JP4468861B2 - Vehicle exhaust system - Google Patents

Description

  The present invention relates to an exhaust device for a vehicle including a catalytic converter.

In general, an exhaust device for a motorcycle in which a muffler is connected to an exhaust pipe extending from an engine is known (see, for example, Patent Document 1). In this type of vehicle exhaust system, there has been proposed a type in which a rear portion of an exhaust pipe is introduced into a muffler, and the rear portion of the exhaust pipe is expanded rearward in order to improve engine performance. In the above-described conventional exhaust system, the catalytic converter includes a catalyst chamber, an exhaust gas introduction pipe to the catalyst chamber is connected to one end side of the catalyst chamber, and the exhaust pipe is connected to the other end side of the catalyst chamber. It is common to do.
JP-A-6-10659

However, if the catalytic converter is connected in series to the exhaust pipe extending rearward, the exhaust pipe becomes longer in the front and rear, making it difficult to fit in a compact manner.
Also, with this configuration, the catalytic converter layout cannot be diversified. For example, when connecting a catalytic converter in the middle of an exhaust pipe line extending in one direction and orthogonal to the extending direction of the exhaust pipe, in the conventional configuration, the exhaust pipe of the catalytic converter is in one direction. It is led out to the other end side of the catalytic converter away from the line of the extending exhaust pipe. In this case, the exhaust pipe of the catalytic converter must be pulled back onto the exhaust pipe line extending in one direction. For this purpose, the exhaust pipe must be routed in a complicated shape such as a substantially U shape. I will have to.
In addition, in the case where a catalyst is provided in the muffler as in the past, activation of the catalyst is delayed in a cold state immediately after the start of traveling.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle exhaust system that can solve the above-described problems of the prior art, diversify the layout of a catalytic converter, and promote catalyst activation in a cold state. is there.

The present invention relates to a vehicle exhaust system in which a muffler is connected to an exhaust pipe extending from an engine, and the exhaust pipe extends in the front-rear direction of the vehicle at a position below the engine and deviated to one side of the engine in the left-right direction of the vehicle. A catalytic converter extending in the vehicle lateral direction from the exhaust pipe so as to intersect with the extending direction of the exhaust pipe in the middle of the exhaust pipe , the catalytic converter including an exhaust gas introduction pipe into the catalyst chamber And a discharge pipe are collectively arranged on one end side of the catalyst chamber, and the catalyst chamber includes a first catalyst chamber communicating with the introduction pipe and a second catalyst chamber communicating with the discharge pipe, The first and second catalyst chambers communicate with each other at the other end of the catalyst chamber, and the exhaust gas that has passed through the introduction pipe passes through the first catalyst chamber and then reverses at the other end, and then the second catalyst chamber. Pass through to the discharge pipe Converter is formed, the catalytic converter, characterized in that it is arranged inside in the vehicle width direction directly below and the engine of the engine.

In the present invention, since the exhaust gas introduction pipe and the exhaust pipe are collectively arranged on one end side of the catalyst chamber, for example, even when the catalytic converter is connected perpendicularly to the extending direction of the exhaust pipe, The introduction pipe and the discharge pipe of the catalytic converter can be easily connected to the exhaust pipe without drawing the exhaust pipe into a complicated shape.
Therefore, the ease of connecting pipes is improved and the layout of the catalyst is diversified. In addition, when the catalytic converter is built in the muffler, the muffler diameter can be suppressed to substantially the same as that of the conventional muffler, and the increase in size of the muffler is suppressed.
In the catalytic converter, the first catalyst chamber may be disposed in front of the second catalyst chamber in the longitudinal direction of the vehicle.
The catalytic converter includes an outer cylinder and an inner cylinder, the first catalyst chamber is surrounded by the inner cylinder and includes the first catalyst body, and the second catalyst chamber is surrounded by the inner cylinder and the outer cylinder. Each catalyst body is formed by overlapping and winding a flat plate and a corrugated plate, between the flat plate and the corrugated plate of each catalyst body, between the catalyst body and the inner cylinder, and between the catalyst body and the outer cylinder The joining region located on the outlet side in the exhaust gas discharge direction in the axial direction of each catalyst body may be brazed.

Further, the catalytic converter has a catalyst body of the honeycomb type, after the exhaust gas to the catalyst body through the inlet tube, has passed through the first catalyst chamber defined by a portion of the porous honeycomb type, further honeycomb You may provide the structure which passes along the said 2nd catalyst chamber formed by the porosity of the other part of a type | mold, and reaches a discharge pipe.
Furthermore, the catalytic converter may include a partition that divides a space into an inlet side to the catalyst body and an outlet side from the catalyst body on one end side of the catalyst chamber. The honeycomb-type catalyst body is formed by winding a flat plate and a corrugated plate, and the flat plate and the corrugated plate in a part of the pores are joined to each other in the axial direction of the part of the porous gas and located in the exhaust gas discharge direction. Only the region may be brazed, and a joining region located on the outlet side in the exhaust gas discharge direction may be brazed between the flat plate and the corrugated plate in the other porous portion. Further, the porous part of the honeycomb type or a part of the other part may be a porous part of the central part of the honeycomb type, and the other part or part of the porous part of the honeycomb type may be a porous part of the outer periphery of the honeycomb type. .

  Using a honeycomb-type catalyst body, the exhaust gas to the catalyst body that has passed through the introduction pipe passes through the porous part of the honeycomb type and then passes through the other part of the honeycomb type to reach the exhaust pipe Therefore, no partition is required between a part of the pores and the other part of the pores, and the exhaust gas reciprocating passage is formed with a simple configuration.

The catalytic converter connected to the exhaust pipe may be disposed directly under the engine. According to this configuration, it is possible to arrange a catalytic converter using a so-called dead zone directly under the engine, so that the arrangement space can be made efficient and the weight balance of the vehicle can be optimized. Further, since the catalytic converter is disposed in the vicinity of the engine, the activation of the catalyst is promoted by the latest heat of the engine even in the cold state after the start of traveling.
Furthermore, the catalytic converter may be placed in front of the driver's step. According to this, the space in front of the driver's step is effectively used, and the weight balance of the vehicle is optimized.

You may arrange | position a catalytic converter inside the vehicle width direction of a leg shield. Inside the leg shield in the vehicle width direction, the engine heat is easily trapped. In this configuration, the temperature on the inner side in the vehicle width direction of the leg shield rises within a short time after the engine is started and before the start of running, and is heated by this heat to promote the activation of the catalytic converter. The
Further, the space on the inner side in the vehicle width direction of the leg shield is effectively used, and the weight balance of the vehicle is optimized. The exhaust pipe protector may be disposed between the output discharge the introduction tube of the catalytic converter tubes. In this configuration, the open side of the emissions tube, because it is covered by the protector, appearance, improved aesthetics.

In the present invention, the exhaust gas introduction pipe and the exhaust pipe into the catalyst chamber are arranged together on one end side of the catalyst chamber, so that, for example, a case where the catalytic converter is connected perpendicularly to the direction in which the exhaust pipe extends is used. However, without introducing the exhaust pipe into a complicated shape, the introduction pipe and exhaust pipe of the catalytic converter can be easily connected to the exhaust pipe, thus improving the ease of connecting the piping and the layout of the catalytic converter. Diversification.
In addition, when the catalytic converter is built in the muffler, the muffler diameter can be suppressed to substantially the same as that of the conventional muffler, and the increase in size of the muffler is suppressed.
Further, the catalytic converter can be easily installed in a narrow space near the engine such as a motorcycle. According to this, even in the cold state immediately after the start of traveling, the activation of the catalyst is promoted by the latest engine heat.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
In FIG. 1, reference numeral 1 denotes a motorcycle (vehicle). The motorcycle 1 is configured by covering a front portion of a press frame 7 with a cover 2. A front fork 5 that supports the front wheels 4 is supported on the head tube 3 at the front of the press frame.

  An engine 6 is mounted on the lower middle part of the cover 2, and a fuel tank or the like (not shown) is provided on the inner side behind the cover 2. A sheet 8 is extended above. A rear fork 10 that supports the rear wheel 9 is swingably supported below the press frame 7, and a rear cushion unit 11 is interposed between the rear fork 10 and the rear portion of the frame. A handle 12 is attached to the upper part of the steering stem extending on the head tube 3, a headlight unit 13 is attached to the center of the handle 12, and blinker lamps 14 are provided on the left and right of the handle 12. It is attached.

  Leg shields 15 constituting the front part of the cover 2 are provided on the left and right sides of the front part of the motorcycle 1, and the leg shields 15 are integrally enclosed from the driver's feet right and left to the upper side of the head tube 3. Is formed. An intermediate portion of the leg shield 15 is curved backward so as to surround the rear portion of the head tube 3, and a vertical hook-shaped top cover 16 is disposed at the front portion of the head tube 3 positioned there. 16 is fixed to an intermediate portion of the leg shield 15.

In this embodiment, the engine 6 is supported by the lower part 7a of the press frame 7 via the two hanger bolts 21, as shown in FIG.
One end 23 a of an exhaust pipe 23 is connected to the exhaust port 6 b of the cylinder head 6 a of the engine 6 via a connecting flange 22. The exhaust pipe 23 is led out below the engine 6, and is connected to the catalytic converter 30 through a lead-out portion 23 b that leads out to the rear of the vehicle body in the vicinity immediately below the engine 6, and a rear end portion 23 c of the exhaust pipe 23. And it is connected to the muffler 25 as a so-called silencer.

The catalytic converter 30 constitutes a part of the exhaust pipe 23 and extends in the left-right direction of the vehicle so that its axis L is orthogonal to the line of the exhaust pipe 23 extending in approximately one direction. Further, the catalytic converter 30 is disposed immediately below the engine 6 so as to be substantially within the width of the engine 6.
In this catalyst layout, since the axis L of the catalytic converter 30 is arranged so as to be substantially orthogonal to the line of the exhaust pipe 23 extending in approximately one direction, the axis L of the catalytic converter 30 coincides with the same direction as this line. The catalytic converter 30 having a large capacity and a relatively large size in the longitudinal direction is disposed in the front and rear of the vehicle within a short distance from the one end 23a to the rear end 23c of the exhaust pipe 23 as compared with the one arranged in the above manner. A compact arrangement can be achieved without increasing the directional dimension.

As shown in FIG. 4, the catalytic converter 30 includes a substantially cylindrical converter body 51 whose both ends are closed, and a catalyst body 53 formed in the converter body 51. On the one end 51 a side of the cylindrical converter body 51, an exhaust gas introduction pipe 55 to the catalyst body 53 and an exhaust gas exhaust pipe 57 after passing through the catalyst body 53 are arranged together.
The catalyst body 53 includes a first catalyst chamber 53a (indicated by broken line hatching) that communicates with the introduction pipe 55 via the communication pipe 61, and a second catalyst chamber 53b that communicates with the discharge pipe 57. As shown in FIG. 5, the first and second catalyst chambers 53a and 53b may be set so that their cross-sectional areas are substantially equal, or the ratios thereof may be arbitrarily changed from the noise reduction efficiency.
A first catalyst chamber 53a is located inside the catalyst body 53, and as shown in FIG. 4, its inlet A communicates with the introduction pipe 55 via the communication pipe 61, and its outlet B is the converter body. 51 communicates with the reversing chamber 63 on the other end 51b side.
The reversing chamber 63 communicates with the inlet C of the second catalyst chamber 53 b disposed outside the catalyst body 53, and the outlet D communicates with the collecting chamber 65 on the one end 51 a side of the converter body 51. A discharge pipe 57 communicates with 65.

The catalyst body 53 is composed of a porous honeycomb structure coated with platinum, palladium, rhodium or the like.
This constitutes a honeycomb type three-way catalyst, and the exhaust gas which has entered the inlet A of the first catalyst chamber 53a through the introduction pipe 55 and the communication pipe 61 described above is oxidized with hydrocarbons in the exhaust gas. After carbon and nitrogen oxides are removed by oxidation and reduction reactions, they reach the reversal chamber 63 from the outlet B and enter the inlet C of the second catalyst chamber 53b from here, where they again become the hydrocarbons in the exhaust gas. Carbon oxide and nitrogen oxide are removed by oxidation and reduction reaction, reach the collecting chamber 65 from the outlet D, and are discharged from the exhaust pipe 57 to the muffler 25.
In the above configuration, since all the pores of the honeycomb penetrate from one end of the catalyst body 53 to the other end, when the communication pipe 61 is connected to a part (center side) of one end of the catalyst body 53, a part of The exhaust gas flows in one direction as a porous communication pipe (first catalyst chamber 53a) as it is, and the exhaust gas reversed in the reversing chamber 63 at the other end of the catalyst body 53 is now another part of the porous pores of the honeycomb ( The second catalyst chamber 53b) flows in the reverse direction. That is, the function of one honeycomb catalyst body 53 also serves as a two-way communication pipe.
Further, since the catalyst body 53 is a honeycomb type three-way catalyst composed of an assembly of originally partitioned passages, no partition is required between the first and second catalyst chambers 53a and 53b, and the configuration is simple. Since exhaust gas is reciprocated in the passage of the single catalyst body 53, efficient purification becomes possible, and activation becomes easy.

The three-way catalyst generally has a small ability to react and purify hydrocarbons until reaching the activation temperature (about 300 ° C.), and when the temperature is reached, the ability becomes high.
In this configuration, since the catalytic converter 30 is disposed in the vicinity immediately below the engine 6, the heat of the engine 6 makes it easy for the temperature of the three-way catalyst to reach the activation temperature. Even so, the heat is received from the engine 6 and the temperature is raised within a very short time, and the three-way catalyst is activated quickly.

In this configuration, since the catalytic converter 30 is provided in the middle of the exhaust pipe 23 described above, it is not necessary to provide a large capacity catalyst in the muffler 25.
Therefore, the muffler 25 can be downsized as compared with the case where a large capacity catalyst is provided in the muffler 25. Further, since the catalytic converter 30 is disposed substantially orthogonal to the direction in which the exhaust pipe 23 extends, the catalyst converter 30 has a sufficient capacity of the catalyst converter 30 without increasing the size in the front-rear direction of the motorcycle. It can be easily placed compactly in a narrow space near the engine.

In this configuration, as shown in FIG. 3, since the catalytic converter 30 is arranged in a so-called dead zone, which is directly under the engine 6, it is possible to effectively use the space and to arrange it without increasing the overall width of the vehicle. In addition, since the catalytic converter 30 is difficult to appear on the appearance, the degree of freedom in designing the vehicle body can be ensured.
Further, since the catalytic converter 30 is disposed directly under the engine 6, the position of the center of gravity is lowered, and the vehicle weight balance is optimized.
In this case, an under guard 39 is provided directly below the catalytic converter 30 so as to cover almost the entire region from below. The under guard 39 is fixed to the outer wall of the catalytic converter 30 through a bolt 39a. The under guard 39 is formed with a receiving groove 39b for receiving the head of the bolt 39a. The head of the bolt 39a does not protrude from the lower surface of the under guard 39.
In this configuration, the catalytic converter 30 is protected by the under guard 39, and the catalyst is more activated by the heat retaining effect.

As shown in FIG. 2, a step shaft 41 is fixed to the lower surface of the engine 6 with screws, and driver steps 43 are disposed at both ends of the step shaft 41.
In this configuration, the catalytic converter 30 is arranged in front of the driver's step 43. According to this, the driver's foot contact is avoided, the influence on the driver's heat is suppressed to be relatively small, the space in front of the step 43 is effectively used, and the weight balance of the vehicle is optimized. Is planned.

  Further, the catalytic converter 30 is disposed on the inner side in the vehicle width direction of the leg shield 15 described above. On the inner side in the vehicle width direction of the leg shield 15, the heat of the engine 6 is easily trapped when the vehicle stops. Therefore, the air temperature inside the leg shield 15 in the vehicle width direction rises within a relatively short time after the engine 6 is started, and thereby the catalytic converter 30 is more easily activated. Further, the space on the inner side in the vehicle width direction of the leg shield 15 is effectively used, and the weight balance of the vehicle is optimized.

In this configuration, the exhaust gas introduction pipe 55 and the exhaust pipe 57 are arranged together on the one end 51a side of the cylindrical converter main body 51. Therefore, as shown in FIG. 57, a discontinuous portion of the exhaust pipe 23 appears, and an exhaust pipe protector 47 is disposed at the discontinuous portion so as to cover the discontinuous portion. The exhaust pipe protector 47 is fixed to a boss 23d through bolts 47a, and the bosses 23d are welded to the outer wall of the exhaust pipe 23, respectively. The exhaust pipe protector 47 is formed with a receiving groove 47b for receiving the head of the bolt 47a. The head of the bolt 47a does not protrude from the surface of the exhaust pipe protector 47.
In this configuration, since the discontinuous portion of the exhaust pipe 23 is covered with the exhaust pipe protector 47, the exhaust pipe 23 is protected and insulated, and the discontinuous portion of the exhaust pipe 23 is hidden in appearance. Therefore, it looks as if the exhaust pipe 23 is continuous from the outside of the vehicle, which improves the aesthetics and is preferable in terms of appearance.

The catalytic converter 30 is not limited to the above configuration example. For example, as shown in FIG. 6, the converter main body 151, a catalyst body (honeycomb body) 153 disposed in the main body 151, and the catalyst body 153 A partition wall 152 that partitions the inlet side and outlet side spaces J and K may be provided. A predetermined gap d may be provided between the partition wall 152 and the catalyst body 153 in consideration of the thermal expansion of the honeycomb body. In this case, d ≦ 5 mm is desirable. The catalyst body 153 may include first and second catalyst chambers 153a and 153b having substantially the same cross-sectional area, or the ratio may be arbitrarily changed in accordance with noise reduction efficiency.
In this case, the catalyst body 153 is composed of a honeycomb type three-way catalyst containing platinum, palladium, rhodium, and the like, and passes through the introduction pipe 155 and the inlet side space J from the porous portion of the honeycomb connected to the space J. The exhaust gas that has entered the inlet A of the first catalyst chamber 153a (the right half of the catalyst body 153 in FIG. 6) is produced by oxidizing and reducing hydrocarbons, carbon monoxide, and nitrogen oxide in the exhaust gas. After the removal, the outlet B leads to the reversal chamber 163, from which it enters the inlet C of the second catalyst chamber 153b (the left half portion of the catalyst body 153 in FIG. 6), where it again matches the hydrocarbons in the exhaust gas. Carbon oxide and nitrogen oxide are removed by oxidation and reduction reaction, and then discharged to the muffler 25 through the outlet D, the outlet side space K, and the discharge pipe 157.

  Further, as shown in FIG. 7, the catalytic converter 30 includes a converter main body 251, and in the converter main body 251, a first punching pipe 252 disposed along the inner peripheral wall of the main body, and an introduction pipe 255. The second punching pipe 254 disposed along the inner peripheral wall of the first and second punching pipes 254 may be disposed concentrically, and platinum, palladium, rhodium, etc. may be supported on the punching pipes. In this case, the space in which the first punching pipe 252 extends constitutes the first catalyst chamber 253a, and the space in which the second punching pipe 254 extends constitutes the second catalyst chamber 253b. The first and second catalyst chambers 253a and 253b are formed of a honeycomb type three-way catalyst, and the exhaust gas that has entered the first catalyst chamber 253a through the introduction pipe 255 is oxidized with hydrocarbons in the exhaust gas. After the carbon and nitrogen oxide are removed by oxidation and reduction reaction, the reversal space 263 is reached, from which it enters the second catalyst chamber 253b, where again the hydrocarbons, carbon monoxide and nitrogen oxides in the exhaust gas Is removed by oxidation and reduction reaction and discharged to the muffler 25 through the discharge pipe 257.

  The catalytic converter 30 has a cylindrical cross-sectional shape, but is not limited thereto, and may be, for example, a polygonal cylindrical shape. In particular, in a motorcycle, when it is disposed directly under the engine 6, it is desired to make the catalytic converter 30 thinner. In this case, for example, it may be a lunch box type thin rectangular tube or the like.

FIG. 8 shows another embodiment.
In this embodiment, the catalytic converter is disposed inside the muffler 325. The muffler 325 is a multi-chamber type muffler, and is divided into first, second partition walls 325a and 325b from the introduction pipe 355 side, and second, first, and third expansion chambers N and M. , O are formed in that order. And the catalytic converter 30 of this structure is arrange | positioned through the said 1st partition wall 325a through the said wall.
The catalytic converter 30 includes a cylindrical converter body 351 and a catalyst body 353 formed in the converter body 351. An exhaust gas introduction pipe 355 to the catalyst body 353 and an exhaust gas exhaust pipe 357 after passing through the catalyst body 353 are arranged together on the one end 351 a side of the cylindrical converter main body 351.

  The catalyst body 353 includes a first catalyst chamber 353a communicating with the introduction pipe 355 via the communication pipe 361, and a second catalyst chamber 353b communicating with the discharge pipe 357 via the second expansion chamber N. The first and second catalyst chambers 353a and 353b may be set so that their cross-sectional areas are substantially equal, or the ratio thereof may be arbitrarily changed from the noise reduction efficiency. A first catalyst chamber 353 a is located inside the catalyst body 353, its inlet A communicates with the introduction pipe 355 via the communication pipe 361, and its outlet B is on the other end 531 b side of the converter body 351. The reversing chamber 363 (first expansion chamber M) communicates with the reversing chamber 363. The inversion chamber 363 communicates with the inlet C of the second catalyst chamber 353b disposed outside the catalyst body 353, and the outlet D thereof is the collecting chamber 365 (second expansion chamber N) on the one end 351a side of the converter body 351. A discharge pipe 357 communicates with the collecting chamber 365. The discharge pipe 357 passes through the first and second partition walls 325a and 325b and communicates with the third expansion chamber O. The third expansion chamber O is connected to the outside through the exhaust pipe 371. Communicating with

The catalyst body 353 is composed of a honeycomb structure coated with platinum, palladium, rhodium or the like.
This constitutes a honeycomb type three-way catalyst, and the exhaust gas which has entered the inlet A of the first catalyst chamber 353a through the introduction pipe 355 and the communication pipe 361 described above and the hydrocarbons in the exhaust gas are oxidized. After carbon and nitrogen oxides are removed by oxidation and reduction reactions, they reach the reversal chamber 363 (first expansion chamber M) from the outlet B, enter the inlet C of the second catalyst chamber 353b from here, and exhaust again here. Hydrocarbon, carbon monoxide, and nitrogen oxide in the gas are removed by oxidation and reduction reaction, the outlet D leads to the collecting chamber 65 (second expansion chamber N), and the exhaust pipe 57 passes through the third expansion chamber O. And is discharged to the outside through the exhaust pipe 371.

In this configuration, in the multi-chamber type muffler, the catalyst body 353 passes through the first partition wall 325a and forms three passes.
That is, since the first and second catalyst chambers 353a and 353b also serve as two conventional communication pipes, the number of parts is reduced compared to the conventional one. Further, since the exhaust gas reciprocates in the passage of the single catalyst body 353, the catalyst is easily activated and the purification efficiency is improved. In addition, since the communication pipe that has been conventionally required can be omitted, even the muffler having the catalyst body 353 can prevent the muffler diameter from being enlarged.

FIG. 9 shows another embodiment.
In this embodiment, the catalytic converter 30 is disposed through the second partition wall 325b. The catalytic converter 30 has the same configuration as that of FIG. 8 and includes a cylindrical converter body 351 and a catalyst body 353 formed in the converter body 351. An exhaust gas introduction pipe 355 to the catalyst body 353 and an exhaust gas exhaust pipe 357 after passing through the catalyst body 353 are arranged together on the one end 351 a side of the cylindrical converter main body 351.
The muffler 325 is a multi-chamber type muffler, and the third, second, and first expansion chambers O and N partitioned by the first and second partition walls 325a and 325b from the introduction pipe 355 side. , M are formed in that order.

The catalyst body 353 includes a first catalyst chamber 353a communicating with the introduction pipe 355 via the communication pipe 361, and a second catalyst chamber 353b communicating with the discharge pipe 357 via the second expansion chamber N. The first and second catalyst chambers 353a and 353b may be set so that their cross-sectional areas are substantially equal, or the ratio thereof may be arbitrarily changed from the noise reduction efficiency. A first catalyst chamber 353 a is located inside the catalyst body 353, its inlet A communicates with the introduction pipe 355 via the communication pipe 361, and its outlet B is on the other end 531 b side of the converter body 351. The reversing chamber 363 (first expansion chamber M) communicates with the reversing chamber 363.
The inversion chamber 363 communicates with an inlet C of a second catalyst chamber 353b disposed outside the catalyst body 353, and an outlet D thereof is a collecting chamber 365 (second expansion chamber N) on the one end 351a side of the converter body 351. A discharge pipe 357 communicates with the collecting chamber 365.
The exhaust pipe 357 communicates with the third expansion chamber O, and the third expansion chamber O communicates with the exhaust pipe 371 penetrating the first and second partition walls 325a and 325b. The pipe 371 communicates with the outside.

The catalyst body 353 is composed of a honeycomb structure coated with platinum, palladium, rhodium or the like.
This constitutes a honeycomb type three-way catalyst, and the exhaust gas which has entered the inlet A of the first catalyst chamber 353a through the introduction pipe 355 and the communication pipe 361 described above and the hydrocarbons in the exhaust gas are oxidized. After carbon and nitrogen oxides are removed by oxidation and reduction reactions, they reach the reversal chamber 363 (first expansion chamber M) from the outlet B, enter the inlet C of the second catalyst chamber 353b from here, and exhaust again here. Hydrocarbon, carbon monoxide, and nitrogen oxide in the gas are removed by oxidation and reduction reaction, and enter the collection chamber 365 (second expansion chamber N) from the outlet D, from which the exhaust pipe 357, the third expansion It is discharged outside through the chamber O and the exhaust pipe 371.
In the above configuration, the catalytic converter 30 may be disposed so as to penetrate any partition wall 325.

FIG. 10 shows another embodiment.
In this embodiment, the catalytic converter 30 is disposed through the first partition wall 325a. The catalytic converter 30 has the same configuration as that of FIG. 8 and includes a cylindrical converter main body 351 and a catalyst body 353 formed in the main body 351. An exhaust gas introduction pipe 355 to the catalyst body 353 and an exhaust gas exhaust pipe 357 after passing through the catalyst body 353 are arranged together on the one end 351 a side of the cylindrical converter main body 351.
The muffler 325 is a multi-chamber type muffler, and the third, second, and first expansion chambers O and N partitioned by the first and second partition walls 325a and 325b from the introduction pipe 355 side. , M are formed in that order.

The catalyst body 353 includes a first catalyst chamber 353a communicating with the introduction pipe 355 via the communication pipe 361, and a second catalyst chamber 353b communicating with the discharge pipe 357 via the third expansion chamber O. The first and second catalyst chambers 353a and 353b may be set so that their cross-sectional areas are substantially equal, or the ratio thereof may be arbitrarily changed from the noise reduction efficiency.
A first catalyst chamber 353 a is located inside the catalyst body 353, its inlet A communicates with the introduction pipe 355 via the communication pipe 361, and its outlet B is on the other end 531 b side of the converter body 351. The reversing chamber 363 (first expansion chamber M) communicates with the reversing chamber 363 through a communication pipe 362 that penetrates the second partition wall 325a.
The reversing chamber 363 communicates with the second expansion chamber N via a communication pipe 364 penetrating the second partition wall 325a. The second expansion chamber N is a second catalyst disposed outside the catalyst body 353. The outlet D communicates with the inlet C of the chamber 353b, and the outlet D communicates with the collecting chamber 365 (third expansion chamber O) on the one end 351a side of the converter body 351, and the discharge pipe 357 communicates with the collecting chamber 365. . The discharge pipe 357 penetrates the first and second partition walls 325a and 325b, communicates with the exhaust pipe 371, and communicates with the outside.

In the above configuration, the sealing material 391 is interposed at the connecting portion between the catalyst body 353 and the communication pipe 361 as shown in FIGS. 11A to 11C.
The sealing material 391 has a width W2 larger than the circumscribed circle diameter W1 of the honeycomb hole of the catalyst body 353, as shown in FIG. 11C. This sealing material 391 may be similarly disposed in the connecting portion between the catalyst body 353 and the communication pipe 362. When the catalyst body 353 also serves as a muffler communication pipe, by providing the sealing material 391, the exhaust gas can be reliably fed into the expansion chamber, and the function as the communication pipe is sufficiently fulfilled.
Further, in the above configuration, the connecting portion between the catalyst body 353 and the communication pipe 361 is sealed with the sealing material 391, so that the exhaust leak from the communication pipe 361 does not directly escape to the third expansion chamber O, and the exhaust gas is exhausted. The increase in sound is prevented.
In addition, it is not limited to the sealing material 391, You may join the connection part of the catalyst body 353 and the communicating pipe 361 by welding.

FIG. 12 shows another embodiment.
In this embodiment, the catalytic converter 30 is disposed through the first partition wall 325a. The catalytic converter 30 includes a cylindrical converter main body 351 and a catalyst body 353 formed in the main body 351. An exhaust gas introduction pipe 355 to the catalyst body 353 and an exhaust gas exhaust pipe 357 after passing through the catalyst body 353 are arranged together on the one end 351 a side of the cylindrical converter main body 351.
The muffler 325 is a multi-chamber type muffler, and is divided into first, second partition walls 325a and 325b from the introduction pipe 355 side, and second, first, and third expansion chambers N and M. , O are formed in that order.

The catalyst body 353 includes a first catalyst chamber X communicating with the introduction tube 355 via a communication tube 361, a second catalyst chamber Y communicating the first and second expansion chambers M and N, and exhaust gas exhaust. And a third catalyst chamber Z that also functions as a pipe 357. As shown in FIGS. 13A and 13B, the first catalyst chamber X and the second catalyst chamber Y each have a circular cross section, and the third catalyst chamber Z includes the first catalyst chamber X and the second catalyst chamber X. It arrange | positions so that the two catalyst chambers Y may be enclosed.
The inlet A of the first catalyst chamber X communicates with the introduction pipe 355 via the communication pipe 361, and the outlet B communicates with the reversing chamber 363 (first expansion chamber M) on the other end 531 b side of the converter body 351. ing. The reversing chamber 363 communicates with the inlet C of the second catalyst chamber Y, and the outlet D communicates with the collecting chamber 365 (second expansion chamber N) on the one end 351a side of the converter body 351. Is connected to the inlet E of the third catalyst chamber Z. The outlet F communicates with a communication pipe 368 penetrating the second partition wall 325b, and the communication pipe 368 communicates with the exhaust pipe 371 through the third expansion chamber O.

In the catalyst body 353, as shown in FIG. 12, the exhaust gas first flows through the first catalyst chamber X as indicated by the arrow 1 and is reversed in the reversing chamber 363. After flowing in the collecting chamber 365, the third catalyst chamber Z flows as shown by the arrow 3, flows into the third expansion chamber O through the communication pipe 368, and is discharged from the exhaust pipe 371. .
In this configuration, three paths of the muffler 325 are configured by the single catalyst body 353, and the first catalyst chamber X to the third catalyst chamber Z also serve as three conventional communication pipes. Is reduced. Further, since the exhaust gas reciprocates once and half in the passage of the single catalyst body 353, the catalyst is more easily activated, and the purification efficiency is further improved. In addition, since the communication pipe that has been necessary in the past can be almost omitted, even the muffler having the catalyst body 353 can prevent the muffler diameter from being enlarged.

14 and 15 show another embodiment.
In this embodiment, the same catalytic converter 30 as in FIG. 4 is covered with a full cover 401 as a protector. When the catalyst body 53 of the catalytic converter 30 is flooded and a rapid thermal change occurs, distortion may occur between the converter body 51 and the one end 51a. In this configuration, since the catalytic converter 30 is covered with the full cover 401, the catalyst body 53 is waterproofed, the heat from the catalyst body 53 is shielded, and further the catalyst body from stone jumping or the like. 53 is protected.
Note that the catalytic converter 30 inside the full cover 401 is not limited to the form shown in FIG. 4 and may be any converter.

Figures 16a and 16b show another embodiment.
The catalytic converter 30 includes a converter main body (outer cylinder) 551, and an inner cylinder 559 for partitioning is concentrically provided in the outer cylinder 551. In the inner cylinder 559, the first catalyst body 561 is disposed with an appropriate gap δ1, and this portion constitutes the first catalyst chamber 553a. In addition, in the annular space surrounded by the outer cylinder 551 and the inner cylinder 559, the second catalyst body 562 is disposed on the outer peripheral side and the inner peripheral side with appropriate gaps δ2, δ3, respectively. The site | part comprises the 2nd catalyst chamber 553b. As shown in FIG. 17, the first catalyst body 561 and the second catalyst body 562 are both stacked with a flat plate 563 and a corrugated plate 564 and wound in a roll shape from one end to the other end. As will be described later, the flat plate 563 and the corrugated plate 564 are brazed.

  In this configuration, the exhaust gas that has entered the first catalyst chamber 553a (first catalyst body 561) via the introduction pipe 555 oxidizes and reduces hydrocarbons, carbon monoxide, and nitrogen oxide in the exhaust gas. After being purified by the reaction, the reversal space 563 is reached, from which it enters the second catalyst chamber 553b (second catalyst body 562), where the hydrocarbons, carbon monoxide, and nitrogen oxide in the exhaust gas are again oxidized. Then, it is purified by the reduction reaction and discharged to the muffler 25 through the discharge pipe 557.

The first catalyst body 561 has its inlet side 561a exposed to a relatively high temperature compared to the outlet side 561b, and the second catalyst body 562 has its inlet side 562a exposed to a relatively high temperature compared to the outlet side 562b. Generally, when a high temperature part is brazed, the thermal stress generated in the brazed part is increased, and the durability is lowered. Therefore, in the present configuration, between the flat plate 563 and the corrugated plate 564 of each catalyst body 561, 562, a joining region P (hatching) located on the exhaust gas discharge direction exit side 561b, 562b in the axial direction of each catalyst body 561, 562. Only the area indicated by.) Is brazed.
Further, in this configuration, between the outer periphery of the first catalyst body 561 and the inner periphery of the inner cylinder 559 (part of the gap δ1), between the inner periphery of the annular second catalyst body 562 and the outer periphery of the inner cylinder 559 (part of the gap δ3). ), And the outer periphery of the annular second catalyst body 562 and the inner periphery of the outer cylinder 551 (the portion of the gap δ2) are joined by brazing. Also in this case, for the same reason as described above, only the joining region Q (the region indicated by the thick line) located on the exhaust gas discharge direction exit side 561b, 562b in the axial direction of each catalyst body 561, 562 is brazed. Has been.
Thus, after brazing the first catalyst body 561 inside the inner cylinder 559 and brazing the second catalyst body 562 in the annular space between the inner cylinder 559 and the outer cylinder 551, the first catalyst body 561 and The flat plate 563 and the corrugated plate 564 that constitute the second catalyst body 562 are each loaded with a catalyst such as platinum, palladium, and rhodium.

  In this configuration, the gap between the outer periphery of the inlet side 561a of the first catalyst body 561 and the inner periphery of the inner cylinder 559 is not brazed, and a gap δ1 is formed, so that the first catalyst body 561 comes into contact with the exhaust gas. Even when the inlet side 561a becomes high temperature, the heat of the inlet side 561a is not easily transmitted to the inner cylinder 559, and a decrease in the material strength due to the temperature rise is suppressed. Therefore, an inexpensive material can be used for the material. In addition, since the temperature of the outlet side 562b of the second catalyst body 562 provided on the outer periphery of the inner cylinder 559 can be increased by radiant heat or the like while suppressing an extreme heat rise, the activity of the outlet side 562b during the cold start can be increased. Can be expedited.

FIG. 18 shows another embodiment.
The catalytic converter 30 includes a converter body 651 and a porous honeycomb catalyst body 653 coated with platinum, palladium, rhodium, or the like. The catalyst body 653 is formed by winding a flat plate and a corrugated plate (see FIG. 17), and communicates with the introduction pipe 655 via the communication pipe 661. The second catalyst chamber 653b that is communicated with the discharge pipe 657 and is formed of another porous portion is configured. In the present configuration, the space between the flat plate and the corrugated plate in the partial porosity (first catalyst chamber 653a) is a joint region P1 (shown by hatching) located on the exit side in the exhaust gas discharge direction in the axial direction of the partial porosity. ) Is brazed, and the joining region P2 (hatching) located between the flat plate and the corrugated plate in the other porous portion (second catalyst chamber 653b) is located on the outlet side in the exhaust gas discharge direction in the axial direction of the other porous portion. Only the area indicated by.) Is brazed. In this configuration, the honeycomb type catalyst body 653 and the inner periphery of the converter main body 651 are joined by brazing. In this case, only the joining region Q1 (the region indicated by the thick line) located on the exhaust gas discharge direction exit side in the axial direction of the catalyst body 653 is brazed.

In this configuration, the exhaust gas that has entered the inlet A of the first catalyst chamber 653a through the introduction pipe 655 and the communication pipe 661 oxidizes hydrocarbons, carbon monoxide, and nitrogen oxide in the exhaust gas. After purification by the reduction reaction, the outlet B leads to the reversal chamber 663, from which it enters the inlet C of the second catalyst chamber 653b, where again the hydrocarbons, carbon monoxide and nitrogen oxides in the exhaust gas are oxidized. It is purified by the reduction reaction, reaches the collecting chamber 665 from the outlet D, and is discharged from the discharge pipe 657 to the muffler 25.
In the above configuration, since all the pores of the honeycomb penetrate from one end of the catalyst body 653 to the other end, when the communication pipe 661 is connected to a part (center side) of one end of the catalyst body 653, a part of The exhaust gas is allowed to flow in one direction as a porous communication pipe (first catalyst chamber 653a) as it is, and the exhaust gas reversed in the reversing chamber 663 at the other end of the catalyst body 653 is now another part of the porous pores of the honeycomb ( The second catalyst chamber 653b) flows in the reverse direction. In other words, the function of one honeycomb catalyst body 653 also serves as a two-way communication pipe.

  In this configuration, since the upstream side of the exhaust gas, which is at a high temperature, is avoided and the exhaust gas outlet side where the influence of heat is small is brazed, the material strength is reduced due to the temperature increase in each joint region P, Q. An inexpensive material can be used.

  As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this. For example, in the above-described embodiment, the catalyst layout of the motorcycle has been described. However, the present invention can also be applied to catalyst layouts of three-wheeled vehicles and four-wheeled vehicles classified as other ATVs (terrain traveling vehicles).

1 is a side view of a vehicle according to an embodiment of the present invention. It is a bottom view of the vehicle shown in FIG. It is the side view. It is a structural diagram of a catalytic converter. It is sectional drawing similarly. It is a structural diagram of a catalytic converter showing another embodiment. It is a structural diagram of a catalytic converter showing another embodiment. It is a structural diagram of a catalytic converter showing another embodiment. It is a structural diagram of a catalytic converter showing another embodiment. It is a structural diagram of a catalytic converter showing another embodiment. A is a cross-sectional view showing a joint portion between a catalyst body and a connecting pipe, B is a plan view showing a sealing material, and C is a diagram for explaining the size of the sealing material. It is a structural diagram of a catalytic converter showing another embodiment. A is a P-P cross-sectional view of FIG. 12, and B is a Q-Q cross-sectional view of FIG. It is a structural diagram of a catalytic converter showing another embodiment. It is sectional drawing similarly. A and B are a structural view and a cross-sectional view showing another embodiment. It is a figure which shows a flat plate and a corrugated sheet. It is a structural diagram which shows another embodiment.

Explanation of symbols

6 Engine 15 Leg shield 23 Exhaust pipe 25 Muffler 30 Catalytic converter 39 Under guard 43 Step 47 Exhaust pipe protector 53 Catalytic body 55 Introduction pipe 57 Exhaust pipe 401 Full cover

Claims (10)

An exhaust system for a vehicle in which a muffler is connected to an exhaust pipe extending from an engine , wherein the exhaust pipe extends in the front-rear direction of the vehicle at a position below the engine and deviated to one side of the engine in the left-right direction of the vehicle. A catalytic converter extending in the vehicle lateral direction from the exhaust pipe so as to intersect the extending direction of the exhaust pipe, and the catalytic converter includes an exhaust gas introduction pipe and a discharge pipe for the catalyst chamber. Are arranged together on one end side of the catalyst chamber, and the catalyst chamber includes a first catalyst chamber communicating with the introduction pipe and a second catalyst chamber communicating with the discharge pipe. The catalyst chamber communicates with the other end side of the catalyst chamber, and the exhaust gas that has passed through the introduction pipe passes through the first catalyst chamber, then reverses at the other end side, and then passes through the second catalyst chamber. The catalyst converter to reach the discharge pipe There is formed, the catalytic converter, an exhaust device for a vehicle characterized in that it is arranged inside in the vehicle width direction directly below and the engine of the engine. The catalytic converter includes an outer cylinder and an inner cylinder,
The first catalyst chamber is surrounded by an inner cylinder and includes a first catalyst body, and the second catalyst chamber is surrounded by an inner cylinder and an outer cylinder and includes a second catalyst body. Is formed by overlapping and winding a flat plate and a corrugated plate, and between the flat plate and the corrugated plate of each catalyst body, between the catalyst body and the inner cylinder, and between the catalyst body and the outer cylinder, the exhaust gas in the axial direction of each catalyst body. bonding region located in the discharge direction out side, an exhaust device for a vehicle according to claim 1, characterized in that it is brazed. 2. The exhaust system for a vehicle according to claim 1, wherein the first catalytic chamber of the catalytic converter is disposed in front of the second catalytic chamber in the longitudinal direction of the vehicle. The catalytic converter includes a honeycomb-type catalyst body, and exhaust gas to the catalyst body that has passed through the introduction pipe passes through the first catalyst chamber formed by a part of the honeycomb-type pores, and then the honeycomb-type catalyst body. The exhaust system for a vehicle according to claim 1, further comprising a configuration that passes through the second catalyst chamber formed by a porous portion of the other portion and reaches a discharge pipe. 5. The exhaust of a vehicle according to claim 4, wherein the catalytic converter includes a partition partitioning a space between an inlet side to the catalyst body and an outlet side from the catalyst body on one end side of the catalyst chamber. apparatus. The honeycomb-type catalyst body is formed by winding a flat plate and a corrugated plate, and between the flat plate and the corrugated plate in a part of the pores is located on the exhaust gas discharge direction exit side in the axial direction of the part of the pores. Only the joining area is brazed, and between the flat plate and the corrugated sheet in the other part of the porosity, the joining area located on the outlet side in the exhaust gas discharge direction in the axial direction of the other part of the porous part is brazed. The exhaust system for a vehicle according to claim 4, wherein The porosity of a part or other part of the honeycomb type is a porosity of a central part of the honeycomb type, and the other part or part of the porosity of the honeycomb type is a porosity of an outer peripheral part of the honeycomb type. The exhaust device for a vehicle according to claim 4 or 6 . The exhaust system for a vehicle according to any one of claims 1 to 7 , wherein the catalytic converter is disposed in front of a driver's step. The exhaust system for a vehicle according to any one of claims 1 to 8 , wherein the catalytic converter is disposed inside the leg shield in the vehicle width direction. Exhaust device for a vehicle of any one of claims 1 to 9, characterized in that the exhaust pipe protector is disposed between the exit exhaust and introduction pipe connected catalytic converter in the exhaust pipe line.

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