WO1996037691A1

WO1996037691A1 - Exhaust emission control device for internal combustion engines

Info

Publication number: WO1996037691A1
Application number: PCT/JP1996/001382
Authority: WO
Inventors: Yoshiyasu Uchida; Nobuhiko Itou; Hiroshi Inokawa; Kenjiro Saito; Nobuhiro Shimada
Original assignee: Honda Giken Kogyo Kabushiki Kaisha
Priority date: 1995-05-25
Filing date: 1996-05-24
Publication date: 1996-11-28
Also published as: TW371013U; JP3614206B2; CN1080370C; CN1184523A; KR100401948B1; JPH08319824A; EP0831211A1; EP0831211B1; EP0831211A4; KR19980702977A

Abstract

An exhaust emission control device wherein a thin steel plate (22) carrying catalytic metals is disposed substantially at the central portion of a cross section of an exhaust pipe (5) extending from an exhaust port (4) of an engine (3). Specifically, since the catalytic metals are disposed substantially at the central portion of the cross section of the exhaust pipe (5) which has a high exhaust gas temperature, an exhaust gas controlling action is sufficiently performed and moreover the production cost of the device can be reduced.

Description

Specification. Exhaust gas purification equipment for internal combustion engines.

The present invention relates to an improvement in an internal combustion engine, that is, an exhaust gas purification device for purifying exhaust gas discharged from the engine. Background art

Conventionally, as an exhaust purification device for an internal combustion engine, for example, an “exhaust gas purification device for an internal combustion engine” disclosed in Japanese Patent Application Laid-Open No. 3-85316 and Japanese Patent Application Laid-Open No. 2. Description of the Related Art An "exhaust gas purifying apparatus for a motorcycle or the like" disclosed in Japanese Patent Application Laid-Open No. 7-221 is known.

According to FIG. 17 and FIG. 18, the “exhaust gas purifying apparatus for an internal combustion engine” disclosed in Japanese Patent Application Laid-Open No. 3-855316 describes the exhaust gas of a small internal combustion engine mounted on a motorcycle or the like. The exhaust pipe 100 is connected to the mouth, and a perforated plate inner pipe 101 extending in the same direction as the exhaust pipe 100 is arranged along the inner wall of the exhaust pipe 100. The carrier 102 containing the catalyst is attached to the wall of the substrate.

According to FIG. 19, FIG. 20 and FIG. 21, the “exhaust gas purifying apparatus for a motorcycle or the like” disclosed in Japanese Patent Application Laid-Open No. 4-1287872 is mounted on a motorcycle or the like. An exhaust muffler 110 is connected to the exhaust port of a small internal combustion engine, and a catalyst tube 111 is disposed at the center of the cross section of this exhaust muffler (corresponding to an exhaust pipe) 110. It contains the catalyst 1 1 2. Catalyst 1 1 2 is a catalyst element with a catalytic structure attached to a honeycomb structured catalytic element _c

Generally, it is necessary to activate the catalyst at a high temperature in order to sufficiently exert the purifying action of the catalyst. However, it is not easy to raise the exhaust gas temperature to activate the catalyst in a small internal combustion engine: therefore, consideration must be given to raising the temperature of the catalyst as much as possible. To this end, the temperature of the exhaust gas flowing through the exhaust pipe is high at the center of the cross section of the pipe, and relatively low near the pipe wall. However, the “exhaust gas purifying apparatus for an internal combustion engine” shown in FIGS. 17 and 18 has an inner pipe 101 with a catalyst arranged along the inner wall of the exhaust pipe 100, It is not easy to fully demonstrate the effect of gasification-The "exhaust gas purifier for motorcycles and the like" shown in Figs. 19 to 21 is equipped with a catalyst 11 in the center of the cross section of the exhaust muffler 110 2 and the exhaust gas temperature is relatively high, so that it is easy to exhibit purification action. However, the catalyst body 112 consisting of a catalyst element having a honeycomb structure is shown in FIGS. 17 and 18 above. The pressure loss is larger than that of the perforated inner tube 101. Since the flow velocity of the exhaust gas flowing through the exhaust muffler 110 increases at the center of the cross section of the pipe, the pressure loss further increases. For this reason, the pressure loss has a significant effect on the performance of the internal combustion engine, and is a factor that cannot be ignored especially in low-power internal combustion engines such as motorcycles. Further, in the configuration in which the catalyst body 112 composed of the catalyst element having the honeycomb structure is housed in the catalyst tube 111, the inner tube 101 is exhausted as shown in FIGS. 17 and 18 described above. Significantly higher cost than configuration arranged in 100-Disclosure of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide (1) an exhaust purification device for an internal combustion engine which (1) exerts a sufficient purifying action, (2) minimizes the performance of the internal combustion engine, and (3) has a low cost. It is in.

According to the present invention, a thin steel plate supporting a catalyst metal is arranged at a substantially central portion of an exhaust pipe extending from an exhaust port of an internal combustion engine. Therefore, the catalyst metal is arranged at the approximate center of the cross section of the exhaust pipe where the exhaust temperature is high, and the catalyst metal is activated and the exhaust gas purifying action is sufficiently exhibited.

As the thin steel plate, a cylindrical body extending in the axial direction of the exhaust pipe is preferable because pressure loss when exhaust gas passes is reduced.

It is preferable that the cylindrical body is constituted by a perforated plate, and the upstream side of the exhaust of the cylindrical body be closed.- That is, since the exhaust passes through a number of holes formed in the wall of the cylindrical body, the exhaust is The catalyst comes into contact with the catalyst metal supported on the front and back surfaces of the second carrier.- Therefore, the contact area between the exhaust gas and the catalyst metal is increased, and the action of purifying the exhaust gas is enhanced. Exhaust gas is exhausted almost at the center of the cross section of the exhaust pipe extending from the exhaust port of the engine. A thin steel plate cylinder extending in the axial direction of the tube and carrying a catalyst metal is disposed, and the thin steel tube is supported in the exhaust pipe, and a passage between the thin steel tube and the exhaust pipe is provided. A partition plate was provided to close the. That is, the partition plate partitions the front and rear thereof to regulate the pulsation of the exhaust gas from the internal combustion engine, so that a substantially smooth steady flow is obtained. For this reason, the purification performance of the exhaust gas purification device is enhanced because the purification ability does not fluctuate. In addition, since the thin steel plate cylinder is supported by the partition plate that regulates the pulsation of exhaust gas, a separate support member is not required.

The thin-walled steel tube is attached to the exhaust pipe so as to be able to expand and contract in the axial direction, so that the difference in the amount of expansion between the thin-walled steel tube and the exhaust pipe due to thermal expansion is increased. Is absorbed, which is preferable.

Further, in the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, a first carrier carrying a catalyst metal is disposed along a vicinity of an inner wall surface of an exhaust pipe extending from an exhaust port of the internal combustion engine, The second support carrying the catalyst metal was arranged substantially at the center of the cross section. That is, since the carrier carrying the catalyst metal is disposed both near the inner wall surface of the exhaust pipe and substantially at the center of the cross section, the performance of the internal combustion engine is not adversely affected, and the purification action of the exhaust gas is reduced. Even higher. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of a motorcycle equipped with an internal combustion engine exhaust gas purification apparatus 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,

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

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

FIG. 5 is a perspective view showing a first embodiment of the second exhaust gas purification apparatus according to the present invention,

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

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

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

FIGS. 9A to 9E are assembly explanatory views showing a first embodiment of the second carrier according to the present invention, and FIGS. 10 to 10D are diagrams for the first embodiment of the second carrier according to the present invention. Modification Diagram,

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

FIG. 12 is a perspective view of a second exhaust gas purification device according to the second embodiment,

FIG. 13 is a sectional view taken along line FF in FIG. 12,

FIG. 14 is a diagram showing a modification of the second exhaust gas purification device according to the second embodiment,

FIG. 15 is a sectional view taken along line GG in FIG.

FIGS. 16A to 16E are schematic diagrams of an exhaust gas purification device according to the third embodiment,

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

Fig. 18 is a partial longitudinal side view of a conventional exhaust pipe,

Figure 19 is a plan view of a conventional exhaust muffler,

FIG. 20 is a partial cross-sectional perspective view of a conventional exhaust gas purification device,

FIG. 21 is a longitudinal sectional view showing a conventional structure near a catalyst tube. BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment will be described with reference to FIGS.

In FIG. 1, a motorcycle 1 includes a two-cycle engine (internal combustion engine) 3 near the center of a vehicle body 2, connects an exhaust pipe 5 to an exhaust port 4 of the engine 3, and silences a rear portion of the exhaust device 5. Connect the container 6.

FIG. 2 shows an exhaust pipe 5 according to the present invention. The exhaust pipe 5 is made of a thin steel plate and formed in a circular cross section. One end 5a is connected to the exhaust port 4 (see FIG. 1) of the engine 3 by a flange, and the other end 5b is silenced. A vessel 6 (see FIG. 1) is connected by a flange, and a first exhaust gas purification device 10 upstream of the exhaust gas and a second exhaust gas purification device 20 downstream of the exhaust gas are arranged therein. The first exhaust gas purification device 10 is a purification device of the preceding stage, and the second exhaust gas purification device 20 is a purification device of the subsequent stage. The portion of the exhaust pipe 5 where the second exhaust gas purification device 20 on the exhaust downstream side is arranged has a larger diameter than the other portions:

FIG. 3 shows a cross-sectional structure of the first exhaust gas purification device 10.

The first exhaust gas purification device 10 is composed of an inner pipe 11 1 arranged in the exhaust pipe 5- The inner pipe 11 is a cylindrical body extending in the same direction as the exhaust pipe 5 along the inner wall of the exhaust pipe 5, and is formed of a thin plate made of a thin steel plate. The inner pipe 11 has one end 11 a of the inner pipe 11 fixed to the exhaust pipe 5 by reversal, and the other end 11 b is capable of extending and contracting in the axial direction with respect to the exhaust pipe 5. Supported by 13 For this reason, the difference in the amount of axial elongation between the exhaust pipe 5 and the inner pipe 11 due to thermal expansion can be absorbed.

The inner tube 11 has a catalyst having a noble metal such as platinum or rhodium supported on a wall surface having porosity 11 c (a solution containing a noble metal is attached by coating or the like). The intermediate portion has a size having a gap 5c between itself and the inner tube 11.

In FIG. 4, the exhaust pipe 5 has a half-cylindrical shape divided in the radial direction, and is integrated by welding with the inner pipe 11 incorporated therein.

The support member 13 is formed by winding a corrugated plate (corrugated plate) into a cylindrical shape, and fixing the overlapping surface by spot welding, and has a circumferentially corrugated shape. Therefore, 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 a difference in elongation between the exhaust pipe 5 and the inner pipe 11 due to thermal expansion. The support member 13 is not limited to the above-described configuration including the corrugated plate, and may be, for example, a stainless steel wire braided to form a ring.

Reference numerals 14 and 14 denote a pair of protectors divided in the radial direction to cover the exhaust pipe 5 which becomes hot. These protectors 14 and 14 are bolted to a plurality of nuts 15 welded to the outer peripheral surface of the exhaust pipe 5.

FIG. 5 shows a second exhaust gas purification apparatus 20 according to the present invention. The second exhaust gas purifying apparatus 20 has a pair of first carriers 21 and 21 arranged along the vicinity of the inner wall surface of the exhaust pipe 5, and a substantially central section of the first carriers 21 and 21. The second carrier 22 is disposed in a portion (approximately the center of the cross section of the exhaust pipe 5), and the first carriers 21, 21 and the second carrier 22 extend in the axial direction of the exhaust pipe 5.

The first carriers 21 and 21 are composed of a pair of semi-cylindrical members divided in the radial direction, and the second carriers 22 are composed of straight cylindrical members having a smaller diameter than the first carriers 21 and 21. . The first carriers 21 and 21 and the second carrier 22 are formed of a thin plate made of a thin steel plate. The first carrier 21, 21, and the second carrier 22 each have a noble metal having a catalytic function such as platinum or rhodium supported on a wall surface having a large number of holes (21 a, 22 c). (Including precious metals The solution is attached by coating or the like): The exhaust pipe 5 has a size having a gap between the first carrier 21 and the first carrier 21.

In FIG. 6, a support for supporting the one end 22 a of the second carrier 22 so as to be able to expand and contract in the axial direction with respect to the exhaust pipe 5 is provided on the exhaust upstream side (left side in the figure) in the exhaust pipe 5. A member 23 is provided. The support member 23 includes a cushion member 24 for inserting and supporting one end 22 a of the second carrier 22, an annular receiving portion 25 for storing the cushion member 24, and the receiving portion. A bracket 26 for fixing the exhaust pipe 5 to the exhaust pipe 5 _; for this reason, a difference in the amount of axial elongation between the exhaust pipe 5 and the second carrier 22 due to thermal expansion is absorbed. it can.

A partition plate for supporting the second carrier 22 and closing the passage between the second carrier 22 and the exhaust pipe 5 is provided on the exhaust downstream side (the right side in this figure) in the exhaust pipe 5. 27 are provided. The partition plate 27 made of a thin steel plate end plate (substantially dish-shaped end plate) has a flange 27 a of the partition plate 27 fixed to the exhaust pipe 5 by plug welding. The other end 22 b of the second carrier 22 is inserted into the through hole 27 b and fixed by welding. One end (upstream exhaust side) 22 a of the second carrier 22 is closed by a cap 28.

In FIG. 7, the cushion member 24 is formed by winding a corrugated plate (corrugated plate) into a cylindrical shape and fixing the overlapping surface by spot welding, and has a wavy shape in the circumferential direction. For this reason, the cushion member 24 can expand and contract radially with respect to the exhaust pipe 5 due to elastic deformation, and absorbs a difference in the amount of expansion between the exhaust pipe 5 and the second carrier 22 due to thermal expansion. can do.

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

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

First, a cap 28 is fitted to one end 22 a of the second carrier 22 in FIG. 9A, and one end 22 a of the second carrier 22 and the edge of the cap 28 are connected in FIG. 9B. Fix by spot welding and close one end 22a.

Next, in FIG.9C, the other end 22b of the second carrier 22 is inserted into the through hole 27b of the partition plate 27. Insert and fix by welding.

After that, in FIG. 9D, the receiving portion 25 containing the cushion member 24 (see FIG. 6) is inserted into one end 22a of the second carrier 22, and assembled as shown in FIG. 9E.

Finally, the second carrier 22 shown in FIG. 9E is positioned in the lower half of the exhaust pipe 5 in a half shape as shown in FIG. 6, and the receiving part 25 is mounted on the bracket 26 fixed in advance. And the upper and lower halves of the exhaust pipe 5 are covered with each other, and the exhaust pipe 5 and the flange 27 a of the partition plate 27 are plug-welded to complete the assembly work.

Next, the operation of the first exhaust gas purification device 10 and the second exhaust gas purification device 20 will be described with reference to FIGS.

As shown in FIG. 2, the exhaust gas of the engine flows in from one end 5 a side of the exhaust pipe 5 and passes through the first exhaust gas purification device 10, and the noble metal carried on the inner pipe 11 And reacts therewith and is purified and reaches the second exhaust gas purification device 20.

As shown in FIG. 6, in the second exhaust gas purification device 20, exhaust gas flows from the left side of the figure. However, since the one end 22 a of the second carrier 22 is closed by the cap 28, the exhaust does not flow in from the one end 22 a.

The portion of the exhaust pipe 5 where the second exhaust gas purification device 20 is disposed has a larger diameter than the other portions, and the front and rear sides of the exhaust pipe 5 are partitioned by a partition plate 27 to form an expansion chamber 29 on the exhaust upstream side. . For this reason, the pulsation of the exhaust gas from the engine 3 is regulated in the expansion chamber 29 to provide a generally smooth 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 noble metal carried on the first carriers 21 and 21 to react and be purified.

Further, the exhaust gas passes through a number of holes 22 c formed in the wall of the second carrier 22, enters the second carrier 22, passes through the other end 22 b, and is exhausted downstream of the exhaust pipe 5. Released to the atmosphere from the side. When the exhaust gas passes through the second carrier 22, the exhaust gas contacts and reacts with the noble metal supported on the second carrier 22, and is purified.

In this case, the exhaust gas passes through a large number of holes 22 c formed in the wall of the second support 22, and comes into contact with the catalyst metal supported on the front and back surfaces of the second support 22. The contact area with the catalyst metal is large, and the catalyst metal exerts a sufficient purifying action.

As described above, in order for the catalyst to fully exhibit its purifying action, the catalyst must be heated to a high temperature. Need to be activated. 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 allows relatively high-temperature exhaust gas flowing through the central part of the cross section of the exhaust pipe 5 to pass therethrough in contact with the catalyst metal, the catalyst becomes high in temperature and is sufficiently activated to sufficiently purify the purifying action. Demonstrate. Since the second carrier 22 is made of a perforated plate cylinder, the pressure loss when exhaust gas passes through is small, and the effect on the engine performance is small:

As described above, the exhaust gas comes into contact with and reacts with the noble metal supported on the first carriers 21 and 21 and the second carrier 22 and is purified, so that the exhaust gas is efficiently purified. Further, since the exhaust gas has a substantially steady flow, the purification performance of the second exhaust gas purification device 20 does not fluctuate and the exhaust gas is efficiently purified.

The temperature of the second carrier 22 becomes higher than that of the exhaust pipe 5 due to reaction heat or the like. Since the second carrier 22 has the other end 2 2 b of the second carrier 22 fixed to the exhaust pipe 5 by the partition plate 27, the exhaust pipe 5 and the second carrier 22 are connected with the thermal expansion. When a difference in the amount of elongation occurs between the two, the end 22a extends in the direction of the outline arrow to absorb the difference in the amount of elongation. The difference in the radial elongation 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 has a closed exhaust upstream side, and may have, for example, the configuration shown in FIGS. 10A to 1OD:

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

FIG. 10A shows a configuration in which one end 22 a of the second carrier 22 is closed by a perforated plate cap 31 bulging to the exhaust upstream side, and the perforated plate cap 31 is press-molded. It was formed.

FIG. 10B shows a configuration in which one end 22 a of the second carrier 22 is flattened to form a cap 32.

FIG. 10C shows that a plurality of perforated plate blades are attached to one end 22 a of the second carrier 22 in a spiral shape (windmill shape) in order to increase the exhaust gas passage resistance. The perforated plate blade is configured as a cap 33-FIG. 10D shows one end 22 a of the second carrier 22 as a flat plate-shaped perforated plate cap 3 4 It is a configuration closed by. Instead of attaching a plate-shaped cap 34 made of a perforated plate, one end 22 a itself is bent toward the center of the second carrier 22 to form a plate-shaped cap so as to close the exhaust upstream side. Each of the caps 31, 32, 33, and 34 shown in FIGS. 1OA to 10D has the same operation as that of the first embodiment described above. Since it is made of a perforated plate, the pressure loss due to the provision of the caps 31, 32, 33, 34 can be smaller than that of the first embodiment.

The support structure of the second carrier 22 is such that one of the second carriers 22 is supported so as to be able to expand and contract in the axial direction with respect to the exhaust pipe 5 and the other is fixed to the exhaust pipe 5. 1 A to Fig. 11 H

11 to 11H show modified examples of the support structure of the second carrier 22 according to the first embodiment. The exhaust gas flows in the directions of the arrows in these figures, and the one end 22 a of the second carrier 22 extends in the direction of the white arrow due to thermal expansion.

In the support structure of the second carrier 22 shown in FIG. 11A, one end 22 a of the second carrier 22 extends to the exhaust upstream side of the support member 23, and the one end 22 a It is configured to be closed by a flat cap 28.

The support structure of the second carrier 22 shown in FIG. 11B has a configuration in which the exhaust upstream side (the left side in this figure) of the support member 23 is closed by the cap 36. There is a gap between the one end 22 a and the cap 36 that is larger than the amount of expansion of the second carrier 22 due to thermal expansion. In this case, it is not necessary to attach a cap to one end 22a of the second carrier 22:

The support structure of the second carrier 22 shown in FIG. 11C has a configuration in which the receiving portion 25 of the support member 23 is longer in the axial direction of the exhaust pipe 5 than the bracket 26- The support structure of the second carrier 22 shown in FIG. 11D has a configuration of one end support in which the second carrier 22 is supported only by the partition plate 27. The support member 37 includes a cushion member 38 that supports the other end 22 b of the second carrier 22 so as to be able to expand and contract in the axial direction of the exhaust pipe 5, and a receiving part 39 that accommodates the cushion member 38. And a partition plate 27 for fixing the receiving portion 39 to the exhaust pipe 5. A gap S ₂ is provided between the flange 3 9 a of the other end 2 2 b and the receiving portion 3 9, the clearance S ₂ is the other end in the range of the clearance S ₂ It regulates the amount of movement and elongation of part 22b.

FIG. 11E is a modification of the configuration of FIG. 11D, in which the lengths of the cushion member 38 and the receiving portion 39 are shorter than the configuration of FIG. 11D—shown in FIG. 11F. The support structure of the second carrier 22 is such that one end 22 a of the second carrier 22 is fixed to the exhaust pipe 5 with a bracket 41, and the other end 22 b of the second carrier 22 is connected to the exhaust pipe 5. Both ends are supported by a support member 42 so as to be able to expand and contract in the axial direction. The support member 42 includes a cushion member 43 that supports the other end 22 b of the second carrier 22 so as to be able to expand and contract in the axial direction of the exhaust pipe 5, and a receiving part 44 that stores the cushion member 43. And a partition plate 27 for fixing the receiving portion 44 to the exhaust pipe 5. The other end 22 b extends downstream of the support member 42 on the exhaust side (left side in this figure). The support structure of the second carrier 22 shown in FIG. 11G is a modified example of the configuration of FIG. 11F, and the cap with cut-and-raised claw 4 5 is provided at one end 22 a of the second carrier 22. By attaching a, the end 22a is closed.

FIG. 11H is a modified example of the above cushion members 24, 38, and 43, and has a configuration of a cushion member 48 in which a stainless wire is woven into a ring shape. For example, the support member 46 includes a seat plate 47 wound around the other end 22 b of the second carrier 22, and the seat plate 47 is inserted into the support member 46, and the other end 22 b is inserted in the axial direction of the exhaust pipe 5. Two cushion members 48, 48, which can be extended and retracted, and a cylindrical receiving part 49 for accommodating the cushion members 48, 48, and the receiving part 49 fixed to the exhaust pipe 5. Next, a second embodiment of the second exhaust gas purification device will be described with reference to FIGS. 12 and 13. In FIG. 12, the second exhaust gas purification device 50 A first carrier 51 is arranged along the inner wall surface of the exhaust pipe 5, and a second carrier 5 is provided at substantially the center of the cross section of the first carrier 51 (substantially at the center of the cross section of the exhaust pipe 5). 2 are arranged. 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 includes cone portions 51 a and 51 a at both ends in the axial direction. One or both of the cone portions 51 a and 51 a is connected to the exhaust pipe 5. It is fixed by welding. The second carrier 52 is formed of a flat plate, and one or both ends in the longitudinal direction are fixed to the first carrier 51 by welding.

The first carrier 51 and the second carrier 52 are formed of a thin steel plate perforated plate. The carrier 51 and the second carrier 52 carry a noble metal having a catalytic function such as platinum or rhodium on a wall surface having a large number of holes 51 c and 52 a, respectively. (Attach by coating etc.)

FIG. 13 shows a state where the second carrier 52 made of a flat plate stands in the first carrier 51. '

Next, the operation of the second exhaust gas purification device 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, and the exhaust flowing near the pipe wall flows while passing through a number of holes 51 c formed in the wall of the first carrier 51, and passes through a substantially central portion in cross section. The flowing exhaust gas flows while passing through a large number of holes 52 a formed in the wall of the second carrier 52. Therefore, the exhaust gas comes into contact with the noble metal supported on the first carrier 51 and the second carrier 52 to react and be purified.

In this case, the exhaust gas passes through a large number of holes 52 a formed in the wall of the second carrier 52, and comes into contact with the catalyst metal supported on the front and back surfaces of the second carrier 52. The contact area with the catalyst metal is large, and the catalyst metal exerts a sufficient purifying action.

The noble metal carried on the second carrier 52 comes into contact with the relatively high-temperature exhaust gas flowing through the central portion of the cross section of the exhaust pipe 5, so that it becomes high in temperature and is sufficiently activated to sufficiently exert a purifying action.

Since the second carrier 52 is formed of a flat plate extending in the axial direction of the exhaust pipe 5, the pressure loss when exhaust gas passes is further reduced as compared with the configuration of the above-described first embodiment. The second exhaust gas purification device 50 having the example configuration may have the configuration shown in FIGS. 14 and 15, for example.

That is, FIG. 14 shows a modification of the second exhaust gas purification device 50 according to the second embodiment. The first carrier 51 has a partially circular cross-sectional shape in which a part of the cylindrical body in the radial direction (for example, the lower part in FIG. 14) is cut out.

In FIG. 15, the first carrier 51 contacts the inner wall of the exhaust pipe 5 with the flange portions 51 b and 51 b folded from both edges of the cross section of the broken circle. The second carrier 52 penetrates through the missing circle of the first carrier 51 and is in contact with the inner wall of the exhaust pipe 5.

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

The exhaust gas purification device 61 in Fig. 16A is a control valve that has two stages of purification devices, one in front and the other in the exhaust pipe 5, and adjusts the amount of exhaust gas between the upstream purification device and the downstream purification device. (For example, butterfly valve) It has a configuration with 62 interposed. The former purification device has the structure of the first exhaust gas purification device 10 shown in FIG. 3 described above, and the latter purification device has the second exhaust gas purification device shown in FIG. 12 described above. This is the configuration of the device 50.

The exhaust gas purifier 63 shown in FIG. 16B has a configuration in which three stages of purifiers are arranged in the exhaust pipe 5 before and after. The purification device in the first stage has the configuration of the first exhaust gas purification device 10 shown in FIG. 3 described above, and the purification device in the middle stage is the second exhaust gas purification device 5 shown in FIG. The purifying device at the subsequent stage has a configuration of an outlet pipe 64 extending into the exhaust pipe 5 from the other end 5 b of the exhaust pipe 5. The outlet pipe 64 is composed of a perforated plate made of a thin steel plate, and carries a noble metal having a catalytic function such as platinum or rhodium on a porous wall (adhesion of a solution containing a noble metal by application or the like). ):

The exhaust gas purifying device 65 in FIG. 16C has a configuration in which a carrier 66 extending in the axial direction of the exhaust pipe 5 is arranged at a substantially central portion of the cross section of the exhaust pipe 5. The carrier 66 is a flat plate made of a thin steel plate perforated plate, and has a noble metal having a catalytic function such as platinum or rhodium supported on a wall surface having a large number of holes (a solution containing a noble metal is used). The exhaust gas purifying device 67 shown in Fig. 16D is a modification of the exhaust gas purifying device shown in Fig. 16C above. The carrier 66 is replaced with a corrugated plate instead of a flat plate. Board).

The exhaust gas purification device 68 in FIG. 16E has a configuration in which a semi-cylindrical carrier 69 extending in the axial direction of the exhaust pipe 5 and having both axial ends closed is disposed. The carrier 69 has a radially open end 69 a disposed substantially at the center of the cross section of the exhaust pipe 5. The carrier 69 is made of a thin steel plate perforated plate, and carries a noble metal having a catalytic function such as platinum or rhodium on a wall surface having a large number of holes (a solution containing a noble metal is applied by coating or the like).

The supports 66 and 69 shown in FIGS. 16C, 16D and 16E are arranged in a multi-staged exhaust pipe 5 shown in FIGS. 16A and 16B. May be applied to purification equipment: In the first, second, and third embodiments and the modified examples, the “thin steel plate” supporting the catalyst metal is provided at substantially the center of the cross section of the exhaust pipe 5 or substantially 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 modified examples shown in FIGS. 10 and 11, the second carrier 2 made of a perforated plate cylindrical body is used. The second embodiment shown in FIGS. 12 and 13 and the modified examples shown in FIGS. 14 and 15 and the third embodiment shown in FIGS. A second carrier 52 composed of a flat plate made of a plate is constituted, and in the third embodiment shown in FIGS. 16C, 16D and 16E, the second carrier 52 is formed of a perforated flat plate, a corrugated plate, or a half-cylinder Carriers 66 and 69 are constituted. As described above, in the present invention, the “thin-walled steel sheet” is not limited to the configuration of each of the above-described embodiments and the modifications thereof, and is not limited to a perforated plate. The shape and size of the holes are arbitrary. Industrial applicability

As described above, the exhaust gas purifying apparatus for an internal combustion engine according to the present invention has a low exhaust gas temperature by arranging a thin steel plate carrying a catalytic metal at a substantially central portion of a cross section of an exhaust pipe extending from an exhaust port of the internal combustion engine. Since the catalyst metal is arranged approximately at the center of the high cross section, the catalyst metal can be activated to sufficiently exhibit the exhaust gas purifying action, and can be realized at low cost.

In the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, the thin steel plate is formed into a cylindrical body extending in the axial direction of the exhaust pipe, so that pressure loss when exhaust gas passes through is reduced. Has the advantage of not affecting performance =

Further, in the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, since the cylindrical body is formed of a perforated plate, and the exhaust upstream side of the cylindrical body is closed, exhaust gas passes through a number of holes formed in the wall of the cylindrical body. Therefore, the exhaust gas comes into contact with the catalyst metal supported on the front and back surfaces of the second carrier. Therefore, the contact area between the exhaust gas and the catalytic metal is increased, and the exhaust gas purifying action is further enhanced.

Still further, the exhaust gas purifying apparatus for an internal combustion engine according to the present invention comprises a thin steel plate supporting a catalytic metal extending in the axial direction of the exhaust pipe substantially at the center of the cross section of the exhaust pipe extending from the exhaust port of the internal combustion engine. A high exhaust temperature is achieved by disposing a cylindrical body, supporting a thin-walled steel plate in the exhaust pipe, and providing a partition plate that closes the passage between the thin-walled steel cylinder and the exhaust pipe. Since the catalytic metal is arranged at the center of each part, the catalytic metal can be activated to exert its purifying action sufficiently and to reduce costs. Since the pulsation of exhaust gas from the exhaust gas is regulated to make a substantially smooth steady flow, the purification ability of the exhaust gas purification device does not fluctuate, and the purification action can be sufficiently exerted. Furthermore, since the thin steel plate cylinder is supported by the partition plate that regulates the pulsation of exhaust gas, a separate support member is not required, and the support configuration is simplified.

Further, in the exhaust gas purifying apparatus for an internal combustion engine of the present invention, since the thin-walled steel plate cylinder is attached to the exhaust pipe so as to be able to expand and contract in the axial direction, the extension between the cylinder and the exhaust pipe due to thermal expansion is provided. It is easy to absorb the difference in the amount.

Still further, the exhaust gas purifying apparatus for an internal combustion engine according to the present invention includes a first carrier carrying a catalyst metal disposed along the vicinity of an inner wall surface of an exhaust pipe extending from an exhaust port of the internal combustion engine. By arranging the second carrier carrying the catalyst metal at approximately the center of the cross section, the carrier carrying the catalyst metal is disposed both near the inner wall surface of the exhaust pipe and substantially at the center of the cross section, thus improving the performance of the internal combustion engine. There is an advantage that the exhaust gas purifying action can be further enhanced without affecting as much as possible, and the cost can be reduced.

Claims

The scope of the claims

1. An internal combustion engine (3), comprising: an exhaust pipe (5) extending from an exhaust port (4) of the internal combustion engine (3) for purifying exhaust gas from the internal combustion engine (3). ⁴

An exhaust gas purifying apparatus for an internal combustion engine, wherein a thin steel plate (22) supporting a catalyst metal is disposed at a substantially central portion of a cross section of the exhaust pipe (5).

2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein the thin steel plate (22) is a cylinder extending in an axial direction of the exhaust pipe (5).

3. The exhaust gas purifying apparatus for an internal combustion engine according to claim 2, wherein the cylindrical body is made of a perforated plate, and an exhaust gas upstream side is closed.

4. An internal combustion engine (3), and an exhaust pipe (5) extending from an exhaust port (4) of the internal combustion engine (3) for purifying exhaust gas from the internal combustion engine (3). In the exhaust purification system,

A thin steel plate cylinder (22) extending in the axial direction of the exhaust pipe (5) and carrying a catalyst metal is disposed substantially at the center of the cross section of the exhaust pipe (5). A partition plate (27) for supporting the thin steel plate cylinder (22) and closing a passage between the thin steel plate cylinder (22) and the exhaust pipe (5) is provided. Exhaust purification device for internal combustion engine.

5. The exhaust purification system for an internal combustion engine according to claim 4, wherein the thin steel plate cylinder (22) is attached to the exhaust pipe (5) so as to be able to expand and contract in the axial direction. Device.

6. An internal combustion engine (3), and an exhaust pipe (5) extending from an exhaust port (4) of the internal combustion engine (3) for purifying exhaust gas from the internal combustion engine (3). Exhaust gas purification In the gasifier,

A first carrier (21, 51) supporting a catalyst metal is arranged along the inner wall surface of the exhaust pipe (5), and the catalyst metal is provided substantially at the center of the cross section of the first carrier (21, 51). An exhaust purification device for an internal combustion engine, characterized in that a second carrier (22, 52) carrying the carbon is arranged.

7. The exhaust gas purifying apparatus for an internal combustion engine according to claim 6, wherein the first carrier (51) is made of a cylindrical body, and the second carrier (52) is made of a flat plate.

8. The first carrier (21, 51) and the second carrier (22, 52) have a large number of holes (21a, 51c, 22c, 52a). An exhaust gas purifying apparatus for an internal combustion engine according to claim 1.