Vehicle exhaust system

Abstract

To provide an exhaust system that has a high degree of freedom in layout even in a narrow space and can achieve a long tail layout.SOLUTION: Provided is a vehicle exhaust system having an upstream end connected to an internal combustion engine mounted on a vehicle and having an exhaust port formed at a downstream end arranged at a rear end side of the vehicle, including: a first exhaust pipe connected to the internal combustion engine and extending to a rear side of the vehicle; a first turning part connected to a downstream end of the first exhaust pipe and turning to a front side of the vehicle; a second exhaust pipe connected to a downstream end of the first turning part and extending to the front side of the vehicle; a second turning part connected to a downstream end of the second exhaust pipe and turning to the rear side of the vehicle; a third exhaust pipe connected to a downstream end of the second turning part and extending to the rear side of the vehicle; and a main muffler interposed halfway in the second exhaust pipe.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exhaust system mounted on a vehicle. [Background technology]

[0002] The layout of an exhaust system for an internal combustion engine mounted on a general passenger vehicle is, as shown in FIG. 20, an exhaust system 1 that extends in the front-rear direction (FR-RR direction) of a vehicle (not shown), and its front end is connected to and fixed to an internal combustion engine (specifically, an exhaust port of the internal combustion engine or an exhaust manifold, a supercharger, an exhaust purification device, or other internal combustion engine accessories) (not shown). On the other hand, an exhaust port 2 that is the rear end of the exhaust system 1 is generally disposed at the rear of the vehicle. In addition, a main muffler 3 that performs the function of silencing exhaust noise is interposed in an exhaust pipe 4 located at the rear of the vehicle. Furthermore, although not shown, a sub-muffler and / or an exhaust purification device (for example, various catalytic converters and / or filter devices such as a diesel particulate filter (DPF) or a gasoline particulate filter (GPF)) are interposed at appropriate locations as a countermeasure against standing waves. The exhaust system 1 having such a configuration is suspended from the vehicle by suspension devices (not shown) (for example, support rods and support rubbers) provided at a plurality of locations.

[0003] From the viewpoint of increasing the silencing efficiency of the entire exhaust system (from the front end connected to the internal combustion engine to the rear end which is the exhaust port), it is preferable to arrange the main muffler at position A where an antinode appears in the vibration mode of a standing wave in the entire exhaust system. Fig. 21 is a schematic diagram showing an example of a standing wave that appears in an exhaust pipe through which exhaust flows (see the white arrow). As illustrated in Fig. 21, by arranging the main muffler at position A where an antinode appears in the vibration mode of a standing wave, even a main muffler with a small capacity can efficiently muffle noise. Specifically, for example, it is preferable to arrange the main muffler at the middle position of the exhaust system (middle between the front end and the rear end).

[0004] It is also known that by arranging a long exhaust pipe downstream of the main muffler in the exhaust system (hereinafter, such an arrangement may be referred to as a "long-tail layout"), it is possible to muffle low frequencies (around 100 Hz), which are the main cause of resonance noise in the passenger compartment of a vehicle (hereinafter, sometimes referred to as "booming noise"). Figure 22 is a conceptual graph illustrating the difference in muffled sound depending on the length of the tailpipe. As illustrated in Figure 22, when a long tailpipe is used (see graph A with a thick solid line), the distribution of muffled sound with respect to frequency is shifted to the low-frequency side compared to when a short tailpipe is used (see graph B with a thin dashed line). In fact, a long-tail layout is used in some vehicles.

[0005] However, since the vicinity of the middle position of the exhaust system is often under the floor of the passenger compartment of the vehicle, it is difficult to place the main muffler, which is a (large) element having a large capacity among the components of the exhaust system, in that position, and it is common to have no choice but to place the main muffler near the rear end of the vehicle (in front of the rear bumper). In such a placement, as in position B shown in Figure 21, the main muffler is placed near the position where a node appears rather than an antinode in the vibration mode of the standing wave, making it difficult to achieve a sufficient silencing effect.

[0006] In particular, in today's electric vehicles (so-called "HEVs" and "PHEVs," etc.) that are equipped with a combination of an internal combustion engine and a motor / generator, the drive battery is sometimes located in the entire area under the floor of the vehicle's passenger compartment, and in some cases in an area that extends from under the floor of the passenger compartment to the rear end of the vehicle. Also, since it is necessary to install a motor / generator in addition to the internal combustion engine and fuel tank, the free space in the vehicle as a whole is becoming smaller, making it increasingly difficult to realize a long tail (i.e., the freedom of layout of the exhaust system is being reduced).

[0007] On the other hand, in order to improve the degree of freedom in the layout of the exhaust system, a layout that extends the exhaust system not only in the longitudinal direction of the vehicle but also in the lateral direction has been proposed. For example, in the exhaust system of an HEV disclosed in Patent Document 1 (JP Patent Publication No. 2013-528518), an exhaust pipe extends rearward from an internal combustion engine mounted at the front of the vehicle, and its rear end is branched and extends to both sides of the vehicle, with a main muffler interposed between each, and the rear end opens toward both sides of the vehicle.

[0008] Also, in the exhaust system of an internal combustion engine disclosed in Patent Document 2 (U.S. Pat. No. 5,388,408), an exhaust pipe 16 extending rearward is branched at its rear end into exhaust pipes 22a and 22b extending to both sides of the vehicle, and these are further connected via exhaust pipes 24a and 24b extending forward to silencer chambers 26 serving as main mufflers mounted on both sides of the vehicle in the fore-and-aft direction.

[0009] However, all of these conventional exhaust systems have a special layout in which the main muffler and exhaust port are located at the front of the vehicle (forward of the rear wheels), and are not suitable for general passenger vehicles. In addition, none of the exhaust systems guarantees the realization of a long-tail layout; rather, it is difficult to realize a long-tail layout with any of the exhaust systems.

[0010] As described above, there is a demand in this technical field for an exhaust system that allows for a high degree of freedom in layout even in a small space and enables a long-tail layout. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 2013-528518 [Patent Document 2] U.S. Pat. No. 5,388,408 [Patent Document 3] Patent No. 7089628 Summary of the Invention [Problem to be solved by the invention]

[0012] As described above, there is a demand in the art for an exhaust system that allows high degree of freedom in layout even in a small space and allows for a long-tail layout. The present invention has been made to meet such demands. [Means for solving the problem]

[0013] In consideration of the above problems, the inventor has conducted intensive research and has found that the above problems can be solved by providing an exhaust system for a vehicle, the exhaust system having an upstream end connected to an internal combustion engine mounted on the vehicle and communicating with an exhaust port located at the rear end of the vehicle, the exhaust system comprising a first exhaust pipe connected to the internal combustion engine and extending to the rear of the vehicle, a first turning portion connected to the rear end of the first exhaust pipe and turning to the front of the vehicle, a second exhaust pipe connected to the rear end of the first turning portion and extending to the front of the vehicle, a second turning portion connected to the rear end of the second exhaust pipe and turning to the rear of the vehicle, and a third exhaust pipe connected to the rear end of the second turning portion and extending to the rear of the vehicle, and by interposing a main silencer midway through the second exhaust pipe.

[0014] Specifically, the vehicle exhaust system according to the present invention (hereinafter, sometimes referred to as the "system of the present invention") is an exhaust system of a vehicle whose upstream end is connected to an internal combustion engine mounted on the vehicle and whose downstream end is formed with an exhaust port disposed at the rear end of the vehicle. The system of the present invention comprises, in order from upstream to downstream in the exhaust flow, a first exhaust pipe, a first turning portion, a second exhaust pipe, a second turning portion, a third exhaust pipe, and a main silencer.

[0015] The first exhaust pipe is a member connected to the internal combustion engine and extending to the rear of the vehicle. The first turning portion is a member connected to the downstream end of the first exhaust pipe and turning to the front of the vehicle. The second exhaust pipe is a member connected to the downstream end of the first turning portion and extending to the front of the vehicle. The second turning portion is a member connected to the downstream end of the second exhaust pipe and turning to the rear of the vehicle. The third exhaust pipe is a member connected to the downstream end of the second turning portion and extending to the rear of the vehicle. The main silencer is interposed midway through the second exhaust pipe. Effect of the Invention

[0016] As described above, in the system of the present invention, the exhaust path from the internal combustion engine mounted on the vehicle to the exhaust port located at the rear end of the vehicle is configured to be approximately S-shaped or approximately Z-shaped. Therefore, each component (the first exhaust pipe to the third exhaust pipe and the first turning portion and the second turning portion) can be arranged three-dimensionally in the front-rear (longitudinal) direction, left-right (width) direction, and vertical (height) direction of the vehicle, allowing for a high degree of freedom in layout. As a result, a long and large exhaust path can be arranged even in a small space (determined by the design specifications of the vehicle).

[0017] In addition, in the system of the present invention, the main silencer is interposed in the middle of the second exhaust pipe out of the three exhaust pipes included in the exhaust path. Therefore, it is easy to arrange the main silencer in an intermediate position in the exhaust path, and a long-tail layout can be easily realized. In other words, according to the system of the present invention, it is possible to provide an exhaust system that allows high degree of freedom in layout even in a small space and allows a long-tail layout to be realized.

[0018] Other objects, features and attendant advantages of the present invention will become readily apparent from the following description of the embodiments of the present invention which are given with reference to the accompanying drawings. [Brief description of the drawings]

[0019] [Figure 1]FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle exhaust system (first system) according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of the configuration of a first system in which an exhaust port is arranged to face the side of the vehicle. [Diagram 3] FIG. 2 is a schematic diagram showing an example of the configuration of a first system in which a catalytic converter as an exhaust purification device is installed midway through a first exhaust pipe. [Figure 4] FIG. 4 is a schematic diagram showing an example of the configuration of a first system in which a sub-muffler is installed midway through a third exhaust pipe. [Diagram 5] 1 is a schematic diagram illustrating the configuration of a conventional exhaust system in which a main silencer is mounted on the rear overhang of a vehicle; [Figure 6] FIG. 11 is a schematic diagram showing an example of the configuration of a vehicle exhaust system (second system) according to a second embodiment of the present invention. [Figure 7] FIG. 13 is a schematic diagram showing an example of the configuration of a second system in which an exhaust port is arranged to face the side of the vehicle. [Figure 8] FIG. 4 is a schematic diagram showing an example of the configuration of a second system in which a catalytic converter as an exhaust purification device is installed midway through a first exhaust pipe. [Figure 9] FIG. 13 is a schematic diagram showing an example of the configuration of a second system in which a sub-muffler is interposed midway through each of two third exhaust pipes constituting two exhaust units. [Figure 10] FIG. 13 is a schematic diagram showing an example of the configuration of a second system in which there are sets of a first exhaust pipe, a second exhaust pipe, and a third exhaust pipe that are not parallel to each other. [Figure 11] FIG. 11 is a schematic diagram showing an example of the configuration of a second system in which a third exhaust pipe passes above a second exhaust pipe in the vertical (height) direction of a vehicle. [Figure 12] FIG. 13 is a schematic diagram showing an example of the configuration of a second system in which a sub-muffler is interposed midway through each of two third exhaust pipes constituting two exhaust units. [Figure 13] FIG. 11 is a schematic diagram showing an example of the configuration of a vehicle exhaust system (third system) according to a third embodiment of the present invention. [Figure 14] FIG. 13 is a schematic diagram showing an example of the configuration of a third system having two exhaust units. [Figure 15] FIG. 13 is a schematic diagram showing an example of the configuration of a third system in which an exhaust port is arranged to face the side of the vehicle. [Figure 16] FIG. 4 is a schematic diagram showing an example of the configuration of a third system in which a catalytic converter as an exhaust purification device is installed midway through a first exhaust pipe. [Figure 17] FIG. 13 is a schematic diagram showing an example of the configuration of a third system in which a sub-muffler is interposed midway through each of two third exhaust pipes constituting two exhaust units. [Figure 18] FIG. 11 is a schematic diagram showing an example of the configuration of a third system in which a third exhaust pipe passes above the second exhaust pipe in the vertical (height) direction of the vehicle. [Figure 19] FIG. 13 is a schematic diagram showing an example of the configuration of a third system in which a sub-muffler is interposed midway through each of two third exhaust pipes constituting two exhaust units. [Figure 20] 1 is a schematic perspective view illustrating a layout of an exhaust system of an internal combustion engine mounted in a typical passenger vehicle. [Figure 21] FIG. 1 is a schematic diagram showing an example of a standing wave that appears in an exhaust pipe through which exhaust gas flows. [Figure 22] 1 is a conceptual graph illustrating a difference in muffling volume depending on the length of a tailpipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First Embodiment Hereinafter, a vehicle exhaust system according to a first embodiment of the present invention (hereinafter, may be referred to as a "first system") will be described with reference to the drawings.

[0021] <composition> The first system is an exhaust system for a vehicle in which an upstream end is connected to an internal combustion engine mounted on the vehicle and an exhaust port formed at a downstream end is disposed at the rear end of the vehicle. The internal combustion engine to which the first system is applied is not necessarily limited to one used as a driving source of the vehicle, but may be any internal combustion engine mounted on a vehicle. In other words, the vehicle to which the internal combustion engine to which the first system is applied is not particularly limited, and the first system can be applied to internal combustion engines mounted on a wide variety of vehicles, such as vehicles in which the internal combustion engine is used only for driving, electric vehicles in which the internal combustion engine and an electric motor are combined and used for driving, (e.g., HEV and PHEV, etc.), and electric vehicles in which the internal combustion engine is used only for driving a generator, (e.g., series hybrid vehicles and vehicles equipped with a range extender, etc.). In addition, the fuel for the internal combustion engine is not limited to gasoline or diesel, and hydrogen or various alternative fuels can be selected.

[0022] Regarding the mounting position of the internal combustion engine, the so-called "horizontal mounting" in which the crankshaft is arranged at right angles to the front-to-rear direction of the vehicle has a high affinity with the first system, but the first system can also be applied to an internal combustion engine that is "vertical mounting". Furthermore, regarding the mounting position of the internal combustion engine in the vehicle, the first method can be applied to any of the following: the front of the vehicle (bonnet), the middle of the vehicle (midship; the section from the wheelbase (between the front and rear wheels) to the top of the rear wheels), or the rear of the vehicle (behind the rear wheels). Among these, the first new stem has a particularly high affinity with internal combustion engines mounted in the middle or rear of the vehicle.

[0023] The first system includes, in order from the upstream side to the downstream side in the exhaust flow, a first exhaust pipe, a first turning portion, a second exhaust pipe, a second turning portion, a third exhaust pipe, and a main silencer. The first exhaust pipe is a member connected to the internal combustion engine and extending toward the rear of the vehicle. The first turning portion is a member connected to the downstream end of the first exhaust pipe and turning toward the front of the vehicle. The second exhaust pipe is a member connected to the downstream end of the first turning portion and extending toward the front of the vehicle. The second turning portion is a member connected to the downstream end of the second exhaust pipe and turning toward the rear of the vehicle. The third exhaust pipe is a member connected to the downstream end of the second turning portion and extending toward the rear of the vehicle. The main silencer is interposed midway through the second exhaust pipe.

[0024] The first turning portion and the second turning portion are members having a substantially U-shaped configuration, and may be integrated with the adjacent exhaust pipe, or may be separate from the adjacent exhaust pipe and connected to the adjacent exhaust pipe by means of welding or the like. When the first turning portion and / or the second turning portion are integrated with the adjacent exhaust pipe, the boundary between the adjacent exhaust pipe and the turning portion becomes unclear, but it is not important "where the turning portion begins and ends", but what is important is that the direction of the exhaust guide path is changed (redirected) by the turning portion, which is a "member having a substantially U-shaped configuration". In addition, any of the exhaust pipes and turning portions constituting the first system may be configured as an assembly of multiple parts divided at any point. The method for assembling these multiple parts is not particularly limited as long as the required airtightness is achieved in the assembly as the exhaust pipe and / or turning portion, and examples of such methods include welding, band tightening, and crimping. Furthermore, the exhaust port formed at the rear end (downstream end) of the third exhaust pipe may be the rear end of the third exhaust pipe itself, or a baffle or muffler cutter may be attached to the rear end of the third exhaust pipe.

[0025] Fig. 1 is a schematic diagram showing an example of the configuration of the first system. The first system 101a shown in Fig. 1 is an exhaust system for a vehicle in which an upstream end 110 is connected to an internal combustion engine (not shown) mounted on a vehicle and an exhaust port 121 formed at a downstream end 120 is disposed at the rear end of the vehicle.

[0026] 1, an exhaust inlet 111 opens at an upstream end 110 of the first system 101a, and a flange portion 112 is formed around the end 111 for connecting and fixing the end 110 to an internal combustion engine (specifically, an exhaust port of the internal combustion engine or an exhaust manifold, a turbocharger, an exhaust purification device, or other equipment of the internal combustion engine). However, the means for connecting with the internal combustion engine is not limited to fastening with the flange portion described above, as long as it is possible to connect the internal combustion engine side and the first system in a hermetic manner, and a flexible joint (for example, a flexible pipe or a ball joint) can be used instead of the flange portion.

[0027] The first system 101a comprises, in order from upstream to downstream in the exhaust flow, a first exhaust pipe 130, a first turning section 140, a second exhaust pipe 150, a second turning section 160, a third exhaust pipe 170, and a main silencer 181.

[0028] The first exhaust pipe 130 is a member connected to the internal combustion engine and extending toward the rear of the vehicle. The first turning section 140 is a member connected to the downstream end of the first exhaust pipe 130 and turns toward the front of the vehicle. The second exhaust pipe 150 is a member connected to the downstream end of the first turning section 140 and extending toward the front of the vehicle. The second turning section 160 is a member connected to the downstream end of the second exhaust pipe 150 and turns toward the rear of the vehicle. The third exhaust pipe 170 is a member connected to the downstream end of the second turning section 160 and extending toward the rear of the vehicle. The main silencer 181 is interposed in the middle of the second exhaust pipe 150.

[0029] 1, the first exhaust pipe 130, the first turning portion 140, the second exhaust pipe 150, the second turning portion 160, and the third exhaust pipe 170 are each separate members, but are connected to adjacent members by welding to form an integral unit. However, as described above, each member may be configured as an assembly of multiple parts divided at any location, adjacent members may be formed integrally, and the method of connecting the separate members is not limited to welding, and the separate members may be connected to each other by, for example, band fastening, crimping, or other methods.

[0030] In the example shown in Fig. 1, the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 are depicted as being arranged parallel to one another on the same plane. However, when the first system is actually mounted on a vehicle, all of these three exhaust pipes do not have to be on the same plane. In addition, among these three exhaust pipes, there may be a set that is not parallel to one another, and there may be a set that has a different angle and position with respect to the longitudinal direction of the vehicle.

[0031] That is, in the first system, the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may be arranged so that at least one of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe is not on the same plane as the other pipe axes. In other words, the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may be arranged so that all of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe are not on the same plane. This further increases the degree of freedom in layout in the first system.

[0032] In the first system 101a shown in Fig. 1, the exhaust port 121 formed at the downstream end 120 is arranged to face the rear end of the vehicle. However, as in the first system 101b shown in Fig. 2, the exhaust port 121 can be arranged to face the side of the vehicle, for example, depending on the design requirements of the vehicle. Such a configuration also has the advantage that the third exhaust pipe 170 can be extended (tuning matter) in a long tail layout.

[0033] In the first system, an exhaust purification device (e.g., various catalytic converters and / or filter devices such as a diesel particulate filter (DPF) or a gasoline particulate filter (GPF)) and / or a sub-muffler (sub-muffler) may be installed in at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe. Furthermore, a flexible joint (e.g., a flexible pipe or a ball joint) may be installed, and any of such accessories may be installed in multiple locations.

[0034] For example, in a first system 101c shown in Fig. 3, a catalytic converter 190 serving as an exhaust purification device is provided in the first exhaust pipe 130. On the other hand, in a first system 101d shown in Fig. 4, a sub-muffler 182 is provided in the third exhaust pipe 170.

[0035] By adding an exhaust purification device and / or a sub silencer to the first system as described above, it is possible to flexibly respond to requirements for the vehicle, for example, regarding reduction of emissions and / or noise. Furthermore, since the first system provides a high degree of freedom in the position and / or orientation of each of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe, it also provides a high degree of freedom in the position and / or orientation of the above-mentioned accessories attached to these exhaust pipes. Therefore, it is possible to easily achieve effects such as prevention of heat damage and / or interference by ensuring the spacing between these accessories and surrounding members.

[0036] <effect> As described above, in the first system, the exhaust path from the internal combustion engine mounted on the vehicle to the exhaust port located at the rear end of the vehicle is configured to be substantially S-shaped or substantially Z-shaped. Therefore, each component (the first exhaust pipe to the third exhaust pipe and the first turning portion and the second turning portion) can be arranged three-dimensionally in the front-rear (longitudinal) direction, left-right (width) direction, and vertical (height) direction of the vehicle, allowing a high degree of freedom in layout. As a result, a long and large exhaust path can be arranged even in a small space (determined by the design specifications of the vehicle).

[0037] In the first system, the main silencer is disposed midway through the second exhaust pipe of the three exhaust pipes included in the exhaust path. Therefore, it is easy to place the main silencer in the middle of the exhaust path, and a long-tail layout can be easily realized. In other words, the first system can provide an exhaust system that allows high layout freedom even in a small space and allows a long-tail layout to be realized.

[0038] Furthermore, since the first system allows the main silencer to be easily positioned within the wheelbase of the vehicle, it can also contribute to improving driving stability compared to exhaust systems according to conventional technology in which the silencer 180 is mounted on the rear overhang 310 of the vehicle 300 as illustrated in FIG. 5.

[0039] Second Embodiment Hereinafter, a vehicle exhaust system according to a second embodiment of the present invention (hereinafter, may be referred to as a "second system") will be described with reference to the drawings.

[0040] As is well known to those skilled in the art, in the art, it is known to branch an exhaust path midway to multiplex it like a so-called "dual exhaust system" for the purpose of, for example, improving exhaust efficiency (reducing back pressure) and / or reducing exhaust noise, etc. In the exhaust system according to the present invention (the system of the present invention), it is also possible to branch an exhaust path midway to multiplex it.

[0041] <composition> That is, the second system is the first system described above, which is an exhaust system for a vehicle, comprising a plurality of exhaust units each consisting of a second exhaust pipe, a second turning portion, a main muffler and a third exhaust pipe, and the first turning portion has a branching portion that branches the exhaust flow path to each of the plurality of exhaust units.

[0042] As described above, in the first system, each component (the first to third exhaust pipes and the first and second turning portions) can be arranged three-dimensionally in the front-rear (longitudinal) direction, left-right (width) direction, and vertical (height) direction of the vehicle, allowing for a high degree of freedom in layout. As a result, a long exhaust path can be arranged even in a small space (determined by the design specifications of the vehicle).

[0043] The above-mentioned effects can be achieved in the second system as well, so that even in an exhaust system having multiple exhaust paths that would normally require a large space, each component can be arranged so that it can be stored in a small space.

[0044] Fig. 6 is a schematic diagram showing an example of the configuration of the second system. The second system 102a shown in Fig. 6 includes exhaust units, which are a set consisting of a second exhaust pipe 150, a second turning section 160, a third exhaust pipe 170, and a main silencer 181, arranged in the left and right (width) directions of the vehicle with the first exhaust pipe 130 sandwiched therebetween. The first turning section 140 is configured to branch the exhaust flow path into two in the left and right (width) directions of the vehicle at the branching section 141, and to guide the exhaust to the two exhaust units.

[0045] 6, the two exhaust units (each of the components constituting the two exhaust units) are depicted as being symmetrically arranged with the first exhaust pipe 130 in between, but the two exhaust units do not necessarily need to be symmetrically arranged and may be asymmetrically arranged. In addition, the number of exhaust units is not limited to two, and a configuration in which three or more exhaust units are provided as necessary is not excluded.

[0046] As described in the description of the first system, the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 do not all have to be on the same plane. Furthermore, there may be a set of these three exhaust pipes that are not parallel to each other, and there may be a set that has a different angle and position with respect to the longitudinal direction of the vehicle. That is, in each exhaust unit of the second system, the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may also be arranged so that at least one of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe is not on the same plane as the other pipe axes. This further increases the degree of freedom in layout in the second system.

[0047] 7, the exhaust port 121 can be arranged to face the side of the vehicle depending on the design requirements of the vehicle. This configuration also has the advantage that the third exhaust pipe 170 can be extended (tuning matter) in a long-tail layout.

[0048] Additionally, in the second system, at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may be provided with an exhaust purification device (e.g., various catalytic converters and / or filter devices such as a diesel particulate filter (DPF) or a gasoline particulate filter (GPF)) and / or a sub-muffler. Furthermore, a flexible joint (e.g., a flexible pipe or a ball joint) may be provided, and any of such accessories may be provided at multiple locations.

[0049] For example, in a second system 102c shown in Fig. 8, a catalytic converter 190 serving as an exhaust purification device is provided in the first exhaust pipe 130. On the other hand, in a second system 102d shown in Fig. 9, a sub-muffler 182 is provided in each of two third exhaust pipes 170 constituting the two exhaust units.

[0050] By adding an exhaust purification device and / or a secondary silencer to the multiple exhaust units of the second system as described above, it is possible to more flexibly respond to vehicle requirements, for example, regarding reduction of emissions and / or noise. Furthermore, since there is a high degree of freedom in the position and / or orientation of each of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe in the second system, there is also a high degree of freedom in the position and / or orientation of the above-mentioned accessories interposed in these exhaust pipes. Therefore, by ensuring the distance between these accessories and surrounding members, it is possible to easily achieve effects such as prevention of heat damage and / or interference.

[0051] As described above, the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 do not all have to be on the same plane, and there may be a set of these three exhaust pipes that are not parallel to each other, or a set that has a different angle and position with respect to the longitudinal direction of the vehicle. That is, in each exhaust unit of the second system, the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may also be arranged so that at least one of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe is not on the same plane as the other pipe axes. This further increases the degree of freedom in layout in the second system.

[0052] FIG. 10 is a schematic diagram showing an example of the configuration of the second system in which there are pairs of the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 that are not parallel to each other. In the second system 102e illustrated in FIG. 10, the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 are depicted as being arranged on the same plane. However, when the second system is actually mounted on a vehicle, there may be pairs of these three exhaust pipes that are not parallel to each other, and there may be pairs that have different angles and positions with respect to the front-rear direction of the vehicle. Also, in the second system 102e illustrated in FIG. 10, the two exhaust units (each of the members that constitute them) are depicted as being symmetrically arranged with the first exhaust pipe 130 in between, but the two exhaust units do not necessarily need to be symmetrically arranged and may be arranged asymmetrically.

[0053] Next, in Fig. 11, because the drawing is inevitably shown two-dimensionally, the third exhaust pipe 170 is drawn as passing inside the second exhaust pipe 150 in the left-right (width) direction of the vehicle, but in reality, the third exhaust pipe 170 is configured to pass above the second exhaust pipe 150 in the vertical (height) direction of the vehicle. Except for this point, the second system 102f illustrated in Fig. 11 has a similar configuration to the second system 102a illustrated in Fig. 6. Such a configuration is advantageous from the standpoint of lowering the center of gravity of the vehicle, for example, because the two main silencers 181, which have a large weight, can be mounted in a low position.

[0054] Even in the above-mentioned configuration, an exhaust purification device (e.g., various catalytic converters and / or filter devices such as a diesel particulate filter (DPF) or a gasoline particulate filter (GPF)) and / or a sub-muffler (sub-muffler) can be interposed in at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe. Furthermore, a flexible joint (e.g., a flexible pipe or a ball joint) may be interposed, and any of such accessories may be interposed in multiple locations.

[0055] For example, in a second system 102g illustrated in Fig. 12, a sub-muffler 182 is interposed midway through each of the two third exhaust pipes 170 constituting the two exhaust units. Except for this point, the second system 102g has a similar configuration to the second system 102f illustrated in Fig. 11. Although not shown, in the second system having multiplexed exhaust paths, in addition to or instead of the sub-muffler, an exhaust purification device and / or a flexible joint may be interposed in at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe.

[0056] <effect> In the second system, similarly to the first system, each component (the first exhaust pipe to the third exhaust pipe and the first turning portion and the second turning portion) can be arranged three-dimensionally in the front-rear (longitudinal), left-right (width) and vertical (height) directions of the vehicle, so that there is a high degree of freedom in layout. Therefore, according to the second system, although the exhaust system has multiple exhaust paths that originally require a large space, each component can be arranged so that it can be stored in a small space. As a result, an exhaust system having multiple exhaust paths can be constructed even in a small space (determined by the design specifications of the vehicle), thereby achieving improved exhaust efficiency (reduced back pressure) by expanding the exhaust flow path, and improving functions such as reducing emissions and / or noise by using multiple exhaust purification devices and / or mufflers.

[0057] Third Embodiment Hereinafter, a vehicle exhaust system according to a third embodiment of the present invention (hereinafter, may be referred to as a "third system") will be described with reference to the drawings.

[0058] As is well known to those skilled in the art, in this technical field, it is necessary to achieve both improved environmental performance, for example by reducing emissions and / or noise, and increased output of the internal combustion engine, for example by improving exhaust efficiency (reducing back pressure). On the other hand, in special situations, such as when driving on a circuit, more importance may be placed on increasing the output of the internal combustion engine.

[0059] <composition> Therefore, the third system is an exhaust system for a vehicle which is the above-mentioned first system or second system, and further comprises an outlet capable of discharging exhaust to the outside, and an opening / closing valve capable of increasing or decreasing the flow rate of exhaust passing through the outlet.

[0060] From the viewpoint of improving exhaust efficiency (reducing back pressure), it is preferable to provide the discharge port as far upstream as possible in the exhaust system. A specific example of the location where such a discharge port is formed is the first turning section. As the opening and closing valve, for example, a butterfly valve as disclosed in Patent Document 3 (JP Patent No. 7289628) may be installed inside the discharge port, and the valve opening degree may be controlled by a drive device such as an actuator.

[0061] Fig. 13 is a schematic diagram showing an example of the configuration of the third system. The third system 103a shown in Fig. 13 has a discharge port 201 capable of discharging exhaust gas to the outside formed near the front end of the first turning section 140, an opening / closing valve 202 capable of increasing / decreasing the flow rate of the exhaust gas passing through the discharge port 201 is installed inside the discharge port 201, and has an actuator 203 as a drive device for controlling the valve opening degree of the opening / closing valve 202, and has the same configuration as the first system 101a shown in Fig. 1, except that the third system 103a shown in Fig. 13 has a discharge port 201 capable of discharging exhaust gas to the outside formed near the front end of the first turning section 140, an opening / closing valve 202 capable of increasing / decreasing the flow rate of the exhaust gas passing through the discharge port 201 is installed inside the discharge port 201, and has an actuator 203 as a drive device for controlling the valve opening degree of the opening / closing valve 202.

[0062] According to the third system 103a having the above-mentioned configuration, during normal driving, the actuator 203 closes the on-off valve 202 to stop the exhaust gas from being discharged from the discharge port 201, and the third system 103a can exert its function of reducing emissions and / or noise. On the other hand, in a situation where an increase in the output of the internal combustion engine is more important, the actuator 203 fully opens the on-off valve 202 to discharge the exhaust gas from the discharge port 201, thereby reducing the back pressure and improving the exhaust efficiency.

[0063] The above-mentioned configuration can also be applied to the second system having multiple exhaust paths. Fig. 14 is a schematic diagram showing an example of the configuration of the third system having two exhaust units. The third system 103b shown in Fig. 14 has a discharge port 201 capable of discharging exhaust gas to the outside formed in the branching portion 141 of the first turning portion 140, an opening / closing valve 202 capable of increasing / decreasing the flow rate of the exhaust gas passing through the discharge port 201 is built in the discharge port 201, and has an actuator 203 as a driving device for controlling the valve opening degree of the opening / closing valve 202, and has the same configuration as the second system 102a shown in Fig. 6.

[0064] 13, in the third system 103b having the above configuration, the actuator 203 closes the on-off valve 202 to stop exhaust gas from being discharged from the discharge port 201 during normal driving, thereby allowing the third system 103a to exert its functions of reducing emissions and / or noise. On the other hand, in a situation where more importance is placed on increasing the output of the internal combustion engine, the actuator 203 fully opens the on-off valve 202 to discharge exhaust gas from the discharge port 201, thereby reducing back pressure and improving exhaust efficiency.

[0065] It is also possible to provide one discharge unit, which is a set consisting of a discharge port 201, an opening / closing valve 202, and an actuator 203, in each of the two exhaust units (a set consisting of the second exhaust pipe, the second turning portion, the main silencer, and the third exhaust pipe) included in the third system 103b. However, the above effect can be achieved by disposing only one discharge unit at the branching portion 141 of the first turning portion 140 as illustrated in Fig. 14. This advantage is also one of the merits brought about by the high degree of freedom in layout of the exhaust system for a vehicle according to the present invention (the system of the present invention).

[0066] Furthermore, similar to the first and second systems described above, the third system may have various variations, for example, in terms of the shape and arrangement of the exhaust pipe and the inclusion of accessories such as an exhaust purification device, a secondary silencer, and / or a flexible joint. For example, as in the third system 103c illustrated in FIG. 15, the exhaust port 121 may be arranged to face the side of the vehicle.

[0067] Also, in the third system, at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may be provided with an exhaust purification device, a secondary silencer, and / or a flexible joint, and any of such accessories may be provided at a plurality of locations. For example, in a third system 103d illustrated in Fig. 16, a catalytic converter 190 as an exhaust purification device is provided in the middle of the first exhaust pipe 130. On the other hand, in a third system 103e illustrated in Fig. 17, a secondary silencer 182 is provided in each of the two third exhaust pipes 170 constituting the two exhaust units.

[0068] Furthermore, in the third system as well, the first exhaust pipe 130, the second exhaust pipe 150, and the third exhaust pipe 170 do not all have to be on the same plane, and there may be a set of these three exhaust pipes that are not parallel to each other, and there may be a set that has a different angle and position with respect to the longitudinal direction of the vehicle. That is, in each exhaust unit provided in the third system as well, the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe may be arranged so that at least one of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe is not on the same plane as the other pipe axes. This further increases the degree of freedom in layout in the third system.

[0069] Additionally, the third system can also be configured so that the third exhaust pipe 170 passes above the second exhaust pipe 150 in the vertical (height) direction of the vehicle. In the third system 103f illustrated in Fig. 18, since the drawing is forced to be shown two-dimensionally, the third exhaust pipe 170 is depicted as passing inside the second exhaust pipe 150 in the left-right (width) direction of the vehicle, but in reality the third exhaust pipe 170 is configured to pass above the second exhaust pipe 150 in the vertical (height) direction of the vehicle.

[0070] In a third system 102g illustrated in Fig. 19, a sub-muffler 182 is provided midway through each of the two third exhaust pipes 170 constituting the two exhaust units. Except for this, the third system 103g has a similar configuration to the third system 103f illustrated in Fig. 18. Although not illustrated, in the third system having multiplexed exhaust paths, in addition to or instead of the sub-muffler, an exhaust purification device and / or a flexible joint may be provided in at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe.

[0071] The effects achieved by the various variations in the configuration of the third system as described above have already been described in the explanation of the first system and the second system having the corresponding configurations, so a detailed explanation will be omitted here.

[0072] <effect> In the third system, similarly to the first and second systems, each component (the first to third exhaust pipes and the first and second turning parts) can be arranged three-dimensionally in the front-rear (longitudinal), left-right (width) and vertical (height) directions of the vehicle, so that there is a high degree of freedom in layout. Therefore, according to the third system, although the exhaust system has multiple exhaust paths that originally require a large space, each component can be arranged so that it can be stored in a small space. As a result, an exhaust system having multiple exhaust paths can be constructed even in a small space, thereby achieving improved exhaust efficiency by expanding the exhaust flow path, and improving functions such as reducing emissions and / or noise by using multiple exhaust purification devices and / or mufflers.

[0073] In addition to the above, the third system further includes an outlet port capable of discharging exhaust gas to the outside, and an on-off valve capable of increasing or decreasing the flow rate of exhaust gas passing through the outlet port. Therefore, according to the third system, the on-off valve is closed during normal driving to stop exhaust gas from being discharged from the outlet port, and the third system can exert its function of reducing emissions and / or noise. On the other hand, in a situation where an increase in the output of the internal combustion engine is more important, the on-off valve is fully opened to discharge exhaust gas from the outlet port, thereby reducing back pressure and improving exhaust efficiency.

[0074] For the purpose of explaining the present invention, several embodiments having specific configurations have been described above, sometimes with reference to the attached drawings. However, the scope of the present invention should not be construed as being limited to these exemplary embodiments, and it goes without saying that appropriate modifications can be made within the scope of the claims and the matters described in the specification. [Explanation of symbols]

[0075] 101a, 101b, 101c, 101d, 102a, 102b, 102c, 102d, 102e, 102f, 102g, 103a, 103b, 103c, 103d, 103e, 103f, 103g...Vehicle exhaust system 110...Upstream end (front end) 111…Exhaust inlet 112…Flange section 120...Downstream end 121…Exhaust port 130…First exhaust pipe 140…First turning section 141...Branch 150…Second exhaust pipe 160…Second turning section 170…Third exhaust pipe 180...Silencer 181…Main silencer 182…Sub-silencer 190...Exhaust purification device (catalytic converter) 201...Discharge port 202...Opening and closing valve 203...Drive device (actuator) 300…Vehicle 310…Rear overhang

Claims

1. An exhaust system for a vehicle, the exhaust system having an upstream end connected to an internal combustion engine mounted on the vehicle and an exhaust port formed at a downstream end and disposed at a rear end of the vehicle, a first exhaust pipe connected to the internal combustion engine and extending to a rear of the vehicle; a first turning portion connected to a downstream end of the first exhaust pipe and turning toward the front of the vehicle; a second exhaust pipe connected to a downstream end of the first turning portion and extending forward of the vehicle; a second turning portion connected to a downstream end of the second exhaust pipe and turning toward the rear of the vehicle; a third exhaust pipe connected to a downstream end of the second turning portion and extending toward the rear of the vehicle; a main silencer disposed midway through the second exhaust pipe; Equipped with Vehicle exhaust system.

2. 2. A vehicle exhaust system as claimed in claim 1, At least one of the pipe axes of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe is not on the same plane as the other pipe axes. Vehicle exhaust system.

3. 3. A vehicle exhaust system according to claim 1 or 2, an exhaust purification device and / or a sub-muffler is provided in at least one of the group consisting of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe; Vehicle exhaust system.

4. 3. A vehicle exhaust system according to claim 1 or 2, a plurality of exhaust units each including the second exhaust pipe, the second turning portion, the third exhaust pipe, and the main muffler; The first turning portion includes a branching portion that branches an exhaust flow path to each of the plurality of exhaust units. Vehicle exhaust system.

5. 4. A vehicle exhaust system according to claim 3, a plurality of exhaust units each including the second exhaust pipe, the second turning portion, the third exhaust pipe, and the main muffler; The first turning portion includes a branching portion that branches an exhaust flow path to each of the plurality of exhaust units. Vehicle exhaust system.

6. 5. A vehicle exhaust system according to claim 4, An exhaust port capable of discharging exhaust air to the outside; an opening / closing valve capable of increasing or decreasing the flow rate of exhaust gas passing through the outlet; A drive device for controlling the opening degree of the on-off valve; A discharge unit consisting of a set of: is provided at the branching portion of the first turning portion, Vehicle exhaust system.

7. 6. A vehicle exhaust system according to claim 5, An exhaust port capable of discharging exhaust air to the outside; an opening / closing valve capable of increasing or decreasing the flow rate of exhaust gas passing through the outlet; A drive device for controlling the opening degree of the on-off valve; A discharge unit consisting of a set of: is provided at the branching portion of the first turning portion, Vehicle exhaust system.

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