JP2009114954A - Exhaust system and method for manufacturing catalyst arranged in exhaust system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust system capable of surely suppressing a change in a flow rate of exhaust gas and the occurrence of a pressure loss. <P>SOLUTION: When assuming a passage area of an exhaust pipe 15 as S1, and a physical area excluding an area occupied by the catalyst 17 from a passage area of a storage section 16 as S2, the diameter D1 of the exhaust pipe 15 and the diameter D2 of the storage section 16 and the catalyst 17 are set so that the physical area S2 of the storage section 16 becomes larger than the passage area S1 of the exhaust pipe 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust device including an exhaust pipe connected to an engine, a large-diameter accommodating portion formed in the middle of the exhaust pipe, and a catalyst disposed in the accommodating portion, and a method for producing the catalyst. .

  In general, a catalyst employed in an exhaust device for a vehicle engine is formed by winding a metal corrugated plate to which a catalytic functional substance is attached, and has a multi-cylindrical honeycomb structure.

In order to arrange this type of catalyst in the exhaust passage, the diameter of the accommodating portion in which the catalyst is accommodated is made larger than the diameter of the other exhaust pipe so that the flow rate of the exhaust gas flowing through the exhaust passage and consequently the pressure loss does not occur. It is common to make it larger. Further, in order to make the flow velocity distribution of the exhaust gas flowing through the catalyst uniform, it has been proposed that the exhaust gas inflow surface of the catalyst be a convex surface (see, for example, Patent Document 1).
JP-A-10-118500

  By the way, as in the conventional exhaust device, simply setting the diameter of the housing portion to be larger than the diameter of the other exhaust pipes may cause changes in the flow rate of exhaust gas or non-uniform flow rate distribution, and consequently pressure. Loss may not be sufficiently suppressed.

  The present invention has been made in view of the above-described conventional situation, and an exhaust device that can suppress an increase in pressure loss due to a change in flow velocity or a flow velocity distribution of exhaust gas and manufacture of a catalyst disposed in the exhaust device. The challenge is to provide a method.

  The present invention relates to an exhaust system including an exhaust pipe connected to an engine, a storage part interposed in the middle of the exhaust pipe and having a diameter larger than the exhaust pipe, and a catalyst disposed in the storage part. When the passage area of the exhaust pipe is defined as S1, and the passage area of the accommodating portion obtained by subtracting the sectional area of the catalyst from the sectional area of the accommodating portion is defined as S2, the passage area S2 of the accommodating portion is the exhaust gas. It is characterized by being larger than the passage area S1 of the pipe.

  The present invention also relates to a method for producing a catalyst in which a corrugated metal plate to which a catalytic functional substance is adhered is wound in one direction to form a multiple cylindrical or elliptical cylinder, wherein the corrugated sheet is formed on the corrugated sheet. By winding in one direction from the central part in the winding direction, a multiple cylindrical shape or an elliptical cylindrical shape is formed.

  According to the exhaust device of the present invention, the passage area S2 obtained by removing the cross-sectional area of the catalyst from the cross-sectional area of the accommodating portion is made larger than the passage area S1 of the exhaust pipe, so that the substantial passage area of the accommodating portion is increased. It is possible to prevent the exhaust gas flow rate from increasing, and as a result, it is possible to suppress an increase in pressure loss when the exhaust gas flow passes through the catalyst.

  Further, according to the catalyst manufacturing method of the present invention, the corrugated plate made of metal to which the catalytic functional substance is attached is wound in one direction from the central portion in the winding direction of the corrugated plate. Compared with the conventional method of winding from, the time required for the production of the catalyst can be greatly shortened.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 to FIG. 7 are views for explaining an exhaust device according to an embodiment of the present invention and a method for producing a catalyst disposed in the exhaust device. In this embodiment, a motorcycle exhaust device will be described as an example.

  In the figure, reference numeral 1 denotes a scooter type motorcycle, which is supported by an underbone body frame 2 and a front end portion of the body frame 2 so as to be steerable left and right, and a front wheel 4 is provided at a lower end portion. A front fork 3 having a steering handle 5 disposed at the upper end, a unit swing type engine unit 6 supported by the vehicle body frame 2 so as to be swingable up and down, and a rear wheel 7 disposed at the rear end; A straddle-type seat 8 mounted above the engine unit 6 of the body frame 2.

  The vehicle body frame 2 is covered with a vehicle body cover 10, and a low floor type footboard 11 is disposed on the front lower side of the seat 8 of the vehicle body cover 10.

  The engine unit 6 integrates a four-cycle single-cylinder engine 6a and a transmission case 6b in which a V-belt type continuously variable transmission mechanism (not shown) that transmits power from the engine 6a to the rear wheel 7 is accommodated. Structure.

  An exhaust device 14 is disposed in the engine 6a. The exhaust device 14 includes an exhaust pipe 15 connected to the engine 6a, a muffler 18 connected to a downstream end of the exhaust pipe 15, and a tail pipe 19 connected to a rear end portion of the muffler 18. ing.

  In the middle of the exhaust pipe 15, an accommodating portion 16 having a larger diameter than the exhaust pipe 15 is interposed, and a catalyst 17 is disposed in the accommodating portion 16. The exhaust pipe 15 bends and extends from the lower wall portion of the engine 6a to the rear of the vehicle and is connected to the housing portion 16, and extends substantially linearly from the housing portion 16 to the rear of the vehicle. And a downstream exhaust pipe 15 b connected to the muffler 18. The downstream exhaust pipe 15b and the upstream exhaust pipe 15a have substantially the same diameter D1 over the entire length.

  The accommodating portion 16 connects a cylindrical accommodating portion main body 16a having a diameter D2 larger than the diameter D1 of the exhaust pipe 15, and the accommodating portion main body 16a to the upstream side exhaust pipe 15a and the downstream side exhaust pipe 15b. And a tapered upstream connection portion 16b and a downstream connection portion 16c.

  The accommodating portion 16 and the catalyst 17 are disposed in the vicinity of the upstream end of the exhaust pipe 15. This accelerates the activation of the catalyst 17 at the time of start-up and warm-up operation.

  The catalyst 17 includes a honeycomb body 20 (see FIG. 6) including a base plate 20a made of, for example, a stainless steel flat plate having a hexagonal shape shown in FIG. 7, and a corrugated plate 20b arranged and fixed on one surface of the base plate 20a. ) In one direction (B direction) to form a multiple cylinder (see FIG. 4).

  Catalytic functional substances such as alumina and noble metals are attached to the surfaces of the flat plates 20a and corrugated plates 20b in a layered manner.

  The catalyst 17 includes a columnar catalyst main body 17a located in the accommodating portion main body 16a of the accommodating portion 16, and a conical upstream catalyst connecting portion 17b located in the upstream connecting portion 16b and the downstream connecting portion 16c. And a downstream catalyst connecting portion 17c.

The distal end portion 17d of the upstream side catalyst connecting portion 17b of the catalyst 17 is arranged so as to substantially coincide with the boundary line a between the upstream side connecting portion 16b and the upstream side exhaust pipe 15a and substantially coincide with the passage center line b. Has been. Similarly, the rear end portion 17d of the downstream catalyst connection portion 17c substantially coincides with the boundary line a between the downstream connection portion 16c and the downstream exhaust pipe 15b and substantially coincides with the passage center line b. Is arranged.

  Here, the passage area (same as the cross-sectional area) of the exhaust pipe 15 is S1, the passage area of the housing portion excluding the cross-sectional area 17aS of the catalyst body 17a from the cross-sectional area 16aS of the housing body 16a, and S2. When the passage area of the connecting portion excluding the cross-sectional area 17aS of the catalyst main body 17a and the dead space area S2 'that does not substantially become a passage area from the cross-sectional area 16aS of the housing portion main body 16a is S3, the inner diameter of the exhaust pipe 15 D1 and the inner diameter of the accommodating body 16a, and thus the outer diameter D2 of the catalyst body 17a, are set such that the passage area S2 of the accommodating body 16a is larger than the passage area S1 of the exhaust pipe 15, and more preferably The passage area S3 is set to substantially coincide with the passage area S1 of the exhaust pipe 15 or to be larger than the passage area S1.

  The cross-sectional area of the catalyst 17 is the sum of the cross-sectional areas of the base plate 20a and the corrugated plate 20b, and the passage 20c portion is not included in the cross-sectional area of the catalyst.

  Further, the dead space area S2 ′ means an area of a layered portion in contact with the inner peripheral surfaces of a large number of catalyst passages 20c formed by the base plates 20a and the corrugated plates 20b of the honeycomb body 20 ( (See FIG. 5). That is, the flow velocity of the exhaust gas flowing through each catalyst passage 20c is the largest at the center of the passage 20c, and becomes smaller as it approaches the inner peripheral surface from the center, and the minute velocity contacting the base plate 20a and the corrugated plate 20b. It becomes substantially zero in the layered portion of the thickness. The exhaust gas flow velocity is zero, that is, the cross-sectional area of the layer portion having a small thickness in contact with the inner peripheral surface where the exhaust gas hardly flows is the dead space area S2 ′.

  Further, the passage area 16bS of the upstream connection portion 16b gradually increases from the passage area S1 of the exhaust pipe 15 to the passage area 16aS of the housing portion main body 16a. On the other hand, the cross-sectional area 17bS of the upstream catalyst connecting portion 17b gradually increases from zero to 17aS. Therefore, an upstream connection portion passage area S4 obtained by removing the cross-sectional area 17bS of the upstream catalyst connection portion 17b from the passage area 16bS of the upstream connection portion 16b substantially coincides with the passage area S2. The same applies to the downstream side connection portion 16c, and the downstream side connection portion passage area S5 of the downstream side connection portion 16c substantially coincides with the passage area S2.

  Next, a method for producing the catalyst 17 will be described with reference to FIG.

  As described above, the catalyst 17 is manufactured by winding the honeycomb body 20 to which the catalytic functional material is deposited in a layer shape in the B direction to form a multi-cylindrical shape.

  In the unfolded state, the base plate 20a has a hexagonal shape in which two opposing long sides of the four sides of the rectangle are formed so as to form an outwardly convex mountain shape. Then, the honeycomb body 20 is wound in the B direction from a straight line A portion connecting the vertices 20c 'and 20d' of the upper and lower two sides 20c and 20d. That is, the honeycomb body 20 is wound around the straight line A while overlapping the left and right side plate portions, and fixed so as to maintain a cylindrical state (see FIGS. 7A to 7C).

  In this way, the catalyst 17 having the columnar catalyst body 17a and the conical upstream catalyst connection portion 17b and the downstream catalyst connection portion 17c formed at both ends of the catalyst body 17a is formed.

  According to the exhaust device of the present embodiment, the passage area S2 obtained by removing the cross-sectional area 17aS of the catalyst main body 17a from the passage area 16aS of the housing main body 16a is more preferably larger than the passage area S1 of the exhaust pipe 14. The diameter D1 of the exhaust pipe and the diameter D2 of the accommodating portion 16 are set so that the passage area S3 obtained by removing the dead space area S2 'from the passage area S2 is substantially equal to the passage area S1 or larger than the passage area S1. Therefore, the flow rate of the exhaust gas in the accommodating portion 16 is not greatly changed compared to the upstream side and the downstream side, and an increase in pressure loss due to the arrangement of the catalyst can be suppressed.

  In the present embodiment, the tip end 17d of the upstream catalyst connecting portion 17b and the downstream catalyst connecting portion 17c located in the tapered upstream connecting portion 16b and the downstream connecting portion 16c is a boundary line a with the exhaust pipe 14. Since it is located so as to be located on the passage center line b, the passage areas S4 and S5 of the upstream connection portion 16b and the downstream connection portion 16c can be made substantially equal to the passage area S2 of the accommodating portion 16, and the exhaust gas is generated. Abrupt expansion can be avoided when flowing from the exhaust pipe 15a to the accommodating portion 16, and generation of pressure loss of the exhaust gas can be suppressed accordingly.

  According to the manufacturing method of the catalyst of the present embodiment, the upper and lower two sides 20c and 20d of the honeycomb body 20 facing each other are formed so as to form a convex chevron, and the apexes of the upper and lower two sides 20c and 20d are formed. Since the multi-cylindrical catalyst 17 is formed by winding in the B direction from the straight line A portion connecting 20c′20d ′, the productivity of the catalyst 17 can be increased. That is, the number of windings can be substantially halved as compared with the case of winding in one direction from one longitudinal end of the corrugated plate. In addition, when compared with a method in which the honeycomb body is folded in half at the central portion in the longitudinal direction and then wound in one direction from the bent portion, the bending process can be omitted, and the number of manufacturing steps can be reduced.

  Further, the upper and lower two sides 20c and 20d of the honeycomb body 20 are formed in a mountain shape, and only by winding this in one direction B, the upstream catalyst connecting portion 17b and the downstream catalyst connecting portion 17c can be formed simultaneously. The productivity of 17 can be further increased.

  8 to 11 are diagrams for explaining modifications of the embodiment. In the figure, the same reference numerals as those in FIGS. 2 and 7 denote the same or corresponding parts.

  FIG. 8 is a view for explaining the first modification, and this is a case where the downstream side exhaust pipe 15b of the exhaust pipe 15 has the same diameter D2 as that of the accommodating portion 16. FIG. In this case, the downstream catalyst connection part of the catalyst 17 is unnecessary.

  When the catalyst 17 of the first modification is manufactured, only one side 20c of the honeycomb body 20 is formed in a mountain shape, and the other side 20e is linear (see the two-dot chain line in FIG. 7A). You just have to wind from. Even in this case, the same effect as the above embodiment can be obtained.

  FIG. 9 is a diagram for explaining the second modification example, in which the upstream side catalyst connecting portion 17b and the downstream side catalyst connecting portion 17c of the catalyst 17 have a truncated cone shape. That is, the leading ends of the upstream catalyst connecting portion 17b and the downstream catalyst connecting portion 17c are flat surfaces 17b 'and 17c' that are perpendicular to the flow direction of the exhaust gas. In such a case, the disturbance of the exhaust gas can be alleviated.

  When manufacturing the catalyst 17 of the second modified example, as shown in FIG. 11, the upper and lower two sides 20c and 20d of the honeycomb body 20 are formed in a mountain shape, and the peak portions of the mountain shape are flat 20f and 20g. It is only necessary to wind in one direction B from the straight line A portion.

  FIG. 10 is a view for explaining a third modified example, in which the downstream exhaust pipe 15b of the exhaust pipe 15 has the same diameter D2 as the accommodating part 16, and the upstream catalyst connection part 17b of the catalyst 17 is conical. This is the case of a trapezoid. When the catalyst 17 is manufactured, the lower side 20d is linear (see the two-dot chain line in FIG. 11).

  In the above-described embodiment, the case where the catalyst has a multi-cylindrical shape has been described. However, as shown in FIG. 12, the present invention can also be applied to a catalyst 17 'having a multi-elliptical cylindrical shape. There are the same operations and effects as in the above embodiment.

  In the above embodiment, the exhaust device for a motorcycle has been described as an example. However, the exhaust device of the present invention is not limited to this and can be applied to an exhaust device for an automobile or the like.

1 is a side view of a motorcycle including an exhaust device according to an embodiment of the present invention. It is a cross-sectional block diagram of the said exhaust apparatus. It is principal part sectional drawing of the catalyst arrange | positioned at the said exhaust apparatus. It is a cross-sectional view of the catalyst. It is a principal part enlarged view of the said catalyst. It is a figure for demonstrating the manufacturing method of the said catalyst. It is a figure for demonstrating the manufacturing method of the said catalyst. It is a figure of the 1st modification of the said exhaust apparatus. It is a figure of the 2nd modification of the said exhaust apparatus. It is a figure of the 3rd modification of the said exhaust apparatus. It is a figure which shows the manufacturing method of the catalyst by the said modification. It is a figure which shows the modification of the catalyst in the said embodiment.

Explanation of symbols

6a Engine 14 Exhaust device 15 Exhaust pipe 16 Housing portion 16a Housing portion main body 16b, 16c Connecting portion 17 Catalyst 17a Catalyst body 17b, 17c Catalyst connecting portion 17d Tip portion 20 Honeycomb body 20a Base plate 20b Corrugated plate 20c, 20d Length of base plate Side 20c ', 20d' Vertex A Straight line B One direction D1 Diameter of exhaust pipe D2 Diameter of housing part and catalyst diameter a Boundary line b Path center line S1 Passage area S2 of exhaust pipe Exclude cross-sectional area of catalyst from passage area of housing part Passage area S2 'Dead space area S3 Passage area S4, S5 obtained by further removing S2' from passage area S2

Claims (9)

An exhaust pipe connected to the engine;
An accommodating portion interposed in the middle of the exhaust pipe and having a larger diameter than the exhaust pipe;
An exhaust device comprising a catalyst disposed in the housing part,
When the passage area of the exhaust pipe is S1, and the passage area of the housing portion excluding the cross-sectional area of the catalyst from the cross-sectional area of the housing portion is S2,
The exhaust device according to claim 1, wherein a passage area S2 of the accommodating portion is larger than a passage area S1 of the exhaust pipe. The exhaust device according to claim 1,
When the passage area of the housing portion excluding the cross-sectional area of the catalyst and the dead space area that does not substantially become the passage area from the cross-sectional area of the housing portion is S3, the passage area S2 of the housing portion is An exhaust system characterized by being substantially coincident with the passage area S3 or larger than the passage area S3. The exhaust device according to claim 1,
The exhaust unit according to claim 1, wherein the storage unit includes a storage unit body having a diameter larger than that of the exhaust pipe, and a tapered connection unit that connects the storage unit body and the exhaust pipe. The exhaust device according to claim 3,
2. The exhaust apparatus according to claim 1, wherein the catalyst has a catalyst main body located in the accommodating portion main body and a tapered catalyst connecting portion located in the connecting portion. The exhaust device according to claim 4,
The exhaust device according to claim 1, wherein a tip end portion of the catalyst connection portion is located near a boundary line between the connection portion and the exhaust pipe and near a passage center line. The exhaust device according to claim 5,
The exhaust device according to claim 1, wherein a passage area S4 of the connection portion obtained by removing a cross-sectional area of the catalyst connection portion of the catalyst from a cross-sectional area of the connection portion substantially matches the passage area S1 of the exhaust pipe. A method for producing a catalyst, in which a metal corrugated sheet to which a catalyst functional substance is attached is wound in one direction to form a multiple cylindrical or elliptical cylinder,
A method for producing a catalyst, characterized in that the corrugated plate is wound in one direction from a central portion in the winding direction of the corrugated plate to form a multiple cylindrical shape or an elliptical cylindrical shape. In the manufacturing method of the catalyst of Claim 7,
The corrugated sheet has a hexagonal shape in which two long sides of a rectangle are formed so as to form a convex chevron outward, and the corrugated sheet is wound in one direction from a straight line portion connecting the two convexes. Thus, a method for producing a catalyst, characterized in that both ends are formed into a multiple cylindrical shape or an elliptical cylindrical shape having a tapered shape. In the manufacturing method of the catalyst of Claim 7,
The corrugated plate has a pentagonal shape in which one of the two long sides of the rectangle is formed so as to form a convex chevron outward, and the corrugated plate passes through the convex to the other long side. A catalyst manufacturing method characterized in that one end is tapered into a multiple cylindrical or elliptical cylindrical shape by winding in one direction from a straight portion orthogonal to the vertical direction.

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