JPH11294156A - Exhaust device for vehicular engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate manufacture, improve strength, and suppress possibility of exhaust leakage in an exhaust device of a vehicular engine for instance, particularly the exhaust device of a multicylinder engine. SOLUTION: An inner space of an exhaust pipe 1 connected to a portion on a downstream side of an exhaust manifold of an engine is divided into a plurality of parts by a partition plate 2. In such an exhaust device for a vehicular engine, an end 21 of the partition plate 2 abutted against an inner surface of the exhaust pipe has a bladder-like form. The bladder-like end 21 of the partition plate 2 is integrally fixed to the inner surface of the exhaust pipe by welding W, etc., as required. A bent portion 22 is formed on substantially a center portion of the partition plate 2 in a widthwise direction, as required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a vehicle engine such as an automobile, and more particularly to an exhaust system for a multi-cylinder engine.

[0002]

2. Description of the Related Art An exhaust system as described above generally connects an exhaust pipe called a front pipe to an exhaust manifold of an engine, and a downstream side of the exhaust pipe is provided with a catalytic converter for purifying exhaust gas and a silencer. Are connected. In this case, in the case of a multi-cylinder engine, if the exhaust manifold directly joins one exhaust pipe, the engine is back-pressured and the output decreases, so that a plurality of exhaust pipes may be provided corresponding to the number of cylinders. ,
Alternatively, a method is adopted in which exhaust gases, which are less likely to interfere with each other, of the exhaust gases from the cylinders are joined in the manifold, guided to a plurality of exhaust pipes, and then joined to one exhaust pipe.

[0003] For example, in a four-cylinder engine, of the four exhaust cylinders, two cylinders, each of which is less likely to interfere with each other, are joined together in the manifold and led to two exhaust pipes, and the two exhaust pipes are exhausted. The pipes are merged into one exhaust pipe so as to lead to a catalytic converter and a muffler.

However, the arrangement of a plurality of exhaust pipes as described above requires a large installation space,
2. Description of the Related Art It is often difficult to install an exhaust system for a vehicle engine such as an automobile in a limited space at the bottom of a vehicle body. In addition, since the surface area is large, there is a problem that the exhaust gas temperature is lowered before reaching the catalytic converter installed downstream and the exhaust purification performance is reduced.

[0005] Therefore, for example, the inside of the exhaust pipe from the exhaust manifold to the catalytic converter is partitioned by a partition plate, or the exhaust pipe itself is formed into an S-shaped cross section, thereby reducing the number of parts.
It has been proposed to form a plurality of exhaust passages in one exhaust pipe (for example, see Japanese Utility Model Application Laid-Open No. 63-196425 and Japanese Patent Application Laid-Open No. 9-264128).

[0006]

However, in the former, the inside of the exhaust pipe is partitioned by a partition plate, as shown in FIGS. 6 and 7, for example, as shown in FIG. 6 and FIG.
In general, a is bent in opposite directions and fixed to the inner surface of the exhaust pipe 1 by welding or the like. In this case, since the partition plate 2 is asymmetrical as shown in FIG. 7, the stability is poor. At the time of welding, it is necessary to insert a jig or the like into the exhaust pipe in an unstable state and perform welding. There are problems such as poor workability. At the time of welding, welding spatter adheres to the jig and impairs welding accuracy, and the jig needs to be cleaned or replaced frequently.Furthermore, welding spatter adheres to the inside of the pipe, causing corrosion from that location. There was a problem.

Further, when performing the above welding work, in order to improve welding strength or to prevent corrosion from the welded portion and its surroundings, the welding is performed while flowing an inert gas called a back shield gas. However, the exhaust pipe of a vehicle engine or the like requires a large amount of gas since the pipe has a relatively large volume, and is practically not applicable.

The present invention has been proposed in view of the above-mentioned conventional problems, and provides an exhaust device which is easy to manufacture, has high strength, has excellent corrosion resistance, and has a low possibility of causing exhaust leakage. With the goal.

[0009]

To achieve the above object, an exhaust system for a vehicle engine according to the present invention has the following arrangement. That is, in an exhaust device for a vehicle engine in which a plurality of exhaust passages are formed by partitioning the inside of an exhaust pipe connected to the downstream side of an exhaust manifold of the engine with a partition plate, the exhaust pipe contacts the inner surface of the exhaust pipe of the partition plate. The end portion is formed in a bag shape.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an exhaust system for a vehicle engine according to the present invention will be specifically described based on an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view showing one embodiment of the exhaust device according to the present invention, and FIGS. 2A and 2B are sectional views taken along lines AA and BB in FIG.

In the illustrated exhaust device, a partition plate 2 is disposed in an exhaust pipe 1, and both ends 21 in the width direction of the partition plate 2 which are in contact with the inner surface of the exhaust pipe are formed in a bag shape. 2
A bent portion 22 is formed substantially at the center in the width direction.
The bag-shaped end 21 is elastically and air-tightly adhered to the inner surface of the exhaust pipe 1 by the bent portion 22, and a weld W
, The partition plate 2 and the exhaust pipe 1 are integrally fixed. The edge 21s on the upstream side (upper left in FIG. 1) of the bag-like end 21 is closed by being squashed flat as shown in FIG. To prevent inflow.

In FIG. 1, reference numerals 11 and 12 denote the exhaust pipe 1
Connection flanges provided at the upstream and downstream ends of the engine, the exhaust pipe 1 is connected to an exhaust manifold of an engine (not shown) by an upstream flange 11, and a catalytic converter is connected to a downstream flange 12. Are connected, and a muffler and the like are connected downstream thereof, but they are omitted in the figure.

Although the materials and dimensions of the members constituting the exhaust device are appropriate, the materials of the exhaust pipe 1 and the partition plate 2 in this embodiment are stainless steel plates (S
US430M). The exhaust pipe 1 has a thickness of 0.8 mm and an outer diameter of 65 mm. On the other hand, it is preferable that the plate thickness of the partition plate 2 is 1.2 mm or more, and in the present embodiment, the plate thickness is 1.2 mm.

The sectional shape and dimensions of the bag-like end 21 are also appropriate, but the sectional shape of the bag-like end 21 in the illustrated example is shown in FIG.
2 (b), the bag-shaped end 21 has a maximum width in the left-right direction of about 10 mm in FIG. The contact portion of the bag-shaped end portion 21 with the inner surface of the exhaust pipe is formed on an arc surface having substantially the same curvature as the inner surface of the exhaust pipe, and the length (contact width) of the contact portion in the circumferential direction of the exhaust pipe is about 7 mm. It is.

The method of manufacturing the exhaust pipe 1 and the partition plate 2 is arbitrary. For example, the exhaust pipe 1 and the partition plate 2 are individually manufactured in advance by press forming, roll forming, or other manufacturing methods. Combine them. Alternatively, the exhaust pipe 1 and the partition plate 2 can be integrally combined by being continuously formed while being simultaneously formed by roll forming or the like.

FIG. 3 shows an example in which the exhaust pipe 1 and the partition plate 2 are separately manufactured and combined, and FIG.
The exhaust pipe 1 previously formed into a circular tubular shape and cut into a predetermined length as described above is deformed into an elliptical shape by being pressed from both right and left sides by a pressing member or the like not shown in the drawing, and the exhaust pipe 1 is placed in the exhaust pipe 1. The partition plate 2 is inserted from one end side. If the above-mentioned pressing member is removed in that state, the exhaust pipe 1 returns to its original circular shape as shown in FIG. 3B by its elastic restoring force, and the partition plate 2 stands in the diameter direction of the exhaust pipe 1. Is held in position.

In particular, both ends 2 in the width direction of the partition plate 2 of the present invention
1 and 21 are formed in a bag shape, and the contact portion between the bag-shaped end portion 21 and the inner surface of the exhaust pipe has a predetermined width as described above, and the contact portion is located at the center of the partition plate 2 in the illustrated example. Since it is substantially symmetrical with respect to the plate surface of the portion, it can be stably positioned and held at the center of the exhaust pipe 1. In this case, the width of the partition plate 2, that is, the length in the vertical direction in FIG. 3B is formed to be slightly larger than the inner diameter (diameter) of the exhaust pipe 1, or at least in the partition plate width direction of the exhaust pipe 1. Is formed to be smaller than the width of the partition plate 2, when the partition plate 2 is mounted in the exhaust pipe 1 as shown in FIG. Can be tightly fixed.

Next, the bag-like end 21 of the partition plate 2 and the inner surface of the exhaust pipe are integrally fixed by welding W or the like. As a welding method, for example, laser welding, high-frequency welding, or the like is applied. can do. At that time, the partition plate 2
Is stably positioned and held in the exhaust pipe 1, so that a strong jig is not necessarily required, and a simple jig can be used to easily and reliably fix the jig. In some cases, the jig can be omitted.

FIG. 4 shows an example of a manufacturing method in a case where the exhaust pipe 1 and the partition plate 2 are continuously combined while being formed simultaneously and integrated. Material plate 2 of partition plate 2 wound in a roll
While sequentially feeding 0, the partition plate 2 having a predetermined shape is sequentially formed by a large number of forming rollers 3. At the same time, the flat material plate 10 for forming the exhaust pipe 1 is sequentially curved into a circular shape by a number of forming rollers 4, and the material plate 10 is rounded into a cylindrical shape so as to wrap the partition plate 2 inward. Welding W1 may be performed by welding the ends while abutting the ends, and bringing the bag-shaped ends 21 of the partition plate 2 into close contact with the inner surface of the exhaust pipe. Also in this example, since the partition plate is substantially symmetric, it can be positioned at the center of the exhaust pipe without falling down.

In the above embodiment, as shown in FIG.
Was welded at the lateral position of
May be integrally welded to the partition plate 2 at the outer surface position.

After the exhaust pipe 1 and the partition plate 2 are integrated as described above, they are appropriately bent in accordance with the shape of the arrangement on the vehicle bottom or the like. When such a bent portion 22 is formed, functions such as stress relaxation at the time of performing the bending process and stress relaxation against shrinkage of the partition plate due to the exhaust temperature when the vehicle is mounted on the vehicle are exhibited, and the welded portion between the partition plate and the pipe is formed. Peeling or separation can be prevented beforehand.

If there is a possibility that the bending edge of the bag-shaped end 21 may be opened due to the sharp bending of the bending process, for example, as shown in FIG. The partition plate 2 is extended to the plate surface at the center in the width direction of the partition plate 2 and is attached to the plate surface.
You may make it.

In the above-mentioned conventional structure shown in FIGS. 6 and 7, since the partition plate 2 is asymmetrical as described above, the stability is poor.
At the time of welding, a jig having almost no extra space had to be used, and there were problems such as poor workability. However, in the above embodiment according to the present invention, since the partition plate 2 is substantially symmetric, Is good, and the jig has room. In addition, the bending portion (heming portion) 2a at both ends of the conventional partition plate 2 is apt to cause so-called waving, and a wavy portion on the inner side of the exhaust pipe has a gap between the exhaust pipe and the weld, resulting in poor welding. Although there is a problem that it is difficult to obtain stable welding, in the present invention, both ends 21 of the partition plate 2 are formed in a bag shape and the ends 2 are formed.
The first edge 21a is brought into contact with the partition plate body,
Since the end 21 is brought into contact with the inner surface of the exhaust pipe without causing waving or the like, welding and fixing can be performed satisfactorily and stably. In addition, even when the exhaust pipe is used, the corrosive exhaust gas does not directly come into contact with the welded portion or its vicinity, so that the corrosion resistance can be improved.

Further, the above welding operation is generally performed from the outside of the exhaust pipe. Conventionally, welding spatter or the like scatters on the exhaust pipe and adheres to the inner surface of the exhaust pipe to cause corrosion, or welding spatter is generated by a welding jig. However, the welding spatter and the like are collected in the bag-shaped end portion 21 in the present invention. Since the particles do not scatter in the exhaust pipe, the above-mentioned problems can be solved satisfactorily.

Further, by forming both ends 21 of the partition plate 2 to be welded to the exhaust pipe 1 in a bag shape, the volume of the space in contact with the welding area in the exhaust pipe 1 can be reduced, so that the bag-shaped end portion is formed. It is possible to perform welding while flowing a back shield gas to the gas. Thereby, the welding strength can be increased, and the occurrence of corrosion can be reduced without deterioration of the welded portion and its vicinity by active gas or the like during welding.

In the above-described embodiment, the exhaust pipe 1 is made single, but, for example, in order to prevent the exhaust gas temperature from dropping from the engine to the catalytic converter, a heat insulating material is provided around the outer circumference of the exhaust pipe 1. May be coated. In this case, the space between the exhaust pipe 1 and the outer pipe may be hollow to form an air heat insulating layer, or the space between the exhaust pipe and the outer pipe may be filled with a heat insulating material such as glass wool.

[0027]

As described above, the present invention provides a vehicle engine in which a plurality of exhaust passages are formed by partitioning an exhaust pipe 1 connected to a downstream side of an exhaust manifold of an engine by a partition plate 2. In the exhaust device described above, since the end 21 of the partition plate 2 that contacts the inner surface of the exhaust pipe is formed in a bag shape, both ends of the partition plate 2 are elastically and stably held in close contact with the inner surface of the exhaust pipe. Can be. Therefore, when welding both ends of the partition plate and the inner surface of the exhaust pipe, the partition plate 2 can be fixed without necessarily using a strong jig or the like. Since the exhaust gas does not come into direct contact, corrosion is small and durability can be greatly improved. Further, at the time of welding, welding spatter does not adhere to the jig, so that the jig does not need to be frequently cleaned or replaced, and does not adhere to the inside of the pipe. In addition, it is possible to perform welding while flowing a back shield gas to the bag-shaped end portion 21, thereby increasing the welding strength, and at the time of welding, the welded portion and its vicinity are deteriorated by active gas or the like, which causes corrosion. And the like.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal side view showing an embodiment of an exhaust device for a vehicle engine according to the present invention.

FIGS. 2A and 2B are enlarged cross-sectional views taken along lines AA and BB in FIG.

FIGS. 3A and 3B are explanatory diagrams illustrating an example of a method of manufacturing the exhaust device.

FIG. 4A is an explanatory view showing another example of a method of manufacturing the exhaust device. (B), (c), and (d) show B- in (a).
B, CC, DD sectional drawing.

FIG. 5 is a sectional view showing another embodiment of the exhaust device for a vehicle engine according to the present invention.

FIG. 6 is a partially longitudinal side view showing an example of a conventional exhaust device.

FIG. 7 is an enlarged sectional view taken along line EE in FIG. 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 exhaust pipe 2 partition plate 11, 12 connection flange 21 bag-like end 22 bent part

Claims (3)

[Claims] 1. An exhaust system for a vehicle engine in which an exhaust pipe connected to a downstream side of an exhaust manifold of the engine is partitioned by a partition plate to form a plurality of exhaust passages. An exhaust device for a vehicle engine, wherein an end portion of the exhaust device is formed in a bag shape. 2. The exhaust system for a vehicle engine according to claim 1, wherein a contact portion between the bag-like end of the partition plate and the inner surface of the exhaust pipe is integrally fixed by welding. 3. The exhaust device for a vehicle engine according to claim 1, wherein a bent portion is formed at a substantially central portion in a width direction of the partition plate.