Exhaust path structure

Abstract

To suppress height of an underfloor installation space of a vehicle and securely perform necessary discharge of condensation water generated inside.SOLUTION: An exhaust passage structure is installed in an underfloor space of a vehicle 100. An exhaust passage 1 comprises exhaust pipes 21, 22, 23 and silencers 31, 32 disposed in the middle. A lower end of the entire exhaust passage 1 is extended approximately horizontally, and an inclined water discharge passage 4 extended to a rear end part of the exhaust passage 1 and having a bottom part 41 gradually inclined downwardly toward the rear end part of the exhaust passage 1 is formed on the lower side of the exhaust passage 1. A capillary tube part 5 deriving condensation water from inside of the silencers 31, 32 to the inclined water discharge passage 4 is provided.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an exhaust passage structure that is attached to an underfloor space of a vehicle. [Background technology]

[0002] Conventionally, there has been known an exhaust passage structure for discharging exhaust gases generated by an internal combustion engine of an automobile to the outside. The exhaust passage structure is composed of, for example, a cylindrical exhaust pipe, a sub-silencer having a diameter larger than that of the exhaust pipe, a main silencer having a diameter larger than that of the exhaust pipe, and a tail end behind the main silencer. The exhaust pipe has a front end attached to a mounting member such as a catalytic converter and a rear end attached to the main silencer, and the sub-silencer is disposed midway along the exhaust passage. As shown in Figure 2 of Patent Document 1, the exhaust passage structure is installed in the underfloor space of a vehicle such as a four-wheeled automobile. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-76537 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, there is a demand for lower vehicle floors from the perspectives of improving vehicle ingress / egress ease, ensuring a larger interior space, and improving driving stability and ride comfort by lowering the vehicle's center of gravity.However, on the other hand, there is a trend toward adding components such as batteries in hybrid vehicles, and the space under the vehicle floor is becoming increasingly cramped.As a result, there is a demand for exhaust duct structures that can reduce the height of the installation space under the vehicle floor and facilitate lower vehicle floors.

[0005] In recent years, vehicles with cylinder deactivation, such as hybrid vehicles, and vehicles equipped with exhaust heat recovery devices are becoming more common, which reduces the temperature of the exhaust gas flowing through the exhaust duct. When the exhaust gas cools, the water vapor flowing through the exhaust duct turns into droplets and condenses, which accumulates inside the exhaust duct. This condensed water can freeze and clog the exhaust duct or cause corrosion, so it must be drained.

[0006] The present invention has been proposed in consideration of the above-mentioned problems, and aims to provide an exhaust duct structure that can reduce the height of the installation space under the floor of a vehicle and can reliably drain the necessary amount of condensed water that has formed inside. [Means for solving the problem]

[0007] The exhaust duct structure of the present invention is an exhaust duct structure installed in the underfloor space of a vehicle, and is characterized in that the exhaust duct is composed of an exhaust pipe and a silencer placed midway, the entire lower end of the exhaust duct extends approximately horizontally, a sloped drainage channel is formed below the exhaust duct, extending to the rear end of the exhaust duct and having a bottom that gradually slopes downward toward the rear end of the exhaust duct, and a capillary section is provided to guide condensed water from inside the silencer to the sloped drainage channel. This allows the lower end of the exhaust passage to extend substantially horizontally, thereby reducing the height of the installation space under the vehicle floor and facilitating a lower vehicle floor. Furthermore, by using the capillary tube to guide condensed water from the silencer, whose interior is partitioned and prone to condensation accumulation, to the inclined drainage channel, the necessary drainage of condensed water generated inside the exhaust passage can be ensured. This prevents exhaust passage blockage due to frozen condensed water and engine start failures resulting from such blockage. Furthermore, if the exhaust passage is made of metal, corrosion of the exhaust passage can be prevented. Furthermore, by extending the inclined drainage channel to the rear end of the exhaust passage, even if exhaust gas leaks into the inclined drainage channel from the location where the capillary tube is installed, the exhaust gas can be guided to a position corresponding to the rear end of the exhaust passage, eliminating the risk of exhaust gas being discharged under the vehicle entering the passenger compartment. In addition, by using a separate inclined drainage channel for draining condensed water from the exhaust channel, which becomes hot due to the exhaust, and by using thermocapillary action to guide the condensed water from the exhaust channel, which becomes hot due to the exhaust, to the low-temperature inclined drainage channel, the high-temperature exhaust gas being discharged can be effectively used as an energy source, and the condensed water can be actively and reliably drained without the need to supply additional energy.

[0008] The exhaust path structure of the present invention is characterized in that the capillary portion is curved so as to pass from near the rear end of the bottom plate of the silencer through the inside of the exhaust pipe downstream of the silencer and be led from the downstream exhaust pipe to the inclined drainage channel. This allows condensed water inside the silencer to be guided to the inclined drainage channel without forming a through-hole in the outer wall of the silencer, ensuring the silencer's required sound-absorbing performance. Furthermore, since the capillary tube is installed so that it curves upward and convexly, the installation state of the capillary tube can be stabilized. Furthermore, by utilizing the thermocapillary phenomenon and the siphon principle, the condensed water can be guided over the rear end wall of the silencer and into the inclined drainage channel, ensuring reliable drainage.

[0009] The exhaust path structure of the present invention is characterized in that the bottom plate of the silencer is formed to be inclined downward toward the condensed water introduction end of the capillary tube portion. This allows the condensed water to be efficiently collected at the inlet end of the capillary tube inside the silencer, and the condensed water can be drained so that the remaining amount is reduced.

[0010] The exhaust path structure of the present invention is characterized in that a capillary material that generates capillary action is installed inside a corrosion-resistant cylindrical holding material to form the capillary portion, the inner diameter of the cylindrical holding material is formed larger than the outer diameter of the capillary material, and the capillary material is held in place by a locking portion provided inside the cylindrical holding material. According to this, by forming a capillary section by installing a capillary material inside the cylindrical retaining member, it is possible to stably install the capillary section that directs condensed water from the inside of the silencer to the inclined drainage channel. Furthermore, by applying a corrosion-resistant treatment to the cylindrical retaining member, it is possible to extend the life of the cylindrical retaining member and the capillary section. Furthermore, by forming the inner diameter of the cylindrical retaining member larger than the outer diameter of the capillary material, it is possible to prevent the cylindrical retaining member from being compressed when the condensed water freezes and expands in volume.

[0011] The exhaust path structure of the present invention is characterized in that the cylindrical retaining material has high thermal conductivity of 16 W / m·K or more. According to this, by installing a capillary material inside a highly thermally conductive cylindrical holding material, if condensed water freezes inside the capillary section or inside the capillary material, the frozen condensed water can be melted using the high temperature energy of the exhaust gas and led to an inclined drainage channel for drainage.

[0012] The exhaust path structure of the present invention is characterized in that a drain hole is formed between the exhaust pipe and the inclined drainage channel to discharge condensed water from the exhaust pipe to the inclined drainage channel. With this, even if condensed water occurs in a part of the exhaust pipe other than the silencer, it can be smoothly discharged into the inclined drainage channel through the drainage hole and drained away.

[0013] The exhaust path structure of the present invention is characterized in that the entire exhaust path is formed in a flat shape that extends approximately horizontally. This makes it possible to more reliably obtain the internal cross-sectional area required for the exhaust pipe and the internal cross-sectional area required for the silencer while suppressing the height of the installation space under the floor of the vehicle.

[0014] The exhaust channel structure of the present invention is characterized in that the exhaust channel and the inclined drainage channel are formed of heat-resistant plastic. This allows the exhaust duct structure to be easily manufactured in any shape by adjusting the mold shape, thereby increasing the degree of freedom in the shape of the exhaust duct structure. Furthermore, since the exhaust duct structure is lighter than an exhaust duct structure made of a metal material, the resonant frequency of the exhaust duct structure can be increased, preventing the exhaust duct structure from deteriorating or being damaged by resonant vibrations. [Effects of the Invention]

[0015] According to the exhaust passage structure of the present invention, it is possible to reduce the height of the installation space under the floor of the vehicle, and also to reliably drain the necessary amount of condensed water generated inside. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view of an exhaust path structure according to an embodiment of the present invention, viewed from below. [Figure 2] FIG. 2 is a plan view of the exhaust path structure according to the embodiment. [Figure 3] FIG. 2 is a side view of the exhaust path structure according to the embodiment. [Figure 4] FIG. 2 is a bottom view of the exhaust passage structure according to the embodiment attached to a vehicle. [Figure 5] Cross section AA of Figure 2. [Figure 6] (a) is an enlarged view of part B in Figure 5, and (b) is an enlarged view of part C in Figure 5. [Figure 7] (a) and (b) are enlarged views corresponding to Fig. 6(a) and (b) of a modified exhaust passage structure in which the bottom plate of the silencer is inclined. [Figure 8] 10 is a cross-sectional view of an exhaust pipe portion in a modified exhaust passage structure in which drainage holes are formed between the exhaust pipe and the inclined drainage passage. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] [Exhaust path structure of embodiment] 1 to 6, an exhaust path structure according to an embodiment of the present invention is installed in the underfloor space of a vehicle 100, and comprises exhaust pipes 21, 22, and 23 arranged at intervals from the upstream side of the exhaust system, and a first silencer 31, a second silencer 32, and a third silencer 33 arranged at intervals from the upstream side of the exhaust system. The first silencer 31 is located between the exhaust pipes 21 and 22 and is provided midway through the exhaust path 1, and the second silencer 32 is located between the exhaust pipes 22 and 23 and is provided midway through the exhaust path 1. The third silencer 33 is located at the rear end of the exhaust path 1.

[0018] The exhaust pipes 21, 22, 23, the first silencer 31, the second silencer 32, and the third silencer 33 are each formed in a flat shape that extends approximately horizontally, and the entire exhaust path 1 is formed in a flat shape or a flat tubular shape that extends approximately horizontally. The lower end of the entire exhaust path 1, which is made up of the exhaust pipes 21, 22, 23, the first silencer 31, the second silencer 32, and the third silencer 33, is provided so as to extend approximately horizontally. In this embodiment, the exhaust pipes 22, 23, the second silencer 32, and the third silencer 33 are disposed above a bottom 41 of the inclined drainage channel 4, which will be described later, and the lower end of the first silencer 31 is formed so as to be approximately flush with the front end of the bottom 41 of the inclined drainage channel 4.

[0019] Below the exhaust passage 1, an inclined drainage channel 4 is formed as a separate route from the exhaust passage 1. The inclined drainage channel 4 extends to the rear end of the exhaust passage 1 and has a bottom 41 that gradually slopes downward toward the rear end of the exhaust passage 1. In this embodiment, the inclined drainage channel 4 is formed so as to extend from the rear end of the first silencer 31 to the rear end of the third silencer 33. The gradient of the bottom 41 of the inclined drainage channel 4 or the gradient of the inner bottom surface, which is the inclined surface of the bottom 41, is preferably 1 / 100 or more over the entire length of the inclined drainage channel 4 in order to allow condensed water in the inclined drainage channel 4 to move smoothly rearward.

[0020] In this embodiment, the exhaust path 1 and the inclined drainage path 4 are connected only at the location where the capillary section 5 described later is provided, and are isolated from each other by the bottom partition 11 of the exhaust path 1 at locations other than where the capillary section 5 is provided.

[0021] The exhaust channel structure consisting of the exhaust channel 1 and the inclined drainage channel 4, or the drainage channel 1 and the inclined drainage channel 4, is preferably made of heat-resistant plastic that can withstand the exhaust temperature, and more preferably made of heat-resistant plastic that can withstand a heat temperature of 150°C or more, but may also be made of metal material such as aluminum or brass, or either the exhaust channel 1 or the inclined drainage channel 4 may be made of heat-resistant plastic and the other of metal.

[0022] When the exhaust channel structure consisting of the drainage channel 1 and the inclined drainage channel 4 is made of a heat-resistant plastic such as polypropylene, for example, two halves are formed at a predetermined height of the exhaust channel 1, an upper half is formed, and the capillary tube portion 5 described later is fixed by fitting it into the sleeved through holes 12 and 13 while bending it as necessary, and the capillary tube portion 5 is fixed by fitting it into the sleeved through holes 14 and 15 while bending it as necessary, and then the upper half and the lower half are fixed by welding or adhesive, etc., which allows the capillary tube portion 5 to be easily and reliably attached to the predetermined position, and is preferable for improving manufacturing efficiency.

[0023] Furthermore, the exhaust path structure consisting of the drainage path 1 and the inclined drainage path 4 may be divided into two halves, left and right, and formed from heat-resistant plastic; the capillary portion 5 may be temporarily fixed by pressing it into the half of the sleeved through holes 12, 13 and the half of the sleeved through holes 14, 15, and then the left and right halves may be fixed by welding or adhesive, or the exhaust path structure main body other than the bottom 41 of the inclined drainage path 4 and the bottom 41 of a separate member may be formed from heat-resistant plastic; the capillary portion 5 may be fixed by fitting it into the sleeved through holes 12, 13 and the sleeved through holes 14, 15 of the exhaust path structure main body, respectively, and then the bottom 41 of the inclined drainage path 4, which is a separate member, may be fixed by welding or adhesive, etc.

[0024] Furthermore, even when either or both of the exhaust channel 1 and the inclined drainage channel 4 are formed from metal, the capillary portion 5 can be fixed to the sleeved through holes 12, 13 or the sleeved through holes 14, 15 using the same manufacturing process for the upper and lower halves, the left and right halves, or the bottom 41 of the inclined drainage channel 4, which is a separate member, as described above, and then the upper and lower halves, the left and right halves, or the bottom 41 of the inclined drainage channel 4, which is a separate member, can be fixed by adhesive, welding, etc.

[0025] A connecting pipe section 211, which is gradually deformed into a generally cylindrical shape toward the upstream side, is connected to the front side of the exhaust pipe 21, and a mounting flange 212 is provided at the front end of the connecting pipe section 211. Insertion holes are formed at intervals in the circumferential direction in the mounting flange 212. A flange is also provided at the rear end of a generally tubular connectable member 200, which is connected to the exhaust passage 1, and this flange also has insertion holes formed at intervals in the circumferential direction. The exhaust passage 1 and the connectable member 200 on the vehicle 100 are fixed and connected by aligning the insertion holes with the mounting flange 212 and abutting the flange, inserting bolts into the communicating insertion holes, and tightening the bolts and nuts, for example. The connectable member 200 may be any appropriate member within the spirit and scope of the present invention, and may be, for example, an exhaust heat recovery device or a downstream pipe fixedly connected to the downstream side thereof.

[0026] The first silencer 31 corresponds to a sub-silencer and is provided midway along the exhaust path 1, near the upstream side of the exhaust path 1. The first silencer 31 is formed in a flattened cylindrical shape that extends substantially horizontally, with its front and rear end faces closed, and its interior is hollow. Groups of through holes 312 are formed on the upper and lower surfaces of the substantially flattened cylindrical inner pipe portion 311 of the first silencer 31, and the group of through holes 312 connect an internal space 314 of the inner pipe portion 311 to a circumferential external space 315 between a housing 313 of the first silencer 31 and the inner pipe portion 311. The external space 315 is a continuous flattened cylindrical space that allows the exhaust gas to expand.

[0027] The first silencer 31 is provided with a capillary section 5 that directs condensed water from the inside of the first silencer 31 to the inclined drainage channel 4. The capillary section 5 is formed by fitting a capillary material 52 that generates capillary action inside a corrosion-resistant cylindrical holding member 51. The inner diameter of the cylindrical holding member 51 is slightly larger than the outer diameter of the capillary material 52, and the capillary material 52 is locked and held by a locking section 53 such as a locking claw provided inside the cylindrical holding member 51.

[0028] The cylindrical holding member 51 is preferably made of a highly thermally conductive material with a thermal conductivity of 16 W / m·K or higher, and metal materials such as aluminum with a corrosion-resistant surface or stainless steel such as austenitic stainless steel are suitable. Furthermore, when the capillary tube portion 5 is bent while being assembled into the exhaust path structure, it is preferable to use an easily flexible material such as aluminum. Furthermore, the capillary tube material 52 is preferably made of fiber materials such as glass fiber, carbon fiber, or aramid fiber, or twisted wire, or porous materials such as diatomaceous earth, foamed resin, or foamed rubber.

[0029] The capillary tube portion 5 provided in the first silencer 31 is curved so as to pass from near the rear end of the bottom plate 316 of the first silencer 31 or near the lower rear end wall 317 through the inside of the exhaust pipe 22 downstream of the first silencer 31 and lead from the downstream exhaust pipe 22 to the inclined drainage channel 4. The condensate inlet end 54 of the capillary tube portion 5 is located near the rear end of the bottom plate 316 of the first silencer 31, and the outlet end 55 is located, for example, near the bottom 41 of the inclined drainage channel 4. The capillary tube portion 5 is inserted through a sleeved through hole 12 formed in the inner pipe portion 311 of the first silencer 31 and a sleeved through hole 13 formed in the downstream exhaust pipe 22, and is fitted by being press-fitted into the sleeves of the sleeved through holes 12, 13. The capillary tube portion 5 can be fixed by any suitable method other than fitting, such as gluing the outer periphery.

[0030] The second silencer 32 corresponds to a sub-silencer, and is provided midway through the exhaust path 1, slightly upstream of the longitudinal midpoint of the exhaust path 1, and is disposed downstream of the first silencer 31 at a distance from the first silencer 31. Groups of through holes 322 are formed in the upper and lower surfaces of a substantially flattened cylindrical inner pipe portion 321 of the second silencer 32, and an internal space 324 of the inner pipe portion 321 and a circumferential external space 325 between a housing 323 of the second silencer 32 and the inner pipe portion 321 are connected by the group of through holes 322. The external space 325 is a continuous flattened cylindrical space that allows the exhaust gas to expand.

[0031] The second silencer 32 is also provided with a capillary tube 5 having the same configuration as above, which guides condensed water from inside the second silencer 32 to the inclined drainage channel 4. The capillary tube 5 provided in the second silencer 32 is curved so that it runs from near the rear end of the bottom plate 326 of the second silencer 32 or near the lower rear end wall 327, passes through the inside of the exhaust pipe 23 downstream of the second silencer 32, and is guided from the downstream exhaust pipe 23 to the inclined drainage channel 4. An inlet end 54 for condensed water of the capillary tube 5 is located near the rear end of the bottom plate 326 of the second silencer 32, and an outlet end 55 is located, for example, near the bottom 41 of the inclined drainage channel 4. The capillary tube portion 5 is inserted through a sleeved through-hole 14 formed in the inner pipe portion 321 of the second silencer 32 and a sleeved through-hole 15 formed in the downstream exhaust pipe 23, and is fitted so as to be press-fitted into the sleeves of the sleeved through-holes 14, 15. Note that the capillary tube portion 5 provided in the second silencer 32 can also be fixed by any suitable method other than fitting, as long as it is applicable.

[0032] The third silencer 33 corresponds to the main silencer, and is formed at the rear end of the exhaust passage 1 so as to taper in the width direction and in the height direction at an angle smaller than the width direction. The third silencer 33 also has a substantially flat cylindrical inner pipe portion installed up to a position upstream of the rear end, and a group of through holes formed in the upper and lower surfaces of the inner pipe portion communicates the internal space of the inner pipe portion with a circumferential external space (not shown) outside the inner pipe portion that functions as an expansion chamber.

[0033] Mounting plates 6·6 extend from the top to the sides of the exhaust duct 1 in the width direction. In this example, the mounting plates 6 are formed in the shape of elongated plates, with mounting holes 61 formed near their tips. When the exhaust duct 1 is made of heat-resistant plastic, the mounting plates 6 can be fixed to a predetermined location by adhesive or the like. However, it is more preferable to provide the mounting plates 6 integrally with the exhaust duct 1 or its constituent parts, for example, by injection molding using a heat-resistant synthetic resin of the same material, such as polypropylene. The mounting plates 6·6 are installed at multiple locations spaced apart along the length of the exhaust duct 2; in the illustrated example, the mounting plates 6·6 are installed at three locations spaced apart along the length of the exhaust duct 2.

[0034] The integrally formed exhaust duct 1 and inclined drainage channel 4 are attached to the underfloor space of the vehicle 100 by inserting fasteners such as screws or bolts into mounting holes 61 near the tip of the mounting plate portion 6 and fixing the tip of the fastener so that it is embedded in the mounting base 101. In the exhaust duct 1 and inclined drainage channel 4 attached in this manner, the inclined drainage channel 4 is positioned below the exhaust duct 1, and the bottom 41 of the inclined drainage channel 4 is inclined downward toward the rear of the vehicle 100.

[0035] According to the exhaust passage structure of this embodiment, by extending the lower end of the exhaust passage 1 substantially horizontally, the height of the installation space under the floor of the vehicle 100 can be reduced, and the vehicle 100 can be made lower in height. Furthermore, by guiding the condensed water from the first silencer 31 and the second silencer 32 provided in the exhaust passage 1, which is partitioned and prone to accumulate condensed water, to the inclined drainage passage 4 via the capillary tube section 5, it is possible to reliably drain the condensed water generated inside the exhaust passage 1 as needed. This makes it possible to avoid clogging of the exhaust passage 1 due to frozen condensed water and the inability to start the engine resulting from this clogging, and also prevents corrosion of the exhaust passage 1 if the exhaust passage 1 is made of metal.

[0036] Furthermore, by extending the inclined drainage channel 4 to the rear end of the exhaust passage 1, even if exhaust gas leaks into the inclined drainage channel 4 from the location where the capillary tube section 5 is installed, it can be guided to a position corresponding to the rear end of the exhaust passage 1, eliminating the risk of exhaust gas discharged under the vehicle entering the passenger compartment. Also, by making the inclined drainage channel 4 for draining condensed water a separate route from the exhaust passage 1 and guiding the condensed water from the exhaust passage 1, which becomes hot due to the exhaust, to the low-temperature inclined drainage channel 4 by thermocapillary action, the high-temperature exhaust gas discharged can be effectively used as an energy source, and the condensed water can be actively and reliably drained without supplying additional energy.

[0037] Furthermore, by installing the capillary tube portion 5 so as to curve from near the rear end of the bottom plate of the silencer 31, 32, through the inside of the exhaust pipes 22, 23 downstream of the silencer 31, 32, and guide the condensed water from the downstream exhaust pipes 22, 23 to the inclined drainage channel 4, condensed water inside the silencer 31, 32 can be guided to the inclined drainage channel 4 without forming a through-hole in the outer wall of the housing 313, 323 of the silencer 31, 32, thereby reliably achieving the required sound-absorbing performance of the silencer 31, 32. Furthermore, since the capillary tube portion 5 is installed so as to curve convexly upward, the installation state of the capillary tube portion 5 can be stabilized. Furthermore, by utilizing the thermocapillary phenomenon and the siphon principle, the condensed water can be guided over the rear end wall of the silencer to the inclined drainage channel 4, ensuring reliable drainage.

[0038] Furthermore, by forming the capillary section 5 by installing the capillary material 52 inside the cylindrical holding member 51, the capillary section 5 that directs condensed water from the inside of the first silencer 31 and the second silencer 32 to the inclined drainage channel 4 can be installed in a stable state. Furthermore, by performing a corrosion prevention treatment on the cylindrical holding member 51, the lifespan of the cylindrical holding member 51 and the capillary section 5 can be extended. Furthermore, by forming the inner diameter of the cylindrical holding member 51 larger than the outer diameter of the capillary material 52, it is possible to prevent the cylindrical holding member 51 from being compressed when the condensed water freezes and expands in volume.

[0039] Furthermore, by forming the cylindrical holding member 51 from a highly thermally conductive material with a thermal conductivity of 16 W / m·K or more and by incorporating the capillary material 52 into this highly thermally conductive cylindrical holding member 51, if condensed water freezes inside the capillary section 5 or inside the capillary material 52, the frozen condensed water can be melted using the high-temperature energy of the exhaust gas and led to the inclined drainage channel 4 for drainage.

[0040] Furthermore, by forming the entire exhaust duct 1 in a flat shape that extends approximately horizontally, it is possible to reduce the height of the installation space under the floor of the vehicle 100, while more reliably obtaining the internal cross-sectional area required for the exhaust pipes 21, 22, and 23 and the internal cross-sectional area required for the silencers 31, 32, and 33. Furthermore, when the exhaust duct 1 and the inclined drainage channel 4 are formed from heat-resistant plastic, the shape of the mold can be adjusted to easily manufacture an exhaust duct structure of any shape, increasing the degree of freedom in the shape of the exhaust duct structure, and since it is lighter than an exhaust duct structure formed from a metal material, the resonant frequency of the exhaust duct structure can be increased, preventing deterioration and damage to the exhaust duct structure due to resonant vibrations.

[0041] [Scope of the invention disclosed herein] The inventions disclosed in this specification include, in addition to the individual inventions and embodiments listed as inventions, those specified by modifying partial contents of these with other contents disclosed in this specification, those specified by adding other contents disclosed in this specification to these contents, or those specified by deleting partial contents of these to the extent that partial effects can be obtained and creating a generic concept. The inventions disclosed in this specification also include the following modifications and additions.

[0042] 7, for example, forming the bottom plates 316, 326 of the silencers 31, 32 so as to be inclined downward toward the condensed water inlet end 54 of the capillary tube section 5 is preferable because condensed water can be efficiently collected at the inlet end 54 of the capillary tube section 5 inside the silencers 31, 32 and drained to reduce the amount of remaining condensed water. The inclination of the bottom plates 316, 326 is preferably such that the position corresponding to the inlet end 54 of the capillary tube section 5 is lowest. For example, if the inlet end 54 of the capillary tube section 5 is located approximately in the center of the silencers 31, 32 in the width direction near the rear end walls 317, 327, the bottom plates 316, 326 should be inclined gradually downward toward the rear end and also gradually downward from both ends of the silencers 31, 32 in the width direction toward the center.

[0043] Furthermore, as shown in Figure 8, if drain holes 16 are formed in communication between the exhaust pipes 22, 23 and the inclined drainage channel 4 in addition to the capillary tube section 5, for discharging condensed water from the exhaust pipe 22 or the exhaust pipe 23 or both the exhaust pipes 22, 23 into the inclined drainage channel 4, even if condensed water occurs in parts of the exhaust pipes 22, 23 other than the silencers 31, 32, the water can be smoothly discharged and drained into the inclined drainage channel 4 through the drain holes 16, which is preferable.

[0044] Furthermore, in the exhaust path structure of the present invention, the number of exhaust pipes constituting the exhaust path and the silencers arranged along the way are appropriate, and the configuration of the exhaust pipes constituting the exhaust path and the silencers arranged along the way is appropriate within the applicable range. [Industrial Applicability]

[0045] The present invention can be used as an exhaust passage structure for exhaust gas emitted from an internal combustion engine of an automobile. [Explanation of symbols]

[0046] 1...Exhaust path 11...Bottom partition wall 12, 13, 14, 15...Through-hole with sleeve 16...Drainage hole 21, 22, 23...Exhaust pipe 211...Connecting pipe portion 212...Mounting flange 31...First silencer 311...Inner pipe portion 312...Through-hole group 313...Housing 314...Internal space 315...External space 316...Bottom plate 317...Rear end wall 32...Second silencer 321...Inner pipe portion 322...Through-hole group 323...Housing 324...Internal space 325...External space 326...Bottom plate 327...Rear end wall 33...Third silencer 4...Sloped drainage path 41...Bottom 5...Capillary portion 51...Cylindrical holding member 52...Capillary member 53...Engaging portion 54...Inlet end portion 55... Lead-out end portion 6... Mounting plate portion 61... Mounting hole 100... Vehicle 101... Mounted member 200... Connected member

Claims

1. An exhaust duct structure installed in an underfloor space of a vehicle, The exhaust path is composed of an exhaust pipe and a silencer placed midway. The entire lower end of the exhaust passage extends substantially horizontally, a sloped drainage channel is formed below the exhaust channel, extending to the rear end of the exhaust channel and having a bottom that slopes gradually downward toward the rear end of the exhaust channel; a capillary tube portion is provided to guide condensed water from the inside of the silencer to the inclined drainage channel; An exhaust path structure characterized in that the capillary portion is curved so as to pass from near the rear end of the bottom plate of the silencer through the inside of the exhaust pipe downstream of the silencer and be led from the downstream exhaust pipe to the inclined drainage channel.

2. 2. The exhaust passage structure according to claim 1, wherein the bottom plate of the silencer is formed to be inclined downward toward the condensed water introduction end of the capillary tube portion.

3. a capillary material that generates capillary action is installed inside a cylindrical holding member that has been subjected to anticorrosion treatment, thereby forming the capillary portion; The inner diameter of the cylindrical holding member is larger than the outer diameter of the capillary member, 3. The exhaust path structure according to claim 1, wherein the capillary tube is retained by a retaining portion provided inside the cylindrical retaining member.

4. 4. The exhaust path structure according to claim 3, wherein the cylindrical retaining member has a high thermal conductivity of 16 W / m·K or more.

5. An exhaust path structure as described in any one of claims 1 to 4, characterized in that a drain hole is formed between the exhaust pipe and the inclined drainage channel to discharge condensed water from the exhaust pipe to the inclined drainage channel.

6. 6. The exhaust path structure according to claim 1, wherein the entire exhaust path is formed in a flat shape that extends substantially horizontally.

7. 7. The exhaust passage structure according to claim 1, wherein the exhaust passage and the inclined drainage passage are formed from heat-resistant plastic.

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