WO2012069922A1

WO2012069922A1 - Exhaust system

Info

Publication number: WO2012069922A1
Application number: PCT/IB2011/002962
Authority: WO
Inventors: Yasuhiko Koda; Takaharu Nagatoshi; Keisuke Yasunaka
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2010-11-24
Filing date: 2011-11-24
Publication date: 2012-05-31
Also published as: CN102869866B; CN102869866A; JP5158182B2; BR112012031376A2; JP2012112279A

Abstract

In an exhaust system, a dropdown-preventing portion (15) that hangs an exhaust pipe (2, 4) on an auxiliary exhaust device (3) when a joint (8b) of the auxiliary exhaust device (3) and the exhaust pipe (2, 4) separates, is provided on at least one of the auxiliary exhaust device (3) and the exhaust pipe (2, 4) to which the auxiliary exhaust device (3) is joined.

Description

EXHAUST SYSTEM

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The invention relates to an exhaust system that includes an exhaust pipe that is attached to an engine and an auxiliary exhaust device that is arranged midway in this pipe and is suspended from a vehicle body, and in which at least one of an upstream side and a downstream side in the direction in which exhaust gas flows of the auxiliary exhaust device is joined to the exhaust pipe by welding.

2. Description of Related Art

[0002] Normally, an auxiliary exhaust device such as a muffler or a catalytic converter is arranged midway in an exhaust pipe of an engine. This kind of auxiliary exhaust device typically has an outer shape that is larger than the exhaust pipe, but the upstream side and the downstream side in the exhaust gas flow direction of the auxiliary exhaust device are small-diameter cylindrical tubes, and these small-diameter tubes are joined to the exhaust pipe by welding.

[0003] Japanese Patent Application Publication No. 2002-138826 (JP-A-2002-138826), for example, describes an auxiliary exhaust device supported hanging down from a vehicle body. Also, a muffler that is referred to as a rear muffler is arranged at the end in the exhaust gas flow direction of an exhaust pipe positioned downstream of the auxiliary exhaust device (referred to as the rear exhaust pipe). This muffler is supported hanging down from the vehicle body.

[0004] In this kind of exhaust system, if the joint of the auxiliary exhaust device and the rear exhaust pipe were ever to separate, the joining end of the rear exhaust pipe hang down, and if it hangs down excessively, it may drag on the road surface.

[0005] With respect to this, with the technology described in Japanese Patent Application Publication No. 2001-342830 (JP-A-2001-342830), for example, the small-diameter tubes of the auxiliary exhaust device are joined to the exhaust pipe using screws, which makes it more difficult for the joint to separate.

[0006] JP-A-2001-342830 describes an invention for making it more difficult for the joint of the auxiliary exhaust device and the exhaust pipe to separate, but it is not designed to deal with the joint separating, however unlikely it may be. Also, JP-A-2001-342830 requires that a male thread groove and a female thread groove be formed in the small-diameter tubes of the auxiliary exhaust device and in the exhaust pipe. As a result, the cost may rise due to the trouble involved with machining and attaching the screw joining portions and the like.

SUMMARY OF THE INVENTION

[0007] The invention thus provides an exhaust system that includes an exhaust pipe that is attached to an engine, and an auxiliary exhaust device that is arranged midway in the exhaust pipe and is fixed to a vehicle body, and in which at least one of an upstream side and a downstream side in an exhaust gas flow direction of the auxiliary exhaust device is joined to the exhaust pipe by welding, that is able to prevent, through a relatively inexpensive measure, the auxiliary exhaust device or the exhaust pipe from hanging down and dragging on the road surface in the unlikely event that a joint of the auxiliary exhaust device and the exhaust pipe separates.

[0008] A first aspect of the invention relates to an exhaust system that includes an exhaust pipe that is attached to an engine, and an auxiliary exhaust device that is arranged midway in the exhaust pipe and is fixed to a vehicle body, in which at least one of an upstream side and a downstream side in an exhaust gas flow direction of the auxiliary exhaust device is joined to the exhaust pipe by welding, and a dropdown-preventing portion that hangs the exhaust pipe on the auxiliary exhaust device when a joint of the auxiliary exhaust device and the exhaust pipe separates, is provided on at least one of the auxiliary exhaust device and the exhaust pipe to which the auxiliary exhaust device is joined. [0009] When this kind of dropdown-preventing portion is provided, in the unlikely event that the joint of the auxiliary exhaust device and the exhaust pipe separates, even though the joining end of the exhaust pipe would hang down, this joining end of the exhaust pipe would catch on the dropdown-preventing portion. Therefore, even though the joining end of the exhaust pipe would hang down slightly, it would be supported by the auxiliary exhaust device via the dropdown-preventing portion and would thus not hang down very far. As a result, even if the joint were to separate in this fashion, the joining end of the exhaust pipe would not drag on the road surface, so the vehicle could be driven without any problem to a repair shop, for example.

[0010] Moreover, the dropdown-preventing portion is simply arranged on the auxiliary exhaust device or the exhaust pipe, so an increase in equipment cost can be suppressed, which in turn enables the exhaust system to be provided at low cost.

[0011] In the exhaust system according to this aspect, the auxiliary exhaust device may be fixed suspended from the vehicle body.

[0012] Also, in the exhaust system described above, the downstream side in the exhaust gas flow direction of the auxiliary exhaust device may be joined to a rear exhaust pipe that is a downstream side portion of the exhaust pipe, and the dropdown-preventing portion may be arranged on a vertically upper side of a joining end of the rear exhaust pipe and be shaped extending toward the auxiliary exhaust device.

[0013] In this case, when the joining end of the rear exhaust pipe hangs down as a result of the joint of the auxiliary exhaust device and the rear exhaust pipe separating, the dropdown-preventing portion that is arranged on the joining end of the rear exhaust pipe becomes hung up in a manner covering the upper half of the downstream joining end of the auxiliary exhaust device. Therefore, even though the joining end of the rear exhaust pipe would hang down slightly, it would not hang down so much that it would drag on the road surface.

[0014] Also, in the exhaust system described above, the auxiliary exhaust device and the rear exhaust pipe may be arranged in a non-contacting manner inside an upward arching concave portion that is arranged in a bottom portion of the vehicle body, a tip end portion on the auxiliary exhaust device side of the dropdown-preventing portion may be formed in a semi-cylindrical shape that opens downward, and a separation dimension between both ends in a circumferential direction of the semi-cylindrically shaped portion may be set larger than a separation dimension between a joining end on the downstream side in the exhaust gas flow direction of the auxiliary exhaust device and an inside surface of the upward arching concave portion.

[0015] When the dimensions are set in this way, even if the rear exhaust pipe were to swing sideways while the joint of the auxiliary exhaust device and the rear exhaust pipe is separated, the dropdown-preventing portion that is arranged at the joining end of this rear exhaust pipe is prevented from slipping down from the separation portion of the downstream joining end of the auxiliary exhaust device and the inside surface of the upward arching concave portion of the vehicle body.

[0016] Also, in the exhaust system described above, the downstream side in the exhaust gas flow direction of the auxiliary exhaust device may be joined to a rear exhaust pipe that is a downstream side portion of the exhaust pipe, and the dropdown-preventing portion may be arranged on a vertically lower side of the auxiliary exhaust device and be shaped extending toward the rear exhaust pipe.

[0017] In this case, when the joining end of the rear exhaust pipe hangs down as a result of the joint of the auxiliary exhaust device and the rear exhaust pipe separating, the joining end of the rear exhaust pipe is caught by (i.e., received by) the dropdown-preventing portion that is arranged on the auxiliary exhaust device. Therefore, even though the joining end of the rear exhaust pipe would hang down slightly, it would not hang down so much that it would drag on the road surface.

[0018] Also, in the exhaust system described above, the auxiliary exhaust device and the rear exhaust pipe may be arranged in a non-contacting manner inside an upward arching concave portion that is arranged in a bottom portion of the vehicle body, a tip end portion on the rear exhaust pipe side of the dropdown-preventing portion may be formed in a semi-cylindrical shape that opens upward, and a separation dimension between one end in a circumferential direction of the semi-cylindrically shaped portion and a portion of an inside surface of the upward arching concave portion that is closest to the one end, and a separation dimension between the other end in the circumferential direction of the semi-cylindrically shaped portion and a portion of the inside surface of the upward arching concave portion that is closest to the other end, may be set smaller than a diameter dimension of a joining end of the rear exhaust pipe.

[0019] When the dimensions are set in this way, even if the rear exhaust pipe were to swing sideways while the joint of the auxiliary exhaust device and the rear exhaust pipe is separated, the joining end of this rear exhaust pipe is prevented from slipping down from the separation portion of the dropdown-preventing portion and the inside surface of the upward arching concave portion of the vehicle body.

[0020] The invention thus provides an exhaust system that includes an exhaust pipe attached to an engine, and an auxiliary exhaust device that is arranged midway in the exhaust pipe and is fixed to a vehicle body, and in which at least one of an upstream side and a downstream side in an exhaust gas flow direction of the auxiliary exhaust device is joined to the exhaust pipe by welding, that is able to prevent, through a relatively inexpensive measure, the auxiliary exhaust device or the exhaust pipe from hanging down and dragging on the road surface in the unlikely event that a joint of the auxiliary exhaust device and the exhaust pipe separates. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a side view showing the general structure of an exhaust system according to one example embodiment of the invention;

FIG. 2 is an enlarged side view of the main portions in FIG. 1;

FIG. 3 is a perspective view showing an auxiliary exhaust device and a rear exhaust pipe in FIG. 1 separated;

FIG. 4 is an arrow view of a cross-section taken along line IV - IV in FIG 2; FIG. 5 is a view of the auxiliary exhaust device and the rear exhaust pipe in FIG. 2 when they are separated;

FIG. 6 is a view showing sideways movement of the rear exhaust pipe when the auxiliary exhaust device and the rear exhaust pipe in FIG. 4 are separated;

FIG. 7 is a view corresponding to FIG. 4, of an exhaust system according to another example embodiment of the invention;

FIG. 8 is a perspective view of the auxiliary exhaust device and the rear exhaust pipe separated, in an exhaust system according to yet another example embodiment of the invention;

FIG. 9 is a side view corresponding to FIG. 2, of an exhaust system according to still another example embodiment of the invention;

FIG. 10 is an arrow view taken along line X - X in FIG. 9;

FIG. 11 is a view showing an auxiliary exhaust device and a rear exhaust pipe in FIG. 9 separated; and

FIG. 12 is a view showing sideways movement of the rear exhaust pipe when the auxiliary exhaust device and the rear exhaust pipe in FIG. 10 are separated.

DETAILED DESCRIPTION OF EMBODIMENTS

[0022] Hereinafter, example embodiments of the invention will be described in detail with reference to the drawings.

[0023] FIGS. 1 to 6 show a first example embodiment of the invention. FIG. 1 is a view of an engine 1, and an exhaust system that includes a front exhaust pipe 2, an auxiliary exhaust device 3, a rear exhaust pipe 4, and a rear muffler 5.

[0024] In this example embodiment, the front exhaust pipe 2 includes an exhaust manifold, not shown. The auxiliary exhaust device 3 may be a muffler or a catalytic converter or the like. The rear muffler 5 is arranged at the end in the exhaust gas flow direction of the rear exhaust pipe 4.

[0025] Also, the auxiliary exhaust device 3 has an outer shape that is larger than the front exhaust pipe 2 and the rear exhaust pipe 4. In this example embodiment, the auxiliary exhaust device 3 has an elliptic cylindrical shape.

[0026] The upstream and downstream sides in the exhaust gas flow direction of the auxiliary exhaust device 3 are small-diameter tubes 3a and 3b of substantially the same diameter as the front exhaust pipe 2 and the rear exhaust pipe 4. The upstream side small-diameter tube 3a is joined by welding to the front exhaust pipe 2, and the downstream side small-diameter tube 3b is joined by welding to the rear exhaust pipe 4. The front joint is denoted by reference character 8a and the rear joint is denoted by reference character 8b.

[0027] Also, the auxiliary exhaust device 3 is supported hanging down from a vehicle body 10 via a support member 6. Further, the rear muffler 5 is supported hanging down from the vehicle body 10 via a support member 7.

[0028] These support members 6 and 7 are each formed from an elastic body of rubber or the like, for example. A hook bar 12 that is attached to the vehicle body 10 is inserted through an upper through-hole in the front support member 6, and a hook bar 3c that is attached to the auxiliary exhaust device 3 is inserted through a lower through-hole in the front support member 6. A hook bar 13 that is attached to the vehicle body 10 is inserted through an upper through-hole in the rear support member 7, and a hook bar 5a that is attached to the rear muffler 5 is inserted through a lower through-hole in the rear support member 7.

[0029] In this example embodiment, the auxiliary exhaust device 3 and the rear exhaust pipe 4 are arranged in a non-contacting manner inside an upward arching concave portion 11 that is arranged in a bottom portion of the vehicle body 10, as shown in FIG. 4.

[0030] In this kind of exhaust system, if the joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 in particular were ever to separate, the joining end of the rear exhaust pipe may would hang down, and if it hangs down excessively, it may drag on the road surface. The rear exhaust pipe 4 is not supported by the vehicle body 10, while the rear muffler 5 that is arranged on the end side in the exhaust gas flow direction of this rear exhaust pipe 4 is supported by the vehicle body 10. Therefore, if the rear joint 8b separates, the rear exhaust pipe 4 would hang down forward with the support member 7 of the rear muffler 5 as the fulcrum or supporting point. The front exhaust pipe 2 is attached to the engine 1, so even if the joint 8a of the auxiliary exhaust device 3 and the front exhaust pipe 2 were to separate, the front exhaust pipe 2 would not hang down.

[0031] Taking this situation into consideration, the structure described below is employed to prevent the joining end of the rear exhaust pipe 4 from hanging down.

[0032] More specifically, a dropdown-preventing portion 15 is attached nearer the joining end of the rear exhaust pipe 4. This dropdown-preventing portion 15 is shaped so that it will catch (i.e., hang up) on the downstream small-diameter tube 3b of the auxiliary exhaust device 3 in the unlikely event that the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 in particular separates. That is, the dropdown-preventing portion 15 is arranged on the vertically upper side nearer the joining end of the rear exhaust pipe 4, and is shaped extending toward the downstream small-diameter tube 3b of the auxiliary exhaust device 3.

[0033] The dropdown-preventing portion 15 is formed by a plate member of material (such as metal or engineering plastic, for example) that has good heat resistance. The tip end portion of the dropdown-preventing portion 15 has a semi-cylindrical shape that opens downward. The curvature radius of this semi-cylindrical portion 15a is set larger than the curvature radius of the rear exhaust pipe 4 and the downstream small-diameter tube 3b of the auxiliary exhaust device 3. This dropdown-preventing portion 15 is joined to the vertically upper side nearer the joining end of the rear exhaust pipe 4.

[0034] When this kind of dropdown-preventing portion 15 is provided, in the unlikely event that the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 separates, even though the rear exhaust pipe 4 would hang down forward with the support member 7 of the rear muffler 5 as the fulcrum or supporting point, the dropdown-preventing portion 15 arranged on the joining end of this rear exhaust pipe 4 would be caught (i.e., become hung up) in a manner covering the upper half of the downstream small-diameter tube 3b of the auxiliary exhaust device 3, as shown in FIG. 5.

[0035] Therefore, even though the joining end of the rear exhaust pipe 4 would hang down slightly, it would catch on (i.e., become hung up on) the auxiliary exhaust device 3, and would not hang down any further. As a result, even if the joint were to separate in this fashion, the joining end of the rear exhaust pipe 4 would not drag on the road surface, so the vehicle could be driven without any problem to a repair shop, for example.

[0036] As shown in FIG. 4, the separation dimension LI between both ends in the circumferential direction of the semi-cylindrical portion 15a is set larger than either of the separation dimensions Al and Bl between the downstream small-diameter tube 3b of the auxiliary exhaust device 3 and the inside surface of the upward arching concave portion 11 of the vehicle body 10.

[0037] When the dimensions are set in this way, even if the rear exhaust pipe 4 were to swing sideways while the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 is separated, as shown in FIG. 6, the dropdown-preventing portion 15 that is arranged at the joining end of this rear exhaust pipe 4 is prevented from slipping down from the separation portion of the downstream small-diameter tube 3b of the auxiliary exhaust device 3 and the inside surface of the upward arching concave portion 11 of the vehicle body 10.

[0038] As described above, in this example embodiment, even in the unlikely event that the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 separates, the joining end of the rear exhaust pipe 4 can be prevented from hanging down and dragging on the road surface. Moreover, the dropdown-preventing portion 15 is formed by a plate-shaped member, so a special part does not need to be used. As a result, the exhaust system can be provided at low cost.

[0039] The invention is not limited only to the example embodiment described above, but may be modified appropriately within the scope of the claims for patent and within a scope equivalent to that scope.

[0040] In the example embodiment described above, the dropdown-preventing portion 15 is formed in a semi-cylindrical shape, but the invention is not limited to this.

[0041] For example, the shape of the dropdown-preventing portion 15 may also simply be a flat shape as shown in FIG. 7. In this case as well, the overall width dimension LI in the sideways direction of the flat portion is preferably set larger than either of the separation dimensions Al and Bl between the downstream small-diameter tube 3b of the auxiliary exhaust device 3 and the inside surface of the upward arching concave portion 11 of the vehicle body 10, just as in the example embodiment described above.

[0042] Also, the dropdown-preventing portion 15 may be a curved rod-shaped member that is attached to the joining end of the rear exhaust pipe 4, in which the protruding end of this rod-shaped dropdown-preventing portion 15 is bent so as to catch on the downstream small-diameter tube 3b of the auxiliary exhaust device 3, as shown in FIG. 8, for example.

[0043] In the example embodiment described above, the dropdown-preventing portion 15 is arranged on the rear exhaust pipe 4, but the invention is not limited to this. For example, the dropdown-preventing portion 15 may be arranged on the auxiliary exhaust device 3 side, as shown in FIGS. 9 to 12.

[0044] In this case, the dropdown-preventing portion 15 is arranged on the vertically lower side of the auxiliary exhaust device 3, and is shaped extending toward the rear exhaust pipe 4. This dropdown-preventing portion 15 is formed from a plate-shaped member, with the tip end portion formed in a semi-cylindrical shape that opens upward. The curvature radius of this semi-cylindrical portion 15a is set larger than the curvature radius of the rear exhaust pipe 4 and the downstream small-diameter tube 3b of the auxiliary exhaust device 3.

[0045] When this kind of dropdown-preventing portion 15 is provided, in the unlikely event that the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 separates, even though the rear exhaust pipe 4 would hang down forward with the support member 7 of the rear muffler 5 as the fulcrum or supporting point, the joining end of the rear exhaust pipe 4 would be caught by (i.e., received by) the concave portion that opens upward of the dropdown-preventing portion 15 that is arranged on the lower side of the auxiliary exhaust device 3, as shown in FIG. 11.

[0046] Therefore, even though the joining end of the rear exhaust pipe 4 would hang down slightly, it would catch on the dropdown-preventing portion 15 that is arranged on the auxiliary exhaust device 3, and would not hang down any further. As a result, even if the joint were to separate in this fashion, the joining end of the rear exhaust pipe 4 would not drag on the road surface, so the vehicle could be driven without any problem to a repair shop, for example.

[0047] As shown in FIG. 10, if the separation dimension between one end in the circumferential direction of the semi-cylindrical portion 15a and a portion of the inside surface of the upward arching concave portion 11 of the vehicle body 10 that is closest to this end is designated A2, the separation dimension between the other end in the circumferential direction of the semi-cylindrical portion 15a and a portion of the inside surface of the upward arching concave portion 11 of the vehicle body 10 that is closest to this other end is designated B2, and the diameter dimension of the joining end of the rear exhaust pipe 4 is designated L2, the relationships among these are set such that A2 < L2 and B2 < L2.

[0048] When the dimensions are set in this way, even if the rear exhaust pipe 4 were to swing sideways while the rear joint 8b of the auxiliary exhaust device 3 and the rear exhaust pipe 4 is separated, as shown in FIG. 12, the dropdown-preventing portion 15 that is arranged at the joining end of this rear exhaust pipe 4 is prevented from slipping down from the separation portion of the dropdown-preventing portion 15 and the inside surface of the upward arching concave portion 11 of the vehicle body 10.

[0049] It should be noted that the dropdown-preventing portion 15 described in this example embodiment may also be flat or a rod-shaped, just as when the dropdown-preventing portion 15 is attached to the rear exhaust pipe 4.

[0050] The invention may be applied to an exhaust system that has an exhaust pipe attached to an engine, and an auxiliary exhaust device that is arranged midway in the exhaust pipe and suspended from the vehicle body, and in which at least one of an upper side and a lower side in the exhaust gas flow direction of the auxiliary exhaust device is joined to an exhaust pipe by welding.

Claims

CLAIMS:

1. An exhaust system comprising:

an exhaust pipe that is attached to an engine; and

an auxiliary exhaust device that is arranged midway in the exhaust pipe and is fixed to a vehicle body,

wherein at least one of an upstream side and a downstream side in an exhaust gas flow direction of the auxiliary exhaust device is joined to the exhaust pipe by welding, and a dropdown-preventing portion that hangs the exhaust pipe on the auxiliary exhaust device when a joint of the auxiliary exhaust device and the exhaust pipe separates, is provided on at least one of the auxiliary exhaust device and the exhaust pipe to which the auxiliary exhaust device is joined.

2. The exhaust system according to claim 1, wherein the auxiliary exhaust device is fixed suspended from the vehicle body.

3. The exhaust system according to claim 1 or 2, wherein the downstream side in the exhaust gas flow direction of the auxiliary exhaust device is joined to a rear exhaust pipe that is a downstream side portion of the exhaust pipe, and the dropdown-preventing portion is arranged on a vertically upper side of a joining end of the rear exhaust pipe and is shaped extending toward the auxiliary exhaust device.

4. The exhaust system according to claim 3, wherein the auxiliary exhaust device and the rear exhaust pipe are arranged in a non-contacting manner inside an upward arching concave portion that is arranged in a bottom portion of the vehicle body; a tip end portion on the auxiliary exhaust device side of the dropdown-preventing portion is formed in a semi-cylindrical shape that opens downward; and a separation dimension between both ends in a circumferential direction of the semi-cylindrically shaped portion is set larger than a separation dimension between a joining end on the downstream side in the exhaust gas flow direction of the auxiliary exhaust device and an inside surface of the upward arching concave portion.

5. The exhaust system according to claim 1, wherein the downstream side in the exhaust gas flow direction of the auxiliary exhaust device is joined to a rear exhaust pipe that is a downstream side portion of the exhaust pipe, and the dropdown-preventing portion is arranged on a vertically lower side of the auxiliary exhaust device and is shaped extending toward the rear exhaust pipe.

6. The exhaust system according to claim 5, wherein the auxiliary exhaust device and the rear exhaust pipe are arranged in a non-contacting manner inside an upward arching concave portion that is arranged in a bottom portion of the vehicle body; a tip end portion on the rear exhaust pipe side of the dropdown-preventing portion is formed in a semi-cylindrical shape that opens upward; and a separation dimension between one end in a circumferential direction of the semi-cylindrically shaped portion and a portion of an inside surface of the upward arching concave portion that is closest to the one end, and a separation dimension between the other end in the circumferential direction of the semi-cylindrically shaped portion and a portion of the inside surface of the upward arching concave portion that is closest to the other end, are set smaller than a diameter dimension of a joining end of the rear exhaust pipe.