JP2557139Y2 - Catalytic converter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter used for an exhaust system of an automobile engine.

[0002]

2. Description of the Related Art An example of a conventional catalytic converter is disclosed in Japanese Utility Model Laid-Open Publication No. 52-135713. In this vehicle, a main catalyst is disposed in a main exhaust passage of an engine of a vehicle, a bypass passage is provided upstream of the main catalyst, an auxiliary catalyst is provided in the bypass passage, and a switching valve is provided to open and close the bypass passage. It has a configuration. Then, by operating the switching valve, the exhaust gas is caused to flow to the main catalyst via the auxiliary catalyst or directly to the main catalyst.

[0003]

By the way, in the above-mentioned catalytic converter, the catalyst is mainly poisoned by lead or the like in the upstream portion, while the poisoning amount is smaller in the downstream portion than in the upstream portion. As a result, the purification performance as a whole tended to be biased. For this reason, the fact is that the catalyst has not been fully utilized in proportion to its capacity.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a catalytic converter capable of achieving uniform purification performance and effective use in accordance with the capacity.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a catalyst core provided in an exhaust passage of an engine.
In the inverter, upstream and downstream of the catalytic converter
A branch portion and a collecting portion respectively provided in the flow side, the branch
First and second passages respectively connected to the part and the collecting part
And one end communicates with the branch portion, and the other end communicates with the gathering portion.
A bypass passage communicating downstream of the
One end side opening / closing and the exhaust passage and the front at the branch portion
The bypass passage is capable of communicating with or blocking the second passage.
When one end of the exhaust port is closed,
A first valve mode that communicates a passage with the second passage;
When one end of the bypass passage is opened,
Valve for shutting off the exhaust passage and the second passage
A first valve which is an embodiment, and a downstream side of the collecting portion.
In the portion of the exhaust passage upstream of the bypass passage
The exhaust passage on the downstream side is connected and blocked, respectively.
Communication, a second valve having a shut-off valve mode ,
The first and second valves are linked in accordance with the exhaust gas temperature,
The first valve is in a first valve mode and the second valve is connected.
The valve is in the valve first switching state in the valve passing mode, or the valve is in the first switching state.
Is a second valve mode and the second valve is a shutoff valve mode
Is selectively switched to the valve second switching state .

[0006]

With such a configuration, for example, when the exhaust gas temperature is
By setting the valve to the first switching state when it is higher than
The first valve is in the first valve mode (one end of the bypass passage).
Is closed, and the exhaust passage and the second passage
Communication state) and the second valve is in a communication valve mode.
And the upstream portion of the exhaust passage, the branch portion,
1, the second passage, the collecting section, and the exhaust passage on the downstream side in this order.
An exhaust passage through which air flows is formed, and the first and second passages are in contact with each other.
In the medium, the direction from the branching part to the collecting part (forward direction)
Exhaust flows in the direction. In addition, when the exhaust temperature is
In this case, the first valve is switched by setting the valve to the second switching state.
The valve is in the second valve mode (one end of the bypass passage is opened,
The state where the exhaust passage and the second passage are cut off at the fork
State), and the second valve is in a shut-off valve mode.
The upstream part of the passage, the branch, the first passage, the collecting part, the second
Passage, branch section, bypass passage and downstream exhaust passage
An exhaust system path in which exhaust flows in order is formed.
For the catalyst of the road, the direction from the collecting part to the branch part (reverse direction)
Exhaust flows through.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes an exhaust passage provided in an exhaust system of an engine (not shown). Exhaust passage 1
Is a first main pipeline (upstream portion of the exhaust passage) which is arranged at a certain distance upstream and downstream of the exhaust system, respectively.
The first and second main pipes (downstream exhaust passages) 3 and the first main pipe so that the upstream opening 5a communicates with the first main pipe side wall opening 4 formed on the side wall of the first main pipe 2. And an auxiliary pipeline 5 provided side by side with the channel 2. A second main conduit side wall opening 6 is formed in a side wall of the second main conduit 3. The second main conduit side wall opening 6 communicates with the first main conduit side wall opening 4 of the first main conduit 2 to bypass the second main conduit side wall opening 6. A passage 7 is provided. In this case, the downstream opening 2a of the first main pipeline 2 is connected to the second opening 2a.
And the downstream opening 2a of the first main pipeline 2 and the downstream opening 5b of the auxiliary pipeline 5 are set to be flush with each other. I have.

A catalyst 8 is provided so as to be connected to the downstream opening 2a of the first main line 2, the downstream opening 5b of the auxiliary line 5, and the upstream opening 3a of the second main line 3. This catalyst 8
Accommodates the catalyst carrier 10 in the catalyst case 9 and
0, the catalyst carrier 10 penetrates through the catalyst carrier 10,
The configuration is such that a partition 11 that partitions the second catalyst carriers 10a and 10b is provided. As described above, by disposing the catalyst 8, the exhaust passage 1 is separated from the partition 11.
As a result, the first and second passages 1a and 1b are defined, and the first and second catalyst carriers 10a and 10b are arranged in the first and second passages 1a and 1b, respectively.
In this case, the openings on one side of the first and second passages 1a and 1b are flush with each other, and the downstream opening 2a of the first main conduit 2 and the downstream opening 5b of the auxiliary conduit 5 respectively. On the other hand, the other sides of the first and second passages 1a and 1b communicate with each other and open to the common opening 8a, and the common opening 8a is located on the upstream side of the second main conduit 3. It is overlaid on the opening 3a. In this embodiment, the catalyst case 9
The connection portion of the second main line 3 with the main line 3 constitutes a collecting portion. Ma
In this embodiment, the auxiliary conduit 5 and the second passage 1b are
A first main conduit 2 and an auxiliary pipe constituting a second passage of the invention;
The road 5 forms a branch.

A first valve 12 which is operated by an electric actuator is provided at a portion of the first main line 2 on the upstream side of the first main line side wall opening 4. The first valve 12 is in a state in which the upstream opening 7a of the bypass passage 7 is closed as shown in FIG. 1 (first valve mode), and as shown in FIG. 3, the first main pipe side wall of the first main pipe 2 The valve opening / closing operation is selectively switched to a state in which the opening 4 is closed (second valve mode) .

The second main conduit side wall opening 6 of the second main conduit 3
The portion of the bypass passage 7 on the upstream side of the downstream opening 7b is operated by an electric actuator to open and close (communicate and shut off) the exhaust passage 1 (the respective states correspond to the communication and shutoff valve modes). Construct) Second valve 1
3 are provided.

At the outlet of the catalyst 8, a temperature sensor (not shown) is provided to detect the exhaust gas temperature. A controller (not shown) is provided connected to the temperature sensor, the first valve 12 and the second valve 13. This controller sets the first and second valves 12 and 13 as shown in FIG. 3 at the time of cold start such as in the initial setting state or after a long time stop, and closes the exhaust passage 1 by the second valve 13. In addition, the first main pipeline side wall opening 4 of the first main pipeline 2 is closed by the first valve 12 (the valve second switching state).
To), exhaust from the engine, the first catalyst support 10a
After passing through, the second catalyst carrier 10
And returns to the side, passes through the second catalyst carrier 10b, and then forms a circuit for discharging through the bypass passage 7. Also,
After the start, when the exhaust gas temperature reaches, for example, 500 ° C. (in a normal use state), the setting of the first and second valves 12 and 13 is switched as shown in FIG. 1 by a signal from the temperature sensor. That is, while the upstream opening 7a of the bypass passage 7 is closed by the first valve 12, the second valve 13 is opened (the valve is switched to the first switching state) , and the exhaust from the engine is discharged to the first and second valves. Catalyst carriers 10a, 10b
, And then discharged from the common opening 8a.

The operation of the catalytic converter configured as described above will be described below for a normal use state and a cold start state. In normal use, first, as the second valve 12 and 13 shown in FIG. 1 as described above the valve
The first switching state is set. When the exhaust gas is sent from the engine, the exhaust gas is converted into the first and second catalyst carriers 10a and 10a.
b in parallel and in the forward direction, and thereafter discharged from the common opening 8a to the second main pipeline 3 side. In this case, the cross-sectional area of the catalyst carrier 10, that is, the cross-sectional area of the catalyst flow path is wider than the cross-sectional area of the first main pipe 2 or the second main pipe 3, so that the exhaust pressure is reduced accordingly. When the upstream portion F, F of the catalyst carrier 10 is compared with the downstream portion R, R, the upstream portion F, F is poisoned with lead or the like, while the downstream portion R, R is poisoned with lead or the like. , R, the upstream part F,
The poisoning amount is smaller than that of F, and a high active state is maintained.

In a cold start state after a long stop,
The first and second valves 12, 13 are set to the valve second switching state by the controller as shown in FIG. When exhaust gas is sent from the engine, the exhaust gas passes through the first passage 1a (first catalyst carrier 10a), is returned by the second valve 13, and is returned to the second passage 1b (second catalyst carrier). 10b), and is discharged to the second main pipeline 3 side via the bypass passage 7. In this case, since the exhaust gas does not expand adiabatically at the inlet of the catalyst 8, the catalyst carrier 10 comes into contact with the higher temperature exhaust gas. Therefore, the catalyst carrier 1
0 is raised in a short time, the activation time of the catalyst carrier 10 is shortened, and the purification rate is improved. Further, as described above, in the normal use state, the first and second catalyst carriers 10a and 10a
The downstream portions R, R of b are maintained in a high active state. Therefore, the exhaust gas is appropriately purified by the exhaust gas flowing in the reverse direction in the downstream portion R of the second catalyst carrier 10b (that is, the purification performance is improved). In the above-described conventional catalyst, only the upstream portion mainly exerts the purifying action of the exhaust gas, and the portion exhibiting the purifying action as a whole catalyst is biased. As described above, the downstream portion R of the second catalyst carrier 10b also greatly contributes to the purification of exhaust gas, so that the purification performance of the entire catalyst 8 can be made uniform and effective utilization corresponding to the capacity can be achieved.

By changing the catalyst case 9 of the above-described catalyst 8, it is possible to variously change and set the catalyst shape, the catalyst arrangement, and the like.

When a one-block catalyst carrier monolith is to be used, a partition 15 is provided in close contact with the catalyst carrier monolith 14, as shown in FIGS. 5 and 6, for example.
By providing the catalyst carrier monolith 14 provided with the partition 15 in the exhaust passage, it can be applied in the same manner as in the above-described embodiment.

The shape of the partition is not limited to the above-mentioned one, but may be, for example, a hollow partition 16 provided through the catalyst 8 as shown in FIG.

[0017]

[Effect of the Invention] Since the present invention is a catalytic converter configured as described above, the first and second valves are set to the exhaust temperature.
Switch to valve first switching state and valve second switching state accordingly
By setting, the exhaust gas flowing through the catalyst in the second passage is set.
Direction is switched between forward and reverse, and exhaust
When flowing, the catalyst-side portion of the catalyst in the second passage is
Positive amount of poisoning compared to the branch side part and high active state
If the exhaust gas flows in the opposite direction,
Because the side part is maintained in a high active state, the entire catalyst and
It is possible to maintain the high active state almost uniformly
Effective use that matches the capacity of the catalyst
Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a normal use state of a catalytic converter according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a flow of exhaust gas in the normal use state.

FIG. 3 is a cross-sectional view illustrating a cold start state of the catalytic converter according to the embodiment of the present invention;

FIG. 4 is a sectional view showing a flow of exhaust gas in the cold start state.

FIG. 5 is a sectional view showing a catalyst carrier monolith used in a catalytic converter.

FIG. 6 is a plan view showing the catalyst carrier monolith.

FIG. 7 is a sectional view showing different types of catalyst partitions.

[Explanation of symbols]

 Reference Signs List 1 exhaust passage 1a first passage 1b second passage 7 bypass passage 7b downstream opening 8 catalyst 12 first valve 13 second valve

Claims (1)

(57) [Scope of request for utility model registration] A catalyst core provided in an exhaust passage of an engine.
In the inverter, provided upstream and downstream of the catalytic converter, respectively.
And the first and second communicating parts respectively connected to the branching part and the collecting part.
The passage has one end communicating with the branch portion and the other end below the collecting portion.
A bypass passage communicating with the flow, an opening / closing at one end of the bypass passage, and
Communication between the exhaust passage and the second passage can be cut off
When the one end of the bypass passage is closed, the branch
Communicating the exhaust passage and the second passage in the section
In the first valve mode, one end of the bypass passage is opened.
In some cases, the exhaust passage and the second passage in the branch portion
A first valve in a second valve mode for shutting off a passage, and the bypass in an exhaust passage downstream of the collecting portion
An exhaust passage provided at a portion upstream of the passage,
Communication and shut-off valves to perform communication and shut-off, respectively.
A second valve, wherein the first and second valves are linked in accordance with the exhaust gas temperature,
The first valve is in a first valve mode and the second valve is connected.
The valve is in the valve first switching state in the valve passing mode, or the valve is in the first switching state.
Is a second valve mode and the second valve is a shutoff valve mode
Wherein the valve is selectively switched to the valve second switching state .