JP2009174342A - Catalytic converter with adsorption member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalytic converter 1 with adsorption member, improved in durability of the adsorption member. <P>SOLUTION: After the detachment of the adsorption member 2b is finished, a control part 14 opens a valve V1 of the main pipe 5, and on the other hand, a valve V2 of a bypass pipe 6 is closed, so that the total amount of exhaust from an engine a1 flows into the main pipe 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a catalytic converter with an adsorbing member.

Conventionally, there is a technology of a catalytic converter with an adsorbing member that accommodates an adsorbing member capable of adsorbing and desorbing hydrocarbons in exhaust gas and a catalyst carrier that is disposed in communication with the downstream side of the adsorbing portion and can purify exhaust gas. It is publicly known (see Patent Document 1).
JP 2006-194231 A

  However, the conventional invention has a problem that the durability of the adsorbing member is lowered because a part of the exhaust gas passes through the adsorbing member even after the adsorbing member is detached.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a catalytic converter with an adsorbing member that can improve the durability of the adsorbing member.

  In the first aspect of the present invention, a main body containing an adsorbing member capable of adsorbing / desorbing hydrocarbons in exhaust gas and a catalyst carrier arranged in communication with the downstream side of the adsorbing portion and capable of purifying exhaust gas; A main pipe that guides exhaust from the engine to the catalyst carrier, a bypass pipe that branches from the upstream side of the main pipe and leads the exhaust from the engine to the adsorbing member, and a downstream side of the branch position of the main pipe and bypass pipe Each of the valves is provided with a control unit capable of controlling the opening / closing operation of both valves, and the control unit is configured to operate the main pipe from when the engine starts until the adsorbing member reaches a separation temperature as the exhaust gas temperature rises. The valve of the bypass pipe is opened while the valve of the bypass pipe is opened, and the valve of the main pipe is opened while the catalyst carrier reaches the activation temperature from the desorption temperature of the adsorption member. ,the above Both the valves are opened until the adsorbing member finishes detachment after the medium carrier reaches the activation temperature. After the adsorbing member finishes detachment, the main pipe valve is opened while the bypass pipe is closed. The valve is in a closed state.

  In the first aspect of the invention, the control unit opens the valve of the main pipe while closing the valve of the bypass pipe after the adsorption member finishes detachment. Exhaust does not pass through the adsorption member via the bypass pipe, and the durability of the adsorption member can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
1 is an overall view showing an exhaust system of the first embodiment, FIG. 2 is a side view showing a catalytic converter with an adsorbing member of the first embodiment, FIGS. 3 to 6 are diagrams for explaining the operation of the first embodiment, and FIG. It is a figure which shows the experimental result explaining the effect of Example 1. FIG.

First, the overall configuration will be described.
As shown in FIG. 1, the exhaust system of the automobile of the first embodiment includes an engine a1, a catalytic converter a2, a catalytic converter 1 with an adsorbing member, a center muffler a3, and a rear muffler a4, connecting pipes b1 (exhaust manifold), b2 , B3, b4.

The catalytic converter a2 employs a metal catalyst carrier or a ceramic catalyst carrier (not shown) in a cylindrical main body, as well as known ones, and harmful components (HC, CO) in exhaust gas flowing from the engine a1 side. , Nox, etc.) are purified into harmless components (CO _2, H ₂ O, etc.) and discharged downstream.
A catalytic converter 1 with an adsorbing member, which will be described later, is provided on the downstream side of the catalytic converter a2.

As shown in FIG. 2, the catalytic converter 1 with an adsorbing member includes a main body 4 having an adsorbing portion 2 and a catalyst portion 3, a main pipe 5, a bypass pipe 6, and the like.
The adsorption part 2 is made of a metal-made cylindrical outer cylinder 2a and a columnar adsorption member 2b accommodated in the outer cylinder 2a.
The adsorbing member 2b is formed by coating an adsorbing material such as zeolite on the surface of a cell (not shown) formed through in the axial direction as in the known member.

A metal-made cylindrical shell 7 is connected to the upstream end of the outer cylinder 2a, and the upstream end of the shell 7 is closed by a substantially bowl-shaped end plate 8.
Thus, a chamber R1 is formed on the upstream side of the adsorption member 2b in the main body 4.
A metallic cylindrical shell 9 is connected to the downstream end of the outer cylinder 2a, and the outer cylinder 3a of the catalyst unit 3 is connected to the downstream end of the shell 9.

The catalyst unit 3 is made of a metal-made cylindrical outer cylinder 3a and a columnar catalyst carrier 3b accommodated in the outer cylinder 3a.
As the catalyst carrier 3b, a known metal catalyst carrier or a ceramic catalyst carrier is employed in the same manner as the catalyst carrier of the catalytic converter a2.
A diffuser 10 whose diameter is reduced toward the downstream side is connected to the downstream end of the outer cylinder 3a, and a flange 11 for connecting to the connecting pipe b3 is connected to the downstream end of the diffuser 10. Is fixed.
Thus, a chamber R2 is formed on the upstream side of the catalyst carrier 3b, and a partition member 12 is provided here.

The partition member 12 is made of metal and is formed in a substantially funnel shape, and a plurality of communication holes 12a are provided on the inclined surface.
The downstream end of the partition member 12 is disposed so as to cover the catalyst carrier 3b, and the downstream end of the main pipe 5 is connected to the upstream end in communication.

  A flange 13 for communicating with the connection pipe b2 is fixed to the upstream end of the main pipe 5, while the downstream end penetrates through the center of the end plate 8 and the suction member 2b to form the partition member 12. Are connected in communication with the upstream end of the.

  The upstream end of the bypass pipe 6 is connected in communication with the main pipe 5 branched from the upstream side, while the downstream end is connected in communication from the end plate 8 to the chamber R1.

Further, valves V1 and V2 are provided on the downstream side of the branch positions in the main pipe 5 and the bypass pipe 6, and the opening and closing operations of these valves V1 and V2 are controlled by the control unit 14.
The both valves V1, V2 of the first embodiment employ light and inexpensive butterfly valves.

The control unit 14 is electrically connected to the engine control unit 15 (ECU 15).
Furthermore, the control unit 14 is also electrically connected to temperature sensors 16 and 17 for detecting the surface temperature or the downstream atmosphere temperature of the adsorbing member 2b and the catalyst carrier 3b.
In addition, the joint portions of the metal component members described above are fixed by welding or the like not shown.

Next, the operation will be described.
In the catalytic converter 1 with the adsorbing member configured as described above, the control unit 14 starts from the start of the engine a1 based on the operating state of the engine a1 from the ECU 15 and the detection results of the temperature sensors 16 and 17, as shown in Table 1 below. Thus, the opening / closing operation of each valve V1, V2 is controlled.

(1) From the time of engine start until the adsorbing member reaches the separation temperature First, the valve V1 of the main pipe 5 is closed until the temperature of the exhaust gas rises from the time of engine startup until the adsorbing member 2b reaches the separation temperature, The valve V2 of the bypass pipe 6 is opened.
The separation temperature of the adsorption member 2b is generally 250 ° C. (= detection result of the temperature sensor 16) or higher.

As a result, as shown in FIG. 3, the entire amount of exhaust gas (shown by broken lines in the figure) is caused to flow from the bypass pipe 6 into the chamber R1, and then the adsorbing member 2b is passed.
After that, the exhaust gas that has passed through the adsorbing member 2b and has flowed into the chamber R2 is passed through the catalyst carrier 3b through the communication hole 12a of the partition member 12 in the chamber R2, and then discharged downstream.
At this time, the adsorbing member 2b adsorbs hydrocarbons in the passing exhaust gas.
Further, since the temperature of the exhaust gas is low, the catalyst carrier and the catalyst carrier 3b of the catalytic converter a2 do not function (see Table 1).

  Therefore, when starting the engine, it is possible to prevent the hydrocarbons in the exhaust from being released into the atmosphere while the catalyst carrier of the catalytic converter a2 and the catalyst carrier 3b are not functioning.

(2) Until the catalyst carrier reaches the activation temperature from the desorption temperature of the adsorption member Next, while the adsorption member 2b becomes the desorption temperature and the catalyst carrier 3b reaches the activation temperature, the valve V1 of the main pipe 5 is opened, The valve V2 of the bypass pipe 6 is closed.
The activation temperature of the catalyst carrier 3b is generally 350 ° C. or higher (= detection result of the temperature sensor 17).

As a result, as shown in FIG. 4, the entire amount of exhaust gas (shown by broken lines in the figure) is passed from the main pipe 5 to the catalyst carrier 3b and discharged downstream.
At this time, the catalyst carrier of the catalytic converter a2 is at the activation temperature, and the hydrocarbons in the exhaust gas can be purified by the catalyst carrier of the catalytic converter a2 (see Table 1).
Further, the partition member 12 can prevent a part of the exhaust gas from blowing back to the adsorption member 2b side.

(3) From the time when the catalyst carrier reaches the activation temperature until the adsorption member finishes detaching Next, from the time when the catalyst carrier 3b reaches the activation temperature until the adsorption member 2b finishes detachment, both valves V1, V2 are turned on. Both are open.
Note that the end of removal of the adsorbing member 2b is a predetermined time after the valve V2 is opened. Alternatively, it may be detected by providing a sensor for measuring the hydrocarbon concentration in the chamber R2 or by estimating the amount of hydrocarbon remaining in the adsorbing member 2b based on a signal from the ECU 15 as is well known. .

As a result, as shown in FIG. 5, the exhaust gas flows into both the bypass pipe 6 and the main pipe 5, passes through the catalyst carrier 3b, and then is discharged downstream.
At this time, the adsorbing member 2b separates the adsorbed hydrocarbons and discharges them downstream.
Further, in the catalyst carrier 3b, harmful components including the above-described hydrocarbons in the exhaust gas passing through the bypass pipe 6 and the main pipe 5 are purified to harmless components and then discharged downstream (see Table 1).

(4) After the adsorbing member finishes detaching Next, after the adsorbing member 2b finishes detaching, the valve V1 of the main pipe 5 is opened while the valve V2 of the bypass pipe 6 is closed.

As a result, as shown in FIG. 6, the entire amount of exhaust gas (shown by broken lines in the figure) passes through the main pipe 5 to the catalyst carrier 3b and is discharged downstream.
At this time, the hydrocarbons of the adsorbing member 2b are in an initial state where they are completely separated.
Further, in the catalyst carrier 3b, harmful components in the exhaust gas passing through the bypass pipe 6 and the main pipe 5 are purified into harmless components and then discharged downstream (see Table 1).

  Here, the conventional invention has a problem in that the durability of the adsorbing member 2b is deteriorated because part of the exhaust gas passes through the adsorbing member 2b even after the adsorbing member 2b has been detached. It was.

On the other hand, in the first embodiment, as described above, the valve a1 of the main pipe 5 is opened while the valve V2 of the bypass pipe 6 is closed after the adsorption member 2b has been detached, whereby the engine a1. Since the entire amount of exhaust gas from the exhaust gas flows into the main pipe 5, the exhaust gas does not pass through the adsorption member 2b via the bypass pipe 6, and the durability of the adsorption member 2b can be improved.
Moreover, the coating amount of the adsorption member 2b, such as zeolite, and the catalyst amount of the catalyst carrier 3b can be reduced, and the single unit cost can be kept low.
Further, when the vehicle normally travels after the end of the separation of the adsorbing member 2b, there is no need to allow exhaust to pass through the adsorbing member 2b having a relatively large ventilation resistance, and the exhaust resistance can be reduced and the output can be improved.

Next, FIG. 7 shows the results obtained through experiments and the like in relation to the time (Time) and the hydrocarbon emission amount (HC Emission) in the cases (1) to (4) described above.
As shown in FIG. 7, the inventive product of Example 1 can suppress the amount of hydrocarbons discharged before the catalyst carrier 3b is activated in (3) described above.

Next, the effect will be described.
As described above, in the first embodiment, the controller 14 opens the valve V1 of the main pipe 5 and closes the valve V2 of the bypass pipe 6 after the adsorption member 2b is detached. Thus, since the entire amount of exhaust gas from the engine a1 flows into the main pipe 5, the exhaust does not pass through the adsorption member 2b via the bypass pipe 6 after the adsorption member 2b has been detached, and the adsorption member 2b Durability can be improved.

Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, in the first embodiment, the adsorption unit 2 and the catalyst unit 3 are configured separately and connected to each other. However, they can be accommodated in a common cylindrical main body 4.

  In the first embodiment, the temperatures of the adsorbing member 2b and the catalyst carrier 3b are directly detected by the temperature sensors 16 and 17, but may be detected using other various sensors or estimated based on information from the ECU 15. good.

1 is an overall view showing an exhaust system of Example 1. FIG. 1 is a side view showing a catalytic converter with an adsorbing member of Example 1. FIG. It is a figure explaining the effect | action of Example 1. FIG. It is a figure explaining the effect | action of Example 1. FIG. It is a figure explaining the effect | action of Example 1. FIG. It is a figure explaining the effect | action of Example 1. FIG. It is a figure which shows the experimental result explaining the effect of Example 1. FIG.

Explanation of symbols

a1 engine a2 catalytic converter a3 center muffler a4 rear muffler b1, b2, b3, b4 connecting pipe R1, R2 chamber V1, V2 valve 1 catalytic converter with adsorbing member 2 adsorbing part 2a outer cylinder 2b adsorbing member 3 catalyst part 3a outer cylinder 3b catalyst carrier 4 Body 5 Main pipe 6 Bypass pipe 7 Shell 8 End plate 9 Shell 10 Diffuser 11 Flange 12 Partition member 12a Communication hole 13 Flange 14 Controller 15 Engine control unit (ECU)
16, 17 Temperature sensor

Claims (1)

A main body containing an adsorbing member capable of adsorbing and desorbing hydrocarbons in the exhaust, and a catalyst carrier arranged in communication with the downstream side of the adsorbing portion and capable of purifying exhaust;
A main pipe that guides exhaust from the engine to the catalyst carrier;
A bypass pipe branched from the upstream side of the main pipe to guide exhaust from the engine to the adsorbing member;
A valve provided on each downstream side of the branch position in the main pipe and the bypass pipe;
A control unit capable of controlling the opening and closing operation of both valves;
The control unit closes the main pipe valve and opens the bypass pipe valve until the adsorbing member reaches the separation temperature in accordance with the exhaust gas temperature rise from the start of the engine,
From the desorption temperature of the adsorption member until the catalyst carrier reaches the activation temperature, the valve of the main pipe is opened while the valve of the bypass pipe is closed,
From the time when the catalyst carrier reaches the activation temperature until the adsorbing member finishes detachment, both valves are opened,
The catalytic converter with an adsorbing member is characterized in that after the adsorbing member finishes detachment, the valve of the main pipe is opened while the valve of the bypass pipe is closed.

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