JP6493833B2 - Exhaust device for internal combustion engine - Google Patents

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. Has a mounting portion for mounting the support stay to the inner wall surface of the exhaust muffler, and the mounting portion is projected onto a plane orthogonal to the central axis of the exhaust muffler, and the exhaust muffler A support portion supported by an inner wall surface, and a circular arc shape is formed so as to cover a half circumference of the catalytic converter on the opposite side of the support portion with respect to the catalytic converter. The support stay is formed to have an arc portion and a pair of connecting portions connecting both ends of the support portion along the circumferential direction of the exhaust muffler and both ends of the arc portion along the circumferential direction of the catalytic converter. 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, The first feature is that the exhaust muffler is formed apart from the inner wall surface so as to allow the exhaust gas to circulate around the support stay in a range excluding a predetermined range in the circumferential direction.

In addition, the to-be-welded part of embodiment respond | corresponds to the support part of this invention.

In addition to the configuration of the first feature , the present invention has a second feature that 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 first or second feature, the support stay includes a holding portion that slidably holds the catalytic converter on the downstream side of the catalytic converter, and the holding portion The third feature is that the diameter is increased in a tapered shape toward the upstream side of the catalytic converter.

In addition to any one of the configurations of the first to third features, the present invention has a fourth feature that the predetermined circumferential range is set to be less than a half circumference of the catalytic converter.

According to a fifth aspect of the present invention, in addition to any one of the first to fourth features, the support portion of the attachment portion is supported on the inner wall surface of the exhaust muffler by welding. .

In addition to any of the configurations of the first to fifth features, 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.

Furthermore, the present invention provides a muffler suspension bracket that is fixed to the engine body so as to support the exhaust muffler, in addition to any of the configurations of the first to eighth features. It is a ninth feature that it is integrated with a fixing bracket for fixing.

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.

Also, support stay has a mounting portion for mounting the support stay to the inner wall surface of the exhaust muffler, the mounting portion, in a projection view on a plane perpendicular to the central axis of the exhaust muffler, the exhaust muffler Since it is formed to have a support part supported by the inner wall surface, an arc part covering the half circumference of the catalytic converter, and a pair of connecting parts connecting both ends of the support part and both ends of the arc part, The catalytic converter can be held while facilitating support of the support stay to the wall surface.

Furthermore, according to the second feature of the present invention, since the support stay has a shape opened in a bowl shape toward the upstream side of the catalytic converter, the rigidity of the support stay can be ensured.

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

According to the fifth aspect of the present invention, since the support portion of the mounting portion of the support stay is supported by welding on the inner wall surface of the exhaust muffler, it is easy to weld the support stay to the inner wall surface of the exhaust muffler. A catalytic converter can be retained.

  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 a projection drawing showing the plane perpendicular to the central axis C M of the exhaust muffler 35, as best shown in FIG. 3, is formed in an arc shape along the inner wall surface 38a 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 shape that covers the half circumference of the catalytic converter 36 on the opposite side of the catalytic converter 36 from the welded portion 42aa. An arc 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 provided. It is formed.

  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 (support part)
42ab ... arc portion 42ac ... connection portion 42b ... holding portion 43 ... gap 44 ... tail pipe 46 ... muffler suspension bracket 50 ... rod 51 as a vehicle component Fixed bracket CC ・ ・ ・ Catalyst converter center axis CM ・ ・ ・ Exhaust muffler center axis

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 device of the internal combustion engine connected to the catalytic converter (36),
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 slidable holding of the catalytic converter (36). The stay (42) has an attachment portion (42a) for attaching the support stay (42) to the inner wall surface (38a) of the exhaust muffler (35), and the attachment portion (42a) is the exhaust muffler. A support part (42aa) supported by the inner wall surface (38a) of the exhaust muffler (35), and the catalytic converter (36) on a projection view on a plane orthogonal to the central axis (CM) of (35). The arc portion (42ab) formed in an arc shape so as to cover the half circumference of the catalytic converter (36) on the opposite side to the support portion (42aa), and the exhaust muffler (35) A pair of connecting portions (42ac) connecting both ends of the support portion (42aa) along the direction and both ends of the arc portion (42ab) along the circumferential direction of the catalytic converter (36), The support stay (42) includes a portion where the distance between the catalytic converter (36) and the inner wall surface (38a) of the exhaust muffler (35) is the shortest in the circumferential direction of the catalytic converter (36). While the exhaust gas flow is prevented in the set circumferential range, the exhaust muffler (in order to allow the exhaust gas to flow around the support stay (42) in the range excluding the circumferential range. 35) An exhaust device for an internal combustion engine, which is formed apart from the inner wall surface (38a). The exhaust system for an internal combustion engine according to claim 1, 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 support stay (42) has a holding portion (42b) for slidably holding the catalytic converter (36) on the downstream side of the catalytic converter (36), and from the holding portion (42b) to the catalytic converter. 3. The exhaust system for an internal combustion engine according to claim 1, wherein the diameter is increased in a tapered shape toward the upstream side of (36).   The exhaust device for an internal combustion engine according to any one of claims 1 to 3, wherein the predetermined range in the circumferential direction is set to be less than a half circumference of the catalytic converter (36). The said support part (42aa) of the said attaching part (42a) is supported by the said inner wall surface (38a) of the said exhaust muffler (35) by welding, The any one of Claims 1-4 characterized by the above-mentioned. An exhaust system for an internal combustion engine as described. According to the circular arc portion (42ab) and any one of claims 1 to 5, wherein a gap (43) is formed between the outer periphery of the catalytic converter (36) of said mounting portion (42a) An exhaust system for an internal combustion engine.   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 any one of claims 1 to 8, wherein the exhaust device is integrated with (51).

Images