JP5126125B2 - Exhaust gas purification device - Google Patents

Description

  The present invention relates to an exhaust gas purification device, and more particularly to an exhaust gas purification device having a holding means for holding a combustion catalyst carrier that supports a catalyst for burning fuel in an exhaust pipe.

  In general, particulates discharged from a diesel engine are mainly composed of soot made of carbon and SOF content (soluble organic fraction) consisting of boiling hydrocarbon components, and a trace amount of sulfate (mist-like sulfuric acid). In order to reduce this kind of particulates, a particulate filter (hereinafter simply referred to as DPF) as a purification means is provided on the exhaust pipe through which the exhaust gas flows. It is known.

  This type of conventional DPF has a porous honeycomb structure, and the inlets of the flow paths partitioned in a lattice pattern are alternately sealed, and the outlets of the flow paths not sealed with the inlets are the outlets. Is sealed, and only the exhaust gas that has permeated through the porous thin wall that defines each flow path is discharged downstream.

  And since the particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall, the particulates are appropriately burned and removed before the exhaust resistance increases due to clogging. Therefore, it is necessary to regenerate the DPF.

  However, in normal diesel engine operating conditions, there are few opportunities to obtain exhaust temperatures that are high enough for particulates to self-combust. For example, HC and CO in exhaust gas are oxidized by catalytic action upstream of the DPF. An oxidation catalyst is provided as a purifying means, and PM deposited on the DPF is burned by utilizing reaction heat generated when HC or the like is oxidized and burned by the oxidation catalyst.

  However, even when such an oxidation catalyst is used to regenerate the DPF, in the operation region where the exhaust gas temperature is low, such as during cold operation, the amount of particulates collected is higher than the particulate processing amount. If the operation state at such a low exhaust temperature continues, there is a risk that the regeneration of the DPF does not proceed well and the DPF falls into an over-collected state.

  Conventionally, as a device that can regenerate the DPF even in an operation region where the exhaust gas temperature is low, such as during cold operation, for example, a device in which a combustion catalyst is provided upstream of the DPF is known (for example, patents). Reference 1).

  This combustion catalyst has an exhaust gas flow passage surrounded by partition walls having a honeycomb structure, the inner peripheral surface of the partition walls is coated with a coating material, and a metal catalyst that burns fuel is dispersed and supported on the coating material. It is configured to supply a mixed gas of fuel and air to the combustion catalyst for catalytic combustion.

  Then, by passing the exhaust gas through this high-temperature combustion catalyst, the DPF can be regenerated by raising the temperature of the exhaust gas to a temperature at which the particulates can be combusted (about 500 ° C.).

  Since this combustion catalyst is provided on the upstream side of the oxidation catalyst and the DPF, in order to prevent the exhaust resistance of the exhaust gas from increasing, the exhaust gas is provided between the exhaust pipe and the central portion in the axial direction of the exhaust pipe. (See, for example, Patent Document 2), and a specific structure for attaching the combustion catalyst to the exhaust pipe is as shown in FIG. Conceivable.

  In FIG. 19, the combustion catalyst 1 is provided in the central portion in the axial direction of the exhaust pipe 2, and is connected to the exhaust pipe 2 by a plurality of plate-like members 3. The plate-like member 3 has a bottom surface 3 a fixed to the inner peripheral surface of the exhaust pipe 2 by a welded portion 4 and a tip 3 b fixed to the outer peripheral portion of the combustion catalyst 1 by a welded portion 5.

  The combustion catalyst 1 is formed of a cylindrical carrier, and includes an exhaust gas flow passage 1b in which an inner peripheral portion of the carrier is surrounded by a partition wall 1a having a honeycomb structure. And the inner peripheral surface of the partition 1a is coat | covered with the coating material, and the metal catalyst combusted with a fuel is disperse | distributed and carry | supported on this coating material.

  In this way, by attaching the combustion catalyst 1 to the exhaust pipe 2 between the plurality of plate-like members 3, the gap S is defined between the plate-like members 3, so that the exhaust gas is passed through the gap S through the oxidation catalyst and Since it can supply to DPS, it can prevent that the exhaust resistance of exhaust gas increases.

JP-A-11-169709 JP 2005-127257 A

  However, in such a conventional combustion catalyst 1, since the tip 3b of the plate-like member 3 is fixed to the outer peripheral portion of the combustion catalyst 1 by the welded portion 5, the combustion is started from the state shown in FIG. When fuel is supplied to the catalyst 1 and the combustion catalyst 1 is thermally expanded as shown in FIG. 20B, the plate-like member 3 may be damaged or the weld 5 may be burned.

  That is, when the combustion catalyst 1 is thermally expanded, the combustion catalyst 1 is expanded and the surface area is increased, so that the plate-like member 3 is curved as the surface area of the combustion catalyst 1 is increased.

  Then, when the combustion catalyst 1 becomes a low temperature state and the combustion catalyst 1 returns to the original state, the plate-like member 3 becomes a linear state. By repeating the state, thermal stress is accumulated in the curved portion of the plate-like member 3, and in the worst case, the plate-like member 3 may be damaged.

  Further, when the combustion catalyst 1 is thermally expanded and the surface area of the combustion catalyst 1 is increased, a displacement between the tip 3b of the plate member 3 and the outer peripheral portion of the combustion catalyst 1 occurs (see FIG. 21). For this reason, while the combustion catalyst 1 repeats the low temperature state and the high temperature state, the welded portion 5 that fixes the tip 3b of the plate-like member 3 to the outer peripheral portion of the combustion catalyst 1 is easily peeled off.

  As described above, in the conventional holding structure, the plate-like member 3 is easily damaged by the thermal expansion of the combustion catalyst 1, and the welded portion 5 is easily peeled off, so that the combustion catalyst 1 is attached to the exhaust pipe 2 by the plate-like member 3. There is a problem that it is difficult to stably hold, and the reliability of the holding structure of the combustion catalyst 1 deteriorates.

  The present invention has been made to solve the conventional problems as described above, and provides a highly reliable exhaust gas purifying apparatus capable of stably holding a combustion catalyst carrier in an exhaust pipe by a holding member. The purpose is to do.

  In order to achieve the above object, an exhaust gas purifying apparatus according to the present invention provides (1) a purifying means that is disposed in an exhaust pipe of an internal combustion engine and purifies exhaust gas discharged from the internal combustion engine; A cylindrical combustion catalyst carrier disposed upstream of the exhaust gas in the exhaust pipe and carrying a catalyst for burning fuel, and positioned upstream of the combustion catalyst in the exhaust gas exhaust direction. In the exhaust gas purifying apparatus comprising a fuel supply means for supplying fuel into the exhaust pipe, the combustion is performed so that a gap is defined between the periphery of the combustion catalyst carrier and the inner periphery of the exhaust pipe. A holding member that holds the catalyst carrier in the exhaust pipe, and the holding member holds the combustion catalyst carrier so as to absorb displacement due to thermal expansion of the combustion catalyst carrier; .

  With this configuration, the holding member provided in the exhaust gas purification device holds the combustion catalyst carrier so as to absorb the displacement due to the thermal expansion of the combustion catalyst carrier, so that the holding member during expansion / contraction of the combustion catalyst carrier Therefore, it is possible to prevent thermal stress from being accumulated, and it is possible to prevent the holding member from being damaged.

  In addition to this, it is possible to prevent the portion where the holding member is attached to the combustion catalyst carrier from peeling off from the combustion catalyst carrier. For this reason, the combustion catalyst carrier can be stably attached to the exhaust pipe, and the reliability of the exhaust gas purification device can be improved.

  In the exhaust gas purifying apparatus according to (1) above, (2) the holding means includes a base end portion whose bottom surface is fixed to the inner peripheral portion of the exhaust pipe, and the base end portion to the combustion catalyst carrier. A plurality of plates extending in the extending direction of the combustion catalyst carrier, the one side surface substantially projecting toward the bottom surface and having a tip portion fixed to the outer periphery of the combustion catalyst carrier. The plurality of plate-like members are configured to hold the combustion catalyst carrier so as to surround the combustion catalyst carrier around the center axis of the combustion catalyst carrier.

  With this configuration, the plate member extends in the extending direction of the combustion catalyst carrier, and one side surface of the tip of the plate member substantially orthogonal to the bottom plate of the plate member is welded to the combustion catalyst carrier. Since the plurality of plate-like members hold the combustion catalyst carrier so as to surround the combustion catalyst carrier around the central axis of the combustion catalyst carrier, the combustion catalyst carrier is thermally expanded to support the combustion catalyst. When the surface area of the body increases, the plate-like member extends linearly due to the influence of the combustion catalyst carrier that has reached a high temperature. For this reason, the combustion catalyst carrier rotates and the plate-like member can absorb the displacement due to the thermal expansion of the combustion catalyst carrier.

  Further, when the combustion catalyst carrier becomes low temperature and the surface area of the combustion catalyst carrier becomes small (in the original state), the plate-like member contracts linearly and the combustion catalyst carrier expands. It rotates in the opposite direction to the hour. For this reason, when the combustion catalyst carrier repeatedly expands and contracts, thermal stress is not accumulated in the plate member, and the plate member can be prevented from being damaged.

  In addition, since one side surface of the protruding end of the plate-like member is fixed to the combustion catalyst carrier, the plate-like member is fixed in the same position on the outer peripheral portion of the combustion catalyst carrier. Since the combustion catalyst carrier rotates as the member expands and contracts, it is possible to prevent one side surface of the protruding end of the plate-like member from being peeled off from the combustion catalyst carrier.

  As a result, the combustion catalyst carrier can be stably attached to the exhaust pipe via the holding member, and the reliability of the exhaust gas purification device can be improved.

  In the exhaust gas purifying apparatus according to the above (1), (3) the cylindrical combustion catalyst carrier is located between the large-diameter cylindrical portion and the large-diameter cylindrical portion, and the large-diameter cylindrical shape The holding means is integrally formed with an inner peripheral portion of the exhaust pipe and is fitted to the small diameter cylindrical portion between the both end portions. A plurality of holding members each having a fitting portion to be held, and holding the combustion catalyst carrier by sandwiching the small-diameter cylindrical portion by the fitting portion.

  With this configuration, the plurality of holding members have a fitting portion that is fitted to the small-diameter cylindrical portion of the combustion catalyst carrier, and the combustion catalyst carrier is held by sandwiching the small-diameter cylindrical portion by the fitting portion. Therefore, the combustion catalyst carrier can be held in the exhaust pipe by the holding member when the bottom surface of the large diameter cylindrical portion located above the small diameter cylindrical portion comes into contact with the holding member.

  Further, when the surface area of the small-diameter cylindrical portion of the combustion catalyst carrier increases due to thermal expansion of the combustion catalyst carrier, the fitting portion expands due to the influence of the combustion catalyst carrier that has become high temperature. Displacement due to thermal expansion of the carrier can be absorbed.

Further, since the combustion catalyst carrier is held by sandwiching the small-diameter cylindrical portion by the fitting portion, it is unnecessary to fix the fitting portion to the combustion catalyst carrier by welding or the like, and the fitting portion is cylindrical. The situation where it peels off from a small diameter part does not arise.
As a result, the combustion catalyst carrier can be stably attached to the exhaust pipe via the holding member, and the reliability of the exhaust gas purification device can be improved.

  According to the present invention, it is possible to provide a highly reliable exhaust gas purifying apparatus capable of stably holding a combustion catalyst carrier in an exhaust pipe by a holding member.

1 is a diagram illustrating a first embodiment of an exhaust gas purification device according to the present invention, and is a schematic configuration diagram of an internal combustion engine including the exhaust gas purification device. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the exhaust gas purification apparatus which concerns on this invention, (a) is a perspective view of the combustion catalyst support body and plate-shaped member which are attached to an exhaust pipe, (b) is an exhaust pipe. It is a top view of the combustion catalyst support body and plate member to be attached. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a figure which shows the state of a combustion catalyst carrier and a plate-shaped member when a combustion catalyst carrier is a low temperature state, (B) is a figure which shows the state of a combustion catalyst carrier and a plate-shaped member when a combustion catalyst carrier is thermally expanded. It is a figure which shows 1st Embodiment of the exhaust-gas purification apparatus which concerns on this invention, and is a figure which shows the positional relationship of a holding member and a combustion catalyst carrier when a combustion catalyst carrier is low-temperature and thermally expanded. . BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a perspective view of the plate-shaped member of the combustion catalyst support body and other structure attached to an exhaust pipe, (b) FIG. 5 is a top view of a combustion catalyst carrier attached to an exhaust pipe and a plate member having another configuration. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a perspective view of the plate-shaped member of the combustion catalyst support body and other structure attached to an exhaust pipe, (b) FIG. 5 is a top view of a combustion catalyst carrier attached to an exhaust pipe and a plate member having another configuration. It is a figure which shows 2nd Embodiment of the exhaust-gas purification apparatus which concerns on this invention, and is an external view of a combustion catalyst carrier. It is a figure which shows 2nd Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a perspective view of the combustion catalyst support body and plate-shaped member which are attached to an exhaust pipe, (b) is an exhaust pipe FIG. 3 is a top view of a combustion catalyst carrier and a plate-like member attached to the cylinder. It is a figure which shows 2nd Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a figure which shows the state of a combustion catalyst support body and a plate-shaped member when a combustion catalyst support body is a low-temperature state, (B) is a figure which shows the state of a combustion catalyst carrier and a plate-shaped member when a combustion catalyst carrier is thermally expanded. It is a figure which shows 3rd Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a perspective view of the combustion catalyst support body and plate-shaped member which are attached to an exhaust pipe, (b) is a holding member FIG. It is a figure which shows 3rd Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a top view of the combustion catalyst carrier and plate-like member seen from the large diameter cylindrical part side, (b) FIG. 3 is a top view of a combustion catalyst carrier and a plate-like member when the small-diameter cylindrical portion is viewed from above on a surface obtained by cutting the bottom portion of the large-diameter cylindrical portion and the upper portion of the small-diameter cylindrical portion. It is a figure which shows 4th Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is a perspective view of the plate-shaped member of the combustion catalyst support body and other structure attached to an exhaust pipe, (b) FIG. 3 is a top view of a combustion catalyst carrier and a plate-like member when the small-diameter cylindrical portion is viewed from above on a surface obtained by cutting the bottom portion of the large-diameter cylindrical portion and the upper portion of the small-diameter cylindrical portion. It is a figure which shows 4th Embodiment of the exhaust-gas purification apparatus which concerns on this invention, (a) is an external view of the decomposed | disassembled plate-shaped member, (b) is when a plate-shaped member is integrated. It is an external view. It is a figure which shows 5th Embodiment of the exhaust gas purification apparatus which concerns on this invention, and is a perspective view of the combustion catalyst carrier attached to an exhaust pipe and the plate-shaped member of another structure, (b) is an exhaust pipe It is a top view of the combustion catalyst support body and plate member to be attached. It is a figure which shows 5th Embodiment of the exhaust gas purification apparatus which concerns on this invention, and is a disassembled perspective view of a combustion catalyst carrier, a holding member, and a net | network member. It is a figure which shows 5th Embodiment of the exhaust gas purification apparatus which concerns on this invention, (a) is a figure which shows the positional relationship of a combustion catalyst carrier and a holding member when a combustion catalyst carrier is in a low temperature state. (B) is a figure which shows the positional relationship of a combustion catalyst carrier and a holding member when a combustion catalyst carrier is thermally expanded. It is a figure which shows 6th Embodiment of the exhaust gas purification apparatus which concerns on this invention, and is a top view of the combustion catalyst support body and plate-shaped member which are attached to an exhaust pipe. It is a figure which shows 6th Embodiment of the exhaust gas purification apparatus which concerns on this invention, (a) is XX direction sectional drawing of FIG. 17 when a combustion catalyst support body is in a low-temperature state, (b) FIG. 18 is a cross-sectional view in the XX direction of FIG. 17 when the combustion catalyst carrier is thermally expanded. (A) is a perspective view of the conventional combustion catalyst carrier and plate-like member attached to the exhaust pipe, and (b) is a top view of the conventional combustion catalyst carrier and plate-like member attached to the exhaust pipe. (A) is a figure which shows the state of the conventional combustion catalyst support body and plate-shaped member when a combustion catalyst support body is a low-temperature state, (b) is the conventional combustion catalyst when a combustion catalyst support body expands thermally. It is a figure which shows the state of a support body and a plate-shaped member. It is a figure which shows the state of the welding part of the conventional plate-shaped member and combustion catalyst carrier when a combustion catalyst carrier is thermally expanded.

Hereinafter, embodiments of an exhaust gas purifying apparatus according to the present invention will be described with reference to the drawings.
(First embodiment)
First, the configuration will be described.
In FIG. 1, an internal combustion engine 11 is a compression ignition type internal combustion engine (diesel engine) having four cylinders 12, and a fuel injection valve 13 for directly injecting fuel into each cylinder 12 is attached to the internal combustion engine 11. It has been.

  Air is introduced into each cylinder 12 via an intake pipe 14, and the air introduced into each cylinder 12 is combusted together with fuel injected from the fuel injection valve 13. .

  Further, the exhaust gas (burned gas) burned in each cylinder 12 is discharged to a cylindrical exhaust pipe 15, and the exhaust gas discharged from the internal combustion engine 11 to the exhaust pipe 15 is a catalyst. It is discharged into the atmosphere through the casing 16.

  The catalyst casing 16 houses an oxidation catalyst 17 and a DPF 18 positioned downstream of the oxidation catalyst 17. The oxidation catalyst 17 is an open type having a straight flow structure, and includes a plurality of straight cells in which exhaust gas is DC, straight cell partitions partitioning the straight cells, and an oxidation having oxidation activity formed on the surface of the straight cell partitions. HC (hydrocarbon) in the exhaust gas in which a catalytic metal such as platinum is supported on a coating layer made of a porous oxide such as alumina, and DC is passed through a straight cell. And CO (carbon monoxide) are oxidized and burned by the catalytic action of the catalytic metal.

  Further, the DPF 18 has a porous honeycomb structure, and the inlets of the respective flow paths partitioned in a lattice pattern are alternately sealed, and the outlets of the flow paths in which the inlets are not sealed are sealed. Only the exhaust gas that has permeated through the porous thin wall partitioning each flow path is discharged to the downstream side. The particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall. Further, an NOx storage reduction catalyst may be added as a purification means.

  The intake pipe 14 and the exhaust pipe 15 are provided with a turbocharger 19, which is sent from an air cleaner (not shown) to the compressor 19 a of the turbocharger 19 through the intake pipe 14, and the intake air pressurized by the compressor 19 a is intercooled. After being sent to the cooler 20 and cooled, it is led from the intercooler 20 to the intake manifold 21 and distributed to each cylinder 12 of the internal combustion engine 11.

  Further, the exhaust gas discharged from each cylinder 12 of the internal combustion engine 11 is sent to the turbine 19b of the turbocharger 19 via the exhaust manifold 22, and the exhaust gas that has driven the turbine 19b is sent to the exhaust pipe 15, and the catalyst casing. 16 and then released into the atmosphere.

  On the other hand, a combustion catalyst 23 is provided upstream of the oxidation catalyst 17, and this combustion catalyst 23 includes a combustion catalyst carrier 24 made of cylindrical ceramics or the like as shown in FIG. A partition wall 24a having a honeycomb structure is provided on the inner peripheral portion of the combustion catalyst carrier 24, and an exhaust gas flow passage 24b surrounded by the partition wall 24a is formed.

  A coating layer is formed by coating the surface of the partition wall 24a with a coating material made of γ-alumina or the like, and a noble metal catalyst such as platinum or rhodium burned by fuel is dispersed and supported on the coating layer. Has been.

  The exhaust pipe 15 upstream of the combustion catalyst 23 is provided with a fuel injection valve 25 as fuel supply means. The fuel injection valve 25 injects fuel toward the combustion catalyst 23. . Although not shown, a guide member that guides the fuel injected from the fuel injection valve 25 to the combustion catalyst 23 may be provided between the fuel injection valve 25 and the combustion catalyst 23.

  Further, the combustion catalyst carrier 24 of the combustion catalyst 23 is located in the center in the axial direction of the exhaust pipe 15, and a gap is defined between the periphery of the combustion catalyst carrier 24 and the inner peripheral part of the exhaust pipe 15. In this manner, the holding means 26 holds the exhaust pipe 15 on the inner periphery.

  The holding means 26 is composed of four linear plate members 27, and the plate members 27 extend along the longitudinal direction of the combustion catalyst carrier 24. Here, the longitudinal direction of the combustion catalyst carrier 24 is the same as the exhaust direction of the exhaust gas.

  The plate-like member 27 has a base end portion 27A whose bottom surface 27a is fixed to the inner peripheral portion of the exhaust pipe 15 by a welded portion 28a, and projects from the base end portion 27A toward the combustion catalyst carrier 24, and is substantially the same as the bottom surface 27a. One orthogonal side surface 27b has a tip end portion 27B fixed to the outer peripheral portion of the combustion catalyst support 24 by a welded portion 28b.

The plurality of plate-like members 27 hold the combustion catalyst carrier 24 around the central axis O of the combustion catalyst carrier 24 so as to surround the combustion catalyst carrier 24. A gap S is formed. For this reason, the exhaust resistance of the exhaust gas can be reduced by allowing the exhaust gas to flow through the outer peripheral portion of the combustion catalyst support 24 through the gap S. In addition, a weld part means the state of the result of welding, and it is the same also in the following description.
In the present embodiment, as shown in FIG. 1, the oxidation catalyst 17, the DPF 18, the combustion catalyst 23, and the fuel injection valve 25 constitute an exhaust gas purification device 31.

  In the present embodiment, particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall of the DPF 18 to suppress the particulates from being discharged to the outside. When the supplemental amount of particulates increases, exhaust resistance increases due to clogging. Therefore, it is necessary to regenerate the DPF 18 by burning and removing particulates appropriately.

  In the present embodiment, since the oxidation catalyst 17 that oxidizes HC, CO, etc. in the exhaust gas by catalytic action is provided upstream of the DPF 18, this occurs when the oxidation catalyst 17 oxidizes and burns HC, etc. The PM deposited on the DPF 18 can be burned using the reaction heat.

  However, even if the oxidation catalyst 17 is used to regenerate the DPF 18, the trapping amount is higher than the particulate processing amount in the operation region where the exhaust temperature is low, such as during cold operation. Therefore, if the operation state at such a low exhaust temperature continues, there is a possibility that the regeneration of the DPF 18 does not proceed well and the DPF 18 falls into an over trapped state.

  Therefore, in the present embodiment, fuel is injected from the fuel injection valve 25 to the combustion catalyst 23 and the mixed gas of fuel and air is supplied to the combustion catalyst 23 in an operation region where the exhaust temperature is low, such as during cold operation. Then, the DPF 18 is regenerated by raising the temperature of the exhaust gas to a temperature at which the particulates can be combusted (about 500 ° C.) by passing the exhaust gas through the high-temperature combustion catalyst 23.

  However, when the combustion catalyst carrier 24 becomes high temperature, the combustion catalyst carrier 24 expands and the surface area of the combustion catalyst carrier 24 increases.

  In the present embodiment, the plate member 27 extends in the extending direction of the combustion catalyst carrier 24, that is, the exhaust gas exhaust direction, and is substantially orthogonal to the bottom surface 27a of the plate member 27. 27 is fixed to the outer peripheral portion of the combustion catalyst carrier 24 by a welded portion 28b, and a plurality of plate-like members 27 are disposed around the central axis O of the combustion catalyst carrier 24. Since the combustion catalyst carrier 24 is held in the exhaust pipe 15 so as to surround the cylinder 24, when the combustion catalyst carrier 24 is thermally expanded and the surface area of the combustion catalyst carrier 24 is increased, FIG. As shown in FIG. 3B, the plate-like member 27 extends linearly due to the influence of the combustion catalyst carrier 24 that has become high temperature. For this reason, the combustion catalyst carrier 24 rotates and the plate-like member 27 can absorb the displacement due to the thermal expansion of the combustion catalyst carrier.

  In addition, when the combustion catalyst carrier 24 is at a low temperature (for example, 25 ° C.) and the surface area of the combustion catalyst carrier 24 is reduced (becomes the original state), the plate member 27 contracts linearly. At the same time, the combustion catalyst carrier 24 rotates in the opposite direction to that during expansion. For this reason, when the combustion catalyst carrier 24 repeatedly expands and contracts, thermal stress is not accumulated in the plate member 27, and the plate member 27 can be prevented from being damaged.

  Further, since one side surface 27b of the tip portion 27B of the plate member 27 is fixed to the combustion catalyst carrier 24, the one side surface 27b of the plate member 27 is the outer periphery of the combustion catalyst carrier 24 as shown in FIG. The combustion catalyst carrier 24 can be rotated as the plate member 27 expands and contracts in a state of being fixed at the same position of the portion, and one side surface 27b of the plate member 27 is the combustion catalyst carrier 24. Can be prevented from being peeled off.

  As a result, the combustion catalyst carrier 24 can be stably attached to the exhaust pipe 15 via the plate-like member 27, and the reliability of the exhaust gas purification device 31 can be improved.

  In this embodiment, four plate-like members 27 are provided. However, three plate members 27 may be provided as shown in FIG. 5, or five or six or more members may be provided as shown in FIG. Good.

(Second Embodiment)
In FIG. 7, the combustion catalyst 40 includes a combustion catalyst carrier 41 made of cylindrical ceramics or the like. The combustion catalyst carrier 41 includes large-diameter cylindrical portions 41a and 41c and a large-diameter cylindrical portion 41a. , 41c, and is integrally formed with a small-diameter cylindrical portion 41b having a smaller diameter than the large-diameter cylindrical portions 41a and 41c. The large-diameter cylindrical portions 41a and 41c are formed to have the same diameter. ing.

  An exhaust gas flow passage 43 surrounded by a partition wall 42 having a honeycomb structure is formed in the inner peripheral portions of the large diameter tubular portions 41a and 41c and the small diameter tubular portion 41b, and the flow passage 43 has a large diameter tubular shape. It extends over the parts 41a and 41c and the small diameter cylindrical part 41b. Further, the flow passage 43 extends in the radial direction of the large-diameter cylindrical portions 41a and 41c excluding the small-diameter cylindrical portion 41b in the extending direction of the large-diameter cylindrical portions 41a and 41c, that is, the exhaust gas exhaust direction. It is extended.

  The combustion catalyst carrier 41 has a coating layer formed by coating the surface of the partition wall 42 with a coating material made of γ-alumina or the like, and platinum, rhodium, etc. burned by the fuel on the coating layer The noble metal catalyst is dispersed and supported.

  On the other hand, as shown in FIG. 8, the combustion catalyst carrier 41 is located in the center in the axial direction of the exhaust pipe 15, and a gap S is formed between the periphery of the combustion catalyst carrier 41 and the inner peripheral part of the exhaust pipe 15. Is held in the exhaust pipe 15 by holding members 44 and 45 as holding means.

  The holding members 44 and 45 have one end portions 44a and 45a and other end portions 44b and 45b, which are both ends, fixed to the inner peripheral portion of the exhaust pipe 15 by a welded portion 46, and the one end portions 44a and 45a and the other end portion. Semicircular curved portions 44c and 45c as fitting portions are formed between the small diameter cylindrical portion 41b between 44b and 45b (see FIG. 9A). The curved portions 44c and 45c are located at a substantially central portion in the extending direction of the holding members 44 and 45, and the curved portions 44c and 45c are curved along the curved surface of the small-diameter cylindrical portion 41b.

  The curved portions 44c and 45c of the holding members 44 and 45 are fitted into the small diameter cylindrical portion 41b so as to sandwich the small diameter cylindrical portion 41b, and are in close contact with the small diameter cylindrical portion 41b. 41 is held.

  Further, a clearance S is formed between the holding members 44 and 45 and the inner peripheral portion of the exhaust pipe 15, and the exhaust gas is allowed to flow through the outer peripheral portion of the combustion catalyst support 41 through the clearance S. The exhaust resistance can be reduced.

  In the present embodiment, the holding members 44 and 45 have curved portions 44c and 45c fitted to the small diameter cylindrical portion 41b of the combustion catalyst support 41, and the small diameter cylindrical portion 41b is formed by the curved portions 44c and 45c. Since the combustion catalyst carrier 41 is held by being sandwiched, the bottom surface of the large-diameter cylindrical portion 41a located above the small-diameter cylindrical portion 41b is brought into contact with the holding members 44 and 45, so that the combustion catalyst The carrier 41 can be held on the exhaust pipe 15 by the holding members 44 and 45. Further, since the curved portions 44c and 45c are in close contact with the small-diameter cylindrical portion 41b, the combustion medium carrier 41 is prevented from being displaced with respect to the holding members 44 and 45 due to vehicle vibration or the like. Thus, the combustion medium carrier 41 can be positioned at the center in the exhaust pipe axial direction.

  Further, when the surface area of the small-diameter cylindrical portion 41b of the combustion catalyst carrier 41 is increased due to thermal expansion of the combustion catalyst carrier 41, the temperature becomes high as shown in FIGS. 9 (a) to 9 (b). Due to the influence of the combustion catalyst carrier 41, as shown in FIGS. 9A to 9B, the curved portions 44c and 45c expand, so that the displacement due to the thermal expansion of the combustion catalyst carrier 41 is absorbed. be able to.

  In the present embodiment, the combustion catalyst carrier 41 is held by sandwiching the small-diameter cylindrical portion 41b between the curved portions 44c and 45c, so that the curved portions 44c and 45c are fixed to the combustion catalyst carrier 41 by welding or the like. This eliminates the need for the bending portions 44c and 45c to peel off from the small-diameter cylindrical portion 41b. As a result, the combustion catalyst carrier 41 can be stably attached to the exhaust pipe 15 via the holding members 44 and 45, and the reliability of the exhaust gas purification device can be improved. In the present embodiment, the oxidation catalyst 17, the DPF 18, the combustion catalyst 40, and the fuel injection valve 25 constitute an exhaust gas purification device.

(Third embodiment)
In FIG. 10, since the combustion catalyst carrier 41 has the same configuration as that of the second embodiment, a specific description of the combustion catalyst carrier 41 is omitted. The combustion catalyst carrier 41 is held in the exhaust pipe 15 by a triangular holding means 51, and this holding means 51 is composed of a V-shaped holding member 52 and a linear holding member 53. .

  The holding means 51 is configured to have a triangular shape by overlapping the one end portion 53a and the other end portion 53b of the holding member 53 with the one end portion 52a and the other end portion 52b of the holding member 52. 52 between the one end portion 52a and the other end portion 52b, which are both end portions, and between the one end portion 53a and the other end portion 53b, which are both end portions of the holding member 53, are connected to the small diameter cylindrical portion 41b of the combustion catalyst carrier 41. Fitting parts 52c, 52d, 53c to be fitted are formed, and the small diameter cylindrical part 41b is sandwiched by the fitting parts 52c, 52d, 53c, whereby the combustion catalyst carrier 41 is held in the exhaust pipe 15. ing. Further, since the fitting portions 52c, 52d, and 53c are fitted to the small-diameter cylindrical portion 41b so as to contact the small-diameter cylindrical portion 41b of the combustion catalyst carrier 41, the combustion medium carrier 41 is held by the holding member. Therefore, the combustion medium carrier 41 can be positioned at the center in the exhaust pipe axial direction.

  In addition, a gap S is formed between the holding members 52 and 53 and the inner peripheral portion of the exhaust pipe 15, and exhaust gas is circulated through the outer peripheral portion of the combustion catalyst carrier 41 through the gap S. The exhaust resistance can be reduced.

  In the present embodiment, the fitting portions 52c and 52d of the V-shaped holding member 52 are fitted into the small-diameter cylindrical portion 41b, and then the holding member 53 is attached to the one end 52a and the other end 52b of the holding member 52. After the one end 53a and the other end 53b are overlapped and the holding members 52 and 53 are integrated by bonding or the like, the one end 52a and the other end 52b of the holding member 52 and the one end 53a and the other end of the holding member 53 are integrated. 53 b is fixed to the inner peripheral portion of the exhaust pipe 15 by the welded portion 54.

  As described above, in the present embodiment, the holding members 52 and 53 have the fitting portions 52c, 52d, and 53c that are fitted into the small-diameter cylindrical portion 41b of the combustion catalyst carrier 41, and the fitting portions 52c and 52d. 53c, the combustion catalyst carrier 41 is held by sandwiching the small diameter cylindrical portion 41b, so that the bottom surface of the large diameter cylindrical portion 41a located above the small diameter cylindrical portion 41b is held by the holding members 52, 53. The combustion catalyst carrier 41 can be held in the exhaust pipe 15 by the holding members 52 and 53.

  Further, when the combustion catalyst carrier 41 is thermally expanded and the surface area of the small-diameter cylindrical portion 41b of the combustion catalyst carrier 41 is increased, the fitting portions 52c, 52d, By expanding 53c, the displacement due to the thermal expansion of the combustion catalyst carrier 41 can be absorbed.

  Further, in the present embodiment, the combustion catalyst carrier 41 is held by sandwiching the small-diameter cylindrical portion 41b by the fitting portions 52c, 52d, and 53c, so that the fitting portions 52c, 52d, and 53c are burned by welding or the like It is possible to eliminate the need to adhere to the catalyst carrier 41, and the fitting parts 52c, 52d, and 53c do not peel off from the small diameter cylindrical part 41b. As a result, the combustion catalyst carrier 41 can be stably attached to the exhaust pipe 15 via the holding members 52 and 53, and the reliability of the exhaust gas purification device can be improved.

(Fourth embodiment)
12, the holding means 61 is composed of four plate-like members (holding means) 62, 63, 64, 65. As shown in FIG. 13, the height L1 of the plate-like members 62, 63 is as follows. The plate-like members 64 and 65 are formed higher than the height L2. Further, rectangular openings 62a and 63a are formed in the plate-like members 62 and 63. The openings 62a and 63a are slightly larger than the plate thickness of the plate-like members 64 and 65, and the plate-like members. It is formed slightly higher than the heights of 64 and 65.

  Therefore, the plate-like members 64 and 65 can be fitted into the openings 62a and 63a of the plate-like members 62 and 63, and the plate-like members 62 and 63 and the plate-like members 64 and 65 are arranged in a lattice shape. Integrated.

  In addition, fitting parts 62b, 63b, 64a, 65a are formed at approximately the center in the extending direction of the plate-like members 62, 63, 64, 65, and the fitting parts 62b, 63b, 64a, 65a are combusted. The small diameter cylindrical portion 41b of the catalyst carrier 41 is fitted to the small diameter cylindrical portion 41b. At this time, a gap S1 is formed between the fitting portions 62b, 63b, 64a, 65a of the plate-like members 62, 63, 64, 65 and the small-diameter cylindrical portion 41b.

  Further, the one end portions 62c, 63c, 64b, 65b and the other end portions 62d, 63d, 64c, 65c of the plate-like members 62, 63, 64, 65 are fixed to the inner peripheral portion of the exhaust pipe 15 by the welding portion 66. Yes.

  Further, a gap S is formed between the plate-like members 62, 63, 64, 65 and the inner peripheral portion of the exhaust pipe 15, and the exhaust gas is circulated through the outer peripheral portion of the combustion catalyst support 41 through the gap S. Thus, the exhaust resistance of the exhaust gas can be reduced.

  In the present embodiment, after the small-diameter cylindrical portion 41b is sandwiched by the fitting portions 62b and 63b of the plate-like members 62 and 63, the plate-like members 64 and 65 are fitted into the openings 62a and 63a, and the plate-like member is inserted. After the plate-like members 62, 63, 64, 65 are integrated by sandwiching the small-diameter cylindrical portion 41b by the fitting portions 64a, 65a of 64, 65, one end of the plate-like members 62, 63, 64, 65 62 c, 63 c, 64 b, 65 b and the other end portions 62 d, 63 d, 64 c, 65 c are fixed to the inner peripheral portion of the exhaust pipe 15 by the welded portion 66.

  As described above, in the present embodiment, the plate-like members 62, 63, 64, 65 have the fitting portions 62b, 63b, 64a, 65a that are fitted to the small-diameter cylindrical portion 41b of the combustion catalyst support 41. Since the small-diameter cylindrical portion 41b is sandwiched between the fitting portions 62b, 63b, 64a, and 65a, the combustion catalyst carrier 41 is held, so that the large-diameter cylindrical portion located above the small-diameter cylindrical portion 41b. By bringing the bottom surface of 41a into contact with the plate-like members 62, 63, 64, 65, the combustion catalyst carrier 41 can be held in the exhaust pipe 15 by the plate-like members 62, 63, 64, 65.

Further, when the combustion catalyst carrier 41 is at a low temperature, there is a gap between the small diameter cylindrical portion 41b of the combustion catalyst carrier 41 and the fitting portions 62b, 63b, 64a, 65a of the plate-like members 62, 63, 64, 65. Since S1 is formed, when the combustion catalyst carrier 41 is thermally expanded from this state and the surface area of the small diameter cylindrical portion 41b of the combustion catalyst carrier 41 is increased, the small diameter cylindrical portion 41b of the combustion catalyst carrier 41 is By approaching the fitting portions 62b, 63b, 64a, and 65a of the plate-like members 62, 63, 64, and 65, the gap S1 between the small-diameter cylindrical portion 41b and the fitting portions 62b, 63b, 64a, and 65a is reduced. Displacement due to thermal expansion of the small diameter cylindrical portion 41b can be absorbed.
Further, since this gap S1 is provided, even if the plate-like members 62, 63, 64, 65 are thermally expanded so that the plate thickness of the plate-like members 62, 63, 64, 65 increases, the small-diameter cylindrical shape The thermal expansion of the portion 41b can be reliably absorbed.

  Further, in the present embodiment, the combustion catalyst carrier 41 is held by sandwiching the small-diameter cylindrical portion 41b by the fitting portions 62b, 63b, 64a, 65a, so the fitting portions 62b, 63b, 64a, 65a are It is unnecessary to adhere to the combustion catalyst carrier 41 by welding or the like, and there is no situation where the fitting portions 62b, 63b, 64a, 65a are peeled off from the small diameter cylindrical portion 41b. As a result, the combustion catalyst carrier 41 can be stably attached to the exhaust pipe 15 via the plate-like members 62, 63, 64, 65, and the reliability of the exhaust gas purification device can be improved.

(Fifth embodiment)
14 and 15, the configuration of the combustion catalyst carrier 24 is the same as that in the first embodiment, and a specific description thereof will be omitted.

  As shown in FIGS. 14 and 15, the holding members 71 and 72 are configured such that one end portions 71 a and 72 a and the other end portions 71 b and 72 b are fixed to the inner peripheral portion of the exhaust pipe 15 by a welding portion 74. The semicircular curved portions 71c and 72c are formed at substantially the center in the extending direction of the holding members 71 and 72.

  The curved portions 71c and 72c are tapered so as to incline downward in the axial direction of the combustion catalyst carrier 24, and when the holding members 71 and 72 are overlapped, the curved portions 71c and 72c become the combustion catalyst carrier. The diameter is gradually reduced downward in the axial direction of 24.

  In addition, a metal cylindrical mesh member 73 is provided on the upper portions of the holding members 71 and 72, and the mesh member 73 is disposed above the curved portions 71c and 72c so as to cover the combustion catalyst carrier 24 from above. As a result, the combustion catalyst carrier 24 is prevented from coming out of the curved portions 71c and 72c due to severe vibrations of the vehicle.

  In addition, a gap S is formed between the holding members 71 and 72 and the inner peripheral portion of the exhaust pipe 15, and exhaust gas is allowed to flow through the outer peripheral portion of the combustion catalyst support 24 through the gap S. The exhaust resistance can be reduced.

  In order to hold the combustion catalyst carrier 24 in the exhaust pipe 15 by the holding members 71 and 72 having such a configuration, the one end portions 71a and 72a of the holding members 71 and 72 and the holding members 71 and 72 face each other. After the other end portions 71b and 72b are fixed to the inner peripheral portion of the exhaust pipe 15 by welding, the combustion catalyst carrier 24 is fitted to the curved portions 71c and 72c.

  At this time, the combustion catalyst carrier 24 moves downward due to its own weight G, and the combustion catalyst carrier 24 moves to the curved portions 71c and 72c at a portion where the diameter of the combustion catalyst carrier 24 and the inner diameters of the curved portions 71c and 72c coincide. The fitting catalyst is restricted from moving downward, and the combustion catalyst carrier 24 is supported by the exhaust pipe 15 via the holding members 71 and 72.

  In the present embodiment, when the holding members 71 and 72 are overlapped, the curved portions 71c and 72c are gradually reduced in diameter toward the lower side in the axial direction of the combustion catalyst carrier 24. When the combustion catalyst carrier 24 is thermally expanded during regeneration and the surface area of the combustion catalyst carrier 24 is increased, the combustion catalyst carrier 24 follows the tapered surfaces of the curved portions 71c and 72c from the state shown in FIG. 16 (b), the displacement due to the thermal expansion of the combustion catalyst carrier 24 can be absorbed.

  Further, when the combustion catalyst carrier 24 becomes low in temperature, the combustion catalyst carrier 24 is reduced, so that the combustion catalyst carrier 24 is changed from the state shown in FIG. As shown, the combustion catalyst carrier 24 moves downward along the tapered surfaces of the curved portions 71c, 72c, and the combustion catalyst carrier 24 is curved at the portions 71c, 72c where the diameter of the combustion catalyst carrier 24 and the inner diameter of the curved portions 71c, 72c coincide. It is restricted that it fits in 72c and moves downward.

  In the present embodiment, since the combustion catalyst carrier 24 is held so as to sandwich the combustion catalyst carrier 24 between the curved portions 71c and 72c, the curved catalyst portions 24c and 72c are welded to the combustion catalyst carrier 24. Therefore, the curved portions 71c and 72c are not peeled off from the combustion catalyst carrier 24. As a result, the combustion catalyst carrier 24 can be stably attached to the exhaust pipe 15 via the holding members 71 and 72, and the reliability of the exhaust gas purification device can be improved.

(Sixth embodiment)
17 and 18, the configuration of the combustion catalyst carrier 24 is the same as that of the first embodiment, and a specific description thereof will be omitted.

  As shown in FIGS. 17 and 18, the holding members 81 and 82 include bottom portions 81a and 82a on which the combustion catalyst carrier 24 is placed, and peripheral wall portions 81b and 82b extending upward from the bottom portions 81a and 82a. I have.

  A pair of stopper portions 81c and 82c projecting toward the combustion catalyst carrier 24 are formed on the inner peripheral portions of the peripheral wall portions 81b and 82b, and the peripheral wall portions 81b and 82b are formed on the upper ends of the peripheral wall portions 81b and 82b. Bending portions 81d and 82d that are bent from 82b toward the combustion catalyst carrier 24 are formed, and the combustion catalyst carrier 24 is excessively moved in the vertical direction and the direction perpendicular to the vertical direction due to severe vibration of the vehicle or the like. Occasionally, the combustion catalyst carrier 24 abuts against the stopper portions 81c and 82c and the bent portions 81d and 82d, so that the combustion catalyst carrier 24 can be prevented from coming out of the holding members 81 and 82.

  A plurality of attachment pieces 81 e and 82 e are provided on the outer peripheral portions of the peripheral wall portions 81 b and 82 b, and the attachment pieces 81 e and 82 e are fixed to the inner peripheral portion of the exhaust pipe 15 by the welding portion 83. Therefore, a gap S can be formed between the peripheral wall portions 81b, 82b of the holding members 81, 82 and the inner peripheral portion of the exhaust pipe 15, and the exhaust gas is passed through the gap S to the outer peripheral portion of the combustion catalyst carrier 24. The exhaust resistance of the exhaust gas can be reduced by allowing the exhaust gas to flow through.

  In the present embodiment, the attachment piece 81 e of the holding member 81 is fixed to the inner peripheral portion of the exhaust pipe 15 by the welding portion 83, and then the combustion catalyst carrier 24 is attached to the holding member 81. Next, the holding member 82 is made to face the holding member 81 so as to hold the combustion catalyst carrier 24, and then the attachment piece 82e is fixed to the inner peripheral portion of the exhaust pipe 15 by the welded portion 83, whereby the holding member 81, The combustion catalyst carrier 24 is held in the exhaust pipe 15 by 82.

  When the combustion catalyst carrier 24 is at a low temperature from the state shown in FIG. 18A, a constant gap L3 is formed between the combustion catalyst carrier 24 and the peripheral wall portions 81b and 82b. When the combustion catalyst carrier 24 is thermally expanded from this state and the surface area of the combustion catalyst carrier 24 is increased, the gap L4 between the combustion catalyst carrier 24 and the peripheral wall portions 81b and 82b becomes small as shown in FIG. Thus, the displacement due to the thermal expansion of the combustion catalyst carrier 24 can be absorbed.

  In the present embodiment, since the combustion catalyst carrier 24 is placed on the bottom portions 81a and 82a of the holding members 81 and 82, the holding members 81 and 82 hold the combustion catalyst carrier 24. It is unnecessary to fix the 81a, 82a to the combustion catalyst carrier 24 by welding or the like, and the situation where the bottom portions 81a, 82a are peeled off from the combustion catalyst carrier 24 does not occur. As a result, the combustion catalyst carrier 24 can be stably attached to the exhaust pipe 15 via the holding members 81 and 82, and the reliability of the exhaust gas purification device can be improved.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the exhaust gas purification apparatus according to the present invention has the effect of providing a highly reliable exhaust gas purification apparatus that can stably hold the combustion catalyst carrier in the exhaust pipe by the holding member. It is useful as an exhaust gas purifying apparatus having a holding means for holding a combustion catalyst carrier having a catalyst for burning fuel and holding it in an exhaust pipe.

DESCRIPTION OF SYMBOLS 11 Internal combustion engine 23 Combustion catalyst 24 Combustion catalyst support body 26 Holding means 27 Plate-like member 27A Base end part 27B Front end part 27a Bottom face 27b One side surface 31 Exhaust gas purifier 40 Combustion catalyst 41 Combustion catalyst support body 41a, 41c Large diameter cylindrical shape Portion 41b Small diameter cylindrical portion 44, 45 Holding member (holding means)
44a, 45a One end 44b, 45b The other end 44c, 45c Bending part (fitting part)
51 holding means 52, 53 holding members 52a, 53a one end 52b, 53b other ends 52c, 52d, 53c fitting parts 62, 63, 64, 65 plate-like members (holding means)
62b, 63b, 64a, 65a Fitting portion 62c, 63c, 64b, 65b One end 62d, 63d, 64c, 65c The other end 71, 72 Holding member (holding means)
71a, 72a One end 71b, 72b The other end 71c, 72c Bending part 81, 82 Holding member (holding means)

Claims (2)

A purifying means disposed in an exhaust pipe of the internal combustion engine for purifying exhaust gas discharged from the internal combustion engine; and disposed in the exhaust pipe upstream of the purifying means in the exhaust direction of the exhaust gas; An exhaust gas purification apparatus comprising a cylindrical combustion catalyst carrier for supporting a burning catalyst, and a fuel supply means that is located upstream of the combustion catalyst in the exhaust gas exhaust direction and supplies fuel into the exhaust pipe In
Holding means for holding the combustion catalyst carrier in the exhaust pipe such that a gap is defined between the periphery of the combustion catalyst carrier and the inner periphery of the exhaust pipe;
The holding means has a base end portion whose bottom surface is fixed to the inner peripheral portion of the exhaust pipe, and a side surface that protrudes from the base end portion toward the combustion catalyst carrier and is substantially orthogonal to the bottom surface. A tip portion fixed to the outer periphery of the carrier, and is composed of a plurality of plate-like members extending in the extending direction of the combustion catalyst carrier,
By holding the combustion catalyst carrier so that the plurality of plate-like members surround the combustion catalyst carrier around the center axis of the combustion catalyst carrier, displacement due to thermal expansion of the combustion catalyst carrier is reduced. An exhaust gas purifying device characterized by absorbing . A purifying means disposed in an exhaust pipe of the internal combustion engine for purifying exhaust gas discharged from the internal combustion engine; and disposed in the exhaust pipe upstream of the purifying means in the exhaust direction of the exhaust gas; An exhaust gas purification apparatus comprising a cylindrical combustion catalyst carrier for supporting a burning catalyst, and a fuel supply means that is located upstream of the combustion catalyst in the exhaust gas exhaust direction and supplies fuel into the exhaust pipe In
Holding means for holding the combustion catalyst carrier in the exhaust pipe such that a gap is defined between the periphery of the combustion catalyst carrier and the inner periphery of the exhaust pipe;
The cylindrical combustion catalyst carrier is integrally formed with a large-diameter cylindrical portion and a small-diameter cylindrical portion that is located between the large-diameter cylindrical portion and smaller in diameter than the large-diameter cylindrical portion. ,
The holding means has a plurality of holding members having both end portions fixed to the inner peripheral portion of the exhaust pipe, and a fitting portion fitted between the both end portions and fitted into the small-diameter cylindrical portion. by holding the combustion catalyst carrier so as to sandwich the small-diameter cylindrical portion by engagement portion, exhaust gas purification device shall be the feature to absorb the displacement due to thermal expansion of the combustion catalyst carrier.

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