JP2015145635A - Saddle-ride vehicle evaporated fuel treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a saddle-ride vehicle evaporated fuel treatment apparatus capable of securing a canister placement space and shortening pipes, preventing a sudden change in air-fuel mixture due to purge fuel gas, and preventing the influence on engine performance and enhancing the engine performance.SOLUTION: In an evaporated fuel treatment apparatus 100 of a saddle-ride vehicle 1 in which a power unit 5 including a cylinder section 32 of an internal combustion engine 3 above a crankcase 30 is disposed below a fuel tank 8, an intake passage 6 including a carburetor 62 is disposed backward of the cylinder section 32, a canister 9 connected to the fuel tank 8 is disposed in the neighborhood of a lower portion of the carburetor 62 between the intake passage 6 and the crankcase 30, and a return purge pipe 92 from the canister 9 is detoured and connected to the intake passage 6 by extending upward from the neighborhood of the lower portion of the carburetor 62 and then forming an inverse-U section 92c in a space lateral to the intake passage 6.

Description

  The present invention relates to an evaporated fuel processing apparatus in a saddle riding type vehicle.

  When providing an evaporative fuel processing device that suppresses the evaporative fuel from being released from the fuel tank, in a straddle-type vehicle in which a power unit is disposed below the fuel tank, for example, as disclosed in Patent Document 1 below, for example, The canister that adsorbs and purges evaporative fuel is located at the rear of the internal combustion engine, ensuring both canister space and piping, and preventing sudden changes in the air-fuel mixture caused by purge fuel gas from the canister That was a challenge.

Japanese Patent No. 4918527 (FIGS. 1 to 3)

  The present invention has been made in view of the prior art, can secure a canister arrangement space and shorten piping, can prevent a sudden change in the air-fuel mixture due to the purge fuel gas from the canister, It is an object of the present invention to provide an evaporative fuel treatment device for a saddle-ride type vehicle that can prevent the influence on the engine performance and improve the engine performance.

  In order to solve the above-described problem, the invention according to claim 1 is directed to an evaporative fuel treatment for a saddle-ride type vehicle in which a power unit including a cylinder portion of an internal combustion engine is disposed above a crankcase below a fuel tank. In the apparatus, an intake passage including a carburetor is disposed behind the cylinder portion, and a canister connected to the fuel tank is disposed between the intake passage and a crankcase and in the vicinity of a lower portion of the carburetor. The return purge pipe from the canister is detoured and connected to the intake passage by forming an inverted U-shaped portion in the side space of the intake passage extending upward from the vicinity of the lower portion of the carburetor and then forming an inverted U-shaped portion. An evaporative fuel treatment apparatus for a saddle-ride type vehicle.

  According to a second aspect of the present invention, there is provided the evaporative fuel processing apparatus for a saddle type vehicle according to the first aspect, wherein the return opening portion where the return purge pipe from the canister is connected to the intake passage is the carburetor. A negative pressure limiting valve that is provided in the vicinity of the valve opening / closing portion on the upstream side of the throttle valve and that restricts purge fuel gas from the canister to the internal combustion engine according to the negative pressure on the return opening side in the return purge pipe Is provided

  According to a third aspect of the present invention, in the evaporative fuel processing apparatus for a saddle-ride type vehicle according to the second aspect, the return opening of the carburetor to which the return purge pipe is connected has a side view of the intake passage. It is located in a lower edge part, The upper end of the said reverse U-shaped part of the said return purge piping is located more than the upper edge part of the said intake passage by side view, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the evaporative fuel processing device for a saddle type vehicle according to the third aspect, the negative pressure limiting valve is attached to a support boss provided on an outer wall of the intake passage via a stay. It is characterized by that.

  According to a fifth aspect of the present invention, in the evaporative fuel processing device for a saddle-ride type vehicle according to the fourth aspect, the canister is covered by a protective cover.

  According to the evaporative fuel processing apparatus for a saddle-ride type vehicle according to the first aspect of the present invention, the canister is surrounded by the crankcase and the cylinder portion of the internal combustion engine to improve the canister's protection, and the canister is disposed under the carburetor. The return purge pipe from the canister is arranged in the vicinity of the U-shape in the side space of the intake passage so that the space for arranging the canister and the return purge pipe is secured and the difference in the height of the purge fuel gas is utilized. The engine performance can be improved by preventing a sudden return and preventing the purge fuel gas from affecting the engine performance.

  According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the purge fuel gas is limited and mixed by the simple negative pressure limiting valve at the leak negative pressure in the vicinity of the upstream side of the throttle valve during idling. The purge performance can be improved at low cost by supplying purge fuel gas by effectively utilizing the negative pressure generated in the vicinity of the throttle valve when the throttle valve opening is larger than that.

  According to the invention of claim 3, in addition to the effect of the invention of claim 2, by utilizing the vertical width of the intake passage, the pipe length of the inverted U-shaped portion is secured to further stabilize the purge performance. be able to.

  According to the invention of claim 4, in addition to the effect of the invention of claim 3, vibration of the return purge pipe is prevented by the outer wall of the intake passage through the negative pressure limiting valve, and the purge fuel gas in the return purge pipe is prevented from flowing. Disturbance is prevented and the purge performance can be improved.

  According to the invention of claim 5, in addition to the effect of the invention of claim 4, an excessive increase in the amount of vaporization in the canister due to the influence of heat from the internal combustion engine side is prevented, and the canister is in the vicinity of the internal combustion engine. The engine performance can be stabilized by the optimum purge amount.

1 is a right side view of a motorcycle including a fuel vapor processing apparatus according to an embodiment of the present invention. FIG. 2 is a right side view of an essential part around an evaporative fuel processing apparatus, with a vehicle body cover, a fuel tank shell, a vehicle body frame, and a carburetor removed in the motorcycle shown in FIG. 1. The outer shape of the vaporizer is indicated by a two-dot chain line. It is a right view of the vaporizer | carburetor in FIG. FIG. 4 is an elevational cross-sectional view of the vaporizer taken along line IV-IV in FIG. 3. It is a left view of the carburetor in FIG. It is a schematic diagram of the evaporative fuel processing apparatus of this embodiment, and is equivalent to the VI-VI arrow line view in FIG. FIG. 2 is a left side view of the main part around the evaporative fuel processing apparatus, with the vehicle body cover, the fuel tank shell, and the vehicle body frame removed, in the motorcycle shown in FIG. 1. It is the perspective view which looked at the canister in FIG. 2 from diagonally upward right. FIG. 3 is a perspective view seen from obliquely forward to the right, generally as viewed in the direction of arrow IX in FIG. 2, and is an explanatory view of attaching a return purge pipe from the canister. It is a perspective view of an intake pipe provided with a downstream side intake passage, and is shown in a state where a stay for attaching a negative pressure limiting valve of a return purge pipe is fastened to a support boss formed on the outer wall of the intake pipe.

A fuel vapor processing apparatus for a saddle-ride type vehicle according to an embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, the saddle riding type vehicle is the motorcycle 1 equipped with the power unit 5, and the directions such as front, rear, left, right, up and down in the claims and the description of the present specification are the same as those of the evaporated fuel processing apparatus 100 of the present embodiment. It shall follow the direction of the equipped vehicle (motorcycle 1).
In the figure, arrow FR indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle.

  As shown in FIG. 1 on the right side of a motorcycle 1 according to the present embodiment (“saddle-type vehicle” in the present invention), the body frame 2 of the motorcycle 1 of the present embodiment is The main frame 21 extends backward with a slight downward inclination in the center in the width direction, and then bends downward to form the main steeply inclined portion 21a. Further, the head pipe 20 further extends the center in the vehicle width direction. A down frame 22 extends obliquely rearward and downward.

The motorcycle 1 is equipped with a power unit 5 that is integrally provided with a transmission 4 at the rear part of the crankcase 30 of the internal combustion engine 3, and the front part of the crankcase 30 is attached to a support bracket 22 a below the down frame 22. The crankcase 30 is fastened at two locations, and the rear portion of the crankcase 30 is fastened to the support bracket 21b below the main steeply inclined portion 21a of the main frame 21 at two locations, so that the power unit 5 is supported by the body frame 2. .
A pair of left and right seat rails 23 extend rearward from the bent portion of the main frame 21 while forming a bent portion in the middle, and the backstay connecting the bent portion of the seat rail 23 and the central portion of the main steeply inclined portion 21a. 24 supports the seat rail 23.

  In the vehicle body frame 2 as described above, the front fork 10 is pivotally supported on the head pipe 20, the front wheel 11 is pivotally supported at the lower end thereof, the steering handle 12 is provided at the upper end of the pivot of the front fork 10, and the main frame 21 A rear fork 13 pivotally supported at the front end of a pivot shaft 25 provided at the lower part of the rear wheel 13 extends rearward, and a rear wheel 14 is pivotally supported at the rear end of the rear fork 13 between the central portion of the rear fork 13 and the backstay 24. A rear cushion 15 is interposed.

A fuel tank 8 is installed on the main frame 21 so as to straddle the left and right sides, and a seat 17 is provided behind the fuel tank 8 and supported by a seat rail 25.
A front cover 18A covers the upper part of the down frame 22 of the body frame 2 from the left and right sides, a side cover 18B covers the left and right sides between the internal combustion engine 3 and the seat 17, and a rear cover 18C covers the second half of the seat rail 25. .

Below the fuel tank 8, a power unit 5 having a cylinder portion 32 of the internal combustion engine 3 above the crankcase 30 has a crankshaft 31 oriented in the vehicle width direction of the motorcycle 1, that is, in the left-right direction. It is arranged in an upright posture with a slight forward tilt.
The internal combustion engine 3 of the present embodiment is an air-cooled single cylinder SOHC type 4-stroke cycle internal combustion engine.

  In the internal combustion engine 3, a cylinder block 33 and a cylinder head 34 are sequentially stacked and fastened at a front portion of a crankcase 30 that rotatably supports a crankshaft 31 in a slightly obliquely upward direction. Is covered with a cylinder head cover 35, and a cylinder portion 32 comprising a cylinder block 33, a cylinder head 34, and a cylinder head cover 35 is protruded from the crankcase 30 slightly forward and inclined forward as described above. .

Further, a main shaft 41 and a counter shaft 42 are provided in the rear part of the crankcase 30 in parallel with the crankshaft 31, and a plurality of sets of transmission gears (not shown) of the main shaft 41 and the counter shaft 42 are always meshed with each other. 4 is configured.
The counter shaft 42 penetrates the crankcase 30 to the left and protrudes to the outside to be the final output shaft of the power unit 5, and the output sprocket 26 is spline fitted to the protruding portion.
A drive chain 27 wound around the output sprocket 26 is stretched over a driven sprocket 14a on the rear wheel 14 side to form a chain transmission mechanism, and power is transmitted to the rear wheel 14.

  The exhaust pipe 36 extending forward from the cylinder head 34 is bent downward and further bent rearward, and is arranged on the right side of the rear wheel 14 rearward and rightward along the lower surface of the crankcase 30. 37.

FIG. 2 shows the right side of the motorcycle 1 shown in FIG. 1 with the side cover 18B, the shell 8a of the fuel tank 8 and the vehicle body frame 2 removed, and the carburetor 62 has only an outer shape. Indicated by the dotted line.
A metal intake pipe 61 is connected to the intake port 34a of the cylinder head 34 and extends rearward to be connected to the carburetor 62. The carburetor 62 is located rearward via a hard rubber connecting tube 63. It is connected to an upstream air cleaner case 64.

  That is, the downstream side intake passage 6C in the intake pipe 61 and the upstream side intake passage 6A in the connecting tube 62 across the cab intake passage 6B in the carburetor 62 are rearward from the cylinder portion 32 of the internal combustion engine 3. An intake passage 6 (6A, 6B, 6C) is formed which is connected between the air cleaner case 63 and the intake port 34a of the cylinder head 34 and includes a carburetor 62.

The carburetor 62 of the present embodiment has a front and rear as shown in FIG. 3 showing the right side thereof, FIG. 4 showing an elevational cross section taken along arrow IV-IV in FIG. 3, and FIG. This is a known negative pressure actuated carburetor having a throttle valve 65 and a venturi part by a negative pressure actuated venturi piston (not shown) in the cab intake passage 6B arranged in the direction, and below the venturi part, A float chamber 66 for temporarily storing fuel at a constant liquid level until fuel is supplied to the cab intake passage 6B is provided.
Fuel which is constantly pressurized and supplied to the float chamber by gravity drop from the fuel tank 8 is supplied from the fuel receiving port 67 (see FIG. 5) to the float chamber 66 through the fuel supply pipe 81 (see FIG. 2).

The motorcycle 1 of the present embodiment includes an evaporated fuel processing apparatus 100 for performing gas processing without directly releasing the evaporated fuel gas generated in the fuel tank 8 to the atmosphere.
As schematically shown in FIG. 6 corresponding to a view taken along the line VI-VI in FIG. 8, the evaporated fuel processing apparatus 100 of the present embodiment is configured by a canister 9 and piping connected thereto.
The canister 9 is a cylindrical container containing an adsorbent such as activated carbon. In the present embodiment, the canister 9 has an intake pipe 61 and a crankcase 30 that form a downstream intake passage 6C with the cylindrical axis oriented in the vehicle width direction. It is arranged in the vicinity of the lower part of the vaporizer 62 and is attached to the main frame steeply inclined portion 21a of the motorcycle 1 (see FIGS. 1 and 8).

One end 91a of a charge pipe 91 is connected to the approximate center of the right end portion 9a of the canister 9, and a breather pipe 82 for leading evaporated fuel gas from the fuel tank 8 is connected to the other end 91b of the charge pipe 91 (see FIG. 2). ), The canister 9 is connected to the fuel tank 8.
When the motorcycle 1 is parked or the like, the evaporated fuel gas generated by warming the fuel in the fuel tank 8 is sent into the canister 9 via the breather pipe 82 and the charge pipe 91, and is sent to the adsorbent in the canister 9. Adsorbed.

Further, one end 92a of the return purge pipe 92 is connected to the front part of the right end part 9a of the canister 9 in front of the charge pipe 91, and the other end 92b of the return purge pipe 92 is connected to the return opening of the vaporizer 62. 68 (see FIGS. 3 and 4).
The adsorbed evaporated fuel gas is purged by the negative pressure of the intake system generated by the operation of the internal combustion engine 3, returned to the intake passage 6 through the return purge pipe 92 (see FIG. 2), and burned in the internal combustion engine 3. Gas purification is done

  A fresh air introduction pipe 93 and a drain pipe 94 communicating with the atmosphere are connected to the left end 9 b of the canister 9. The fresh air introduction pipe 93 introduces outside air into the canister 9 when the evaporated fuel gas adsorbed by the adsorbent is purged, and facilitates purging. The drain pipe 94 discharges unnecessary gas and liquid in the canister 9 at the time of adsorbing the evaporated fuel gas to facilitate the adsorption.

As shown in FIG. 7, the outer end 93b of the fresh air introduction pipe 93 is inserted into the recess 51 of the battery case 50 located at the rear of the canister 9, which simplifies the support structure and separates the fuel from the road surface. The position surrounded by the tank 8, the seat 17, the side cover 18B, etc. (see FIG. 1) suppresses the influence of dust contamination and the heat of the internal combustion engine when introducing fresh air.
Further, the drain pipe 94 extends below the rear part and reaches the lower part of the crankcase 30, and the outer end 94b is opened downward at the lower part of the vehicle body, thereby suppressing the influence of the drained gas and liquid on the vehicle body and the occupant. doing.

As shown in FIG. 2, a breather pipe 82 for deriving the evaporated fuel gas generated in the fuel tank 8 extends downward from the gas-liquid separator provided in the fuel cap 80 at the upper part of the fuel tank 8. ing.
On the other hand, the cylindrical canister 9 whose central axis is oriented in the vehicle width direction is between the intake pipe 61 that forms the downstream intake passage 6C and the crankcase 30 (see FIG. 1), and below the carburetor 62. The other end of the charge pipe 91 that is disposed in the vicinity and that is connected to the center of the right end portion 9a of the canister 9 and that passes through the lower side of the connecting tube 62 that forms the upstream side intake passage 6A and extends upward. A breather tube 82 is connected to the end 91b.
Therefore, the evaporated fuel gas generated from the fuel tank 8 as described above is sent into the canister 9 through the breather pipe 82 and the charge pipe 91 and is adsorbed by the adsorbent.

Further, one end 92 a of the return purge pipe 92 is connected to the front part of the right end portion 9 a of the canister 9 so as to be located in front of the charge pipe 91, and the other end 92 b of the return purge pipe 92 is connected to the return opening of the vaporizer 62. It is connected to the unit 68 (see FIGS. 3 and 4).
As shown in FIGS. 3 and 4, the return opening 68 is located at the lower edge 6 </ b> Bb of the cab intake passage 6 </ b> B in the carburetor 62 in a side view, and one end side is the other end of the return purge pipe 92. An axial hole 68a formed in the nozzle portion to which 92b is connected and formed in the nozzle portion and the wall portion of the carburetor 62 in the axial direction of the in-cab intake passage 6B in the carburetor 62, and an axial hole 68a And a communication hole 68b formed in the wall portion of the carburetor 62 toward the cab intake passage 6B.
The outer end of the communication hole 68b is closed with a plug member 69.

  The inward end of the communication hole 680b opens in the vicinity of the valve opening / closing part 6Bc on the upstream side of the throttle valve 65 of the carburetor 62. That is, the return opening portion 68 is provided so as to open in the vicinity of the valve opening / closing portion 6Bc on the upstream side of the throttle valve 65 of the carburetor 62, and the return purge pipe 92 is connected via the axial hole 68a and the communication hole 68b. It is connected to the cab intake passage 6B, that is, the intake passage 6.

Further, the return purge pipe 92 bypasses by forming an inverted U-shaped portion 92c after extending upward from the vicinity of the lower portion of the carburetor 62 in the right side space of the intake pipe 61 that forms the downstream side intake passage 6C. After securing the pipe length, it is connected to the nozzle portion of the return opening 68.
The upper end of the reverse U-shaped portion 92c of the return purge pipe 92 is located above the upper edge portion 6Ca of the downstream side intake passage 6C in the intake pipe 61 as viewed from the side, as shown in FIGS. (See also FIG. 9).
Therefore, the inverted U-shaped portion 92c moves up and down between the lower edge portion 6Bb of the cab intake passage 6B and the upper edge portion 6Ca of the downstream intake passage 6C, so that the intake passage 6 (6B 6C), the pipe length of the inverted U-shaped portion 92c is secured to further stabilize the purge performance.

As described above, in the present embodiment, the canister 9 is surrounded by the crankcase 30 and the cylinder portion 32 of the internal combustion engine 3, so that the protection of the canister 9 is enhanced.
Since the canister 9 is disposed in the vicinity of the lower portion of the carburetor 62, the return purge pipe 92 from the canister 6 is disposed in an inverted U shape in the right side space of the intake pipe 61 that forms the downstream intake passage 6C. Further, a space for arranging the canister 9 and the return purge pipe 92 is ensured, and a rapid return of the purge fuel gas is prevented by utilizing the height difference of the pipe length, and the liquid fuel condensed even in the vibration and inclination of the motorcycle 1 Is prevented from flowing into the intake passage 6 from the canister 9, and the engine performance can be improved by preventing the purge fuel gas from affecting the engine performance.

Further, the return purge pipe 92 is provided with a negative pressure limiting valve 7 for limiting the purge fuel gas sucked from the canister 9 through the intake passage 6 into the internal combustion engine 3 according to the negative pressure on the return opening 68 side. It has been.
The negative pressure limiting valve 7 is a one-way valve that allows the purge fuel gas to flow from the canister 9 side to the return opening 68 side of the carburetor 62 only when the return opening 68 side has a negative pressure of a certain level or more.

That is, the return opening 68 opens in the vicinity of the valve opening / closing portion 6Ba on the upstream side of the throttle valve 65 with respect to the in-cab intake passage 6B of the carburetor 62, and in the vicinity of the upstream side of the throttle valve 65 during idling. In the range of the leak negative pressure, the negative pressure limiting valve 7 limits the inflow of the purge fuel gas to prevent the variation of the air-fuel mixture due to the unstable leak negative pressure.
When the throttle valve 65 is opened beyond a certain level, a negative pressure exceeding a certain level is generated at the return opening 68. Therefore, the negative pressure limiting valve 7 is opened and a negative pressure generated in the vicinity of the throttle valve 65 is generated. The purge fuel gas can be supplied by effectively utilizing the pressure, and the purge performance can be improved at low cost by the simple negative pressure limiting valve 7. Further, blown-back gas from the vaporizer 62 side is also prevented.

As shown in FIG. 9, the negative pressure limiting valve 7 has a substantially cylindrical shape and is interposed in a return purge pipe 92 that passes through the side of the intake pipe 61, but is itself sandwiched by an annular rubber band 71. Is done.
Further, a fixed projection 73 having a fitting hole 72 in the tangential direction is integrally formed on the outer surface of the rubber band 71.
On the other hand, as shown in FIG. 10, a support boss 61b is integrally provided on the side wall 61a of the intake pipe 61, that is, the outer wall 61a of the intake passage 6 (downstream intake passage 6C), and is provided on the support boss 61b. A valve mounting stay (“stay” in the present invention) 61 d is fastened by a bolt 61 c screwed into the female screw hole.

A fitting protrusion 61e is provided at the tip of the valve mounting stay 61d. By fitting the fitting protrusion 61e into the fitting hole 72 of the rubber band 71 as shown in FIG. It is easily attached to a support boss 61b provided on the outer wall 61a of the downstream side intake passage 6C via a valve attachment stay 61d.
Therefore, since the return purge pipe 92 is supported by the outer wall 61a of the downstream side intake passage 6C via the negative pressure limiting valve 7, the return purge pipe 92 is prevented from vibrating, and the purge fuel gas in the return purge pipe 92 is disturbed. This is prevented and the purge performance is improved.

Further, as shown in FIG. 8 (see FIG. 6), the canister 9 is held in a cylindrical hard rubber protective cover 95 with the left end side released (see FIG. 7) and the right end side substantially released. The front and lower sides in the circumferential direction are covered with the cylindrical portion 95a of the protective cover 95.
Therefore, the canister 9 is disposed between the intake pipe 61 that forms the downstream side intake passage 6C and the crankcase 30 and in the vicinity of the rear of the cylinder portion 32 of the internal combustion engine 3, while the canister 9 An excessive amount of vaporization in the canister 9 due to the influence is prevented, and the engine performance can be stabilized by the optimum purge amount.

Further, a fixed projection 97 having a fitting hole 96 in the tangential direction is integrally formed on the upper portion of the cylindrical portion 95 a of the protective cover 95.
On the other hand, as shown in FIG. 8, the main steep inclined portion 21a of the main frame 21 adjacent to the rear portion of the canister 9 is provided with a canister mounting stay 28 on the side facing the canister 9, and the canister mounting stay 28 is provided. A fitting protrusion 28a is provided at the tip of the canister 9, and the canister 9 is attached to the canister mounting stay 28 provided on the main steeply inclined portion 21a by fitting the fitting protrusion 28a into the fitting through hole 96 of the protective cover 95. Easy to attach through the protective cover 95

The characteristics of the evaporated fuel processing apparatus 100 of the motorcycle 1 according to this embodiment will be described below.
That is, in the evaporative fuel processing apparatus 100 of the motorcycle 1 in which the power unit 5 including the cylinder portion 32 of the internal combustion engine 3 is disposed below the fuel tank 8 with respect to the crankcase 30, vaporization is performed rearward from the cylinder portion 32. The canister 9 connected to the fuel tank 8 is disposed between the intake pipe 61 having the downstream intake passage 6C and the crankcase 30 and is vaporized. In the side space of the intake pipe 61 having the downstream intake passage 6C, the return purge pipe 92 disposed near the lower part of the canister 9 extends upward from the vicinity of the lower part of the carburetor 62 and then reverse U-shaped. By forming the portion 92c, it bypasses and is connected to the cab intake passage 6B.

  Therefore, the canister 9 is surrounded by the crankcase 30 and the cylinder portion 32 of the internal combustion engine 3 to enhance the protection of the canister 9, and the canister 9 is disposed near the lower portion of the vaporizer 62 and the return purge pipe from the canister 9 is provided. 92 is formed in an inverted U shape in the side space of the intake pipe 61 having the downstream side intake passage 6C, and the space for arranging the canister 9 and the return purge pipe 92 is secured, and the height of the purge fuel gas is utilized by utilizing the difference in the height of the pipe. The engine performance can be improved by preventing a sudden return and preventing the purge fuel gas from affecting the engine performance.

  A return opening 68 through which the return purge pipe 92 from the canister 9 is connected to the cab intake passage 6B is provided in the vicinity of the valve opening / closing part 6Bc on the upstream side of the throttle valve 65 of the carburetor 62. Is provided with a negative pressure limiting valve 7 for limiting the purge fuel gas from the canister 9 to the internal combustion engine 3 according to the negative pressure on the return opening 68 side.

  Therefore, the simple negative pressure limiting valve 7 limits the purge fuel gas at the leak negative pressure in the vicinity of the upstream side of the throttle valve 65 during idling to prevent the variation of the air-fuel mixture, and the opening of the throttle valve 65 beyond that. The purge performance can be improved at low cost by effectively using the negative pressure generated in the vicinity of the throttle valve 65 to supply the purge fuel gas.

  The return opening 68 of the carburetor 62 to which the return purge pipe 92 is connected is located at the lower edge 6Bb of the cab intake passage 6B in a side view, and the upper end of the inverted U-shaped portion 92c of the return purge pipe 92 is Since it is located above the upper edge portion 6Ca of the downstream side intake passage 6C in side view, the vertical length of the intake passage 6 (6B, 6C) is used to secure the pipe length of the inverted U-shaped portion 92c. Thus, the purge performance can be further stabilized.

  The negative pressure limiting valve 7 is attached to a side wall 61a of the intake pipe 61 having the downstream side intake passage 6C, that is, a support boss 61b provided on the outer wall 61a of the downstream side intake passage 6C via a valve mounting stay 61d. Therefore, the vibration of the return purge pipe 92 is prevented by the outer wall 61a of the downstream side intake passage 6C via the negative pressure limiting valve 7, the disturbance of the purge fuel gas in the return purge pipe 92 is prevented, and the purge performance is improved. .

  Since the canister 9 is covered below by the protective cover 95, an excessive amount of vaporization in the canister 9 due to the influence of heat from the internal combustion engine 3 side is prevented, and the canister 9 is in the vicinity of the internal combustion engine 3. However, the engine performance can be stabilized by the optimum purge amount.

The evaporative fuel processing apparatus for a saddle-ride type vehicle according to an embodiment of the present invention has been described above. However, the aspect of the present invention is not limited to the above-described embodiment, and can be implemented in various aspects within the scope of the present invention. Of course, it is included.
For example, the straddle-type vehicle of the present invention is not limited to the motorcycle according to the embodiment, and may be a variety of straddle-type vehicles such as a three-wheel and a four-wheel buggy. Any riding vehicle may be used.
In addition, the arrangement of the left and right of each device has been described specifically for illustration, for convenience of explanation, but the arrangement may be reversed to that shown in the above embodiment, and is included in the present invention. .

  DESCRIPTION OF SYMBOLS 1 ... Motorcycle ("saddle type vehicle" in this invention), 2 ... Body frame, 3 ... Internal combustion engine, 4 ... Transmission, 5 ... Power unit, 6 ... Intake passage, 6A ... Upstream intake passage, 6B ... Cab Inner intake passage, 6Bb ... lower edge portion, 6Bc ... valve opening / closing portion, 6C ... downstream intake passage, 6Ca ... upper edge portion, 7 ... negative pressure limiting valve, 8 ... fuel tank, 9 ... canister, 21 ... main frame, 21a ... main steeply inclined portion, 28 ... canister mounting stay, 28a ... fitting projection, 30 ... crankcase, 31 ... crankshaft, 32 ... cylinder portion, 50 ... battery case, 51 ... recessed portion, 61 ... intake pipe, 61a ... Side wall (outer wall of downstream side intake passage), 61b ... support boss, 61c ... bolt, 61d ... valve mounting stay ("stay" in the present invention), 61e ... fitting projection, 62 ... vaporizer, 63 ... connecting tube, 64 ... Air cleaner case 65 ... Throttle valve, 68 ... Return opening, 68a ... Axial hole, 68b ... Communication hole, 71 ... Rubber band, 72 ... Fitting through hole, 73 ... Fixing projection, 82 ... Breaser tube, 91 ... Charge tube, 92 ... return purge pipe, 92c ... reverse U-shaped part, 93 ... new air introduction pipe, 94 ... drain pipe, 95 ... protective cover, 96 ... fitting through hole, 97 ... fixed projection, 100 ... evaporated fuel treatment device

Claims (5)

  Evaporative fuel treatment of a saddle-ride type vehicle (1) in which a power unit (5) having a cylinder portion (32) of an internal combustion engine (3) is disposed below a fuel tank (8) with respect to a crankcase (30) In the apparatus (100), an intake passage (6) including a carburetor (62) is disposed behind the cylinder part (32), and a canister (9) connected to the fuel tank (8) is connected to the intake air. A return purge pipe (92) from the canister (9) is disposed between the passage (6) and the crankcase (30) and in the vicinity of the lower portion of the carburetor (62), and the intake passage (6) In the side space of the carburetor (62), it extends upward from the vicinity of the lower portion of the carburetor (62), and then forms a reverse U-shaped portion (92c) to bypass and connect to the intake passage (6). Evaporative fuel processing device for saddle riding type vehicles.   A return opening (68) to which the return purge pipe (92) from the canister (9) is connected to the intake passage (6) is a valve opening / closing on the upstream side of the throttle valve (65) of the carburetor (62). A purge fuel gas from the canister (9) to the internal combustion engine (3) is supplied to the return purge pipe (92) according to the negative pressure on the return opening (68) side. The evaporative fuel processing device for a saddle type vehicle according to claim 1, further comprising a negative pressure limiting valve (7) for limiting the pressure.   A return opening (68) of the vaporizer (62) to which the return purge pipe (92) is connected is located at a lower edge (6Bb) of the intake passage (6) in a side view, and the return purge pipe The saddle type of claim 2, wherein an upper end of the inverted U-shaped portion (92c) of (92) is located above the upper edge (6Ca) of the intake passage (6) in a side view. Evaporative fuel processing device for vehicles.   The negative pressure limiting valve (7) is attached to a support boss (61b) provided on an outer wall (61a) of the intake passage (6) via a stay (61d). The evaporative fuel processing apparatus of the saddle riding type vehicle as described.   The evaporative fuel processing device for a saddle-ride type vehicle according to claim 4, wherein the canister (9) is covered with a protective cover (95).

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