WO2021230147A1

WO2021230147A1 - Exhaust catalyst device for internal combustion engine

Info

Publication number: WO2021230147A1
Application number: PCT/JP2021/017478
Authority: WO
Inventors: 良介平松
Original assignee: 株式会社ユタカ技研
Priority date: 2020-05-13
Filing date: 2021-05-07
Publication date: 2021-11-18
Also published as: JP2021179196A

Abstract

The present invention provides an exhaust catalyst device comprising a catalytic converter for exhaust gas purification and a tubular introduction part that guides exhaust gas discharged from an exhaust port of an internal combustion engine to an inlet end surface of the catalytic converter, wherein the introduction part (4) is configured as an inner/outer double-tube structure having an inner (41) and an outer (42), and the downstream side of the inner (41) constitutes a thermal-expansion-allowing section (41a) that is not in contact with a catalytic converter (2) or the outer (42). The inner (41) and the outer (42) are constituted of different metals, and the heat-resistant strength of the metal constituting the inner (41) is higher than the heat-resistant strength of the metal constituting the outer (42). Due to this configuration, an exhaust catalyst device for an internal combustion engine is provided, with which it is possible to guide the exhaust gas to the catalytic converter and purify the exhaust gas while absorbing the heat expansion of the introduction part to minimize damage to the introduction part and the occurrence of abnormal noises, even when the exhaust gas is extremely high in temperature.

Description

Exhaust catalyst device for internal combustion engine

The present invention relates to an exhaust catalyst device including a catalytic converter for purifying exhaust gas discharged from an exhaust port of an internal combustion engine.

The internal combustion engine that converts the heat energy generated by the combustion of the air-fuel mixture into kinetic energy is equipped with an exhaust catalyst device for purifying the exhaust gas discharged from the exhaust port. This exhaust catalyst device includes a catalyst converter for purifying exhaust gas and a tubular introduction portion that guides the exhaust gas discharged from the exhaust port of the internal combustion engine to the inlet end face of the catalyst converter.

By the way, the catalytic converter efficiently fulfills the function of purifying the exhaust gas at a predetermined temperature or higher (for example, 500 ° C. or higher). Therefore, the temperature of the catalytic converter is low for a certain period of time immediately after the start of the internal combustion engine, and the purification efficiency of the exhaust gas by the catalytic converter is low. Therefore, in order to raise the temperature of the catalytic converter at an early stage, the catalytic converter is arranged close to the internal combustion engine side where the exhaust gas temperature is relatively high.

In addition, if the flow of exhaust gas guided from the exhaust port of the internal combustion engine to the catalytic converter via the introduction part of the exhaust catalyst device is non-uniform, the purification efficiency of the catalytic converter will decrease and the catalyst will deteriorate due to partial overheating. Invite.

Therefore, Patent Document 1 proposes an exhaust catalyst device in which the shape of the introduction portion is devised so that the exhaust gas flows from the collecting port of the internal combustion engine to the catalyst converter directly underneath as evenly as possible.

Further, in Patent Document 2, an introduction portion for guiding the exhaust gas to the catalytic converter is provided (inside) in order to make the distribution of the exhaust gas guided to the catalytic converter uniform without deteriorating the warm-up performance of the catalytic converter. An exhaust catalyst device having an inner / outer double structure consisting of a tube) and an outer tube (outer tube) has been proposed.

Japanese Patent Application Laid-Open No. 2007-211663 Japanese Patent Application Laid-Open No. 2003-193835

However, in the exhaust catalyst device proposed in Patent Document 1, since the introduction portion is composed of a single metal plate, the heat resistance strength of the introduction portion is maintained when the exhaust temperature is extremely higher than the conventional one. Therefore, it is necessary to change to a material with high high temperature strength, and a cover or the like is required separately in consideration of the influence on peripheral parts.

Further, in the exhaust catalyst device proposed in Patent Document 2, since the configuration in which the inner is sandwiched between the outer and the case is adopted, the amount of thermal expansion of the inner is limited. In this case, since the inner and other members are in constant contact with each other, when the inner is thermally deformed, the other members are also individually deformed, and cracks and abnormal noise may occur at these contact points.

The present invention has been made in view of the above problems, and an object thereof is to absorb the thermal expansion of the introduction portion even with an extremely high temperature exhaust gas to cause damage to the introduction portion and generation of abnormal noise. It is an object of the present invention to provide an exhaust catalyst device for an internal combustion engine capable of guiding the exhaust gas to a catalytic converter and purifying the exhaust gas while suppressing the exhaust gas.

In order to achieve the above object, the present invention comprises a catalytic converter for purifying exhaust gas and an exhaust catalyst having a tubular introduction portion that guides exhaust gas discharged from an exhaust port of an internal combustion engine to an inlet end surface of the catalytic converter. In the device, the introduction portion is configured as an inner / outer double pipe structure of an inner and an outer, and the downstream side of the inner constitutes a thermal expansion allowable portion that does not come into contact with the catalytic converter and the outer. Is the first feature.

Further, in the present invention, in addition to the first feature, the inner and the outer are each composed of dissimilar metals, and the heat-resistant strength of the metal constituting the inner is the heat-resistant strength of the metal constituting the outer. The second feature is that it is higher than.

Further, in the present invention, in addition to the second feature, the inner and the outer are configured by welding and integrating the press-molded products divided into two, respectively, and the inner and the upstream end of the outer are each other. The third feature is that the joined cylindrical portion is formed, and the cylindrical portion is fitted into the circular hole of the mounting flange.

Further, in the present invention, in addition to the first to third features, the fourth feature is that the thermal expansion allowance portion is arranged close to the outer.

Further, in the present invention, in addition to any of the first to fourth features, a sensor penetrating the outer and the inner is attached to the outer, and the sensor and the through hole of the inner are attached to the outer. The fifth feature is that a gap is formed between them so that they do not come into contact with each other.

Further, in the present invention, in addition to the fifth feature, a boss for attaching the sensor is attached to the outer, and the tubular portion of the boss extends to a position close to the inner. Is the sixth feature.

Further, in addition to the above-mentioned first to sixth features, the seventh feature of the present invention is that a slide member is interposed in the gap between the thermal expansion allowable portion of the inner and the outer. do.

According to the first feature of the present invention, the introduction portion of the exhaust catalyst device is configured as an inner / outer double pipe structure of an inner and an outer, and the downstream side of the inner through which high-temperature exhaust gas flows is allowed to expand thermally. Since it constitutes a part and is free without being restricted by the catalytic converter and the outer, the inner can be freely thermally expanded. Therefore, even when the temperature of the exhaust gas is extremely high, it is possible to prevent damage and abnormal noise due to the difference in thermal expansion between the inner and outer parts. In addition, the space between the inner and the outer forms a heat insulating layer to block the conduction of high-temperature exhaust gas heat to the outer, so that the temperature rise of the outer is suppressed.

Further, according to the second feature of the present invention, the material of the metal constituting the inner and the outer can be selected to be the most suitable for the heating temperature of the inner and the outer. For example, the inner exposed to high-temperature exhaust gas is made of a metal with high heat resistance (for example, austenitic stainless steel), and the outer, which has a lower heating temperature than the inner, is made of ferritic stainless steel, which has excellent workability and strength. This enables a rational design of the introduction section.

Further, according to the third feature of the present invention, the inner and the outer can be easily manufactured by welding and integrating the press-molded products divided into two. Further, the upstream end of the inner and the outer is configured as a cylindrical portion joined to each other, and the cylindrical portion is fitted into the circular hole of the mounting flange to make the mounting flange upstream of the inner and the outer (introduction portion). It can be easily attached to the side end portion, and by attaching this mounting flange to the exhaust side end surface of the cylinder head of the internal combustion engine, the exhaust catalyst device can be attached to the internal combustion engine. In this case, since the upstream end of the introduction portion can be accurately attached to the internal combustion engine by the mounting flange, the downstream end of the introduction portion can be accurately positioned with respect to the catalytic converter.

Further, according to the fourth feature of the present invention, since the thermal expansion allowable portion of the inner is arranged close to the outer, the gap between the inner and the outer is suppressed to a small size, and high-temperature exhaust gas enters this gap. It becomes difficult to prevent the temperature of the outer from becoming locally high due to the exhaust gas.

Further, according to the fifth feature of the present invention, the outer has a sensor penetrating the outer and the inner (for example, a rough sensor for detecting a continuous change in the air-fuel ratio (A / F) of the air-fuel mixture). Since the sensor is attached and a gap is formed between the sensor and the through hole of the inner so that the two do not come into contact with each other, the sensor detects the oxygen concentration in the exhaust gas with high accuracy.

Further, according to the sixth feature of the present invention, since the tubular portion of the boss formed on the outer extends to a position close to the inner, the gap between the sensor and the inner is suppressed to a small size, and the exhaust gas flowing in the inner is suppressed. The inflow to the outer is effectively suppressed. Therefore, the local temperature rise of the outer due to the exhaust gas can be prevented.

Further, according to the seventh feature of the present invention, the downstream end portion of the inner is supported by the slide member interposed in the gap between the thermal expansion allowable portion of the inner and the outer, so that the inner runout is ensured. It can be prevented. Further, since the gap between the inner and the outer is filled by the slide member, the inflow of the exhaust gas from the downstream end side of the inner to the outer is blocked, and the local temperature rise of the outer due to the exhaust gas is prevented. ..

FIG. 1 is a side view of a main part of an internal combustion engine including an exhaust catalyst device according to the present invention. FIG. 2 is a vertical sectional view of an introduction portion of the exhaust catalyst device according to the present invention. FIG. 3 is an exploded perspective view of the introduction portion of the exhaust catalyst device according to the present invention. FIG. 4 is a vertical sectional view of an introduction portion according to another embodiment 1 of the exhaust catalyst device according to the present invention. FIG. 5 is a vertical sectional view of an introduction portion according to another embodiment 2 of the exhaust catalyst device according to the present invention.

1 Exhaust catalyst device 2 Catalyst converter 2a Inlet end face of catalyst converter 2b Outlet end face of catalyst converter 3 Case 4 Introductory part of exhaust catalyst device 5 Derivation part of exhaust catalyst device 6 Mounting flange 6a Circular hole of mounting flange 7 Boss 8 Rough sensor (sensor) )
9 Slide member 10 Internal combustion engine 17 Boss 17a Boss cylinder 41 Inner 41A, 41B Inner half 41a Thermal expansion tolerance 42 Outer 42A, 42B Outer half S Space δ Gap

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

FIG. 1 is a side view of a main part of an internal combustion engine including an exhaust catalyst device according to the present invention, FIG. 2 is a vertical sectional view of an introduction part of the exhaust catalyst device according to the present invention, and FIG. 3 is an exploded view of the introduction part of the exhaust catalyst device. It is a perspective view.

The internal combustion engine 10 shown in FIG. 1 is a 4-cycle multi-cylinder engine, and a plurality of cylinders (not shown) are arranged side by side in the cylinder block 11 in the direction perpendicular to the paper surface of FIG. A piston (not shown) is fitted so that it can slide up and down. Each piston is connected to a crankshaft (not shown) via a connecting rod (not shown).

Further, a cylinder head 12 is attached to the upper part of the cylinder block 11, and a combustion chamber (not shown) is formed in the cylinder head 12 for each cylinder, and each combustion chamber is not shown. The intake port and the exhaust port are open respectively. The intake port and the exhaust port that open in each combustion chamber are opened and closed at appropriate timings by the intake valve and the exhaust valve (not shown) driven by a valve drive mechanism (not shown), which is required in each combustion chamber. Gas exchange is done. In the cylinder head 12, a plurality of exhaust ports extending from the combustion chambers of each cylinder are gathered as a collecting port, and a plurality of exhaust ports are discharged from each combustion chamber on the end face of the cylinder head 12 on the exhaust side. The exhaust gas catalyst device 1 according to the present invention for purifying the exhaust gas that collects and flows from the to the collecting port is connected.

In the internal combustion engine 10 configured as described above, when an air-fuel mixture is supplied to each combustion chamber from an intake port by an injector (not shown), an ignition (not shown) is performed after the air-fuel mixture is compressed by a piston in each combustion chamber. It is ignited and burned by the plug, and each piston slides in each cylinder by the pressure of the exhaust gas generated by the combustion of this air-fuel mixture. Then, the sliding (linear motion) of each piston is converted into the rotary motion of the crank shaft via the conrod, and when the exhaust port is opened by the exhaust valve in each combustion chamber, the high temperature and high pressure exhaust gas is described above. As described above, the exhaust gas is discharged from each combustion chamber, aggregates and flows from a plurality of exhaust ports to the collecting port, and the exhaust gas is purified by the exhaust catalyst device 1 according to the present invention. The exhaust gas purified by passing through the catalyst converter 2 of the exhaust catalyst device 1 is discharged into the atmosphere from the lead-out unit 5 of the exhaust catalyst device 1 through an exhaust pipe and a silencer (not shown).

Here, the details of the exhaust gas purification device 1 according to the present invention will be described.

The exhaust gas purification device 1 according to the present invention is connected to a catalyst converter 2 for purifying exhaust gas, a case 3 accommodating the catalyst converter 2, and an exhaust side end surface of a cylinder head 12 of an internal combustion engine 10 and discharged from an exhaust port. The exhaust gas that is connected to the inlet end surface 2a of the catalyst converter 2 and the exhaust gas that is connected to the outlet end surface 2b of the catalyst converter 2 and purified by the catalyst converter 2 is sent to an exhaust pipe or silencer (not shown). It is composed of a derivation unit 5 for guiding.

The catalyst converter 2 is configured by supporting a precious metal such as platinum or rhodium on a columnar catalyst carrier having a monolithic structure in which a large number of cells are formed, and is housed in a case 3 in a substantially vertically upright state. Has been done. The catalyst converter 2 is provided with an inlet end surface 2a into which the exhaust gas flows in from the introduction unit 4 and an outlet end surface 2b from which the exhaust gas purified by the catalyst converter 2 flows out. The downstream end (lower end) of 4 is connected, and the upstream end (upper end) of the lead-out portion 5 is connected to the outlet end surface 2b.

The introduction portion 4 is a cylindrical member whose upstream end is attached to the exhaust side end surface of the internal combustion engine 10 via the attachment flange 6. The introduction portion 4 extends substantially horizontally from its upstream end toward the rear (to the right in FIG. 1) and then bends vertically downward, and the downstream end extends horizontally to the catalytic converter 2. It is connected to the inlet end surface 2a of the catalyst converter 2.

By the way, as shown in FIG. 2, the introduction portion 4 is configured as an inner / outer double pipe structure of an inner (inner pipe) 41 and an outer (outer pipe) 42, and is located between the inner 41 and the outer 42. A space S is formed in the space S, which constitutes a heat insulating space having a low thermal conductivity. The downstream side of the inner 41 constitutes a thermal expansion allowable portion 41a that does not come into contact with the catalyst converter 2 and the outer 42, and the thermal expansion allowable portion 41a is arranged close to the outer 42. Here, the thermal expansion allowable portion 41a of the inner 41 is not constrained by the catalytic converter 2 and the outer 42, and is in a free state with respect to both. On the other hand, the outer circumference 42 is fixed by fitting the inner circumference of its downstream end (lower end) to the outer circumference of the case 3.

Further, as shown in FIG. 2, circular through

holes

41b and 42a communicating with each other are formed in the upper portions of the inner 41 and the outer 42 of the introduction portion 4, respectively, and are around the through holes 42a of the outer 42. A cylindrical boss 7 is attached to the boss 7 by welding. A rough sensor 8 is passed through the through hole 41b of the boss 7 and the inner 41 from above, and the rough sensor 8 is attached to the boss 7. That is, the rough sensor 8 is attached to the outer 42 via the boss 7, and when the rough sensor 8 is attached, the rough sensor 8 and the through hole 41b of the inner 41 do not come into contact with each other. A sized gap δ is formed. The rough sensor 8 is for detecting a change in the air-fuel ratio (A / F) of the air-fuel mixture, and the oxygen concentration in the exhaust gas detected by the rough sensor 8 is fed back to the air-fuel ratio of the air-fuel mixture. (A / F) is kept at the expected value.

Here, in the present embodiment, the inner 41 and the outer 42 constituting the introduction portion 4 of the exhaust catalyst device 1 are the inner semifield 41A, which is a press-molded product divided into two, as shown in FIG. The 41Bs and the

outer semifields

42A and 42B are welded and integrated, and the upstream end portions of the inner 41 and the outer 42 are joined to each other by the cylindrical portion 41c as shown in FIG. , 42b, respectively. The

cylindrical portions

41c and 42b of the inner 41 and the outer 42 are fitted into the circular holes 6a of the mounting flange 6. Therefore, the mounting flange 6 is mounted at the upstream end of the introduction portion 4, and the upstream end of the introduction portion 4 uses a bolt or band (not shown) to attach the mounting flange 6 to the exhaust side end surface of the cylinder head 12 of the internal combustion engine 10. By attaching to FIG. 1), the upstream end of the introduction portion 4 is attached to the exhaust side end surface of the cylinder head 12 of the internal combustion engine 10 via the attachment flange 6.

By the way, the inner 41 and the outer 42 constituting the introduction portion 4 are made of dissimilar metals, and the inner 41 in which the high-temperature exhaust gas flows inside is more than the metal constituting the outer 42 having a lower temperature than the inner 41. Is also composed of a metal with high heat resistance. Specifically, austenitic stainless steel (SUS316L) having high heat resistance and corrosion resistance is used as the metal constituting the inner 41, and ferritic stainless steel having excellent workability and strength is used as the metal constituting the outer 42. (SUS444, etc.) is used.

In the present embodiment, as shown in FIG. 3, a tubular shape as shown in FIG. 2 is formed by welding the peripheral edges of the openings of the

inner semifields

41A and 41B obtained by press-molding an austenitic stainless steel plate. Inner 41 is obtained. Similarly, by welding the peripheral edges of the openings of the

outer semifields

42A and 42B obtained by press-molding a ferritic stainless steel plate, a tubular outer 42 as shown in FIG. 2 can be obtained. As shown in FIG. 3, semicircular holes 41b1 and 41b2 are formed in the upper portions of the

inner halves

41A and 41B, respectively, and these

inner halves

41A and 41B are welded and integrated to each other. At the upper part of the inner 41, a circular through hole 41b (see FIG. 2) formed by combining the semicircular holes 41b1 and 41b2 is formed. Similarly, semicircular holes 42a1 and 42a2 are formed in the upper portions of the

outer half bodies

42A and 42B, respectively, and in the upper portion of the outer 42 obtained by welding and integrating these

outer half bodies

42A and 42B with each other. , A circular hole-shaped through hole 42a (see FIG. 2) formed by combining the semicircular holes 42a1 and 42a2 is formed, and the boss 7 is inserted through the through hole 42a and welded to the outer 42.

As described above, the introduction unit 4 constituting a part of the exhaust catalyst device 1 according to the present invention is configured as an inner / outer double pipe structure of the inner 41 and the outer 42, and the inner 41 through which high-temperature exhaust gas flows inside. Since the downstream side of the inner 41 constitutes a thermal expansion allowable portion 41a and is not constrained by the catalytic converter 2 and the outer 42 and is free of charge, the inner 41 can be freely thermally expanded. Therefore, even when the temperature of the exhaust gas is extremely high, it is possible to prevent damage and abnormal noise due to the difference in thermal expansion between the inner 41 and the outer 42.

Further, the space S between the inner 41 and the outer 42 forms a heat insulating layer to block the conduction of high-temperature exhaust gas heat to the outer 42, so that the temperature rise of the outer 42 is suppressed.

Further, in the present embodiment, the material of the metal constituting the inner 41 and the outer 42 is selected to be the most suitable for the heating temperature of the inner 41 and the outer 42. For example, the inner 41 exposed to high-temperature exhaust gas is made of austenitic stainless steel, which is a metal with high heat resistance, and the outer 42, which has a lower heating temperature than the inner 41, is made of ferritic stainless steel, which has excellent workability and strength. Therefore, the rational design of the introduction unit 4 becomes possible.

Then, in the present embodiment, the inner 41 and the outer 42 are easily integrated by welding the

inner semifields

41A and 41B, which are press-molded products divided into two, and the

outer semifields

42A and 42B, respectively. Can be manufactured to. Further, the upstream end portions of the inner 41 and the outer 42 are configured as

cylindrical portions

41c and 42b joined to each other, and the

cylindrical portions

41c and 42b are fitted into the circular holes 6a of the mounting flange 6 to fit the mounting flange. 6 can be easily attached to the upstream end of the inner 41 and the outer 42, and by attaching this mounting flange 6 to the exhaust side end surface of the cylinder head 12 (see FIG. 1) of the internal combustion engine 10, the exhaust catalyst device is concerned. 1 can be attached to the internal combustion engine 10. In this case, since the upstream end of the introduction portion 4 can be accurately attached to the internal combustion engine 10 by the mounting flange 6, the downstream end of the introduction portion 4 is accurately positioned with respect to the catalytic converter 2. be able to.

Further, in the present embodiment, since the thermal expansion allowable portion 41a of the inner 41 is arranged close to the outer 42, the gap between the inner 41 and the outer 42 is suppressed to a small size, and high-temperature exhaust gas is discharged in this gap. It becomes difficult to enter, and it is possible to prevent the temperature of the outer 42 from becoming locally high due to the exhaust gas.

Further, in the present embodiment, a rough sensor 8 penetrating the outer 42 and the inner 41 is attached to the outer 42 so that the rough sensor 8 and the through hole 41b of the inner 41 do not come into contact with each other. Since the gap δ is formed, the oxygen concentration in the exhaust gas can be detected with high accuracy by the rough sensor 8.

Here, other forms of the introduction unit 4 of the exhaust catalyst device 1 according to the present invention are shown in FIGS. 4 and 5, respectively. In FIGS. 4 and 5, the same elements as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted below.

That is, FIG. 4 is a vertical sectional view of an introduction portion 4 according to another embodiment 1 of the exhaust catalyst device 1 according to the present invention. In this embodiment, a boss 17 for attaching a rough sensor 8 is attached to the outer 42. However, the tubular portion 17a of the boss 17 extends to a position close to the inner 41. When the tubular portion 17a of the boss 17 is extended to a position close to the inner 41 in this way, the gap between the rough sensor 8 and the inner 41 is suppressed to a small size, and the inflow of exhaust gas flowing through the inner 41 into the outer 42 is effective. Therefore, it is possible to obtain the effect of preventing the local temperature rise of the outer 42 due to the exhaust gas.

Further, FIG. 5 is a vertical cross-sectional view of the introduction portion 4 according to another embodiment 2 of the exhaust catalyst device 1 according to the present invention. In this embodiment, the gap between the thermal expansion allowable portion 41a of the inner 41 and the outer 42 is taken. A ring-shaped slide member 9 is interposed.

By adopting the above configuration, since the downstream end portion of the inner 41 is supported by the slide member 9, the runout of the inner 41 is surely prevented. Further, since the gap between the inner 41 and the outer 42 is filled by the slide member 9, the inflow of the exhaust gas from the downstream end side of the inner 41 to the outer 42 is blocked, and the exhaust gas causes the outer 42 to be localized. The effect of preventing high temperature can be obtained.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that various modifications can be made within the scope of the gist thereof.

Claims

An exhaust catalyst device including a catalytic converter for purifying exhaust gas and a tubular introduction portion that guides exhaust gas discharged from an exhaust port of an internal combustion engine to an inlet end face of the catalytic converter.
The introduction portion is configured as an inner / outer double pipe structure of an inner and an outer.
An exhaust catalyst device for an internal combustion engine, characterized in that a downstream side of the inner portion constitutes a thermal expansion allowable portion that does not come into contact with the catalytic converter and the outer.
The first aspect of claim 1, wherein the inner and the outer are each composed of dissimilar metals, and the heat-resistant strength of the metal constituting the inner is higher than the heat-resistant strength of the metal constituting the outer. Exhaust catalyst device for internal combustion engine.
The inner and the outer are each formed by welding and integrating a press-molded product divided into two, and the upstream end of the inner and the outer form a cylindrical portion joined to each other, and the cylindrical portion is attached. The exhaust catalyst device for an internal combustion engine according to claim 2, wherein the exhaust catalyst device is fitted in a circular hole of a flange.
The exhaust catalyst device for an internal combustion engine according to any one of claims 1 to 3, wherein the thermal expansion allowable portion is arranged close to the outer.
A sensor penetrating the outer and the inner is attached to the outer, and a gap is formed between the sensor and the through hole of the inner so that the two do not come into contact with each other. The exhaust catalyst device for an internal combustion engine according to any one of claims 1 to 4.
The exhaust gas of an internal combustion engine according to claim 5, wherein a boss for attaching the sensor is attached to the outer, and the tubular portion of the boss extends to a position close to the inner. Catalyst device.
The exhaust catalyst device for an internal combustion engine according to any one of claims 1 to 6, wherein a slide member is interposed in a gap between the thermal expansion allowable portion of the inner and the outer.