JP5091901B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle in which a canister for adsorbing and desorbing fuel gas generated in a fuel tank is interposed in a gas path between a fuel tank and an engine.

  Fuel gas is adsorbed by activated carbon or the like, the fuel gas adsorbed while the engine is driven is released, and the separated fuel gas is sucked into the engine via a canister 18 through a gas path between the fuel tank 14 and the engine. A vehicle equipped with a mounted fuel gas recovery device is known (Patent Document 1).

  The canister adsorbs the vaporized fuel gas (vaporized gas) in the fuel tank and prevents it from being released into the atmosphere when refueling. The fuel gas is released and sucked into the engine and burned. If there is only one inlet pipe from the fuel tank to the canister, the fuel tank is full or close to full. When the vehicle body is tilted back and forth or left and right, or when accelerating, braking, turning, etc. (these are called when the vehicle body is tilted), the liquid level entering the introduction pipe (gas path) leading to the canister rises. For this reason, in order to prevent liquid fuel from flowing into the canister through the introduction pipe, it is necessary to divert the hose to a considerably high position.

JP 2008-8238 A

  An object of the present invention is to prevent liquid fuel in a fuel tank from unexpectedly flowing into a canister even when a large vehicle body tilt occurs when the fuel is full.

[Configuration of the first invention]
According to the first aspect of the present invention , an arch-shaped lops frame is disposed on the left and right behind the driver seat, the fuel gas evaporated in the fuel tank is adsorbed, the fuel gas adsorbed while the engine is driven is released, and the released fuel gas is released. In a work vehicle in which a canister is interposed in a gas path between the fuel tank and the engine, the gas path between the fuel tank and the canister is disposed in the fuel tank. A transpiration gas separation tank for recovering the transpiration fuel gas is provided, the transpiration gas separation tank is disposed at a position higher than the fuel tank, and connection ports formed at a plurality of positions separated from each other on the upper surface of the fuel tank the transpiration a suction port of the gas separation tank communicatively connected, Ri said the discharge port of the vaporized gas separation tank and the canister communicatively connected tare, the transpiration gas and Separating tank is disposed in the front-rear direction within the width of the Ropusufuremu in a side view, that is attached to the Ropusufuremu is disposed inside the Ropusufuremu in the width direction of the working vehicle in the longitudinal direction viewed Features.

[Operation of the first invention]
According to the first aspect of the invention, when the engine is operated, the fuel gas adsorbed on the canister is separated and sucked into the engine. While the engine is stopped, the fuel gas vaporized in the fuel tank is guided to the canister and collected by adsorption. When fuel is supplied to the fuel tank, the vaporized fuel gas in the fuel tank is guided to the canister through the transpiration gas separation tank and collected. In this case, for example, if only a single gas path from the fuel tank is connected to the transpiration gas separation tank, when the liquid level rises due to fuel replenishment, the gas on the liquid level due to the inclination of the ground, etc. If the fuel gas is confined in the closed space, the fuel gas in the confined space cannot be recovered by the canister. The liquid fuel may be pushed up to the transpiration gas separation tank due to the thermal expansion of the air mixture gas. In the first invention, a plurality of connection ports separated from the upper surface of the fuel tank are connected to the transpiration gas separation tank. Therefore, the fuel gas is not trapped in the tank during refueling, so the liquid fuel does not rise to the transpiration gas separation tank, and the fuel gas is used for transpiration gas separation. It can be guided to the canister through the link.

[Effect of the first invention]
Therefore, according to the first aspect of the present invention, the fuel gas in the fuel tank can be satisfactorily guided to the canister during refueling.

[Configuration of the second invention]
According to a second aspect of the present invention, the rops frame is configured to be foldable in the middle in the vertical direction, and the vaporized gas separation tank is attached to the rops frame below the folding fulcrum of the rops frame.

[Configuration of the third invention]
According to a third aspect of the present invention, the transpiration gas separation tank is disposed opposite to a dust cover that forms an outside air introduction space for introducing outside air into the engine.

[Configuration of the fourth invention]
According to a fourth aspect of the present invention, the transpiration gas separation tank is attached to the rops frame via an attachment member, and the attachment member also serves as a cover that covers the transpiration gas separation tank. The vaporized gas separation tank is disposed in a space that is attached to the lops frame on the rear surface and surrounded by the inner surface of the lops frame and the cover.

[Configuration of the fifth invention]
5th invention extends the said 1st gas path which connects the said fuel tank and the said transpiration | evaporation gas separation tank upward along the vehicle body inner side surface of the said LOSS flame | frame, The said transpiration | evaporation gas separation tank, A second gas path connecting the canister is extended downward along the lops frame.

[Configuration of the sixth invention]
The sixth invention, the engine is disposed behind the OPERATION seat, are disposed said canister between said driver's seat engine.
[Configuration of the seventh invention]
The seventh invention, a cooling air passage for supplying cooling air before SL engine provided between the driver's seat and the engine, are disposed the canister into the cooling air passage.

1 is an overall side view of a riding mower. 1 is an overall plan view of a riding mower. It is a principal part side view of the inside of an engine room, and an external air introduction part. It is a cross-sectional top view which shows the principal part of an external air introduction part. It is a vertical front view which shows arrangement | positioning of a canister and an oil cooler. It is a principal part side view which shows arrangement | positioning of a fuel tank and the tank for transpiration | evaporation gas separation. It is a principal part front view which shows arrangement | positioning of the cooling pipe of a canister and an oil cooler. The cover structure of the transpiration gas separation tank is shown, (a) is a longitudinal front view, (b) is a side view, and (c) is a plan view. It is a vertical side view of a transpiration gas separation tank. It is a vertical side view of the principal part which shows the state in which the liquid fuel infiltrated into the transpiration gas separation tank. It is a block diagram which shows the movement system of a fuel. It is a rear view which shows the state which attached the spark arrester to the exhaust pipe of the muffler. It is a rear view which shows the removal state of a spark arrester. It is a principal part side view which shows arrangement | positioning of the fuel tank in another embodiment, the tank for transpiration | evaporation gas separation, and 2 way valve | bulb. It is a systematic diagram which shows the function of the 2 way valve in another embodiment. It is a principal part rear view which shows arrangement | positioning of the transpiration gas separation tank and 2 way valve | bulb in another embodiment. It is a principal part side view which shows arrangement | positioning of the fuel tank in another embodiment, the tank for transpiration | evaporation gas separation, and 2 way valve | bulb. It is a rear view which shows arrangement | positioning of the canister in another embodiment. It is a side view which shows arrangement | positioning of the canister in another embodiment.

  Hereinafter, an embodiment in which the present invention is applied to a riding mower as an example of a work vehicle will be described. FIG. 1 is an overall side view of a riding mower, and FIG. 2 is an overall plan view. As shown in FIGS. 1 and 2, the riding mower illustrated in this embodiment includes a link mechanism 4 between a pair of left and right front wheels 2 and a pair of left and right rear wheels 3 in the traveling vehicle body 1. By arranging the mower 5 to be movable up and down, it is configured in a mid-mount type.

  The traveling vehicle body 1 is provided with a front frame 6 made of a square pipe material or the like on the front side thereof. The front frame 6 supports the link mechanism 4, and the left and right front wheels 2 are arranged at the left and right end portions of the front end portion so as to be capable of following and steering around the vertical axis. The link mechanism 4 moves the mower 5 up and down in parallel by the operation of a hydraulic cylinder (not shown).

The front frame 6 is provided with a boarding step 8 made of sheet metal so as to cover substantially the whole from above. The boarding step 8 has a rubber mat (not shown) laid on the surface thereof, a brake pedal 9 urged to return to the non-braking position at the center of the front, and a brake against the urging. A lock pedal 10 is provided that enables the pedal 9 to be locked and held at the braking position. A driver's seat 11 is disposed on the upper rear side of the boarding step 8 so that the position can be adjusted. A fender 12 and a shift lever 13 are respectively provided on the left and right sides of the driver seat 11. An arch-shaped lops frame 14 is provided behind the driver seat 11. That is, in this riding mower, the boarding operation unit 15 is formed on the front side of the traveling vehicle body 1.

  As shown in FIGS. 1 to 4, a rear frame 16 connected to the rear end portion of the front frame 6 is disposed at the rear portion of the traveling vehicle body 1. The rear frame 16 includes a pair of left and right side members 17 made of sheet metal, a mounting table 18 supported on the rear side of the left and right side members 17, and the like. An air-cooled gasoline engine 19 is mounted on the mounting table 18 in such a posture that its output shaft 20 protrudes toward the front side of the vehicle body.

  A transmission device (an example of a transmission) 21 is provided in front of and under the engine 19 to decelerate the power from the engine 19 and divide it into traveling and working. Inside the transmission device 21, a clutch (not shown) for interrupting working power is provided. A hydrostatic continuously variable transmission (an example of a transmission, hereinafter abbreviated as HST) 22 to which traveling power from the transmission 21 is transmitted is connected to the left and right sides of the transmission 21. ing. A speed reducer 23 to which power after shifting by the corresponding HST 22 is transmitted is connected to the laterally outer portion of each HST 22. Each reduction gear 23 is equipped with a corresponding rear wheel 3 so as to be capable of transmission. Each HST 22 has its speed change operation shaft (not shown) linked to the corresponding speed change lever 13 so that the speed change operation is performed based on the swing operation of the corresponding speed change lever 13 in the front-rear direction.

  With this configuration, by swinging the left and right shift levers 13 in the front-rear direction, the HST 22 corresponding to each operation lever 13 can be shifted, and the left and right rear wheels 3 can be driven to shift independently. it can.

  That is, in this riding type mower, the left and right rear wheels 3 are stopped by installing the left and right front wheels 2 so as to be able to follow and steer the left and right rear wheels 3 so that they can be driven independently. One of the left and right rear wheels 3, a straight traveling state in which the left and right rear wheels 3 are driven forward or backward at a constant speed, a slow turning state in which the left and right rear wheels 3 are driven forward or backward at different speeds, And a pivot turning state in which the other is driven forward or backward, and a spin turning state in which one of the left and right rear wheels 3 is driven forward and the other is driven in reverse. Can appear.

  A PTO shaft 24 that allows the working power to be taken out from the mower 5 is provided at the front lower portion of the transmission device 21. The PTO shaft 24 transmits working power from the transmission device 21 to the mower 5 via a transmission shaft (not shown) and a universal joint (not shown) that can expand and contract. That is, constant speed power is transmitted to the mower 5 regardless of the traveling speed and the traveling state.

A rear cover 27 formed to have left and right side walls 27A and a rear wall 27B is provided at the rear end of the rear frame 16. A plurality of exhaust holes 28 are formed in the rear wall 27 </ b> B of the rear cover 27. An upper cover 29 that covers the upper portion of the engine 19 from above is connected to the rear cover 27 so as to be able to open and close with the upper end portion of the rear cover 27 as a fulcrum. The upper cover 29 has a plurality of exhaust holes 30 formed in the rear wall 29A thereof. A partition wall 32 that forms an engine room 31 together with the rear cover 27 and the upper cover 29 is erected on the side member 17 of the rear frame 16. A muffler 33 is provided behind the engine 19.

  The muffler 33 has a substantially cylindrical outer shape arranged on the left and right. An exhaust pipe 57 formed in the shape of a “shi” in a rear view is extended toward the other end side of the muffler 33 in a state of being attached to the lower side of the muffler 33. At the rear end of the exhaust pipe 57, a large-diameter exhaust pipe 58 for reducing the exhaust temperature having a diameter larger than that of the exhaust pipe 57 is disposed in a shape that bends backward. The large-diameter exhaust pipe 58 is inserted into the upper right end portion of the exhaust pipe 57, and the upper end side is fixed to the muffler 33 with a bolt, and the lower end side is fixed to a stay 59 attached to the engine 19 with a bolt. Yes. The large-diameter exhaust pipe 58 is provided in order to mute the air while allowing air to flow in between the exhaust pipe 57 and the exhaust pipe 57 to reduce exhaust.

  A spark arrester 77 is fixed to the rear end of the exhaust pipe 57. The spark arrester 77 is provided to prevent discharge of sparks from the exhaust pipe 57. An outer cylindrical portion 78 of the spark arrester 77 is screwed to the rear end portion of the exhaust pipe 57. The tip end side of the conical mesh portion 79 of the spark arrester 77 is inserted into the exhaust pipe 57 and is extinguished by applying sparks thereto. The spark arrester 77 can be removed by removing the large-diameter exhaust pipe 58, removing the large-diameter exhaust pipe 58, and removing the spark arrester 77 mounting screw. Maintenance such as cleaning of the spark arrestor 77 is easy to perform.

  As shown in FIGS. 3 and 4, an engine cooling fan 34 that rotates integrally with the output shaft 20 of the engine 19 and an air guide housing 35 that covers the engine cooling fan 34 from the front are provided at the front of the engine 19. Equipped. The engine cooling fan 34 sucks outside air into the air guide housing 35 through a circular air inlet 37 formed on the front surface of the air guide housing 35 by the rotation, and uses the sucked outside air as cooling air. Flow toward the engine 19. The air guide housing 35 guides the cooling air from the engine cooling fan 34 to the periphery of the engine 19 to cool the engine 19 and the muffler 33. Cooling air that has cooled the engine 19, the muffler 33, and the like is discharged out of the machine from the exhaust holes 28 of the rear cover 27 and the exhaust holes 30 of the upper cover 29.

  A dustproof plate 40 is installed between the left and right side members 17 to block the space formed on the rear side of the transmission device 21 and the left and right HSTs 22 and on the front side of the engine cooling fan 34 and the mounting table 18 from below.

  As shown in FIGS. 1 and 3, a dust removal cover 42 including a dust removal net 41 for removing dust is integrally provided between the partition wall 32 at the front end of the upper cover 29 and the driver seat 11. An outside air introduction space 43 is formed by the partition wall 32 and the dust removal cover 42, and outside air that is cleaner than the outside air introduction space 43 can be supplied to the air cleaner 76 of the engine 19 and the air inlet 37 of the air guide housing 35.

  As shown in FIGS. 3 and 4, transmission from the engine 19 to the transmission device 21 is performed via a transmission shaft 49 that is spline-fitted to the output shaft 20 so as to be relatively slidable, a pair of front and rear universal joints 50, and the like. Done.

  A hydraulic pump that sucks and pumps oil stored in the transmission device 21 and a cartridge-type first oil filter 52 that filters oil sucked by the hydraulic pump are provided at the rear lower portion of the transmission device 21. Has been. A cartridge-type second oil filter 53 that filters oil supplied to the left and right HSTs 22 is provided at the front upper portion of the transmission device 21.

  Between the partition wall 32 and the transmission device 21, there is an oil cooler 54 that cools the oil that is circulated and supplied to the transmission device 21, a hydraulic cylinder (not shown), the left and right HSTs 22, and a hydraulic clutch (not shown). Has been deployed. The oil cooler 54 is disposed in the cooling air passage 55 between the engine 19 and the transmission 21 below the outside air introduction space 43, and the cooling pipe 56 constituting the oil cooler 54 is formed in a vertically folded manner in the left-right direction. When the lower side of the universal joint 50 is straddled, the portion that overlaps with the engine cooling fan 34 as viewed in the front-rear direction is increased.

  Accordingly, the oil cooler 54 is easily cooled by the engine cooling air passing through the outside air introduction space 43 and the cooling air passage 55 of the oil cooler 54. The lower part of the oil cooler 54 sucks forward air, and the cooling air flows into the intake port 37 of the air guide housing 35 together with the cooling air passing through the outside air introduction space 43 and is supplied to the engine 19.

  Fuel tanks 60, 60 that contain gasoline are disposed at the upper part of the left and right rear wheels 3, 3 at the lower rear of the left and right fenders 12, 12. The left and right fuel tanks 60, 60 are formed in a shape that avoids the rops frame 14, are long in the front-rear direction, and the left fuel tank 60 has a larger capacity than the right fuel tank 60. Connection members 68 of a hose 73 serving as a connection port are attached to two front and rear portions of the front and rear ends of the upper surfaces of the left and right fuel tanks 60.

  The gasoline in the fuel tank 60 is partially vaporized in the tank. Vaporized vaporized gas (fuel gas) is sucked and burned in the intake stroke of the engine 19. FIG. 11 is a block diagram for explaining the flow of outside air and transpiration gas in the fuel supply system. The gas path 73, 74, 63, 64 between the fuel tank 60 and the engine 19 is provided with a transpiration gas separation tank 65 and a canister 66. The vaporized gas (vaporized fuel gas) generated in the fuel tank 60 passes through the vaporized gas separation tank 65, is adsorbed by the canister 66, and the fuel gas separated from the canister 66 during the intake stroke of the engine 19 together with the air Of cylinders (this is simply referred to as engine 19). Liquid fuel (gasoline) is supplied from the fuel tank 60 to the engine 19 through the fuel path 67.

  The transpiration gas separation tank 65 is for recovering the fuel gas evaporated in the fuel tank 60 and sending it to the canister 66, and is interposed between the gas paths 73 and 74 between the fuel tank 60 and the canister 66. Has been. The transpiration gas separation tank 65 is disposed at a position higher than the fuel tank 60. Specifically, a cover 69 that surrounds the transpiration gas separation tank 65 is disposed inward from the front and rear surfaces of the lops frame 14, and the cover 69 is bent in a space surrounded by the cover 69 and the lops frame 14. The strip 69 a and the mounting strip 65 a formed on the upper part of the transpiration gas separation tank 65 are connected by a bolt 83, and the transpiration gas separation tank 65 is attached to the cover 69.

  As shown in FIG. 8, bolt holes penetrating in the front-rear direction are formed in the left and right intermediate portions of the lops frame 14. Bolt holes that coincide with the bolt holes 85 are formed in the front and rear side plates of the cover 69, and a positioning bracket 86 is fixedly attached to the rear side plate of the cover 69 so as to contact the inner side surface of the lops frame 14. is there. In a state where the bolt holes on the Lops frame 14 side and the bolt holes on the front and rear side plates of the cover 69 are aligned, the bolts 84 are inserted and fastened and fixed with nuts 85. That is, the cover 69 also serves as an attachment member for the vaporized gas separation tank 65 to the LOSS frame 14.

At the lower end of the transpiration gas separation tank 65, two hose connection members 70, 70 as suction ports for connecting to the two hose connection members 68 attached to the front and back of the upper surface of the fuel tank 60 are attached. ing. By providing the two purging hose connection members 68 in the fuel tank 60, it becomes difficult for air to accumulate, and the system can be constructed without being restricted by the tank shape or tank posture.

  Inside the transpiration gas separation tank 65, a float 75 for liquid level rest is incorporated. The liquid surface stationary float 75 has a circular outer shape in plan view, and a large number of irregularities (not shown) are formed on the upper and lower surfaces. Usually, the inside of the transpiration gas separation tank 65 is filled with air (outside air) or fuel gas, and when the fuel gas in the fuel tank 60 is sent to the canister 66 side, the fuel gas is floated at the liquid level. It passes through the space formed by the irregularities formed on the surface of. When gasoline (liquid fuel) flows in due to vehicle body inclination or the like, it functions to suppress the fluctuation of the liquid level.

  A shutoff valve composed of a float valve 71 is built in the upper part of the transpiration gas separation tank 65. When the gasoline (liquid fuel) flows into the transpiration gas separation tank 65 and the gasoline is filled into the transpiration gas separation tank 65, the float valve 71 is pushed up by the liquid surface stationary float 75 and discharged to the discharge port 71a. Is closed to prevent the liquid fuel from flowing into the canister 66. A connection member 72 as a connection port for connecting to the canister 66 and the hose 74 is attached to the discharge port 71a. The left and right gas passages 74 connecting the left and right vaporized gas separation tanks 65 and the left and right canisters 66 have the same inner diameter and the same length of the hose. The discharge port 71a is normally open, and when the transpiration gas separation tank 65 is filled with gasoline (liquid fuel), the float 71b is raised and closed.

  When the transpiration gas separation tank 65 is not provided, a thick connection hose must be prepared so as to cope with the sudden outflow of fuel gas from the fuel tank 60. Since the transpiration gas separation tank 65 is provided in the gas passages 73 and 74 between the fuel tank 60 and the canister 66, the fuel gas generated in the fuel tank 60 is temporarily absorbed by the transpiration gas separation tank 65. As a result, the diameter of the hose can be reduced, thereby facilitating the assembly, and since it is not necessary to store fuel gas in the purge hose, the length of the hose can be shortened and the cost can be reduced.

  The transpiration gas separation tank 65 is provided in communication with the fuel tank 60, so that when the gasoline in the fuel tank 60 is full, the transpiration gas even if gasoline overflows from the fuel tank 60 due to thermal expansion or the like. Since there is a space in the separation tank 65, the spilled gas separation tank 65 can absorb the overflow of gasoline and prevent the gasoline from overflowing outside the static tank.

  As shown in FIG. 5, the canister 66 disposed on the left side is larger than the canister 66 disposed on the right side. The canister 66 is for adsorbing the fuel gas evaporated in the fuel tank 60, separating the adsorbed fuel gas while the engine is being driven, and causing the separated fuel gas to be sucked into the engine 19. The canister 66 is interposed in the gas paths 74, 63, 64 on the lower side of the transpiration gas separation tank 65 among the gas paths 73, 74, 63, 64 between the fuel tank 60 and the engine 19. . The canister 66 corresponds to the left and right fuel tanks 60, 60, and is an engine separated from the left and right fuel tanks 60, 60 below the rear and at a substantially equidistant position to the left and right with respect to the left and right center line of the traveling vehicle body 1. In 19 cooling air passages 55, the oil cooler 54 is arranged separately to the left and right of the rear position of the oil cooler 54.

  The cooling air passage 55 flows in from the dust removal cover 42 by the air passage in which the oil cooler 54 below the outside air introduction space 43 surrounded by the dust removal cover 42 is disposed, and the engine cooling fan 34, and then flows into the oil cooler 54. This air path is introduced from the intake port 37 toward the engine 19 through the cooling air path 55.

  The cooling pipe 56 that constitutes the oil cooler 54 is arranged in a left-right direction such that it is vertically folded in the left-right direction. The upper and lower lengths of the zigzag folding are made shorter than the central portion, and the cooling pipe portions overlapping the canister 66 in a front view are arranged at a position where there are few.

[Engine running]
As shown in FIG. 11, gasoline (liquid fuel) in the fuel tank 60 is supplied to the engine 19 via the fuel path 67. When outside air is supplied to the engine 19 through the air cleaner 76, the canister 66 is trapped in the canister 66 by the action of negative pressure generated by air supply from the air cleaner 76 to the engine 19 through the gas path 64. The remaining fuel gas is removed and sucked into the gas path 64 to the engine 19 through the gas path 63, and at the same time, outside air is introduced into the canister 66.

[When the engine is stopped]
In the state where the engine 19 is stopped, the operation of the fuel injection device (not shown) is stopped. Therefore, the inflow of air from the air cleaner 76 through the gas path 64 leading to the engine 19 is also stopped, and the outside air is taken in. Disappear. When gasoline is supplied to the fuel tank 60, the vaporized gas (fuel gas) in the fuel tank 60 is discharged outside the tank. According to this embodiment, the vaporized gas separation tank 65 It is adsorbed by the canister 66 through the, and the release of the transpiration gas to the atmosphere is suppressed.

  When the riding mower is traveling on a steep slope or falls while traveling, the inside of the vaporized gas separation tank 65, which is normally filled with gas, passes through the gas path 73. When a situation in which the fuel is filled with gasoline (liquid) occurs, the discharge port is closed by the float valve 71 in the transpiration gas separation tank 65 and the liquid gasoline is prevented from flowing into the canister 66.

  As described above, by providing the vaporized gas separation tank 65 above the fuel tank 60, even if gasoline (liquid fuel) rises to the vaporized gas separation tank 65 due to the inclination of the vehicle body or the like, the vaporized gas separation tank 65 is provided. The fuel gas and gasoline (liquid fuel) are separated in the fuel gas, and only the fuel gas can be sent to the canister 66. Further, even if the amount of inflow of gasoline increases and the inside of the transpiration gas separation tank 65 is filled with gasoline, the float of the float valve 71 floats up and closes the discharge port 71a to prevent the gasoline from flowing out toward the canister 66. be able to. In order to prevent the gasoline in the fuel tank 60 from moving to the canister 66 side even when a large body inclination occurs due to sudden braking, sudden start, sudden turning, traveling on a steep slope, etc., the fuel tank 60 and the canister 66 It is necessary to raise the purge hose between the evacuated gas and the evaporative gas separation tank 65 at a high place, but in the present embodiment, since the float valve 71 is provided in the evaporative gas separation tank 65, The position of the transpiration gas separation tank 65 can be lowered.

  By incorporating the liquid level static float 75 in the transpiration gas separation tank 65, the liquid surface in the transpiration gas separation tank 65 can be prevented from being disturbed by vibrations, and a constant state can always be maintained. As a result, it is possible to prevent a slight gasoline outflow caused by the droplets scattered from the liquid level being applied to the float valve 71. In this way, the fuel gas and gasoline can be separated by the transpiration gas separation tank 65, so that only the fuel gas can be sent to the canister 66 and the gasoline can be reliably prevented from flowing out. Further, even when the traveling vehicle body 1 rolls over or falls down, when the vaporized gas separation tank 65 is filled with gasoline, the float valve 71 is closed, so that the gasoline can be prevented from flowing out to the canister 66 side.

[Another embodiment]
(1) As the gas path 73 connecting the fuel tank 60 and the transpiration gas separation tank 65, three or more plural gas paths 73 may be provided.

(2) In the above embodiment, the left and right canisters 66 partially overlap with the cooling pipe 56 of the oil cooler 54 when viewed from the front, but there is no cooling pipe 56 overlapping the canister 66 when viewed from the front. It may be.

(3) FIGS. 14 and 16 show a gas path 74 (FIG. 14) between the transpiration gas separation tank 65 and the canister 66 provided with a shut-off valve (float valve 71) in the structure of the above embodiment. 11) shows a configuration in which a 2-way valve 80 is interposed. As shown in FIG. 15, the two-way valve 80 has a configuration in which two-way check valves 81 and 82 that stop the flow until a constant positive pressure or negative pressure is incorporated in parallel. The two-way valve 80 switches the gas flow direction in the gas path 74 to a state in which only one of the transpiration gas separation tank 65 side and the canister 66 side or the opposite direction is allowed to flow. If the engine 19 is in operation, the outside air is allowed to flow from the canister 66 side through the transpiration gas separation tank 65 to the fuel tank 60 side, and if the liquid level decreases as the fuel in the fuel tank 60 is consumed, the canister Outside air flows from the 66 side to the fuel tank 60 side. When the engine 19 is stopped, outside air is not taken in. When liquid fuel (gasoline) is replenished, in a state where the inside of the fuel tank 60 is in a closed space, the internal pressure of the fuel tank 60 increases as the fuel is replenished, and the fuel tank 60 side moves toward the canister 66 side. The fuel gas flows and is collected by the adsorbent.

  In addition, by installing the two-way valve 80, an air layer can be secured in the transpiration gas separation tank 65 even when the fuel injection port is positioned higher than the upper surface of the transpiration gas separation tank 65, and Purging and intake are automatically performed according to the tank internal pressure of the transpiration gas separation tank 65 to stabilize the tank internal pressure.

  The left and right fuel tanks 60 communicate with each other via a fuel path 67 for supplying gasoline to the engine 19 as shown in FIG. 16 and 17, the transpiration gas separation tank 65 is located at a higher position above the tank liquid level line R based on the position of the hose connection member 68 on the upper surface of the fuel tank 60 when the traveling vehicle body 1 is at the maximum inclination. Shows the arrangement. Thus, when the transpiration gas separation tank 65 is arranged above the tank liquid level line R when the traveling machine body 1 is inclined to the maximum, the shutoff valve (float valve 71) can be omitted.

(4) FIGS. 18 and 19 show another embodiment in which the arrangement of the canister 66 is different from the above-described embodiment. 18 and 19, the left and right canisters 66 and 66 are disposed below the rear portions of the left and right fuel tanks 60 and 60.

(5) In the above-described embodiment, the vaporized gas separation tank 65 provided with the liquid level static float 75 is shown as an example, but the vaporized gas separation tank 65 not provided with the liquid level static float 75 is adopted. May be.

  The present invention includes a front mount mower, a tractor, an agricultural transporter, and a riding type rice transplant in addition to a mid-mount mower in which a mower 5 is disposed between left and right front wheels 2 and left and right rear wheels 3 in a four-wheel drive traveling vehicle body 1. It can be applied to machines.

DESCRIPTION OF SYMBOLS 1 Traveling vehicle body 11 Driver's seat 14 Lops frame 19 Engine 55 Cooling air path 60 Fuel tank 73 Gas path 74 Gas path 65 Transpiration gas separation tank 66 Canister 69 Mounting member (cover)
70 Suction port 71a Discharge port

Claims (7)

An arch-shaped lops frame is arranged on the left and right behind the driver's seat to adsorb the vaporized fuel gas in the fuel tank, to dissipate the adsorbed fuel gas while the engine is running, and the separated fuel gas is sucked into the engine In a work vehicle in which a canister is interposed in a gas path between the fuel tank and the engine,
The gas path between the fuel tank and the canister is provided with a transpiration gas separation tank for recovering the fuel gas evaporated in the fuel tank, and the transpiration gas separation tank is disposed at a higher position than the fuel tank. A connection port formed at a plurality of positions separated from each other on the upper surface of the fuel tank and a suction port of the transpiration gas separation tank, and a discharge port of the transpiration gas separation tank and the canister. Citea is,
The transpiration gas separation tank is disposed in the front-rear width of the lops frame in a side view, and is disposed on the inner side of the lops frame in the width direction of the work vehicle in a front-rear direction and attached to the lops frame. work vehicle, characterized in that it is. 2. The work vehicle according to claim 1 , wherein the lops frame is configured to be foldable at a midway portion in the vertical direction, and the vaporized gas separation tank is attached to the lops frame below a folding fulcrum of the lops frame . The work vehicle according to claim 1 or 2, wherein the transpiration gas separation tank is disposed to face a dust cover that forms an outside air introduction space for introducing outside air to the engine. The transpiration gas separation tank is attached to the rops frame via an attachment member, and the attachment member also serves as a cover for covering the transpiration gas separation tank, and the cover is provided on the front and rear surfaces of the rops frame. The work vehicle according to any one of claims 1 to 3 , wherein the transpiration gas separation tank is disposed in a space enclosed by an inner surface of the lops frame and the cover . The first gas path connecting the fuel tank and the transpiration gas separation tank extends upward along the vehicle body inner side surface of the LOSS frame,
The work vehicle according to any one of claims 1 to 4 , wherein a second gas path connecting the transpiration gas separation tank and the canister is extended downward along the lops frame. .   The work vehicle according to claim 1, wherein an engine is disposed behind the driver seat, and the canister is disposed between the driver seat and the engine.   The work vehicle according to claim 6, wherein a cooling air passage for supplying cooling air to the engine is provided between the engine and the driver seat, and the canister is disposed in the cooling air passage.

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