JP2004293360A - Mixture supply device - Google Patents

Abstract

An object of the present invention is to improve the waterproofness and dustproofness of an air-fuel mixture supply device with respect to a vaporizer, and to reduce the cost of the air-fuel mixture supply device.
An air-fuel mixture supply device having an air cleaner box is attached to an engine. The air cleaner box 28 includes an input side intake pipe 29 communicating with the outside and an output side intake pipe 30 communicating with the combustion chamber 15a of the engine 25. The air cleaner box 28 defines a dust chamber 31a and a clean chamber 31b. The air filter 31 is accommodated. Further, the vaporizer 32 for feeding the air-fuel mixture into the combustion chamber 15a is accommodated in a clean chamber 31b of the air cleaner box 28. Since the vaporizer 32 is not exposed to water or dust and can increase the waterproofness and dustproofness of the vaporizer 32, the waterproof structure and dustproof structure of the vaporizer 32 can be simplified, and Cost reduction of the supply device 27 can be achieved.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air-fuel mixture supply device for supplying an air-fuel mixture to an engine.
[0002]
[Prior art]
When supplying fuel to the engine, the fuel is sucked out by the negative pressure in the intake pipe and atomized, and a carburetor or carburetor that supplies it to the engine is injected into the intake pipe and combustion chamber according to the amount of intake air. Injection valves, ie, injectors, are used.
[0003]
In order to control the air-fuel ratio of the air-fuel mixture supplied to the engine with high accuracy, an injector is more preferable than a carburetor, but the injector is not only a fuel system component that pressurizes and injects fuel, but also an intake air amount. Therefore, the use of an injector is accompanied by an increase in cost, since an air-based component for detecting the pressure and a control system component for correcting the injection amount and performing feedback control are required.
[0004]
On the other hand, the carburetor can feed fuel to the engine according to the amount of intake air by the negative pressure that changes with the increase of the air flow velocity, not only does not cause the control system to become complicated, but also reduces the number of parts. Since the number is small, cost reduction can be achieved. For this reason, carburetors are often used mainly for inexpensive small engines mounted on all terrain vehicles such as ATVs (All Terrain Vehicles), motorcycles, and generators.
[0005]
When such a carburetor is mounted on a vehicle, the carburetor is arranged between the engine and the air cleaner box. An intake duct communicating with the air cleaner box is attached to the input port of the carburetor, and an intake pipe communicating with the intake port of the engine is attached to the output port (for example, see Patent Document 1).
[0006]
[Patent Document 1]
JP-A-11-11171 (pages 3-4, FIGS. 1 and 4)
[0007]
[Problems to be solved by the invention]
However, when the carburetor is placed between the engine and the air cleaner box, that is, when the carburetor is mounted on a vehicle with the carburetor exposed outside, it is necessary to protect the carburetor from splashing water and mud splashing. High waterproof and dustproof properties are required. In particular, in the case of carburetors in which levers for opening and closing the throttle valve are provided on the outside, the sliding part is housed in a separate case to increase the waterproof and dustproof properties of the sliding part exposed to the outside. And the cost of the carburetor must be increased.
[0008]
An object of the present invention is to achieve cost reduction of an air-fuel mixture supply device with improved waterproofness and dustproofness for a vaporizer.
[0009]
[Means for Solving the Problems]
An air-fuel mixture supply device of the present invention is an air-fuel mixture supply device that supplies air-fuel mixture to a combustion chamber of an engine, and includes an input-side intake pipe communicating with the outside, and an output-side intake pipe communicating with the combustion chamber of the engine. An air cleaner box comprising: an air filter box that is housed in the air cleaner box and partitions the inside of the air cleaner box into an input-side dust chamber and an output-side clean room; and an air filter that is housed in a clean room of the air cleaner box. And a carburetor that mixes fuel with the air and sends it to the output-side intake pipe.
[0010]
The air-fuel mixture supply device according to the present invention is characterized in that a throttle cable for operating the carburetor is drawn into the air cleaner box from the input side intake pipe.
[0011]
According to the present invention, since the vaporizer is housed in the clean room of the air cleaner box, the vaporizer is not exposed to water or dust, and the waterproofness and dustproofness of the vaporizer can be dramatically improved. Can be.
[0012]
Thereby, the waterproof structure and the dust-proof structure provided in the vaporizer can be simplified, and the cost of the air-fuel mixture supply device can be reduced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a vehicle. The vehicle is an ATV, which is also called a buggy vehicle, that is, an all-terrain vehicle. As shown in FIG. 1, a vehicle body 1 is provided with front wheels 2a, 2b and rear wheels 3a, 3b, and a saddle type seat 4 is provided in the center of the vehicle body 1. The occupant gets into the vehicle across the seat 4 and operates by operating the steering wheel 5.
[0014]
FIG. 2 is a schematic view showing the engine unit 10 and the drive unit 11 mounted on the vehicle in FIG. 1, and FIG. 3 is a cross-sectional view along the line AA in FIG. As shown in FIGS. 2 and 3, an engine unit 10 for outputting engine power is provided on the front side of the vehicle, and a drive unit 11 for transmitting the engine power to driving wheels is provided on the rear side of the vehicle. .
[0015]
As shown in FIG. 2, a crankshaft 13 is rotatably housed in a crankcase 12 of the engine unit 10 via a bearing. As shown in FIG. 3, a cylinder 14 is attached to an opening formed above the crankcase 12, and a cylinder head 15 is mounted on an upper end surface of the cylinder 14. A piston 16 is incorporated in a cylinder bore formed in the cylinder 14 so as to be able to reciprocate. A piston pin 17 attached to the piston 16 and a crank pin 18 eccentrically fixed to the crankshaft 13 from the rotation center thereof are described below. , Connecting rods 19.
[0016]
A combustion chamber 15a is formed in the cylinder head 15, and an intake port 15b and an exhaust port 15c that open to the combustion chamber 15a are formed. An intake valve 20 for switching the intake port 15b and the combustion chamber 15a between a communicating state and a shutoff state is incorporated in the cylinder head 15, and an exhaust valve for switching the exhaust port 15c and the combustion chamber 15a between a communicating state and a shutoff state. 21 is incorporated in the cylinder head 15.
[0017]
A camshaft 22 having two cam surfaces is rotatably mounted on the cylinder head 15, and a rocker shaft 23 provided in parallel with the camshaft 22 has a rocker arm 23 a for opening and closing the intake valve 20, A rocker arm 23b for opening and closing the exhaust valve 21 is rotatably mounted. A timing chain (not shown) is bridged between a sprocket (not shown) fixed to the camshaft 22 and a sprocket 24 fixed to the end of the crankshaft 13 as shown in FIG. The rotation is driven in synchronization with the rotation of the crankshaft 13. The camshaft 22 contacts the cam surface with one end of the rocker arms 23a and 23b in accordance with the rotation position of the crankshaft 13, that is, the movement position of the piston 16, so that each of the intake valve 20 and the exhaust valve 21 is opened and closed at a predetermined timing. Is done.
[0018]
The engine 25 including the crankcase 12, the cylinder 14, and the cylinder head 15 is mounted on the vehicle body 1 such that the crankshaft 13 faces the vehicle width direction. The engine 25 is a single-cylinder air-cooled engine, and radiation fins 26 are formed on the cylinder 14 and the cylinder head 15.
[0019]
In order to supply an air-fuel mixture to the engine 25, an air-fuel mixture supply device 27 according to an embodiment of the present invention is arranged behind the engine 25 on the vehicle side. The air-fuel mixture supply device 27 includes a hollow air cleaner box 28, and an input-side intake pipe 29 communicating with the outside and an output-side intake pipe 30 communicating with the intake port 15b of the engine 25 are attached to the air cleaner box 28. ing. Further, an air filter 31 for removing dust in the intake air is incorporated in the air cleaner box 28. The air cleaner box 28 includes a dust chamber 31a in which the input side intake pipe 29 is opened by the air filter 31 and an output side intake pipe. 30 is divided into a clean room 31b that opens.
[0020]
The clean room 31b of the air cleaner box 28 contains a vaporizer 32 for mixing fuel with air from which dust has been removed. The carburetor 32 has a carburetor body 33 in which an input port 33a and an output port 33b are formed coaxially. The input port 33a opens into the clean chamber 31b, while the output port 33b is connected to the output side intake pipe 30. Connected to. A venturi section 33c is formed between the input port 33a and the output port 33b of the carburetor body 33, and a vacuum piston 34 for opening and closing the venturi section 33c is mounted on the carburetor body 33 in a reciprocating manner. . The vacuum piston 34 is provided with a diaphragm 35 which defines a negative pressure chamber 33d above the carburetor body 33. The negative pressure chamber 33d communicates with the output side intake pipe 30 via a negative pressure hose (not shown). I do. A compression coil spring 36 is incorporated in the negative pressure chamber 33d, and the vacuum piston 34 is pushed down by the compression coil spring 36 in a direction of blocking the venturi portion 33c.
[0021]
The output port 33b of the carburetor body 33 is provided with a throttle valve 37 for opening and closing the output port 33b. A rotary shaft 37a to which the throttle valve 37 is fixed is rotatably supported by the carburetor body 33. I have. The rotating shaft 37a is provided so as to protrude outside the carburetor main body 33, and a throttle lever 38 is attached to an end of the protruding rotating shaft 37a. One end of a throttle cable 39 is attached to the throttle lever 38, and the other end of the throttle cable 39 is guided from the input side intake pipe 29 to the outside of the air cleaner box 28, and is attached to the accelerator grip 6 shown in FIG. In other words, since the throttle lever 38 and the accelerator grip 6 are connected via the throttle cable 39, the throttle valve 37 is opened and closed by the operation of the accelerator grip 6 by the occupant. A fuel hose (not shown) for guiding fuel from the fuel tank 7 shown in FIG. 1 is connected to the carburetor body 33, and the fuel is guided to the float chamber 33e opened to the venturi section 33c via jets. .
[0022]
When the occupant operates the accelerator grip 6 to open the output port 33b, the flow velocity in the output side intake pipe 30 increases, so that a negative pressure is generated in the negative pressure chamber 33d communicating with the output side intake pipe 30. As a result, the vacuum piston 34 is pushed up toward the negative pressure chamber 33d against the spring force, so that the venturi portion 33c is gradually opened. When the carburetor 32 operates in this manner, the air flowing from the input port 33a toward the output port 33b increases, so that a negative pressure is generated in the venturi section 33c by the air flowing through the venturi section 33c. Thus, the fuel in the float chamber 33e is drawn into the venturi section 33c. In the venturi section 33c into which the air flows, the fuel and the air are mixed to form an air-fuel mixture, and the air-fuel mixture output from the output port 33b is guided to the intake port 15b of the cylinder head 15 via the output-side intake pipe 30. You. When the output port 33b is shut off by operating the accelerator grip 6, the flow velocity in the output-side intake pipe 30 decreases, so that the vacuum piston 34 is pushed down by the spring force.
[0023]
The air-fuel mixture guided to the intake port 15b is sent into the combustion chamber 15a during an intake stroke in which the intake valve 20 is driven to open, and is converted into engine power by burning through a compression stroke and a combustion stroke. The burned air-fuel mixture becomes exhaust gas and is discharged to the outside from an exhaust port 15c via an exhaust pipe (not shown) during an exhaust stroke. The piston 16 depressed by the combustion of the air-fuel mixture drives the crankshaft 13 via a connecting rod 19 to output engine power to a drive unit 11 described later.
[0024]
As shown in FIG. 3, two balancer shafts 40 and 41 are rotatably mounted on the crankcase 12 via bearings, and the balancer shafts 40 and 41 are integrally provided with balancer weights 40a and 41a. Is provided. The gears 40b and 41b provided on the balancer shafts 40 and 41 mesh with the gears 42 provided on the crankshaft 13, and rotation fluctuations of the crankshaft 13 are absorbed by the balancer weights 40a and 41a. FIG. 2 shows one balancer shaft 40 of the two balancer shafts.
[0025]
An oil pump 43 driven by the crankshaft 13 is provided at one end of the crankshaft 13, and lubricating oil discharged from the oil pump 43 is supplied to a sliding portion of the drive unit 11 via an oil passage (not shown). Is done. A power generator 44 driven by the crankshaft 13 is provided at the other end of the crankshaft 13, and the power generated by the power generator 44 is charged into a battery (not shown). Further, a starter motor 45 is provided adjacent to the power generator 44, and the rotation of the starter motor 45 driven when the engine 25 starts is transmitted to the crankshaft 13 via gears 46a and 46b.
[0026]
As shown in FIG. 2, a sub shaft 47 is mounted on the crankcase 12 so as to be rotatable in parallel with the crankshaft 13. The gear 48a provided on the sub shaft 47 meshes with the gear 48b provided on the crank shaft 13, and the rotation of the crank shaft 13 is transmitted to the sub shaft 47. A recoil cover 49 is attached to the crankcase 12 at one end of the countershaft 47. When the battery 25 has a shortage of charge and it is difficult to start the engine 25, the engine 25 is manually operated. A recoil starter 50 to be started is mounted. The recoil starter 50 includes a recoil pulley 50b housed in the recoil cover 49 and around which the recoil rope 50a is wound, and a recoil drum 50c attached to the counter shaft 47. By rotating, the engine 25 can be started by rotating the crankshaft 13 via the sub shaft 47.
[0027]
A centrifugal clutch 51 is attached to the other end of the sub shaft 47. The centrifugal clutch 51 includes a clutch drum 51a rotatably mounted in the crankcase 12, and a rotating plate 51b fixed to the sub shaft 47. And A plurality of arc-shaped clutch shoes 51c are attached to the rotating plate 51b, and each clutch shoe 51c is rotatable by a pin 51d attached to one end. A tension coil spring 51e is attached to the other end of the clutch shoe 51c, and a spring force is applied to the clutch shoe 51c in a direction away from the inner peripheral surface of the clutch drum 51a. Therefore, when the counter shaft 47 exceeds a predetermined number of revolutions, the centrifugal force applied to the clutch shoe 51c exceeds the spring force, so that the clutch shoe 51c engages with the inner peripheral surface of the clutch drum 51a and the centrifugal clutch 51 is engaged. In this state, the engine power from the crankshaft 13 is transmitted to the clutch drum 51a via the sub shaft 47.
[0028]
A primary shaft 52 is fixed to the clutch drum 51a, and the primary shaft 52 is rotatably accommodated in a transmission case 53 assembled to the crankcase 12. A secondary shaft 54 is rotatably accommodated in the transmission case 53 in parallel with the primary shaft 52, and a continuously variable transmission 55 for transmitting the engine power from the primary shaft 52 to the secondary shaft 54 is provided. It is mounted in the transmission case 53.
[0029]
The continuously variable transmission 55, that is, the CVT is a belt-type continuously variable transmission 55. The continuously variable transmission 55 includes a primary pulley 56 provided on the primary shaft 52 and a secondary pulley 57 provided on the secondary shaft 54. I have. The primary pulley 56 includes a fixed sheave 56a having a conical surface and a movable sheave 56b having a conical surface facing the fixed sheave 56a. The fixed sheave 56a is fixed to the primary shaft 52, and the movable sheave Reference numeral 56b is attached to a spline provided on the primary shaft 52 so as to be movable in the axial direction. On the other hand, the secondary pulley 57 includes a fixed sheave 57a having a conical surface and a movable sheave 57b having a conical surface facing the fixed sheave 57a. The fixed sheave 57a is fixed to the secondary shaft 54, The movable sheave 57b is mounted on a spline provided on the secondary shaft 54 so as to be movable in the axial direction.
[0030]
A rubber V-belt 60 is stretched between the primary pulley 56 and the secondary pulley 57. When the winding diameter of the V-belt 60 around the primary pulley 56 and the secondary pulley 57 changes, the rotation of the primary shaft 52 changes. Is transmitted to the secondary shaft 54 with the gear ratio changing steplessly. The movable sheave 56b of the primary pulley 56 is provided with a plurality of, for example, six, cylindrical centrifugal weights 61 oriented in a direction perpendicular to the rotation center of the primary shaft 52. A cam surface 62 corresponding to the centrifugal weight 61 is formed on the movable sheave 56b, and the cam surface 62 has a shape such that a radially outer portion of the movable sheave 56b protrudes toward an end of the primary shaft 52. . A cam plate 63 is fixed to the primary shaft 52 so as to face the cam surface 62, and a radially outer portion of the cam plate 63 is inclined so as to approach the cam surface 62. On the other hand, a spring support 64 is fixed to the secondary shaft 54, and a compression coil spring 65 for applying a tightening force to the V-belt 60 is mounted between the spring support 64 and the movable sheave 57b.
[0031]
When the rotation speed of the primary shaft 52 increases, the centrifugal force applied to the centrifugal weight 61 increases. Therefore, the centrifugal weight 61 moves radially outward while pushing between the movable sheave 56b and the cam plate 63. Here, since the cam plate 63 is fixed to the primary shaft 52, the movement of the centrifugal weight 61 causes the movable sheave 56b to approach the fixed sheave 56a. As a result, the groove width of the primary pulley 56 is reduced and the winding diameter of the V belt 60 around the primary pulley 56 is increased, while the groove width of the secondary pulley 57 is expanded by the V belt 60 against the spring force. The winding diameter of the belt 60 around the secondary pulley 57 is reduced. That is, the higher the rotation speed of the primary shaft 52, the higher the speed ratio of the continuously variable transmission 55 changes.
[0032]
When the rotation speed of the primary shaft 52 decreases and the centrifugal force applied to the centrifugal weight 61 decreases, the groove width of the secondary pulley 57 is reduced by the spring force applied to the secondary pulley 57. The winding diameter of the primary pulley 56 is increased by the V-belt 60 while the winding diameter of the V-belt 60 is increased, so that the winding diameter of the V-belt 60 around the primary pulley 56 is reduced. That is, the speed ratio of the continuously variable transmission 55 changes to the lower speed side as the rotation speed of the primary shaft 52 decreases.
[0033]
One end of the secondary shaft 54 protrudes from the transmission case 53 and is supported via a bearing on a gear case 66 assembled to the transmission case 53. An output shaft 67 is rotatably accommodated in the gear case 66 in parallel with the secondary shaft 54, and an axle 68 is rotatably mounted in parallel with the output shaft 67.
[0034]
A forward gear 69a is provided integrally with the secondary shaft 54, and the gear 69a is always engaged with a gear 69b rotatably mounted on the output shaft 67. Further, a reciprocating sprocket 70a is integrally provided on the secondary shaft 54, and a chain 70c is stretched between the sprocket 70a and a sprocket 70b rotatably mounted on the output shaft 67. In other words, the rotation direction of the gear 69b driven by the power from the secondary shaft 54 is opposite to the rotation direction of the secondary shaft 54, and the rotation direction of the chain driven sprocket 70b is the same as the rotation direction of the secondary shaft 54. become.
[0035]
A forward / reverse switching mechanism 71 is mounted between the gear 69b and the sprocket 70b, and power from the gear 69b and the sprocket 70b is selectively applied to the output shaft 67 in accordance with the switching operation of the forward / reverse switching mechanism 71. Is transmitted. The forward / reverse switching mechanism 71 has a pair of switching disks 72a, 72b that respectively mesh with splines of the output shaft 67, and these switching disks 72a, 72b are slidable on the output shaft 67 in the axial direction. . One switching disc 72a is provided with meshing teeth 73b which engages with the meshing teeth 73a provided on the side face of the gear 69b, and the other switching disc 72b is provided with meshing teeth provided on the side face of the sprocket 70b. A meshing tooth 74b that engages with the tooth 74a is provided. Accordingly, when the pair of switching disks 72a and 72b are moved toward the gear 69b to engage the meshing teeth 73a and 73b, the rotation of the secondary shaft 54 is transmitted to the output shaft 67 via the forward gears 69a and 69b. Is transmitted. On the other hand, when the switching disks 72a, 72b are moved toward the sprocket 70b to engage the meshing teeth 74a, 74b, the rotation of the secondary shaft 54 is transmitted to the output shaft 67 via the retreating sprockets 70a, 70b. You. As shown in FIG. 2, when the switching disks 72a and 72b are not engaged with any of the meshing teeth, the connection between the secondary shaft 54 and the output shaft 67 is cut off.
[0036]
Further, a pair of switching disks 75a and 75b which mesh with splines of the output shaft 67 are respectively mounted on the output shaft 67 so as to be slidable in the axial direction, and one of the switching disks 75b is provided with a meshing tooth provided on a gear case 66. A meshing tooth 76b is provided to engage with 76a. Therefore, when the pair of switching disks 75a and 75b are moved toward the gear case 66 to engage both the meshing teeth 76a and 76b, the output shaft 67 and the gear case 66 are fastened and the rotation of the output shaft 67 is restricted. On the other hand, as shown in FIG. 2, when the engagement of the meshing teeth 76a and 76b is released, the output shaft 67 is in a rotatable state.
[0037]
Such switching disks 72a, 72b, 75a, 75b are switched by switching holders 77, 78. The switching holders 77 and 78 are connected to the switching lever 8 of the vehicle shown in FIG. 1 via an operating link (not shown), and the switching disks 72a, 72b, 75a and 75b are switched by the operation of the switching lever 8 by an occupant. . The switching lever 8 is set to an F position corresponding to forward running, an R position corresponding to backward running, an N position corresponding to the neutral state of the drive unit 11, and a P position corresponding to the parking state of the vehicle.
[0038]
When the switching lever 8 is operated to the F position, the meshing teeth 73b of the switching disk 72a engage with the meshing teeth 73a of the gear 69b, while the switching disks 75a, 75b are in the neutral position. When the switch is operated to the R position, the meshing teeth 74b of the switching disk 72b engage with the meshing teeth 74a of the sprocket 70b, while the switching disks 75a and 75b are in the neutral position. When the switch is operated to the position N, all the switching disks 72a, 72b, 75a, 75b are set to the neutral position. It engages with 66 meshing teeth 76a.
[0039]
A gear 79a is fixed to the output shaft 67 to which power is transmitted in accordance with the operation of the switching lever 8, and a gear 79b which is always meshed with the gear 79a is fixed to the axle 68. Rear wheels 3a and 3b are connected to the end of the axle 68, and the rear wheels 3a and 3b, which are driving wheels, are driven by the axle 68. As shown in FIG. 3, a drive shaft 80 for the front wheels 2a and 2b having a gear 80a meshing with the gear 79b is rotatably supported by the transmission case 53 and the gear case 66. A front wheel output shaft 81 connected via a bevel gear 81a is rotatably supported by the gear case 66. As described above, the power from the output shaft 67 is transmitted to the front wheel output shaft 81 via the drive shaft 80, so that the front wheels 2a and 2b are driven together with the rear wheels 3a and 3b.
[0040]
As shown in FIG. 2, a brake disc 82 is attached to the output shaft 67 for braking the vehicle during traveling. A brake caliper for engaging a brake pad 83a with the brake disc 82 is mounted on the gear case 66. 83 are attached. When the occupant operates the brake lever 9 provided on the steering wheel 5, the brake caliper 83 can be driven to apply a braking force to the output shaft 67.
[0041]
As described above, since the vaporizer 32 is housed in the clean chamber 31b of the air cleaner box 28, even if the water or dust is wound up as the vehicle travels, the vaporizer 32 is kept in the clean room 31b. Without being exposed to dust or dust, the waterproofness and dustproofness of the vaporizer 32 can be dramatically improved. For this reason, the waterproof structure and the dust-proof structure provided in the vaporizer 32 can be simplified, and the cost of the air-fuel mixture supply device 27 can be reduced. In particular, in the case of the vaporizer 32 having a sliding portion exposed to the outside such as the rotating shaft 37a protruding to the outside, the waterproof structure and dustproof structure provided for the sliding portion should be reduced. Thus, the cost of the mixture supply device 27 can be further reduced.
[0042]
Further, by housing the carburetor 32 in the air cleaner box 28, the number of intake ducts connecting the carburetor 32 and the air cleaner box 28 can be reduced, and the cost of the mixture supply device 27 can be reduced. it can.
[0043]
Further, by housing the carburetor 32 in the air cleaner box 28, the carburetor 32 is not exposed to the outside air, and the influence of a change in the outside air temperature on the carburetor 32 can be suppressed. As a result, it is possible to suppress the deterioration of the engine startability at a low temperature and the decrease of the charging efficiency at a high temperature, and to stabilize the performance of the carburetor 32.
[0044]
Further, by housing the vaporizer 32 in the air cleaner box 28, the vaporizer 32 is not exposed to ultraviolet rays or the like, and the deterioration of the resin member or the rubber member provided in the vaporizer 32 is suppressed. it can.
[0045]
The present invention is not limited to the above embodiment, and can be variously modified without departing from the gist thereof. For example, the illustrated air-fuel mixture supply device 27 is mounted on an ATV, that is, an off-road vehicle, but the air-fuel mixture supply device 27 may be mounted on a motorcycle or the like.
[0046]
The throttle cable 39 is guided through the input side intake pipe 29 into the air cleaner box 28 to prevent dust and the like from entering the clean chamber 31b. However, a through hole is formed in the wall of the air cleaner box 28. Then, the throttle cable 39 may be guided into the air cleaner box 28 from the through hole. In this case, it goes without saying that dust is prevented from entering by closing the gap between the throttle cable 39 and the through hole.
[0047]
Further, the illustrated carburetor 32 is a diaphragm-type carburetor 32 that opens and closes the venturi section 33c in response to a negative pressure in the output side intake pipe 30, but forcibly opens and closes the venturi section directly via a throttle cable. It may be a vaporizer of the type.
[0048]
Further, the illustrated engine 25 is a single-cylinder four-cycle engine, but may be provided with a plurality of cylinders, or may be a two-cycle engine in which the air-fuel mixture is supplied to a cylinder or a crankcase.
[0049]
Further, the engine 25 is not limited to an air-cooled engine in which the radiation fins 26 are formed on the cylinder 14 or the cylinder head 15, but may be a water-cooled engine that cools through a radiator or an oil-cooled engine that cools through an oil cooler. Needless to say, there is no problem.
[0050]
【The invention's effect】
According to the present invention, since the vaporizer is housed in the clean room of the air cleaner box, the vaporizer is not exposed to water or dust, and the waterproofness and dustproofness of the vaporizer of the air-fuel mixture supply device are reduced. It can be dramatically increased.
[0051]
Thereby, the waterproof structure and the dust-proof structure provided in the vaporizer can be simplified, and the cost of the air-fuel mixture supply device can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a vehicle.
FIG. 2 is a schematic diagram showing an engine unit and a drive unit mounted on the vehicle of FIG.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
[Explanation of symbols]
15a Combustion chamber
25 Engine
27 Mixture supply device
28 air cleaner box
29 Input side intake pipe
30 Output side intake pipe
31 Air filter
31a dust chamber
31b Clean room
32 vaporizer
39 Throttle cable

Claims (2)

An air-fuel mixture supply device for supplying an air-fuel mixture to a combustion chamber of an engine,
An air cleaner box including an input-side intake pipe communicating with the outside and an output-side intake pipe communicating with a combustion chamber of the engine;
An air filter housed in the air cleaner box and partitioning the inside of the air cleaner box into a dust chamber on the input side and a clean chamber on the output side,
A vaporizer that is housed in a clean room of the air cleaner box, and has a carburetor that mixes fuel with air in the clean room and feeds the mixture into the output-side intake pipe. The air-fuel mixture supply device according to claim 1, wherein a throttle cable for operating the carburetor is drawn into the air cleaner box from the input-side intake pipe.

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