KR100401948B1 - Exhaust purifying device of internal combustion engine - Google Patents

Abstract

In the exhaust purification apparatus, a thin steel plate 22 supporting catalytic metal is arranged at a substantially central portion on the cross section of an exhaust pipe 5 extending from the exhaust port 4 of the engine 3. In other words, by arranging the catalytic metal in a substantially central portion on the cross section of the exhaust pipe 5 having a high exhaust gas temperature, it is possible to sufficiently exhibit the purifying action of the exhaust gas and reduce the manufacturing cost.

Description

Exhaust purifying device of internal combustion engine

Conventionally, as an exhaust purifying device for an internal combustion engine, for example, an "exhaust gas purifying device for an internal combustion engine" disclosed in Japanese Patent Laying-Open No. 3-85316 and an exhaust gas purifying device disclosed in Japanese Patent Application Laid-open No. 4-287821 An exhaust purification device is known.

17 and 18, the exhaust pipe 100 is connected to the exhaust port of a small internal combustion engine mounted on a motorcycle or the like, and the exhaust pipe 100 is connected to the exhaust port of the small- An inner pipe 101 made of a perforated plate extending in the same direction as the exhaust pipe 100 is disposed in the inner wall of the exhaust pipe 100 and a carrier 102 containing a catalyst is disposed on the inner wall surface of the inner pipe 101 .

Japanese Patent Application Laid-Open No. 4-287821 discloses an exhaust purifying apparatus for a motorcycle as shown in Figs. 19, 20, and 21, in which exhaust mufflers (not shown) are attached to exhaust outlets of a small internal combustion engine mounted on a motorcycle or the like. And a catalytic tube 111 is disposed at a central portion of an end surface of the exhaust muffler 110. The catalytic body 112 is accommodated in the catalytic tube 111. [ The catalyst body 112 is formed by attaching a catalyst material to a catalyst element of a honeycomb structure.

Generally, in order to sufficiently exhibit the purifying action of the catalyst, it is necessary to activate the catalyst at a high temperature. However, in a small-sized internal combustion engine, it is not easy to raise the exhaust temperature to the extent that the catalyst is activated, and therefore, it is necessary to consider the catalyst temperature as high as possible. It is necessary to take this into account because the temperature of the exhaust flowing through the exhaust pipe is high at the center section of the section of the tube (that is, at the central part shown in the sectional view) and relatively low around the circumference of the tube.

However, in the "exhaust gas purifying apparatus for internal combustion engine" shown in FIGS. 17 and 18, since the catalyst-attached inner pipe 101 is arranged in the inner wall of the exhaust pipe 100, it is not easy to sufficiently exert the purifying function.

On the other hand, in the "exhaust purifying apparatus for a motorcycle" shown in FIGS. 19 to 21, the catalyst body 112 is arranged at the center section of the end face of the exhaust muffler 110. Since the exhaust temperature is relatively high, Do. However, the catalyst body 112 made of the catalytic element having a honeycomb structure has a larger pressure loss than the inner tube 101 made of a perforated plate as shown in FIGS. 17 and 18. The flow rate of the exhaust flowing through the exhaust muffler 110 becomes higher at the central portion of the cross section of the pipe, so that the pressure loss becomes larger. Therefore, the influence of the pressure loss on the performance of the internal combustion engine becomes large, and is a factor that can not be ignored in a low-power internal combustion engine such as a motorcycle. The structure in which the catalytic body 112 made of the honeycomb structure of the catalytic element is housed in the catalytic tube 111 is similar to the structure in which the inner pipe 101 is disposed in the exhaust pipe 100 Which is quite expensive.

The present invention relates to an improvement of an exhaust purification apparatus for purifying an exhaust gas discharged from an internal combustion engine, that is, an engine.

1 is a side view of a motorcycle equipped with an exhaust purifying apparatus for an internal combustion engine according to a first embodiment of the present invention,

FIG. 2 is a side view showing a first embodiment of an exhaust pipe according to the present invention,

3 is a sectional view taken along the line A-A in Fig. 2,

FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 3,

5 is a perspective view showing a first embodiment of the second exhaust purifying apparatus according to the present invention,

6 is a cross-sectional view taken along the line C-C in Fig. 2,

7 is a sectional view taken along the line D-D in Fig. 6,

FIG. 8 is a sectional view taken along the line E-E in FIG. 6,

Figs. 9A to 9E are explanatory diagrams showing the first embodiment of the second carrier according to the present invention,

FIGS. 10A to 10D are views showing a modified example of the first embodiment of the second carrier according to the present invention,

11A to 11H are diagrams showing a modified example of the support structure for the first embodiment of the second carrier according to the present invention,

12 is a perspective view of the second exhaust purifying apparatus according to the second embodiment,

FIG. 13 is a sectional view taken along the line F-F in FIG. 12,

FIG. 14 is a view showing a modified example of the second exhaust purifying apparatus according to the second embodiment,

15 is a sectional view taken along the line G-G in Fig. 14,

16A to 16E are schematic diagrams of the exhaust purifying apparatus according to the third embodiment,

FIG. 17 is a cross-sectional view of a conventional exhaust pipe,

FIG. 18 is a partial longitudinal sectional view of a conventional exhaust pipe,

19 is a plan view of a conventional exhaust muffler,

20 is a partial cross-sectional perspective view of a conventional exhaust purifying apparatus,

FIG. 21 is a longitudinal sectional view showing the structure of the vicinity of the conventional catalytic tube.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust purifying apparatus for an internal combustion engine which is (1) fully utilizable for purifying action, (2) has minimal influence on the performance of the internal combustion engine, and (3)

In the present invention, a thin steel plate for holding and holding a catalytic metal is arranged at a substantially central portion of a cross section of an exhaust pipe extending from an exhaust port of an internal combustion engine. Therefore, the catalytic metal is disposed in the approximately central portion of the cross section having a high exhaust temperature in the exhaust pipe, and the catalytic metal is activated, and the purifying action of the exhaust gas is sufficiently exhibited.

As the thin steel sheet, a hollow cylinder extending in the axial direction of the exhaust pipe makes the pressure loss when the exhaust passes, which is desirable.

The cylinder is composed of a perforated plate, and it is desirable to close the exhaust upstream side of the cylinder. That is, since the exhaust passes through the plurality of holes formed in the wall of the cylinder, the exhaust is brought into contact with the held metal catalyst contained in the front and rear faces of the second carrier. Therefore, the contact area between the exhaust gas and the metal catalyst is increased, so that the precise action of the exhaust gas is enhanced.

Further, the present invention is characterized in that a thin steel plate cylinder for extending and extending in the axial direction of the exhaust pipe and holding the catalytic metal is disposed at a substantially central portion of the end face of the exhaust pipe extending from the exhaust port of the internal combustion engine, (Partition plate) for blocking the passage between the thin steel cylinder and the exhaust pipe. That is, the partition plate intercepts the front and rear to regulate the pulsation of the exhaust gas in the internal combustion engine, and makes the flow substantially smooth. Therefore, the purifying ability of the exhaust purifying device is not changed, so that the purifying action is enhanced. In addition, a separate support member for supporting the thin steel plate cylinder is not required as a four-section plate for regulating the pulsation of the exhaust.

As the thin steel cylinder body, it is desirable to attach the thin steel plate body so as to be able to expand and contract in the axial direction with respect to the exhaust pipe, thereby absorbing the difference in the amount of thermal expansion between the thin steel cylinder body subjected to thermal expansion and the exhaust pipe.

Further, in the exhaust purifying apparatus for an internal combustion engine according to the present invention, a first carrier for holding a metal catalyst in the vicinity of an inner wall surface of an exhaust pipe extending from an exhaust port of the internal combustion engine is disposed, And a second carrier holding catalytic metal in the center thereof was disposed. In other words, since the carrier holding the catalytic metal in the vicinity of the inner wall surface of the exhaust pipe and the substantially central portion of the cross section is disposed, the purification performance of the exhaust gas is further improved without adversely affecting the performance of the internal combustion engine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the first embodiment will be described with reference to Figs. 1 to 9.

1, the motorcycle 1 is provided with a two-cycle engine (internal combustion engine) 3 near the center of the vehicle body 2, and an exhaust pipe 5 is connected to the exhaust port 4 of the engine 3 And the muffler 6 is connected to the rear portion of the exhaust device 5. [

FIG. 2 shows an exhaust pipe 5 according to the present invention. This exhaust pipe 5 is formed as a thin circular section with a thin steel plate and is connected to the exhaust port 4 of the engine 3 by a flange and has a first exhaust purification device 10, And a second exhaust purification device 20 on the exhaust downstream side are disposed. The first exhaust purification device 10 is a purification device at the front end, and the second exhaust purification device 20 is a purification device at the downstream end. The portion of the exhaust pipe 5 where the second exhaust purifying device 20 on the exhaust downstream side is disposed is larger in diameter than the other portion.

FIG. 3 shows a sectional structure of the first exhaust purifying apparatus 10. As shown in FIG. The first exhaust purifying device 10 is an inner pipe 11 disposed in the exhaust pipe 5. The inner pipe (11) is a cylindrical body extending in the same direction as the exhaust pipe (5) in association with the inner wall of the exhaust pipe (5) and is constituted by a perforated plate made of a thin steel plate. The inner tube 11 is fixed to the support member 13 so that one end 11a of the inner tube 11 is welded and fixed to the exhaust pipe 5 and the other end 11b is axially stretchable with respect to the exhaust pipe 5. [ . Therefore, it is possible to absorb the difference in the amount of elongation in the axial direction between the exhaust pipe 5 and the inner pipe 11 due to thermal expansion.

The inner pipe 11 is held with a noble metal having a catalytic function, such as platinum and rhodium, on the wall surface having the pores 11c (by attaching a solution containing a noble metal) to the middle portion of the exhaust pipe 5 And an air gap 5c is formed between the inner pipes 11.

As shown in FIG. 4, when the exhaust pipe 5 is divided in the radial direction, the inner pipe 11 is integrated with the inner pipe 11 by being welded.

The support member 13 is obtained by fixing a corrugated plate by means of spot welding, and has a wave shape in a circumferential direction. The supporting member 13 is elastically deformable in the radial direction with respect to the exhaust pipe 5 and can absorb a difference in the amount of elongation between the exhaust pipe 5 and the inner pipe 11 due to thermal expansion . The support member 13 may be a corrugated plate and is not limited to the above-described structure. For example, the support member 13 may have a ring-like structure formed by interposing a stainless steel wire.

Numerals " 14 and 14 " are a pair of protector divided in the radial direction to cover the exhaust pipe 5 which becomes high temperature. These protectors 14 and 14 are bolted to a plurality of nuts 15 welded to the outer circumferential surface of the exhaust pipe 5.

FIG. 5 shows a second exhaust purifying apparatus 20 according to the present invention. The second exhaust purifying device 20 is provided with a pair of first supports 21 and 21 disposed in the vicinity of the inner wall surface of the exhaust pipe 5 and has a substantially central portion { And the first supports 21 and 21 and the second support 22 extend in the axial direction of the exhaust pipe. The first support 21 and the second support 22 extend in the axial direction of the exhaust pipe.

The first supports 21 and 21 are formed into a pair of semicircular tubes divided in the radial direction and the second support 22 is a cylindrical member having a diameter smaller than that of the first supports 21 and 21. The first supports (21, 21) and the second support (22) are composed of a perforated plate made of a thin steel sheet. The first supports 21 and 21 and the second support 22 each contain a noble metal having a catalytic function such as platinum and rhodium on a wall surface having a plurality of holes 21a and 22c Application). The exhaust pipe 5 is of a size having a space with respect to the first supports 21 and 21.

6, a support member 23 for supporting one end 22a of the second carrier 22 in such a manner as to extend and retract axially with respect to the exhaust pipe is provided on the upstream side of the exhaust (left side in the drawing) Respectively. The support member 23 includes a cushion member 24 for supporting and supporting one end 22a of the second carrier 22, an annular holder 25 for accommodating the cushion member 24, 25) to the exhaust pipe (5). Therefore, a difference in axial expansion and contraction can be absorbed between the exhaust pipe 5 and the second carrier 22 accompanying thermal expansion.

Not only the second carrier 22 is supported on the exhaust downstream side (right side of the drawing) in the exhaust pipe 5 but a partition plate 27 is provided for the passage membrane between the second carrier 22 and the exhaust pipe 5 . The flange portion 27a of the partition plate 27 is fixed to the exhaust pipe 5 by plug welding and the end portion of the flange portion 27a of the flange portion 27a of the thin plate- (22b) of the second carrier (22) is inserted into the first carrier (27b) and fixed by welding. One end (exhaust upstream side) 22a of the second carrier 22 is closed by a cap 28. [

In Fig. 7, the cushion member 24 has a corrugated shape in the circumferential direction, and the corrugated plate is not cylindrical, but the polymerized surface is fixed by spot welding. The cushion member 24 is elastically deformable in the radial direction with respect to the exhaust pipe 5 and absorbs the difference in the amount of expansion and contraction between the exhaust pipe 5 and the second carrier 22 accompanying thermal expansion can do.

In Fig. 8, both ends of each pair of first supports 21 and 21 are welded by spot welding in the vicinity of the periphery of the exhaust pipe 5 divided in the radial direction.

Next, the assembling procedure of the second carrier 22 having the above-described structure will be described with reference to FIG. 6 and FIGS. 9A to 9E.

9A, the cap 28 is fitted to the one end 22a of the second carrier 22 and the one end 22a of the second carrier 22 and the cap 28 are engaged with each other, Is fixed by spot welding, and one end 22a is closed.

9C, the other end 22b of the second carrier 22 is inserted into the through hole 27b of the partition plate 27 and fixed by welding.

9D, the holder 25 containing the cushion member 24 (see FIG. 6) is inserted into the one end 22a of the second carrier 22 and assembled in the form of FIG. 9E.

Finally, the second carrier 22 of the type shown in FIG. 9E is positioned in the lower half of the exhaust pipe 5 on the semi-circular top as shown in FIG. 6, and the holder 25 is fixed to the previously fixed bracket 26, The upper and lower halves of the exhaust pipe 5 are welded and the exhaust pipe 5 and the flange portion 27a of the partition plate 27 are plug welded to complete the assembling work.

Next, the actions of the first exhaust purifying device 10 and the second exhaust purifying device 20 will be described with reference to FIG. 2 and FIG.

2, the exhaust of the engine is introduced from the one end 5a side of the exhaust pipe 5, and when passing through the first exhaust purification device 10, the exhaust gas of the noble metal And reaches the purified second exhaust purifying device 20. The exhaust purifying device 20 is a purifier.

As shown in Fig. 6, in the second exhaust purification apparatus 20, the exhaust flows from the left side of the drawing. However, since the one end 22a of the second carrier 22 is closed by the cap 28, the exhaust does not flow along the one end 22a.

The portion of the exhaust pipe 5 where the second exhaust purification apparatus 20 is disposed is larger in diameter than the other portions and the exhaust gas is shut off before and after the partition plate 27 so that the exhaust gas upstream side is the expansion chamber 29. Therefore, the pulsation of the exhaust gas from the expansion chamber (29) to the engine (3) is regulated to be a substantially flat steady flow. Thus, the exhaust flows in the direction of the arrow in FIG. 6, and the exhaust flowing in the vicinity of the pipe wall of the exhaust pipe 5 is cleaned by contact reaction with the noble metal contained in the first supports 21 and 21.

The exhaust gas passes through the plurality of holes 22c formed in the wall of the second carrier 22 and flows into the second carrier 22 and flows through the other end portion 22b to the downstream side of the exhaust pipe 5 on the exhaust side And released into the atmosphere. When the exhaust gas passes through the second carrier 22, the exhaust gas contacts and reacts with the noble metal contained in the second carrier 22 to be purified.

In this case, the exhaust passes through the plurality of holes 22c formed in the wall of the second carrier 22, so that the exhaust gas contacts the supported catalyst metal contained in the inside of the second carrier 22, The contact area becomes large, and the catalytic metal sufficiently exhibits the purifying action.

As described above, in order to sufficiently exhibit the purifying action of the catalyst, it is necessary to activate the catalyst at a high temperature. On the other hand, the temperature of the exhaust flowing through the exhaust pipe 5 is higher at the central portion of the cross section of the pipe. The second carrier 22 passes the relatively high-temperature exhaust flowing through the central portion of the end face of the exhaust pipe 5 in contact with the catalyst metal, so that the catalyst metal becomes hot and sufficiently activated, and sufficiently exhibits the purifying action. Since the second carrier 22 is made of a porous plate cylinder, the pressure loss when the exhaust passes therethrough is small, and the influence on the performance of the engine is small.

In this way, the exhaust gas reacts in contact with the noble metal held in the first and second supports 21, 21 and 22, and is purified, so that it is efficiently purified. Further, since the exhaust becomes a substantially smooth steady flow, the purifying ability of the second exhaust purifying device 20 is not fluctuated and is efficiently purified.

The second carrier 22 becomes higher in temperature than the exhaust pipe 5 due to reaction heat or the like. Since the second carrier 22 is fixed to the exhaust pipe 5 at the other end 22b of the second carrier 22 by the partition plate 27, the exhaust pipe 5 and the second carrier 22 ), The one end 22a is elongated in the direction of the white arrow, and absorbs the difference in elongation. The difference in the radial extension between the exhaust pipe (5) and the second carrier (22) is absorbed by the elastic deformation of the cushion member (24).

The second carrier 22 is formed by closing the upstream side of the exhaust gas, and may be configured as shown in Figs. 10A to 10D as an example.

10A to 10D show modified examples of the second carrier 22 according to the first embodiment.

10A is a configuration in which one end 22a of the second carrier 22 is closed by a porous plate cap 31 which expands toward the upstream side of the exhaust, and the porous plate body cap 31 is formed by press molding.

FIG. 10B shows a cap 32 formed by flattening the one end 22a of the second carrier 22.

10C, a plurality of perforated plate blades are spirally attached to one end portion 22a of the second carrier 22 to increase the passage resistance of the exhaust, and the plurality of perforated plate blades And a cap 33 as shown in Fig.

FIG. 10D shows a configuration in which one end 22a of the second carrier 22 is closed by a flat plate-like plate cap 34. FIG. Instead of attaching the flat plate-made perforated plate cap 34, it is also possible to constitute a plate-like cap having one end portion 22a itself bent toward the center of the second carrier 22, and to close the upstream side of the exhaust.

Each of the caps 31, 32, 33, and 34 shown in Figs. 10A to 10D has the same function as that of the first embodiment described above, The pressure loss becomes smaller than that of the first embodiment.

The support structure of the second carrier 22 is such that one side of the second carrier 22 is retractably supported in the axial direction with respect to the exhaust pipe 5 and the other is fixed to the exhaust pipe 5, 11A to 11H.

11A to 11H show modifications of the support structure of the second carrier 22 according to the first embodiment. The exhaust flows in the direction of the arrow in the drawing, and one end 22a of the second carrier 22 expands in the direction of the white arrow by thermal expansion.

The support structure of the second carrier 22 shown in FIG. 11A is a structure in which one end 22a of the second carrier 22 is extended to the upstream side of the exhaust from the support member 23, And the cap 28 is closed. The support structure of the second carrier 22 shown in Fig. 11B has a structure in which the cap 36 closes the exhaust upstream side (the left side in the figure) of the support member 23. The gap S ₁ between the one end portion 22a and the cap 36 is larger than the elongation amount due to the thermal expansion of the second carrier 22. In this case, it is not necessary to attach the cap to the one end 22a of the second carrier 22.

The supporting structure of the second carrier 22 shown in Fig. 11C has a configuration in which the receiving portion 25 of the supporting member 23 is longer in the axial direction of the exhaust pipe 5 than the bracket 26.

The supporting structure of the second carrier 22 shown in FIG. 11D has a configuration of a one-end support in which the second carrier 22 is supported by the partition plate 27. The support member 37 includes a cushion member 38 for supporting the other end portion 22b of the second carrier 22 in an axially extending direction of the exhaust pipe 5, And a partition plate 27 for fixing the storage portion 39 to the exhaust pipe 5. [ In between the flange (39a) of the other end (22b) and the housing (39) and the spacing (S _2), a gap (S ₂₎ is the amount of movement of the other end (22b) to the extent of the gap (S ₂₎ And the amount of elongation.

11E is a modification of the configuration of FIG. 11D, and the length of the cushion member 38 and the accommodating portion 39 is shorter than the configuration of FIG. 11D.

The supporting structure of the second carrier 22 shown in Fig. 11F is such that one end 22a of the second carrier 22 is fixed to the exhaust pipe 5 by the bracket 41 and the one end 22a of the second carrier 22 And the other end portion 22b is supported at both ends by the support member 42 so as to be stretchable in the axial direction of the exhaust pipe 5. [ The support member 42 includes a cushion member 43 for supporting the other end portion 22b of the second carrier 22 in an axially extending direction of the exhaust pipe 5, And a partition plate 27 for fixing the accommodating portion 44 to the exhaust pipe 5. And the other end 22b is extended toward the exhaust downstream side (the left side in this drawing) than the support member 42. [

The support structure of the second carrier 22 shown in Fig. 11G is a modified example of the structure of Fig. 11F. The cap 45 having the lock projection formed by cutting at one end 22a of the second carrier 22, So that the one end portion 22a is closed.

FIG. 11H is a modification of the cushion members 24, 38 and 43, and is a constitution of a cushion member 48 in which a stainless wire is embedded into a ring shape. The support member 46 is supported by the second support 22 in such a manner that the seat plate 47 wound on the other end portion 22b of the second support member 22 and the other end portion 22b, Two cylindrical cushion members 48 and 48 for retractably supporting the cushion members 48 and 48 and a cylindrical accommodating portion 49 for accommodating the cushion members 48 and 48. The accommodating portion 49 is connected to the exhaust pipe 5, And a separating plate 27 for fixing the separator 27 to the casing.

Next, a second embodiment of the second exhaust purifying apparatus will be described with reference to FIGS. 12 and 13.

12, the second exhaust purification apparatus 50 has a first support 51 disposed in the vicinity of the inner wall surface of the exhaust pipe 5, and a substantially central portion of the first support 51 (I.e., the approximate center portion of the cross section of the second carrier 52). The first carrier 51 and the second carrier 52 extend in the axial direction of the exhaust pipe 5.

The first carrier 51 is made of a cylindrical body and has conical portions 51a and 51a at both ends in the axial direction and one or both of the conical portions 51a and 51a are welded to the exhaust pipe 5 will be. The second carrier 52 is made of a flat plate, and one end or both ends in the longitudinal direction thereof is welded and fixed in the first carrier 51.

The first carrier (51) and the second carrier (52) are made of a thin plate made of a thin steel plate. The first support 51 and the second support 52 are supported on a wall surface having a plurality of holes 51c and 51c, respectively, with a noble metal having a catalytic function, such as platinum and rhodium, ).

FIG. 13 shows a second carrier 52 made of a flat plate in a straight line state in the first carrier 51.

Next, the operation of the second exhaust purification apparatus 50 according to the second embodiment will be described with reference to FIG. 12. FIG. The exhaust of the engine flows in the direction of the arrow in this figure and the exhaust flowing near the wall flows through the plurality of holes 51c drilled in the wall of the first carrier 51, Flows through a plurality of holes (52a) formed in the wall of the base (52). Therefore, the exhaust gas contacts and reacts with the noble metal contained in the first carrier 51 and the second carrier 52 to be purified.

In this case, since the exhaust gas passes through the plurality of holes 52a formed in the wall of the second carrier 52, the exhaust gas comes into contact with the catalytic metal contained in the front and rear surfaces of the second carrier 52, The contact area becomes large, and the catalytic metal sufficiently exhibits the purifying action.

The noble metal supported in the second carrier (52) is brought into contact with the relatively high temperature exhaust flowing through the center portion of the end surface of the exhaust pipe (5).

Since the second carrier 52 is formed of a flat plate drawn in the axial direction of the exhaust pipe 5, the pressure loss at the time of passing the exhaust gas becomes smaller than that of the first embodiment described above.

14 shows a modified example of the second exhaust purification apparatus 50 according to the second embodiment. The first carrier 51 is a broken circular cross-sectional shape in which a part of the diameter of the cylindrical body (for example, the lower part of FIG. 14) is notched.

In FIG. 15, the first carrier 51 is joined to the inner wall of the exhaust pipe 5 by folding back the flange portions 51b and 51b at both edges of the cut circular cross section. The second carrier (52) passes through the cutaway portion of the first carrier (51) and contacts the inner wall of the exhaust pipe (5).

16A to 16E schematically show the outline of the exhaust purification apparatus according to the third embodiment of the present invention.

16A, the exhaust purification apparatus 61 is provided with a two-stage purification apparatus in the front and rear stages in the exhaust pipe 5, and a control valve (for example, (A butterfly valve) 62 is interposed between them. The front end purification apparatus is the configuration of the first exhaust purification apparatus 10 shown in FIG. 3, and the downstream purification apparatus is the configuration of the second exhaust purification apparatus 50 shown in FIG. 12 to be.

The exhaust purification device 63 in FIG. 16B has a configuration in which three purification stages in the front and rear stages are arranged in the exhaust pipe 5. The front end purification apparatus is the configuration of the first exhaust purification apparatus 10 shown in FIG. 3, and the stop purification apparatus is the configuration of the second exhaust purification apparatus 50 shown in FIG. 12 And the purifying device at the rear end is a configuration of the lead-out pipe 64 extending from the other portion 5b of the exhaust pipe 5 into the exhaust pipe 5. This lead-out pipe 64 is made of a thin plate made of a thin steel plate, and is supported on a wall surface having a porous surface by supporting a noble metal having a catalytic function such as platinum and rhodium (by applying a solution containing a noble metal).

The exhaust purification device 65 in FIG. 16C has a structure in which a carrier 66 extending in the axial direction of the exhaust pipe 5 is disposed at a substantially central portion on the cross section of the exhaust pipe 5. The support 66 is a flat plate made of a thin plate made of a thin steel plate and supported by supporting a noble metal having a catalytic function such as platinum and rhodium on a wall surface having a plurality of holes (by applying a solution containing a noble metal).

The exhaust purifying device 67 in FIG. 16D is a modification of the exhaust purifying device shown in FIG. 16C, and the carrier 66 is a corrugated plate instead of a flat plate.

The exhaust purifying device 68 in FIG. 16E has a configuration in which a semicircular carrier 69 extending in the axial direction of the exhaust pipe 5 and having both ends in the axial direction closed is disposed. The carrier 69 has a radially open end 69a disposed at the approximate center of the cross section of the exhaust pipe 5. The carrier 69 is made of a thin plate made of a thin steel sheet and supports a noble metal having a catalytic function such as platinum and rhodium on a wall surface having a plurality of holes (by applying a solution containing a noble metal).

16C, 16D and 16E may be applied to a multi-stage purification apparatus arranged in the exhaust pipe 5 shown in FIGS. 16A and 16B.

In the first, second, and third embodiments and modified examples, the "thin steel plate" carrying the catalytic metal is disposed at the approximate center of the cross section of the exhaust pipe 5 or at the approximate center of the cross section of the first supports 21, 51 As a concrete example, in the first embodiment shown in Figs. 1 to 9 and the modified examples shown in Figs. 10 and 11, a second carrier 22 made of a perforated plate cylinder is constituted, and twelfth, In the modification shown in the second embodiment, the fourteenth and fifteenth drawings shown in Fig. 13, and the third embodiment shown in Figs. 16A and 16B, the second carrier 52 made of a perforated plate flat plate is constituted, In the third embodiment shown in Figs. 16C, 16D and 16E, supports 66, 69 made of perforated plate flat plate, corrugated plate or semi-flat plate are constituted.

In this way, the " thin steel sheet " in the present invention is not limited to the structure of each of the above embodiments and modifications thereof, and is not limited to the perforated plate, and the shape and size of the perforated plate, have.

As described above, according to the exhaust purification apparatus of the internal combustion engine of the present invention, the thin steel plate supporting the catalyst metal is disposed at the substantially central portion of the exhaust pipe extending from the exhaust port of the internal combustion engine. The catalytic metal can be activated to sufficiently exhibit the purifying action of the exhaust gas, and furthermore, it can be realized at a low cost.

Further, since the exhaust gas purifying apparatus of the internal combustion engine of the present invention uses a thin steel sheet as a cylinder extending in the axial direction of the exhaust pipe, there is an advantage that the pressure loss when the exhaust gas is passed is small and therefore the performance of the internal combustion engine is not affected I have.

Further, the exhaust purification apparatus of the internal combustion engine of the present invention is characterized in that the cylinder is formed of a perforated plate and the upstream side of the exhaust of the cylinder is closed, so that the exhaust passes through a plurality of holes formed in the wall of the cylinder, In contact with the supported catalyst metal. Accordingly, the contact area between the exhaust gas and the catalytic metal is increased, and the purifying action of the exhaust gas is further enhanced.

In addition, the exhaust purification apparatus of the internal combustion engine of the present invention is characterized in that a thin steel plate cylinder in which the catalytic metal is supported by extending in the axial direction of the exhaust pipe is disposed at a substantially central portion of the exhaust pipe extending from the exhaust port of the internal combustion engine, Since the catalytic metal is disposed at the approximate center of the section having a high exhaust temperature by supporting the thin steel cylinder and supporting the thin steel cylinder and a partition plate for blocking the passage between the exhaust pipe, The purifying action can be sufficiently exhibited, and the cost can be reduced. Further, since the partition plate prevents the exhaust gas from flowing back and forth, the pulsation of the exhaust gas in the internal combustion engine is regulated so as to make the flow smoothly smooth. Thus, the purifying ability of the exhaust gas purifying apparatus is not changed. In addition, since the thin steel plate cylinder is supported by the partition plate for regulating the pulsation of the exhaust, a separate support member is not required, and the support structure is simple.

Furthermore, the exhaust device of the internal combustion engine of the present invention can easily absorb the difference in expansion / contraction between the cylinder and the exhaust pipe due to the thermal expansion, by mounting the cylinder of the thin steel plate in the axial direction in the axial direction.

In addition, the exhaust apparatus of the internal combustion engine of the present invention is characterized in that a first carrier for supporting and supporting the catalytic metal is disposed in the vicinity of the inner wall surface of the exhaust pipe extending from the exhaust port of the internal combustion engine, Since the carrier supporting the catalyst metal is disposed at both the vicinity of the inner wall surface of the exhaust pipe and the substantially central portion of the exhaust pipe by disposing the second carrier for holding the metal therebetween, the exhaust purifying action can be performed without any influence on the performance of the internal combustion engine, It can be increased, and the cost can be reduced.

Particularly, by disposing the first carrier coaxially with the inner wall of the exhaust pipe, the temperature of the first carrier is increased and the purifying action of the catalyst is improved.

Claims (6)

And an exhaust pipe (5) extending from an exhaust port (4) of the internal combustion engine (3) and purifying the exhaust gas in the internal combustion engine (3), the internal combustion engine (3) A thin steel plate cylinder 22 which extends in the axial direction of the exhaust pipe 5 and is supported with a catalytic metal is disposed at a substantially central portion of the end face of the exhaust pipe 5 and the thin steel plate cylinder 22 22) and a partition plate (27) for closing the passage between the thin steel cylinder (22) and the exhaust pipe (5). The exhaust purification apparatus of an internal combustion engine according to claim 1, characterized in that the thin steel cylinder (22) is attached to the exhaust pipe (5) so as to be axially stretchable. And an exhaust pipe (5) extending from an exhaust port (4) of the internal combustion engine (3) and purifying the exhaust gas in the internal combustion engine (3), the internal combustion engine (3) A first carrier (21, 51) supported in the vicinity of the inner wall surface of the exhaust pipe (5) by supporting a catalytic metal is disposed, and a catalytic metal is supported in a substantially central portion of the first carrier The first supports 21 and 51 and the second supports 22 and 52 are disposed so as to be coaxial with each other at a substantially central portion of the large diameter portion of the exhaust pipe 5 Wherein the exhaust gas purifying apparatus is an exhaust gas purifying apparatus for an internal combustion engine. The exhaust purification apparatus of an internal combustion engine according to claim 3, wherein the second carrier (22) is made of a cylinder, the cylinder is a porous plate, and the upstream side of the exhaust gas is closed. The exhaust purification apparatus of an internal combustion engine according to claim 3, wherein the first carrier (51) is a cylindrical body and the second carrier (52) is a flat plate. The exhaust purification apparatus of an internal combustion engine according to claim 3, wherein the first support (21, 51) and the second support (22, 52) have a plurality of holes (21a, 51c, 22c, 52a) .

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