JP2006207571A - Exhaust device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust device for a vehicle capable of promoting catalyst activation in a cold state without enlarging a muffler connected to an exhaust pipe. <P>SOLUTION: In the exhaust device for the vehicle, the muffler 25 is connected to the exhaust pipe 23 extending from an engine 6, and a plurality of catalysts are provided. A bent part 31 having an upstream side catalyst converter 33, a downstream side catalyst converter 35, and a bent pipe 37 connecting the respective catalyst converters 33 and 35 in series is formed in a part of the exhaust pipe 23 positioned near the engine 6 and extending to the muffler 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust device for a vehicle including a catalytic converter.

In general, an exhaust device for a vehicle in which a catalyst is disposed in an exhaust pipe extending from an engine and a muffler connected to the exhaust pipe is known (for example, see Patent Document 1). In this type of vehicle exhaust system, there has been proposed a type in which a rear portion of an exhaust pipe is introduced into a muffler, and the rear portion of the exhaust pipe is expanded rearward in order to improve engine performance.
JP-A-6-10659

By the way, in the conventional exhaust apparatus mentioned above, when a catalyst was provided in the muffler for exhaust purification, there was a problem that the muffler was enlarged depending on the arrangement.
Further, in the case where a catalyst is provided in the muffler, further activation of the catalyst in the cold state immediately after the start of traveling has been desired.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle exhaust device that can solve the above-described problems of the prior art and promote catalyst activation in a cold state without increasing the size of a muffler connected to an exhaust pipe. There is to do.

  The present invention is an exhaust system for a vehicle in which a muffler is connected to an exhaust pipe extending from an engine, and includes a plurality of catalysts, and is located in the vicinity of the engine in a part of an exhaust pipe connected to the muffler, A bent portion including an upstream catalytic converter, a downstream catalytic converter, and a bent pipe that connects the catalytic converters in series is formed.

In the present invention, the bent portion constituting a part of the exhaust pipe is composed of the upstream side catalytic converter, the downstream side catalytic converter, and the bent pipe connecting the catalytic converters in series. Increasing the size of the muffler due to the built-in is suppressed.
In addition, since each catalytic converter is compactly incorporated into a bent portion constituting a part of the exhaust pipe, each catalytic converter can be easily installed in a narrow space near the engine of a motorcycle, for example. In addition, each catalytic converter is provided in the exhaust pipe that forms the bend upstream of the muffler and is located in the vicinity of the engine. Therefore, even in the cold state immediately after the start of running, the activation of the catalyst is accelerated by the latest engine heat. Is done.

In this case, the catalytic converters constituting the bent portion may be arranged side by side directly under the engine. In this configuration, it is possible to arrange the catalytic converter that effectively uses the space directly under the engine, and the efficiency of the arrangement space is improved, and the catalyst body is arranged near the center in the vehicle width direction. The weight balance is also good.
Moreover, you may arrange | position each catalytic converter which comprises the said bending part ahead of a driver | operator's step. According to this, the space in front of the driver's step is effectively used, and the weight balance of the vehicle is further improved.

Furthermore, each catalytic converter constituting the bent portion may be arranged on the inner side in the vehicle width direction of the leg shield. In this configuration, since the temperature inside the leg shield in the vehicle width direction rises within a relatively short time after the engine is started and before the start of running, each catalytic converter is more easily activated. Further, the space on the inner side in the vehicle width direction of the leg shield is effectively used, and the weight balance of the vehicle is also improved.
An exhaust pipe protector may be disposed on the open side of the exhaust pipe constituting the bent portion. In this configuration, since the open side of the exhaust pipe is covered with the protector, it is preferable in appearance.

  The upstream catalytic converter and the downstream catalytic converter are arranged in a single outer cylinder material so that the respective catalyst carriers are arranged substantially in parallel along the axis of the outer cylinder material and press the outer surface of the outer cylinder material. By doing so, the outer cylinder material may be deformed so that a predetermined range between the inner surface thereof and the outer surface of the catalyst carrier is in close contact, and at least a part thereof is brazed. In this configuration, since a plurality of catalyst carriers can be held by one outer cylinder, the number of parts can be eliminated. Further, since brazing is not required outside the predetermined range of the catalyst carrier, the brazing material can be reduced.

In a method for manufacturing a catalytic converter in which a plurality of catalyst carriers are arranged substantially in parallel and arranged in a part of an exhaust pipe connecting an engine and a muffler, a single outer cylinder material is disposed along the axis of the outer cylinder material. A step of arranging a plurality of catalyst carriers so that the flow paths are substantially parallel, and pressing the outer surface of the outer cylinder material, thereby bringing the inner surface of the outer cylinder material and the outer surface of the catalyst carrier into close contact with each other, A step of holding the catalyst carrier on the inner surface of the outer cylinder material; and a step of supporting the catalyst on the catalyst carrier in a state where the catalyst carrier is held on the outer cylinder material.
In this configuration, even when the catalyst is supported on a plurality of catalyst carriers, a single supporting step is required, and therefore the number of steps can be reduced.

In the present invention, since the bent portion constituting a part of the exhaust pipe is composed of the upstream side catalytic converter, the downstream side catalytic converter, and the bent pipe connecting the respective catalytic converters in series, the catalyst having a large capacity in the muffler. Increasing the size of the muffler due to the built-in is suppressed.
In addition, since each catalytic converter is compactly incorporated in a bent portion constituting a part of the exhaust pipe, each catalytic converter can be easily installed in a narrow space near the engine of a motorcycle, for example.
Furthermore, each catalytic converter is provided in the exhaust pipe that forms the bent portion upstream of the muffler, and these are arranged in the vicinity of the engine. Therefore, even in the cold state immediately after the start of traveling, the catalyst is activated by the latest engine heat. Promoted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(1) First Embodiment In FIG. 1, reference numeral 1 denotes a motorcycle (vehicle). The motorcycle 1 is configured by covering a front portion of a press frame 7 with a cover 2. A front fork 5 that supports the front wheels 4 is supported on the head tube 3 at the front of the press frame.

  An engine 6 is mounted on the lower middle part of the cover 2, and a fuel tank or the like (not shown) is provided on the inner side behind the cover 2. A sheet 8 is extended above. A rear fork 10 that supports the rear wheel 9 is swingably supported below the press frame 7, and a rear cushion unit 11 is interposed between the rear fork 10 and the rear portion of the frame. A handle 12 is attached to the upper part of the steering stem extending on the head tube 3, a headlight unit 13 is attached to the center of the handle 12, and blinker lamps 14 are provided on the left and right of the handle 12. It is attached.

  Leg shields 15 constituting the front part of the cover 2 are provided on the left and right sides of the front part of the motorcycle 1, and the leg shields 15 are integrally enclosed from the driver's feet right and left to the upper side of the head tube 3. Is formed. An intermediate portion of the leg shield 15 is curved backward so as to surround the rear portion of the head tube 3, and a vertical hook-shaped top cover 16 is disposed at the front portion of the head tube 3 positioned there. 16 is fixed to an intermediate portion of the leg shield 15.

  In this embodiment, the engine 6 is supported by the lower part 7a of the press frame 7 via the two hanger bolts 21, as shown in FIG. One end 23 a of an exhaust pipe 23 is connected to the exhaust port 6 b of the cylinder head 6 a of the engine 6 via a connecting flange 22. The exhaust pipe 23 is led out below the engine 6 and meanders in a substantially horizontal plane directly under the engine 6. A bent portion 31 is formed in the meandering portion, and a lead-out portion 23 b that leads to the rear of the vehicle body is formed. Then, the exhaust pipe 23 is connected to a muffler 25 as a so-called silencer at a rear end portion 23c.

The bent portion 31 constitutes a part of the exhaust pipe 23, and as described above, is positioned so as to be within the width of the engine 6 immediately below the engine 6, and is arranged with an axis extending in the width direction of the vehicle. An upstream catalytic converter 33, a downstream catalytic converter 35 having an axis extending in the width direction of the vehicle, and a substantially U-shaped bent pipe 37 connecting the converters 33 and 35 in series. It is configured with.
The present embodiment is characterized by the catalyst layout of the motorcycle, and the bent portion 31 is substantially U-shaped as a whole, and is disposed in the vicinity of and directly below the engine 6.
Here, the overall shape of the bent portion 31 is not limited to a substantially U shape. For example, as shown in FIG. 4, the upstream side catalytic converter 133, the downstream side catalytic converter 135, and a substantially V-shaped bent tube. 137, and may have a substantially V-shaped arrangement as a whole, or a substantially N-shaped arrangement using three catalytic converters, and a substantially M-shaped arrangement using four catalytic converters. It is good also as an arrangement | sequence etc.

A three-way catalyst is used for each of the catalytic converters 33 and 35. This three-way catalyst removes hydrocarbons, carbon monoxide, and nitrogen monoxide in the exhaust gas of the engine 6 by oxidation and reduction reactions. For example, as shown in FIG. 5, a converter main body 81 containing a honeycomb structure 83 coated with platinum, palladium, rhodium, etc., or a converter main body 85 as shown in FIG. In addition, a punching pipe 87 connected to the exhaust pipe 23 is inserted and fixed, and platinum, palladium, rhodium or the like supported on the punching pipe 87 is proposed.
These configurations are merely examples, and the present disclosure is not limited thereto, and other configurations may be used. In addition, among the catalytic converters 33 and 35, for example, the converter having the configuration shown in FIG. 5 may be adopted for one converter, and the converter having the configuration shown in FIG. 6 may be adopted for the other converter. It is.
In addition, a punching plate carrying a catalyst may be attached to, for example, the bottom of the bent tube 37 to perform auxiliary purification.

The three-way catalyst generally has a small ability to react and purify hydrocarbons until reaching the activation temperature (about 300 ° C.), and when the temperature is reached, the ability becomes high.
In this configuration, since each of the catalytic converters 33 and 35 is disposed in the vicinity of the engine 6, the heat of the engine 6 makes it easy for the temperature of the three-way catalyst to reach the activation temperature. Even in the cold state, the heat is received from the engine 6 and the temperature is raised within a relatively short time, and the three-way catalyst is quickly activated.

In this configuration, since the bent portion 31 constituting a part of the exhaust pipe 23 includes the upstream side catalytic converter 33 and the downstream side catalytic converter 35, the catalyst having a large capacity is built in the muffler 25. The increase in size of the muffler 25 is suppressed.
In addition, since each of the catalytic converters 33 and 35 is incorporated in a compact manner with respect to the bent portion 31 that constitutes a part of the exhaust pipe 23, for example, while ensuring a sufficient capacity of the catalyst of each of the catalytic converters 33 and 35, for example It can be easily and compactly installed in a narrow space near the engine of a motorcycle.

  In this configuration, since the catalytic converters 33 and 35 are arranged immediately below the engine 6, it is possible to effectively use the space and to arrange the catalytic converters 33, 35 without increasing the overall width of the vehicle. Since the arrangement 35 is difficult to appear on the appearance, the vehicle body design is not affected. Further, since the catalytic converters 33 and 35 are arranged directly under the engine, the position of the center of gravity is lowered, and since the catalytic converters 33 and 35 are arranged near the center portion in the vehicle width direction, the weight balance of the vehicle can be optimized.

In this case, as shown in FIG. 3, an under guard 39 is provided directly below the catalytic converters 33 and 35 so as to cover almost the entire area of the bent portion 31 including the converters 33 and 35 from below. The under guard 39 is fixed to the bosses 33a and 35a through bolts 39a, and the bosses 33a and 35a are welded to the outer walls of the catalytic converters 33 and 35, respectively. The under guard 39 is formed with a receiving groove 39b for receiving the head of the bolt 39a. The head of the bolt 39a does not protrude from the lower surface of the under guard 39. In this configuration, the bent portion 31 can be protected and the activation temperature of the catalyst can be easily reached.
The catalytic converters 33 and 35 are arranged side by side directly under the engine 6, and both are arranged with their axes substantially horizontal.

As shown in FIG. 2, a step shaft 41 is fixed to the lower surface of the engine 6 with screws, and driver steps 43 are disposed at both ends of the step shaft 41.
And in this structure, the bending part 31 containing each catalytic converter 33 and 35 is arrange | positioned ahead of the driver | operator's step 43. FIG.
According to this, the driver's foot contact is avoided, the influence on the driver's heat is suppressed to be relatively small, the space in front of the step 43 is effectively used, and the weight balance of the vehicle is optimized. Is planned.

The bent portion 31 including the catalytic converters 33 and 35 is disposed on the inner side in the vehicle width direction of the leg shield 15 at the front portion of the cover 2.
At the inner side in the vehicle width direction of the leg shield 15, the ambient temperature is likely to rise relatively. Therefore, the air temperature inside the leg shield 15 in the vehicle width direction rises within a relatively short time even after the engine 6 is started and before the start of traveling.
In this configuration, the catalytic converters 33 and 35 are heated by the air whose temperature has risen within this short period of time. Therefore, even after the engine 6 has been started, the catalytic converters 33 and 35 are in a state before starting running. Is easily activated.
Further, the space on the inner side in the vehicle width direction of the leg shield 15 is effectively used, and the weight balance of the vehicle is optimized.

In this configuration, the bent portion 31 is substantially U-shaped, and a discontinuous portion (open side 45) of the exhaust pipe 23 appears at a position facing the bent tube 37 as shown in FIG. The 1st exhaust pipe protector 47 which covers the said discontinuous part is arrange | positioned. The exhaust pipe protector 47 is fixed to a boss 23d through bolts 47a, and the bosses 23d are welded to the outer wall of the exhaust pipe 23, respectively. The exhaust pipe protector 47 is formed with a receiving groove 47b for receiving the head of the bolt 47a. The head of the bolt 47a does not protrude from the surface of the exhaust pipe protector 47.
In this configuration, since the open side 45 of the exhaust pipe 23 is covered with the exhaust pipe protector 47, the exhaust pipe 23 is protected and insulated, and the discontinuous portion of the exhaust pipe 23 is hidden in appearance. Therefore, it looks as if the exhaust pipe 23 is continuous from the outside of the vehicle, and the appearance is improved, which is preferable in appearance.
A second exhaust pipe protector 49 that covers the bent pipe 37 is disposed on the bent pipe 37 side. The exhaust pipe protector 49 is fixed to the bracket 23 e through a bolt 49 a, and the bracket 23 e is welded to the outer wall of the bent pipe 37. The exhaust pipe protector 49 is formed with a receiving groove 49b for receiving the head of the bolt 49a, and the head of the bolt 49a does not protrude from the surface thereof.
In this configuration, since the bent portion of the bent tube 37 is covered with the second exhaust pipe protector 49, the bent tube 37 is protected and insulated, and the bent portion is hidden from the outside, which is preferable in appearance. .

(2) Second Embodiment FIGS. 7 and 8 show a second embodiment.
In this embodiment, as shown in FIG. 7, the bent portion 231 constitutes a part of the exhaust pipe 23 and is positioned so as to be within the width of the engine 6 immediately below the engine 6. An upstream side catalytic converter 233 having an axial line extending in the direction thereof, a downstream side catalytic converter 235 having an axial line extending in the longitudinal direction of the vehicle, and a substantially U-shape in plan view that connects the converters 233 and 235 in series. And a bent tube 237 having a shape. In this case, as shown in FIG. 8, the catalytic converters 233 and 235 are arranged side by side directly below the engine 6 with their axes substantially horizontal, and the upstream catalytic converter 233 is connected to the downstream catalytic converter 235. The bent pipe 237, which is located slightly above the upper part and connects them in series, extends in a substantially U shape with the connection point A with the upstream side catalytic converter 233 at the upper side, and then lower than the connection point A. Is connected to the downstream catalytic converter 235 at the connection point B.

As shown in FIG. 7, the bent portion 231 has a substantially O-shape in plan view as a whole, and is disposed in the vicinity of and directly below the engine 6. 39 is an under guard. Here, the overall shape of the bent portion 231 is not limited to a substantially U shape. For example, when the number of catalytic converters is three, the shape is substantially N-shaped. It may be a letter shape or the like.
Note that a three-way catalyst is used for each of the catalytic converters 233 and 235 as in the above embodiment. Since the other configuration is substantially the same as the configuration of the above embodiment, the description thereof is omitted.

Also in this embodiment, since the catalytic converters 233 and 235 are arranged in the vicinity of the engine 6, for example, even in a cold state, the heat is received from the engine 6 and the temperature is raised within a relatively short time. The three way catalyst is activated quickly.
Further, since the bent portion 231 constituting a part of the exhaust pipe 23 includes the upstream catalytic converter 233 and the downstream catalytic converter 235, the muffler 25 is provided by incorporating a catalyst with a large capacity in the muffler 25. Increase in size is suppressed.
Further, since each of the catalytic converters 233 and 235 is incorporated in a compact manner with respect to the bent portion 231 constituting a part of the exhaust pipe 23, for example, while sufficiently ensuring the capacity of the catalyst of each of the catalytic converters 233 and 235, for example It can be easily and compactly installed in a narrow space near the engine of a motorcycle.

(3) Third Embodiment The present invention is not limited to the above-described configuration, and can be modified as follows.
FIG. 9 is a view showing an exhaust device for a vehicle according to the third embodiment.
In the third embodiment, just below the engine 6, the bent portion 331 includes an upstream catalytic converter 333, a downstream catalytic converter 335, and a bent tube 337 having a substantially U shape in plan view that connects the converters in series. I have. In this configuration, the upstream catalytic converter 333 and the downstream catalytic converter 335 are integrally formed, and the composite catalytic converter 36 is formed. The composite catalytic converter 36 is configured by a converter portion 36c and connecting portions 36j provided at both ends of the converter portion 36c. The converter portion 36 c is a portion that functions as a catalyst, and the connecting portion 36 j is a joint portion with the exhaust pipe 23 and the bent portion 331.

FIGS. 10A and 10B show a forming procedure of the converter portion 36c.
As shown in FIG. 10B, the converter portion 36c is formed by covering a pair of honeycomb structures 83 carrying a three-way catalyst with an outer cylinder 38 made of, for example, a stainless steel plate. Note that only a part of the honeycomb portion of the honeycomb structure 83 is illustrated.

  In manufacturing the converter portion 36c, first, as shown in FIG. 10A, an outer cylinder material 38c is prepared, and inside the outer cylinder material 38c, a pair of honeycomb structures 83 are provided with the outer cylinder material 38c. Are arranged substantially parallel to each other. The inner diameter W of the long diameter portion of the outer cylinder material 38c is formed to be slightly larger than the sum of the diameters of the honeycomb structure 83, and the inner peripheral length of the outer cylinder material 38c is a pair of honeycombs disposed therein. The structure 83 is formed to be shorter than the total outer peripheral length.

After the pair of honeycomb structures 83 are arranged inside the outer cylinder material 38c, as indicated by the arrow P, they are pressed from outside with a predetermined load. This pressing position is desirably the wall portion 38d of the outer cylinder material 38c located near the tangent line at the contact point T between the honeycomb structures 83. By this pressing, as shown in FIG. 10B, the outer cylinder material 38c is deformed, and the inner surface thereof is in close contact with the outer surface of the honeycomb structure 83, and the close contact portions are joined by brazing.
In a range where the inner surface of the outer cylinder material 38c and the outer surface of the honeycomb structure 83 are not in close contact, that is, in the non-brazing range D shown in FIG. 10B, as shown in FIG. Is provided. One end of the separator 84 reaches the opening end of the converter portion 36c, but the other end does not reach the honeycomb structure 83, and a gap δ is provided. This is to prevent contact between the separator 84 and the honeycomb structure 83 due to thermal expansion even during operation of the engine 6. In this configuration, since the outer cylinder 38 is longer in the flow path direction than the honeycomb structure 83, the separator 84 is provided. However, when the length of the outer cylinder 38 and the honeycomb structure 83 is substantially the same, It is not necessary to provide the separator 84.

The axial range of the coupling range by brazing may be brazed over the entire axial range, but as shown by the oblique lines in FIG. 11, a partial range, that is, the upstream catalytic converter 333 and the downstream catalytic converter 335 You may braze only the axial direction coupling | bonding range L which is the exit side (each downstream of f1 and f2) of the exhaust flow path in the honeycomb structure 83 arrange | positioned, respectively.
This type of converter section 36c has a higher temperature at the exhaust gas inlet side than at the outlet side. The partial range is combined in this manner. When the outlet side is brazed, the thermal stress generated in the brazed portion is lower than when the inlet side is brazed, and the durability of the converter portion 36c is improved. Because.

  The honeycomb structure 83 is a metal structure. For example, a plurality of cells are formed in a corrugated cardboard form by rolling a flat plate and a corrugated plate made of stainless steel 20 to 50 μm in a roll shape from one end. It is a cylindrical shape in which flat plates and corrugated plates are alternately laminated. The wound honeycomb structure 83 is coated or attached with a brazing material between flat plates and corrugated plates on both end surfaces thereof. And a flat plate and a corrugated sheet are fixed by heat-processing this. The brazing position may be only on the outlet side of the exhaust passage in the honeycomb structure 83 (the downstream side of each of f1 and f2), or may be the entire range in the axial direction. These configurations are examples of the honeycomb structure 83, and are not limited thereto. For example, other configurations such as a punching pipe 87 or a ceramic honeycomb may be used as the catalyst support.

  When the honeycomb structure 83 and the separator 84 are held by the outer cylinder 38, the honeycomb structure 83 is coated (supported) with platinum, palladium, rhodium, or the like. Then, the connecting portion 36j is connected to the outer cylinder 38, and the bent pipe 337 and the exhaust pipe 23 are connected to the connecting portion 36j, and the composite catalytic converter 36 is incorporated into the bent portion 331.

When the composite catalytic converter 36 is incorporated in the bent portion 331, the exhaust pipe 23 extending from the engine 6 communicates with the muffler 25 through the bent portion 331. Exhaust gas flowing into the bent portion 331 from the exhaust pipe 23 flows through the upstream side catalytic converter 333 of the converter portion 36c, as indicated by an arrow f1 in FIG. When flowing through the upstream catalytic converter 333, the exhaust flowing in from the exhaust pipe 23 is purified by the honeycomb structure 83 that constitutes the upstream catalytic converter 333. Exhaust gas purified by the upstream catalytic converter 333 passes through a bent pipe 337 communicating with the upstream catalytic converter 333 and the downstream catalytic converter 335, as shown by an arrow f2 in FIG. Circulate. When flowing through the downstream catalytic converter 335, the exhaust gas flowing from the upstream catalytic converter 333 is further purified by the honeycomb structure 83 constituting the downstream catalytic converter 335.
As described above, the exhaust gas purified by the bent portion 331 flows to the outlet portion 23b and is released from the muffler 25 to the atmosphere.

(4) Fourth Embodiment FIG. 12 is a view showing an exhaust device for a vehicle according to a fourth embodiment.
In the fourth embodiment, the bent portion 431 includes a composite catalytic converter 36 in which an upstream catalytic converter 433 and a downstream catalytic converter 435 are integrally formed. Similarly to the second embodiment, the upstream catalytic converter 433 and the downstream catalytic converter 435 are formed so that the axes extend in parallel in the longitudinal direction of the vehicle. The flow direction of the exhaust gas flowing through each converter in the bent portion 431 is the same as that in the second embodiment, and the bent portion 431 is configured together with the bent tube 437 having a substantially U shape in plan view that connects the converters in series. To do.

According to the third embodiment and the fourth embodiment, since the plurality of honeycomb structures 83 can be held by one outer cylinder 38, the upstream and downstream honeycomb structures 83 are not separately required to be bent and bent. The number of parts of the part 331 (431) can be reduced.
In addition, since it is not necessary to braze the honeycomb structure 83 and the outer cylinder 38 in a range other than the predetermined range (non-brazing range D), the brazing amount can be reduced. Further, since the plurality of honeycomb structures 83 are arranged in the outer cylinder 38, when the honeycomb structure 83 is coated with a catalyst, each honeycomb structure 83 is not coated in a separate supporting step, but once. It can be coated in a loading process. Thereby, a part of carrying process can be reduced.

  In this configuration, since the catalytic converter is arranged in a so-called dead zone directly under the engine 6, it is possible to effectively use the space and to arrange it without increasing the overall width of the vehicle. Since the converters 233 and 235 are arranged so that they do not appear on the exterior, the vehicle body design is not affected, the position of the center of gravity is lowered, and the converter is arranged near the center in the vehicle width direction. Figured.

As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this. For example, in the above-described embodiment, the catalyst layout of the motorcycle has been described. However, the present invention can also be applied to catalyst layouts of three-wheeled vehicles and four-wheeled vehicles classified as other ATVs (terrain traveling vehicles).
In the present embodiment, two honeycomb structures are used, but not limited to this, three or more honeycomb structures may be used.

  In the third embodiment and the fourth embodiment, the upstream and downstream honeycomb structures are arranged so as to be in contact with each other. However, the present invention is not limited to this. A longer length may be used, and the upstream honeycomb structure and the downstream honeycomb structure may be spaced apart from each other.

1 is a side view of a vehicle according to an embodiment of the present invention. It is a bottom view of the vehicle shown in FIG. It is the side view. It is a figure which shows another embodiment. It is a structural diagram of a catalytic converter. It is the structure figure of a catalytic converter similarly. FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment. FIG. 4 is a view corresponding to FIG. 3 showing a second embodiment. FIG. 9 is a view corresponding to FIG. 2 showing a third embodiment. It is a figure which shows the shaping | molding procedure of the converter part of a composite catalyst converter, (a) is a figure which shows an outer cylinder raw material deformation | transformation, (b) is XX sectional drawing which shows an outer cylinder raw material after deformation | transformation. It is sectional drawing of a composite catalytic converter. FIG. 9 is a view corresponding to FIG. 2 showing a fourth embodiment.

Explanation of symbols

6 Engine 15 Leg shield 23 Exhaust pipe 25 Muffler 31 Bending part 33, 133, 233, 333, 433 Upstream catalytic converter 35, 135, 235, 335, 435 Downstream catalytic converter 37, 137, 237, 337, 437 Bending pipe 38 outer cylinder 38c outer cylinder material 39 under guard 43 step 47 first exhaust pipe protector 49 second exhaust pipe protector 83 honeycomb structure (catalyst carrier)

Claims (7)

  An exhaust system for a vehicle in which a muffler is connected to an exhaust pipe extending from an engine, and includes a plurality of catalysts, and is located in the vicinity of the engine at a part of the exhaust pipe connected to the muffler, and an upstream side catalytic converter And a bent portion including a downstream catalytic converter and a bent pipe connecting the catalytic converters in series.   2. The exhaust system for a vehicle according to claim 1, wherein the catalytic converters constituting the bent portion are arranged side by side immediately below the engine.   The exhaust system for a vehicle according to claim 1 or 2, wherein each catalytic converter constituting the bent portion is arranged in front of a driver's step.   4. The vehicle exhaust device according to claim 1, wherein each of the catalytic converters constituting the bent portion is disposed on the inner side in the vehicle width direction of the leg shield. 5.   The exhaust device for a vehicle according to any one of claims 1 to 4, wherein an exhaust pipe protector is disposed on an open side of the exhaust pipe constituting the bent portion.   The upstream catalytic converter and the downstream catalytic converter are arranged in a single outer cylinder material so that the respective catalyst carriers are arranged substantially in parallel along the axis of the outer cylinder material and press the outer surface of the outer cylinder material. The outer cylinder material is deformed to bring a predetermined range between the inner surface thereof and the outer surface of the catalyst carrier into close contact with each other, and at least a part thereof is brazed. Vehicle exhaust system. In a method for manufacturing a catalytic converter in which a plurality of catalyst carriers are arranged substantially in parallel and arranged in a part of an exhaust pipe connecting an engine and a muffler, a single outer cylinder material is disposed along the axis of the outer cylinder material. A step of arranging a plurality of catalyst carriers so that the flow paths are substantially parallel, and pressing the outer surface of the outer cylinder material, thereby bringing the inner surface of the outer cylinder material and the outer surface of the catalyst carrier into close contact with each other, A catalytic converter comprising: a step of holding the catalyst carrier on an inner surface of the outer cylinder material; and a step of supporting the catalyst on the catalyst carrier in a state where the catalyst carrier is held on the outer cylinder material. Manufacturing method.

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