JP2014001713A - Exhaust emission purifying system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission purifying system of an internal combustion engine in which at least a part of a catalytic converter is accommodated in an exhaust muffler and which is capable of activating a catalyst faster.SOLUTION: At a downstream end of a downstream side exhaust pipe 30A in an exhaust muffler 29A, an exhaust gas lead-out opening 44A is provided so as to open in a direction toward a part of an upstream side exhaust pipe 28 accommodated within an exhaust muffler 29.

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine in which at least a part of a catalytic converter is accommodated in an exhaust muffler.

  A catalytic converter for detoxifying harmful substances such as carbon monoxide (CO) and hydrocarbons (HC) is interposed between the downstream end of the upstream exhaust pipe and the upstream end of the downstream exhaust pipe, Patent Document 1 discloses that a part of the downstream side of the upstream side exhaust pipe and the catalytic converter and all of the downstream side exhaust pipe are accommodated in an exhaust muffler.

Japanese Patent No. 4383303

  Incidentally, in order to increase the purification rate by the catalyst, it is necessary to raise the temperature of the catalyst to a predetermined temperature. In the one disclosed in Patent Document 1, the exhaust pipe accommodated in the exhaust muffler is as upstream as possible. The catalytic converter is accommodated in the exhaust muffler so as to be interposed in the exhaust muffler, and heat generated in the catalytic converter can be kept in the exhaust muffler so that the catalyst can be activated early. Regulations tend to be stricter and it is desirable to activate the catalyst earlier.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an exhaust gas purifying device for an internal combustion engine that can activate a catalyst earlier.

  To achieve the above object, the present invention provides a downstream end of an upstream exhaust pipe having an upstream end connected to a cylinder head of an engine body and a part of the downstream side accommodated in an exhaust muffler, and the exhaust muffler. In an exhaust gas purifying apparatus for an internal combustion engine in which a catalytic converter accommodated in the exhaust muffler is interposed between an upstream end of a downstream exhaust pipe accommodated in the exhaust muffler, the downstream exhaust in the exhaust muffler A first feature is that a portion of the upstream exhaust pipe accommodated in the exhaust muffler or an exhaust gas outlet opening toward the catalytic converter is provided at a downstream end of the pipe.

  The present invention also provides a downstream end of an upstream exhaust pipe having an upstream end connected to the cylinder head of the engine body and a downstream end disposed outside the exhaust muffler, and a downstream exhaust pipe accommodated in the exhaust muffler. In an exhaust gas purification apparatus for an internal combustion engine in which a catalytic converter in which at least a part is accommodated in the exhaust muffler is interposed between the upstream end and the downstream end of the downstream exhaust pipe in the exhaust muffler, A second feature is that an exhaust gas outlet opening that opens toward the catalytic converter is provided.

  According to the present invention, in addition to the configuration of the first or second feature, a plurality of expansion chambers partitioned so as to sequentially distribute the exhaust gas led out from the exhaust gas outlet through the exhaust muffler. A third feature is that at least a part of the catalytic converter is formed in the expansion chamber located upstream of the expansion chambers.

  According to a fourth aspect of the present invention, in addition to any of the configurations of the first to third features, a stay that supports a downstream end portion of the downstream side exhaust pipe is provided in the exhaust muffler.

  According to the present invention, in addition to any of the first to fourth features, the exhaust muffler is disposed below a seat for riding in a saddle-ride type vehicle and outside the rear wheel, and the exhaust gas outlet port However, it is 5th characteristic to be arrange | positioned inside a vehicle width direction rather than the said catalytic converter.

  According to the present invention, in addition to the configuration of the fifth feature, a support stay for supporting the exhaust muffler on the vehicle body side on the outer surface inside the vehicle width direction of the exhaust muffler is at least of the catalytic converter in a side view. It is a sixth feature that it is attached so as to partially overlap the exhaust gas outlet.

  In the present invention, in addition to the configuration of the first feature, the exhaust gas outlet port is disposed in front of and above the catalytic converter housed in the lower half of the exhaust muffler when mounted on a vehicle, A casing includes a lower wall that is close to the catalytic converter from below and a front wall that continues to the front end of the lower wall, and extends rearwardly downward from a portion corresponding to the exhaust gas outlet and continues to the front end of the lower wall. A seventh feature is that an inclined wall portion is formed at a lower portion of the front wall.

  In addition to the seventh feature, the present invention provides the catalytic converter by forming, in the exhaust muffler, an expansion chamber in which the exhaust gas outlet and the catalytic converter are disposed together with the front wall. An eighth feature is that a separator is provided at the rear of the vehicle in the front-rear direction.

  According to the first aspect of the present invention, the exhaust heat of the exhaust gas having a relatively high temperature after passing through the catalytic converter is positively transmitted to a portion of the upstream exhaust pipe accommodated in the exhaust muffler or the catalytic converter. Thus, the exhaust heat can accelerate the temperature of the upstream side of the catalytic converter or the catalytic converter so that the catalyst can be activated early. In addition to the heat generated by the catalyst or the heat generated by the catalyst, the heat generated from the portion of the upstream exhaust pipe accommodated in the exhaust muffler can be further accelerated by a synergistic effect with the exhaust muffler. The temperature of the catalyst can be increased.

  Further, according to the second feature of the present invention, the exhaust heat of the exhaust gas having a relatively high temperature after passing through the catalytic converter is actively guided to the catalytic converter, and the temperature of the catalytic converter is accelerated by this exhaust heat. Thus, early activation of the catalyst can be achieved. In addition, the temperature of the catalyst can be raised more rapidly by a synergistic effect with keeping the heat generated by the catalyst in the exhaust muffler.

  According to the third aspect of the present invention, the expansion that is the highest among the plurality of expansion chambers due to the heat generated by the catalytic converter and the heat that the exhaust gas derived from the exhaust gas outlet of the downstream side exhaust pipe has. By arranging at least a part of the catalytic converter in the chamber, the temperature rise of the catalyst can be promoted.

  According to the fourth feature of the present invention, since the downstream end of the downstream exhaust pipe is supported by a stay provided in the exhaust muffler, the downstream end of the downstream exhaust pipe is changed depending on the direction of the exhaust gas outlet. Even if it must be bent, it is possible to stably support the downstream end of the downstream exhaust pipe, and to firmly support the downstream end of the downstream exhaust pipe against vibrations of the engine body, etc. it can.

  According to the fifth feature of the present invention, the exhaust gas outlet is disposed on the inner side in the vehicle width direction than the catalytic converter in the exhaust muffler disposed below the riding seat and outside the rear wheel. The exhaust gas led out from the exhaust gas outlet is led to the portion of the upstream exhaust pipe that is housed in the exhaust muffler or the inside in the vehicle width direction of the catalytic converter, and the outer surface of the exhaust muffler outside in the vehicle width direction is It is possible to prevent the exhaust gas derived from the exhaust gas outlet from being heated more than necessary, and to improve the comfortability of the passenger sitting on the passenger seat.

  According to the sixth aspect of the present invention, the vehicle width of the exhaust muffler is such that a support stay for supporting the exhaust muffler on the vehicle body side overlaps at least a part of the catalytic converter and the exhaust gas outlet in a side view. Since it is attached to the outer surface on the inner side in the direction, it is possible to reduce heat damage to the rear wheel and the parts arranged on the inner side in the vehicle width direction of the exhaust muffler.

  According to the seventh aspect of the present invention, the exhaust gas outlet is disposed in front of the catalytic converter in the exhaust muffler, and the lower wall of the exhaust muffler is adjacent to the catalytic converter from below and is connected to the front end of the lower wall. An inclined wall portion extending downward from the portion corresponding to the downstream end opening and continuing to the front end of the lower wall is formed at the lower portion of the wall, so that the exhaust gas led out from the exhaust gas outlet port is inclined to the front wall. It is possible to guide the catalyst around the catalytic converter by the section and the lower wall, and to raise the temperature of the catalyst even more efficiently. Moreover, since the catalytic converter is housed in the lower half of the exhaust muffler, it is possible to lower the center of gravity of the exhaust muffler and thus lower the center of gravity of the vehicle.

  Furthermore, according to the eighth feature of the present invention, the exhaust gas led out from the exhaust gas outlet can be made to stay against the separator behind the catalytic converter, and the catalytic converter can be placed between the exhaust gas outlet and the separator. Thus, the temperature can be raised even more efficiently.

1 is a right side view of a motorcycle according to a first embodiment. It is a vertical side view of an exhaust muffler. It is sectional drawing which follows the 3-3 line of FIG. FIG. 3 is a diagram showing a catalytic converter and a downstream exhaust pipe in an exhaust muffler as seen from the direction of arrow 4 in FIG. 2. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. It is a vertical side view of the exhaust muffler corresponding to FIG. 2 of 2nd Embodiment. It is a principal part right view of the motorcycle of 3rd Embodiment. It is a vertical side view of the exhaust muffler corresponding to FIG. It is a vertical side view of the exhaust muffler corresponding to FIG. 2 of 4th Embodiment.

  Embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, front and rear, left and right, and top and bottom refer to directions viewed from a passenger who rides a motorcycle.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, in FIG. 1, a vehicle body frame F of a scooter type motorcycle that is a saddle-ride type vehicle is a front that pivotally supports a front wheel WF. A head pipe 13 that supports the fork 11 and the steering handle 12 connected to the front fork 11 so as to be steerable, a down tube 14 that extends rearwardly downward from the head pipe 13, and a down tube 14 that extends in the vehicle width direction. The cross member 15 is fixed to the rear end of the rear member, and a pair of left and right rear frame pipes 16 are attached to the left and right sides of the cross member 15 to extend rearward.

  A bracket 17 is provided at the front end of the rear frame pipes 16 in the body frame F. A front portion of the power unit P is supported on the bracket 17 via a link mechanism 18 so as to be swingable up and down, and a rear wheel WR disposed on the right side of the rear portion of the power unit P is pivotally supported on the rear portion of the power unit P. The

  The vehicle body frame F is covered with a synthetic resin vehicle body cover 19 that forms the vehicle body B in cooperation with the vehicle body frame F, and the vehicle body cover 19 covers the head pipe 13 from the front. A leg shield 21 connected to the front cover 20 so as to cover the front of the driver's feet, a step floor 22 connected to the lower portion of the leg shield 21 for placing a passenger's feet, and a rear part of the vehicle body connected to the step floor 22 And a pair of left and right pillion steps for a passenger on the rear portion of the riding seat 24 to place his / her feet on the side cover 23. 27 are disposed on the left and right sides of the rear portion of the step floor 22 and are supported by the rear frame pipes 16. .

  The power unit P includes an internal combustion engine E and a transmission device (not shown) provided between the internal combustion engine E and the rear wheel WR, and the cylinder head 26 of the engine body 25 in the internal combustion engine E. Is connected to the upstream end of the upstream exhaust pipe 28.

  Referring also to FIG. 2, a part of the downstream side of the upstream side exhaust pipe 28 is accommodated in an exhaust muffler 29 </ b> A disposed below the riding seat 24 and outside the rear wheel WR, A catalytic converter 31 accommodated in the exhaust muffler 29A is interposed between the downstream end of the upstream exhaust pipe 28 and the upstream end of the downstream exhaust pipe 30A accommodated in the exhaust muffler 29A.

  Referring also to FIG. 3, a casing 32A of the exhaust muffler 29A is formed of an outer case 33 and a punching metal having a large number of pores 36, 36, and is disposed inside the outer case 33. The inner case 34 is welded to each other at a plurality of locations, and glass wool 35 is filled between the outer case 33 and the inner case 34.

  The catalytic converter 31 is configured such that a catalyst carrier 37 carrying a catalyst is accommodated in a cylindrical tube 38 so as to allow the exhaust gas to flow. The upstream side exhaust pipe 28 has an upstream end connected to the cylinder head 26 and extending to the right side of the rear wheel WR, one end of the cylindrical body 38 in the catalytic converter 31 and the first exhaust pipe 39. An upstream connecting pipe 40 that connects the downstream ends of the exhaust pipe 39 is connected, and a part of the upstream connecting pipe 40 (the downstream half in this embodiment) is inside the casing 32A of the exhaust muffler 29A. Is housed in.

  Referring also to FIG. 4, the downstream side exhaust pipe 30 </ b> A includes a downstream side connection pipe 41 whose upstream end is connected to one end portion of the cylindrical body 38 in the catalytic converter 31, and a downstream side of the downstream side connection pipe 41. The second exhaust pipe 42A has an upstream end connected to the end, and a third exhaust pipe 43A has an upstream end connected to the downstream end of the second exhaust pipe 42A. An exhaust gas outlet 44A is provided at the downstream end of the three exhaust pipe 43A.

  Inside the exhaust muffler 29A, a plurality of expansion chambers partitioned so as to sequentially distribute the exhaust gas derived from the exhaust gas outlet port 44, in this embodiment, the first and second expansion chambers 45A. , 46 are formed, and the exhaust gas outlet 44A is arranged in the first expansion chamber 45A.

  At least a part of the catalytic converter 31 (all in the first embodiment) is disposed in the first expansion chamber 45A which is the most upstream of the first and second expansion chambers 45A and 46. The exhaust gas exhaust port 44A is disposed in front of and above the catalytic converter 31. The exhaust gas outlet 44A is accommodated in the lower half of the exhaust muffler 29 so as to be close to the lower wall 50 of the casing 32A. Thus, the separator 47 disposed behind the catalytic converter 31 is fixed to the inner surface of the casing 32A, and the first expansion is made in the casing 32A between the separator 47 and the front wall 48 of the casing 32A. A chamber 45A is formed, and the second expansion chamber 46 is formed in the casing 32A between the rear wall 49 of the casing 32A and the separator 47.

  In addition, an inclined wall portion 48 a extending rearwardly downward from a portion corresponding to the exhaust gas outlet 44 A and continuing to the front end of the lower wall 50 is formed at the lower portion of the front wall 48.

  By the way, the exhaust gas led out from the exhaust gas outlet 44A flows from the first expansion chamber 45A to the second expansion chamber 46, and communicates between the first and second expansion chambers 45A, 46. The communication pipe 51 is disposed so as to penetrate the upper part of the separator 47.

  The inclined wall 48a of the front wall 48 of the casing 32A is provided with a cylindrical portion 52 that continues to the outer case 33 and protrudes forward, and the upstream connecting pipe 40 of the upstream exhaust pipe 28 is connected to the cylindrical portion. It welds to this cylinder part 52 so that 52 may be airtightly penetrated. In addition, a discharge pipe 53 that allows the inner end to pass through the second expansion chamber 46 passes through the rear wall 49 of the casing 32 </ b> A in an airtight manner and is welded to the rear wall 49.

  The downstream connection pipe 41 of the downstream exhaust pipe 30 </ b> A penetrates the lower part of the separator 47 in an airtight manner. In addition, the second exhaust pipe 42A, whose upstream end is connected to the downstream end of the downstream connection pipe 41 in the second expansion chamber 46, has its downstream end located above the separator 47 in the second expansion chamber 46. It is formed to be curved in a substantially U shape so as to face each other. Further, the third exhaust pipe 43A penetrates the upper part of the separator 47 in an airtight manner above the communication pipe 51 so that its upstream end is connected to the downstream end of the second exhaust pipe 42A in the second expansion chamber 46. To do.

  A bracket 54 is fixed to the inner surface of the casing 32A and is disposed in front of the separator 47 and extends up and down in the upper portion of the first expansion chamber 45A. The middle portion of the third exhaust pipe 43A is the bracket. 54 is supported by the bracket 54. Further, one end of the communication pipe 51 passes through the intermediate portion in the vertical direction of the bracket 54 and is supported by the bracket 54, and the other end of the communication pipe 51 passes through the separator 47 and passes through the separator 47. Supported.

  By the way, in the first expansion chamber 45A of the exhaust muffler 29A, an exhaust gas outlet 44A provided at the downstream end of the downstream exhaust pipe 30A, that is, the downstream end of the third exhaust pipe 43A is an exhaust gas in the upstream exhaust pipe 28. It opens toward the portion accommodated in the muffler 29, that is, the downstream end of the upstream connecting pipe 40, and opens in the pointing direction indicated by the arrow 55. For this reason, the third exhaust pipe 43A is curved in a substantially J shape. Formed.

  A stay 56 for supporting the downstream end of the downstream exhaust pipe 30A, that is, the downstream end of the third exhaust pipe 43A is provided on the inner surface of the casing 32A of the exhaust muffler 29A, that is, the inner surface of the inner case 34.

  Incidentally, as shown in FIG. 4, the third exhaust pipe 43A in the downstream exhaust pipe 30A is disposed on the rear wheel WR side, that is, on the inner side in the vehicle width direction with respect to the catalytic converter 31, and is directed to the exhaust gas outlet 44A. The direction 55 is a direction in which the exhaust gas led out from the exhaust gas lead-out port 44A is led from the inner side in the vehicle width direction to the downstream end portion of the upstream connection pipe 40.

  Referring also to FIG. 5, the exhaust muffler 29A is supported on the vehicle body B side on the outer surface inside the vehicle width direction of the exhaust muffler 29A, that is, the outer surface inside the vehicle width direction of the outer case 33 in the casing 32A. A first support stay 57 is attached. As clearly shown in FIG. 2, the first support stay 57 includes at least a part of the catalytic converter 31 (substantially the front half in this embodiment) and the above-mentioned in a side view. It is formed so as to overlap the exhaust gas outlet 44A.

  The first support stay 57 is integrally formed with a first arm portion 57a and a second arm portion 57b disposed below the first arm portion 57a so as to protrude forward from the exhaust muffler 29A. Is done. Further, a second support stay 58 having an arm portion 58a protruding forward from the exhaust muffler 29A at a position corresponding to the first arm portion 57a of the first support stay 57 at the upper portion of the front wall 48 of the casing 32A. Is attached to the lower portion of the front wall 48 of the casing 32A, that is, the inclined wall portion 48a, at the position corresponding to the second arm portion 57b of the first support stay 57, and to protrude forward from the exhaust muffler 29A. A third support stay 59 is attached.

  The first arm portion 57a of the first support stay 57 and the arm portion 58a of the second support stay 58 cooperate to constitute a first support arm 60, and the second arm portion 57b of the first support stay 57 and The arm portion 59a of the third support stay 59 forms a second support arm 61 in cooperation. The distal ends of the first and second support arms 60 and 61 are fastened to the engine body 25 supported by the vehicle body B with bolts 62 and 63, and the exhaust muffler 29A is connected to the vehicle body via the engine body 25. It will be supported on the B side.

  Protector support stays 64 and 65 are attached to the lower outer surface of the exhaust muffler 29A in the vehicle width direction, that is, the outer surface of the outer lower portion of the casing 32A in the vehicle width direction with a space in the front-rear direction. The protector support stays 64 and 65 are provided with weld nuts 66 and 67, respectively.

  The lower part of the outer surface of the exhaust muffler 29A on the outer side in the vehicle width direction is covered with a protector 68. The protector 68 is attached to the protector support stays 64, 65 by bolts 69, 70 screwed into the weld nuts 66, 67. Fixed.

  Next, the operation of the first embodiment will be described. The downstream end of the upstream side exhaust pipe 28 whose upstream end is connected to the cylinder head 26 and part of the downstream side is accommodated in the exhaust muffler 29A; The catalytic converter 31 accommodated in the exhaust muffler 29A is interposed between the upstream end of the downstream exhaust pipe 30A accommodated in the exhaust muffler 29A. The downstream exhaust pipe is disposed in the exhaust muffler 29A. Since the exhaust gas outlet 44A that opens toward the portion of the upstream exhaust pipe 28 that is accommodated in the exhaust muffler 29 is provided at the downstream end of 30A, the exhaust gas outlet 44A is opened at a relatively high temperature after passing through the catalytic converter 31. The exhaust heat of a certain exhaust gas is positively guided to a portion of the upstream side exhaust pipe 28 that is accommodated in the exhaust muffler 29A, and the exhaust heat causes the upstream of the catalytic converter 31 to be upstream. The Atsushi Nobori soon, it is possible to achieve early activation of the catalyst. Moreover, in addition to the heat generated by the catalyst, the temperature of the catalyst can be increased more rapidly by the synergistic effect of keeping the heat generated from the portion of the upstream exhaust pipe 28 accommodated in the exhaust muffler 29A in the exhaust muffler 29A. Can be achieved.

  Further, first and second expansion chambers 45A and 46 are formed inside the exhaust muffler 29A so as to sequentially distribute the exhaust gas derived from the exhaust gas outlet 44A. 46, since at least a part of the catalytic converter 31 (all in the first decimal form) is disposed in the first expansion chamber 45A, which is the most upstream expansion chamber, the catalytic converter 31 is generated. The first expansion chamber 45A, which has the highest temperature among the first and second expansion chambers 45A and 46, is formed by the heat and the heat of the exhaust gas derived from the exhaust gas outlet 44A of the downstream side exhaust pipe 30A. The catalytic converter 31 is disposed, and the temperature rise of the catalyst can be promoted.

  Further, since the exhaust muffler 29A is provided with a stay 56 that supports the downstream end of the downstream exhaust pipe 30A, that is, the downstream end of the third exhaust pipe 43A, the downstream exhaust pipe 30A depends on the direction of the exhaust gas outlet 44A. Even when the downstream end of the third exhaust pipe 43A has to be bent, it is possible to stably support the downstream end of the third exhaust pipe 43A, and the downstream end of the third exhaust pipe 43A. The end portion can be firmly supported against vibration of the engine body 25 and the like.

  Further, since the exhaust muffler 29A is disposed below the riding seat 24 and outside the rear wheel WR, and the exhaust gas outlet 44A is disposed on the inner side in the vehicle width direction than the catalytic converter 31, the exhaust gas outlet 44A. The exhaust gas led out from the exhaust pipe 28 is led to the inside in the vehicle width direction of the portion of the upstream side exhaust pipe 28 accommodated in the exhaust muffler 29A, and the outer surface of the exhaust muffler 29A outside in the vehicle width direction is the exhaust gas outlet. It is possible to prevent the exhaust gas derived from 44 from being heated more than necessary, and to improve the comfortability of the occupant sitting on the riding seat 24.

  A support stay 57 for supporting the exhaust muffler 29A on the vehicle body B side overlaps at least a part of the catalytic converter 31 and the exhaust gas outlet 44A in a side view on the outer surface of the exhaust muffler 29A in the vehicle width direction. Since it is attached in this way, it is possible to reduce heat damage to the parts arranged on the inner side in the vehicle width direction of the rear wheel WR and the exhaust muffler 29A.

  Also, an exhaust gas outlet 44A is disposed in front of and above the catalytic converter 31 housed in the lower half of the exhaust muffler 29A, and the casing 32A of the exhaust muffler 29A is connected to the lower wall 50 adjacent to the catalytic converter 31 from below. And a front wall 48 connected to the front end of the lower wall 50, and an inclined wall portion 48a extending downward from a portion corresponding to the exhaust gas outlet 44A and continuing to the front end of the lower wall 50 is formed in the lower part of the front wall 48. Therefore, the exhaust gas led out from the exhaust gas lead-out port 44A can be guided around the inclined wall portion 48a and the lower wall 50 of the front wall 48 and guided to the periphery of the catalytic converter 31, and the catalyst can be more efficiently produced. The temperature can be raised. In addition, since the catalytic converter 31 is housed in the lower half of the exhaust muffler 29A, it is possible to lower the center of gravity of the exhaust muffler 29A and thereby lower the center of gravity of the vehicle.

  Further, the exhaust muffler 29A is formed with a first expansion chamber 45A in which the exhaust gas outlet 44A and the catalytic converter 31 are disposed together with the front wall 48, and is disposed behind the catalytic converter 31 in the longitudinal direction of the vehicle. Since the separator 47 is provided, the exhaust gas led out from the exhaust gas outlet 44A can be made to stay against the separator 47 behind the catalytic converter 31, and the catalytic converter 31 can be retained in the exhaust gas outlet 44A and the separator. The temperature can be increased more efficiently between 47.

  FIG. 6 shows a second embodiment of the present invention. The parts corresponding to those of the first embodiment are indicated by the same reference numerals and are not described in detail. .

  The downstream half of the upstream connecting pipe 40, which is a part of the downstream side of the upstream exhaust pipe 28, is accommodated in the exhaust muffler 29A. The downstream end of the upstream exhaust pipe 28 and the exhaust muffler 29A A catalytic converter 31 accommodated in the exhaust muffler 29A is interposed between the upstream end of the accommodated downstream exhaust pipe 30B.

  The downstream exhaust pipe 30 </ b> B includes a downstream connection pipe 41 whose upstream end is connected to one end of the cylindrical body 38 in the catalytic converter 31, and a second exhaust whose upstream end is connected to the downstream end of the downstream connection pipe 41. A pipe 42A and a third exhaust pipe 43B having an upstream end connected to the downstream end of the second exhaust pipe 42A. An exhaust gas is connected to the downstream end of the downstream exhaust pipe 30B, that is, the downstream end of the third exhaust pipe 43B. A lead-out port 44B is provided, and in the first expansion chamber 45A, the catalytic converter 31 and the exhaust gas lead-out port 44B disposed at the front upper side of the catalytic converter 31 are disposed. The third exhaust pipe 43B is curved in a substantially J-shape so as to open toward the catalytic converter 31 in the direction indicated by the arrow 71.

  A stay 56 for supporting the downstream end of the downstream exhaust pipe 30B, that is, the downstream end of the third exhaust pipe 43B is provided on the inner surface of the casing 32A of the exhaust muffler 29A, that is, the inner surface of the inner case 34.

  According to the second embodiment, the exhaust gas outlet 44B that opens toward the catalytic converter 31 is provided at the downstream end of the downstream exhaust pipe 30B in the exhaust muffler 29A. The exhaust heat of the exhaust gas having a relatively high temperature after passing through is positively guided to the catalytic converter 31, and this exhaust heat can accelerate the temperature rise of the catalytic converter 31, thereby enabling early activation of the catalyst.

  A third embodiment of the present invention will be described with reference to FIG. 7 and FIG. 8, but the parts corresponding to the first and second embodiments described above are only given the same reference numerals. Detailed description will be omitted.

  A part of the downstream side of the upstream exhaust pipe 28 whose upstream end is connected to the cylinder head 26 of the engine main body 25 in the internal combustion engine E is an exhaust muffler disposed below the riding seat 24 and outside the rear wheel WR. The catalytic converter 31 accommodated in the exhaust muffler 29B is accommodated in the exhaust muffler 29B and between the downstream end of the upstream exhaust pipe 28 and the upstream end of the downstream exhaust pipe 30C accommodated in the exhaust muffler 29B. Is installed.

  The casing 32B of the exhaust muffler 29B is disposed inside the outer case 33 so as to be filled with the glass wool 35 between the outer case 33 and the outer case 33, and is welded to the outer case 33 at a plurality of locations. An inner case 34, a cylindrical body 72 connected to the front lower portion of the outer case 33 and protruding forward and covering the periphery of the catalytic converter 31 in close proximity, and a distal end portion of the cylindrical body 72 It is comprised with the cap 73 couple | bonded.

  A plurality of expansion chambers, in this embodiment, first and second expansion chambers 45B and 46 are formed in the exhaust muffler 29B. The first expansion chamber 45B is connected to the inner case 34 at the periphery. Formed by a separator 47 to which a portion is fixed, a front portion of the inner case 34, the cylindrical body 72, and the cap 73, and the second expansion chamber 46 includes the separator 47 and a rear portion of the inner case 34. Formed with.

  At least a part (all in this embodiment) of the catalytic converter 31 is accommodated in the first expansion chamber 45B, and the first expansion chamber is arranged so that most of the catalytic converter 31 is disposed in the cylindrical body 72. 45B.

  Of the upstream exhaust pipe 28, the upstream connection pipe 40 whose downstream end is connected to one end of the cylindrical body 38 in the catalytic converter 31 is made to enter a part of the first expansion chamber 45 </ b> B. And penetrates the cap 73 in an airtight manner.

  The downstream exhaust pipe 30C includes a downstream connection pipe 41 whose upstream end is connected to the catalytic converter 31, a second exhaust pipe 42B whose upstream end is connected to the downstream end of the downstream connection pipe 41, and a second The third exhaust pipe 43C has an upstream end connected to the downstream end of the exhaust pipe 42B. The downstream end of the downstream exhaust pipe 30C, that is, the downstream end of the third exhaust pipe 43C, is in the first expansion chamber 45B. An exhaust gas outlet 44C is provided so as to be disposed.

  The downstream connection pipe 41 of the downstream exhaust pipe 30C is disposed in the first expansion chamber 45B, and the upstream end is connected to the downstream end of the downstream connection pipe 41 in the first expansion chamber 45B. The second exhaust pipe 42 </ b> B penetrates the separator 47 and is formed in a substantially J shape so that its downstream end faces the upper part of the separator 47 in the second expansion chamber 46. Further, the third exhaust pipe 43C penetrates the upper part of the separator 47 in an airtight manner so that its upstream end is connected to the downstream end of the second exhaust pipe 42A in the second expansion chamber 46.

  A bracket 54 is fixed to the inner surface of the inner case 34 and is disposed in front of the separator 47 and extends up and down in the upper part of the first expansion chamber 45B. The bracket 54 passes through and is supported by the bracket 54. One end of the communication pipe 51 communicating between the first and second expansion chambers 45B and 46 is supported by the bracket 54 through the intermediate portion in the vertical direction of the bracket 54. The end portion passes through the separator 47 and is supported by the separator 47.

  In the first expansion chamber 45B, an exhaust gas outlet 44C provided at the downstream end of the downstream exhaust pipe 30C, that is, the downstream end of the third exhaust pipe 43C is directed to the downstream portion of the catalytic converter 31 with an arrow 75. For this purpose, the third exhaust pipe 43C is formed to be curved in a substantially J shape.

  A stay 56 for supporting the downstream end of the downstream exhaust pipe 30C, that is, the downstream end of the third exhaust pipe 43C is provided on the inner surface of the casing 32B of the exhaust muffler 29B, that is, the inner surface of the inner case 34.

  Referring to FIG. 7, the outer surface lower portion of the exhaust muffler 29B in the vehicle width direction outer side, that is, the outer surface lower portion of the outer case 33 in the vehicle width direction outer side lower portion of the casing 32B is covered with a protector 68. The cylindrical body 72 and the cap 73 constituting a part, and most of the upstream side exhaust pipe 28 are covered with a second protector 74. Moreover, the front portion of the protector 68 is formed so as to cover the rear portion of the second protector 74 from the outside.

  Also in the third embodiment, the same effect as in the second embodiment can be obtained.

  FIG. 9 shows a fourth embodiment of the present invention. The parts corresponding to those of the first to third embodiments are only given the same reference numerals and are described in detail. Is omitted.

  At least a part of the exhaust muffler 29A is accommodated between the downstream end of the upstream exhaust pipe 28 arranged outside the exhaust muffler 29A and the upstream end of the downstream exhaust pipe 30C accommodated in the exhaust muffler 29A. An exhaust gas outlet 44C that opens toward the catalytic converter 31 is provided at the downstream end of the downstream exhaust pipe 30C in the exhaust muffler 29A.

  The catalytic converter 31 is fixed to the casing 32A such that a front portion thereof protrudes forward from a front portion of the casing 32A in the exhaust muffler 29A, and a part of the downstream side of the catalytic converter 31 is an exhaust muffler 29A. Is accommodated in the first expansion chamber 45A.

  Thus, in the first expansion chamber 45B, the exhaust gas outlet 44C provided at the downstream end of the downstream exhaust pipe 30C, that is, the downstream end of the third exhaust pipe 43C is directed toward the downstream portion of the catalytic converter 31. Open in the direction indicated by the arrow 75.

  According to the fourth embodiment, the exhaust heat of the exhaust gas having a relatively high temperature after passing through the catalytic converter 31 is actively guided to the catalytic converter 31, and the temperature of the catalytic converter 31 is increased by the exhaust heat. As a result, the catalyst can be activated early. In addition, the temperature of the catalyst can be increased more rapidly by the synergistic effect of maintaining the heat generated by the catalyst in the exhaust muffler 29A.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

24 ... Riding seat 25 ... Engine body 26 ... Cylinder head 28 ... Upstream exhaust pipes 29A, 29B ... Exhaust mufflers 30A, 30B, 30C ... Downstream exhaust pipes 31 ... Catalytic converter 32A ... casings 44A, 44B, 44C ... exhaust gas outlets 45A, 45B, 46 ... expansion chamber 47 ... separator 48 ... front wall 48a ... inclined wall 50 ..Lower wall 56 ... Stay 57 ... Support stay B ... Body WR ... Rear wheel

Claims (8)

  An upstream end is connected to the cylinder head (26) of the engine body (25) and a downstream part of the engine body (25) is accommodated in the exhaust muffler (29A), and the exhaust muffler The exhaust gas of the internal combustion engine in which the catalytic converter (31) accommodated in the exhaust muffler (29A) is interposed between the upstream ends of the downstream exhaust pipes (30A, 30B) accommodated in (29A). In the purification apparatus, a portion of the upstream exhaust pipe (28) accommodated in the exhaust muffler (29) at the downstream end of the downstream exhaust pipe (30A, 30B) in the exhaust muffler (29A). Alternatively, an exhaust gas purifying apparatus for an internal combustion engine, characterized in that exhaust gas outlets (44A, 44B, 44C) opening toward the catalytic converter (31) are provided.   An upstream end is connected to the cylinder head (26) of the engine body (25) and a downstream end is disposed outside the exhaust muffler (29A), and a downstream end of the upstream exhaust pipe (28), and the exhaust muffler (29A) Exhaust gas purification of an internal combustion engine in which a catalytic converter (31) at least partially accommodated in the exhaust muffler (29A) is interposed between the upstream end of the downstream exhaust pipe (30C) accommodated in the exhaust muffler (29A) In the apparatus, an exhaust gas outlet (44C) that opens toward the catalytic converter (31) is provided at the downstream end of the downstream exhaust pipe (30C) in the exhaust muffler (29A). An exhaust gas purification device for an internal combustion engine.   Inside the exhaust muffler (29A, 29B), a plurality of expansion chambers (45A, 45B; 46) partitioned so that the exhaust gas led out from the exhaust gas outlets (44A, 44B, 44C) is circulated sequentially. ), And at least a part of the catalytic converter (31) is disposed in the expansion chamber (45A, 45B) on the most upstream side among the expansion chambers (45A, 45B; 46). The exhaust gas purification device for an internal combustion engine according to claim 1 or 2.   The exhaust muffler (29A, 29B) is provided with a stay (56) that supports the downstream end of the downstream exhaust pipe (30A-30C). An exhaust gas purification device for an internal combustion engine as described.   The exhaust muffler (29A, 29B) is disposed below the riding seat (24) of the saddle-ride type vehicle and outside the rear wheel (WR), and the exhaust gas outlets (44A to 44C) are connected to the catalyst. The exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 4, wherein the exhaust gas purification device is disposed on the inner side in the vehicle width direction than the converter (31).   A support stay (57) for supporting the exhaust muffler (29A, 29B) on the vehicle body (B) side is provided on the outer surface inside the vehicle width direction of the exhaust muffler (29A, 29B) in the side view. The exhaust gas purifying device for an internal combustion engine according to claim 5, wherein the exhaust gas purifying device is attached so as to overlap at least a part of (31) and the exhaust gas outlet (44A to 44C).   The exhaust gas outlets (44A, 44B) are arranged in front of and above the catalytic converter (31) accommodated in the lower half of the exhaust muffler (29A) in a vehicle-mounted state, and the exhaust muffler (29A) The casing (32A) includes a lower wall (50) adjacent to the catalytic converter (31) from below and a front wall (48) connected to the front end of the lower wall (50), and the exhaust gas outlet port (44A). , 44B), an inclined wall portion (48a) extending downward from the portion corresponding to the front end of the lower wall (50) is formed at a lower portion of the front wall (48). An exhaust gas purification device for an internal combustion engine as described.   In the exhaust muffler (29A), an expansion chamber (45A) in which the exhaust gas outlets (44A, 44B) and the catalytic converter (31) are disposed is formed between the front wall (48) and the exhaust muffler (29A). The exhaust gas purifying device for an internal combustion engine according to claim 7, further comprising a separator (47) disposed behind the catalytic converter (31) in the front-rear direction of the vehicle.

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