JPH0754640A - Exhaust emission control device - Google Patents

Abstract

PURPOSE:To decrease generation of white smoke by closing a purifying passage in a first member when the temperature of exhaust gas is less than the set temperature, so as to open a bypass passage by means of a second member, and opening the purifying passage when the temperature of exhaust gas is more than the set temperature, so as to close the bypass passage. CONSTITUTION:When the detected temperature of a sensor 1 is not more than the set temperature, a valve 12 is in the home position for closing an exhaust gas inflow port 5a, and a valve 13 is placed in the home position for opening an exhaust gas inflow port 6a, thereby, exhaust gas to flow from the upstream side is guided into a bypass passage 6. When the detected temperature of a temperature sensor 11 becomes more than the set temperature, an actuator 14 acts in the direction to open the valve 12, while actuators 15A, 15B act in the direction to close the valve 13. Accordingly, exhaust gas is allowed to flow into a purifying passage 5 and purified by a catalyst 3. Thereby, since inflow of exhaust gas having low temperature to the catalyst is decreased, the amount of hydrocarbon is decreased, and the generation of white smoke is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust emission control device provided in an exhaust passage for exhaust gas of an engine.

[0002]

2. Description of the Related Art Conventionally, an exhaust gas purification device for purifying exhaust gas containing harmful components discharged from an engine is mounted in an exhaust passage communicating with an exhaust port of the engine. In particular, a nitrogen oxide (Nox) catalyst is usually installed in the exhaust passage of a diesel engine to purify nitrogen oxide (Nox), but in addition to this, it is included in the exhaust gas of a diesel engine. When the soluble organic component (SOF component) is to be particularly purified, an SOF oxidation catalyst is attached.

[0003]

However, each of these catalysts has a catalyst activation temperature at which it does not function effectively as a catalyst unless it exceeds a certain temperature, and when the exhaust temperature is relatively low such as during idling, each catalyst is activated. It will be placed outside the temperature range. In particular, when the exhaust gas is introduced into the SOF oxidation catalyst when it is outside the activation temperature range,
That is, when the exhaust gas having a low temperature is flown to the catalyst that has not reached the activation temperature, unburned fuel accumulates in the catalyst without being purified. When starting and accelerating from such a state, there is a problem that this unburned fuel is released from the catalyst into the atmosphere and vapor-condenses, and a large amount of white smoke is generated.

[0004]

Therefore, an exhaust gas purification apparatus of the present invention includes a purification passage constituted by a first member for holding a tubular catalyst provided in an exhaust passage for exhaust gas discharged from an engine. A second member that is integrally provided in at least one of the inside and the outer periphery of the first member and that constitutes a bypass passage that bypasses the first member; and when the temperature of the exhaust gas is less than a set temperature. The purification passage in the first member is closed, the high-pass passage by the second member is opened, the purification passage is opened when the temperature of the exhaust gas is equal to or higher than a set temperature, and the bypass passage by the second member is opened. It is characterized by having an opening / closing mechanism for controlling opening / closing so as to close.

[0005]

When the temperature of the exhaust gas discharged from the engine is lower than the set temperature, the purifying passage, which is provided in the exhaust passage and is composed of the first member holding the cylindrical catalyst, is closed by the opening / closing mechanism, and the first member A bypass passage formed of a second member that is integrally provided in at least one of the inside and the outer circumference and that bypasses the first member is opened by the opening / closing mechanism. When the temperature of the exhaust gas is equal to or higher than the set temperature, the purification passage is opened by the opening / closing mechanism and the bypass passage is closed by the opening / closing mechanism. In addition, the second member is a first member that holds the catalyst.
Since it is provided integrally with the member, when the exhaust gas flows through the bypass passage, the heat of the exhaust gas is transferred to the catalyst via the first member and the catalyst is heated. Furthermore, since the bypass passage is provided in at least one of the inside and the outer periphery of the first member holding the catalyst, the bypass passage can be formed without increasing the size of the exhaust gas purification device.

[0006]

EXAMPLES Hereinafter, some examples and modifications of the present invention will be described. The same members in each example and modifications are as follows.
The same reference numerals as those used in the first embodiment are attached, and the description thereof will be limited to the first embodiment, and the duplicated description will be omitted.

(First Embodiment) In FIG. 1, reference numeral 1 is
1 shows an exhaust emission control device which is connected to an exhaust manifold 2A of a diesel engine E (hereinafter referred to as "engine E") and which is mounted in an exhaust gas exhaust passage 2 including a pre-muffler 2B.

This exhaust gas purification device 1 has a purification passage 5 formed inside a canister container 4 as a first member for holding a cylindrical catalyst 3 provided in an exhaust passage 2 and an outer periphery of the canister container 4. It is mainly composed of a catalytic converter 9 having a housing 7 as a second member that is integrally provided and forms a bypass passage 6, and an opening / closing mechanism 8 that controls opening / closing of the purification passage 5 and the high-pass passage 6.

The expansion portion 4a of the canister container 4 has a structure shown in FIG.
As shown in, the catalyst 3 is housed and held via the wire mesh 10. Both ends 4b, 4 of the canister container 4
The diameter c is narrower than the diameter of the exhaust passage 2.

The catalyst 3 has a honeycomb structure in which a large number of narrow passages are laminated in the same direction, and a catalyst substance is applied to a carrier made of, for example, ceramic. The catalyst 3 is exhausted when passing through the side wall of the narrow passage. It is an oxidation catalyst that adsorbs and purifies harmful components contained in gas. The catalyst 3 purifies the soluble organic component (SOF component) contained in the exhaust gas.

The housing 7 is formed by an appropriate method such as sheet metal in a shape that is familiar to the canister container 4, and both ends 7a and 7b of the housing 7 are squeezed so as to have the same diameter as the exhaust passage 2. ing. That is, canister container 4
A bypass passage 6 that connects to the exhaust passage 2 is formed between the housing 7 and the housing 7, and the inside of the canister container 4 serves as an exhaust gas purification passage 5.

Next, the opening / closing mechanism 8 will be described. As shown in FIG. 2, the opening / closing mechanism 8 includes a temperature sensor 11 for detecting the temperature of the exhaust gas flowing in the exhaust passage 2, and a valve member for opening / closing the exhaust gas inlets 5a, 6a in the purification passage 5 and the bypass passage 6. Valves 12, 13 and actuator 1
4, 15A, 15B and a control means 16 for controlling the opening and closing of the valves 12, 13 based on the temperature detected by the temperature sensor 11.

The temperature sensor 11 is fixed to the peripheral wall 2a of the exhaust passage 2 located upstream of the catalyst 3 and is connected to the control means 16
The temperature of the exhaust gas in the exhaust passage 2 upstream of the catalyst 3 is detected and the temperature information as the detection result is sent to the control means 16.

The valve 12 is a well-known butterfly valve which is a first opening / closing valve, is disposed in the exhaust gas inlet 5a, and is connected to the movable rod 14a of the actuator 14. The valve 12 is closed when the engine is started or when the exhaust gas temperature is relatively low such as idling, and is opened as shown by a two-dot chain line when the exhaust gas temperature becomes equal to or higher than the set temperature.

The valve 13 is a second opening / closing valve for opening / closing the exhaust gas inlet 6a, and as shown in FIG. 3 (a), it has an upper valve 13A which is formed in an arch shape and is vertically divided into two parts. Valve 1
3B and 3B. Both ends 13Aa, 13Ab and 13Ba, 13 of the upper valve 13A and the lower valve 13B, respectively.
Shafts 17A, 17B and 18A, 18B are fixed to Bb so as to be positioned on coaxial lines, respectively, and are rotatably supported on the peripheral wall 2a of the exhaust passage 2.

One ends of links 19 and 20 are fixed to the shaft 17A and the shaft 18B outside the passage 2, respectively. At the other end of each of the links 19 and 20, the actuator 15A,
Rods 15a and 15b of 15B are connected to each other (see FIG. 2).

As shown in FIG. 3 (b), the upper valve 13A and the lower valve 13B are placed at a position where they are overlapped with each other and lie in the passage when the temperature of the exhaust gas is relatively low at the time of engine starting or idling. When the temperature of the exhaust gas becomes equal to or higher than the set temperature, the exhaust gas is placed in a state of being raised in the passage cross-sectional direction, as shown in FIG. That is, the state of the valve 13 shown in FIG. 3A is the state when the bypass passage 6 is closed.
The state of the valve 13 shown in (b) is the state when the bypass passage 6 is opened.

When the upper valve 13A and the lower valve 13B are in the open state (FIG. 3a), the inner surface 13Ac, 1 of each valve is
The opening 21 that connects the purification passage 5 and the gas passage 3 is formed by 3Bc. The valve 12 is in the closed state shown by the solid line in FIG. 2, and the valve 13 is in the open state shown in FIG. 3B as the home position (initial position).

The control means 16 is a control device mainly including a well-known microcomputer, and the set temperature of exhaust gas for issuing a drive signal to the actuators 14 and 15 (A, B) is recorded in its recording circuit. The valves 12 and 13 are switched and controlled according to the temperature detected by the temperature sensor 11.

Now, the characteristics of the catalyst 3 will be described with reference to FIG. FIG. 11 shows the characteristics of the catalyst 3 (FIG. 2) when the vehicle equipped with the exhaust emission control device 1 of the present invention is in the rapid acceleration state after 6 hours of idle rotation. The horizontal axis represents the measurement time, and the vertical axis represents the hydrocarbon (HC) and white smoke concentration downstream of the catalyst and the catalyst temperature.

According to this figure, it can be seen that the concentration of white smoke and HC decreases when the catalyst temperature rises to around 300 ° C. after the rapid acceleration state continues to some extent. That is, the catalyst 3
It can be seen that the purification efficiency is improved when is heated by the exhaust gas to reach the catalyst activation temperature.

Therefore, the set temperature of the exhaust gas for switching the valves 12 and 13 is set to 300 ° C. according to the characteristics of the catalyst 3 used in this embodiment. Since the catalyst activation temperature varies depending on the type of catalyst, it is desirable to change the set temperature set in the control device according to the type of catalyst.

The operation of the exhaust purification system 1 having such a configuration will be described. When the engine E is in the operating state, after a predetermined operation cycle of the internal combustion engine is performed, exhaust gas is discharged from the inside of a cylinder (not shown) into the exhaust passage 2 via the exhaust manifold 2A.

The temperature of the exhaust gas is detected by the temperature sensor 11, and the detected temperature information is sent to the control device 16. At this time, if the temperature detected by the sensor 11 is below the set temperature, the valve 12 is in the home position position where the exhaust gas inlet 5a is closed, while the valve 13 is located in the home position position where the exhaust gas inlet 6a is opened. Therefore, the exhaust gas flowing from the upstream side is
Be led to.

At this time, since the heat of the exhaust gas introduced into the bypass passage 6 is conducted to the catalyst 3 through the canister container 4, the exhaust gas at low temperature does not have to pass directly to the catalyst 3 but to some extent the catalyst 3 Can be heated. Therefore,
The rise time until reaching the catalyst activation temperature is shortened. Further, since exhaust gas at low temperature can be discharged without passing through the catalyst 3 which has not yet reached the activation temperature, accumulation of HC on the catalyst 3 can be prevented.

When the exhaust gas temperature rises and the temperature detected by the temperature sensor 11 exceeds the set temperature after the operating state continues for a while, a drive signal is sent from the control device 16 to each actuator, and the actuator 14 opens the valve 12. To
The actuators 15A and 15B act in the direction of closing the valves 13A and 13B. Therefore, the exhaust gas does not flow into the bypass passage 6 but flows into the canister container 4, that is, the purification passage 5, is purified by the catalyst 3, and is then discharged.

(Modification 1 of the first embodiment) This modification is
The mounting position of the valve 12 and the direction of the valve 13 are changed. 4 and 5, the valves 13A and 13B are second butterfly valves arranged so as to be divided into left and right in a cross section of the exhaust passage 2, and a first long shaft 18C that supports the valve 13B has a first butterfly valve. The valve 12 as a butterfly valve is fixed by an appropriate method such as welding.

The valve 12 has the shaft 18C of the valve 13B fixed in a direction orthogonal to the valves 13A and 13B, that is, by changing the phase by 90 °, and opens the state shown in FIG. The state shown is a closed state. As shown in FIG. 4, the valve 13 is in a closed state when the valves 13A and 13B are in the same plane, and as shown in FIG.

With such a structure, the valve 13B can be installed in FIG.
The valve 12 is driven by the actuator 15B shown in FIG.
Also, since the actuator 14 that drives the valve 12 in the first embodiment is unnecessary, the number of parts can be reduced and the size of the device can be reduced.

In FIG. 6A, the valve 12 in FIG.
Split into half-moon shaped valves 12A and 12B, which are valve 13
A and 13B are fixed to long shafts 17C and 18C that rotatably support them. The valves 12A and 12B are the valves 13A and 13B.
It is fixed in a direction orthogonal to.

At this time, the control means 16 shown in FIG. 2 has either one of the actuator 15A and the actuator 15B in addition to the set temperature as a condition for issuing a drive signal for driving the actuators 15A and 15B. The intermediate temperature for driving is set (in this case, the actuator 15B is driven). This intermediate temperature is set to a temperature lower than the set temperature.

According to this structure, the temperature sensor 11
If the detected temperature of is the intermediate temperature, the actuator 15B
6A is driven, the valves 12A, 12B, 13A and 13B placed in the home position shown in FIG. 6A are in a state where the valve 12B is opened and the valve 13B is closed as shown in FIG. 6B. Become. When the temperature detected by the sensor is the set temperature, the actuators 15A and 15B are driven, and
As shown in (c), the open state of the valves 12A and 12B and the valve 1
3A and 13B are fully opened.

Accordingly, the inflow of exhaust gas having a low temperature into the catalyst 3 can be prevented, and the amount of hydrocarbons HC accumulated in the catalyst 3 can be reduced. Also. Valves 12A and 13A and valves 12B and 13
Since B can be driven individually, the bypass passage 6
The amount of exhaust gas flowing into the purification passage 5 can be adjusted.

(Modification 2 of the first embodiment) This modification is
As shown in FIG. 7, a valve member composed of a fixed plate 22 and a movable plate 23 is provided at the exhaust gas inlets 5a and 6a. In the fixed plate 22, fan-shaped spaces 22a are formed at equal intervals, and fan-shaped valve portions 22b are formed between the intervals, and the fan-shaped valve portions 22b are formed in the exhaust gas inflow passage 6a while being in contact with the exhaust gas inlet 5a. It is fixed.

The movable plate 23 has a plurality of notches 23a formed in its outer shape at the same intervals as the fan-shaped spaces 22a, and the fan-shaped valve portion 22 is provided between the notches 23a.
A valve portion 23b corresponding to b is formed.

The outer diameter of the valve portion 23b is substantially equal to the exhaust gas inlet 6
The notch 23a is formed to have the same size as the inner diameter of a and the depth of the notch 23a is so large that the bottom 23c closes the exhaust gas inlet 5a. Further, an opening 23d is formed in each valve portion 23b located inside the bottom portion 23c, and a valve portion 23e is formed between each opening.

The movable plate 23 is formed with a hole 23f into which the shaft 24 having a pinion 24a formed at one end is fitted, and the spacer ring 25 is inserted through the shaft 24 to fix the fixed plate 2.
It is inserted into a hole 22c formed in the center of 2 and is rotatable with respect to the fixed plate 22. The movable plate 23 is placed at the home position at a position where the valve portion 23b overlaps with the fan-shaped valve portion 22b, and from this position, the valve portion 23b is located in the fan-shaped space 22a.
It is rotated to the position where it overlaps with.

A rack 26a formed on a movable rod 26 of an actuator (not shown) meshes with the pin-on 24a, and the shaft 24 is rotated by the movement of the rack 26a. When the temperature detected by the temperature sensor reaches the set temperature, the rod 26 operates according to the drive signal generated from the control device 16 shown in FIG.

According to this structure, when the valve portion 23b is at the home position, the valve portion 23e is located in the fan-shaped space 22a, so that the exhaust gas inlet port 5a.
The exhaust gas having a low temperature is guided from the cutout portion 23a to the exhaust gas inlet port 6a of the bypass passage through a part of the fan-shaped space 22a.

When the temperature of the exhaust gas rises and the temperature detected by the sensor reaches the set temperature, the shaft 26 is rotationally driven by the rod 26 and the movable plate 23 is rotated. Then, the valve portion 23e
Overlap with the fan-shaped valve portion 22b, and the valve portion 23b overlaps with the fan-shaped space 22.
The valve portion 23b and the fan-shaped valve portion 22b are located at a position a.
Thus, the exhaust gas inlet 6a is closed, and the opening 23d and the exhaust gas inlet 5a communicate with each other through the fan-shaped space 22a. Therefore, the exhaust gas with a high temperature is exhausted from the exhaust gas inlet 5
It is introduced from a into the purification passage 5 shown in FIG. 1 and purified by a catalyst.

In this way, the movable valve 2 is moved by the rod 26.
Since the exhaust gas is switched to the exhaust gas inflow ports 5a and 6a by rotating the valve 3, the number of actuators used for valve operation can be further reduced as compared with the first modification. In addition, by controlling the amount of movement of the rod 26, the opening of the fan-shaped space 22a and the notch 23a and the opening 23d can be adjusted by rotating the movable valve 23. The inflow amount of exhaust gas can be adjusted.

(Second Embodiment) In the second embodiment, as shown in FIG. 8, a pipe 27 extending upstream of the gas passage 3 is inserted in the center of a cylindrical catalyst 30, and the inside of the pipe is Two
It is used as a bypass passage 60. Near the exhaust gas inlet 60a and the exhaust gas inflow passage 5a of the bypass passage 60, ring-shaped valves 29A and 29B which are divided into upper and lower parts for opening and closing the exhaust gas inflow passage 5a and a half-moon type valve for opening and closing the exhaust gas inlet 60a. 28A and 28B are fixed orthogonally to the shafts 17D and 17B, respectively (see FIGS. 4 to 6).

Normally, the valves 29A and 29B are arranged so as to close the exhaust gas inflow passage 5a as shown in FIG.
A and 28B are placed at positions where the exhaust gas inlet 60a is opened, and by driving the actuators 15A and 15B,
Each is in the opposite position.

The actuators 15A and 15B have a shaft 17
D and 18D are connected to each other, and the drive signals from the control device 16 open the valves 29A and 29B and rotate the shafts 17D and 18D in the directions to close the valves 28A and 28B.

On the other hand, the exhaust gas inlet 6 of the bypass passage 6
A valve 31 is arranged near a. The valve 31 has a tongue shape, and is fixed to a support member 32 provided on the outer peripheral surface of the canister container 4 shown in FIGS. 9A and 9B, and a plurality of valves 31 are arranged at the inflow port 6a.

The support member 32 is made of a shape memory alloy,
Normally, as shown in FIG. 9 (a), it has a shape bent at an acute angle, and when it is heated to a certain temperature by the temperature of the exhaust gas flowing in the pipe, it is substantially vertical as shown in FIG. 9 (b). The characteristics are given so that it is displaced until.

That is, normally, the valve 31 is held in the open state, and when the exhaust gas reaches a certain temperature or higher, it acts as a drive member for holding the valve 31 in the closed state. The support member 32 is designed to be restored at a set temperature at which the actuators 15A and 15B are driven.

According to such a configuration, the temperature sensor 11
If the detected temperature of has not reached the set temperature, the valve 28A,
28B and 31, as shown in FIG. 8, the inflow passages 6a, 6
The exhaust gas is guided to the bypass passages 6 and 60 because it is in the position to open the 0a.

When the temperature detected by the temperature sensor 11 reaches the set temperature, the actuator 15A, 15B causes the shaft 14 to move.
D and 18D are rotated, valves 28A and 28B are closed, valves 29A and 29B are opened, and further, valve 31 is shown in FIG. 9 (a).
9B is changed to the position shown in FIG. 9B, and the exhaust gas is introduced into the purification passage 5. Although the tongue-shaped valve 31 is fixed to the support member 32 here, the support member 3
It is also possible to make 2 a tongue piece to form a valve member.

(Third Embodiment) In a third embodiment shown in FIG. 10, a plurality of catalysts 40 are radially divided at equal intervals in a plane orthogonal to the exhaust gas passage in a catalytic converter 90 communicating with the exhaust passage. Is formed as a purification passage 50, and a bypass passage 61 formed of a radial space is formed between the catalysts 40. Both the purification passage 50 and the bypass passage 61 are formed so as to penetrate the catalytic converter 90.

A rotary plate 34 as a switching valve is arranged upstream of the catalytic converter 90. This rotating plate 3
4, the openings 40a and the fan-shaped valve portions 34b corresponding to the catalyst 40 and the bypass passage 61 are radially formed at equal intervals.

The rotary plate 34 is formed with a hole 34c in which the shaft 33a provided in the lever 33 is fixed. The shaft 33a is rotatable in a hole 90a provided in the center of the catalytic converter 90. Supported. The rotating plate 34 is usually
The fan-shaped valve portion 34b is placed at a position where it overlaps with the catalyst 40.

An actuator (not shown) is connected to the hole 33b provided at the base end of the lever 33. This actuator is connected to the control means 16 shown in FIGS. 1 and 8, and when the temperature detected by the temperature sensor exceeds a set temperature, the lever 33 is driven to rotate the rotary plate 34 and bypass the fan-shaped valve portion 34b. It is located on the passage 61.

According to this structure, when the detected temperature is equal to or lower than the set temperature, the fan-shaped portion 34b and the catalyst 40 are polymerized, so that the purification passage 50 is closed and the temperature is low through the opening portion 34a. That is, the exhaust gas during idling flows into the bypass passage 61.

When the temperature detected by the sensor reaches the set temperature even if the exhaust gas temperature rises, the lever 33 is driven by the actuator to rotate the rotary plate 34, and the fan-shaped valve portion 34b.
By this, the bypass passage 61 is closed, the opening portion 34a faces the catalyst 40, and the exhaust gas having a high temperature is introduced into the purification passage.

[0056]

As described above, according to the present invention, since the inflow of exhaust gas having a low temperature at the time of idling into the catalyst is extremely reduced, the amount of hydrocarbons accumulated in the catalyst can be reduced.
This will reduce the generation of white smoke during sudden acceleration.

The first passage for holding the catalyst in the bypass passage
Since it is provided integrally with the member, the temperature of the exhaust gas that passes through the bypass passage is transmitted to the catalyst, so the catalyst is preheated, and the rise time until the catalyst reaches the activation temperature is shortened. To be done. Therefore, the purification action when the exhaust gas flows into the catalyst is performed earlier, which leads to an improvement in purification efficiency.

Further, since the bypass passage is provided in at least one of the inside and the outer periphery of the first member holding the catalyst, the bypass passage can be formed without increasing the size of the exhaust gas purification device, and therefore the vehicle mountability is improved. Does not decrease.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic height Ise of an exhaust emission control device of the present invention.

FIG. 2 is a side sectional view showing the first embodiment of the exhaust emission control device of the present invention.

3 (a) is a perspective view showing a closed state of a valve member used in the exhaust emission control device shown in FIG. 2, and FIG. 3 (b) is (a).
4 is a perspective view showing an open state of the valve member shown in FIG.

FIG. 4 is a perspective view showing a modified example of the valve member in the first embodiment.

5 is a perspective view showing an initial state of the valve member shown in FIG.

6A is a cross-sectional view showing an initial state of a valve member which is a modified example of the valve member shown in FIGS. 4 and 5, and FIGS.
FIG. 6A is a cross-sectional view showing an operating state of the valve member shown in FIG.

FIG. 7 is a perspective view showing a modified example of the valve member in the first embodiment.

FIG. 8 is a side sectional view showing a configuration of an exhaust emission control device showing a second embodiment of the present invention.

9A is a side sectional view showing an initial state of a valve and a driving member used in the second embodiment, and FIG. 9B is a side sectional view showing an operating state of the valve and the driving member shown in FIG. 9A. It is a figure.

FIG. 10 is a perspective view showing a main part of a third embodiment of the present invention.

FIG. 11 is a diagram showing the characteristics of the catalyst used in the present invention.

[Explanation of symbols]

E Engine 1 Exhaust gas purification device 2 Exhaust gas passages 3, 30, 40 Catalyst 4 First member (canister container) 5 Purification passage 6 Bypass passage 7 Second member (housing) 8 Opening / closing mechanism 5a, 6a, 60 Exhaust gas inlet 11 Temperature sensor 16 Control means 12 (A, B), 29 (A, B) First on-off valve 13, 17 (A, B), 31 Second on-off valve 22 Fixed plate 23 Moving plate 32 Driving member 34 Rotating plate 34a Open Hole

Claims (7)

[Claims] 1. A purifying passage configured by a first member for holding a tubular catalyst provided in an exhaust passage for exhaust gas discharged from an engine, and at least one of an inside and an outer periphery of the first member. A second member that is integrally provided in the first member and forms a bypass passage that bypasses the first member; and a purification passage in the first member that is closed when the temperature of the exhaust gas is lower than a set temperature, and An opening / closing mechanism is provided which opens and closes the high-pass passage formed by two members, opens the purification passage when the temperature of the exhaust gas is equal to or higher than a preset temperature, and closes the bypass passage formed by the second member. Exhaust gas purification device. 2. The opening / closing mechanism comprises a valve member for opening / closing the exhaust gas inlet of the first member and the second member, and a drive member made of a shape memory alloy for opening / closing the valve member at the set temperature. The exhaust emission control device according to claim 1. 3. A valve for opening / closing an exhaust gas inlet of each of the first member and the second member, wherein the opening / closing mechanism is provided upstream of the catalyst in the exhaust passage and detects a temperature of exhaust gas. The exhaust emission control device according to claim 1, further comprising: a member and a control unit that controls opening and closing of the valve member based on a temperature detected by the temperature sensor. 4. The valve member includes a first opening / closing valve provided at an exhaust gas inlet of the first member and a second opening / closing valve provided at an exhaust gas inlet of the second member. The exhaust emission control device according to claim 2, which is characterized in that. 5. The valve member is composed of a fixed plate having apertures respectively provided at exhaust gas inlets of the first member and the second member and a rotatable movable plate. The exhaust emission control device according to claim 2 or 3. 6. The valve member comprises first and second butterfly valves provided at exhaust gas inlets of the first member and the second member respectively, and the first and second butterfly valves are provided. The exhaust emission control device according to any one of claims 2 to 3, wherein the exhaust gas purification devices are connected by changing their phases by 90 °. 7. A plurality of catalysts provided in an exhaust passage for exhaust gas of an engine, and arranged in a plane orthogonal to the exhaust passage so as to be divided radially at equal intervals, and a plurality of radials formed between the catalysts. A catalyst converter that forms a bypass passage that bypasses the catalyst and that is formed by a gap between the catalyst, a temperature sensor that is provided upstream of the catalyst converter in the exhaust passage, and detects the temperature of the exhaust gas, the catalyst and the bypass passage. A valve member provided at the exhaust gas inflow port of the rotary plate having an opening corresponding to the catalyst and the gap, and the catalyst when the temperature of the exhaust gas detected by the temperature sensor is lower than a set temperature. Close and open the bypass passage, open the catalyst when the temperature of the exhaust gas is equal to or higher than the set temperature, and close the bypass passage. The exhaust gas purification apparatus characterized by comprising a control means for controlling opening and closing the valve member.