JP2005248887A - Arrangement structure for secondary air supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To arrange a secondary air supply device at a position where the same is hardly affected by heat of an engine while shortening pipe of the secondary air supply device and to arrange the same at a position where the same can not be observed easily from an outside. <P>SOLUTION: A fuel tank 6 and a seat 7 are arranged in front and rear above an air cooled engine 5 and the secondary air supply device 15 for exhaust emission control is arranged in a space 18 above a cylinder. The space 18 above the cylinder is formed by a cylinder head 10, a bottom part rear side section 6a of the fuel tank and a bottom part front section 7a of the seat 7. The bottom part rear side section 6a inclines downward to front and the bottom part front side section 7a inclines upward to front. A cooling fan 26 is arranged in front of the engine 5 and the secondary air supply device 15 is arranged behind the same. Cooling air of the cooling fan 26 is led to an inclined surface of the bottom part rear side section of a fuel tank and heads toward the secondary air supply device 15. The secondary air supply device 15 is cooled by the cooling air and is hardly affected by heat of the engine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an advantageous arrangement structure of a secondary air supply device in a saddle-ride type vehicle such as a four-wheel buggy.

  In some motorcycles, a saddle-ride type vehicle in which a fuel tank and a saddle-ride type seat are arranged at the front and rear of an engine is provided with a secondary air supply device for exhaust purification. As an example of the arrangement structure of the secondary air supply device, a structure in which the secondary air supply device is attached to a down frame arranged forward of the engine and is connected to the exhaust port of the engine with a short pipe is known. (See Patent Document 1).

JP 2000-204939 A

By the way, it is desirable for the secondary air supply device to reduce the loss due to ventilation resistance by shortening the piping, but in order to improve the supply efficiency of the secondary air, it is arranged to be less susceptible to the heat effect of the engine It is also important to do. In particular, in a form in which the periphery of the engine is covered with a vehicle body cover like a four-wheel buggy car, it is difficult to arrange such that a cooling by running wind can be expected like a motorcycle.
In addition, from the viewpoint of improving the appearance of the vehicle body, it is also desired to arrange the secondary air supply device in a place where the appearance is not as difficult as possible. Therefore, the present invention aims to realize these requirements.

In order to solve the above-described problem, the arrangement structure of the secondary air supply device according to claim 1 is arranged such that a fuel tank and a saddle-ride type seat are arranged at the front and back of the engine, and the secondary air supply device for exhaust gas purification is provided in the engine. In the vehicle placed near the cylinder,
The secondary air supply device is arranged in a space above the cylinder formed above the engine and below the front side portion of the bottom of the saddle-ride type seat.

  A second aspect of the present invention is the method according to the first aspect, wherein the upper space above the cylinder is covered with a bottom rear side portion of the fuel tank and a bottom front side portion of the saddle-ride type seat located behind the fuel tank. The bottom rear side part is characterized in that the front lower part has a slope shape.

  A third aspect of the present invention according to the first aspect is characterized in that the secondary air supply device is located behind an engine cooling fan disposed in front of the engine.

  According to the first aspect, the secondary air supply device is separated from the engine and disposed in the secondary air supply device arrangement space above the engine, and the secondary air supply device arrangement space is inclined upward. Since it is formed by using the lower part of the front side of the saddle-ride type seat, it is possible to secure a space for arranging the secondary air supply device and to make it difficult to be affected by the heat of the engine, and to be arranged in the vicinity of the engine. Can be shortened. In addition, it is easy to make the arrangement difficult to be seen.

  According to the second aspect of the present invention, the upper part of the space where the secondary air supply device is disposed is formed by the bottom rear portion of the fuel tank inclined forward and the bottom front portion of the saddle type seat inclined upward. The space above the cylinder, which is the installation space for the secondary air supply device, has a substantially mountain shape when viewed from the side, and can form a relatively large space. In addition, since the air is likely to flow obliquely upward along the bottom of the fuel tank located on the space where the secondary air supply device is disposed, the thermal influence on the secondary air supply device can be further reduced.

  According to the third aspect, since the secondary air supply device is located behind the engine cooling fan provided in front of the engine, the secondary air supply device can be cooled using the cooling air generated by the engine cooling fan. Therefore, the thermal effect can be further reduced. In addition, since the secondary air supply device is not disposed between the engine cooling fan and the engine, the cooling efficiency of the engine can be prevented from being lowered.

  Hereinafter, an embodiment applied to a four-wheel buggy that is a saddle-ride type vehicle will be described with reference to the drawings. FIG. 1 shows a side view of the four-wheel buggy. Reference numeral 1 denotes a front wheel and 2 denotes a rear wheel, which are arranged on the left and right sides of the body frame 3 in pairs. The vehicle body frame 3 is provided with an upper frame 3a and a lower frame 3b at the top and bottom, and extends in the front-rear direction in a pair of left and right, and the lower frame 3b is connected to the upper frame 3a in the front-rear direction. 4 is a steering shaft, 5 is an engine, 6 is a fuel tank, 7 is a saddle type seat, and 8 is an air cleaner.

  The engine 5 is a four-cycle air-cooled engine, and is a vertical type in which the crankshaft 9 is disposed in the front-rear direction. The cylinder head 10 is provided with a cylinder head cover 11 having a built-in valve mechanism in the upper part, an intake passage is opened on the rear side, and a throttle body 12 forming a fuel injection device is connected to the opening of the intake passage. ing. The throttle body 12 is connected to a purified air discharge portion of an air cleaner 8 disposed behind the throttle body 12. The air cleaner 8 is supported by the upper frame 3a. The same applies to the fuel tank 6 and the seat 7.

  The throttle body 12 is integrated with an ECU to perform ignition control and fuel injection control. Clean air is supplied to the throttle body 12 from the clean side of the air cleaner 8 and fuel is supplied from the fuel feed tube 13 to supply the air-fuel mixture to the intake passage of the cylinder head 10.

  Above the cylinder head 10, a secondary air supply device 15 connected to the front surface of the air cleaner 8 by a secondary air suction hose 14 is disposed. The secondary air supply device 15 is a valve device for secondary air that is compactly configured by integrating a flow control valve for secondary air and a reed valve that is an on-off valve.

  An exhaust port is provided on the front side of the cylinder head 10, and the front end of the exhaust pipe 20 is connected to the exhaust port. The exhaust pipe 20 protrudes forward of the cylinder head 10, then bends in a substantially U shape, crosses the side of the cylinder head 10, extends rearward, and is connected to the muffler 21.

  The muffler 21 overlaps the upper side of the rear wheel 2 in a side view and is supported on the rear portion of the upper frame 3a. A catalyst is provided in the muffler 21 to purify the exhaust gas, and when secondary air is supplied to the exhaust port by the secondary air supply device, oxygen in the exhaust gas increases, thereby improving the purification efficiency by the catalyst. It is supposed to be.

  The rear end portion of the exhaust pipe 20 crosses the substantially vertical center of the side surface of the air cleaner 8, and the rear end portion of the exhaust pipe 20, the front end portion of the muffler 21, and the connection portion are located in the vicinity of the rear end of the air cleaner 8. Reference numeral 5a denotes a crankcase, and an intermediate portion of the exhaust pipe 20 is disposed substantially parallel to the upper surface thereof.

  As shown in FIG. 2, the secondary air supply device 15 is operated by the negative intake pressure of the engine via the negative pressure pipe 16, and uses the purified air supplied from the clean side of the air cleaner 8 as the secondary air to send out the secondary air. The pipe 17 is sent to the exhaust port of the cylinder head 10 to purify the exhaust.

  The secondary air supply device 15 is connected to the intake passage of the cylinder head 10 by a negative pressure pipe 16, and the flow rate control valve has a secondary air amount from the secondary air intake hose 14 according to the intake negative pressure of the intake port 11. The reed valve opens and closes at a predetermined negative pressure level. When the reed valve is opened, the secondary air whose flow rate is controlled is supplied to the exhaust port via the secondary air delivery pipe 17.

The position of the secondary air supply device 15 is arranged in a cylinder upper space 18 surrounded by a bottom rear side portion 6 a of the fuel tank 6, a bottom front side portion 7 a of the seat 7 and an upper portion of the cylinder head 10. It is supported by being overlapped on a boss 22a formed at the rear end of a separate bottom plate 22 extending rearward from the bottom and bolted.
The bottom rear side portion 6a of the fuel tank 6 is inclined rearward and obliquely upward, the bottom front side portion 7a of the seat 7 is inclined forwardly forwardly, and the cylinder upper space 18 has a substantially mountain shape in a side view shown in the drawing. The rear end portion of the fuel tank 6 is an extended portion 6 b that protrudes substantially horizontally at a position above the bottom plate 22 and reaches the vicinity of the secondary air supply device 15.

  The front portion of the secondary air suction hose 14 is disposed obliquely rearward along the inclination of the bottom front portion 7a of the seat 7, the middle portion bends substantially horizontally on the throttle body 12, and the rear portion is the front surface of the air cleaner 8. And communicates with the clean side of the air cleaner 8. Reference numeral 19 denotes a snorkel. The front end suction port is located above the rear end of the fuel tank 6 and at the front end of the seat 7, and is disposed obliquely rearward along the bottom front side portion 7 a and connected to the dirty side of the air cleaner 8.

  A fuel pump 23 is separated from the fuel tank 6 and disposed in front of the engine 5 and below the fuel tank 6. The fuel pump 23 is connected to the lowermost part 6d having a substantially funnel shape in a side view protruding downward at the center of the bottom of the fuel tank 6 by a fuel tube 24, and through a fuel filter 35 provided in the middle of the fuel tube 24, The fuel is supplied from the fuel tank 6 to the fuel pump 23 by free fall. The fuel pressurized by the fuel pump 23 is supplied to the throttle body 12 through the fuel feed tube 13. The lowermost portion 6d is positioned at a height that is substantially the same as the upper portion of the cylinder head 10 that overlaps the cylinder head cover 11 in the front-rear direction, and the upper portion of the fuel pump 23 is positioned at a height that is approximately the same as the exhaust pipe 20. As a result, the fuel tube 24 is a short one arranged in the vertical direction.

  The fuel feed tube 13 extends upward from the fuel pump 23 and then bends substantially horizontally to the rear. The fuel feed tube 13 extends rearward while overlapping a part of the lowermost part 6d in a side view, and is substantially U-shaped in a side view above the cylinder head 10. It passes in a shape, intersects with the negative pressure pipe 16, and is connected so that the rear end is connected to the throttle body 12.

  The fuel pump 23 has a substantially cylindrical shape in which the sub fuel tanks are integrated, and is arranged with the longitudinal direction facing up and down. Although the fuel tank 6 is made of a synthetic resin that is difficult to integrate the fuel pump 23, the fuel pump 23 can be separated from the fuel tank 6 in this way. From the upper part of the fuel pump 23, a return tube 25 dedicated to vapor return extends substantially vertically upward, and its upper end is mounted in a recess 6e provided in the upper part of the fuel tank 6 and is above the liquid level 6c when full. It communicates with the space.

  Reference numeral 26 denotes a cooling fan for cooling the engine, and the fuel pump 23 is disposed on the rear side of the cooling fan 26 in a side view. The cooling fan 26 forcibly air-cools the oil cooler 27 disposed in front of the cooling fan 26 and the rear engine 5. The oil cooler 27 circulates engine oil in the crankcase 5a.

  The cooling fan 26 is located in front of and lower than the secondary air supply device 15, and the fuel tank 6 exists between the cooling fan 26 and the secondary air supply device 15. A part of the cooling air sent to the rear of the vehicle body toward the vehicle is guided by the bottom rear side portion 6a of the fuel tank 6 that rises obliquely rearward in the cylinder upper space 18 and flows to the vicinity of the secondary air supply device 15. It is like that.

  FIG. 3 is a plan view of a four-wheel buggy vehicle, and FIG. 4 is an enlarged plan view of a main part. In these drawings, the secondary air supply device 15 is located substantially in the vicinity of the vehicle body center C. The negative pressure pipe 16 and the air cleaner 8 are also located substantially on the center of the vehicle body. The fuel pump 23 is arranged on the right side of the vehicle body, and the exhaust pipe 20 is piped on the left side of the cylinder head 10, whereas the fuel pump 23 is arranged on the side opposite to the pipe side and away from the exhaust pipe 20. The arrangement is less susceptible to heat. The return tube 25 is piped up and down in a state of entering a recessed groove 6f formed on the side surface of the fuel tank 6 (FIG. 4). In FIG. 3, reference numeral 36 denotes a headlight, 37 denotes a handle bar, and 38 denotes a handle grip.

  FIG. 5 is a view showing the front of the vehicle body. As the cylinder head 10c is tilted toward the left side of the vehicle body, the entire cylinder head 10 is tilted upward from the left side of the vehicle body. The cylinder head cover 11 is biased to the right side of the vehicle body at the upper part of the cylinder head 10, and the cylinder head cover 11 and the secondary air supply device 15 overlap the bottom rear side of the fuel tank 6 as viewed from the front.

  The exhaust port 30 is located slightly shifted to the right side of the vehicle body from the vehicle body center C, from which the exhaust pipe 20 extends obliquely downward toward the left side of the vehicle body, and extends rearward substantially horizontally on the side of the cylinder head 10. . The fuel pump 23 is disposed on the inclined side of the cylinder head 10 and on the right side of the vehicle body opposite to the arrangement side of the intermediate portion of the exhaust pipe 20, and substantially outside the front portion 3c of the vehicle body frame 3 in the front view shown in the drawing. Arranged in parallel and attached to a bracket 34 extending downward from the upper frame 3a.

The return tube 25 extends substantially vertically upward from the fuel pump 23, bends to the right side of the vehicle body once in the vicinity of the bottom of the fuel tank 6, passes through a recess formed in the side surface of the fuel tank 6, and is relatively less bent The upper end is bent inward of the vehicle body and overlaps the upper part of the fuel tank 6.
Reference numeral 31 denotes a front cover that covers an upper portion of the front portion of the vehicle body including the fuel tank 6, and 32 denotes a front fender integrated with the front cover 31.

  FIG. 6 is a view showing the arrangement of the engine 5, the secondary air supply device 15, and the fuel pump 23 from the front of the vehicle body. The left side of the cylinder head cover 11 is a stepped portion upper space 10a in which a step is formed and the upper surface of the cylinder head 10 is exposed. This step portion upper space 10a is a part of the cylinder upper space 18, and the secondary air supply device 15 is disposed in this space.

The secondary air suction pipe 14 extends downward from the inner side surface of the secondary air supply device 15 in the space above the step 10 a.
The negative pressure pipe 16 is directed substantially horizontally from the bottom of the secondary air supply device 15 toward the center of the vehicle body, bends downward substantially at the center of the vehicle body, overlaps the back side of the cylinder head cover 11, and is located on the opposite side of the exhaust port 30. Connected to the aisle.

  The secondary air delivery pipe 17 exits from the outer surface of the secondary air supply device 15 substantially horizontally to the side, then bends in a substantially U shape and returns to a position overlapping the secondary air supply device 15 in front view. It bends further downward and extends downward. The lower end portion enters the cylinder head 10 from the upper surface exposed portion 10 b of the cylinder head 10 and is connected to the vicinity of the exhaust port 30.

  The fuel pump 23 is located in front of the front right side of the cylinder head 10, and the fuel feed tube 13 connected to the discharge side joint 33 extends upward in front of the front of the cylinder head 10 and bends above the cylinder head cover 11. It extends rearward, bends downward on the back side of the cylinder head cover 11, and is connected to the throttle body 12. Reference numeral 34 denotes a support bracket for the fuel pump 23.

  Next, the operation of this embodiment will be described. As shown in FIGS. 1 and 2, the secondary air supply device 15 is separated from the engine 5 and disposed in the cylinder upper space 18 above the engine 5, and the cylinder upper space 18 is formed by the seat 7 inclined upward. Since it is formed using the lower portion of the bottom front side portion 7a, a space for arranging the secondary air supply device 15 can be secured. In addition, the piping can be shortened by being less likely to be affected by the heat of the engine 5 and disposed in the vicinity of the engine. In addition, it is possible to easily arrange the cylinder upper space 18 by covering the cylinder upper space 18 with a vehicle body cover continuous with the front cover 31.

Further, the upper part of the cylinder upper space 18 is formed in a substantially mountain shape by the bottom rear side part 6a of the fuel tank 6 inclined forward and the bottom front side part 7a of the seat 7 inclined forwardly upward. 18 has a substantially mountain shape in side view, and can form a relatively large space. For this reason, the air flow in the cylinder upper space 18 is likely to occur, the cooling efficiency of the secondary air supply device 15 is improved, and the thermal influence from the engine 5 can be further reduced. In particular, the four-wheel buggy car is surrounded by a body cover and cannot be expected to be cooled directly by the driving wind.
Despite such a structure, it can be made less susceptible to thermal effects.

  In addition, since the bottom rear side portion 6a of the fuel tank 6 has a slope inclined forward and downward, the air easily rises diagonally along the bottom of the fuel tank located on the cylinder upper space 18, so that the air Can be guided to the secondary air supply device 15, and the cooling efficiency of the secondary air supply device 15 can be improved. In addition, since the rear end portion of the fuel tank 6 is the extended portion 6 b that reaches the vicinity of the secondary air supply device 15, the air can be more reliably guided to the secondary air supply device 15.

  Furthermore, since the secondary air supply device 15 is located behind the cooling fan 26 provided in front of the engine 5, the secondary air supply device 15 can be cooled using the cooling air generated by the cooling fan 26. Further, the thermal effect can be reduced. At this time, the bottom rear portion 6a of the fuel tank 6 can guide cooling air. In addition, since the secondary air supply device 15 is not disposed between the cooling fan 26 and the engine 5, the cooling efficiency of the engine 5 can be prevented from being lowered.

The present invention is not limited to the above-described embodiment, and various modifications and applications are possible within the principle of the invention. For example, the present invention can be applied to other types of saddle riding type vehicles such as motorcycles. The engine may be water-cooled. In this case, the cooling fan 26 is used for cooling the radiator.

Side view of a 4-wheel buggy car The side view which expanded the above-mentioned principal part Top view of 4-wheel buggy car The top view which expanded the above-mentioned principal part The figure which shows the principal part from the vehicle body front The figure which shows arrangement of an engine and a secondary air supply device etc.

Explanation of symbols

1: front wheel, 2: rear wheel, 3: body frame, 5: engine, 6: fuel tank, 7: seat, 8: air cleaner, 10: cylinder head, 12: throttle body, 13: fuel feed tube, 15: Secondary air supply device, 18: space above cylinder, 20: exhaust pipe, 23: fuel pump, 24: fuel tube, 25: return tube, 26: cooling fan

Claims (3)

In a vehicle in which a fuel tank and a saddle-ride type seat are arranged at the front and back of the engine, and a secondary air supply device for exhaust purification is arranged in the vicinity of the engine cylinder,
An arrangement structure of the secondary air supply device, wherein the secondary air supply device is arranged in a space above the cylinder formed above the engine and below the front portion of the bottom portion of the saddle-ride type seat. The upper space above the cylinder is covered with a bottom rear side portion of the fuel tank and a bottom front side portion of the saddle-ride type seat located behind the fuel tank, and the bottom rear side portion of the fuel tank has a front and lower slope. The arrangement structure of the secondary air supply device according to claim 1, wherein the arrangement structure is a shape. The arrangement structure of the secondary air supply device according to claim 1, wherein the secondary air supply device is positioned behind an engine cooling fan arranged in front of the engine.

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