JP6932231B1 - Exhaust treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust treatment device capable of suppressing an increase in body temperature and suppressing generation of radiated sound. An exhaust treatment device 100 has an exhaust treatment unit 10 that has a catalyst 1 for treating the exhaust gas G and guides the exhaust gas G to flow through the catalyst 1, and a cover 20 that covers the outer periphery of the exhaust gas treatment unit 10. And. The cover 20 includes an inner plate 21 provided so as to face the outer periphery of the exhaust treatment unit 10, a fibrous material layer 22 provided on the outer periphery of the inner plate 21, and an outer plate 23 covering the outer periphery of the fibrous material layer 22. Between the cover 20 and the exhaust processing unit 10, the inflow port 40 through which air flows in, the flow path 41 through which the air flowing in from the inflow port 40 passes, and the air passing through the flow path 41 flow out. The outlet 42 and the outlet 42 are formed. [Selection diagram] Fig. 1

Description

The present invention relates to an exhaust treatment device.

Patent Document 1 describes a heat shield holding material having a U-shaped cross section and covering a part of the outer surface of a curved surface portion and a flat surface portion of a metal carrier, and a heat shield plate further covering the outer surface of the heat shield holding material. And, a catalytic converter having is disclosed. In this catalytic converter, most of the flat surface portion of the metal carrier is not covered with the heat shield holding material, thereby promoting heat dissipation from the flat surface portion and lowering the temperature of the metal carrier.

Japanese Unexamined Patent Publication No. 2003-286838

By the way, the exhaust gas discharged from the engine and flowing into the catalytic converter becomes even higher in temperature when the combustion efficiency of the engine is improved. If hot exhaust gas flows into the catalytic converter, the catalytic converter may overheat.

Further, the catalytic converter is required to suppress the radiated sound generated by the vibration transmitted from the engine.

The present invention has been made in view of the above points, and provides an exhaust treatment device capable of suppressing an increase in the temperature of the main body, suppressing the generation of radiated sound, and preventing heat damage to parts surrounding the main body. The purpose is.

According to an aspect of the present invention, the exhaust treatment device includes an exhaust treatment component that treats the exhaust gas and guides the exhaust gas to flow to the exhaust treatment component, and an outer periphery of the exhaust treatment section. The cover includes an inner plate provided so as to face the outer periphery of the exhaust treatment unit, a mat provided on the outer periphery of the inner plate, and an outer plate covering the outer periphery of the mat. Between the cover and the exhaust treatment unit, an inflow port through which air flows in, a flow path through which air flowing in from the inflow port passes, and a flow path through which air passing through the flow path flows out. It is characterized in that an outlet is formed.

According to another aspect of the present invention, the exhaust treatment apparatus includes an exhaust treatment component that treats exhaust gas at 950 ° C. or higher and guides the exhaust gas to flow to the exhaust treatment component, and the exhaust gas treatment unit described above. A cover that covers the outer periphery of the exhaust treatment unit is provided, and the cover covers an inner plate provided so as to face the outer circumference of the exhaust treatment unit, a mat provided on the outer periphery of the inner plate, and an outer circumference of the mat. It has an outer plate to cover, and between the cover and the exhaust treatment unit, an inflow port through which air flows in, a flow path through which air flowing in from the inflow port passes, and the flow path passed through the flow path. An outlet for air to flow out is formed, the thickness of the mat is 3 to 20 mm, and the clearance dimension between the exhaust treatment unit and the cover in the flow path is 3 to 20 mm. ..

In the above aspect, by forming a flow path through which air flows between the cover and the exhaust treatment section, the heat of the exhaust treatment section can be released to the air in the flow path and the temperature rise of the exhaust treatment section can be suppressed. can. Further, by providing a mat between the inner plate and the outer plate, it is possible to suppress the vibration of the outer plate, suppress the generation of radiated sound from the outer plate, and transfer heat from the inner plate to the outer plate. Suppress. Therefore, it is possible to suppress an increase in the temperature of the main body, suppress the generation of radiated sound, and prevent heat damage to the parts surrounding the main body.

FIG. 1 is a schematic cross-sectional view of an exhaust treatment device according to the first embodiment of the present invention. FIG. 2A is a schematic view of a cross section of IIA-IIA of FIG. FIG. 2B is an enlarged view of the IIB portion of FIG. 2A. FIG. 3 is a perspective view of the exhaust treatment device according to the second embodiment of the present invention. FIG. 4 is a perspective view of the exhaust treatment device according to the second embodiment of the present invention in a direction different from that of FIG. FIG. 5 is a sectional view taken along line VV of FIG. FIG. 6 is a cross-sectional view corresponding to FIG. 5 of the exhaust treatment device according to the modified example of the second embodiment of the present invention. FIG. 7 is a diagram for explaining the arrangement of the exhaust treatment device and the inflow of air into the exhaust treatment device according to the second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view of the exhaust treatment device according to the third embodiment of the present invention. FIG. 9 is an enlarged schematic view of a cross section of the cover of the exhaust treatment device according to the first modification. FIG. 10 is an enlarged schematic view of a cross section of the cover of the exhaust treatment device according to the second modification. FIG. 11 is an enlarged schematic view of a cross section of the cover of the exhaust treatment device according to the third modification.

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

(First Embodiment)
Hereinafter, the exhaust treatment device 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 2B. FIG. 1 is a schematic cross-sectional view of the exhaust treatment device 100. FIG. 2A is a schematic view of a cross section of IIA-IIA of FIG. FIG. 2B is an enlarged view of the IIB portion of FIG. 2A.

First, the configuration of the exhaust treatment device 100 will be described.

The exhaust treatment device 100, for example, is mounted on a vehicle and oxidizes hydrocarbons and carbon monoxide contained in exhaust gas G discharged from an engine (not shown) to carbon dioxide and water, and nitrogen oxides. And removes fine particulate matter to purify the exhaust gas G.

As shown in FIGS. 1 and 2A, the exhaust treatment device 100 has a catalyst 1 as an exhaust treatment component for treating the exhaust gas G at 950 ° C. or higher, and guides the exhaust gas G to flow through the catalyst 1. A processing unit 10 and a cover 20 that covers the outer periphery of the exhaust gas processing unit 10 are provided.

The exhaust treatment unit 10 has a catalyst 1 and a case 11.

The catalyst 1 is composed of a columnar honeycomb structure. The outer peripheral surface of the catalyst 1 is fitted to the inner circumference of the case 11 via the cushioning material 12.

As shown in FIG. 1, the case 11 is a tubular member having tapered ends. An entrance side opening 11a opens at one end of the case 11. An outlet side opening 11b opens at the other end of the case 11.

The inlet side opening 11a is connected to the exhaust manifold (not shown) of the engine. As a result, the exhaust gas G discharged from the engine passes through the exhaust manifold and the inlet side opening 11a and flows into the case 11. That is, the end portion of the case 11 on the inlet side opening 11a side is the end portion of the exhaust gas processing unit 10 on the upstream side in the exhaust gas flow direction.

The outlet side opening 11b is connected to an exhaust pipe (not shown). As a result, the exhaust gas G that has passed through the case 11 flows into the exhaust pipe. That is, the end portion of the case 11 on the outlet side opening 11b side is the end portion of the exhaust gas processing unit 10 on the downstream side in the exhaust gas flow direction.

The cover 20 is a tubular member that covers the outer periphery of the exhaust processing unit 10. The cover 20 is provided with a predetermined distance from the outer circumference of the exhaust processing unit 10. The cover 20 has an inner plate 21 provided so as to face the outer periphery of the exhaust treatment unit 10, a fibrous material layer 22 as a mat provided on the outer periphery of the inner plate 21, and an outer plate 23 covering the outside of the fibrous material layer 22. And have.

As shown in FIGS. 2A and 2B, the inner plate 21 has a first inner plate 21a and a second inner plate 21b that are divided in the circumferential direction. Similarly, the outer plate 23 has a first outer plate 23a and a second outer plate 23b that are divided in the circumferential direction.

Flange portions 21c and 21d are formed at one end and the other end of the first inner plate 21a. Flange portions 21e and 21f are formed at one end and the other end of the second inner plate 21b. Flange portions 23c and 23d are formed at one end and the other end of the first outer plate 23a. Flange portions 23e and 23f are formed at one end and the other end of the second outer plate 23b.

The flange portion 23c of the first outer plate 23a is attached to the outer peripheral side of the flange portion 21c of the first inner plate 21a, and the flange portion 23d of the first outer plate 23a is attached to the outer peripheral side of the flange portion 21d of the first inner plate 21a. As a result, a space is formed between the first inner plate 21a and the first outer plate 23a. By compressing and filling this space with a fibrous substance having heat resistance (silica fiber in this embodiment), a fibrous material layer 22a is provided on the outer periphery of the first inner plate 21a.

Similarly, the space between the second inner plate 21b and the second outer plate 23b is compression-filled with a heat-resistant fibrous material to provide the fibrous material layer 22b on the outer periphery of the second inner plate 21b. The thickness X (see FIG. 1) of the fibrous material layers 22a and 22b is 3 to 20 mm.

When the thickness X of the fibrous material layers 22a and 22b is smaller than 3 mm, the effect on the function due to insufficient heat insulating performance and dimensional variation becomes large. On the other hand, if the thickness X of the fibrous material layers 22a and 22b is larger than 20 mm, there is a concern that the cost will increase and the mountability will deteriorate.

In particular, by setting the lower limit of the thickness X to 5 mm, the upper limit to 15 mm, and the thickness X of the fibrous material layers 22a and 22b to 5 to 15 mm, it is possible to suppress the influence on the function and the deterioration of the mountability due to the variation in dimensions. However, it is possible to reduce the surface temperature of the cover 20 and reduce the cost at the same time. The optimum value of the thickness X of the fiber material layers 22a and 22b is 10 mm.

As shown in FIGS. 2A and 2B, the exhaust treatment device 100 includes a bracket 30 for holding the cover 20 in the exhaust treatment unit 10. The bracket 30 is a member formed in a substantially L shape.

As shown in FIG. 2B, one end 30a of the bracket 30 is attached to the outer periphery of the case 11 of the exhaust processing unit 10. The other end 30b of the bracket 30 is attached while one end (flange portion 21c) of the first inner plate 21a and one end (flange portion 21e) of the second inner plate 21b are abutted against each other.

Similarly, one end 30a of the bracket 30 is attached to the outer periphery of the case 11, and the other end 30b is the other end of the first inner plate 21a (flange portion 21d) and the other end of the second inner plate 21b (flange portion 21f). It is installed in between. As a result, the cover 20 is held by the exhaust processing unit 10 via the bracket 30.

As shown in FIG. 1, by providing the cover 20 at a distance from the outer periphery of the exhaust treatment unit 10, an inflow port 40 through which air flows and an inflow port 40 are provided between the exhaust treatment unit 10 and the cover 20. A flow path 41 through which the air flowing in from the flow path 41 passes and an outlet 42 through which the air passing through the flow path 41 flows out are formed.

The inflow port 40 opens so as to face the flow of external air. In the present embodiment, the inflow port 40 is located on the front side of the vehicle. The outlet 42 is located on the rear side of the vehicle.

The flow path 41 is formed from the inlet side opening 11a side of the case 11 to the outlet side opening 11b side. That is, the flow path 41 is formed from the end portion of the exhaust gas processing unit 10 on the upstream side in the exhaust gas flow direction to the end portion on the downstream side in the exhaust gas flow direction.

The flow path 41 is surrounded by an outer peripheral surface 11g of the case 11 and an inner peripheral surface 21g of the inner plate 21 facing the case 11. The flow path 41 is covered with the fibrous material layers 22a and 22b. Further, in order to suppress the transfer of radiant heat from the inner plate 21 to the outer plate 23, it is desirable that the entire circumference of the flow path 41 is covered with the fibrous material layers 22a and 22b.

Here, if the gap dimension (height of the flow path 41) Y between the exhaust treatment section 10 and the cover 20 is smaller than 3 mm, the exhaust treatment section 10 and the cover 20 may interfere with each other due to dimensional variation or vibration input. There is. On the other hand, if the gap dimension Y is larger than 20 mm, there is a concern that the mountability may be deteriorated and the air flow velocity in the flow path 41 may be lowered.

In particular, by setting the gap dimension Y to 3 to 10 mm, it is possible to improve the mountability and secure the flow velocity of the air required for cooling the catalyst 1. The optimum value of the gap dimension Y is 6 mm.

Further, in the exhaust treatment device 100, when treating the exhaust gas G at 950 ° C. or higher, the condition of the thickness X of the fibrous material layers 22a and 22b and the condition of the flow path width Y are satisfied at the same time. It is desirable to do. This simultaneously cools the catalyst 1 during running and suppresses the surface temperature of the cover 20 after the vehicle is stopped, while suppressing cost increase and deterioration of mountability when treating exhaust gas G at 950 ° C. or higher. Because it can be achieved.

In the exhaust treatment device 100, by simultaneously satisfying the condition of the thickness X of the fibrous material layers 22a and 22b and the condition of the flow path width Y, the exhaust gas at a high temperature of 1000 ° C. or higher or 1100 ° C. or higher is exhausted. It is also fully applicable to an exhaust gas treatment device that treats gas G.

As shown in FIGS. 1 and 2A, a plurality of mesh members 50 are provided in the flow path 41. The mesh member 50 is a member having a mesh structure that does not block the air flow in the flow path 41. The mesh member 50 is provided so that the inner peripheral side is in contact with the outer periphery of the exhaust processing unit 10 and the outer peripheral side is in contact with the inner plate 21 (first inner plate 21a or second inner plate 21b). The mesh member 50 damps the vibration of the entire cover 20 when the exhaust processing unit 10 vibrates and the cover 20 vibrates via the bracket 30.

The number of mesh members 50 can be appropriately changed according to the size of the exhaust treatment device 100, the size of the catalyst 1, the number of brackets 30, and the like. For example, when the number of brackets 30 is one, a plurality of mesh members 50 are provided on the side of the flow path 41 where the brackets 30 are not provided (the side facing the brackets 30). In this case, the cover 20 is held by the exhaust treatment device 100 via the bracket 30 and the mesh member 50.

Next, the operation of the exhaust treatment device 100 will be described.

The high-temperature exhaust gas G discharged from the engine flows into the exhaust processing unit 10 (case 11) from the inlet side opening 11a. The exhaust gas processing unit 10 (case 11) guides the exhaust gas G so that the exhaust gas G flows through the catalyst 1. The catalyst 1 purifies the exhaust gas G by oxidizing hydrocarbons and carbon monoxide contained in the exhaust gas G to carbon dioxide and water, reducing nitrogen oxides and removing fine particulate matter. The outlet side opening 11b guides the exhaust gas G purified by the catalyst 1 to the exhaust pipe.

At this time, the exhaust processing unit 10 becomes hot due to the flow of the high-temperature exhaust gas G. Therefore, if the combustion efficiency of the engine is improved and the higher temperature exhaust gas G flows through the exhaust treatment unit 10, the entire exhaust treatment device 100 may overheat.

On the other hand, in the exhaust treatment device 100 of the present embodiment, a flow path 41 through which air flows is formed between the exhaust treatment unit 10 and the cover 20. As a result, the exhaust treatment unit 10 whose temperature has been raised by the exhaust gas G can release heat to the air flowing through the flow path 41 (dotted line arrow A1 in FIG. 1) to suppress an increase in the temperature of the main body.

Further, the flow path 41 is widely formed from the end portion of the exhaust gas processing unit 10 on the upstream side in the exhaust gas flow direction to the end portion on the downstream side in the exhaust gas flow direction. That is, in the exhaust treatment device 100, a large heat exchange area between the exhaust gas G flowing through the exhaust treatment unit 10 and the air flowing through the flow path 41 is provided. Therefore, heat can be easily released from the exhaust treatment unit 10, and an increase in the temperature of the main body of the exhaust treatment unit 10 can be suppressed.

Further, the inflow port 40 is opened so as to face the air flow so that the air can be easily taken in. That is, air easily flows from the inflow port 40 into the flow path 41, and the flow rate of air in the flow path 41 increases. Therefore, the exhaust processing unit 10 can release more heat, and it is possible to suppress an increase in the temperature of the main body of the exhaust processing unit 10.

Since the inflow port 40 is located on the front side of the vehicle and the outflow port 42 is located on the rear side of the vehicle, air can easily flow into the flow path 41, and the flow rate of air in the flow path 41 increases. Therefore, the exhaust processing unit 10 can release more heat, and it is possible to suppress an increase in the temperature of the main body of the exhaust processing unit 10.

Further, vibration is transmitted from the engine to the exhaust treatment device 100. When the vibration is transmitted, the exhaust treatment device 100 may generate a radiated sound from the exhaust treatment unit 10 and the outer plate 23. Therefore, the exhaust treatment device 100 is required to suppress the radiated sound generated by the vibration.

On the other hand, in the present embodiment, the fibrous material layer 22 (22a, 22b) compression-filled with the fibrous material is provided between the inner plate 21 (21a, 21b) and the outer plate 23 (23a, 23b). As a result, the inner plates 21 (21a, 21b) and the outer plates 23 (23a, 23b) are in a state of receiving (pressing) a repulsive force from the fibrous material layer 22, and even if vibration is transmitted, it becomes difficult to vibrate.

Further, by providing the fibrous material layer 22 (22a, 22b) between the inner plate 21 (21a, 21b) and the outer plate 23 (23a, 23b), the vibration of the inner plate 21 (21a, 21b) is outside. It becomes difficult to transmit to the plate 23 (23a, 23b). As a result, the vibration of the outer plate 23 is suppressed, so that the generation of radiated sound from the outer plate 23 can be suppressed.

Further, in the present embodiment, the other end 30b of the bracket 30 that holds the cover 20 in the exhaust processing unit 10 comes into contact with the first inner plate 21a and the second inner plate 21b. That is, the bracket 30 is not brought into contact with the outer plate 23. In this way, by adopting a structure in which the vibration transmitted from the engine to the bracket 30 via the exhaust processing unit 10 is transmitted to the inner plate 21, the transmission of the vibration from the outer plate 23 to the outer plate 23 is suppressed. The generation of radiated sound can be suppressed.

By the way, when the exhaust processing unit 10 becomes hot due to the flow of the high-temperature exhaust gas G, the inner plate 21 becomes hot due to the radiant heat from the exhaust processing unit 10 (case 11).

Here, if the fibrous material layer 22 is not provided between the inner plate 21 and the outer plate 23, the outer plate 23 may become hot due to the radiant heat of the hot inner plate 21.

On the other hand, in the exhaust treatment device 100 of the present embodiment, the transfer of radiant heat from the inner plate 21 to the outer plate 23 is suppressed by providing the fibrous material layer 22 between the inner plate 21 and the outer plate 23. .. As a result, it is possible to prevent the outer plate 23 from becoming hot, improve the heat insulating performance of the exhaust treatment device 100, and prevent heat damage to the parts surrounding the main body.

(Second embodiment)
Hereinafter, the exhaust treatment device 200 according to the second embodiment of the present invention will be described with reference to FIGS. 3 to 7. FIG. 3 is a perspective view of the exhaust treatment device 200. FIG. 4 is a perspective view of the exhaust treatment device 200 in a direction different from that of FIG. FIG. 5 is a sectional view taken along line VV of FIG. FIG. 6 is a cross-sectional view corresponding to FIG. 5 of the exhaust treatment device 200 according to the modified example of the second embodiment of the present invention. FIG. 7 is a diagram for explaining the arrangement of the exhaust treatment device 200 and the inflow of air into the exhaust treatment device 200.

First, the configuration of the exhaust treatment device 200 will be described.

As shown in FIGS. 3 to 5, the exhaust treatment device 200 includes a catalyst 1 as an exhaust treatment component for treating the exhaust gas G, and an exhaust treatment unit 210 that guides the exhaust gas G to flow through the catalyst 1. A cover 220 that covers the outer periphery of the exhaust processing unit 210 is provided.

As shown in FIG. 5, the exhaust treatment unit 210 includes a catalyst 1 and a case 211.

Similar to the exhaust treatment device 100, the outer peripheral surface of the catalyst 1 is fitted to the inner circumference of the case 211 via a cushioning material (not shown).

The case 211 is a substantially tubular member in which one end and the other end are bent. An inlet side opening 211a opens at one end of the case 211. An outlet side opening 211b opens at the other end of the case 211.

As shown in FIG. 7, the inlet side opening 211a is connected to the exhaust manifold (not shown) of the engine via the turbocharger 93. As a result, the exhaust gas G discharged from the engine passes through the exhaust manifold, the turbocharger 93, and the inlet side opening 211a, and flows into the case 211. That is, the end portion of the case 211 on the inlet side opening 211a side is the end portion of the exhaust gas processing unit 10 on the upstream side in the exhaust gas G flow direction.

The outlet side opening 211b is connected to the exhaust pipe 95. As a result, the exhaust gas G that has passed through the case 211 flows into the exhaust pipe 95. That is, the end portion of the case 211 on the outlet side opening 211b side is the end portion of the exhaust gas processing unit 210 on the downstream side in the exhaust gas G flow direction.

As shown in FIGS. 3 to 5, boss portions 25 and 26 for communicating the inside and the outside of the case 211 are provided on the upstream side of the exhaust gas processing section 210 in the exhaust gas G flow direction. A temperature sensor (not shown) for detecting the temperature of the exhaust gas G is inserted into the boss portion 25. An oxygen concentration sensor (not shown) for detecting the oxygen concentration of the exhaust gas G is inserted into the boss portion 26.

As shown in FIGS. 3 and 4, a boss portion 27 for communicating the inside and the outside of the case 211 is provided on the downstream side of the exhaust gas processing portion 210 in the exhaust gas G flow direction. An oxygen concentration sensor (not shown) for detecting the oxygen concentration of the downstream exhaust gas G is inserted into the boss portion 27.

As shown in FIG. 5, the cover 220 is a substantially tubular member that covers the outer periphery of the exhaust processing unit 210. The cover 220 is provided with a predetermined distance from the outer periphery of the exhaust processing unit 210. The cover 220 includes an inner plate 221 provided so as to face the outer periphery of the exhaust treatment unit 210, a fibrous material layer 222 provided on the outer periphery of the inner plate 221 and an outer plate 223 covering the outside of the fibrous material layer 222. Have.

The inner plate 221 has a first inner plate 221a, a second inner plate 221b, a third inner plate 221g, and a fourth inner plate 221h which are divided in the circumferential direction. Similarly, the outer plate 223 has a first outer plate 223a, a second outer plate 223b, a third outer plate 223g, and a fourth outer plate 223h which are divided in the circumferential direction.

As shown in FIGS. 4 and 5, the first inner plate 221a, the first outer plate 223a, the second inner plate 221b, and the second outer plate 223b are formed in a shape in which the boss portions 25 and 26 are exposed to the outside. NS. That is, the cover 220 is formed so that a part of the temperature sensor inserted into the boss portion 25 and a part of the oxygen concentration sensor inserted into the boss portion 26 are exposed to the outside.

The third inner plate 221 g and the third outer plate 223 g are formed in a shape in which the boss portion 27 is exposed to the outside (see FIGS. 3 and 4).

As shown in FIGS. 3 to 5, the third inner plate 221 g, the third outer plate 223 g, the fourth inner plate 221h, and the fourth outer plate 223h are beaded. As a result, the bead 224 is provided on the cover 220. A plurality of bead 224s are formed in the flow direction of the exhaust gas G (or the flow direction of the flow path 241 described later, the dotted arrow A2 in FIG. 5) (see FIG. 5). The shape of the bead 224 can be appropriately changed according to the strength required for the exhaust treatment device 200 and the flow path area of the flow path 241 described later. In this embodiment, the beads 224 are provided so as to project evenly over the entire circumference of the cover 220.

As shown in FIGS. 3 and 4, flange portions 221c and 221d are formed at one end and the other end of the first inner plate 221a. Flange portions 221e and 221f are formed at one end and the other end of the second inner plate 221b. Flange portions 221i and 221j are formed at one end and the other end of the third inner plate 221g. Flange portions 221k and 221l are formed at one end and the other end of the fourth inner plate 221h.

Flange portions 223c and 223d are formed at one end and the other end of the first outer plate 223a. Flange portions 223e and 223f are formed at one end and the other end of the second outer plate 223b. Flange portions 223i and 223j are formed at one end and the other end of the third outer plate 223g. Flange portions 223k and 223l are formed at one end and the other end of the fourth outer plate 223h.

The flange portion 223c of the first outer plate 223a is attached to the outer peripheral side of the flange portion 221c of the first inner plate 221a, and the flange portion 223d of the first outer plate 223a is attached to the outer peripheral side of the flange portion 221d of the first inner plate 221a. As a result, a space is formed between the first inner plate 221a and the first outer plate 223a (see FIG. 5). By compressing and filling this space with a fibrous substance having heat resistance, a fibrous substance layer 222a is provided on the outer periphery of the first inner plate 221a.

Similarly, the space between the second inner plate 221b and the second outer plate 223b, the space between the third inner plate 221g and the third outer plate 223g, and the fourth inner plate 221h and the fourth outer plate 223h. The space between them is compression-filled with a heat-resistant fibrous material. As a result, the fibrous material layer 222b is formed on the outer periphery of the second inner plate 221b, the fibrous material layer 222g is formed on the outer periphery of the third inner plate 221g, and the fibrous material layer 222h is formed on the outer periphery of the fourth inner plate 221h. (See Fig. 5).

As shown in FIG. 5, the thickness T1 of the fibrous material layers 222a and 222b on the upstream side in the exhaust gas G flow direction (the inflow port 240 side described later) is the downstream side in the exhaust gas G flow direction (outlet 242 side described later). The fibrous material layer of 222g and 222h is formed to be thicker than T2.

Further, in the exhaust treatment device 200, the repulsive force (pressing pressure) acting on the inner plate 221 (221a, 221b, 221g, and 221h) and the outer plate 223 (223a, 223b, 223g, and 223h) from the fiber material layer 222 is applied. The filling density of the fibrous material in the fibrous material layers 222a and 222b on the upstream side in the exhaust gas G flow direction (the inflow port 240 side described later) and the downstream side in the exhaust gas G flow direction (outlet 242 side described later) so as to be the same. ), The packing density of the fibrous material in 222g and 222h is made the same. The term "same" includes not only the case of being completely the same, but also the case of being substantially the same as a whole even if there are variations depending on the position, for example, the packing densities are partially different.

Similar to the exhaust treatment device 100, the exhaust treatment device 200 includes a bracket 30 for holding the cover 220 in the exhaust treatment unit 210 (see FIGS. 3 and 4). Since the structure and holding state of the bracket 30 are the same as those of the exhaust treatment device 100, the description thereof will be omitted here.

As shown in FIGS. 3 and 5, by providing the cover 220 at a distance from the outer periphery of the exhaust treatment unit 210, an inflow port 240 through which air flows in is provided between the exhaust treatment unit 210 and the cover 220. A flow path 241 through which the air flowing in from the inflow port 240 passes and an outflow port 242 through which the air passing through the flow path 241 flows out are formed.

As shown in FIG. 5, the inflow port 240 is formed so that the flow path cross-sectional area (opening area) at the position C1 is larger than the flow path cross-sectional area at the position C2 of the flow path 241. This facilitates the flow of external air from the inflow port 240 to the flow path 241.

The outlet 242 is formed so that the flow path cross-sectional area (opening area) at position C3 is larger than the flow path cross-sectional area at position C2 of the flow path 241. As a result, the ventilation resistance of the flow path 241 is reduced, and air can easily flow in the flow path 241.

The flow path cross-sectional area at at least one position C1 (or C3) of the inflow port 240 and the outflow port 242 is formed larger than the flow path cross-sectional area at the position C2 of the flow path 241, or the inflow port 240 and the flow path are formed. Whether or not the flow path cross-sectional area at the positions C1 and C3 of the outlets 242 is formed larger than the flow path cross-sectional area at the position C2 of the flow path 241 is appropriately selected depending on the size and shape of the exhaust treatment device 200.

The flow path 241 is formed from the inlet side opening 211a side of the case 211 to the outlet side opening 211b side. That is, the flow path 241 is formed from the end portion of the exhaust gas processing unit 210 on the upstream side in the exhaust gas G flow direction to the end portion on the downstream side in the exhaust gas flow direction.

The flow path 241 has a plurality of enlarged portions 241a whose cross-sectional area of the flow path is expanded toward the cover 220 side. The flow path cross-sectional area at position C4 of the enlarged portion 241a is larger than the flow path cross-sectional area at position C2 of the flow path 241. The enlarged portion 241a is formed by a bead 224 provided on the cover 220 (third inner plate 221g, third outer plate 223g, fourth inner plate 221h, and fourth outer plate 223h). By having the enlarged portion 241a, the volume of the entire flow path 241 is increased, and the flow rate of air that can flow through the flow path 241 can be increased. Further, as the volume of the flow path 241 increases, the heat exchange area between the exhaust gas G flowing through the exhaust processing unit 210 and the air flowing through the flow path 241 also increases.

Similar to the exhaust treatment device 100, the flow path 241 is provided with a plurality of mesh members 50. The mesh member 50 damps the vibration of the entire cover 220 when the exhaust processing unit 210 vibrates and the cover 20 vibrates via the bracket 30.

Here, as in the modified example shown in FIG. 6, the flow path 241 is not formed over the entire area from the inlet side opening 211a to the outlet side opening 211b of the case 211, but is formed only in a part of the region. May be good.

In this modification, the catalyst 1 is held on the inner circumference of the exhaust treatment unit 210 via the catalyst holding mat 250 as a cushioning material. The flow path 241 is formed from the end of the exhaust gas processing unit 210 on the upstream side in the exhaust gas G flow direction to the upstream side of the catalyst holding mat 250 in the exhaust gas G flow direction.

The temperature of the exhaust gas G decreases as it flows from the upstream to the downstream. Further, since the catalyst holding mat 250 is provided around the catalyst 1, heat transfer from the exhaust gas G to the case 211 is suppressed. Therefore, the temperature of the main body of the exhaust treatment unit 210 around the catalyst 1 is relatively low.

Therefore, in this modification, the structure is such that the flow path 241 is not formed around the catalyst 1. This makes it possible to reduce the cost and weight of the exhaust treatment device 200.

In this modified example, the flow path 241 is formed only on the upstream side in the exhaust gas G flow direction. However, for example, when the temperature on the downstream side is higher than that on the upstream side due to the catalytic reaction of the catalyst 1, the flow path 241 may be formed only on the downstream side in the exhaust gas G flow direction, and the periphery of the catalyst 1 may be formed. Except, the flow path 241 may be formed only on the upstream side and the downstream side of the catalyst 1. That is, the flow path 241 may be formed in the portion of the exhaust processing unit 210 where the main body temperature is high so that the air flow path 241 can be cooled by the air flowing through the flow path 241.

As shown in FIGS. 3 to 7, the cover 220 has a communication hole 225 that communicates the flow path 241 with the outside. Since the cover 220 has the communication hole 225, the flow path 241 can take in air from the communication hole 225 in addition to the inflow port 240. That is, the flow rate of air in the flow path 241 can be increased. The inner plate 221 and the outer plate 223 around the boss portions 25 and 26 are notched or have a gap between the boss portions 25 and 26 and communicate with the flow path 241. Therefore, regardless of whether or not the sensor is inserted, air can be taken in as long as the surrounding wind flow is toward the openings around the boss portions 25 and 26.

Next, with reference to FIG. 7, the direction in which the inflow port 240 opens, the arrangement of the communication holes 225, and the like will be described. FIG. 7 is a diagram for explaining the arrangement of the exhaust treatment device 200 and the inflow of air into the exhaust treatment device 200. FIG. 7 schematically shows the arrangement of the exhaust treatment device 200 and the like in the engine room.

In FIG. 7, the left side of the paper is the front side of the vehicle. In the engine room, a radiator 91 (or a heat exchanger such as a condenser), an engine 92, an exhaust treatment device 200, and a passenger compartment panel 94 are provided in this order from the front side. A turbocharger 93 is attached to the inlet side opening 211a of the exhaust gas treatment device 200.

The air (arrow A0) that has flowed into the engine compartment from the front grill of the vehicle collides with equipment surrounding the exhaust treatment device 200, such as the radiator 91, the engine 92, or the passenger compartment panel 94, and changes the flow direction (FIG. FIG. See the dotted arrow in 7). That is, depending on the arrangement of the equipment in the engine room, air flows from a plurality of directions toward the exhaust treatment device 200 (cover 220).

In the exhaust treatment device 200, the inflow port 240 is opened so as to face the external air flow according to the air flow (air flow from a plurality of directions) around the exhaust treatment device 200 (cover 220). Further, the position, number, shape, etc. of the communication holes 225 provided in the cover 220 are determined according to the air flow (air flow from a plurality of directions) around the exhaust treatment device 200 (cover 220). In the present embodiment, the communication hole 225 is provided at a position where the air flowing along the dotted arrow A3 shown in FIGS. 5 to 7 flows into the flow path 241. As a result, a large amount of air can be efficiently taken into the flow path 241 as compared with the case where the communication hole 225 is not provided.

Further, the communication hole 225 may be provided in consideration of the air flow around the exhaust treatment device 200 (cover 220) so that the air flows into the portion of the flow path 241 where the air flow tends to be stagnant. In this case, the flow of air in the flow path 241 can be promoted, and the release of heat from the exhaust treatment unit 210 can be further promoted.

Next, the operation of the exhaust treatment device 200 will be described.

As shown in FIG. 5, the high-temperature exhaust gas G discharged from the engine flows into the exhaust processing unit 210 (case 211) from the inlet side opening 211a. The exhaust gas processing unit 210 (case 211) guides the exhaust gas G so that the exhaust gas G flows through the catalyst 1. The catalyst 1 purifies the exhaust gas G as in the case of the exhaust treatment device 100. The outlet side opening 211b guides the exhaust gas G purified by the catalyst 1 to the exhaust pipe. At this time, the exhaust processing unit 210 becomes hot due to the flow of the high-temperature exhaust gas G.

On the other hand, in the exhaust treatment device 200 of the present embodiment, the inflow port 240, the flow path 241 and the outflow port 242 are provided between the exhaust treatment unit 210 and the cover 220, similarly to the flow path 41 of the exhaust treatment device 100. It is formed. As a result, the exhaust treatment unit 210 whose temperature has been raised by the exhaust gas G can release heat to the air flowing through the flow path 241 (dotted line arrow A2 in FIG. 5) to suppress an increase in the temperature of the main body.

Further, the inflow port 240 is formed so that the flow path cross-sectional area (opening area) at the position C1 is larger than the flow path cross-sectional area at the position C2 of the flow path 241. This facilitates the flow of external air from the inflow port 240 to the flow path 241. That is, the flow rate of air in the flow path 241 increases. Therefore, the exhaust treatment unit 210 can further dissipate heat and further increase the temperature of the main body as compared with the case where the flow path cross-sectional area at the position C1 is not formed larger than the flow path cross-sectional area at the position C2 of the flow path 241. It can be suppressed.

Further, the outlet 242 is formed so that the flow path cross-sectional area (opening area) at the position C3 is larger than the flow path cross-sectional area at the position C2 of the flow path 241. As a result, the ventilation resistance of the flow path 241 is reduced, and air can flow more easily in the flow path 241. That is, the flow rate of air in the flow path 241 increases. Therefore, the exhaust treatment unit 210 can release more heat than the case where the flow path cross-sectional area at the position C3 is not formed larger than the flow path cross-sectional area at the position C2 of the flow path 241, and the temperature of the main body rises. It can be further suppressed.

Further, the flow path 241 has a plurality of expansion portions 241a whose flow path cross-sectional area is expanded toward the cover 220 side. As a result, the volume of the entire flow path 241 is increased, and the flow rate of air in the flow path 241 can be increased. Further, as the volume of the flow path 241 increases, the heat exchange area between the exhaust gas G flowing through the exhaust processing unit 210 and the air flowing through the flow path 241 also increases. Therefore, heat can be further released from the exhaust processing unit 210 as compared with the case where the enlarged unit 241a is not provided, and an increase in the temperature of the main body can be further suppressed.

Further, the cover 220 has a communication hole 225 for communicating the flow path 241 and the outside. The communication hole 225 is provided according to the air flow around the exhaust treatment device 200 (cover 220). As a result, more air can be taken into the flow path 241 than when the communication hole 225 is not provided. Therefore, heat can be further discharged from the exhaust processing unit 210 as compared with the case where the communication hole 225 is not provided, and an increase in the temperature of the main body can be further suppressed.

Further, the communication hole 225 may be provided at an arbitrary position of the cover 220 according to the air flow in the flow path 241. As a result, the flow of air in the flow path 241 can be promoted, and the heat release of the exhaust treatment unit 210 can be promoted.

Further, the exhaust treatment device 200 is required to suppress the radiated sound generated by the vibration as in the exhaust treatment device 100.

On the other hand, in the present embodiment, similarly to the exhaust treatment device 100, the fiber between the inner plate 221 (221a, 221b, 221g, and 221h) and the outer plate 223 (223a, 223b, 223g, and 223h). A fibrous material layer 222 (222a, 222b, 222g, and 222h) filled with a material by compression is provided. As a result, the vibration of the outer plate 223 is suppressed, so that the generation of radiated sound from the outer plate 223 can be suppressed.

Here, the inner plates 221 (221a, 221b, 221g, and 221h) and the outer plates 223 (223a, 223b, 223g, and 223h) receive repulsive forces from the fibrous material layer 222 (222a, 222b, 223g, and 222h). If they are equal everywhere, the difficulty of vibration when the vibration is transmitted is further improved. That is, the generation of radiated sound from the outer plate 223 can be further suppressed as compared with the case where the repulsive forces received from the fibrous material layers 222a, 222b, 222g, and 222h are different from each other.

On the other hand, in the present embodiment, the packing density of the fibrous material in the fibrous material layers 222a and 222b on the inflow port 240 side and the packing density of the fibrous material in the fibrous material layers 222g and 222h on the outflow port 242 side are made the same. ing. As a result, the inner plates 221 (221a, 221b, 222g, and 222h) and the outer plates 223 (223a, 223b, 223g, and 223h) receive the repulsive force from the fibrous material layer 222 (222a, 222b, 222g, and 222h). (Pressing pressure) becomes equal, and it becomes more difficult to vibrate. Therefore, it is possible to further suppress the generation of radiated sound from the outer plate 223.

Further, in the present embodiment, similarly to the exhaust treatment device 100, the other end 30b of the bracket 30 that holds the cover 220 in the exhaust treatment unit 210 is brought into contact with the first inner plate 221a and the second inner plate 221b. Thereby, the generation of the radiated sound from the outer plate 223 can be suppressed.

Further, in the exhaust treatment device 200 of the present embodiment, similarly to the exhaust treatment device 100, by providing the fiber material layer 222 between the inner plate 221 and the outer plate 223, radiant heat from the inner plate 221 to the outer plate 223 is provided. Is suppressed. As a result, it is possible to prevent the outer plate 23 from becoming hot, and it is possible to improve the heat insulating performance of the exhaust treatment device 100.

Here, the exhaust gas G flowing in the exhaust treatment device 200 has the highest temperature on the inflow port 240 (inlet side opening 211a) side, and the temperature decreases toward the outflow port 242 (outlet side opening 211b). That is, the inner plates 221a, 221b and the outer plates 223a, 223b on the inflow port 240 side are more likely to have higher temperatures than the inner plates 221g, 221h and the outer plates 223g, 223h on the outflow port 242 side.

On the other hand, in the present embodiment, the thickness T1 of the fibrous material layers 222a and 222b on the inflow port 240 side is made thicker than the thickness T2 of the fibrous material layers 222g and 222h on the outflow port 242 side. As a result, it is possible to suppress the transfer of radiant heat from the inner plates 221a and 221b to the outer plates 223a and 223b, and prevent the outer plates 223a and 223b from becoming hot. Therefore, the heat insulating performance of the exhaust treatment device 200 can be improved.

Further, the inner plates 221g and 221h and the outer plates 223g and 223h on the outflow port 242 side are relatively less likely to become hotter than the inflow port 240 side. Therefore, the thickness T2 of the fibrous material layers 222g and 222h on the outlet 242 side is larger than the thickness T1 of the fibrous material layers 222a and 222b on the inflow port 240 side within the range where the outer plates 223g and 223h are not heated by radiant heat. It's thin. According to this, the production cost of the exhaust treatment apparatus 200 (the cost for providing the fiber material layers 222g and 222h) can be reduced.

(Third embodiment)
Hereinafter, the exhaust treatment device 300 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic cross-sectional view of the exhaust treatment device 300.

First, the configuration of the exhaust treatment device 300 will be described.

As shown in FIG. 8, the exhaust treatment device 300 has catalysts 2 and 3 as exhaust treatment parts for treating the exhaust gas G, and is an exhaust treatment unit that guides the exhaust gas G to flow through the catalysts 2 and 3. A 310 and a cover 320 that covers the outer periphery of the exhaust processing unit 310 are provided. Further, the exhaust treatment device 300 further includes an oxygen concentration sensor 60 that detects the oxygen concentration of the exhaust gas G flowing through the exhaust treatment unit 310.

The exhaust treatment unit 310 includes a catalyst 2 as a first exhaust treatment component, a catalyst 3 as a second exhaust treatment component, a case 311 and a catalyst temperature riser 70 as a heating device for heating the catalyst 2. ..

Like the catalyst 1, the catalyst 2 is composed of a columnar honeycomb structure. A part of the outer peripheral surface of the catalyst 2 is fitted to the inner circumference of the case 311 via the cushioning material 312. That is, the case 311 is provided in a shape along a part of the catalyst 2.

Like the catalysts 1 and 2, the catalyst 3 is composed of a columnar honeycomb structure. The outer peripheral surface of the catalyst 3 is fitted to the inner circumference of the case 311 via the cushioning material 312. That is, the case 311 is provided in a shape along a part of the catalyst 3.

The catalyst 2 and the catalyst 3 are provided in the case 311 so that the central axis of the catalyst 2 and the central axis of the catalyst 3 are orthogonal to each other. As a result, the exhaust treatment device 300 can be made more compact in the length L direction as compared with the case where the catalysts 2 and 3 are arranged in series.

The catalyst heating device 70 has an electric heater 71 that is adjacent to the catalyst 2 and heats the catalyst 2, and an electrode 72 that is a part of the catalyst temperature raising device 70 and supplies electricity to the electric heater 71. The electric heater 71 heats the catalyst 2 by supplying electricity from a power source (not shown) via the electrode 72 to raise the temperature. As a result, the warm-up time of the catalyst 2 can be shortened and the catalyst 2 can be activated at an early stage. The catalyst heating device 70 may be provided on the catalyst 3. Further, the catalysts 2 and 3 and the catalyst heating device 70 may be of a type in which a conductive carrier on which a catalyst is supported is energized to raise the temperature.

The case 311 is a substantially U-shaped tubular member. An entrance side opening 311a opens at one end of the case 311. An outlet side opening 311b opens at the other end of the case 311.

The inlet side opening 311a is connected to the exhaust manifold (not shown) of the engine. As a result, the exhaust gas G discharged from the engine passes through the exhaust manifold and the inlet side opening 311a and flows into the case 311. That is, the end portion of the case 311 on the inlet side opening 311a side is the end portion of the exhaust gas processing unit 310 on the upstream side in the exhaust gas flow direction.

The outlet side opening 311b is connected to an exhaust pipe (not shown). As a result, the exhaust gas G that has passed through the case 311 flows into the exhaust pipe. That is, the end portion of the case 311 on the outlet side opening 311b side is the end portion of the exhaust gas processing unit 310 on the downstream side in the exhaust gas flow direction.

On the upstream side of the exhaust gas processing unit 310 in the exhaust gas flow direction, a boss unit 325 that communicates the inside and the outside of the case 311 is provided. The oxygen concentration sensor 60 is inserted into the boss portion 325.

The cover 320 is a member that covers the outer periphery of the exhaust processing unit 310. The cover 320 is provided with a predetermined distance from the outer circumference of the exhaust processing unit 310. The cover 320 includes an inner plate 321 provided so as to face the outer periphery of the exhaust treatment unit 310, a fibrous material layer 322 provided on the outer periphery of the inner plate 321 and an outer plate 323 covering the outside of the fibrous material layer 322. Have.

The inner plate 321 is provided so as to face the outer circumference of the case 311 (exhaust processing unit 310) having a shape along a part of the catalyst 2 and a part of the catalyst 3. That is, the inner plate 321 is formed in a shape along a part of the catalyst 2 and a part of the catalyst 3. The outer plate 323 is formed in a shape that conforms to the shape of the inner plate 321. According to this, the exhaust treatment device 300 can be made compact in the length L direction. Since the method of attaching the outer plate 323 to the inner plate 321 and the method of providing the fiber material layer 322 are the same as those of the exhaust treatment devices 100 and 200, the description thereof will be omitted.

The cover 320 is formed in a shape in which the boss portion 325 is exposed to the outside. That is, the cover 320 is formed in a shape in which a part of the oxygen concentration sensor 60 is exposed. By forming the cover 320 in such a shape, the oxygen concentration sensor 60 can be easily attached, and the exhaust treatment device 300 can be easily assembled.

Further, the cover 320 is formed in a shape in which the electrodes 72 are exposed. This facilitates the wiring between the electrode 72 and the power source, and facilitates the assembly of the exhaust treatment device 300.

By providing the cover 320 at a distance from the outer periphery of the exhaust treatment unit 310, the inflow port 340 through which air flows and the air flowing in from the inflow port 340 pass between the exhaust treatment unit 310 and the cover 320. A flow path 341 and an outlet 342 through which the air passing through the flow path 341 flows out are formed.

The inflow port 340 opens so as to face the flow of external air.

The flow path 341 is formed from the inlet side opening 311a side of the case 311 to the outlet side opening 311b side. That is, the flow path 341 is formed from the end portion of the exhaust gas processing unit 310 on the upstream side in the exhaust gas flow direction to the end portion on the downstream side in the exhaust gas flow direction.

Next, the operation of the exhaust treatment device 300 will be described.

The high-temperature exhaust gas G discharged from the engine flows into the exhaust processing unit 310 (case 311) from the inlet side opening 311a. The exhaust gas processing unit 310 (case 311) guides the exhaust gas G so that the exhaust gas G flows through the catalysts 2 and 3. The catalysts 2 and 3 purify the exhaust gas G as in the case of the exhaust treatment devices 100 and 200. The outlet side opening 311b guides the exhaust gas G purified by the catalysts 2 and 3 to the exhaust pipe. At this time, the exhaust processing unit 310 becomes hot due to the flow of the high-temperature exhaust gas G.

On the other hand, in the exhaust treatment device 300 of the present embodiment, the inflow port 340, the flow path 341, and the outflow port 342 are formed between the exhaust treatment unit 310 and the cover 320, similarly to the exhaust treatment devices 100 and 200. .. As a result, the exhaust processing unit 310 whose temperature has been raised by the exhaust gas G can release heat to the air (dotted line arrow A4) flowing through the flow path 341 to suppress an increase in the temperature of the main body.

Further, the exhaust treatment device 300 is required to suppress the radiated sound generated by the vibration as in the exhaust treatment devices 100 and 200.

On the other hand, in the present embodiment, similarly to the exhaust treatment devices 100 and 200, the fiber material layer 322 compressed and filled with the fiber material is provided between the inner plate 321 and the outer plate 323. As a result, the vibration of the outer plate 323 is suppressed, so that the generation of radiated sound from the outer plate 223 can be suppressed.

Further, in the exhaust treatment device 300, the catalyst 2 and the catalyst 3 are provided in the case 311 so that the central axis of the catalyst 2 and the central axis of the catalyst 3 are orthogonal to each other. Further, the inner plate 321 is formed in a shape along a part of the catalyst 2 and a part of the catalyst 3. According to these, the exhaust treatment device 300 can be made compact in the length L direction.

Further, the cover 320 is formed in a shape in which a part of the oxygen concentration sensor 60 is exposed. According to this, the oxygen concentration sensor 60 can be easily attached, and the exhaust treatment device 300 can be easily assembled.

Further, the cover 320 is formed in a shape in which the electrodes 72 are exposed. This facilitates wiring to the electrode 72 and facilitates assembly of the exhaust treatment device 300.

Hereinafter, modifications of the exhaust treatment devices 100, 200, and 300 will be described with reference to FIGS. 9 to 11. The structure of the modified example described below can be applied to any of the exhaust treatment devices 100, 200, and 300 according to the first to third embodiments. Hereinafter, a modified example of the exhaust treatment device 100 will be described as a typical example.

First, with reference to FIG. 9, the exhaust treatment device 400 according to the first modification of the exhaust treatment device 100 will be described.

FIG. 9 is an enlarged schematic view of a cross section of the cover 420 of the exhaust treatment device 400. As shown in FIG. 9, the exhaust treatment device 400 differs from the exhaust treatment device 100 in that the outer plate 423 of the cover 420 has a two-layer structure.

The outer plate 423 of the cover 420 has a two-layer structure having a first outer plate 423a provided on the outer periphery of the fibrous material layer 22 and a second outer plate 423b provided on the outer periphery of the first outer plate 423a.

The thickness of the first outer plate 423a and the second outer plate 423b are different. The material of the first outer plate 423a and the second outer plate 423b may be the same or different.

In the exhaust treatment device 400, vibration is transmitted from the engine in the same manner as the exhaust treatment device 100. In the exhaust treatment device 400, the vibration transmitted from the engine is transmitted from the inner plate 21 to the second outer plate 423b via the first outer plate 423a.

Here, the thickness of the first outer plate 423a and the thickness of the second outer plate 423b are different. That is, the first outer plate 423a and the second outer plate 423b have different natural frequencies. Therefore, the vibration transmitted from the inner plate 21 to the first outer plate 423a is damped in the process of being transmitted from the first outer plate 423a to the second outer plate 423b. As a result, the vibration of the entire outer plate 423 is suppressed. Therefore, it is possible to further suppress the generation of radiated sound from the outer plate 423 as compared with the case where the outer plate 423 does not have a two-layer structure.

Next, with reference to FIG. 10, the exhaust treatment device 500 according to the second modification of the exhaust treatment device 100 will be described.

FIG. 10 is an enlarged schematic view of a cross section of the cover 520 of the exhaust treatment device 500. As shown in FIG. 10, the exhaust treatment device 500 differs from the exhaust treatment devices 100 and 400 in that a plurality of protrusions 521a and 523a are formed on at least one of the inner plate 521 or the outer plate 523 of the cover 520.

The cover 520 includes an inner plate 521 provided so as to face the outer periphery of the exhaust treatment unit 10, a fibrous material layer 522 provided on the outer periphery of the inner plate 521, and an outer plate 523 covering the outer periphery of the fibrous material layer 522. Have. The fibrous material layer 522 has the same structure and function as the fibrous material layer 22, except that the cross-sectional shape of the fibrous material layer 522 is different from that of the fibrous material layer 22.

A plurality of protrusions 521a are formed on the inner plate 521. Specifically, a plurality of protrusions 521a are formed on the surface of the inner plate 521 on the inner peripheral surface side.

Further, a plurality of protrusions 523a are formed on the outer plate 523. Specifically, a plurality of protrusions 523a are formed on the outer peripheral surface side surface of the outer plate 523.

In the exhaust treatment device 500, the protrusion 521a is formed on the inner plate 521 to increase the surface area of the inner plate 521 on the inner peripheral surface side, and as a result, the surface area of the flow path 41 is increased. As a result, the heat of the exhaust treatment unit 10 and the inner plate 521 can be easily released to the air flowing through the flow path 41. Therefore, it is possible to further suppress an increase in the temperature of the main body of the exhaust processing unit 10 as compared with the case where the protrusion 521a is not formed.

Further, by forming the protrusion 523a on the outer plate 523, the surface area on the outer peripheral surface side of the outer plate 523 is increased. By increasing the surface area on the outer peripheral surface side of the outer plate 523, the contact area between the outer plate 523 and the outside air is expanded, and heat can be easily released from the outer plate 523. Therefore, when the temperature of the outer plate 523 rises due to radiant heat or the like, the temperature rise of the outer plate 523 can be further suppressed as compared with the case where the protrusion 523a is not formed.

As described above, by forming the plurality of protrusions 521a and 523a on at least one of the inner plate 521 or the outer plate 523 of the cover 520, it is possible to suppress an increase in the temperature of the entire exhaust treatment device 500.

A combination of forming protrusions 521a and 523a on the inner plate 521 and the outer plate 23 (that is, forming the protrusions 521a only on the inner plate 521, forming the protrusions 523a only on the outer plate 523, or forming the protrusions 521a and 523a only on the inner plate 521 and the inner plate 521 and Whether the protrusions 521a and 523a are formed on the outer plate 523) can be appropriately selected according to the heat release property required by the exhaust treatment device 500. Further, the number, size, shape, etc. of the protrusions 521a and 523b are also appropriately changed according to the heat release property required by the exhaust treatment device 500.

Next, with reference to FIG. 11, the exhaust treatment device 600 according to the third modification of the exhaust treatment device 100 will be described.

FIG. 11 is an enlarged schematic view of a cross section of the cover 620 of the exhaust treatment device 600. As shown in FIG. 11, the exhaust treatment device 600 differs from the exhaust treatment devices 100, 400, and 500 in that the inner plate 621 of the cover 620 is a punching metal having a plurality of holes 621a.

The inner plate 621 of the cover 620 is a punching metal having a plurality of holes 623a. Therefore, a part of the surface of the fibrous material layer 22 on the inner plate 621 side is exposed to the flow path 41.

Similar to the exhaust treatment device 100, the exhaust treatment device 600 may generate radiated sound from the exhaust treatment unit 10 and the outer plate 23 when vibration is transmitted from the engine.

Here, the exhaust treatment device 600 guides the radiated sound generated from the exhaust treatment unit 10 to the fiber material layer 22 through the holes 621a by making the inner plate 621 a punching metal. The fibrous material layer 22 has a sound absorbing property. Therefore, the radiated sound guided to the fibrous material layer 22 is attenuated by the fibrous material layer 22. As a result, the radiated sound generated from the exhaust processing unit 10 is attenuated. That is, the generation of radiated sound from the entire exhaust treatment device 600 is suppressed. Therefore, the radiated sound generated from the entire exhaust treatment device 600 can be further suppressed as compared with the case where the hole 621a is not provided.

The number, size, shape, etc. of the holes 623a are appropriately changed according to the magnitude of the radiated sound generated from the exhaust treatment unit 10, the sound absorbing performance of the fibrous material layer 22, and the like.

According to the above embodiment, the following effects are obtained.

The exhaust treatment devices 100, 200, 300, 400, 500, 600 have a catalyst 1 (or catalysts 2 and 3) for treating the exhaust gas G, and the exhaust gas G flows through the catalyst 1 (or the catalysts 2 and 3). The exhaust processing units 10, 210, 310 are provided, and the covers 20, 220, 320, 420, 520, 620 covering the outer periphery of the exhaust processing units 10, 210, 310 are provided. The covers 20, 220, 320, 420, 520, 620 have inner plates 21,221, 321 and 521, 621 provided so as to face the outer periphery of the exhaust processing units 10, 210, 310, and inner plates 21,221, The fibrous material layers 22,222,322,522 provided on the outer periphery of the 321, 521,621 and the outer plates 23,223,323,423,523 covering the outer periphery of the fibrous material layer 22,222,322,522. Between the covers 20, 220, 320, 420, 520, 620 and the exhaust treatment units 10, 210, 310, the inflow ports 40, 240, 340 and the inflow ports 40, 240, 340 into which air flows in are 40, 240, 340. The flow paths 41,241,341 through which the air flowing in from the flow path 41,241,341 and the outflow ports 42,242,342 through which the air passing through the flow paths 41,241,341 pass are formed.

The exhaust treatment device 100, 200, 300, 400, 500, 600 has a catalyst 1 (or catalysts 2 and 3) for treating the exhaust gas G at 950 ° C. or higher, and the exhaust gas in the catalyst 1 (or the catalysts 2 and 3). Exhaust treatment units 10, 210, 310 for guiding G to flow, and covers 20, 220, 320, 420, 520, 620 for covering the outer periphery of the exhaust treatment units 10, 210, 310 are provided. The covers 20, 220, 320, 420, 520, 620 have inner plates 21,221, 321 and 521, 621 provided so as to face the outer periphery of the exhaust processing units 10, 210, 310, and inner plates 21,221, The fibrous material layers 22,222,322,522 provided on the outer periphery of the 321, 521,621 and the outer plates 23,223,323,423,523 covering the outer periphery of the fibrous material layer 22,222,322,522. Between the covers 20, 220, 320, 420, 520, 620 and the exhaust treatment units 10, 210, 310, the inflow ports 40, 240, 340 and the inflow ports 40, 240, 340 into which air flows in are 40, 240, 340. The flow paths 41,241,341 through which the air flowing in from the flow path 41,241,341 and the outflow ports 42,242,342 through which the air passing through the flow paths 41,241,341 pass are formed. The fiber material layers 22,222,322,522 have a thickness of 3 to 20 mm, and the exhaust treatment portions 10,210,310 and covers 20,220,320,420,520,620 in the flow paths 41,241,341 The gap size of is 3 to 20 mm.

According to these configurations, the exhaust treatment units 10, 210, 310 can release heat to the air flowing through the flow paths 41, 241, 341 to suppress an increase in the temperature of the main body.

Further, by providing the fibrous material layers 22,222,322,522, the inner plates 21,221,321,521,621 and the outer plates 23,223,323,423,523 are less likely to vibrate, and the inner plates are less likely to vibrate. The vibrations of 21,221,321,521,621 are difficult to be transmitted to the outer plates 23,223,323,423,523. Therefore, the vibration of the outer plates 23, 223, 323, 423, 523 can be suppressed, and the generation of radiated sound from the outer plates 23, 223, 323, 423, 523 can be suppressed. That is, it is possible to suppress an increase in the temperature of the main body and suppress the generation of radiated sound.

Further, by providing the fibrous material layers 22,222,322,522, the transfer of radiant heat from the inner plates 21,221,321,521,621 to the outer plates 23,223,323,423,523 is suppressed. .. As a result, it is possible to prevent the outer plates 23, 223, 323, 423, 523 from becoming hot, and it is possible to improve the heat insulating performance of the exhaust treatment device 100. Therefore, it is possible to prevent heat damage to the parts around the main body.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. No.

For example, the exhaust treatment device 300 has been described as an exhaust treatment device including the oxygen concentration sensor 60 and the catalyst temperature raising device 70. However, the oxygen concentration sensor 60 and the catalyst heating device 70 can be applied to all the exhaust treatment devices 100, 200, 300, 400, 500, 600. In the exhaust treatment devices 100, 200, 400, 500, 600 to which the oxygen concentration sensor 60 and the catalyst temperature raising device 70 are applied, the covers 20, 220, 420, 520, and 620 are similar to the cover 320 of the exhaust treatment device 300. A part of the oxygen concentration sensor 60 and the electrode 72 are formed in an exposed shape.

100,200,300,400,500,600 Exhaust treatment device 1 Catalyst (exhaust treatment parts)
2 Catalyst (first exhaust treatment part)
3 Catalyst (second exhaust treatment part)
10,210,310 Exhaust treatment unit 20,220,320,420,520,620 Cover 21,221,321,521 Inner plate 22,222,322,522 Fiber material layer (mat)
23,223,323,423,523 Outer plate 40,240,340 Inflow port 41,241,341 Flow path 42,242,342 Outlet 60 Oxygen concentration sensor 224 Bead 225 Communication hole 241a Expansion part 250 Catalyst holding mat (buffer) Material)
423a First outer plate 423b Second outer plate 521a Protrusion 523a Protrusion 621 Inner plate (punching metal)
621a hole

Claims (20)

An exhaust treatment unit that has an exhaust treatment component that processes exhaust gas and guides the exhaust gas to flow to the exhaust treatment component.
A cover that covers the outer circumference of the exhaust treatment unit and
With
The cover has an inner plate provided so as to face the outer circumference of the exhaust processing unit, a mat provided on the outer circumference of the inner plate, and an outer plate covering the outer circumference of the mat.
Between the cover and the exhaust treatment unit, there are an inflow port where air flows in, a flow path through which air flowing in from the inflow port passes, and an outflow port through which air passing through the flow path flows out. It is formed,
An exhaust treatment device characterized by the fact that. An exhaust treatment unit that has an exhaust treatment component that processes exhaust gas at 950 ° C or higher and guides the exhaust gas to flow through the exhaust treatment component.
A cover that covers the outer circumference of the exhaust treatment unit and
With
The cover has an inner plate provided so as to face the outer circumference of the exhaust processing unit, a mat provided on the outer circumference of the inner plate, and an outer plate covering the outer circumference of the mat.
Between the cover and the exhaust treatment unit, there are an inflow port where air flows in, a flow path through which air flowing in from the inflow port passes, and an outflow port through which air passing through the flow path flows out. Formed,
The thickness of the mat is 3 to 20 mm, and the gap dimension between the exhaust processing portion and the cover in the flow path is 3 to 20 mm.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to claim 2.
The thickness of the mat is 5 to 15 mm, and the gap dimension in the flow path is 3 to 10 mm.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 3.
The flow path is formed from the end on the upstream side in the exhaust gas flow direction to the end on the downstream side in the exhaust gas flow direction in the exhaust treatment unit.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 4.
The flow path has a plurality of enlarged portions in which the cross-sectional area of the flow path is expanded toward the cover side.
The enlarged portion is formed by a bead provided on the cover.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 5.
The inflow port opens so as to face the flow of external air.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 6.
At least one of the inflow port and the outflow port is formed so that the opening area is larger than the cross-sectional area of the flow path.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 7.
The cover has a communication hole for communicating the flow path with the outside.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 8.
The thickness of the mat on the inlet side is thicker than that of the mat on the outlet side.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 9.
The packing density of the fibrous material in the mat on the inlet side and the packing density of the fibrous material in the mat on the outlet side are the same.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 10.
The outer plate has a two-layer structure having a first outer plate provided on the outer periphery of the mat and a second outer plate provided on the outer periphery of the first outer plate.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 11.
A plurality of protrusions are formed on at least one of the inner plate or the outer plate.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 11.
The inner plate is a punching metal having a plurality of holes.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 13.
The exhaust treatment unit is further provided with a bracket for holding the cover.
The inner plate has a first inner plate and a second inner plate that are divided in the circumferential direction.
One end of the bracket is attached to the exhaust treatment unit and
The other end of the bracket is attached while one end of the first inner plate and one end of the second inner plate are abutted against each other.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 14.
The exhaust treatment unit has a heating device including an electric heater for heating the exhaust treatment component and an electrode for supplying electricity to the electric heater.
The cover is formed in a shape in which the electrodes are exposed.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 15.
The exhaust treatment component includes a first exhaust treatment component and a second exhaust treatment component.
The first exhaust treatment component and the second exhaust treatment component are provided so that the central axis of the first exhaust treatment component and the central axis of the second exhaust treatment component are orthogonal to each other.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to claim 16.
The inner plate is formed in a shape along a part of the first exhaust treatment component and a part of the second exhaust treatment component.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 17.
An oxygen concentration sensor for detecting the oxygen concentration of the exhaust gas flowing through the exhaust processing unit is further provided.
The cover is formed in a shape that exposes a part of the oxygen concentration sensor.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to any one of claims 1 to 18.
The exhaust treatment device is mounted on the vehicle and
The inflow port is located on the front side of the vehicle and is located on the front side of the vehicle.
The outlet is located on the rear side of the vehicle.
An exhaust treatment device characterized by the fact that. The exhaust treatment apparatus according to claim 1.
The exhaust treatment component is held on the inner circumference of the exhaust treatment unit via a cushioning material.
The flow path is formed from an end on the upstream side of the exhaust gas flow direction in the exhaust treatment section to the upstream side of the cushioning material in the exhaust gas flow direction.
An exhaust treatment device characterized by the fact that.

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