JP2016070268A - Exhaust device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an exhaust muffler by reducing a dead space in the exhaust muffler even when a supporting stay is accommodated in the exhaust muffler, in an exhaust device of an internal combustion engine in which a catalyst converter is accommodated in the exhaust muffler, and a downstream end of an exhaust pipe connected to an engine body at its upstream end to guide exhaust gas, is connected to the catalyst converter.SOLUTION: A supporting stay 42 for slidably holding a catalyst converter 36 disposed in an exhaust muffler 35 at a position eccentric from a center axis CM of the exhaust muffler 35, is formed separately from an inner wall surface 38a of the exhaust muffler 35 in a state of inhibiting circulation of exhaust gas within a prescribed peripheral range including a part where a distance between the catalyst converter 36 and the inner wall surface 38a of the exhaust muffler 35 becomes shortest, and permitting the circulation of the exhaust gas around the supporting stay 42 in a range excluding the prescribed peripheral range.SELECTED DRAWING: Figure 3

Description

  The present invention provides an internal combustion engine in which a catalytic converter is housed in an exhaust muffler formed in a cylindrical shape, and an upstream end is connected to an engine body so as to guide exhaust gas, and a downstream end of an exhaust pipe is connected to the catalytic converter. The present invention relates to an exhaust system of an engine.

  Such an exhaust device is known from Patent Document 1, in which a support stay that supports a catalytic converter in an exhaust muffler divides the inside of the exhaust muffler by a support stay, and the inner wall surface of the exhaust muffler. It is fixed to.

JP 2013-72396 A

  However, in the one disclosed in Patent Document 1, the space in the exhaust muffler from the exhaust muffler inlet side to the support stay becomes a dead space, which leads to an increase in the size of the exhaust muffler.

  The present invention has been made in view of such circumstances, and even if a support stay that supports the catalytic converter and is fixed to the inner wall surface of the exhaust muffler is accommodated in the exhaust muffler, the dead space in the exhaust muffler is reduced. It is an object of the present invention to provide an exhaust device for an internal combustion engine that enables downsizing of an exhaust muffler.

  In order to achieve the above object, the present invention provides a downstream end of an exhaust pipe in which a catalytic converter is accommodated in an exhaust muffler formed in a cylindrical shape, and an upstream end is connected to an engine body so as to guide exhaust gas. In the exhaust system for an internal combustion engine connected to the catalytic converter, the catalytic converter is disposed in the exhaust muffler at a position eccentric from the central axis of the exhaust muffler, and a support stay that holds the catalytic converter slidably. However, although the portion between the catalytic converter and the inner wall surface of the exhaust muffler includes a portion where the distance is the shortest, the circulation of the exhaust gas is prevented in a predetermined circumferential range set in the circumferential direction of the catalytic converter, In a range excluding a predetermined range in the circumferential direction, the exhaust muffler is separated from the inner wall surface so as to allow the exhaust gas to flow around the support stay. It is the the first, characterized in that.

  In addition to the configuration of the first feature, the second feature of the present invention is that the predetermined circumferential range is set to be less than a half circumference of the catalytic converter.

  In addition to the configuration of the first or second feature, the present invention provides a mounting portion having a non-circular cross-sectional shape so that the support stay is welded to the inner wall surface of the exhaust muffler, and the catalyst The converter is formed in a cylindrical shape so as to be slidable, and is integrally formed with a holding portion that is spaced apart from the mounting portion in a direction along the axis of the catalytic converter. Is the third feature.

  The present invention is characterized in that, in addition to the configuration of the third feature, the support stay is formed in a shape opened in a bowl shape toward the upstream side of the catalytic converter.

  According to the present invention, in addition to the configuration of the third or fourth feature, the attachment portion has an arc shape along the inner wall surface of the exhaust muffler on a projection view on a plane orthogonal to the central axis of the exhaust muffler. A welded portion formed on the inner wall surface and welded to the inner wall surface, an arc portion formed in an arc shape so as to cover a half circumference of the catalytic converter on the side opposite to the welded portion with respect to the catalytic converter, A fifth feature is that it is formed to have both ends of the welded portion along the circumferential direction of the exhaust muffler and a pair of connecting portions connecting both ends of the arc portion along the circumferential direction of the catalytic converter. .

  In addition to the configuration of the fifth feature, the present invention is characterized in that a gap is formed between the semicircular portion of the mounting portion and the outer periphery of the catalytic converter.

  According to the seventh aspect of the present invention, in addition to any one of the first to sixth features, a seventh expansion chamber is formed in the exhaust muffler so as to accommodate the catalytic converter. Features.

  According to the present invention, in addition to any of the configurations of the first to seventh features, the catalytic converter is disposed in the exhaust muffler at a position eccentrically upward from the central axis of the exhaust muffler and is mounted on a vehicle. The exhaust muffler is disposed below the engine body, and a tail pipe for discharging exhaust gas from the exhaust muffler is disposed below the catalytic converter in a side view while being offset from the central axis of the exhaust muffler. In this manner, the exhaust muffler is provided with the eighth feature.

  In addition to the configuration of the eighth feature, the present invention provides a muffler suspension bracket fixed to the engine body so as to support the exhaust muffler, and a fixing bracket for fixing a vehicle component to the engine body. The ninth feature is that they are integrated with each other.

  According to the first aspect of the present invention, the catalytic converter is disposed at a position eccentric from the central axis of the exhaust muffler, and the support stay that slidably holds the catalytic converter is exhausted in a predetermined range in the circumferential direction of the catalytic converter. Although the gas flow is blocked, the support stay is formed away from the inner wall surface of the exhaust muffler so as to allow the exhaust gas to flow in a range excluding the predetermined range in the circumferential direction. The catalytic converter can be slidably held while reducing the dead space in the exhaust muffler while allowing the exhaust gas to flow through the part. Even if the support stay is accommodated in the exhaust muffler, the exhaust muffler is small Can be realized.

  Further, according to the second feature of the present invention, the predetermined range in the circumferential direction is less than a half of the catalytic converter. Therefore, the portion that prevents the exhaust gas from flowing around the support stay is reduced, and the dead space in the exhaust muffler is reduced. The exhaust muffler can be further downsized.

  According to the third feature of the present invention, the support stay has a non-circular cross-sectional shape and is attached to the inner wall surface of the exhaust muffler and a cylindrical shape that slidably holds the catalytic converter. Since the holding portion is integrally formed and the mounting portion and the holding portion are spaced apart in the direction along the axis of the catalytic converter, it is easy to integrally form the mounting portion and the holding portion to form the support stay. is there.

  According to the fourth feature of the present invention, since the support stay is open in a bowl shape toward the upstream side of the catalytic converter, the rigidity of the support stay can be ensured.

  According to the fifth feature of the present invention, the mounting portion of the support stay is a circular arc-shaped welded portion along the inner wall surface of the exhaust muffler on the projection onto the plane orthogonal to the central axis of the exhaust muffler, and the catalyst It is formed to have a circular arc part covering the half circumference of the converter and a pair of connecting parts that linearly connect both ends of the welded part and both ends of the arc part, and the welded part is welded to the inner wall surface of the exhaust muffler. Therefore, the catalytic converter can be held while facilitating the welding of the support stay to the inner wall surface of the exhaust muffler.

  According to the sixth aspect of the present invention, since there is a gap between the arc portion of the mounting portion and the outer periphery of the catalytic converter, the resistance due to friction between the catalytic converter and the support stay is reduced during the thermal expansion of the catalytic converter, and the catalyst The thermal expansion of the converter is not hindered.

  According to the seventh feature of the present invention, since only one expansion chamber is formed in the exhaust muffler, the dead space is reduced while using the entire exhaust muffler as the expansion space, thereby reducing the size of the exhaust muffler. Can be achieved.

  According to the eighth aspect of the present invention, the exhaust muffler disposed below the engine body mounted on the vehicle is provided with a tail pipe that exhausts exhaust gas from the exhaust muffler. The exhaust pipe connected to the catalytic converter is located closer to the upper half of the exhaust muffler because it is located below the catalytic converter offset upward from the central axis of the muffler and offset downward from the central axis of the exhaust muffler. It is possible to secure the distance between the exhaust pipe and the ground by arranging it biased.

  Furthermore, according to the ninth feature of the present invention, the muffler suspension bracket fixed to the engine body for supporting the exhaust muffler is integrated with the fixing bracket for fixing the vehicle component to the engine body. By fixing the exhaust muffler and the vehicle component fixing points to the engine body, it is possible to reduce the processing of the mounting part on the engine body side and suppress the reduction in rigidity of the engine body.

1 is a left side view of a motorcycle. FIG. 2 is an enlarged vertical side view of a portion indicated by an arrow 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 3 is a perspective view of the exhaust muffler with a part thereof broken, as viewed from the direction of arrow 4 in FIG. 2. It is the perspective view seen from the 5 arrow direction of FIG.

  Hereinafter, 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 as viewed from the occupant riding the motorcycle.

  First, in FIG. 1, a body frame F of the motorcycle includes a head pipe 13 that supports a front fork 11 for pivotally supporting a front wheel WF at a lower end portion and a steering bar handle 12 for steering, and the head pipe 13 A main frame 14 extending downwardly from the rear, an upper frame 15 disposed above the main frame 14 and extending rearward from the head pipe 12, and a pair of left and right extending downward from the rear end of the main frame 14 A pivot frame 16, a pair of left and right seat frames 17 connected to the rear end portion of the upper frame 15 and extending rearward, and extending rearward from the upper end portions of the pair of left and right pivot frames 16, and the rear end portion of the pair. And a pair of left and right rear frames 18 connected to the rear portion of the seat frame 17.

  The pivot frame 16 supports a front end portion of a swing arm 19 around which a rear wheel WR is suspended so as to swing up and down via a support shaft 20. A rear cushion unit 21 is provided between the rear portion of the swing arm 19 and the seat frame 17.

  The engine body 22 of the internal combustion engine E that exerts power for driving the rear wheels WR is supported by the main frame 14 and the pivot frame 16 of the vehicle body frame F with the cylinder axis C tilted forward until it becomes substantially horizontal. Rotational power from the internal combustion engine E is transmitted to the rear wheel WR via a power transmission mechanism 24 having an endless drive chain 23.

  A fuel tank 25 disposed above the engine main body 22 is supported on the upper frame 15 of the vehicle body frame F, and a tandem type riding seat 26 disposed behind the fuel tank 25 includes the fuel tank 25. It is supported by the seat frame 17.

  The intake device 28 of the internal combustion engine E is connected to an intake pipe 29 having a downstream end connected to an upper side wall of a cylinder head 27 constituting a part of the engine body 22, and to an upstream end of the intake pipe 29. A vaporizer 30, an air cleaner 31 disposed behind the vaporizer 30, and a connecting tube 32 connecting the vaporizer 30 and the air cleaner 31.

  The exhaust device 33 of the internal combustion engine E is connected to an exhaust pipe 34 connected to the lower side wall of the cylinder head 27, an exhaust muffler 35 disposed below the engine body 22, and the exhaust pipe 34. Thus, a catalytic converter 36 accommodated in the exhaust muffler 35 is provided.

  2 to 4, the exhaust muffler 35 includes a cylindrical case 38, an upstream end plate 39 that closes one end of the case 38, and a downstream end plate that closes the other end of the case 38. 40, and a single expansion chamber 41 is formed in the exhaust muffler 35.

  The catalytic converter 36 having a circular outer cross-sectional shape is disposed at a position eccentric from the central axis CM of the exhaust muffler 35. In this embodiment, the central axis CC of the catalytic converter 36 is accommodated in the exhaust muffler 35 so as to be above the central axis CM of the exhaust muffler 35 and in parallel with the central axis CC. The downstream end of the exhaust pipe 34 is connected to the upstream end of the catalytic converter 36 that penetrates the upstream end plate 39.

  The catalytic converter 36 is slidably held by a support stay 42. The support stay 42 is welded to the inner wall surface 38a of the case 38 of the exhaust muffler 35 so as to have a non-circular cross-sectional shape. A mounting portion 42a having a circular cross section so as to slidably hold the catalytic converter 36, and a holding portion 42b spaced from the mounting portion 42a in a direction along the central axis CC of the catalytic converter 36. In this embodiment, the holding portion that is spaced apart from the mounting portion 42a and the downstream end plate 40 side in the direction along the central axis CC of the catalytic converter 36 is formed. 42b are integrally connected to each other via a connecting cylinder portion 42c, and open in a bowl shape toward the upstream side of the catalytic converter 36. It is formed in a shape.

  The mounting portion 42a is formed in an arc shape along the inner wall surface 38a of the exhaust muffler 35 as clearly shown in FIG. 3 on a projection view onto a plane orthogonal to the central axis CC of the exhaust muffler 35. A welded portion 42aa that is welded to a plurality of locations on the inner wall surface 38a, and an arc that is formed in an arc shape so as to cover a half circumference of the catalytic converter 36 on the opposite side of the welded portion 42aa with respect to the catalytic converter 36. A portion 42ab and a pair of connecting portions 42ac connecting both ends of the welded portion 42aa along the circumferential direction of the exhaust muffler 35 and both ends of the arc portion 42ab along the circumferential direction of the catalytic converter 36 are formed. Is done.

  The welded portion 42aa is welded to the inner wall surface 38a at a portion where the distance between the catalytic converter 36 and the inner wall 38a of the exhaust muffler 35 is shortest, and is centered on the central axis CC of the catalytic converter 36. It is formed in an arc shape in the range of the central angle α.

  Such a support stay 42 has a portion where the distance between the catalytic converter 36 and the inner wall surface 38a of the exhaust muffler 35 is the shortest on the projection onto the plane orthogonal to the central axis CM of the exhaust muffler 35. Including the circumferential predetermined range (the range of the central angle α) set in the circumferential direction of the catalytic converter 36 prevents the exhaust gas from flowing, but in the range excluding the circumferential predetermined range, Is formed away from the inner wall surface 38a of the exhaust muffler 35, and the predetermined range in the circumferential direction is set to be less than a half of the catalytic converter 36.

  Further, a gap 43 is formed between the arc portion 42ab of the mounting portion 42 and the outer periphery of the catalytic converter 36.

  The exhaust muffler 35 is provided with a tail pipe 44 that discharges exhaust gas from the exhaust muffler 35. The tail pipe 44 penetrates the end plate 40 on the downstream side so as to penetrate the end plate 40. And is disposed below the catalytic converter 36 in a side view while being offset from the central axis CM of the exhaust muffler 35.

  Referring also to FIG. 5, a muffler suspension bracket 46 that supports a mounting plate 47 fixed to the rear upper part of the exhaust muffler 35 is fixed to the bottom of the crankcase 45 in the engine body 22. The mounting plate 47 is fixed to the muffler suspension bracket 46 with bolts 48 and nuts 49.

  On the other hand, a first fixing bracket 51 is fastened to the bottom of the crankcase 45 with a pair of bolts 53 and 54 to support a rod 49 as a vehicle component extending in the vehicle width direction. A second fixing bracket 52 disposed at a distance to the left side of the first fixing bracket 51 in the direction is fastened by a pair of bolts 55 and 56, and footrests 57 and 57 are attached to both ends of the rod 49. Is provided.

  Moreover, the muffler suspension bracket 46 is integrated with the first fixed bracket 51 by welding or the like, and the muffler suspension bracket 46 is fixed to the crankcase 45 via the first fixed bracket 51. .

  Next, the operation of this embodiment will be described. The catalytic converter 36 is disposed in the exhaust muffler 35 at a position eccentric from the central axis CM of the exhaust muffler 35, and supports the slidably holding the catalytic converter 36. The stay 42 circulates the exhaust gas in a predetermined range in the circumferential direction set in the circumferential direction of the catalytic converter 36 including a portion where the distance between the catalytic converter 36 and the inner wall surface 38a of the exhaust muffler 35 is the shortest. Although it is blocked, the support stay 42 is formed away from the inner wall surface 38a of the exhaust muffler 35 so as to allow the exhaust gas to flow around the support stay 42 in a range excluding the predetermined range in the circumferential direction. Makes it possible to distribute the exhaust gas in many parts around the catalytic converter 36 while reducing the dead space in the exhaust muffler 35. While fence can hold a catalytic converter 36 slidably, support stay 42 be housed in the exhaust muffler 35 can be miniaturized in the exhaust muffler 35.

  Moreover, since the predetermined range in the circumferential direction is set to be less than a half circumference of the catalytic converter 36, the portion that prevents the exhaust gas from flowing around the support stay 42 can be reduced, and the dead space in the exhaust muffler 35 can be reduced. Thus, the exhaust muffler 35 can be further downsized.

  Further, the support stay 42 is welded to the inner wall surface 38a of the exhaust muffler 35 so that the mounting portion 42a having a non-circular cross-sectional shape and the catalytic converter 36 are slidably held. And is formed so as to integrally have a holding portion 42b that is spaced apart from the mounting portion 42a in a direction along the central axis CC of the catalytic converter 36, so that the mounting portion 42a and the holding portion are formed. It is easy to form the support stay 42 by integrally molding 42b.

  In addition, since the support stay 42 is formed in a bowl-like shape toward the upstream side of the catalytic converter 36, the rigidity of the support stay 42 can be ensured.

  Further, the mounting portion 42a is formed in an arc shape along the inner wall surface 38a of the exhaust muffler 35 on a projection view on a plane orthogonal to the central axis CM of the exhaust muffler 35, and is welded to the inner wall surface 38a. A welded portion 42aa, an arc portion 42ab formed in an arc shape so as to cover a half circumference of the catalytic converter 36 on the opposite side to the welded portion 42aa with respect to the catalytic converter 36, and a circumferential direction of the exhaust muffler 35 And a pair of connecting portions 42ac that connect between both ends of the arc portion 42ab along the circumferential direction of the catalytic converter 36. Therefore, the inner wall surface 38a of the exhaust muffler 35 is formed. It is possible to hold the catalytic converter 36 while facilitating the welding of the support stay 42 to the base.

  Further, since the gap 43 is formed between the arc portion 42ab of the mounting portion 42a and the outer periphery of the catalytic converter 36, resistance due to friction between the catalytic converter 36 and the support stay 42 is reduced during thermal expansion of the catalytic converter 36, The thermal expansion of the catalytic converter 36 is not hindered.

  Further, since only one expansion chamber 41 is formed in the exhaust muffler 35 so as to accommodate the catalytic converter 36, the dead space can be reduced while using the entire exhaust muffler 35 as an expansion space. The exhaust muffler 35 can be downsized.

  The catalytic converter 36 is disposed in the exhaust muffler 35 at a position eccentric from the central axis CM of the exhaust muffler 35, and the exhaust muffler 35 is disposed below the engine body 22 mounted on the motorcycle. The tail pipe 44 for discharging exhaust gas from the exhaust muffler 35 is disposed below the catalytic converter 36 in a side view while being offset from the central axis CM of the exhaust muffler 35. Thus, the exhaust pipe 34 connected to the catalytic converter 36 is arranged so as to be biased toward the upper half of the exhaust muffler 35, and a distance between the exhaust pipe 34 and the ground can be secured.

  Further, a muffler suspension bracket 46 fixed to the engine main body 22 so as to support the exhaust muffler 35 is integrated with a fixing bracket 51 for fixing a rod 50 as a vehicle component to the engine main body 22. Therefore, the exhaust muffler 35 and the rod 50 can be fixed to the engine main body 22 in a common manner, and the processing of the mounting location on the engine main body 22 side can be reduced to suppress a reduction in rigidity of the engine main body 22.

  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.

22 ... Engine body 34 ... Exhaust pipe 35 ... Exhaust muffler 36 ... Catalytic converter 38a ... Exhaust muffler inner wall surface 41 ... Expansion chamber 42 ... Support stay 42a ... Installation Part 42aa ... welded part 42ab ... arc part 42ac ... connecting part 42b ... holding part 43 ... gap 44 ... tail pipe 46 ... muffler suspension bracket 50 ... vehicle configuration Rod 51, which is a part, fixed bracket CC, central axis CM of the catalytic converter, central axis of the exhaust muffler

Claims (9)

  A catalytic converter (36) is housed in an exhaust muffler (35) formed in a cylindrical shape, and a downstream end of an exhaust pipe (34) whose upstream end is connected to the engine body (22) so as to guide exhaust gas is In the exhaust system for an internal combustion engine connected to the catalytic converter (36), the catalytic converter (36) is located in the exhaust muffler (35) at a position eccentric from the central axis (CM) of the exhaust muffler (35). The support stay (42) that is disposed and slidably holds the catalytic converter (36) has a shortest distance between the catalytic converter (36) and the inner wall surface (38a) of the exhaust muffler (35). The exhaust gas is prevented from flowing in a predetermined circumferential range that is set in the circumferential direction of the catalytic converter (36), but in the range excluding the predetermined circumferential direction, the support stay is An exhaust system of an internal combustion engine, characterized in that the exhaust gas around is formed away from the inner wall surface of the exhaust muffler (35) so as to permit the circulating (38a) of the 42).   The exhaust system for an internal combustion engine according to claim 1, wherein the predetermined circumferential range is set to be less than a half of the catalytic converter (36).   A mounting portion (42a) having a non-circular cross-sectional shape so that the support stay (42) is welded to the inner wall surface (38a) of the exhaust muffler (35), and the catalytic converter (36). A holding portion (42b) which is formed in a cylindrical shape so as to be slidably held and is spaced apart from the mounting portion (42a) in a direction along the axis (CC) of the catalytic converter (36); The exhaust device for an internal combustion engine according to claim 1 or 2, wherein the exhaust device is integrally formed.   The exhaust system for an internal combustion engine according to claim 3, wherein the support stay (42) is formed in a shape opened in a bowl shape toward the upstream side of the catalytic converter (36).   The mounting portion (42a) is formed in an arc shape along the inner wall surface (38a) of the exhaust muffler (35) on a projection view on a plane orthogonal to the central axis (CM) of the exhaust muffler (35). The welded portion (42aa) welded to the inner wall surface (38a) and the catalytic converter (36) covering the half circumference of the catalytic converter (36) on the opposite side of the welded portion (42aa). The arc portion (42ab) formed in an arc shape, the both ends of the welded portion (42aa) along the circumferential direction of the exhaust muffler (35), and the arc portion along the circumferential direction of the catalytic converter (36) 5. The exhaust system for an internal combustion engine according to claim 3, wherein the exhaust system is formed to have a pair of connecting portions (42 ac) that connect both ends of (42 ab).   The exhaust system for an internal combustion engine according to claim 5, wherein a gap (43) is formed between the arc portion (42ab) of the attachment portion (42a) and the outer periphery of the catalytic converter (36).   The exhaust muffler (35), wherein only one expansion chamber (41) is formed so as to accommodate the catalytic converter (36). An exhaust system for an internal combustion engine as described.   The catalytic converter (36) is disposed in the exhaust muffler (35) at a position eccentrically upward from the central axis (CM) of the exhaust muffler (35), and the engine main body (22) mounted on the vehicle. The exhaust muffler (35) is disposed below, and a tail pipe (44) for discharging exhaust gas from the exhaust muffler (35) is viewed from the side while being offset from the central axis (CM) of the exhaust muffler (35). The exhaust system for an internal combustion engine according to any one of claims 1 to 7, wherein the exhaust system is provided in the exhaust muffler (35) so as to be disposed below the catalytic converter (36).   A muffler suspension bracket (46) fixed to the engine body (22) so as to support the exhaust muffler (35) is a fixing bracket for fixing a vehicle component (50) to the engine body (22). The exhaust device for an internal combustion engine according to claim 8, wherein the exhaust device is integrated with (51).

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