JP7211860B2 - Double layer catalytic converter - Google Patents

Description

The present invention relates to a two-layer catalytic converter provided in the exhaust path of an automobile.

For example, Patent Document 1 discloses an exhaust purification device (catalytic converter) of this type. The one disclosed in this patent document 1 is provided with an inner cylinder and an outer cylinder provided on the outer periphery of the inner cylinder, and the inner cylinder and the outer cylinder are welded circumferentially at one end and the other end, respectively. A gap is formed between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder between one end and the other end, and this gap constitutes an air layer. There is an exhaust purifier (catalyst carrier) housed in the cylindrical portion.

JP 2016-113969 A

However, since the conventional exhaust purification device has a two-layer structure (double-tube structure) of an outer cylinder and an inner cylinder, when a sensor mounting hole is provided that penetrates the outer cylinder and the inner cylinder, the sensor mounting hole It was difficult to secure the gas sealing performance of the part.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-described problems. It is an object of the present invention to provide a two-layer catalytic converter capable of

The present invention provides a two-layered catalytic converter having an outer cylinder and an inner cylinder each provided with a sensor mounting hole , and a flange , wherein the sensor mounting hole is arranged upstream of the exhaust gas from the outer cylinder. A sensor is held in a sensor mounting hole of the outer cylinder, and a clearance through which exhaust gas can pass is formed between the sensor mounting hole of the inner cylinder and the sensor. The inner cylinder is sealingly fixed to the inner surface of the outer cylinder with a seal mat, the inner cylinder is inserted into the exhaust gas inlet of the flange, and the end of the outer cylinder is fixed to the flange. The seal mat is arranged on the downstream side of the exhaust gas from the position of the sensor mounting hole, and is arranged on the upstream side of the exhaust gas from the catalyst carrier provided in the inner cylinder. A space between the outer cylinders is sealed .

According to the present invention, the seal mat interposed between the outer cylinder and the inner cylinder is arranged on the downstream side of the exhaust gas from the position of the sensor mounting hole penetrating the outer cylinder and the inner cylinder. By arranging the catalyst carrier on the upstream side of the exhaust gas, the gas sealing performance of the sensor mounting hole portion can be easily secured and improved.

1 is a partial cross-sectional view showing a two-layer catalytic converter according to a first embodiment of the present invention; FIG. 3 is an enlarged cross-sectional view of a main part of the catalytic converter; FIG. FIG. 4 is an enlarged cross-sectional view showing another example of the main part of the catalytic converter; FIG. 4 is an enlarged cross-sectional view showing another example of the main part of the catalytic converter; FIG. 6 is an enlarged cross-sectional view showing still another example of the main part of the catalytic converter; FIG. 5 is a partial cross-sectional view showing a two-layer catalytic converter according to a second embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial cross-sectional view showing a two-layer structure catalytic converter according to a first embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part of the catalytic converter.

As shown in FIG. 1, the two-layered catalytic converter 10 includes a metal inlet-side flange 11 positioned on the inlet side of the exhaust gas G and a metal outlet-side flange (not shown) positioned on the outlet side of the exhaust gas G. The inlet-side flange 11 is disposed, for example, in an exhaust passage on the exhaust manifold side of the engine.

As shown in FIGS. 1 and 2, the upstream end 21 of the outer cylinder 20 is fixed to the inlet flange 11 by welding E, and the downstream end (not shown) is welded to the outlet flange (not shown). It is stuck. The inner cylinder 30 has an upstream end 31 inserted into the exhaust gas inlet 11a of the inlet flange 11 so as to be slidable, and a downstream end (not shown) of the outlet flange (not shown). It is inserted and slidably mounted in the exhaust gas outlet. As a result, a double tube structure is formed in which an air layer (gap) S is formed between the outer tube 20 and the inner tube 30 .

The diffuser portions 22, 32 on the upstream end portion 21 side of the outer cylinder 20 and on the upstream end portion 31 side of the inner cylinder 30 are formed in a small-diameter cylindrical shape with an L-shaped side surface. It is connected to large-diameter cylindrical container portions 24 and 34 via 33 .

Further, in the diffuser portions 22, 32 of the outer cylinder 20 and the inner cylinder 30, sensor mounting holes 25, 35 for mounting a sensor 40 for detecting the concentration, temperature, etc. of the exhaust gas G are formed in the outer cylinder 20 and the inner cylinder 30. is provided to pass through the

Further, a seal mat (a sealing mat ( A heat insulating member) 41 is interposed to seal the diffuser portions 22, 32 of the outer cylinder 20 and the inner cylinder 30 so that the exhaust gas G does not flow from between the container portions 24, 34 side. The seal mat 41 as a heat insulating member has a surface pressure (elastic force) capable of holding the inner cylinder 30 and has a low thermal conductivity. Further, the seal mat 41 is arranged downstream of the exhaust gas G from the positions of the sensor mounting holes 25 and 35, and is upstream of the exhaust gas G from a later-described catalyst carrier 38 provided in the inner cylinder 30. are placed in As a result, the inner cylinder 30 is fixed to the inner surface of the outer cylinder 20 by means of the seal mat 41 so as to be sealed to the inner surface of the outer cylinder 20. As shown in FIG. Leakage to the air layer (gap) S on the downstream side of the seal mat 41 between the diffuser portions 22 and 32 of the outer cylinder 20 and the inner cylinder 30 is prevented.

Further, as shown in FIGS. 1 and 2, between the sensor mounting hole 25 of the diffuser portion 22 of the outer cylinder 20 and the tapered portion 23, there is a recessed annular groove that engages a seal mat 41 to limit its position. is provided so as to protrude outward. Further, a catalyst carrier 38 for purifying the exhaust gas G is accommodated in the container portion 34 of the inner cylinder 30 via a holding mat (holding member) 39 .

The sensor mounting hole 25 of the outer cylinder 20 has a tubular shape and holds the sensor 40 . Furthermore, the downstream end portions (not shown) of the outer cylinder 20 and the inner cylinder 30 are formed into a small-diameter cylindrical shape from the diffuser portions 22 and 32 via a tapered portion (not shown) having an inverted conical cylinder shape to an outlet side flange (not shown). Concatenated. Further, the air layer S on the downstream side of the seal mat 41 between the diffuser portions 22 and 32 of the outer cylinder 20 and the inner cylinder 30 communicates with the container portions 24 and 34 of the outer cylinder 20 and the inner cylinder 30. .

As described above, according to the two-layer structure catalytic converter 10 of the first embodiment, the seal mat 41 interposed between the diffuser portion 22 of the outer cylinder 20 and the diffuser portion 32 of the inner cylinder 30 is separated from the outer cylinder 20 and the inner cylinder. 30 on the downstream side of the exhaust gas G from the positions of the sensor mounting holes 25, 35, and on the upstream side of the exhaust gas G from the catalyst carrier 38 provided in the container portion 34 of the inner cylinder 30. As a result, as shown in FIG. 2, the exhaust gas G flowing from the sensor mounting hole 35 of the inner cylinder 30 is directed downstream of the seal mat 41 between the diffuser portions 22, 32 of the outer cylinder 20 and the inner cylinder 30. Leakage to the air layer S side can be prevented. As a result, it is possible to secure and improve gas sealing performance (sealing performance against leakage of unpurified gas) with a simple structure, and the number of gas sealing positions can be reduced, improving the degree of freedom in design. can be made Furthermore, since it is not necessary to consider the gas sealing properties of the sensor mounting holes 25 and 35 of the outer cylinder 20 and the inner cylinder 30, the number of parts can be reduced accordingly.

In addition, the diffuser portion 22 of the outer cylinder 20 is provided with a recessed ring-shaped restriction portion 26 that retains the seal mat 41 and restricts its position, thereby preventing the seal mat 41 from shifting due to vibration, exhaust pressure, and the like. can do. Furthermore, since the shape of the restricting portion 26 is a concave annular shape into which the seal mat 41 is fitted, the shape of the seal mat 41 can be simplified, and the production yield can be improved.

According to the first embodiment, as shown in FIG. 2, the restricting portion 26 having a recessed annular shape, which engages the seal mat 41 and restricts its position, protrudes outward from the diffuser portion 22 of the outer cylinder 20. As shown in FIG. However, as shown in FIG. 3, a restricting portion 27 having an L-shaped cross section is provided in the diffuser portion 22 of the outer cylinder 20 so as to protrude outward, and the seal mat 41 is locked to the position. Also, as shown in FIG. 4, the diffuser portion 32 of the inner cylinder 30 has a recessed ring-shaped restricting portion 36 that engages the seal mat 41 and restricts its position so as to protrude inward. Alternatively, as shown in FIG. 5, a restricting portion 37 having an L-shaped cross section is provided in the diffuser portion 32 of the inner cylinder 30 so as to protrude inward, and the seal mat 41 is locked and its position is determined. You can limit it.

Furthermore, in the first embodiment, the restricting portion for locking the seal mat to either one of the outer cylinder and the inner cylinder to limit its position is provided. A restricting portion may be provided for stopping and restricting the position. Further, the concave or L-shaped shape may not be a right angle, and may be provided so as to protrude inward without being limited to the outside, or may be provided so as to protrude outward without being limited to the inside.

FIG. 6 is a partial cross-sectional view showing a two-layer catalytic converter according to a second embodiment of the present invention.

In the two-layer catalytic converter 10' of the second embodiment, a TWC (three-way catalyst) 38 as a first catalyst carrier is placed in a container portion 34 of an inner cylinder 30 on the downstream side of a TWC (three-way catalyst) 38 as a second catalyst carrier. This embodiment differs from the first embodiment in that a gasoline particulate filter (GPF) or a diesel particulate filter (DPE) 48 is accommodated via a holding mat (holding member) 49 .

Between the first catalyst carrier 38 and the second catalyst carrier 48 of the container portion 24 of the outer cylinder 20 and the container portion 34 of the inner cylinder 30, a second catalyst for detecting the pressure, temperature, etc. of the exhaust gas G is provided. Second sensor mounting holes 25 ′ and 35 ′ for mounting the sensor 42 are provided so as to pass through the outer cylinder 20 and the inner cylinder 30 . Further, downstream of the sensor mounting hole 25' of the container portion 24 of the outer cylinder 20, a recessed ring-shaped restricting portion 28 for locking the seal mat 43 and restricting its position is provided so as to protrude outward. ing. Since the rest of the configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the two-layer structure catalytic converter 10' of the second embodiment, the exhaust gas G flowing in through the second sensor mounting hole 35' of the inner cylinder 30 is transferred to the container portions 24, 34 of the outer cylinder 20 and the inner cylinder 30. It is possible to prevent leakage to the air layer S side on the downstream side of the seal mat 43 between them. As a result, it is possible to secure and improve gas sealing performance (sealing performance against leakage of unpurified gas) with a simple structure. ' and 35' need not be taken into account, the number of parts can be reduced accordingly.

The shape of the recessed ring-shaped restricting portion 28 for retaining the seal mat 43 and restricting its position may be such that it protrudes inward rather than outward as in the first embodiment, or has an L-shaped cross section. Of course, it may be provided on the side of the inner cylinder.

10,10' two-layer catalytic converter
11 inlet side flange (flange)
11a Exhaust gas inlet
20 Outer cylinder
21 upstream end (end)
22 diffuser section 24 container section 25 sensor mounting hole 25' second sensor mounting hole 26, 27, 28 regulation section 30 inner cylinder 32 diffuser section 34 container section 35 sensor mounting hole 35' second sensor mounting hole 36, 37 Regulator 38 First catalyst carrier (catalyst carrier)
48 second catalyst carrier 40 sensor 42 second sensor 41, 43 seal mat (heat insulating member)
G Exhaust gas

Claims (4)

A catalytic converter having a two-layer structure having an outer cylinder and an inner cylinder each provided with a sensor mounting hole and a flange ,
The sensor mounting hole is provided on the upstream side of the exhaust gas so as to penetrate the outer cylinder and the inner cylinder,
A sensor is held in the sensor mounting hole of the outer cylinder, and a clearance through which exhaust gas can pass is formed between the sensor mounting hole of the inner cylinder and the sensor,
The inner cylinder is sealingly fixed to the inner surface of the outer cylinder with a seal mat,
The inner cylinder is inserted into the exhaust gas inlet of the flange,
The end of the outer cylinder is fixed to the flange,
The seal mat is arranged on the downstream side of the exhaust gas from the position of the sensor mounting hole, and is arranged on the upstream side of the exhaust gas from the catalyst carrier provided in the inner cylinder. A two-layered catalytic converter characterized in that the space between the cylinders is sealed . The two-layer catalytic converter according to claim 1,
A catalytic converter having a two-layer structure, wherein the seal mat is provided in a diffuser portion between the inner cylinder and the outer cylinder. The two-layer catalytic converter according to claim 1 or 2,
A catalytic converter of a two-layer structure, wherein at least one of the inner cylinder and the outer cylinder is provided with a regulating portion that locks the seal mat to restrict its position. The two-layer catalytic converter according to any one of claims 1 to 3,
A first catalyst carrier and a second catalyst carrier are respectively arranged inside the inner cylinder,
A second sensor mounting hole is provided in each of the inner cylinder and the outer cylinder between the first catalyst carrier and the second catalyst carrier,
At least one of the inner cylinder and the outer cylinder is provided with a regulating portion that locks the seal mat and restricts its position on the downstream side of the second sensor mounting hole. Layered catalytic converter.

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