JP2003239730A - Exhaust emission control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accelerate purification of an exhaust gas by early activating a catalyst immediately after engine starting. <P>SOLUTION: Partition plates which respectively divide into two an inlet side end face part and an outlet side end face part of a catalyst carrier are inserted into a catalyst case carrying the catalyst carrier. A first opening/closing valve, a second opening/closing valve each of which opens/closes divided one side, and a third opening/closing valve which is driven to open/close in the middle of a return passage for making an opening of an inlet side and an opening of an outlet side of the catalyst carrier communicate with each other, are controlled to open/close based on an engine operating condition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an engine mounted on an automobile or the like,
Particularly, it relates to improvement of early activation of the catalytic converter when the engine is cold.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for purifying exhaust gas of an automobile engine, an exhaust gas purifying apparatus using a carrier carrying a precious metal as a catalyst has been known. In order to purify harmful components in exhaust gas using such a noble metal catalyst, it is generally necessary to raise the temperature of the catalyst to its activation temperature of about 350 ° C. or higher. However,
Immediately after the engine is started, the catalyst carrier does not reach the activation temperature, so that there is a problem that exhaust gas harmful components such as hydrocarbon compounds (hereinafter abbreviated as HC) are discharged to the atmosphere without being purified. .

In order to solve such a problem, in the exhaust gas purifying apparatus described in Japanese Patent Application Laid-Open No. 8-14034, the catalyst device 4 (three-way catalyst containing a precious metal as a main component), which has the main function of purifying exhaust gas, is used. An adsorption device 5 for adsorbing harmful components of exhaust gas (having a cordierite honeycomb body 12 supporting a hydrophobic zeolite as an adsorbent structure) is provided downstream, and the honeycomb body 12 is provided on the side thereof. The bypass flow path 5b is formed, and the switching valve 8 is provided upstream of these, and immediately after the engine is started, the switching valve 8 is opened to adsorb HC to the adsorbent, while the switching valve 8 is opened when the exhaust gas temperature rises. By closing the valve, the adsorbed component which has become high temperature due to the heat of the exhaust gas is desorbed and is recirculated to the upstream side of the catalyst device 4 through the recirculation flow paths 10 and 14.

However, in this device, the adsorption device 5 is required in addition to the catalyst device 4, the device becomes complicated, and the cost increases. Also, the exhaust gas pressure is the exhaust manifold 2
Since the inside of the exhaust gas is the highest, and it gradually decreases due to the pressure loss due to passing through the catalyst device 4 and the adsorption device 5, the exhaust gas recirculating through the recirculation flow paths 10 and 14 is small, and the HC in the exhaust gas is not purified. There is.

Further, in the exhaust system disclosed in Japanese Patent Laid-Open No. 7-77034, a catalytic converter 11 extending in the longitudinal direction of the engine is arranged below the exhaust manifold branch pipe 9a, and a bypass pipe 21 extending downward from the upstream pipe 9c is used as a catalyst. When the engine 11 is warmed up, the flow path switching valve 22 is controlled to guide the exhaust gas into the catalytic converter 11 through the bypass pipe 21, while the engine 11 is warmed up. Is controlled to guide the exhaust gas into the catalytic converter 11 through the exhaust manifold collecting portion 9B and the exhaust gas introducing portion 10. However, according to this device, the exhaust gas from the outlet of the bypass pipe 21 and the exhaust gas from the outlet of the exhaust gas introduction pipe 10 both pass through the entire catalyst of the catalytic converter 11, and the exhaust gas becomes the catalyst when the engine is warmed up. Since it passes through the whole, there is a problem that it takes time to activate the catalyst.

Further, in the exhaust gas purification apparatus described in Japanese Patent Laid-Open No. 9-203314, the main passage 31a is provided upstream of the exhaust pipe 31.
A valve 33 for branching to the bypass passage 31b and installing a catalyst in the main passage 31a and switching the flow of exhaust gas is provided. When the catalyst is inactive and the air-fuel ratio is rich by the determination means 34, the switching valve is switched so that the exhaust flows to the catalyst 32 side and the exhaust flows to the bypass passage 31b side under other conditions. However, this apparatus has a problem that two catalysts are required and catalyst warm-up becomes slow.

[0007]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an exhaust gas purifying apparatus that promptly activates a catalyst immediately after starting an engine to promote purification of exhaust gas.

In order to achieve the above object, an exhaust gas purifying apparatus according to claim 1 of the present invention comprises a catalyst case carrying a catalyst carrier, an inlet side end face portion and an outlet of the catalyst carrier. A partition plate that divides the side end surface portion into two is provided, and first and second opening / closing valves that open and close one side of the divided two by an actuator, and a return passage that connects the inlet side passage and the outlet side passage of the catalyst carrier. And a third opening / closing valve which is opened / closed by an actuator, and the opening / closing of the first, second and third opening / closing valves is controlled based on the engine operating state.

According to the present invention, the total passage area of the catalyst carrier is divided into two by the partition plate so that the exhaust gas is returned. Therefore, when the engine is started, the exhaust gas is completely exhausted to one side of the catalyst carrier. Since the amount of gas passes through, it can be warmed up early, and the remaining heat warms up the catalyst carrier on the other side, so the catalyst carrier is warmed up about twice as fast as the catalyst carrier as a whole. The catalyst activation temperature (about 350 ° C.) can be reached quickly, and the emission of harmful components can be suppressed early.

According to a second aspect of the present invention, when the engine water temperature is equal to or lower than a predetermined value, the first and second opening / closing valves are closed and the third opening / closing valve is opened, so that the catalyst carrier After passing through one side of the entire passage area and passing through the other side, when the engine water temperature is equal to or higher than a predetermined value, the first and second opening / closing valves are opened and the third opening / closing valve is closed. It is characterized in that it passes through the entire passage area of the catalyst carrier.

According to the present invention, immediately after the engine is started, when the engine water temperature is equal to or lower than the predetermined value, the first and second
The on-off valve is closed and the third on-off valve is opened to circulate the exhaust gas to warm up one side of the catalyst carrier, and the residual heat warms up the other side of the catalyst carrier so that the engine water temperature exceeds a predetermined value. When this happens, exhaust gas is made to pass through the entire passage area of the catalyst carrier, so the warm-up speed of the catalyst carrier is about twice as fast as in the conventional technology, and the optimum activation temperature state is maintained without excessive heating. Can be maintained.

According to a third aspect of the present invention, when the cooling water temperature of the engine is equal to or higher than a predetermined value and the intake air amount is equal to or lower than the predetermined value, the first and second opening / closing valves are closed, and 3 Open the on-off valve, pass through one side of the catalyst carrier, and then return through the return pipe to pass through the other side. When the engine water temperature is equal to or higher than a predetermined value,
When the intake air amount is equal to or larger than a predetermined value, the first and second opening / closing valves are opened and the third opening / closing valve is closed so that the entire passage area of the catalyst alone is passed.

According to the present invention, when the engine water temperature is equal to or higher than a predetermined value and the exhaust gas amount is small even when the catalyst carrier reaches the activation temperature, such as during idling, the exhaust gas is returned to the catalyst. By maintaining one side of the carrier at the activation temperature, it is possible to maintain the optimum activation temperature state even if idling continues for a long time.

The invention according to claim 4 of the present invention includes the first and second valve bodies that open and close one side of each of the pipelines and the second valve body that opens and closes each opening communicating with the return passage. Depending on the operating condition of the engine, the second on-off valve
Exhaust gas passes through one side of the catalyst carrier, returns through the return passage and passes through the other side of the catalyst carrier, or exhaust gas passes through the entire passage area of the catalyst carrier without returning through the return passage. Is characterized by.

According to the present invention, openings are provided at the upstream side and the downstream side of the catalyst case carrying the catalyst carrier, the openings are communicated with the return passage, and the openings and the pipelines are provided by the first and second opening / closing valves. By simultaneously switching between open and closed, the third on-off valve can be omitted as compared with the first to third aspects, so that the structure is simplified and the manufacturing cost can be reduced.

According to a fifth aspect of the present invention, when the engine water temperature is equal to or lower than a predetermined value, the first and second opening / closing valves are closed and the exhaust gas passes through one side of the catalyst carrier.
When the engine water temperature is equal to or higher than a predetermined value, the first and second return pipes are returned to pass the other side.
It is characterized in that the on-off valve is opened to pass the entire passage area of the catalyst carrier.

According to the present invention, immediately after the engine is started, when the engine water temperature is equal to or lower than the predetermined value, the first and second opening / closing valves are closed to return the exhaust gas to warm up one side of the catalyst carrier, Since the catalyst carrier on the other side is warmed up by the residual heat, the structure can be simplified and the manufacturing cost can be reduced, as compared with the first to third aspects, because the third on-off valve can be omitted.

According to a sixth aspect of the present invention, when the engine water temperature is equal to or higher than a predetermined value and the intake air amount is equal to or lower than the predetermined value, the first and second opening / closing valves are closed, and the exhaust gas is discharged. The gas passes through one side of the catalyst carrier and then returns through the return pipe to pass through the other side of the catalyst carrier. When the intake air amount is equal to or more than a predetermined value, the first and second opening / closing valves are opened. It is characterized in that the catalyst passes through the entire passage area of the catalyst carrier.

According to the present invention, when the engine water temperature is equal to or higher than a predetermined value and the intake air amount is smaller than the predetermined value, the exhaust gas is maintained at the activation temperature on one side of the catalyst carrier, so that idling continues for a long time. Since the emission of harmful components of the exhaust gas can be maintained to be reduced, the structure can be simplified because the third on-off valve can be omitted as compared with the first to third aspects.
Manufacturing costs can also be reduced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] A preferred first embodiment of the present invention will be described with reference to the drawings. Figure 1
5 to 5 show the exhaust gas control device according to the embodiment of the present invention. FIG. 1 shows the entire exhaust gas control device.
An exhaust manifold 2 is connected to an exhaust port of an engine 1 having a plurality of cylinders, and an exhaust pipe line 3 is connected downstream thereof. A catalytic converter 4 is connected downstream of the exhaust pipe line 3, and a silencer 5 is connected further downstream thereof. The exhaust gas discharged from the engine 1 passes through the exhaust pipe line 3, the catalytic converter 4 purifies harmful components, and is discharged to the atmosphere via the silencer 5. Oxygen sensors 6 and 7 are attached to the upstream side and the downstream side of the catalytic converter 4, respectively, to detect HC, CO, and NOx concentrations in the exhaust gas, and the signals thereof are sent to an electronic control unit (ECU) 8 including a microcomputer. Sent. Motors 16, 17, and 19 described later are incorporated in the catalytic converter 4, and the EC
It is controlled by the drive signal from U8. Electronic control unit (EC
U) 8 corresponds to the control means in the claims.

On the other hand, an intake manifold 9 is connected to an intake port of the engine 1, and a throttle body 10 for controlling the intake air amount, that is, an intake air amount controller is arranged upstream of the intake manifold 9 and driven by the ECU 8. It is driven based on the signal. Further, an air flow meter 11 for measuring the amount of intake air is arranged upstream thereof, and a signal thereof is sent to the ECU 8. Water temperature sensor 12 is engine 1
The temperature of the cooling water circulated inside the engine 1 is detected and sent to the ECU 8. Based on these signals, the ECU 8 controls a motor (not shown) that controls the opening of a throttle valve (not shown) provided in the throttle body 10 to control the intake air amount.

Next, regarding the structure of the catalytic converter,
This will be described in detail with reference to FIGS. Catalyst case 13
Has a thick cylindrical body 20 at the center and has conical surfaces 21 and 22 at both ends, and a catalyst carrier 23 is carried inside the cylindrical body 20. Pipe lines 14, 15 are provided on the end faces of the conical faces 21, 22.
Are connected, and motors 16 and 17 for controlling opening / closing of a first opening / closing valve 26 and a second opening / closing valve 29, which will be described later, are attached to the pipelines 14 and 15, respectively. Also, catalyst case 1
An exhaust gas return passage 18 is provided in the upper part of the outer peripheral portion of 3, and a motor 19 for controlling the opening / closing of a third opening / closing valve 34 described later is provided in the middle thereof.

Shafts 24 and 27 are rotatably provided in the pipe lines 14 and 15 and are connected to the rotation shafts of the motors 16 and 17, respectively. The shafts 24 and 27 have a first
The valve body 25 and the second valve body 28 are fixed, respectively, and the rotation of the motors 16 and 17 shields one side or the other side corresponding to half of the total passage area of the pipelines 14 and 15. There is. Inlet-side end surface portion 2 of the catalyst carrier 23
3a and the outlet side end face portion 23b and the shafts 24 and 27, the partition plate 30 is formed so as to divide the exhaust passage of the conical surfaces 21 and 22 of the catalyst case 13 into upper passages 21b and 22b and lower passages 21a and 22a. 30 are provided. Catalyst carrier 23
Is provided with a plurality of small holes provided in the catalyst carrier 23 so as to penetrate therethrough in the axial direction, and by providing the partition plates 30, 30, the total passage area is divided into two.

Further, the conical surfaces 21 and 22 are provided with an opening 31 on the upstream side and an opening 32 on the downstream side, which communicate with each other through the exhaust gas return passage 18. The opening 31 is the partition plate 3.
It is opened to the lower passage 21a of the tubular body 20 which is divided by 0. The opening 32 opens in the upper passage 22b of the conical surface 22. In addition, the shaft 3 is provided at approximately the center of the return passage 18.
3 is pierced so as to be rotatable, and is connected to the rotation shaft of the motor 19. The shaft 33 has a substantially circular valve body 3
4 is fixed, and the return passage 18 can be opened and closed by the rotation of the motor 19. Further, flanges 36 and 37 are formed at both ends of the pipelines 14 and 15, and are connected to the exhaust pipeline 3 and the silencer 5 with bolts or the like. FIG. 3 shows the states of the first and second on-off valves after the engine has warmed up, and FIG. 4 shows the states of the first and second on-off valves immediately after the engine starts. Here, the actuator mentioned in the claims indicates a motor.

The operation of the above structure will be described with reference to the flowchart of FIG. When the ignition key switch of the engine 1 is turned on, the routine proceeds to step 100, where it is determined whether the water temperature of the engine 1 is 60 ° C. or lower. If affirmative (YES), proceed to step 110, first
The on-off valve 26 is driven by the motor 1 in response to a drive signal from the ECU 8.
6 is driven and rotated downward of the pipe line 14 to close the lower half of the pipe line 14. The second on-off valve 29 rotates the motor 17 in response to a drive signal from the ECU 8 to rotate to the upper passage of the conduit 15 to close the upper half of the conduit 15. The third opening / closing valve 35 is opened by the rotation of the motor 19 and is controlled so that all the exhaust gas can be returned.

When the engine 1 is started by driving a starter (not shown), H
The low-temperature exhaust gas containing a large amount of C and CO passes through the exhaust pipe line 3 and passes through the upper half of the catalyst carrier 23.

Further, since the second opening / closing valve 29 closes the upper passage of the pipe 15, the exhaust gas passes through the opening 32, returns to the return passage 18 and is discharged from the opening 31, and the lower passage of the catalyst carrier 23. It passes through and is released to the atmosphere via the silencer 5. Next, the routine proceeds to step 120, where it is determined whether the water temperature of the engine 1 has exceeded 60 ° C. At this point, the engine 1 has not been warmed up yet, the result is negative (NO), the process returns to step 110, and the state of step 110 is maintained. After a while, the engine 1 is warmed up by the combustion heat of the fuel and the temperature of the exhaust gas also rises. The catalyst carrier 23 is rapidly warmed by the heat quantity of the exhaust gas and the oxidizing action of HC and CO.

When the temperature of the catalyst carrier 23 starts to be activated (about 350 ° C.), the water temperature of the engine 1 becomes 60 ° C.
Will be exceeded. In step 120, the water temperature is 60 ℃
If it is affirmative (YES),
Proceeding to step 130, as shown in FIG.
17 is driven to open the first opening / closing valve 26 and the second opening / closing valve 29, and the motor 19 is driven to close the third opening / closing valve 35. Then, the exhaust gas does not pass through the return passage 18, passes through the entire passage area of the pipeline 14, passes through the entire passage area of the catalyst carrier 23, passes through the pipeline 15, and is discharged to the atmosphere through the silencer 5. . At this time, since the temperature of the catalyst carrier 23 is already activated as a whole, the temperature of the catalyst carrier 23 does not decrease even if exhaust gas is passed through the entire passage area of the catalyst carrier 23. Therefore, the exhaust gas can be purified early after the engine is started.

By the way, even when the engine water temperature is 60 ° C. or more, when the intake air amount is small, that is, when the idling operation is continued for a long time, the temperature of the catalyst carrier 23 may decrease with time and fall below the activation temperature. . As a countermeasure in this case, in step 100, it is judged whether the temperature of the engine cooling water is 60 ° C. or lower, and a negative (N
If it is O), the routine proceeds to step 140, where it is judged if the intake air amount is 5 g / sec or less.

If affirmative (YES), step 1
10, the first opening / closing valve 26 and the second opening / closing valve 29 are closed, and the third opening / closing valve 35 is opened. By doing so, the temperature of the catalyst carrier 23 can always be maintained at the activation temperature. Further, the intake air amount is, for example, 5 g / s
When it is determined that it is not less than or equal to ec, that is, negative (NO)
If so, the routine proceeds to step 130, where the first opening / closing valve 26 and the second opening / closing valve 29 are opened and the third opening / closing valve 35 is closed. At this time, the exhaust gas amount is sufficient and the catalyst carrier 2
The temperature of 3 does not drop below the activation temperature. Therefore, even if the idling operation after engine warm-up continues for a long time, the exhaust gas purification performance does not deteriorate.

[Second Embodiment] Next, a second embodiment of the catalytic converter will be described with reference to FIGS. 6 to 8. 6 is a schematic view of the catalytic converter, FIG. 7 is a vertical sectional view of the catalytic converter, FIG. 8 is a valve shape for switching the return passage, and FIG. 9 is an operation diagram of the on-off valve. The same components as those in the first embodiment are designated by the same reference numerals. The catalytic converter 40 includes a cylindrical body 43 having a thick central portion of a catalyst case 41.
And conical surfaces 44 and 45 are formed at both ends,
The catalyst carrier 23 is carried in the cylindrical body 43. A motor 16 and a motor 17 are provided in the exhaust pipe lines 14 and 15. A return passage 42 is provided on the outer peripheral portion of the catalyst case 41.

The shafts 24 and 27 are provided so as to penetrate the pipe lines 14 and 15, and are connected to the rotation shafts of the motors 16 and 17 so as to be rotatable. Partition plates 30 and 30 are fixed between the inlet side end face portion 23a and the outlet side end face portion 23b of the catalyst carrier 23 and the shafts 24 and 25 to divide the total passage area of the pipe lines 14 and 15 and the catalyst carrier 23 into two. .

A return passage 42 for returning exhaust gas is provided on the outer peripheral surface of the catalyst case 41.
The catalyst case 41 is so constructed as not to be cooled by the traveling wind so as to cover the entire circumference thereof. Both end surfaces of the cylindrical body 43 are conical surfaces 44, 4
5, the upstream side opening 46 and the downstream side opening 47 are provided on the inclined surface. This opening 46,
Valve seats 48 and 49 are provided at 47. Shaft 24,2
A semi-circular first valve body 50, 53 for closing or opening one side of the pipe lines 14, 15 is fixed to the valve 5, and a disk-shaped second valve body 51, 54 is fixed to the other end. It is attached at an angle (120 to 150 °) with one valve body 50, 53.
The second valve body 5 is provided between the second valve body 51, 54 and the shaft 24, 25.
The width is smaller than the width of 1, 54, so that exhaust gas can easily pass through.

Next, the operation will be described in detail with reference to FIG. When the ignition key switch of the engine 1 is turned on, the routine proceeds to step 200, where the cooling water temperature of the engine is detected by the water temperature sensor 12, and the signal is EC
Send to U8. The ECU 8 determines whether the engine water temperature is 60 ° C. or lower, and if the determination is affirmative (YES), the process proceeds to step 210, where the second valve element 51, 54 is used to set the valve seat 4 as shown in FIG.
8, 49 are opened, the pipe line 14 closes the lower passage 44a by the first valve body 50, and the pipe line 15 opens the upper passage 45b by the first valve body 5.
By closing at 3, the exhaust gas passes through one side of the catalyst carrier 23, passes through the opening 47, returns through the return passage 42, is discharged from the opening 46, passes through the other side of the catalyst carrier 23, and passes through the pipeline 15. Then, the muffler 5 is discharged to the atmosphere.

Next, the routine proceeds to step 220, where it is judged whether or not the cooling water temperature of the engine 1 is 60 ° C. or higher, and affirmative (Y
If ES), the first valve bodies 50, 53 are opened, the second valve bodies 51, 54 are closed, and the exhaust gas passes through the entire passage area of the catalyst carrier 23 and is discharged to the atmosphere. Engine water temperature is 6
0 ° C. corresponds to the temperature at which the catalyst carrier 23 is activated. At this point, the catalyst carrier 23 has reached the activation temperature, and the exhaust gas can be purified by the entire catalyst carrier 23. Therefore, the number of on-off valves is one less than that of the first embodiment, the configuration is simple, and the cost can be reduced.

By the way, immediately after the engine 1 is just started, the exhaust gas temperature is low and the cooling water temperature of the engine 1 is also low. In step 220, it is determined whether the water temperature is 60 ° C. or higher, and if the result is negative (NO), step 21
0, the first valve bodies 50 and 53 are closed, and the second valve body 5
Keep 1,54 open. Further, in step 200, it is determined whether or not the cooling water temperature of the engine 1 is 60 ° C. or lower, and when the determination is negative (NO), the process proceeds to step 240, and the intake air amount is 5 g / sec or less. Is determined. When the result is affirmative (YES), that is, when it is determined that the vehicle is in the idling state, the routine proceeds to step 210, where the first valve bodies 50 and 53 are closed and the second valve bodies 51 and 54 are maintained open. This is a measure to prevent the temperature of the catalyst carrier 23 from decreasing due to a small amount of exhaust gas when the cooling water temperature of the engine 1 exceeds 60 ° C. because the amount of exhaust gas is small, and may fall below the activation temperature. .

In step 240, the intake air amount is 5 g / se
If it is determined to be negative (NO), the routine proceeds to step 230, where the first valve body 50,
53 is opened and the second valve bodies 51, 54 are closed, and the exhaust gas passes through the entire passage area of the catalyst carrier 23 and passes through the silencer 5. At this stage, the catalyst carrier 23 maintains the activation temperature and does not fall below the activation temperature by cooling. Therefore, in addition to the same effects as the first embodiment, the number of open / close valves is reduced by one, so that the structure is simple and the cost can be reduced. The motor in the embodiment is not limited to the motor and may be an electromagnetic solenoid or a rotary solenoid. Further, the return passage 42 may be partially configured without covering the entire catalyst case 41 as long as exhaust gas can return without resistance.

The present invention can be modified as follows within the scope not departing from the technical idea. That is, the return passage can be similarly opened and closed without any one of the second valve bodies 51 and 54 in the second embodiment, and the structure can be further simplified.

According to the configuration of the invention described in claim 1,
Since the catalyst carrier is divided into two and the exhaust gas is allowed to pass through, the catalyst carrier can reach the activation temperature early, and the exhaust gas concentration can be reduced early.

According to the second aspect of the invention, when the engine water temperature is lower than the predetermined temperature, the exhaust gas passes through one side of the catalyst carrier to warm up the catalyst carrier, and the engine water temperature is lower than the predetermined temperature. When it is high, it passes through the entire passage area of the catalyst carrier, so that the temperature of the catalyst carrier can be constantly controlled so as not to fall below the activation temperature.

According to the third aspect of the present invention, even if the engine is warmed up and idling continues for a long time, the temperature of the catalyst carrier is not lowered, and the emission of harmful components of the exhaust gas can be reduced. .

According to the configuration of the invention described in claim 4, in addition to the effects of claims 1 to 3, the structure can be simplified and the cost can be reduced because the third on-off valve can be omitted.

According to the structure of the invention described in claim 5, in addition to the effects of claims 1 to 3, the structure can be simplified and the cost can be reduced because the third opening / closing valve can be omitted.

According to the structure of the invention described in claim 6, in addition to the effects of claims 1 to 3, the structure can be simplified and the cost can be reduced because the third on-off valve can be omitted.

[Brief description of drawings]

FIG. 1 is an overall view of an exhaust gas purifying apparatus for an engine according to a first embodiment of the present invention.

FIG. 2 is an outline view of the catalytic converter according to the first embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of the catalytic converter according to the first embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view when the valve body of the catalytic converter according to the first embodiment of the present invention acts.

FIG. 5 is a flowchart for controlling the exhaust gas purification device according to the first embodiment of the present invention.

FIG. 6 is an external view of a catalytic converter according to a second embodiment of the present invention.

FIG. 7 is a vertical sectional view of a catalytic converter according to a second embodiment of the present invention.

FIG. 8 is a perspective view of an opening / closing valve according to a second embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view when a valve body of a catalytic converter according to a second embodiment of the present invention acts.

FIG. 10 is a flowchart for controlling an exhaust gas purification device according to a second embodiment of the present invention.

[Explanation of symbols]

1 engine 3 exhaust pipe 4,40 catalytic converter 8 Electronic control device (control means) 13,43 catalyst case 18 Return passage 23 Catalyst carrier 26 1st on-off valve 29 Second on-off valve 30 dividers 31, 32 openings 35 Third on-off valve 42 Return passage 46,47 opening 50,53 1st valve body 51,54 Second valve body 52 First on-off valve 55 Second on-off valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01N 3/28 F01N 3/28 H L

Claims (6)

[Claims] 1. An exhaust gas purifying device provided in an exhaust pipe of an engine, wherein the exhaust gas purifying device comprises a catalyst simple substance for purifying harmful components in exhaust gas, a central portion being thick, and both end portions being conical surfaces. A cylindrical catalyst case, an exhaust gas return passage that connects the inlet side opening and the outlet side opening of the inclined surface of the catalyst case with the outer peripheral portion of the catalyst case, and the inlet side end surface portion of the catalyst carrier And a partition plate which is respectively disposed on the end face portion on the outlet side and divides the entire passage area of the catalyst carrier and the pipeline into two parts. First and second opening and closing of the pipeline by driving an actuator on one side of the pipeline. A second on-off valve,
A third opening / closing valve that is opened / closed by an actuator provided in the middle of the return passage, and a control unit that controls the first, second, and third opening / closing valves, and according to an operating state of the engine, Exhaust gas passes through one side of the catalyst carrier and returns to the return passage and passes through the other side of the catalyst carrier, or exhaust gas passes through the entire passage area of the catalyst carrier without passing through the return passage. An exhaust gas purifying device for an engine, which is characterized in that 2. The operating state of the engine is such that when the engine water temperature is below a predetermined value, the actuator closes the first and second on-off valves and the actuator opens the third on-off valve, and exhaust gas is a catalyst carrier. After passing through one side, the return passage is returned to pass through the other side of the catalyst carrier, and when the engine water temperature is equal to or higher than a predetermined value, the first and second opening / closing valves are opened, and the first opening / closing valve is opened. 3. The exhaust gas purifying apparatus for an engine according to claim 1, wherein the on-off valve 3 is closed so as to pass through the entire passage area of the catalyst carrier. 3. The operating state of the engine is such that when the engine water temperature is equal to or higher than a predetermined value and the intake air amount is equal to or lower than a predetermined value, the first and second opening / closing valves are closed and the third opening / closing valve is closed. And the exhaust gas passes through one side of the catalyst carrier and then returns through the return passage to pass through the other side of the catalyst carrier. When the intake air amount is equal to or more than a predetermined value, the first and The exhaust gas purifying apparatus for an engine according to claim 2, wherein the second opening / closing valve is opened and the third opening / closing valve is closed so as to pass through the entire passage area of the catalyst carrier. 4. An exhaust gas purifying device provided in an exhaust pipe of an engine, wherein the exhaust gas purifying device comprises a catalyst carrier for purifying harmful components in the exhaust gas, and a thick central portion and inclined surfaces at both end portions. A cylindrical catalyst case, and an exhaust gas return passage that communicates the inlet side opening and the outlet side opening of the inclined surface provided at both ends of the catalyst case with the outer peripheral portion of the catalyst case, Partition plates that are respectively disposed on the inlet-side end face portion and the outlet-side end face portion of the catalyst carrier and divide the total passage area of the catalyst carrier into two parts; The first and second on-off valves integrally include a second valve body that opens and closes each of the openings communicating with the passage, and a control unit that controls opening and closing of the first and second on-off valves by an actuator. , The operating state of the engine Accordingly, the exhaust gas passes through one side of the catalyst carrier and returns through the return passage, passes through the other side of the catalyst carrier, or the exhaust gas does not pass through the return passage and the entire passage area of the catalyst carrier. An exhaust gas purifying device for an engine, characterized in that 5. The engine operating state is such that, when the engine water temperature is below a predetermined value, the actuator closes the first valve body and opens the second valve body, and exhaust gas passes through one side of the catalyst carrier. After that, the return pipe is returned to pass the other side of the catalyst carrier, or when the engine water temperature is equal to or higher than a predetermined value, the first valve body is opened and the second valve body is closed. The exhaust gas purifying apparatus for an engine according to claim 4, wherein the catalyst carrier passes through the entire passage area. 6. The operating state of the engine is such that when the engine water temperature is equal to or higher than a predetermined value and the intake air amount is equal to or lower than a predetermined value, the first valve body is closed and the second valve is closed.
After opening the valve element and passing one side of the catalyst carrier, the exhaust gas returns through the return pipe and passes through the other side of the catalyst carrier. The exhaust gas purifying apparatus for an engine according to claim 4, wherein one valve body is opened and the second valve body is closed so as to pass through the entire passage area of the catalyst carrier.