JP5396152B2 - Motorcycle - Google Patents

Description

  The present invention relates to an improvement in a motorcycle including a catalyst in an exhaust passage of an engine.

  2. Description of the Related Art A motorcycle including a catalyst that purifies exhaust gas in the middle of an engine exhaust passage is known (see, for example, Patent Document 1 (FIGS. 7 and 4)).

  In FIG. 7 of Patent Document 1, an exhaust device 25 for a motorcycle (the reference sign is the same as that of the same publication. The same applies hereinafter) includes four exhaust pipes 27a to 27d connected to the exhaust port of the engine, These four exhaust pipes 27a to 27d extend rearward, and the left two exhaust pipes 27a and 27b merge together into a left merge pipe 28a and the right two exhaust pipes 27c and 27d. A right joining pipe 28b that joins them together, a first muffler 29 connected to the downstream side of these joining pipes 28a and 28b, and a second muffler 29 connected to the first muffler 29 via a connecting pipe 30; The muffler 31 is a main component. A first catalyst for purifying exhaust gas is housed in the pair of left and right joining pipes 28a and 28b, and a second catalyst is housed in a first muffler 29 provided on the downstream side of the joining pipes 28a and 28b.

  In FIG. 4 of Patent Document 1, a merging pipe 28a is a member having a cylindrical cross section, and a first catalyst 43 is accommodated inside. The upper part of the merge pipe 28a is disposed in a recess 15c formed in the bottom of the oil pan 15b. By arranging the upper part of the merging pipe 28a in the recess 15c, the minimum ground height (HL) of the merging pipe 28a is secured.

By the way, in the technique of Patent Document 1, if the size of the first catalyst 43 is to be increased, the outer diameter of the merging pipe 28a becomes larger, and it is necessary to move the merging pipe 28a downward. If it does so, there exists a subject that minimum ground height HL of a vehicle becomes low.
Even when the size of the first catalyst 43 is increased, a technique is desired in which the height of the first catalyst can be suppressed and the minimum ground height HL of the vehicle can be easily increased.

JP2007-8442A

  The present invention relates to a motorcycle in which a first catalyst is provided in an exhaust passage and a second catalyst is provided downstream of the first catalyst, thereby enabling a minimum ground height of the vehicle to be easily increased. It is an issue to provide.

The invention according to claim 1 is a vehicle body frame, an engine attached to the vehicle body frame, an exhaust passage that extends rearward and passes through the lower part of the engine, and an exhaust passage through which the exhaust gas passes. In a motorcycle provided with a first catalyst disposed below a vehicle body frame and a second catalyst disposed adjacent to the downstream side of the first catalyst in the exhaust passage, the first catalyst and the first catalyst The two catalysts are housed in a chamber housing portion, a chamber mounting portion for mounting the chamber housing portion on the vehicle body frame side is mounted above the first catalyst, and the chamber housing portion is a first catalyst in which the first catalyst is housed. The storage portion and a second catalyst storage portion in which the second catalyst is stored, and the chamber storage portion has an enlarged diameter that expands in the downstream direction between the first catalyst storage portion and the second catalyst storage portion. Part A chamber mounting portion is mounted on top of the first catalyst storage unit, the first catalyst exhibits a cross-sectional oval shape extending long axis along the vehicle width direction, the ground of the upper surface of the first catalyst The height from the ground on the upper surface of the second catalyst is set lower than the height from the ground on the upper surface of the first catalyst storage unit. It is characterized by being set lower than the above.

  The invention according to claim 2 is characterized in that a rear exhaust passage is extended rearward from the rear portion of the chamber housing portion, and the rear exhaust passage is attached to the body frame side.

  In the invention which concerns on Claim 3, the height from the ground of the upper surface of a 1st catalyst storage part is the height from the ground of the upper surface of the exhaust passage connected immediately before the 1st catalyst storage part among exhaust passages. The first catalyst is arranged rearward of an oil pan that swells below the engine and is provided.

In the invention according to claim 4, the engine includes a plurality of cylinders, the exhaust passages are extended from the cylinders, and the plurality of exhaust passages are arranged in the vehicle width direction in front of the first catalyst storage portion of the chamber storage portion. It is characterized by being.
In the invention according to claim 5, the exhaust passage has a bypass passage through which the exhaust gas passes through the chamber housing portion separately from the path connected to the first catalyst housing portion from the front of the first catalyst housing portion. To do.
In the invention which concerns on Claim 6, the junction part of a bypass channel and a chamber accommodating part is connected between the 1st catalyst and the 2nd catalyst, It is characterized by the above-mentioned.
The invention according to claim 7 is characterized in that the axis of the first catalyst and the axis of the second catalyst are arranged in front of and behind the vehicle so as to be substantially on the same line.

  In the invention according to claim 1, the first catalyst has an oval cross section in which the major axis extends along the vehicle width direction, so that the cross sectional area of the first catalyst can be increased. If the cross-sectional area of the first catalyst is increased, a large capacity of the first catalyst is ensured and the height of the first catalyst can be suppressed.

In addition, the chamber attachment portion is attached to the upper portion of the first catalyst storage portion.
The upper surface height of the first catalyst storage unit is set to be lower than the upper surface height of the second catalyst storage unit disposed adjacent to the downstream side of the first catalyst storage unit. And the chamber attachment part is provided in the upper surface of the 1st catalyst storage part by which height is set lower than the upper surface height of the 2nd catalyst storage part. Since the chamber attachment portion is provided on the upper surface of the first catalyst accommodation portion that is lower than the upper surface height of the second catalyst accommodation portion, even when this chamber attachment portion is provided, the first catalyst accommodation portion bulges downward. It becomes difficult. If it becomes difficult for the first catalyst storage portion to bulge downward, the chamber storage portion can be supported while the ground height of the first catalyst storage portion is kept high.

  Therefore, even when the size of the first catalyst is increased, the height of the first catalyst can be suppressed, and the ground height of the first catalyst storage portion can be kept high. Can be easily increased.

  In the invention according to claim 2, the rear exhaust passage extending to the rear portion of the chamber housing portion is attached to the body frame side. The chamber storage part is supported by the upper part of the 1st catalyst storage part which comprises the front part of a chamber storage part, and the rear exhaust passage arrange | positioned at the back of a chamber storage part. That is, the chamber storage part is attached to the body frame side at the front of the chamber storage part and behind the chamber storage part. Since the chamber storage is supported in the longitudinal direction, the chamber storage can be more securely attached to the vehicle body side than when the chamber storage is attached to the vehicle body frame on the left and right sides in the width direction of the chamber storage. become.

  In the invention which concerns on Claim 3, the height from the ground of the upper surface of a 1st catalyst storage part is set high with respect to the height from the ground of the upper surface of the exhaust passage connected immediately before the 1st catalyst storage part. Therefore, the downward expansion of the first catalyst storage unit can be suppressed. In addition, since the first catalyst is disposed rearward of the oil pan that swells and is provided below the engine, the capacity of the oil pan can be sufficiently secured.

  The height of the upper surface of the first catalyst storage unit is set higher than the height of the upper surface of the exhaust passage connected immediately before the first catalyst storage unit, and the first catalyst is arranged behind the oil pan. Therefore, it is possible to secure a sufficient oil pan capacity, to secure a sufficient cross-sectional area of the catalyst, and to make the minimum ground clearance of both sufficient.

  In the invention according to claim 4, the engine includes a plurality of cylinders, the exhaust passages are extended from the cylinders, and the plurality of exhaust passages are arranged in the vehicle width direction in front of the first catalyst storage portion of the chamber storage portion. Has been. Since the exhaust passages are arranged in the vehicle width direction, the height direction dimension of the exhaust passage can be suppressed, and it is easy to ensure the minimum ground clearance.

1 is a left side view of a motorcycle according to the present invention. 1 is a rear left side view of a motorcycle according to the present invention. 1 is a rear right side view of a motorcycle according to the present invention. 1 is a bottom view for explaining an exhaust device for a motorcycle according to the present invention. 1 is a plan view illustrating an exhaust device for a motorcycle according to the present invention. 1 is a perspective view illustrating an exhaust device for a motorcycle according to the present invention. It is a top view of the chamber storage part with which the motorcycle concerning the present invention is equipped. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. FIG. 9 is a sectional view taken along line 9-9 in FIG. 8. FIG. 10 is a sectional view taken along line 10-10 in FIG. 8. It is the 11-11 line sectional view of FIG. It is another Example figure of FIG. It is another Example figure of FIG.

  Hereinafter, embodiments of the present invention will be described in detail. In the drawings and examples, “up”, “down”, “front”, “rear”, “left”, and “right” respectively indicate directions viewed from the driver who rides the motorcycle. The drawings are viewed in the direction of the reference numerals.

First, Embodiment 1 of the present invention will be described with reference to the drawings.
In FIG. 1, a motorcycle 10 has a front fork 12 attached to a head pipe 11 so as to be steerable, and main frames 13 and 14 (only the reference numeral 13 on the front side is shown) extend from the head pipe 11 to the left and right. The engine 15 is attached to the main frames 13 and 14, and a pivot shaft 18 is provided on the rear portion 16 of the engine so as to penetrate left and right. A swing arm 21 is attached to the pivot shaft 18 so as to freely swing up and down. This is a vehicle in which the rear frame 22 is extended from the rear. A body frame 20 is constituted by the main frames 13 and 14 and the rear frame 22 extending from the rear of the main frames 13 and 14.

The front fork 12 has a front wheel 26 rotatably attached to the lower end and a steering handle 27 attached to the upper end. The front fender 28 covers the front wheel 26 with a front fender 28.
The engine 15 includes a crankcase 31, a front bank 33 extending obliquely upward and forward from the crankcase 31, and a rear bank extending obliquely upward and rearward from the crankcase 31 and at an angle of 90 ° with respect to the front bank 33. , A front bank 33 is a two-cylinder, and a rear bank 34 is a two-cylinder V-type V-type engine.

  The front bank 33 includes a front cylinder block 35, a front cylinder head 36 attached above the front cylinder block 35, and a front head cover 37 that covers the front cylinder head 36. Similarly, the rear bank 34 includes a rear cylinder block 45, a rear cylinder head 46 attached above the rear cylinder block 45, and a rear head cover 47 that covers the rear cylinder head 46. An oil pan 48 covers the lower part of the crankcase 31.

The swing arm 21 has a rear wheel 25 rotatably attached to the rear end via an axle 19, and a lower end of the rear cushion unit 26 is attached to a front portion of the swing arm 21 via a link mechanism 55. The upper end of the rear cushion unit 26 is attached to the main frames 13 and 14 side. The link mechanism 55 is also attached to an underframe 56 provided at the rear portion of the engine 15.
In the figure, 57 is a main seat supported by the rear frame 22, 58 is a pillion seat supported by the rear frame 22, 61 is a front cowl, 62 is a center cowl, 63 is a lower cowl, 64 is a rear cowl, 65 is a fuel tank, 66, Reference numeral 66 (only the reference numeral 66 on the front side of the figure is shown) is a pillion step holder, 67 is a chain cover, 68 is a rear fender, 69 is a chain, and 70 is a sprocket.

2 and 3, first and third suspension parts 71 to 73 to which the engine 15 is attached are provided on the left and right main frames 13 and 14 as constituent members of the vehicle body frame 20.
A pivot shaft support portion 74 that supports the above-described pivot shaft 18 is formed in the rear portion 16 of the engine, and an underframe 56 that supports an exhaust pipe 77 including an exhaust passage 76 described later near the pivot shaft support portion 74. Underframe support portions 78, 78 to which are attached are provided. The underframe 56 is supported not only by the underframe support portion 78 but also by the pivot shaft support portion 74.

  Rear frames 22 extend rearward and obliquely upward from the rear portions of the left and right main frames 13, 14, and these rear frames 22 are upper rear frames 23, 23 (only the reference numeral 23 on the front side in the figure is shown) and a lower portion. The rear frames 24 and 24 (only the reference numeral 24 on the front side of the figure is shown), and the rear end portions 23a and 23a of the upper rear frame and the rear end portions 24a and 24a of the lower rear frame are connected to each other. Reference numerals 79 and 79 (only the reference numeral 79 on the front side of the drawing) are reinforcing members. 51 is a dynamo cover, 52 is a clutch cover.

Hereinafter, the configuration of the engine exhaust device will be described.
2 to 4, left and right front exhaust pipes 81 and 82 as components of the exhaust passage 76 are extended from the front cylinder head 36, and the left and right two front exhaust pipes 81 and 82 are moved rearward. After extending, the front collecting portion 83 is connected to the rear ends of the two left and right front exhaust pipes 81 and 82 and joined together, and the first catalyst 85 and the second catalyst 86 are connected to the rear end portion 84 of the front collecting portion. It connected to the chamber storage part 87 to be stored. The left and right front exhaust pipes 81 and 82 pass below the engine 15.

Further, left and right rear exhaust pipes 91 and 92 as components of the exhaust passage 76 are extended from the rear cylinder head (reference numeral 46 in FIG. 1), and the left and right rear exhaust pipes 91 and 92 are temporarily connected. After extending to the right side of the vehicle, it extends downward, connects the rear collecting portion 93 to the rear ends of the two left and right rear exhaust pipes 91, 92 and joins them, and is downstream of the rear collecting portion 93. The rear end portion 94 was connected to a chamber housing portion 87 in which the first catalyst 85 and the second catalyst 86 were housed. The left and right rear exhaust pipes 91 and 92 pass behind the engine 15.
The rear assembly portion 93 includes a rear extending portion 97 extending from the rear upper portion to the front lower portion, and a curved portion 98 connected to the downstream side of the rear extending portion 97 and having a substantially U shape.

  A bypass pipe 102 through which exhaust gas passes between a rear extending portion 97 constituting the rear collecting portion 93 and a diameter expanding portion 101 provided on the upstream side of the second catalyst 86 in the chamber storage portion 87. Has been passed. A bypass passage 103 is formed in the bypass pipe 102, and a valve unit 104 is interposed in the bypass passage 103.

  The first catalyst 85 is disposed downstream of the branch portion 106 where the bypass passage 103 branches, and upstream of the junction portion 107 where the bypass passage 103 joins and is disposed in the chamber housing portion 87 constituting the exhaust passage.

  The chamber storage portion 87 to which the front collection portion 83 and the rear collection portion 93 are connected is continuous with the first catalyst storage portion 111 in which the first catalyst 85 is stored, and behind the first catalyst storage portion 111. And a second catalyst storage portion 112 in which the second catalyst 86 is stored, and an outlet portion 113 through which the purified exhaust gas passes is provided on the downstream side of the chamber storage portion 87. A connecting pipe 114 extends from the connecting pipe 114, and a silencer 115 is connected to the connecting pipe 114.

The exhaust gas passes through the front exhaust pipes 81 and 82, the front collecting portion 83, the rear exhaust pipes 91 and 92, the rear collecting portion 93, and the chamber housing portion 87 extending from the engine 15 described above. These members are collectively referred to as an exhaust passage 76.
The connecting pipe 114 extending rearward from the rear part 117 of the chamber housing part and the silencer 115 connected to the connecting pipe 114 are collectively referred to as a rear exhaust passage 76R. The rear exhaust passage 76R is attached to a muffler stay 118 that extends downward from the right lower rear frame 24 that constitutes the body frame 20 side.

  A chamber housing portion 87 is provided with a chamber mounting portion 121 at an upper portion of the first catalyst housing portion 111, and this chamber mounting portion 121 is provided on the side of the vehicle body frame (reference numeral 20 in FIG. 2). 56 is attached.

  That is, the motorcycle 10 includes a front exhaust pipe 81 and 82 as an exhaust passage that extends rearward and passes through the lower side of the engine 15 and through which the exhaust gas passes, and a body frame in the middle of the front exhaust pipe 81 and 82. 20 is provided with a chamber accommodating portion 87 in which a first catalyst 85 disposed below 20 and a second catalyst 86 disposed adjacent to the downstream side of the first catalyst 85 are accommodated.

  The height (H10) of the upper surface 123 of the first catalyst from the ground is set lower than the height (H20) of the upper surface 124 of the second catalyst from the ground, and the upper surface 125 of the first catalyst storage unit from the ground. The height (H1) is set lower than the height (H2) from the ground of the upper surface 126 of the second catalyst storage unit.

  A curved portion 98 provided in the rear collecting portion 93 through which the exhaust gas of the rear cylinder head 46 merges and passes is disposed below the engine 15. Since the curved portion 98 is disposed below the engine 15, the rear collecting portion 93 that forms the exhaust passage with the engine 15 can be compactly disposed.

  The engine 15 is mounted on a vehicle, and the left and right rear exhaust pipes 91 and 92 as components of the exhaust passage extend from the rear surface of the engine (reference numeral 17 in FIG. 1). That is, the exhaust passage 76 extending from the cylinder provided in the front bank 33 and the cylinder provided in the rear bank 34 is connected to the common catalyst 131, and the curved portion 98 and the bypass passage 103 are connected to the exhaust passage of the rear bank 34. And the rear exhaust pipes 91 and 92 are provided in a rear collecting portion 93. The rear exhaust pipes 91 and 92 and the rear collecting portion 93 as exhaust passages extending from the rear bank 34 are less likely to be hit by running wind and easily maintained by the front bank 33 and the like disposed at the front. By providing the curved portion 98 and the bypass passage 103 on the rear side, the catalyst is more easily activated. That is, since the traveling wind hardly hits the rear exhaust pipes 91 and 92, the cooling of the rear exhaust pipes 91 and 92 by the traveling wind can be suppressed, and the activation of the catalyst can be further promoted.

5 and 6, the engine exhaust device 130 exhausts into the exhaust passage 76 through which the exhaust gas of the engine (reference numeral 15 in FIG. 1) passes and the chamber housing portion 87 arranged in the middle of the exhaust passage 76. And a catalyst 131 for purifying the gas. A part of the rear collecting portion 93 provided in the exhaust passage 76 is a substantially U-shaped curved portion 98, and the catalyst is disposed downstream of the curved portion 98. A first catalyst 85 that constitutes one of 131 is disposed and is connected between the upstream of the curved portion 98 and the downstream of the curved portion 98 and upstream of the second catalyst 86 at a distance shorter than the passage length of the curved portion 98. A bypass passage 103 is provided. That is, the bypass passage 103 is connected to the enlarged-diameter portion 101 that is the chamber housing portion 87 and is provided between the first catalyst 85 and the second catalyst 86.
In this embodiment, the merging portion of the bypass passage is connected between the first catalyst and the second catalyst, but may be connected to the chamber storage portion and upstream of the first catalyst. Absent.

Hereinafter, the detailed structure of the chamber storage portion 87 in which the first catalyst 85 and the second catalyst 86 are stored will be described.
7 and 8, the catalyst unit 132 includes a first catalyst storage unit 111 that stores the first catalyst 85, a second catalyst storage unit 112 that stores the second catalyst 86, a first catalyst storage unit 111, and a first catalyst storage unit 111. A diameter-expanding portion 101 that expands in the downstream direction is provided between the two catalyst storage portions 112.

A spacer 136 that is formed in a ring shape on the rear outer peripheral portion 135 of the first catalyst and that holds the first catalyst 85 is provided. The spacer 136 is fixed to the first catalyst storage portion 111, and is attached to the front outer peripheral portion 137 of the first catalyst. A first mesh spacer 141 for holding is provided.
A plurality of first welding holes for attaching the first catalyst 85 fixed to the spacer 136 to the first catalyst housing portion 111 at a position corresponding to the spacer 136 serving as a holding portion of the first catalyst 85 in the first catalyst housing portion 111. 143... (... indicates a plurality. The same applies hereinafter) is formed, and the first catalyst 85 is fixed using these first welding holes 143.

A holding guide portion 146 is provided on the front outer peripheral portion 147 of the second catalyst, the guide portion 146 is fixed to the second catalyst storage portion 112, and a second mesh spacer for holding is provided on the rear outer peripheral portion 145 of the second catalyst. 142 is provided.
In the second catalyst storage portion 112, a plurality of second catalysts that stop the second catalyst 86 including the guide portion 146 in the second catalyst storage portion 112 at a position corresponding to the guide portion 146 serving as a holding portion of the second catalyst 86. Weld holes 144 are formed, and the second catalyst 86 is fixed using these second weld holes 144.

In FIG. 9, a holding first mesh spacer 141 is provided between the front outer peripheral portion 137 of the first catalyst and the first catalyst storage portion 111, and the first catalyst 85 has a major axis along the vehicle width direction. It has an elongated oval cross section.
The first catalyst storage unit 111 has an oval cross section, and is formed by abutting the first upper half 151 and the first lower half 152 and welding them together.

  In FIG. 10, the spacer 136 is fixed to the outer peripheral portion 138 of the first catalyst. A chamber attachment portion 121 is attached to the upper surface 125 of the first catalyst storage portion. In the figure, reference numeral 154 denotes a welded portion for fixing the space between the spacer 136 and the first catalyst housing portion 111.

  In FIG. 11, the guide part 146 attached to the outer peripheral part of the second catalyst 86 is fixed to the outer peripheral part 148 of the second catalyst. In the figure, 155... Are welded portions that adhere between the guide portion 146 and the second catalyst housing portion 112.

  Referring also to FIGS. 5 to 7, the catalyst 131 includes a first catalyst 85 and a second catalyst 86 provided downstream of the first catalyst 85, and the first catalyst 85 is a second catalyst. 86, the rear extension portion 97 constituting the rear connecting portion 157 as the exhaust passage and the branching portion 106 where the bypass passage 103 branches, and the enlarged diameter portion 101 constituting the exhaust passage and the bypass. It arrange | positions upstream of the confluence | merging part 107 where the channel | path 103 merges.

The catalyst 131 includes the first catalyst 85 and the second catalyst 86, and the exhaust gas is purified by both the first catalyst 85 and the second catalyst 86, so that the purification performance can be improved.
In addition, since the volume of the first catalyst 85 is smaller than the volume of the second catalyst 86, the heat capacity of the first catalyst 85 can be reduced, and the activation of the first catalyst 85 can be promoted.

  Since the diameter of the bypass passage 103 is smaller than the diameter of the curved portion 98 of the exhaust passage, the surface area of the bypass passage 103 can be reduced, and as a result, the amount of radiant heat that escapes from the bypass passage 103 into the air is reduced. At the same time, the heat capacity of the bypass passage itself can be lowered, and as a result, the temperature of the exhaust gas passing through the bypass passage 103 can be kept high.

The operation of the above-described motorcycle and its exhaust device will be described next.
A bypass passage 103 connected between the upstream side of the bending portion 98 and the downstream side of the bending portion 98 and upstream of the catalyst 131 is connected at a distance shorter than the passage length of the bending portion 98.

  Conventionally, in order to activate the catalyst at an early stage, there are cases where a corresponding means is separately utilized by energizing or heating the metal catalyst carrier of the catalyst. However, such means has a problem that it tends to increase the cost of the exhaust device.

In this regard, in the present invention, it is only necessary to provide a bypass passage 103 shorter than the passage length of the bending portion 98 between the upstream side of the bending portion 98 and the downstream side of the bending portion 98 and upstream of the catalyst 131. Therefore, the cost increase of the exhaust device 130 can be suppressed. In addition, since the exhaust gas can pass through the bypass passage 103 and reach the second catalyst 86 constituting the catalyst at a short distance, the high-temperature gas can be applied to the catalyst. Since the high-temperature gas can be applied to the catalyst, the second catalyst 86 can be activated early. Therefore, it is possible to activate the second catalyst 86 at an early stage while suppressing an increase in the cost of the exhaust device 130.
Furthermore, since the exhaust passage 76 includes the curved portion 98 and has a sufficient length, there is an advantage that the optimum output characteristics of the engine 15 can be easily obtained.

  Referring to FIGS. 2, 4, and 9, first catalyst 85 has an oval cross section in which the long axis extends along the vehicle width direction, so that the cross sectional area of first catalyst 85 is sufficient. The height of the first catalyst 85 can be suppressed while ensuring a large capacity of the first catalyst 85. In addition, the chamber attachment portion 121 is attached to the upper portion of the first catalyst storage portion 111, and the height (H1) of the upper surface 125 of the first catalyst storage portion is disposed adjacent to the downstream side of the first catalyst. It is set lower than the height (H2) of the upper surface 126 of the second catalyst storage portion. And the chamber attachment part 121 is attached to the upper surface 125 of the 1st catalyst storage part by which height is set lower than the height (H2) of the upper surface 126 of a 2nd catalyst storage part. Since the chamber mounting portion 121 is disposed in a region where there is a difference between the height of the upper surface 125 of the first catalyst and the height of the upper surface 126 of the second catalyst housing portion, the height of the first catalyst housing portion 111 from the ground ( The chamber accommodating portion 87 can be supported while keeping H10) high.

Therefore, even when the size of the first catalyst 85 is increased, the height (H10) of the first catalyst 85 can be suppressed, and the ground height (H1) of the first catalyst storage unit 111 can be increased. Therefore, the minimum ground clearance (HL) of the vehicle can be easily increased.
A rear exhaust passage 76 extending to the rear portion 117 of the chamber housing portion is attached to the vehicle body frame 20 side. The chamber storage portion 87 includes a chamber mounting portion 121 provided at the upper part of the first catalyst storage portion 111 that constitutes the front portion 116 of the chamber storage portion, and a muffler that constitutes a rear exhaust passage 76 disposed behind the chamber storage portion 87. It is supported by a muffler stay 118 to which the container 115 is attached. That is, the chamber storage portion 87 is attached to the body frame 20 at the front and rear portions. For this reason, it becomes possible to attach the chamber accommodating part 87 more reliably to the vehicle body side.

Furthermore, the height (H10) of the upper surface 125 of the first catalyst from the ground (H10) is the height (H0) of the upper surface 161 of the front collecting pipe as an exhaust passage connected immediately before the first catalyst housing 111 from the ground. ), It is possible to suppress the downward bulging of the first catalyst storage unit 111. In addition, since the first catalyst 85 is disposed behind the oil pan 48 swelled below the engine 15, the capacity of the oil pan 48 can be sufficiently secured.
As a result, it is possible to ensure a sufficient cross-sectional area of the catalyst 131 while ensuring a sufficient capacity of the oil pan 48 and to secure a minimum ground clearance (HL) of the vehicle to a sufficient height.

  Further, as described above, the engine 15 includes four cylinders, and the exhaust passages 76... Extend from these cylinders, and a plurality of exhaust passages 76.・ Are connected side by side in the vehicle width direction. Since the exhaust passages 76 are arranged in the vehicle width direction, the height direction dimension of the exhaust passages 76 can be suppressed, and the minimum ground clearance (HL) is easily secured.

Next, a second embodiment of the present invention will be described with reference to the drawings.
12 to 13, the main difference from the first embodiment is that the height (H11) from the ground surface of the lower surface 163 of the first catalyst storage unit in which the first catalyst 85 is stored and the second catalyst 86 are stored. The height (H21) from the ground surface of the lower surface 164 of the second catalyst storage portion is set to the same height (H11 = H21), and there is no other significant difference.

The chamber attachment portion 121 is attached to the upper surface 125 of the first catalyst storage portion, and the height (H1) of the upper surface 125 of the first catalyst storage portion is disposed adjacent to the downstream side of the first catalyst storage portion 111. It is set lower than the height (H2) of the upper surface 126 of the second catalyst storage portion.
The height (H11) of the lower surface 163 of the first catalyst storage unit is the same as the height (H21) of the lower surface 164 of the second catalyst storage unit disposed adjacent to the downstream side of the first catalyst storage unit 111. Since it is set, the minimum ground height (HL) of the vehicle can be increased while increasing the capacity of the catalyst.

  Although the present invention is applied to a motorcycle in the embodiment, it can also be applied to a tricycle and can be applied to a general straddle-type vehicle. The first catalyst has an oval cross section, but may be an ellipse as long as the cross section has a greater width than the height.

  The present invention is suitable for a motorcycle in which a first catalyst is provided in the exhaust passage and a second catalyst is provided downstream of the first catalyst.

  DESCRIPTION OF SYMBOLS 10 ... Motorcycle, 15 ... Engine, 20 ... Body frame, 48 ... Oil pan, 76 ... Exhaust passage, 76R ... Rear exhaust passage, 85 ... First catalyst, 86 ... Second catalyst, 87 ... Chamber storage, 111 ... 1st catalyst accommodating part, 112 ... 2nd catalyst accommodating part, 121 ... Chamber attachment part.

Claims (7)

A body frame (20), an engine (15) attached to the body frame (20), and the engine exhaust passage extends rearward passing through the exhaust gas through the lower (15) (76), this A first catalyst (85) disposed in the middle of the exhaust passage (76) and below the vehicle body frame (20) , and a middle of the exhaust passage (76 ) and downstream of the first catalyst (85) . A motorcycle provided with a second catalyst (86) disposed adjacent to the side,
Wherein the first catalyst (85) and the second catalyst (86) is accommodated in the chamber housing portion (87), the chamber mounting portion (121 for mounting the chamber housing portion (87) on a side of the body frame (20) ) is mounted above the first catalyst (85),
The chamber storage part (87) includes a first catalyst storage part (111) in which the first catalyst (85) is stored, and a second catalyst storage part (112) in which the second catalyst (86) is stored. Consists of
The chamber storage portion (87) has a diameter-expanding portion (101) that expands in the downstream direction between the first catalyst storage portion (111) and the second catalyst storage portion (112).
The chamber attachment part (121) is attached to an upper part of the first catalyst storage part (111),
The first catalyst (85) has an oval cross section in which a long axis extends in the vehicle width direction, and the height of the upper surface (123) of the first catalyst (85) from the ground is 2 is set lower than the height of the upper surface (124) of the catalyst (86) from the ground,
The height of the upper surface (125) of the first catalyst storage unit (111) from the ground is set lower than the height of the upper surface (126) of the second catalyst storage unit (112) from the ground. Motorcycle characterized by Claims wherein the extended the rear exhaust passage from the rear to the rear of the chamber housing portion (87) (76R), the rear exhaust passage (76R) is characterized in that attached to the side of the body frame (20) Item 2. The motorcycle according to item 1. The height of the upper surface (125) of the first catalyst storage part (111) from the ground is the exhaust passage connected to the exhaust passage (76) immediately before the first catalyst storage part (111). (76) is set higher than the height from the ground on the upper surface,
The said 1st catalyst (85) is arrange | positioned back rather than the oil pan (48) with which the said engine (15) bulges below, and is provided. Motorcycle. The engine (15) includes a plurality of cylinders, an exhaust passage (76) extending from the cylinders, and a plurality of exhaust passages (76 ) forward of the first catalyst housing portion (111) of the chamber housing portion (87) . ) is claim 1, characterized in that it is connected in line in the vehicle width direction, claim 2 or any one motorcycle according to claim 3. The exhaust passage (76) allows exhaust gas to pass through the chamber housing (87) separately from a path connected to the first catalyst housing (111) from the front of the first catalyst housing (111). The motorcycle according to claim 4, further comprising a bypass passage (103). The joining portion between the bypass passage (103) and the chamber housing portion (87) is connected between the first catalyst (85) and the second catalyst (86). The described motorcycle. The axis of the first catalyst (85) and the axis of the second catalyst (86) are arranged on the front and rear sides of the vehicle so as to be substantially on the same line. Motorcycle according to the item.

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