WO2018173630A1

WO2018173630A1 - Exhaust device for saddled vehicle

Info

Publication number: WO2018173630A1
Application number: PCT/JP2018/006819
Authority: WO
Inventors: 隆史鵜殿; 藤久保　誠; 俊博久保
Original assignee: 本田技研工業株式会社
Priority date: 2017-03-22
Filing date: 2018-02-23
Publication date: 2018-09-27

Abstract

This exhaust device (40) for a saddled vehicle (10) is provided with: a catalyst (53) for purifying the exhaust gas of an internal combustion engine (17); a catalyst containing case (48) for containing the catalyst (53); and an exhaust pipe (47) connected to the cylinder head (39) of the internal combustion engine (17). The catalyst containing case (48) has a flange (48f) extending radially outward from one end of the catalyst containing case (48). The flange (48f) is affixed by being gripped between the cylinder head (39) and the mounting front end (47e) of the exhaust pipe (47).

Description

Exhaust system for straddle-type vehicles

The present invention relates to an exhaust system for a straddle-type vehicle, and more particularly to an exhaust system for a straddle-type vehicle provided with a catalyst in an exhaust path.

As a structure of an exhaust system of a conventional straddle-type vehicle, an exhaust muffler, an exhaust pipe (joint pipe), and a catalyst device are formed as separate bodies, and a connection flange formed on the exhaust pipe and a front end of the exhaust muffler A structure is known in which a mounting flange for a catalyst device is sandwiched between walls, and the exhaust pipe, the catalyst device, and the exhaust muffler are detachably fastened via a fastening member (bolt) (for example, Patent Literature 1).

Japanese Patent Laid-Open Publication No. 2001-295641

However, as in the structure described in Patent Document 1, in the structure in which the catalyst device is accommodated in the exhaust muffler and the catalyst device is removable, the three members of the exhaust pipe, the exhaust muffler and the exhaust device are fastening members. In this case, the structure of the connection portion of each member is complicated and the number of parts is increased, which causes the problem that the assembling and removing operations become complicated.

The present invention provides an exhaust system for a straddle-type vehicle, which is easy to incorporate the catalyst into the exhaust pipe and to remove the catalyst from the exhaust pipe and has excellent maintainability.

The present invention provides the following aspects.
The first aspect is
A catalyst for purifying exhaust gas of an internal combustion engine;
A catalyst storage case for storing the catalyst;
An exhaust pipe connected to a cylinder head of the internal combustion engine;
An exhaust system for a straddle-type vehicle comprising
The catalyst storage case has a flange portion extending radially outward from one end of the catalyst storage case, and the flange portion is sandwiched between the cylinder head and the mounting tip of the exhaust pipe. It is characterized by being fixed.

In the second aspect, in addition to the configuration of the first aspect,
A bypass passage through which exhaust gas passes is provided between the outer surface of the catalyst housing case and the inner wall of the exhaust pipe,
The catalyst storage case is characterized in that a first communication hole communicating with the bypass passage is provided in an upstream space portion on the upstream side of a storage portion in which the catalyst is stored.

In the third aspect, in addition to the configuration of the first or second aspect,
A bypass passage through which exhaust gas passes is provided between the outer surface of the catalyst housing case and the inner wall of the exhaust pipe,
The flange portion is provided with a second communication hole communicating with the bypass passage.

According to a fourth aspect, in addition to the configuration of any one of the first to third aspects,
The catalyst storage case is characterized in that a spring member is provided on an outer surface of the catalyst storage case so as to elastically contact an inner wall of the exhaust pipe.

According to a fifth aspect, in addition to the configuration of the fourth aspect,
The spring member is a leaf spring, and the surface is provided along the flow direction of the exhaust gas.

In a sixth aspect, in addition to the configuration of any of the first to fifth aspects,
The exhaust pipe is provided with an exhaust pipe side tapered surface which is expanded in diameter toward the downstream side of the exhaust pipe on the outer peripheral surface of the mounting tip portion,
The cylinder head is characterized in that a head side tapered surface facing the exhaust pipe side tapered surface is provided.

According to the first aspect, the catalyst storage case has a flange portion extending radially outward from one end thereof, and the flange portion is sandwiched between the cylinder head and the mounting tip of the exhaust pipe. Since the catalyst holding case can be easily removed from the exhaust pipe by the removal operation of the exhaust pipe, the catalyst housing case can be easily incorporated into the exhaust pipe. Therefore, the catalyst can be easily exchanged, and the maintainability is improved. In addition, it is not necessary to replace the entire exhaust pipe by replacing only the catalyst housing case, and maintenance costs can be reduced.

According to the second aspect, the bypass passage is provided between the exhaust pipe and the catalyst storage case, and the catalyst storage case communicates with the bypass passage in the upstream space portion on the upstream side of the storage portion in which the catalyst is stored. Because the first communication hole is provided, pressure loss of the exhaust gas from the combustion chamber can be reduced even when the catalyst is disposed in the vicinity of the cylinder head on the upstream side of the exhaust pipe.

According to the third aspect, the bypass passage is provided between the exhaust pipe and the catalyst housing case, and the flange portion is provided with the second communication hole communicating with the bypass passage. Even when the catalyst is disposed near the cylinder head, the pressure loss of the exhaust gas from the combustion chamber can be reduced.

According to the fourth aspect, the catalyst housing case is provided on the outer surface thereof with the spring member that elastically contacts the inner wall of the exhaust pipe, so the catalyst housing case can be held in the exhaust pipe. In addition, when the catalyst housing case is incorporated, the spring member can be temporarily fixed to the exhaust pipe, and the incorporation is excellent.

According to the fifth aspect, since the spring member is a leaf spring and the surface is provided along the flow direction of the exhaust gas, it is possible to reduce the pressure loss of the exhaust gas from the combustion chamber.

According to the sixth aspect, since the head-side tapered surface of the cylinder head and the exhaust-pipe-side tapered surface of the exhaust pipe are configured to face each other, positioning becomes easy when assembling the exhaust pipe. Further, by sealing both members with a tapered surface, the gasket can be made one, and when attaching the exhaust pipe, the number of parts can be reduced and rattling of the exhaust pipe can be prevented.

FIG. 1 is a left side view of a motorcycle according to a first embodiment of the present invention. FIG. 2 is a schematic view of an essential part of an exhaust system of the motorcycle shown in FIG. 1; It is principal part sectional drawing of the attachment part to the cylinder head of the exhaust device shown in FIG. It is principal part sectional drawing of the attachment part to the cylinder head of the exhaust device in 2nd Embodiment of this invention. FIG. 5 is a partial cross-sectional view along the line AA in FIG. 4; It is principal part sectional drawing of the attachment part to the cylinder head of the exhaust device in 3rd Embodiment of this invention. It is principal part sectional drawing of the attachment part to the cylinder head of the exhaust device in 4th Embodiment of this invention.

Hereinafter, a motorcycle which is a straddle-type vehicle of each embodiment of the present invention will be described with reference to the drawings. In the following description, front, rear, left, right, top, and bottom are described according to the direction viewed from the driver, and in the drawings, the front of the vehicle is Fr, the rear is Rr, and the left is L, the right side is indicated as R, the upper side is indicated as U, and the lower side is indicated as D.

First Embodiment
First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the motorcycle 10 includes a vehicle body frame 11, a front wheel steering unit 15 that steerably supports a front wheel 13 at the front of the vehicle body frame 11, and a vehicle body frame behind the front wheel steering unit 15. 11, an internal combustion engine 17 as a drive source suspended by the internal combustion engine 17, a rear wheel suspension portion 16 pivotally supporting the rear wheel 14 on the vehicle body frame 11 behind the internal combustion engine 17, and a vehicle body behind the front wheel steering portion 15. The straddle-type vehicle is provided with a fuel tank 18 and a seat 19 attached to the front and rear of the frame 11, and a passenger sits on the seat 19.

The body frame 11 has a head pipe 21 for steering the front wheel steering portion 15 in a steerable manner, and a downward bent portion 22 bent downward from the head pipe 21 after being inclined slightly rearward and downward in the vehicle. While the main frame 23 extends downward to support the internal combustion engine 17 and the fuel tank 18, the down frame 24 also extending obliquely downward from the head pipe 21 in the vehicle width direction center, and the lower bending portion of the main frame 23 A seat rail 26 extending to the rear of the vehicle to support the seat 19 while forming an upper bending portion 27 extending rearward from the vehicle 22 and bending upward in the middle, and between the upper bending portion 27 of the seat rail 26 and the main frame 23 And the support frame 28 passed to are the main components.

The front wheel steering unit 15 includes a steering handle 31, a front fork 32 extending downward from the steering handle 31 with a predetermined caster angle, and a front wheel 13 rotatably supported at the lower end of the front fork 32. It is the main component. The rear wheel suspension 16 includes a swing arm 33 extending from the lower portion of the main frame 23 to the rear of the vehicle, a rear wheel 14 rotatably supported at the rear end of the swing arm 33, and between the swing arm 33 and the seat rail 26. The rear cushion 34 to be delivered is the main component.

The internal combustion engine 17 mainly includes a crankcase 37, a cylinder block 38 extending upward slightly from the upper surface of the crankcase 37 and extending upward, and a cylinder head 39 disposed above the cylinder block 38. As an element, an intake device 12 is connected to an intake port 42 (see FIG. 2) formed in a rear wall 39b of the cylinder head 39, and an exhaust port 41 (see FIG. 2) formed in a front wall 39a of the cylinder head 39. The exhaust system 40 is connected. In the internal combustion engine 17, the front of the crankcase 37 is attached to a front hanger 43 provided at the lower part of the down frame 24, and the rear of the crankcase 37 is attached to a rear hanger 44 provided at the lower part of the main frame 23. It is suspended on the vehicle body frame 11. A guard frame 45 that guards the internal combustion engine 17 is attached to the down frame 24.

Next, the exhaust system 40 will be described in detail.
The exhaust system 40 mounted on the motorcycle 10 extends forward from the front wall 39a of the cylinder head 39 as shown in FIGS. 1 and 2 and then bends downward and obliquely diagonally along the crankcase 37. And an exhaust pipe 47 extending backward along the lower end of the crankcase 37, a catalyst 53 for purifying the exhaust gas of the internal combustion engine 17, and an attachment position of the exhaust pipe 47 to the cylinder head 39, A catalyst storage case 48 for storing the catalyst 53 and a muffler 49 extending rearward from the rear end of the exhaust pipe 47 along the swing arm 33 are provided. At the rear of the exhaust pipe 47, a stay member 51 attached to the rear hanger 44 on the vehicle side is provided.

An exhaust pipe 47 is connected to an exhaust port 41 of a cylinder head 39 of the internal combustion engine 17. The exhaust pipe 47 is fixed by screwing the mounting flange 58 provided at the tip to the front wall 39 a of the cylinder head 39 by the fastening member 59, whereby the exhaust gas of the internal combustion engine 17 is exhausted through the exhaust port 41. Through the exhaust pipe 55 formed by the exhaust pipe 47 and the silencer 49 to the outside.

As shown in FIG. 3, the exhaust pipe 47 is provided with a mounting joint 47 a attached to the exhaust port 41, and the mounting joint 47 a is fitted into the exhaust port side recess 41 e of the exhaust port 41. The attachment joint 47a includes a large diameter joint 47ar to which the attachment flange 58 is attached and a small diameter joint 47af having a smaller diameter than the large diameter joint 47ar provided on the opposite side of the attachment flange 58 across the large diameter joint 47ar. Configured The large diameter coupling portion 47ar is accommodated in the large diameter recess 41er of the exhaust port side recess 41e, and the small diameter coupling portion 47af is loosely fitted in the small diameter recess 41ef of the exhaust port side recess 41e.

Next, the mounting structure of the catalyst housing case 48 will be described with reference to FIG.
The catalyst housing case 48 is provided with a flange portion 48 f extending radially outward from the tip end of the cylindrical catalyst housing case 48. Then, the flange portion 48 f is fixed in the exhaust pipe 47 by being sandwiched between the bottom wall 41 aw of the exhaust port side concave portion 41 e and the attachment tip portion 47 e of the attachment joint portion 47 a of the exhaust pipe 47.

The external dimensions of the catalyst housing case 48 are, for example, substantially the same dimensions as the inner wall surface of the exhaust pipe 47 so as to be loosely fitted to the inner wall surface of the exhaust pipe 47. Thus, the catalyst storage case 48 is held in the exhaust pipe 47. Further, two gaskets 41g are disposed on the front and rear of the flange portion 48f between the bottom wall 41aw of the exhaust port side recess 41e and the attachment tip portion 47e of the attachment joint portion 47a of the exhaust pipe 47 to ensure hermeticity. It is done.

As described above, in the present embodiment, the catalyst housing case 48 has a flange portion 48 f extending radially outward from one end thereof, and the flange portion 48 f is a mounting tip of the cylinder head 39 and the exhaust pipe 47. Since the catalyst housing case 48 can be easily removed from the exhaust pipe 47 by the removal operation of the exhaust pipe 47 because it is fixed by being sandwiched between the portion 47 e and the catalyst housing case 48 can be easily made to the exhaust pipe 47 Can be incorporated into Therefore, the catalyst 53 can be easily replaced, and the maintainability is improved. Moreover, it is not necessary to replace | exchange the exhaust pipe 47 whole by replacement | exchange of only the catalyst accommodation case 48, and can suppress a maintenance cost.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG. 4 and FIG. 4 is a cross-sectional view of an essential part of a mounting portion of the exhaust system of the second embodiment to a cylinder head, and FIG. 5 is a cross-sectional view taken along the line AA in FIG. Further, in FIG. 4 and FIG. 5, the same components as in the first embodiment will be assigned the same reference numerals and explanation thereof will be omitted.

The exhaust device 40 of the present embodiment differs from the first embodiment in that, as shown in FIG. 4, exhaust gas is generated between the outer surface 48 us of the catalyst housing case 48 and the inner wall 47 is of the exhaust pipe 47. A bypass passage 55b is formed to pass through. In addition, a space 68 (hereinafter referred to as an upstream space 68) is provided in the catalyst housing case 48 on the upstream side of the housing 48b in which the catalyst 53 is housed, and the upstream space 68 is bypassed. A plurality of first communication holes 48bh communicating with the passage 55b are provided. Therefore, the exhaust gas from the exhaust port 41 flows into the inside of the catalyst 53 of the catalyst housing case 48 and also flows into the bypass passage 55b through the first communication hole 48bh.

Further, on the outer surface 48us of the catalyst housing case 48, a spring member 48m that elastically contacts the inner surface wall 47is of the exhaust pipe 47 is provided.

The spring member 48m is a so-called leaf spring, is fixed to the outer surface 48us of the catalyst housing case 48, extends toward the inner wall 47is of the exhaust pipe 47 and is appropriately bent in the circumferential direction. It has a Z-shape or a curved substantially S-shape.

The spring member 48m is provided such that the surface 48ms of the spring member 48m is along the flow direction of the exhaust gas. In addition, as shown in FIG. 5, the spring members 48m are arranged in such a manner that the pair of spring members 48m closely disposed so that the tip end portions 48me face each other at three places at equal intervals in the circumferential direction of the outer surface 48us Two rows are provided upstream and downstream (see FIG. 4). The catalyst housing case 48 is held in the exhaust pipe 47 by the resilient contact of the front end portion 48me of the spring member 48m with the inner wall 47is of the exhaust pipe 47.

As described above, in the present embodiment, the bypass passage 55b is provided between the exhaust pipe 47 and the catalyst housing case 48, and the catalyst housing case 48 has a space on the upstream side of the housing portion 48b in which the catalyst 53 is housed. Since the first communication hole 48bh communicating with the bypass passage 55b is provided at 68, pressure loss of exhaust gas from the combustion chamber can be reduced even when the catalyst 53 is disposed in the vicinity of the cylinder head 39 upstream of the exhaust pipe 47. Can.

Further, the catalyst housing case 48 is provided with the spring member 48m resiliently in contact with the inner surface wall 47is of the exhaust pipe 47 on the outer surface 48us thereof, so that the catalyst housing case 48 can be held in the exhaust pipe 47. In addition, the catalyst storage case 48 can be temporarily fixed to the exhaust pipe 47 when the catalyst storage case 48 is assembled by the spring member 48m, and the incorporation property is also excellent.

Further, since the spring member 48m is a leaf spring and the surface 48ms is provided along the flow direction of the exhaust gas, the pressure loss of the exhaust gas from the combustion chamber can be reduced.

Third Embodiment
Subsequently, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of an essential part of the mounting portion of the exhaust system of the third embodiment to the cylinder head. In FIG. 6, the same components as in the second embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

The exhaust device 40 of the present embodiment is the same as the second embodiment in that a bypass passage 55b through which exhaust gas passes is formed between the outer surface 48us of the catalyst housing case 48 and the inner surface wall 47is of the exhaust pipe 47. However, the difference is that the flange portion 48f is provided with a second communication hole 48fh communicating with the bypass passage 55b.

In the present embodiment, the inner diameter of the exhaust port 41 of the cylinder head 39 is enlarged until it overlaps with the flange portion 48f in the radial direction, and the exhaust gas can be obtained by providing the second communication hole 48fh in the flange portion 48f. Flows into the bypass passage 55b via the second communication hole 48fh.

As described above, in the present embodiment, the bypass passage 55b is provided between the exhaust pipe 47 and the catalyst housing case 48, and the flange portion 48f is provided with the second communication hole 48fh communicating with the bypass passage 55b. Even when the catalyst 53 is disposed in the vicinity of the cylinder head 39 upstream of the exhaust pipe 47, the pressure loss of the exhaust gas from the combustion chamber can be reduced.

Fourth Embodiment
Subsequently, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view of an essential part of the mounting portion of the exhaust system of the fourth embodiment to the cylinder head. In FIG. 7, the same components as in the first embodiment are given the same reference numerals, and the description thereof is omitted.

The exhaust device 40 of this embodiment is configured such that the small diameter coupling portion 47af of the attachment coupling portion 47a is gradually reduced in diameter from the large diameter coupling portion 47ar, so that the outer peripheral surface of the small diameter coupling portion 47af has a tapered surface 47t. , And the small diameter recess 41ef of the cylinder head 39 is also gradually enlarged from the bottom wall 41aw, so that the inner peripheral surface of the small diameter recess 41ef is a tapered surface. This embodiment is different from the first embodiment in that 39t (hereinafter referred to as a head-side tapered surface 39t) is formed.

A gasket 41g is provided between the exhaust pipe side tapered surface 47t and the head side tapered surface 39t.

As described above, in the present embodiment, since the head-side tapered surface 39t of the cylinder head 39 and the exhaust-pipe-side tapered surface 47t of the exhaust pipe 47 face each other, positioning is easy when assembling the exhaust pipe 47. become. Further, by arranging the gasket 41g between the exhaust pipe side tapered surface 47t and the head side tapered surface 39t, the gasket 41g can be made one, and when attaching the exhaust pipe 47, the number of parts can be reduced and the exhaust can be reduced. The rattling of the tube 47 can be prevented.

The first to fourth embodiments of the present invention have been described above, but the present invention is not limited to this and can be modified as appropriate.
For example, although a motorcycle has been described in the above embodiment, the present invention may be another straddle-type vehicle such as a buggy.

This application is based on Japanese Patent Application (Japanese Patent Application No. 2017-056330) filed on March 22, 2017, the contents of which are incorporated herein by reference.

10 Motorcycles (saddle-type vehicles)
17 internal combustion engine 39 cylinder head 39t head side tapered surface 40 exhaust device 47 exhaust pipe 47e mounting tip 47is inner surface wall 47t exhaust pipe side tapered surface 48 catalyst housing case 48b housing portion 48bh first communication hole 48f flange portion 48fh second communication hole 48 m spring member 48 ms surface 48 us outer surface 53 catalyst 55 b bypass passage 68 upstream space portion

Claims

A catalyst (53) for purifying the exhaust gas of the internal combustion engine (17);
A catalyst storage case (48) for storing the catalyst (53);
And an exhaust pipe (47) connected to a cylinder head (39) of the internal combustion engine (17), and an exhaust system (40) of a straddle-type vehicle (10),
The catalyst storage case (48) has a flange (48f) extending radially outward from one end of the catalyst storage case (48), and the flange (48f) is the cylinder head (39). And a mounting tip portion (47e) of the exhaust pipe (47).
A bypass passage (55b) through which exhaust gas passes is provided between the outer surface (48us) of the catalyst housing case (48) and the inner wall (47is) of the exhaust pipe (47),
A first communication hole communicating with the bypass passage (55b) in the upstream space portion (68) on the upstream side of the accommodation portion (48b) in which the catalyst (53) is accommodated in the catalyst accommodation case (48) The exhaust system (40) of a straddle-type vehicle according to claim 1, characterized in that (48bh) is provided.
A bypass passage (55b) through which exhaust gas passes is provided between the outer surface (48us) of the catalyst housing case (48) and the inner wall (47is) of the exhaust pipe (47),
The exhaust gas of a saddle-ride type vehicle according to claim 1 or 2, wherein the flange portion (48f) is provided with a second communication hole (48fh) communicating with the bypass passage (55b). Device (40).
The catalyst storage case (48) is provided with a spring member (48m) that elastically contacts the inner wall (47is) of the exhaust pipe (47) on the outer surface (48us) of the catalyst storage case (48). The exhaust system (40) of a straddle-type vehicle according to any one of the preceding claims, characterized in that
5. The exhaust system of a saddle-ride type vehicle according to claim 4, wherein said spring member (48 m) is a leaf spring, and a surface (48 ms) is provided along the flow direction of the exhaust gas. 40).
The exhaust pipe (47) is provided with an exhaust pipe side tapered surface (47t) whose diameter increases toward the downstream side of the exhaust pipe (47) on the outer peripheral surface of the mounting tip portion (47e).
The cylinder head (39) is provided with a head-side tapered surface (39t) facing the exhaust pipe-side tapered surface (47t) according to any one of claims 1 to 5, An exhaust system (40) for a straddle-type vehicle as described.