JP2011256785A - Exhaust device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust device capable of contributing to weight reduction and higher sealing property and improving durability while reducing the number of equipment and working man-hour.SOLUTION: The exhaust device 23 includes an exhaust pipe, the upstream end of which is connected to an exhaust port, a manifold 35 connected to the downstream end of the exhaust pipe, a tubular catalyst device 37 connected to the downstream end of the manifold 35, a connecting pipe 38 connected to the downstream end of the catalyst device 37. The catalyst device 37 includes: a catalyst outer cylinder 49 made of metal, which holds a catalyst carrier 36; and a catalyst casing 48 located outside the catalyst outer cylinder 49 and caulking and holding the catalyst outer cylinder 49. The exhaust pipe, manifold 35, catalyst casing 48 and connecting pipe 38 are formed of the same metal, which is different from the metal of the catalyst outer cylinder 49, and each pipe body 35, 48, 38 formed of the same metal is connected to others by welding.

Description

  The present invention relates to an exhaust device that is mounted on a vehicle such as an automobile, a motorcycle, or a tricycle, and exhausts air burned by an engine.

  2. Description of the Related Art Conventionally, vehicles such as automobiles and motorcycles are equipped with an exhaust device that guides air burned by an engine toward the rear of the vehicle body and exhausts the air in a silenced and cleaned state. In addition, such an exhaust device includes an exhaust pipe that extends toward the rear of the vehicle body while connecting a plurality of pipes, taking into consideration the layout with peripheral devices, including pipes such as catalyst devices and mufflers. Structures are also well known.

  When this type of exhaust system is provided in a motorcycle equipped with a multi-cylinder engine, if a plurality of pipes extending from each engine port are extended as they are to the rear of the vehicle body, this is accompanied by a phase difference between the cylinders. The engine output cannot be improved because the pulsation effect of the exhaust gas cannot be used, and it may cause an increase in the size and weight of the vehicle body. Therefore, consideration must be given to the arrangement with other peripheral devices and travel characteristics (bank angle, etc.). In many cases, the catalyst devices are arranged and connected after being assembled in the collecting pipe, and a muffler is arranged downstream thereof. Since this catalyst device becomes very hot due to heat of reaction such as oxidation / reduction, it is common to use stainless steel with high heat resistance and low thermal deformation for the catalyst case that supports the catalyst carrier. .

  On the other hand, in the exhaust pipe used in the exhaust device, a high-temperature exhaust gas circulates inside, and water vapor condenses after the engine is stopped. In addition, since the exhaust pipe is heavy, an exhaust pipe made of titanium or a titanium alloy is used for the purpose of reducing the weight particularly in a road sports model in which sports running performance (acceleration, etc.) is emphasized. For this reason, in the exhaust system parts of the road sport model, different pipes may be used for each pipe body.

  In such a case, since it is generally difficult to weld between metal parts of different materials, a catalyst pipe (for example, stainless steel) made of a different metal and pipes ( For example, when connecting to titanium), it is preferable to connect with a fitting joint such as tightening with a tubular connection belt or forming flanges at connection ends and tightening each flange with bolts, nuts, etc. (For example, refer to Patent Document 1).

JP 2007-05571 A

  However, in the exhaust device described above, since a fitting joint such as a belt, a bolt, and a nut is used for connecting the tubular body between the catalyst device and the upstream and downstream sides thereof, it is necessary to provide a hermetic seal on the connection portion. In addition, there has been a problem that the number of work steps including the securing of assembly accuracy increases.

  Further, the above-described fitting joint not only increases the number of parts, but also has a problem that it cannot contribute to weight reduction as a result of the relatively heavy part weight.

  Moreover, if different metals are used, the coefficient of thermal expansion of each tube will be different, so it is necessary to adopt a configuration that absorbs deformation differences due to thermal expansion. Has increased further.

  Therefore, the present invention has been made in view of the above problems, and while using a tube body made of a dissimilar metal, the number of parts and the number of work steps can be reduced, and the weight reduction and sealing can be achieved. It is an object of the present invention to provide an exhaust device that can contribute to improvement of performance and can improve durability.

  The present invention relates to an exhaust pipe having an upstream end connected to an exhaust port of an engine, an upstream connection pipe connected to the downstream end of the exhaust pipe, and a tubular body connected to the downstream end of the upstream connection pipe In the exhaust device comprising the catalyst device and a downstream connection pipe connected to the downstream end of the catalyst device, the catalyst device includes a metal catalyst outer cylinder holding a catalyst carrier, and the catalyst outer cylinder. A catalyst case that caulks and holds the catalyst outer cylinder, and the exhaust pipe, the upstream connection pipe, the catalyst case, and the downstream connection pipe are made of the same metal and the catalyst outer cylinder. Is composed of different metals, and pipes composed of these same metals are connected by welding.

  In this case, at least one end of the catalyst outer cylinder extends in the axial direction from the catalyst carrier, and the end of the catalyst case is folded back radially inward to extend the extended end of the catalyst outer cylinder. It is preferable to crimp the part.

  Further, it is preferable that the outer peripheral surface of the folded caulking holding portion of the catalyst case and the upstream connection pipe are welded and joined.

  Further, it is preferable that a throttle-like stepped portion is formed at the upstream end of the downstream side connecting pipe, and the downstream end of the catalyst outer cylinder is abutted against the inner surface of the stepped portion to prevent it from coming off.

  Furthermore, it is preferable that an air layer is formed between the catalyst case and the catalyst casing at an intermediate portion of the catalyst case.

  According to the exhaust device of the present invention, the number of parts and the number of work steps can be reduced while using a pipe body made of a different metal, which can contribute to weight reduction and improved sealing performance. Moreover, durability can be improved.

1 is a left side view showing a motorcycle equipped with an exhaust device according to an embodiment of the present invention. 1 is a left side view showing a housing of a motorcycle equipped with an exhaust device according to an embodiment of the present invention. 1 is a plan view showing a schematic overall configuration of an exhaust device according to an embodiment of the present invention. It is a front view of the principal part which shows the relationship with the peripheral device of the exhaust apparatus of one Embodiment of this invention. It is a right view of the principal part which shows the relationship between the exhaust apparatus of one Embodiment of this invention, and peripheral equipment. It is a rear view of the principal part which shows the relationship with the peripheral device of the exhaust apparatus of one Embodiment of this invention. It is a left view which expands and shows the principal part of the exhaust apparatus of one Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the exhaust apparatus of one Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the pipe body connection part in the exhaust apparatus of one Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the pipe body connection part in the modification of the exhaust apparatus of one Embodiment of this invention.

  Next, an exhaust system according to an embodiment of the present invention is applied to an exhaust system mounted on a motorcycle and will be described with reference to the drawings. The following embodiment is a preferred specific example of the exhaust device of the present invention, and may have various technically preferable limitations. However, the technical scope of the present invention is not limited to the present invention. As long as there is no description which limits, it is not limited to these aspects. In addition, the constituent elements in the embodiments shown below can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the contents of the invention described in the claims are not limited by the description of the embodiment described below including the type of the exhaust device.

  FIG. 1 is a left side view showing a motorcycle equipped with an exhaust device according to an embodiment of the present invention. FIG. 2 is a left side view showing a housing of the motorcycle equipped with an exhaust device according to an embodiment of the present invention. 3 is a plan view showing a schematic overall configuration of an exhaust apparatus according to an embodiment of the present invention, FIG. 4 is a front view of a main part showing the relationship between the exhaust apparatus according to an embodiment of the present invention and peripheral devices, and FIG. The right view of the principal part which shows the relationship with the peripheral equipment of the exhaust apparatus of one Embodiment of this invention, FIG. 6 is a rear view of the principal part which shows the relation with the peripheral equipment of the exhaust apparatus of one embodiment of this invention, FIG. 7 is a left side view showing an enlarged main part of an exhaust device according to an embodiment of the present invention, FIG. 8 is a sectional view showing an enlarged main part of the exhaust device according to an embodiment of the present invention, and FIG. Sectional drawing which expands and shows the principal part of the pipe | tube connection part in the exhaust apparatus of one Embodiment of this invention, FIG. 10 is one Embodiment of this invention. Is a sectional view showing an enlarged main portion of the tube connecting portion in a modification of the exhaust device.

  1 and 2, a motorcycle 10 according to an embodiment of the present invention includes, as a casing, a vehicle body rear left and right (only the left side of the vehicle is shown in the figure) and a vehicle rear of a head pipe 11 disposed at the center of the vehicle body. A pair of left and right main frames 12 extending so as to branch up and down; a pair of left and right body frames 13 extending in a bent state from the upper left and right ends of the main frame 12 toward the lower rear of the vehicle; A reinforcement frame 14 connected across the middle part of the body frame 13 from the left and right lower ends of the main frame 12, and a seat frame 15 extending upward from the middle part of the body frame 13 to the rear of the vehicle body. Yes.

  Further, the motorcycle 10 includes a front fork 17 that is connected to the head pipe 11 and pivotally supports the front wheel 16, and a swing arm 19 that is rotatably connected to the lower end of the body frame 13 via a pivot shaft 18. The rear wheel 20 rotatably supported by the swing arm 19, the seat 21 fixed to the seat frame 15, and straddling the main frame 12, the body frame 13, and the reinforcement frame 14 adjacent to the front of the vehicle body of the seat 21. A mounted multi-cylinder engine 22, an exhaust device 23 for exhausting the multi-cylinder engine 22, a fuel tank 24 disposed in front of the seat 21, and a front cowling fixed to the body frame 13 and disposed in front of the vehicle body 25, a side cowling 26 connected to the front cowling and covering the multi-cylinder engine 22 and an under cover. Is provided with a ring 27, a.

  The vertical swing of the swing arm 19 is buffered by the rear wheel suspension device 28 to restore the position. After that, the wheel suspension device 28 is provided at a cushion shaft 29 laid between the left and right body frames 13, a link rod 30 having one end rotatably supported by the cushion shaft 29, and one end of the link rod 30. A substantially triangular link plate 31 connected to the swing arm 19 and a rear shock absorber 32 supported by the link plate 31 are provided. The link plate 31 has a link rod 30, a swing arm 19, and a rear shock absorber 32 connected to each vertex of the link plate 31, and the link plate 31 supports the passenger load and road load during traveling by supporting the link plate 31 at three points. Even if the swing arm 19 swings up and down, the rear wheel 20 position (height between the occupant and the road surface) is restored by buffering.

  As well shown in FIGS. 3 to 6, the exhaust device 23 includes four exhaust pipes 33 connected at one end to the multi-cylinder engine 22 and two exhaust pipes at the downstream end of the exhaust pipe 33 in the exhaust direction. Two front collecting pipes 34 connected together, a rear collecting pipe 35 joined together at the downstream end of the two front collecting pipes 34 in the exhaust direction, and an exhaust direction of the rear collecting pipe 35 A tubular catalyst device 37 connected to the downstream end and including the catalyst carrier 36, a connection pipe 38 connected to the downstream end of the catalyst device 37 in the exhaust direction, and a downstream end of the connection pipe 38 in the exhaust direction are located on the right side of the vehicle body. And an exhaust muffler 39 connected in this manner. That is, in the exhaust device 23 according to the present embodiment, in the road sports model motorcycle 10 equipped with the four-cylinder multi-cylinder engine 22, four exhaust pipes 33, two front collecting pipes 34, one rear part are provided. A 4-2-1-1 configuration including a collecting pipe 35, a catalyst device 37, a connecting pipe 38, and a single exhaust muffler 39 is employed. It should be noted that the downstream side of the connection pipe 38 is bifurcated, and two exhaust mufflers 39 are used (4-2-1-1-2 configuration). The exhaust pipe 33, the front collecting pipe 34, the rear collecting pipe 35, and the connecting pipe 38 are all made of lightweight titanium (including a titanium alloy) that is difficult to be thermally deformed and hardly rusted.

  The rear collecting pipe 35 arranged on the upstream side of the catalyst device 37 is supported by the lower end of the body frame 13 via the bracket 40. Further, the rear collecting pipe 35 is provided with an exhaust gas sensor 41 (for example, an O 2 sensor) that detects an oxygen concentration in the exhaust through a nut (not shown) or the like. Further, on the side of the rear collecting pipe 35 (on the right side of the vehicle body), as shown in FIG. 5, the multi-cylinder engine 22 is secured by securing a space when the four exhaust pipes 33 are joined to one rear collecting pipe 35. An oil pan 42 for storing oil is disposed.

  At this time, the capacity of the oil pan 42 directly affects the total amount of oil in the multi-cylinder engine 22 used in the multi-cylinder engine 22. The oil pan 42 is often employed. The oil pan 42 also serves to cool the oil of the multi-cylinder engine 22 with traveling wind, and also serves as a precipitation type oil filter. The oil stored in the oil pan 42 is sucked up by an oil pump (not shown) equipped with an oil strainer (not shown), passes through a filter paper type oil filter (not shown), and goes to each part of the multi-cylinder engine 22. Over. In this case, the oil pan 42 is offset to the right side of the vehicle body in order to minimize the damage caused by the collision of the obstacle, and in this embodiment, a pipe body (rear collecting pipe 35) extending from the multi-cylinder engine 22 is used. ) Is disposed on the opposite side (left side) of the oil pan 42.

  In addition, an exhaust control valve 43 that changes the exhaust mode according to the operating state of the multi-cylinder engine 22 is disposed in the connecting pipe 38 that is disposed on the downstream side of the catalyst device 37, and responds to changes in the operating state. The desired output performance is optimized. As shown in FIG. 6, the exhaust control valve 43 is provided with a bearing 44 on the bottom surface side of the connection pipe 38, and adjusts the opening degree of a butterfly valve (not shown) disposed inside the pipe body. For example, the exhaust passage area (inner diameter) is throttled when high torque is required at the initial stage (starting) or the like, and the exhaust passage area is fully opened during high-speed traveling.

  As shown in FIGS. 4 and 5, a right footrest 46 and a brake pedal 47 are arranged above the space between the exhaust gas sensor 41 and the exhaust control valve 43 via a frame bracket 45 connected to the body frame 13. Therefore, the exhaust gas sensor 41 and the exhaust control valve 43 are arranged so as not to interfere as much as possible for the driver's step operation.

  As shown in FIG. 7, the catalyst device 37 is connected by an inlay connection method that is fitted inside each of the downstream end of the titanium rear collecting pipe 35 and the upstream end of the titanium connecting pipe 38. Further, as shown in FIG. 8, the catalyst device 37 includes a titanium catalyst case 48 positioned on the surface, and a stainless steel catalyst outer cylinder that is disposed inside the catalyst case 48 and has high heat resistance and low thermal deformation. 49 and a catalyst carrier 36 that is held by the catalyst outer cylinder 49 and made of a honeycomb-shaped metal catalyst.

  The downstream end of the rear collecting pipe 35 has a larger diameter than the inner diameter immediately before the upstream, and the outer peripheral surface of the upstream end of the catalyst case 48 is fitted into the inner peripheral surface of the large-diameter downstream end. Joined by welding. At this time, since the rear collecting pipe 35 and the catalyst case 48 are made of the same metal (titanium), the weldability is good. The upstream end of the connecting pipe 38 has a larger diameter than the inner diameter immediately after the downstream side. The outer peripheral surface of the downstream end of the catalyst case 48 is inserted into the inner peripheral surface of the upstream end of the large diameter. Joined by circumferential welding. At this time, since the connecting pipe 38 and the catalyst case 48 are made of the same metal (titanium), weldability is good.

  The upstream end of the catalyst outer cylinder 49 is caulked by being clamped by a folded portion 48 a that is the inner end of the catalyst case 48 folded back inward in the radial direction. By holding the crimp, the deformation due to the thermal expansion of the catalyst outer cylinder 49 does not directly affect the welded portion between the rear collecting pipe 35 and the catalyst case 48. Therefore, it is based on the difference in the thermal expansion coefficient between different metals. It is possible to suppress stress concentration on the welded portion due to the deformation, and the durability of the welded portion is further improved.

  Further, the large diameter portion and the small diameter portion at the upstream end of the connection pipe 38 are changed in diameter by a step portion 38a formed by narrowing or the like, and the downstream end of the catalyst outer cylinder 49 is in contact with the step portion 38a. Thus, the catalyst outer cylinder 49 can be prevented from slipping toward the connecting pipe 38 due to the load accompanying the inflow / outflow of the exhaust gas.

  In addition, although the catalyst case 48 is caulking and holding the catalyst outer cylinder 49 at the upstream end thereof, there is a possibility that the caulking portion may be loosened due to an external impact during long-term use. As a result, even if the catalyst outer cylinder 49 is about to be detached from the caulking portion, the catalyst outer cylinder 49 is not detached from the catalyst case 48 because the stepped portion 38a provided in the connecting pipe 38 is surely prevented from coming off.

  Further, since the catalyst outer cylinder 49 made of stainless steel is not directly welded to the connecting pipe 38 made of titanium, the heat of the catalyst carrier 36 is not easily transmitted to the welded portion, and the durability of the welded portion is improved. Similarly, since heat at the time of welding does not easily reach the catalyst carrier 36, it is possible to eliminate the heat damage on the catalyst carrier 36.

  In addition, the downstream end of the catalyst outer cylinder 49 is held so that the inner peripheral surface of the downstream end of the catalyst case 48 is in close contact with the outer peripheral surface of the catalyst outer cylinder 49. Since the end does not employ a joining structure such as welding, the above-described problems such as welding of dissimilar metals do not occur.

  Further, as shown in FIG. 9, the thickness near the downstream end of the rear collecting pipe 35 and the vicinity of the upstream end of the catalyst device 37 is determined by the thickness of the catalyst case 48 being folded (the thickness of the sandwich structure sandwiching the catalyst outer cylinder 49). Then, by expanding the large diameter portion of the rear collecting pipe 35, the occurrence of turbulent exhaust gas can be suppressed, and the exhaust gas can efficiently flow from the rear collecting pipe 35 into the catalyst carrier 36. Note that it is desirable to adopt the same diameter structure also in the stepped portion 38a.

  On the other hand, an air layer 50 is formed between the catalyst case 48 and the catalyst outer cylinder 49 by bulging outward in the radial direction at an intermediate portion of the catalyst case 48. Thereby, the heat received by the catalyst outer cylinder 49 is not easily transmitted to the catalyst case 48. Further, since the air layer 50 becomes a heat insulating layer, it is possible to prevent the period from the time when the catalyst carrier 36 is cooled by the traveling air and reaching the activation temperature from being prolonged. The air layer 50 can be filled with a heat insulating material such as glass wool or a sound insulating material.

  In the above configuration, the exhaust gas discharged from the multi-cylinder engine 22 passes through the four exhaust pipes 33, the two front collecting pipes 34, and the one rear collecting pipe 35, and then the catalyst carrier of the catalyst device 37. After being primarily purified by 36, the exhaust gas flows to the exhaust muffler 39 via the rear exhaust pipe 33, and is secondarily purified by the catalyst carrier 51 (see FIG. 3) provided in the exhaust muffler 39 (expansion chamber) to expand and silence. And then discharged to the outside.

(Modification)
FIG. 10 shows a modification of the exhaust device 23 of the present invention. In the above embodiment, the upstream end of the catalyst case 48 is folded and the catalyst outer cylinder 49 is caulked and held by the folded part 48a. However, in this modification, the folded part 59a by folding is formed in the catalyst outer cylinder 59. Is.

  That is, the upstream end of the catalyst outer cylinder 59 is bent outward in the radial direction, and the catalyst case 58 is caulked and held by the catalyst outer cylinder 59, and the exhaust gas at the connection portion between the rear collecting pipe 55 and the catalyst device 57 is retained. A turbulent flow can be further suppressed, and a decrease in output can be suppressed.

  The structure for holding the catalyst outer cylinders 49 and 59 may be any of the above-described structures. However, the structure in which the catalyst outer cylinder 49 is crimped and held by folding the upstream end of the catalyst case 48 is used for the catalyst outer cylinder 49. Since it is not necessary to perform the bending process, there is little possibility that the catalyst carrier 36 is deformed or damaged during the bending process.

  As described above, in the exhaust device 23 of the present invention, although the stainless steel is used for holding the catalyst carrier 36, the rear collecting pipe 35 and the connecting pipe 38 adjacent to the catalyst device 37 upstream and downstream. By connecting each connection with a welded joint of the same metal, connection parts such as belts and bolts and nuts that are heavier than pipe connection structures of dissimilar metals are no longer necessary, contributing to weight reduction. Further, it can contribute to improvement of sealing performance and durability.

  In the embodiment of the present invention described above, the present invention is applied to the motorcycle 10 on which the multi-cylinder engine 22 is mounted, and the upstream connecting pipe of the present invention is configured by the front collecting pipe 34 and the rear collecting pipe 35. The case where the downstream side connecting pipe of the present invention is configured by the connecting pipe 38 is described as an example, but the present invention is not limited to this case. That is, the present invention relates to one exhaust pipe, an upstream connection pipe, and a catalyst device that are bent and connected toward the downstream side in a predetermined layout from one or a plurality of exhaust ports formed in one cylinder. Also applied to motorcycles and tricycles equipped with engines other than the multi-cylinder engine 22, such as motorcycles and tricycles equipped with a single-cylinder engine having a 1-1-1-1 configuration of downstream connection pipe and exhaust muffler Is possible.

22 ... Multi-cylinder engine 23 ... Exhaust device 33 ... Exhaust pipe 34 ... Front collecting pipe (upstream connection pipe)
35 ... Rear collecting pipe (upstream connecting pipe)
36 ... Catalyst carrier 37 ... Catalyst device 38 ... Connecting pipe (downstream connecting pipe)
38a ... Step part 39 ... Exhaust muffler 48 ... Catalyst case 48a ... Folding part 49 ... Catalyst outer cylinder 50 ... Air layer 55 ... Rear collecting pipe 57 ... Catalyst device 58 ... Catalyst case 59 ... Catalyst outer cylinder 59a ... Folding part

Claims (5)

An exhaust pipe having an upstream end connected to an exhaust port of the engine, an upstream connection pipe connected to the downstream end of the exhaust pipe, and a tubular catalyst device connected to the downstream end of the upstream connection pipe An exhaust device comprising a downstream connecting pipe connected to the downstream end of the catalyst device,
The catalyst device includes a metal catalyst outer cylinder that holds a catalyst carrier, and a catalyst case that is positioned outside the catalyst outer cylinder and caulks and holds the catalyst outer cylinder.
The exhaust pipe, the upstream connection pipe, the catalyst case, and the downstream connection pipe are made of the same metal and different from the catalyst outer cylinder, and each pipe body made of the same metal is welded. An exhaust system characterized by being connected.   At least one end of the catalyst outer cylinder extends in the axial direction from the catalyst carrier, and the end of the catalyst case is folded back inward in the radial direction so that the extended end of the catalyst outer cylinder is caulked. The exhaust device according to claim 1, wherein the exhaust device is held.   The exhaust device according to claim 2, wherein an outer peripheral surface of the caulking holding portion of the catalyst case that is folded back and the upstream connection pipe are welded.   The throttle-shaped stepped portion is formed at the upstream end of the downstream connecting pipe, and the downstream end of the catalyst outer cylinder is abutted against the inner surface of the stepped portion to prevent the stepped portion from coming off. The exhaust device according to any one of 3. The exhaust device according to any one of claims 1 to 4, wherein an air layer is formed between the catalyst case and the catalyst casing at an intermediate portion of the catalyst case.

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