined position, the inflow valve 57 as well as the float 65 rises to close the lower end of the fuel inflow passage 55.

A metal or synthetic resin fuel passage member 61 attached to the lower portion of the carburetor main body 1 via a seal member 59 has a T-shaped overall shape, and a T-shaped high-speed fuel passage 67 in the front. However, the low speed fuel passages 54 in the vertical direction are formed in the column portion 61a at the rear, respectively, and both communicate at the lowermost portion. A high speed fuel jet 74 is disposed at the lowermost portion of the passages 67 and 54, an annular groove on the outer periphery of the high speed fuel jet 74 is engaged with the lowermost annular protrusion 66 of the fuel passage member 61, and the high speed fuel jet 74 is also provided. Bottom flange 75 of
A seal member 76 is disposed between the fuel passage member 61 and the fuel passage member 61. The four guide leg pieces 63 integrated with the fuel passage member 61 are
It is fitted into a recess 49 provided in the central portion of the bottom plate 48 of the constant fuel chamber 30. The plunger 45 is accommodated in an empty portion of the fuel passage member 61 surrounded by the four guide leg pieces 63.
The conical upper end of the plunger 45 has a high-speed fuel jet 7.
The lower end surface of 4 functions as a valve body having a valve seat. A spring 46 arranged between the intermediate step portion of the plunger 45 and the recess 49.
Force causes the upper end of the plunger 45 to close the high speed fuel jet 74. Plunger 45 and bottom plate 48 recess 4
The electromagnetic coil 47 fixed to the outer peripheral portion of 9 constitutes an electromagnetic opening / closing valve 41.

An air passage 14 for taking in air from the air purifier is provided near the center of the intake passage 2 of the carburetor body 1 on the inlet side, and a high-speed air jet 17 is arranged in the back of the air passage 14. The air passage 14 is connected to the air passage 62 extending in the vertical direction behind the high-speed air jet 17.
An emulsification tube 64 having a large number of through holes is fitted into the enlarged lowermost portion of the air passage 62. Emulsion tube 6
4 extends to the high speed fuel passage 67 of the fuel passage member 61. A high-speed fuel injection hole 5 is projected from the end of the upper horizontal portion 67a of the high-speed fuel passage 67 to the bench lily portion 2a of the intake passage 2. The porous member 34 is fitted in the upper horizontal portion of the high-speed fuel injection hole 5, and the end of the upper horizontal portion 67 a of the high-speed fuel passage 67 is closed by the ball 35.

The low-speed fuel passage 54 of the fuel passage member 61 is connected to the low-speed fuel passage 53 of the carburetor body 1, and the low-speed fuel jet 5 is provided in an enlarged portion above the low-speed fuel passage 53.
4a is inserted. As shown in FIG. 8, the low-speed fuel passage 5
3, the upper end of which is closed by a gasket 15a, is connected to a branch passage 51 that is divided obliquely upward and leftward from the middle. As shown in FIG. 9, a low speed air jet 36 is arranged in the inner part of the pair of left and right air passages 14 a, and the branch passage 51 and the groove passage 71 join together. A porous member 52 such as a wire mesh or a sintered material is fitted into the branch passage 51. The porous member 52 acts like a check valve due to the surface tension of the attached fuel. That is, the fuel flows from the branch passage 51 to the groove passage 71, but conversely the fuel flows from the groove passage 71 to the branch passage 51.
It is prevented by the surface tension of the fuel with which the porous member 52 is impregnated.

As shown in FIG. 2, on the upper wall of the carburetor main body 1, two V-shaped gaskets 15a sandwiching the fuel inlet pipe 16 and a cover plate 15 are provided so as to cover the groove passage 71 of the upper wall. It is fixed by the bolt 12 of. As shown in FIG.
An idle fuel adjusting mechanism 69 is provided in the groove passage 71 connected to the branch passage 51. The adjusting mechanism 69 has a groove passage 71.
It is composed of an inverted cone-shaped idle adjusting member 70 that is rotatably housed in an inverted cone-shaped hole provided at the back of the. A fuel reservoir 7 is provided below the idle adjusting member 70, and a low-speed fuel injection hole 6 communicating with the intake passage 2 is provided at the bottom of the fuel reservoir 7. The low-speed fuel injection hole 6 is disposed upstream of the fully closed position of the throttle valve 9a in the intake passage 2, and the idle fuel injection hole 68 is provided downstream of the fully closed position of the throttle valve 9a in the intake passage 2. It is provided. The idle adjusting member 70 has a cylindrical upper half shaft portion 77 having a notch 78 and a lower half cone portion, and the boundary between them is a step portion 79, and a split groove is formed on the bottom surface of the upper half shaft portion 77. 77a is provided.

A hole 1 having the same diameter as the outer diameter of the upper half shaft portion 77 of the idle adjusting member 70 is formed in the cover plate 15 and the gasket 15a.
3, the claw 20 protruding from the inner peripheral edge of the hole 13 is
The idle adjusting member 70 engages with the notch 78 of the upper half shaft portion 77, and as shown by the arrow in FIG.
Regulates the rotation range of. The edge of the hole 13 of the cover plate 15 presses the step 79 of the idle adjusting member 70 to prevent the idle adjusting member 70 from falling off. The T-shaped axial groove 72 and the oblique groove 7 are formed on the outer peripheral surface of the lower half-cone portion of the idle adjusting member 70.
3, the upper end of the axial groove 72 communicates with the groove passage 71, and the intermediate portion of the oblique groove 73 communicates with the starting end of the idle fuel injection hole 68. The lower ends of the axial groove 72 and the oblique groove 73 communicate with the fuel reservoir 7. The idle fuel adjustment by the adjusting mechanism 69 is performed by engaging the tip of the driver with the split groove 77a of the upper half shaft portion 77 of the idle adjusting member 70 and rotating the same.
That is, as shown in FIG. 13, the opening area is changed by the change of the intersecting position of the oblique groove 73 of the idle adjusting member 70 with respect to the opening of the idle fuel injection hole 68, and the fuel injection amount is adjusted.

Next, the operation of the twin-barreled vaporizer according to the first embodiment of the present invention will be described. When operating the engine,
The lever 19 is rotated clockwise in FIG. 3 to the closed position where the chain yoke valve 4a comes into contact with the projecting wall 26, and the electromagnetic coil 4
7 is energized to pull down the plunger 45 against the force of the spring 46, the upper end of the plunger 45 separates from the high speed fuel jet 74, and the fuel in the constant fuel chamber 30 flows into the high speed fuel jet 74.

In the low-speed fuel system, the fuel from the high-speed fuel jet 74 passes through the low-speed fuel passage 54, the low-speed fuel jet 54a, the low-speed fuel passage 53, the branch passage 51, the groove passage 71, and the low-speed air jet 36 of the air passage 14a. From the axial groove 72 of the idle adjustment member 70,
It is supplied to the intake passage 2 through the fuel reservoir 7 and the low-speed fuel injection hole 6. On the other hand, a part of the fuel in the fuel reservoir 7 is part of the idle adjusting member 7.
It is supplied to the intake passage 2 through the oblique groove 73 located at the rear of 0 and the idle fuel injection hole 68.

Now, when negative suction pressure acts on the right intake passage 2 in the intake stroke of the right cylinder, the fuel is in an emulsion state mixed with air, and passes through the low speed fuel injection hole 6 on the right side through the intake passage 2. Supplied to the right cylinder. At this time,
Since the intake negative pressure is not acting on the low speed fuel system on the left side,
The intake negative pressure does not act on the porous member 52 of the left branch passage 51, and the fuel and the air do not flow backward from the left intake passage 2 due to the surface tension of the fuel impregnated in the porous member 52. . Next, when the left cylinder enters the intake stroke and negative intake pressure acts on the left intake passage 2, this time, the fuel is mixed with air and is in an emulsion state. It is supplied to the left cylinder via 2 At this time, since the intake negative pressure does not act on the right low-speed fuel system, the intake negative pressure does not act on the porous member 52 of the right branch passage 51, and the surface of the fuel impregnated in the porous member 52 is not affected. Due to the action of tension, the fuel and the air do not flow backward from the intake passage 2 on the right side. Thus, the fuel is accurately supplied to each cylinder.

In the high-speed fuel system, the fuel from the high-speed fuel jet 74 flows into the high-speed fuel passage 67, and is mixed with the air sucked from the air passage 14 through the high-speed air jet 17, the air passage 62 and the emulsion pipe 64. While being supplied to the intake passage 2 through the upper horizontal portion 67 a of the high speed fuel passage 67 and the high speed fuel injection hole 5. When fuel is ejected to the intake passage 2 on the right side, the upper horizontal portion 67 on the left side of the high-speed fuel passage 67 is
The surface tension of the fuel impregnated in the porous member 34 a prevents the backflow of fuel and air from the left intake passage 2. On the contrary, when the fuel is ejected to the left intake passage 2, the surface tension of the fuel impregnated in the porous member 34 of the upper horizontal portion 67a on the right side of the high-speed fuel passage 67 causes
Backflow of fuel and air from the right intake passage 2 is prevented.

As described above, in this embodiment, as shown in FIG. 14, the fuel is supplied to each of the left and right intake passages 2 via one high speed fuel jet 74 and one low speed fuel jet 54a. is there. When the left and right high-speed fuel jets are provided separately as in the conventional carburetor, the fuel flow rate varies due to the influence of the fuel passage, but in the present embodiment, the left-right common high-speed fuel jet 74 and the low-speed fuel jet are common. By providing the jet 54a, it is possible to eliminate variations in the fuel flow rate in the left and right intake passages 2. When the electric ignition system of the engine is opened, the electromagnetic coil 47 is demagnetized, and the force of the spring 46 causes the upper end of the plunger 45 to close the valve seat which is the lower end surface of the high speed fuel jet 74. The fuel supply to the low-speed fuel passage 54 is immediately cut off, and there is no Dieseling.

In the second embodiment of the present invention shown in FIG. 15, T
A pair of left and right high-speed fuel passages 67 in the up-and-down direction are provided in the pillar portion 61a of the character-shaped fuel passage member 61.
The emulsion tube 64 is inserted into the. A pair of elastic leg pieces 80 are provided in the vicinity of the lower portion of the column portion 61a, and the elastic leg pieces 8
By bringing 0 into contact with the upper surface of the bottom plate 48 of the constant fuel chamber 30, the elastic reaction force of the elastic leg pieces 80 causes the fuel passage member 61 to move.
Are pressed against the vaporizer body 1. A seal member 61 is provided between the upper surface of the T-shaped fuel passage member 61 and the carburetor body 1.
Insert b. The porous member 34 disposed near the inlet of the high-speed fuel injection hole 5 in the upper horizontal portion 67a of the high-speed fuel passage 67.
Are tilted at an angle to reduce flow resistance.
The lowermost end of the fuel passage member 61 is a cylindrical guide leg piece 63 having a large number of slits. The other configurations are the same as those of the twin-barreled vaporizer according to the first embodiment.

Depending on the engine, the left and right intake systems and the fuel system may have different cooling characteristics and intake pipe lengths. In the case of such an engine, it is necessary to make a difference in the fuel supply amount to the left and right cylinders. In the present embodiment, the left and right independent high-speed fuel passages are provided, so the problem can be solved by adjusting the left and right balance.

[0022]

As described above, according to the present invention, the carburetor main body and the constant fuel chamber or the fuel tank are integrally formed, and the lower end of the fuel tank is sealed by the bottom plate to form the constant fuel chamber. There is no need for an expensive die-casting mold for the chamber, and since it is not necessary to make a hole or the like in the bottom plate only with a recess, fuel leakage does not occur when the bottom plate is attached.

Unlike the conventional case, it is not necessary to extend a thick fuel passage downward from the central portion of the lower surface of the carburetor main body, and there is no influence of a cavity formed by die casting of the carburetor main body and the fuel tank, so that the yield is improved, Since the thickness of the carburetor body and the fuel tank can be made uniform, the minimum necessary machining is required.

Since the electromagnetic coil overmolded with the synthetic resin is directly attached to the outer periphery of the recess of the bottom plate of the fuel tank, the cover which bends the iron plate and the thick screw for attaching this are not necessary, and the weight and cost are reduced as a whole. Help reduce.

The plunger housed in the recess of the bottom plate of the constant fuel chamber is surrounded by the guide leg pieces at the lower end of the fuel passage member, and the lower surface of the high speed fuel jet is closed by the upper end portion of the plunger, so that the electromagnetic coil and the plunger are connected. It is not necessary to consider the concentricity, and there is no problem in function even if there is some deviation in the mounting of the electromagnetic coil.

Since the fuel is supplied from the common high-speed fuel jet and the high-speed fuel passage to the left and right intake passages, the variation in the amount of fuel to the left and right intake passages can be reduced, the structure of the fuel passage can be simplified, and the electromagnetic coil Since the lower surface of the high-speed fuel jet is closed by the action, the engine is immediately stopped, and the diesel ring can be prevented.

Since the high-speed fuel injection hole is formed integrally with the fuel passage member and protrudes from the lower part of the intake passage to the bench lily portion, the high-speed fuel injection hole is arranged at the optimum position with respect to the throttle valve, and the fuel Jetting is stable, engine performance is improved, and variations in engine performance can be suppressed.

Since the reverse cone-shaped idle adjusting member is fitted in the reverse cone-shaped hole above the low-speed fuel injection hole, the performance of the low-speed fuel system is improved, the passage structure is simple, and the number of parts and the number of processings are increased. There are few, and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a twin-body vaporizer according to a first embodiment of the present invention.

FIG. 2 is a plan view of the twin-body vaporizer.

FIG. 3 is a side view of the twin-barreled vaporizer.

FIG. 4 is a plan cross-sectional view showing an open state of a chiyoke valve in the twin-barreled carburetor.

FIG. 5 is a side sectional view showing an intake passage of the twin-body vaporizer.

FIG. 6 is a side sectional view of the twin-barreled vaporizer.

FIG. 7 is a front sectional view of the twin-barrel vaporizer.

FIG. 8 is a front sectional view showing a branch passage of a low-speed fuel passage in the twin-barreled carburetor.

FIG. 9 is a plan view showing a state in which the cover plate and the gasket of the twin-barreled vaporizer are removed.

FIG. 10 is a side sectional view showing a schematic configuration of a high speed fuel system and a low speed fuel system in the vicinity of an intake passage of the twin-barreled carburetor.

FIG. 11 is a plan view showing a rotation range of an idle adjusting member in the twin-body vaporizer.

FIG. 12 is a perspective view of an idle adjusting member in the twin-body vaporizer.

FIG. 13 is a rear view of the idle adjusting member in the twin-body vaporizer.

FIG. 14 is a schematic configuration diagram of a fuel passage and an air passage in the twin-barreled carburetor.

FIG. 15 is a front sectional view of a twin-body vaporizer according to a second embodiment of the present invention.

[Explanation of symbols]

1: carburetor body 2: intake passage 5: high-speed fuel injection hole 6:
Low-speed fuel injection hole 7: Fuel reservoir 8: Throttle valve lever 13:
Hole 14: Air passage 15: Cover plate 16: Fuel inlet pipe 17: High-speed air jet 20: Claw 25: Fuel tank 26: Projection wall 30: Constant fuel chamber 32: Stop bolt 3
3: Lower flange 34: Porous member 36: Low speed air jet 41: Electromagnetic on-off valve 45: Plunger 4
7: Electromagnetic coil 48: Bottom plate 49: Recess 51: Branch passage 52: Porous member 53: Low-speed fuel passage 5
4: Low speed fuel passage 55: Fuel inflow passage 56: Valve housing 57: Inflow valve 60: Arm 61: Fuel passage member
62: air passage 63: guide leg piece 64: emulsion tube 65: float 67: high-speed fuel passage 68: idle fuel injection hole 69: adjusting mechanism 70: idle adjusting member 71: groove passage 72: axial groove 73: oblique groove 7
4: High speed fuel jet 75: Flange 77: Upper half shaft 78: Notch 79: Step 80: Elastic leg piece

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) F02M 7/20 F02M 7/20 D 17/40 17/40 A

Claims (9)

[Claims] 1. A high speed fuel passage and a low speed fuel passage are vertically provided on a wall portion between a pair of left and right intake passages provided in a carburetor body through a high speed fuel jet. Is branched into a pair of left and right fuel passages on the lower surface of the carburetor body and communicates with the high-speed fuel injection holes of the bench lily portion of each intake passage, and the low-speed fuel passage has a low-speed fuel jet at the upper end of the carburetor body. In a twin-barreled carburetor for a two-cylinder internal combustion engine, which branches into a pair of left and right fuel passages and communicates individually with low-speed fuel injection holes near the closed position of the throttle valve of each intake passage, A twin-barreled vaporizer characterized in that a tubular fuel tank is integrally formed, and a lower end of the fuel tank is sealed by a bottom plate to form a constant fuel chamber. 2. The high-speed fuel passage and the low-speed fuel passage are formed in a T-shaped fuel passage member that is separate from the carburetor body, and the passage in the upper horizontal portion of the fuel passage member that extends below each intake passage. The double-hulled carburetor according to claim 1, wherein an end portion of the fuel tank communicates with the high-speed fuel injection hole. 3. The twin-barreled carburetor according to claim 2, wherein the fuel passage member is made of synthetic resin. 4. An elastic leg piece abutting against the bottom plate is provided at a lower end of the fuel passage member, and the fuel passage member is pressed against the lower surface of the carburetor main body by a reaction force of the elastic leg piece.
The twin-body vaporizer described in 1. 5. An electromagnetic coil of an electromagnetic on-off valve protected by a resin mold is fixed to the bottom plate made of a magnetic material, and is integrated with a plunger that receives the force of a spring when the electromagnetic coil is demagnetized by opening the electric ignition system. The twin-barreled carburetor of claim 1, wherein a valve body closes a fuel passage of the high speed fuel jet. 6. The twin-body carburetor according to claim 5, wherein a guide leg piece for guiding the vertical movement of the plunger is provided at the lower end of the fuel passage member. 7. The twin cylinder vaporizer according to claim 1, wherein the low-speed fuel passage communicates with the left and right branch passages having a porous member through the low-speed fuel jet. 8. An inverted conical hole and a fuel reservoir are provided between the low speed fuel passage and the low speed fuel injection hole and the idle fuel injection hole, and the lower half of the idle adjusting member is provided in the inverted conical hole. The conical portion is rotatably fitted and the opening area of the base end of the idle fuel injection hole and the axial groove that connects the low speed fuel passage and the fuel reservoir to the peripheral surface of the lower half conical portion is adjusted. The twin-barreled vaporizer according to any one of claims 1 to 7, further comprising an oblique groove. 9. The idle adjusting member has an upper half-cylindrical portion fitted into a hole of a cover plate which is superposed and coupled to the upper surface of the carburetor main body, and has a hole from the cover plate to an intermediate step portion of the idle adjusting member. 9. The twin-barreled carburetor of claim 8 engaged with a projecting claw.