JP5424054B2 - Vehicle exhaust system - Google Patents

Description

  The present invention relates to a vehicle exhaust device, and more particularly to a vehicle exhaust device that prevents muffler deformation and noise.

In a vehicle, a muffler is provided in an exhaust device in order to lower the temperature and pressure of exhaust gas from an engine. Among these mufflers, there is an expansion type structure including a plurality of expansion chambers that abruptly expand exhaust gas introduced from an inlet pipe to reduce the pressure and muffle it.
As shown in FIG. 9, in the expansion type muffler 101, the exhaust gas passing through the inlet pipe 102 first enters the expansion chamber 104 in which the inlet pipe 102 is inserted between the adjacent partition walls 103 and 103 among the plurality of expansion chambers. Therefore, in particular, the indoor temperature of the expansion chamber 104 into which the inlet pipe 102 is inserted tended to rise most as compared with other expansion chambers.

Japanese Utility Model Publication No. 6-18613

  The silencer (muffler) according to Patent Document 1 is provided with an intermediate plate only in a portion having a low rigidity (a large arc portion having a large curvature radius) between the inner peripheral shell and the outer peripheral shell to prevent deformation of the shell. Or reduce radiated sound.

By the way, in the conventional exhaust system of a vehicle, as shown in FIG. 9, the muffler 101 is caused by a temperature difference between the heat accumulated in the expansion chamber 104 into which the inlet pipe 102 is inserted and the air cooled outside the muffler 101. There is a problem that a large circular arc portion having the lowest curvature radius and the lowest rigidity among the shell 107 composed of the inner circumferential shell 105 and the outer circumferential shell 106 is deformed. In this case, due to the heat of the exhaust gas, the inner peripheral shell 105 exposed to the high temperature exhaust gas is deformed more greatly than the outer peripheral shell 106 exposed to the external low temperature atmosphere, and the inner peripheral shell 105 and the outer peripheral shell A gap S was formed between the two and 106.
Then, as shown in FIG. 9, when the temperature inside the muffler 101 is lowered and the deformation of the muffler 101 returns to the original state after the engine is stopped, the inner peripheral shell 105 is contracted from the expanded state. Therefore, there is a problem that the inner peripheral shell 105 and the outer peripheral shell 106 collide with each other due to the change of the shape or the contraction of the inner peripheral shell 105, and abnormal noise is generated.
Therefore, also in the above-mentioned Patent Document 1, a difference in thermal expansion occurs between the outer peripheral shell cooled by the traveling wind and the inner peripheral shell heated by the heat of the exhaust gas inside the muffler. Due to the difference in the amount of expansion, there is a problem that the shells are separated (between the inner peripheral shell and the intermediate plate and between the intermediate plate and the outer peripheral shell), the rigidity is lowered, and the surface of the muffler is deformed.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle exhaust device that eliminates the difference in thermal expansion between the inner peripheral side and the outer peripheral side of the muffler and prevents the muffler from deforming and generating abnormal noise.

  According to the present invention, an elliptical muffler body having a cross-sectional shape in which both ends of a large arc part are connected by a small arc part is disposed at the lower part of the vehicle with the cross section directed in the vehicle width direction, and the outer wall of the muffler body is a thin plate. A cylindrical shell wound in layers and an end plate that closes both axial ends of the shell are formed, and a plurality of expansion chambers defined by partition walls are formed in the shell. In an exhaust system for a vehicle having a structure in which an inlet pipe for introducing exhaust gas is inserted into the expansion chamber through a small arc portion of the shell and a reinforcing plate joined to an outer peripheral surface of the small arc portion, A plate member extending along the outer peripheral surface of the large arc portion is provided on the large arc portion of the shell constituting the outer wall of the expansion chamber into which the inlet pipe is inserted, and the plate member is connected to the reinforcing plate. .

  The vehicle exhaust system according to the present invention can eliminate the difference in thermal expansion between the inner peripheral side and the outer peripheral side of the muffler, and can prevent the muffler from deforming and generating abnormal noise.

FIG. 1 is a bottom view of the vehicle. (Example) FIG. 2 is a left side view of the vehicle. (Example) FIG. 3 is a bottom view of the muffler. (Example) 4 is a cross-sectional view taken along line IV-IV in FIG. (Example) FIG. 5 is a cross-sectional view taken along line VV in FIG. (Example) 6 is an enlarged cross-sectional view taken along arrow VI in FIG. (Example) FIG. 7 is a bottom view of the muffler. (Modification) 8 is a cross-sectional view taken along line VIII-VIII in FIG. (Modification) FIG. 9 is a cross-sectional view showing a deformed state of a conventional shell. (Conventional example)

  This invention constitutes the outer wall of the expansion chamber into which the inlet pipe is inserted for the purpose of eliminating the difference in the thermal expansion amount between the inner peripheral side and the outer peripheral side of the muffler and preventing the muffler from deforming and generating abnormal noise. A plate member extending along the outer peripheral surface of the large arc portion is provided in the large arc portion of the shell, and the plate member is used to improve the surface rigidity of the large arc portion.

1 to 6 show an embodiment of the present invention.
1 and 2, 1 is a vehicle, 2L is a left front wheel, 2R right front wheel, 3L is a left rear wheel, 3R right rear wheel, 4L is a left side member, and 4R is a right side member.
The vehicle 1 is equipped with an engine 5 at the front and an exhaust device 6 that discharges exhaust gas from the engine 5.
The exhaust device 6 includes an exhaust pipe 8 connected to the engine 5 and extending rearward of the vehicle and provided with a catalytic converter 7, an inlet pipe 9 connected to a rear end of the exhaust pipe 8, and an outlet extending rearward of the vehicle from the right side. A muffler 12 provided with a pipe 10 is provided below the rear floor 11 and between the left rear wheel 3L and the right rear wheel 3R.
As shown in FIGS. 1 and 4, the muffler 12 includes a front support rod 13F and a rear support rod 13B fixed to the muffler 12, and a front mount rubber locked to the front ends of the front support rod 13F and the rear support rod 13B. The rear floor 11 is elastically supported by the 14F / rear mounting rubber 14B and the front mounting pins 15F and the rear mounting pins 15B fixed to the rear floor 11 by being locked to the front mounting rubber 14F / rear mounting rubber 14B.

As shown in FIGS. 3 to 6, the muffler 12 is an elliptical muffler having a cross-sectional shape in which both ends of an upper large arc portion 16U and a lower large arc portion 16D are connected by a front small arc portion 17F and a rear small arc portion 17B. A main body 18 is provided, and the muffler main body 18 is disposed below the rear floor 11, which is the lower part of the vehicle 1, with the cross section of the muffler main body 18 facing the vehicle width direction (the vehicle left-right direction).
The outer wall of the muffler body 18 has a cylindrical shell 21 composed of an inner peripheral shell 19 and an outer peripheral shell 20 in which thin plates are wound in layers, and left and right left ends that close both axial ends of the shell 21. The plate 22L and the right end plate 22R are formed.

As shown in FIG. 5, in the shell 21, as a plurality of expansion chambers, first to fifth expansions are performed by first to fourth partition walls 23 to 26, a left end plate 22L and a right end plate 22R which are sequentially arranged from the left side. The chambers 27 to 31 are partitioned.
The first expansion chamber 27 is formed by the left end plate 22 </ b> L and the first partition wall 23 having a plurality of left vent holes 32. The second expansion chamber 28 is formed by the first partition wall 23 and the second partition wall 24 not provided with a vent hole. The third expansion chamber 29 is disposed at the central portion of the muffler body 18 and is formed by the second partition wall 24 and the third partition wall 25 that is not provided with a vent hole. The fourth expansion chamber 30 is formed by the third partition wall 25 and the fourth partition wall 26 having a plurality of right vent holes 33. The fifth expansion chamber 31 is formed by the fourth partition wall 26 and the right end plate 22R.

The muffler main body 18 has an inlet pipe 9 having a lower end portion opened in the third expansion chamber 29 so that the exhaust from the engine 5 is introduced into the third expansion chamber 29 in the central portion as one expansion chamber. It is attached.
In the muffler body 18, a first short-circuit pipe 34 that directly guides the exhaust gas from the third expansion chamber 29 to the fifth expansion chamber 31 is attached to the third partition wall 25 and the fourth partition wall 26. A second short-circuit pipe 35 that directly guides the exhaust gas in the expansion chamber 30 to the second expansion chamber 28 is attached to the second partition wall 24 and the third partition wall 25, and an outlet pipe having a distal end opening in the second expansion chamber 28. 10 is attached to the second partition wall 24 to the fourth partition wall 26 and the right end plate 22R.
In the muffler 12, as shown in FIGS. 3 and 4, the inlet pipe 9 for introducing exhaust gas into the third expansion chamber 29, which is one of the expansion chambers 25 to 31, is connected to the small arc of the shell 21. The structure is such that the front small arc portion 17F as a portion and the reinforcing plate 36 joined to the outer peripheral surface of the front small arc portion 17F are inserted into the third expansion chamber 29.

As shown in FIGS. 3 to 6, the lower large arc portion 16 </ b> D of the shell 21 constituting the outer wall of the third expansion chamber 29 into which the inlet pipe 9 is inserted has a plate along the outer peripheral surface of the lower large arc portion 16 </ b> D. A member 37 is joined and provided, and the plate member 37 is connected to the reinforcing plate 36 by a connecting portion 38.
Thus, by joining the plate member 37 along the outer peripheral surface of the lower large arc portion 16D to the lower large arc portion 16D constituting the outer wall of the third expansion chamber 29 into which the inlet pipe 9 is inserted, The plate member 37 can improve the surface rigidity of the lower large arc portion 16D.
Further, the plate member 37 is placed along the outer peripheral surface of the lower large circular arc portion 16D, and the plate member 37 is connected to the reinforcing plate 36, thereby reinforcing the heat of the exhaust gas of the inlet pipe 9 that has become hot due to the passage of the exhaust gas. The heat transmitted to the plate member 37 can be transmitted from the plate 36 to the plate member 37, and then transmitted to the outer peripheral side shell 20 that becomes the outer peripheral surface of the shell 21 through the plate member 37.
As a result, the outer shell 20 as the outer peripheral surface of the shell 21 cooled by the traveling air flowing around the muffler 12 (outer periphery) and the shell 21 heated by the heat of the exhaust gas accumulated in the third expansion chamber 29 The difference in the amount of thermal expansion from the inner peripheral side shell 19 serving as the peripheral surface is eliminated, and the amount of thermal expansion between the inner peripheral side shell 19 and the outer peripheral side shell 20 composed of these two layers (or a plurality of layers) is substantially equal. It is possible to improve the surface rigidity of the lower large arc portion 16D by maintaining a close contact between the inner peripheral shell 19 and the outer peripheral shell 20. That is, the plate member 37 has not only a function of a reinforcing plate for the shell 21 but also a function of a heat transfer plate for transferring heat to the outer peripheral surface of the shell 21, so that two layers (or , A close contact state between the inner shell 19 and the outer shell 20 composed of a plurality of layers) can be improved, and deformation of the shell 21 can be suppressed.
Accordingly, when the temperature inside the muffler 12 decreases due to the stop of the engine 5 and the deformation of the shell 21 is restored, the generation of abnormal noise caused by the collision / contact between the inner shell 19 and the outer shell 20 is prevented. can do.

As shown in FIG. 4, the connecting portion 38 of the plate member 37 that is connected to the reinforcing plate 36 extends to the periphery of the outer peripheral surface of the inlet pipe 9.
With such a structure, the heat of the inlet pipe 9 that has become high temperature due to the passage of exhaust gas can be directly received by the plate member 37. As a result, the plate member 37 is heated by the inlet pipe 9, and the difference in surface temperature between the inner peripheral side shell 19 and the outer peripheral side shell 20 of the shell 21 is eliminated. The amount of thermal expansion of the side shell 20 can be made uniform.

Further, the plate member 37 is provided in close contact with the outer peripheral surface of the shell 21. Thus, the plate member 37 is brought into close contact with the outer peripheral surface of the shell 21, whereby the heat of the plate member 37 can be directly transmitted to the outer peripheral surface of the shell 21.
Thereby, the heat transfer coefficient flowing from the plate member 37 to the outer peripheral surface of the shell 21 can be increased, and the outer peripheral side shell 20 as the outer peripheral surface of the shell 21 can be prevented from being contracted by the traveling wind.

As a modification of this embodiment, as shown in FIGS. 7 and 8, the muffler 12 in which the upper large arc portion 16U and the lower large arc portion 16D are arranged on the upper side and the lower side in the vertical direction of the muffler body 18. The plate member 37 is attached to at least the lower large arc portion 16D on the lower side in the vertical direction of the muffler body 18 among the upper large arc portion 16U and the lower large arc portion 16D. The plate member 37 includes a bulging portion 40 formed by a step portion 39, and a predetermined space 41 is formed between the bulging portion 40 and the outer peripheral surface of the shell 21. In this space 41, the heat from the bulging part 40 is transmitted toward the inner side.
In general, a high-speed traveling wind passes under the muffler 12, so that the lower part of the muffler 12 is rapidly cooled by the passage of the traveling wind. In particular, in the lower part of the muffler 12, The temperature difference between the inner shell 19 and the outer shell 20 increases, and the difference in thermal expansion between the inner shell 19 and the outer shell 20 increases, and the closeness between the inner shell 19 and the outer shell 20 increases. descend.
Therefore, in this modification, the plate member 37 is attached to at least the lower large arc portion 16D on the lower side in the vertical direction of the upper large arc portion 16U and the lower large arc portion 16D, so that traveling at a high speed below the muffler 12 is performed. The outer peripheral surface of the shell 21 that is rapidly cooled by the wind is heated by the plate member 37, and in particular, the difference in thermal expansion between the inner peripheral side shell 19 and the outer peripheral side shell 20 that occurs below the muffler 12 is eliminated, The deformation of the shell 21 at the lower part of the muffler 12 can be prevented.

  The exhaust device according to the present invention can be applied to various vehicles.

DESCRIPTION OF SYMBOLS 1 Vehicle 5 Engine 6 Exhaust device 8 Exhaust pipe 9 Inlet pipe 10 Outlet pipe 12 Muffler 16U Upper large circular arc part 16D Lower large circular arc part 17F Front small circular arc part 17R Rear small circular arc part 18 Muffler main body 19 Inner peripheral side shell 20 Outer peripheral side shell 21 Shell 22L Left end plate 22R Right end plate 23-26 1st-4th partition 27-31 1st-5th expansion chamber 36 Reinforcement plate 37 Plate member 38 Connection part

Claims (4)

  An elliptical muffler body with a cross-sectional shape connecting both ends of a large arc part with a small arc part is placed at the lower part of the vehicle with the cross section facing in the width direction of the vehicle, and the outer wall of the muffler body is laminated with thin plates in layers A cylindrical shell and an end plate that closes both axial ends of the shell, a plurality of expansion chambers defined by partition walls are formed in the shell, and exhaust gas is provided in one of the expansion chambers. In an exhaust system for a vehicle having a structure in which an inlet pipe for introducing a pipe is inserted into the expansion chamber through a small arc portion of the shell and a reinforcing plate joined to an outer peripheral surface of the small arc portion, A vehicle exhaust characterized in that a plate member is provided along the outer peripheral surface of the large arc portion at the large arc portion of the shell constituting the outer wall of the expansion chamber to be inserted, and the plate member is connected to the reinforcing plate. Location.   2. The vehicle exhaust device according to claim 1, wherein a portion of the plate member connected to the reinforcing plate extends to the periphery of the outer peripheral surface of the inlet pipe.   The exhaust device for a vehicle according to claim 2, wherein the plate member is brought into close contact with an outer peripheral surface of the shell.   In the muffler in which the large arc portion is arranged on the upper and lower sides in the vertical direction of the muffler body, the plate member is attached to at least the large arc portion on the lower side in the vertical direction of the muffler body among the large arc portions. The vehicle exhaust device according to claim 3, wherein the vehicle exhaust device is provided.

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