KR19980702977A - Exhaust purifier of internal combustion engine - Google Patents

Abstract

The exhaust purification apparatus arranges a thin steel plate 22 containing catalyst metal at a substantially central portion in the cross section of the exhaust pipe 5 extending from the exhaust port 4 of the engine 3. That is, by arranging the catalytic metal at approximately the center on the cross section of the exhaust pipe 5 having a high exhaust temperature, the exhaust gas purifying action can be sufficiently exhibited and the manufacturing cost can be reduced.

Description

Exhaust purifier of internal combustion engine

BACKGROUND ART Exhaust purification apparatuses for internal combustion engines include, for example, exhaust gas purification apparatuses for internal combustion engines disclosed in Japanese Patent Application Laid-open No. 3-85316 and exhaust gas purification apparatuses for motorcycles disclosed in Japanese Patent Application Laid-Open No. 4-287821. Is known.

In the exhaust gas purifying apparatus of the internal combustion engine of Japanese Patent Laid-Open No. 3-85316, according to FIGS. 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. The inner tube 101 made of a porous plate extending in the same direction as the exhaust pipe 100 is connected to the inner wall of the 100, and the carrier 102 containing the catalyst is attached to the wall surface of the inner tube 101. will be.

An exhaust purifying apparatus such as a motorcycle of Japanese Patent Laid-Open No. 4-287821 has an exhaust muffler (110) in an exhaust port of a small internal combustion engine mounted on a motorcycle, as shown in FIGS. 19, 20 and 21 degrees. , The catalyst tube 111 is disposed at the center of the end face of the exhaust muffler 110, and the catalyst body 112 is accommodated in the catalyst tube 111. The catalyst body 112 is a catalyst material attached to a catalyst element having a honeycomb structure.

In general, 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 internal combustion engine, it is not easy to raise the exhaust temperature to the extent that the catalyst is activated, and therefore, consideration of increasing the catalyst temperature as much as possible is required. This needs to be taken into account because the temperature of the exhaust gas flowing through the exhaust pipe is high at the center of the cross section of the pipe (ie, at the center shown in the cross section) and relatively low around the wall of the pipe.

However, in the exhaust gas purifying apparatus of the internal combustion engine shown in FIGS. 17 and 18, since the inner tube 101 with the catalyst is disposed due to the inner wall of the exhaust pipe 100, it is not easy to exert a purification effect sufficiently.

On the other hand, in the exhaust purification apparatuses such as motorcycles shown in FIGS. 19 to 21, the catalyst body 112 is disposed at the center of the end face of the exhaust muffler 110, and since the exhaust temperature is relatively high, it is easy to exert a purification effect. However, the catalyst body 112 composed of the honeycomb structured catalyst element has a larger pressure loss than the inner tube 101 made of the porous plate as shown in FIGS. 17 and 18. Since the flow velocity of the exhaust gas flowing through the exhaust muffler 110 is increased at the center of the end face of the pipe, the pressure loss is further increased. For this reason, the influence of pressure loss on the performance of the internal combustion engine is large, and it is a factor that cannot be ignored especially in a low power internal combustion engine such as a motorcycle. In addition, the structure which accommodated the catalyst body 112 which consists of a catalyst element of a honeycomb structure in the catalyst pipe 111 is the structure which arrange | positioned the inner pipe 101 in the exhaust pipe 100 as shown to FIG. 17 and 18 degree. It is quite expensive compared to this.

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

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

2 is a side view showing a first embodiment of the exhaust pipe according to the present invention;

3 is a cross-sectional view taken along the line A-A in FIG.

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

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

6 is a cross-sectional view taken along the line C-C in FIG.

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

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

9A to 9E are assembly explanatory diagrams showing a first embodiment of a second carrier according to the present invention;

10A to 10D are diagrams showing a modification of the first embodiment of the second carrier according to the present invention,

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

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

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

14 is a diagram showing a modification of the second exhaust purification apparatus according to the second embodiment,

15 is a cross-sectional view taken along the line G-G in FIG.

16A to 16E are schematic views of an exhaust purification apparatus according to the third embodiment,

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

18 is a partial longitudinal side 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 purification apparatus,

21 is a longitudinal sectional view showing a structure near a conventional catalyst tube.

An object of the present invention is to provide an exhaust purification apparatus for an internal combustion engine, which (1) exhibits a purifying action for ten minutes, (2) does not affect the performance of an internal combustion engine as much as possible, and (3) has a low cost.

According to the present invention, a thin steel sheet containing catalyst metal is disposed at approximately the center of the cross section of the exhaust pipe extending from the exhaust port of the internal combustion engine. Therefore, the catalyst metal is arranged at the substantially center portion of the cross section of the exhaust pipe having a high exhaust temperature, and the catalyst metal is activated to sufficiently exert the purifying action of the exhaust gas.

As the thin steel sheet, it is desirable to use a hollow cylinder extending in the axial direction of the exhaust pipe so that the pressure loss at the time of exhausting is reduced.

The cylinder is composed of a porous plate, and it is desired to close the exhaust upstream side of the cylinder. That is, since the exhaust passes through a plurality of holes formed in the wall of the cylinder, the exhaust comes into contact with the metal catalyst held in the front and rear surfaces of the second carrier. Therefore, the contact area between the exhaust gas and the metal catalyst becomes large, so that the correct action of the exhaust gas is increased.

In addition, the present invention is arranged in the center of the cross-section of the exhaust pipe extending from the exhaust port of the internal combustion engine in a thin-walled steel cylinder that extends in the axial direction of the exhaust pipe to hold the catalyst metal to hold the thin steel cylinder in the exhaust pipe In addition to supporting, a trimming plate for preventing a passage between the thin steel plate cylinder and the exhaust pipe was provided. That is, the trimming plate cuts off the front and rear, and regulates the pulsation of the exhaust gas in the internal combustion engine, and is generally smooth. For this reason, since the purification | cleaning capability does not change, an exhaust purification apparatus becomes high. In addition, a separate support member for supporting the thin steel plate cylinder with a trimming plate that regulates the pulsation of the exhaust is unnecessary.

The thin steel plate cylinder is desirably absorbed in the axial direction with respect to the exhaust pipe so as to absorb the difference in the amount of thermal expansion between the thin steel plate cylinder and the exhaust pipe accompanying thermal expansion.

Moreover, the exhaust purification apparatus of the internal combustion engine which concerns on this invention arrange | positions the 1st support body which hold | maintains a metal catalyst by extending the vicinity of the inner wall surface of the exhaust pipe extended from the exhaust port of this internal combustion engine, and roughly of the cross section of this 1st support body. The second carrier having the catalytic metal contained therein was arranged in the center. That is, since the carrier containing catalyst metal is arranged in both the inner wall surface of the exhaust pipe and in the substantially center part of the cross section, the purification of the exhaust gas is further improved without adversely affecting the performance of the internal combustion engine.

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.

In FIG. 1, the motorcycle 1 is provided with a two-cycle engine (internal combustion engine) 3 near the center of the vehicle body 2, and the exhaust pipe 5 is connected to the exhaust port 4 of the engine 3. As shown in FIG. Then, the silencer 6 is connected to the rear of the exhaust device 5.

2 shows an exhaust pipe 5 according to the present invention. The exhaust pipe 5 is formed of a thin steel plate in a circular cross section, and connects an exhaust port 4 (see FIG. 1) of the engine 3 with a flange, and has a first exhaust purification device 10 on the upstream side of the exhaust. And a second exhaust purification apparatus 20 on the exhaust downstream side. 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 rear end. In the exhaust pipe 5, the portion where the second exhaust gas purifying device 20 on the exhaust downstream side is disposed has a larger diameter than the other portions.

3 shows a cross-sectional structure of the first exhaust purification apparatus 10. The first exhaust gas purifying apparatus 10 is an inner tube 11 arranged in the exhaust pipe 5. The inner tube 11 is a cylindrical body extending along the inner wall of the exhaust pipe 5 and extending in the same direction as the exhaust pipe 5, and is composed of a thin steel plate porous plate. The inner tube 11 is fixed to the end portion 11a of the inner tube 11 by welding to the exhaust pipe 5 and the other end 11b is elastically stretchable in the axial direction with respect to the exhaust pipe 5. Supported. For this reason, the difference in the amount of extension in the axial direction between the exhaust pipe 5 and the inner tube 11 accompanying the thermal expansion can be absorbed.

The inner tube 11 holds a precious metal having a catalytic function such as platinum and rhodium on the wall surface having the pores 11c (attached a solution containing the precious metal by coating or the like). A gap 5c is formed between the middle portion of the exhaust pipe 5 and the inner tube 11.

As shown in FIG. 4, when the exhaust pipe 5 is divided in the radial direction, it becomes a semi-cylindrical shape, and is integrated by welding in the state which the inner pipe 11 was built.

The support member 13 is formed by spot welding a surface obtained by rolling a corrugate plate in a cylindrical shape and polymerizing it, and has a wavy shape in the circumferential direction. For this reason, the support member 13 can expand and contract in the radial direction with respect to the exhaust pipe 5 by elastic deformation, and can absorb the difference in the amount of expansion and contraction between the exhaust pipe 5 and the inner pipe 11 accompanying thermal expansion. The support member 13 is a corrugated board, and is not limited to the above configuration. For example, the support member 13 may be configured as a ring-shaped structure which is assembled with a stainless steel wire.

Nos. 14 and 14 are pairs of protectors divided in the radial direction to cover the exhaust pipe 5 which becomes hot. These protectors 14, 14 are bolted to a number of nuts 15 welded to the outer circumferential surface of the exhaust pipe 5.

5 shows a second exhaust purification apparatus 20 according to the present invention. The second exhaust purification apparatus 20 is arranged near the inner wall surface of the exhaust pipe 5 to arrange a pair of the first carriers 21 and 21, and the center of the first carrier 21 and 21 is substantially in the cross section { The second carrier 22 is disposed approximately at the center of the cross section of the exhaust pipe 5, and the first carriers 21 and 21 and the second carrier 22 extend in the axial direction of the exhaust pipe.

The first carriers 21 and 21 are a pair of semicylindrical bodies divided in the radial direction, and the second carrier 22 is a straight cylindrical body having a diameter smaller than that of the first carriers 21 and 21. The first carriers 21 and 21 and the second carriers 22 are made of a thin steel plate. The first carriers 21 and 21 and the second carriers 22 contain precious metals having a catalytic function such as platinum and rhodium on walls having a plurality of holes 21a and 22c, respectively. By application). The exhaust pipe 5 is sized with a space between the first carriers 21 and 21.

In FIG. 6, a support member 23 for supporting one end portion 22a of the second carrier 22 in an axially stretchable direction with respect to the exhaust pipe on the exhaust upstream side (left side of the drawing) in the exhaust pipe 5. Is provided. The support member 23 includes a cushion member 24 for inserting and supporting one end 22a of the second carrier 22, an annular holder 25 for accommodating the cushion member 24, and the holder ( It has the bracket 26 which fixes 25 to the exhaust pipe 5. For this reason, the difference in the amount of expansion and contraction in the axial direction can be absorbed between the exhaust pipe 5 and the second carrier 22 accompanying the thermal expansion.

In addition to supporting the second carrier 22 on the exhaust downstream side (right side of the drawing) in the exhaust pipe 5, a partition plate 27 is provided for the passage membrane between the second carrier 22 and the exhaust pipe 5. . The trimming plate 27, which is made of a thin steel plate (approximately dish-shaped end plate), fixes the flange portion 27a of the trimming plate 27 to the exhaust pipe 5 by plug welding, and the through hole at the center of the cross section is approximately center. The other end 22b of the second carrier 22 is inserted into the 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 is formed by rolling the corrugated plate in a cylindrical shape, fixing the polymerized surface by spot welding, and having a wavy shape in the circumferential direction. For this reason, the cushion member 24 is elastically deformable with respect to the exhaust pipe 5 by elastic deformation, and can absorb the difference of the amount of expansion and contraction between the exhaust pipe 5 and the second carrier 22 accompanying thermal expansion. Can be.

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

Next, the assembly procedure of the 2nd support body 22 of the said structure is demonstrated based on FIG. 6 and FIG. 9A-9E.

First, the cap 28 is fitted to one end 22a of the second carrier 22 in FIG. 9A, and the one end 22a and the cap 28 of the second carrier 22 in FIG. 9B. The peripheral edge of the edge is fixed by spot welding, and one end portion 22a is closed.

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

Thereafter, the holder 25 containing the cushion member 24 (see FIG. 6) is inserted into one end 22a of the second carrier 22 in FIG. 9D, 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 of the half-section as shown in FIG. 6, and the holder 25 in the bracket 26 fixed in advance. The upper and lower half portions of the exhaust pipe 5 are covered, and the upper and lower half parts are welded, and the flange portion 27a of the exhaust pipe 5 and the trimming plate 27 is plugged to complete the assembly work.

Next, the operations of the first exhaust purification apparatus 10 and the second exhaust purification apparatus 20 will be described with reference to FIGS. 2 and 6.

As shown in FIG. 2, the exhaust of the engine flows in from one end portion 5a of the exhaust pipe 5, and when passing through the first exhaust purification apparatus 10, the precious metal held in the inner pipe 11 and The reaction is brought into contact with each other to reach the purified second exhaust purification apparatus 20.

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

The exhaust pipe 5 is larger in diameter than the other portion in which the second exhaust gas purifying device 20 is disposed, and the upstream side is the expansion chamber 29 by blocking the front and rear sides of the trimming plate 27. For this reason, the pulsation of the exhaust gas from the expansion chamber 29 to the engine 3 is regulated to achieve a substantially flat steady flow. Therefore, the exhaust gas flows in the direction of the arrow in FIG. 6, and the exhaust gas flowing near the pipe wall of the exhaust pipe 5 comes into contact with the precious metal supported in the first carriers 21 and 21 to be purified.

In addition, the exhaust gas flows into the second carrier 22 through a plurality of holes 22c bored in the wall of the second carrier 22, and passes through the other end 22b to the exhaust downstream of the exhaust pipe 5. Emitted to the atmosphere. The exhaust gas comes into contact with, reacts with, and purifies the precious metal contained in the second carrier 22 as it passes through the second carrier 22.

In this case, the exhaust gas comes into contact with the catalytic metal contained in the inner and outer surfaces of the second carrier 22 by passing through the plurality of holes 22c bored in the wall of the second carrier 22, so that the exhaust and the catalyst metal The contact area becomes large, and the catalytic metal sufficiently exerts a purifying action.

As described above, in order to sufficiently exhibit the purification action of the catalyst, it is necessary to activate the catalyst at a high temperature. On the other hand, the temperature of the exhaust gas flowing through the exhaust pipe 5 is high at the center of the cross section of the pipe. Since the second carrier 22 passes relatively high temperature exhaust gas flowing through the cross-section central portion of the exhaust pipe 5 in contact with the catalyst metal, the catalyst metal is heated to a high temperature and sufficiently activated, thereby exhibiting a purifying effect sufficiently. Since the second carrier 22 is a porous plate cylinder, the pressure loss when exhaust passes is small, and the influence on the performance of the engine is small.

In this way, the exhaust gas reacts with the noble metals supported in the first carriers 21 and 21 and the second carriers 22, and is purified. In addition, since the exhaust gas becomes approximately smooth steady flow, the purifying capacity of the second exhaust gas purifying apparatus 20 is not changed and the gas is purified efficiently.

The second carrier 22 becomes higher than the exhaust pipe 5 due to reaction heat. In the second carrier 22, the other end 22b of the second carrier 22 is fixed to the exhaust pipe 5 by the trimming plate 27, so that the exhaust pipe 5 and the second carrier 22 with thermal expansion are attached. If a difference in the amount of expansion and contraction occurs between), one end portion 22a is extended in the direction of the white arrow to absorb the difference in the amount of extension. The difference in the amount of extension in the radial direction 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 a case in which the exhaust upstream side is closed. For example, the second carrier 22 may be configured as shown in FIGS. 10A to 10D.

10A to 10D show a modification of the second carrier 22 according to the first embodiment.

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

In FIG. 10B, one end portion 22a of the second carrier 22 is flattened to constitute a cap 32. As shown in FIG.

10C shows a plurality of porous plate braids spirally mounted at one end 22a of the second carrier 22 in order to increase the passage resistance of the exhaust. It is the structure which used the cap 33.

10D is a configuration in which one end portion 22a of the second carrier 22 is closed with a flat plate cap 34. Instead of attaching the plate-shaped porous plate cap 34, one end portion 22a may be configured to form a plate-shaped cap with its periphery bent toward the center of the second carrier 22 to close the exhaust upstream side.

Each cap 31, 32, 33, 34 shown in FIGS. 10A-10D has the same function as that of the first embodiment described above, and furthermore, each cap 31, 32, 33, 34 has a porous plate. The pressure loss becomes smaller than that of the first embodiment.

The supporting structure of the second carrier 22 is that one side of the second carrier 22 is elastically supported in the axial direction with respect to the exhaust pipe 5, and the other is fixed to the exhaust pipe 5. It is good also as a structure shown to 11A-11H degree.

11A to 11H show a modification of the supporting structure of the second carrier 22 according to the first embodiment. The exhaust flows in the direction of the arrow in the figure, and one end portion 22a of the second carrier 22 is extended in the direction of the white arrow by thermal expansion.

The supporting structure of the second carrier 22 shown in FIG. 11A extends one end portion 22A of the second carrier 22 to the exhaust upstream side of the support member 23 and the one end portion 22a is flat. It is made the structure closed by the upper cap 28. The support structure of the 2nd support body 22 shown by FIG. 11B has the structure which closed the exhaust upstream side (left side of the figure) of the support member 23 with the cap 36. As shown in FIG. One end has a portion (22a) and between the cap and 36 is larger than the gap expansion amount due to thermal expansion of the second carrier (22) (S _1). In this case, it is not necessary to attach a cap to one end 22a of the second carrier 22.

In the supporting structure of the second carrier 22 shown in FIG. 11C, the housing 25 of the supporting member 23 is configured to be longer in the axial direction of the exhaust pipe 5 than the bracket 26.

The support structure of the 2nd support body 22 shown in FIG. 11D has the structure of the end support in which the 2nd support body 22 was supported by the trimming plate 27. As shown in FIG. The support member 37 includes a cushion member 38 for elastically supporting the other end 22b of the second carrier 22 in the axial direction of the exhaust pipe 5, and an accommodating portion for accommodating the cushion member 38. And a trimming plate 27 which fixes the housing 39 to the exhaust pipe 5. There is an interval S ₂ between the other end 22b and the flange 39a of the housing 39, and this interval S ₂ is an amount of movement of the other end 22b within the range of the interval S ₂ . And the amount of elongation.

11E is a modification of the structure of FIG. 11D, and the length of the cushion member 38 and the housing 39 is shorter than that of FIG. 11D.

The supporting structure of the second carrier 22 shown in FIG. 11F fixes the one end 22a of the second carrier 22 to the exhaust pipe 5 with the bracket 41 and the second carrier 22 of the second carrier 22. Both ends are supported by the support member 42 so that the other end part 22b can expand and contract 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 the axial direction of the exhaust pipe 5 so as to be extensible, and a housing portion for accommodating the cushion member 43. And a trimming plate 27 for fixing the housing 44 to the exhaust pipe 5. The other end part 22b is extended to the exhaust downstream side (left side of this figure) rather than the support member 42.

The support structure of the second carrier 22 shown in FIG. 11G is a variation of the configuration of FIG. 11F, and the cap 45 with the locking projections which is broken up at one end 22a of the second carrier 22 is attached. The one end part 22a is closed by attaching this.

11H is a configuration of the cushion member 48 in which a stainless wire is incorporated into a ring as a modification of the cushion members 24, 38, 43. As shown in FIG. For example, the support member 46 includes a seat plate 47 wound around the other end 22b of the second carrier 22 and the other end 22b into which the seat plate 47 is inserted, in the axial direction of the exhaust pipe 5. The front and back two cushion members 48 and 48 which are elastically supported by the support member, a cylindrical housing portion 49 for accommodating the cushion members 48 and 48, and the housing 49, and the exhaust pipe 5 It consists of a trimming plate (27) and fixed to.

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

In FIG. 12, the 2nd exhaust gas purification apparatus 50 arrange | positions the 1st support body 51 in the vicinity of the inner wall surface of the exhaust pipe 5, and the center part (exhaust pipe 5) in the cross section of this 1st support body 51 is shown. 2nd carrier 52 is arrange | positioned in the center of the cross-section of (). The first carrier 51 and the second carrier 52 extend in the axial direction of the exhaust pipe 5.

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

The first carrier 51 and the second carrier 52 are composed of a thin steel sheet porous plate. The first carrier 51 and the second carrier 52 are supported by a precious metal having a catalytic function such as platinum and rhodium on a wall having a plurality of balls 51c and 51c, respectively (coating a solution containing the precious metal, etc. Attached).

FIG. 13 shows the second carrier 52 made of flat plate standing upright 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. The exhaust of the engine flows in the direction of the arrow in this figure, the exhaust flowing near the wall flows through a plurality of holes 51c drilled through the wall of the first carrier 51, and the exhaust flowing through the center substantially in cross section is the second carrier. It flows while passing through a plurality of balls 52a drilled in the wall of 52. For this reason, the exhaust gas is reacted with the noble metal supported in the first carrier 51 and the second carrier 52 to be reacted and purified.

In this case, the exhaust gas contacts the catalytic metal contained in the front and back surfaces of the second carrier 52 by passing through the plurality of holes 52a which are drilled in the wall of the second carrier 52, and thus the exhaust and the contact metal. The contact area of 커 becomes large, and the catalytic metal exhibits sufficient purification.

The precious metal contained in the second carrier 52 is brought into contact with a relatively high temperature exhaust gas flowing through the center of the end face of the exhaust pipe 5, so that the precious metal becomes high temperature and is sufficiently activated and exhibits a purifying effect.

Since the second carrier 52 is made of a flat plate extending in the axial direction of the exhaust pipe 5, the pressure loss at the time of passage of the exhaust becomes even smaller than the configuration of the first embodiment described above.

That is, FIG. 14 shows a modification of the second exhaust purification apparatus 50 according to the second embodiment. The first carrier 51 has a broken distal face shape in which a part of the cylindrical body in the radial direction (for example, the lower part of FIG. 14) is cut out.

In Fig. 15, the first carrier 51 is joined to the inner wall of the exhaust pipe 5 by the flange portions 51b and 51b, which are folded back at both edges of the part of the cut end surface. The second carrier 52 penetrates through the cutout portion of the first carrier 51 and contacts the inner wall of the exhaust pipe 5.

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

In FIG. 16A, the exhaust purification apparatus 61 arranges the front and rear two stage purification apparatuses in the exhaust pipe 5, and a regulating valve for adjusting the displacement between the previous purification apparatus and the rear purification apparatus. A butterfly valve 62 is provided. The purification apparatus at the front end is the configuration of the first exhaust purification apparatus 10 shown in FIG. 3 described above, and the purification apparatus at the rear stage is the configuration of the second exhaust purification apparatus 50 shown in FIG. 12 described above. to be.

The exhaust purification apparatus 63 in FIG. 16B has a structure in which the front and rear three stage purification apparatuses are arranged in the exhaust pipe 5. The purifier at the front end is the configuration of the first exhaust purification apparatus 10 shown in FIG. 3, the suspension purifier is the configuration of the second exhaust purification apparatus 50 shown in FIG. The purifying device at the rear stage is a configuration of the lead pipe 64 extending from the other portion 5b of the exhaust pipe 5 into the exhaust pipe 5. The thin-walled steel sheet of the lead-out pipe 64 is formed and supported on the wall having a pore by containing a noble metal having a catalytic function such as platinum and rhodium (attaching a solution containing the noble metal by coating or the like).

The exhaust gas 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 an approximately central portion in the cross section of the exhaust pipe 5. The carrier 66 is a flat plate made of a thin steel plate, and is supported by a precious metal having a catalytic function such as platinum and rhodium on a wall having a large number of balls (attaching a solution containing the precious metal by coating or the like).

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

The exhaust purification apparatus 68 in FIG. 16E has a structure in which the semi-cylindrical carrier 69 which extends in the axial direction of the exhaust pipe 5 and is closed at both ends in the axial direction is disposed. The carrier 69 has a radially open end 69a disposed substantially in the center of the cross section of the exhaust pipe 5. The carrier 69 is made of a thin steel plate, and supports a precious metal having a catalytic function such as platinum and rhodium on a wall having a large number of balls (attaching a solution containing the precious metal by coating or the like).

The carriers 66 and 69 shown in Figs. 16C, 16D and 16E may be applied to a multistage purification device disposed in the exhaust pipe 5 shown in Figs. 16A and 16B.

In the first, second, and third embodiments and modifications, the thin steel plate carrying the catalyst metal is disposed at approximately the center of the cross section of the exhaust pipe 5 or approximately at the center of the cross section of the first carriers 21, 51. As a specific example, in the first embodiment shown in Figs. 1 to 9 and the modification shown in Figs. 10 and 11, the second carrier 22 made of the porous plate cylinder is constituted. In the second embodiment shown in Figs. 14, 15 and 15, and the third embodiment shown in Figs. 16A and 16B, a second carrier 52 made of a porous plate is formed. In the third embodiment shown in Figs. 16D and 16E, a porous plate, corrugated plate, or semi-normal carriers 66 and 69 are constituted.

Thus, in the present invention, the thin steel sheet is not limited to the constitutions of the above-described embodiments and its modifications, and is not limited to the porous sheet, and the ball shape of the porous sheet, the size and the number of the balls can be arbitrarily selected.

As described above, the exhaust gas purifying apparatus of the internal combustion engine according to the present invention is disposed on the center of the cross section of the exhaust pipe extended from the exhaust port of the internal combustion engine by placing a thin steel plate supported with the catalyst metal on the center of the cross section where the exhaust temperature is high. Because of this arrangement, the catalytic metal can be activated to sufficiently exert the purification effect of the exhaust gas, which can be realized at low cost.

In addition, the exhaust gas purifying apparatus of the internal combustion engine of the present invention has the advantage that the thin steel sheet is a cylindrical body extending in the axial direction of the exhaust pipe so that pressure loss is reduced when the exhaust gas is passed, and therefore, it does not affect the performance of the internal combustion engine. .

Moreover, the exhaust gas purifying apparatus of the internal combustion engine of the present invention constitutes the cylinder by a porous plate, and the exhaust passes through a plurality of holes drilled in the wall of the cylinder by closing the exhaust upstream side of the cylinder, so that the exhaust is front and rear of the second carrier. In contact with the supported catalytic metal. Therefore, the contact area between the exhaust gas and the catalyst 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 extends in the axial direction of the exhaust pipe in the center of the exhaust pipe extending from the exhaust port of the internal combustion engine and extends in the axial direction of the exhaust pipe between the thin steel tube and the exhaust pipe supported by the catalyst metal. By providing the trimming plate closing the passage, the catalyst metal is disposed at a substantially central portion on the cross section where the exhaust temperature is high, thereby activating the catalyst metal to sufficiently exert a purifying action, and at the same time reducing the cost. In addition, the pulsation of the exhaust gas from the internal combustion engine is regulated to be approximately flat normal flow by blocking the front and rear of the trimming plate so that the purifying capacity of the exhaust purification apparatus is not changed, and the purifying action can be sufficiently exhibited. In addition, by supporting the thin steel plate cylinder with a trimming plate that regulates the pulsation of the exhaust, a separate supporting member is not required and the supporting structure is simple.

In addition, the exhaust purification apparatus of the internal combustion engine of the present invention makes it easy to absorb the difference in the amount of extension between the other cylinder and the exhaust pipe due to thermal expansion by attaching the thin steel sheet cylinder to the exhaust pipe in the axial direction.

Moreover, the exhaust purification apparatus of the internal combustion engine of the present invention arranges the first carrier supporting the catalyst metal in the vicinity of the inner wall surface of the exhaust pipe extended from the exhaust port of the internal combustion engine, and the catalyst is disposed approximately in the center on the cross section of the first carrier. By arranging the second carrier supporting the metal, the carrier supporting the catalytic metal is disposed on both the inner wall surface of the exhaust pipe and at approximately the center of the cross-section so that the exhaust purification is performed without adversely affecting the performance of the internal combustion engine. It is possible to further increase the cost and to reduce the cost.

Claims (6)

An exhaust purification apparatus comprising an internal combustion engine 3 and an exhaust pipe 5 extending from an exhaust port 4 of the internal combustion engine 3 to purify exhaust gas from the internal combustion engine 3, A thin steel plate cylindrical body 22, which extends in the axial direction of the exhaust pipe 5 and supports catalyst metal, is disposed in a central portion of the exhaust pipe 5 substantially in the cross section, and the thin steel plate cylinder in the exhaust pipe 5 ( 22) and a trimming plate (27) for blocking a passage between the thin steel plate cylinder (22) and the exhaust pipe (5). The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein said thin steel plate (22) is mounted in an axial direction with respect to said exhaust pipe (5). An exhaust purification apparatus comprising an internal combustion engine 3 and an exhaust pipe 5 extending from an exhaust port 4 of the internal combustion engine 3 to purify exhaust gas from the internal combustion engine 3, The first carriers 21 and 51 which are supported and contained the catalyst metal in front of the inner wall surface of the exhaust pipe 5 are arranged, and the catalyst metals are supported by the central portion of the cross section of the first carriers 21 and 51. The second carriers 22 and 52 are disposed, and the first carriers 21 and 51 and the second carriers 22 and 52 are coaxially disposed at substantially the center of the large diameter portion of the exhaust pipe 5. Exhaust purifier of an internal combustion engine, characterized in that. 4. The exhaust gas purifying apparatus for an internal combustion engine according to claim 3, wherein said second carrier (22) is made of a cylinder, and said cylinder is made of a porous plate, and the exhaust upstream side is closed. 4. The exhaust gas purifying apparatus for an internal combustion engine according to claim 3, wherein said first carrier (51) is a cylindrical body and said second carrier (52) is a flat plate. The exhaust purification apparatus of an internal combustion engine according to claim 3, wherein the first carrier (21, 51) and the second carrier (22, 52) have a plurality of holes (21a, 51c, 22c, 52a). .