Exhaust device for engine

[0067] Figure 1 to Figure 2 9 shows the first embodiment of the present invention.

[0068] figure 1 The exhaust system of the vehicle 1 according to the first embodiment is shown. When a given position of the exhaust system is defined as a reference, the side from the reference toward the engine 11 is referred to as the upstream side, and the side from the reference toward the exhaust outlet is referred to as the downstream side. The direction from the upstream side to the downstream side is called the exhaust forward AA, and the direction from the downstream side to the upstream side is called the exhaust reverse AB. The forward direction AA indicates the direction from the front side of the vehicle 1 to the rear side, and the reverse direction AB indicates the direction from the rear side of the vehicle 1 to the front side. It is assumed that the height direction AC of the vehicle coincides with the height direction, and the width direction AD of the vehicle 1 coincides with the horizontal direction.

[0069] The vehicle 1 is provided with an engine 11 and an exhaust device 2. The cylinder arrangement of the engine 11 is V-shaped. The exhaust device 2 changes the exhaust gas generated by the engine 11 to a desired state, and then guides the exhaust gas to the outside of the vehicle 1. The engine 11 is provided with a first cylinder group 12 and a second cylinder group 13. Each of the first cylinder group 12 and the second cylinder group 13 has a plurality of in-line cylinders.

[0070] The exhaust device 2 is provided with: left and right first catalytic converters 23; left and right second catalytic converters 24; sub-muffler 25; first muffler 4A; and second muffler 4B. The first catalytic converter 23 and the second catalytic converter 24 each purify harmful substances in exhaust gas. The sub muffler 25 muffles the exhaust gas downstream of the second catalytic converter 24. The first muffler 4A and the second muffler 4B each muffle the exhaust gas on the downstream side of the sub muffler 25.

[0071] The exhaust device 2 is further provided with: a first exhaust manifold 21; a second exhaust manifold 22; and an exhaust pipe 3. The first exhaust manifold 21 is connected to the exhaust port of the first cylinder group 12. The second exhaust manifold 22 is connected to the exhaust port of the second cylinder group 13. The exhaust pipe 3 is connected to each member described above. The first exhaust manifold 21, the second exhaust manifold 22 and the exhaust pipe 3 allow the flow of exhaust gas from the engine 11.

[0072] The first exhaust manifold 21 is provided with a main pipe 21A and a plurality of branch pipes 21B. The main pipe 21A is connected to the inlet of the first catalytic converter 23. The branch pipe 21B branches at the inlet of the main pipe 21A, and then each branch pipe 21B is connected to the corresponding exhaust port of the first cylinder group 12. The second exhaust manifold 22 is provided with a main pipe 22A and a plurality of branch pipes 22B. The main pipe 22A is connected to the inlet of the first catalytic converter 23. The branch pipe 22B branches on the inlet side of the main pipe 22A, and then each branch pipe 22B is connected to the exhaust port corresponding to the second cylinder group 13.

[0073] The exhaust pipe 3 is provided with: a first front pipe 31; a second front pipe 32; a first intermediate pipe 33; a second intermediate pipe 34; and a pair of tail pipes 35. The first front pipe 31 connects the outlet of the right first catalytic converter 23 to the inlet of the right second catalytic converter 24 on the downstream side of the first exhaust manifold 21. The second front pipe 32 connects the outlet of the left first catalytic converter 23 to the inlet of the left second catalytic converter 24 on the downstream side of the second exhaust manifold 22. The first intermediate pipe 33 connects the outlet of each second catalytic converter 24 to the inlet of the sub muffler 25. The second intermediate pipe 34 connects the outlet of the sub muffler 25 to the inlet of the first muffler 4A and the inlet of the second muffler 4B. Each tail pipe 35 is connected to the outlet corresponding to each of the first muffler 4A and the second muffler 4B.

[0074] The first intermediate pipe 33 is provided with: a main pipe 33A; and a first branch pipe 33B and a second branch pipe 33C branched on the inlet side of the main pipe 33A. The main pipe 33A is connected to the inlet of the sub muffler 25. The first branch pipe 33B and the second branch pipe 33C are each connected to the corresponding outlet of the second catalytic converter 24. The length from the branch point of the main pipe 33A to the entrance of the first branch pipe 33B is equal to the length from the branch point of the main pipe 33A to the entrance of the second branch pipe 33C. The main pipe 33A is provided at the center of the vehicle 1 in the width direction AD of the vehicle 1.

[0075] The second central pipe 34 is provided with: a main pipe 34A; and a first branch pipe 34B and a second branch pipe 34C branched on the outlet side of the main pipe 34A. The main pipe 34A is connected to the outlet of the sub muffler 25. The first branch pipe 34B is connected to the inlet of the first muffler 4A, and then the second branch pipe 34C is connected to the inlet of the second muffler 4B. The length from the branch point of the main pipe 34A to the outlet of the first branch pipe 34B is equal to the length from the branch point of the main pipe 34A to the outlet of the second branch pipe 34C. The main pipe 34A is provided in the center of the vehicle 1 in the width direction AD.

[0076] The exhaust gas from the first cylinder group 12 flows through in order: the first exhaust manifold 21; the first catalytic converter 23; the first front pipe 31; the second catalytic converter 24; the first intermediate pipe 33; Vice muffler 25.

[0077] Exhaust gas from the second cylinder group 13 flows sequentially through: the second exhaust manifold 22; the first catalytic converter 23; the second front pipe 32; the second catalytic converter 24; the first intermediate pipe 33; and Vice muffler 25. The exhaust gas from the sub muffler 25 flows through the first muffler 4A or the second muffler 4B via the second intermediate pipe 34 and is then discharged from the tail pipe 35 to the outside of the vehicle 1.

[0078] The first muffler 4A and the second muffler 4B are arranged in the lateral direction of the vehicle 1. In other words, the first muffler 4A and the second muffler 4B are arranged in parallel with respect to the front-rear direction of the vehicle 1. The first muffler 4A and the second muffler 4B are each a main muffler. The first muffler 4A and the second muffler 4B each have the same structure. The first muffler 4A and the second muffler 4B are of an inverted type, and each is connected to the exhaust pipe 3 in a different posture. The second muffler 4B is vertically inverted with respect to the first muffler 4A. The posture of the first muffler 4A is referred to as a reference posture, and the posture of the second muffler 4B is referred to as an inverted posture.

[0079] Figure 2 to Figure 6B The first muffler 4A is shown. Hereinafter, the first muffler 4A will be mainly described.

[0080] Such as image 3 As shown, the first muffler 4A is provided with: a muffler main body 41; an inflow pipe 7; an outflow pipe 8; and an inner pipe 9. The muffler main body 41 has a silencing chamber 5 for silencing the exhaust gas. The inflow pipe 7 allows exhaust gas to flow into the muffler chamber 5 from the second intermediate pipe 34. The outflow pipe 8 conveys the exhaust gas silencing in the anechoic chamber 5 to the tail pipe 35. The inner tube 9 is provided in the muffler main body 41.

[0081] In a state where the height direction AE of the first muffler 4A coincides with the height direction AC of the vehicle 1 and the width direction AF of the first muffler 4A coincides with the width direction AD of the vehicle 1, the first muffler 4A is connected to the second intermediate pipe 34 . Such as image 3 As shown, the longitudinal direction AG of the first muffler 4A is orthogonal to the height direction AE and the width direction AF.

[0082] The muffler main body 41 is provided with: a housing 42; a first outer plate 43; a second outer plate 44; a first spacer 45; and a second spacer 46. The flat cylindrical housing 42 has an anechoic chamber 5 therein. The housing 42 has a first opening on the upstream side and a second opening on the downstream side. The first outer plate 43 serving as the first outer wall closes the first mouth of the housing 42. The second outer plate 44 serving as the second outer wall closes the second mouth of the housing 42. The first partition 45 and the second partition 46 partition the anechoic chamber 5 into: a first anechoic chamber 51; a second anechoic chamber 52; and a third anechoic chamber 53.

[0083] The first outer plate 43 has a main body inlet portion 43A serving as a first plate opening. The main body inlet portion 43A supports the inflow pipe 7 serving as an inflow exhaust pipe. The inflow pipe 7 has an inflow inlet portion 7A located at the first end; and an inflow outlet portion 7B located at the second end. The inflow inlet portion 7A is joined to the main body inlet portion 43A.

[0084] The second outer plate 44 has a main body outlet portion 44A serving as a second plate opening. The main body outlet portion 44A supports the outflow pipe 8 serving as an outflow exhaust pipe. The outflow pipe 8 has: an outflow inlet portion 8A located at the first end; and an outflow outlet portion 8B located at the second end. The outflow outlet portion 8B is joined to the main body outlet portion 44A.

[0085] Figure 7 to Figure 9B The inside of the first muffler 4A is shown. Figure 7 A plan view of the first muffler 4A when the housing 42, the first outer plate 43, and the upper half of the second outer plate 44 have been removed is shown. Figure 8A A front view showing that the first muffler 4A has removed the first outer plate 43 therefrom; and Figure 8B It is a rear view showing that the first muffler 4A has removed the second outer plate 44 therefrom. Figure 9A Shows the first muffler 4A along Figure 5 A cross-sectional view taken at the line DA-DA, and Figure 9B Shows the first muffler 4A along Figure 5 A cross-sectional view taken from the line DB-DB.

[0086] Such as Figure 7 As shown, the housing 42, the first outer plate 43 and the second outer plate 44 define the anechoic chamber 5. The anechoic chamber 5 accommodates the first partition 45 and the second partition 46. The housing 42, the first outer plate 43 and the first partition 45 define a first anechoic chamber 51. The housing 42, the first partition 45 and the second partition 46 define a second anechoic chamber 52. The housing 42, the second partition 46 and the second outer plate 44 define a third anechoic chamber 53.

[0087] Such as Figure 9A As shown, the first spacer 45 used as the first inner wall has: a first support hole 45A; a second support hole 45B; a third support hole 45C; a fourth support hole 45D; a plurality of first through holes 45H; and two The second through hole 45I. The peripheral edge of the first support hole 45A supports the inflow pipe 7. The peripheries of the second support hole 45B, the third support hole 45C, and the fourth support hole 45D support the outflow pipe 8. Each of the first through hole 45H and the second through hole 45I connects the first anechoic chamber 51 and the second anechoic chamber 52. Within the range of ensuring the strength of the first spacer 45, the number and size of the first through holes 45H are increased to maximize the flow rate of exhaust gas flowing from the second anechoic chamber 52 to the first anechoic chamber 51. in Figure 9A Among them, the first support hole 45A is located at the lower left portion of the first spacer 45; the second support hole 45B is located at its lower right portion; the third support hole 45C is located at its upper left portion; and the fourth support hole 45D is located at its right middle portion. The position of the second support hole 45B is lower than the first support hole 45A, the third support hole 45C, and the fourth support hole 45D. One second through hole 45I is located between the first support hole 45A and the third support hole 45C, and the other second through hole 45I is located between the second support hole 45B and the fourth support hole 45D.

[0088] Such as Figure 9B As shown, the second spacer 46 used as the second inner wall has: a fifth support hole 46A; a sixth support hole 46B; a seventh support hole 46C; an eighth support hole 46D; a ninth support hole 46E; Tee 46H. The periphery of the fifth through hole 46A supports the inflow pipe 7. The peripheries of the sixth support hole 46B, the seventh support hole 46C, and the eighth support hole 46D support the outflow pipe 8. The peripheral edge of the ninth support hole 46E supports the inner tube 9. Each third through hole 46H connects the second anechoic chamber 52 with the third anechoic chamber 53. When the passage of the inner tube 9 is closed, a small amount of exhaust gas flows from the third anechoic chamber 53 to the second anechoic chamber 52 through the third through hole 46H. in Figure 9B In, the fifth support hole 46A is located at the lower left of the second spacer 46; the sixth support hole 46B is located at its lower right; the seventh support hole 46C is located at its upper left; the eighth support hole 46D is located at its right middle; and The support hole 46E is located in the upper middle part thereof. The position of the sixth support hole 46B is lower than that of the fifth support hole 46A and the seventh support hole 46C to the ninth support hole 46E.

[0089] Such as Figure 9A with Figure 9B As shown, the cross section of the housing 42 orthogonal to the front-rear direction (AA) of the vehicle 1 is formed in an elliptical shape. In other words, the cross section of the housing 42 extending in the width direction AF of the first muffler 4A is formed in an elliptical shape. The major axis LL of the ellipse extends in the width direction AD of the vehicle 1. The short axis LS extends in the height direction AC of the vehicle 1.

[0090] Such as Figure 9A with Figure 9B As shown, the housing 42 is divided in the circumferential direction into: a first body wall 42A; a second body wall 42B; a third body wall 42C; and a fourth body wall 42D. The first main body wall 42A, the second main body wall 42B, the third main body wall 42C, and the fourth main body wall 42D are the first peripheral wall portion, the second peripheral wall portion, the third peripheral wall portion, and the fourth peripheral wall portion of the housing 42, respectively. The first body wall 42A and the second body wall 42B are opposed to each other in the height direction AE of the first muffler 4A while the muffler chamber 5 is located between them. The third body wall 42C and the fourth body wall 42D each connect the first body wall 42A to the second body wall 42B. The third body wall 42C and the fourth body wall 42D are opposed to each other in the width direction AF of the first muffler 4A while the muffler chamber 5 is located between them. The first body wall 42A and the second body wall 42B are opposed to each other while the long axis LL is located between them. The third body wall 42C and the fourth body wall 42D are opposed to each other while the short axis LS is located between them.

[0091] Such as Figure 28A with Figure 28B As shown, the first main body wall 42A of the first muffler 4A is vertically lower than the second main body wall 42B of the first muffler 4A. In contrast, the first main body wall 42A of the second muffler 4B is higher than the second main body wall 42B of the second muffler 4B in the vertical direction. The bottom 41A of the first muffler 4A is the first main body wall 42A. The bottom 41A of the second muffler 4B is the second main body wall 42B.

[0092] Such as Figure 28A with Figure 28B As shown, the position of the third main body wall 42C of the first muffler 4A is close to the center in the width direction AD of the vehicle 1, and the position of the fourth main body wall 42D of the first muffler 4A is close to the side of the vehicle 1. The position of the third main body wall 42C of the second muffler 4B is close to the center in the width direction AD of the vehicle 1, and the position of the fourth main body wall 42D of the second muffler 4B is close to the side of the vehicle 1.

[0093] Such as Figure 10 to Figure 12B As shown, the inflow pipe 7 has an inflow and exhaust passage 7R extending from the inflow inlet portion 7A to the inflow outlet portion 7B. The inflow pipe 7 includes a first inflow pipe 71 and a second inflow pipe 72. The second inflow pipe 72 is connected in series to the outlet of the first inflow pipe 71. The first branch pipe 34B or the second branch pipe 34C is connected to the inflow inlet portion 7A. The inflow outlet portion 7B is provided in the third anechoic chamber 53.

[0094] The first end of the first inflow pipe 71 is referred to as a first inflow inlet portion 71A.

[0095] The second end of the first inflow pipe 71 is referred to as a first inflow outlet portion 71B.

[0096] The first end of the second inflow pipe 72 is referred to as a second inflow inlet portion 72A.

[0097] The second end of the second inflow pipe 72 is referred to as a second inflow outlet portion 72B.

[0098] The first inflow inlet portion 71A is the inflow inlet portion 7A, and the second inflow outlet portion 72B is the inflow outlet portion 7B.

[0099] As shown in FIG. 11, the first inflow pipe 71 has a first inflow passage 71R extending from the first inflow inlet portion 71A to the first inflow outlet portion 71B. The first inflow passage 71R extends in the longitudinal direction AG with respect to the muffler main body 41. The peripheral edge of the first support hole 45A of the first spacer 45 supports the first inflow outlet portion 71B. The plurality of fourth through holes 71H each connect the first inflow passage 71R with the first anechoic chamber 51.

[0100] Such as Figure 11A with Figure 11C As shown, the first inflow pipe 71 has a pair of fourth through holes 71H. The positions of the pair of fourth through holes 71H are opposed to each other in the height direction AE while the first inflow passage 71R is located between them. Such as Figure 9A As shown, the first inflow inlet portion 71A is located at the center of the muffler main body 41 in the height direction AE. The first inflow outlet portion 71B is located near the center of the muffler main body 41 in the height direction AE and its position is closer to the first main body wall 42A than the center. In other words, the first inflow pipe 71 is bent between the first inflow inlet portion 71A and the first inflow outlet portion 71B. The first inflow pipe 71 is located near the third main body wall 42C in the width direction AF of the muffler main body 41.

[0101] Such as Figure 12B As shown, the second inflow pipe 72 has a second inflow passage 72R for distributing exhaust gas from the second inflow inlet portion 72A to the second inflow outlet portion 72B. The second inflow pipe 72 linearly extends in the longitudinal direction AG with respect to the muffler main body 41. Such as Figure 7 As shown, the first support hole 45A of the first spacer 45 supports the second inflow inlet portion 72A. The fifth support hole 46A of the second spacer 46 supports the portion of the second inflow pipe 72 between the second inflow inlet portion 72A and the second inflow outlet portion 72B. The second inflow outlet portion 72B is provided in the third anechoic chamber 53. The second inflow pipe 72 has a plurality of fifth through holes 72H connecting the second inflow passage 72R and the second anechoic chamber 52. The fifth through holes 72H are distributed in the circumferential direction at the portion of the second inflow pipe 72 located in the second anechoic chamber 52. Such as Figure 9A As shown, the second inflow pipe 72 is located near the center of the muffler main body 41 in the height direction AE and is closer to the first main body wall 42A than the center. The second inflow pipe 72 is located near the third body wall 42C in the width direction AF.

[0102] Such as Picture 10 As shown in FIG. 13, the inner pipe 9 has an inner passage 9R that allows exhaust gas to flow from the inner inlet portion 9A to the inner outlet portion 9B. The inner tube 9 extends linearly in the longitudinal direction AG with respect to the muffler main body 41. Such as Figure 7 As shown, the inner entrance 9A is provided in the third anechoic chamber 53. The inner outlet portion 9B is provided in the second muffler 52. A valve device 91 for opening and closing the inner passage 9R is installed on the inner outlet portion 9B. The peripheral edge of the ninth support hole 46E of the second spacer 46 supports the inner outlet portion 9B. Such as Figure 9B As shown, the inner tube 9 is positioned near the center of the muffler main body 41 in the height direction AE near the second main body wall 42B, and positioned in the width direction AF near the center of the muffler main body 41 near the fourth main wall 42D.

[0103] Such as Figure 13A with Figure 13B As shown, the valve device 91 is provided with: a device main body 92; a valve body 93; and a return spring 94. The valve body 92 is mounted on the inner outlet portion 9B. The valve body 93 is provided in the valve body 92 and opens and closes the inner passage 9R. The return spring 94 urges the valve body 93 in the closing direction. When the engine 11 is stopped, the valve body 93 is maintained in a closed state. When the valve device 91 is closed, the inner passage 9R is also closed. When the pressure of the third anechoic chamber 53 is equal to or greater than the threshold value, the valve device 91 is maintained in the open state. When the valve device 91 is opened, the inner passage 9R is also opened. The valve device 91 is closed when the engine 11 is rotating at a low speed, and is opened when the engine 11 is rotating at a high speed.

[0104] Such as Figure 14 to Figure 2 As indicated by 0, the outflow pipe 8 has an outflow passage 8R that allows exhaust gas to flow from the outflow inlet portion 8A to the outflow outlet portion 8B. The outflow pipe 8 has a first outflow pipe 81; a second outflow pipe 82; a third outflow pipe 83; a fourth outflow pipe 84; and a fifth outflow pipe 85 connected in series. A high-frequency attenuation device 86 for attenuating high-frequency exhaust noise is provided around the fifth outflow pipe 85.

[0105] The first end of the first outflow pipe 81 is referred to as a first outflow inlet portion 81A.

[0106] The second end of the first outflow pipe 81 is referred to as a first outflow outlet portion 81B.

[0107] The first end of the second outflow pipe 82 is referred to as a second outflow inlet portion 82A.

[0108] The second end of the second outflow pipe 82 is referred to as a second outflow outlet portion 82B.

[0109] The first end of the third outflow pipe 83 is referred to as a third outflow inlet portion 83A.

[0110] The second end of the third outflow pipe 83 is referred to as a third outflow outlet portion 83B.

[0111] The first end of the fourth outflow pipe 84 is referred to as a fourth outflow inlet portion 84A.

[0112] The second end of the fourth outflow pipe 84 is referred to as a fourth outflow outlet portion 84B.

[0113] The first end of the fifth outflow pipe 85 is referred to as a fifth outflow inlet portion 85A.

[0114] The second end of the fifth outflow pipe 85 is referred to as a fifth outflow outlet portion 85B.

[0115] The outflow inlet portion 8A serving as the inlet of the outflow pipe is the same as the first outflow inlet portion 81A. The outflow outlet portion 8B serving as the outlet of the outflow pipe is the same as the fifth outflow outlet portion 85B.

[0116] Such as Figure 15A with Figure 15B As shown, the first outflow pipe 81 has a first outflow passage 81R that allows exhaust gas to flow from the first outflow inlet portion 81A to the first outflow outlet portion 81B. The first outflow pipe 81 extends linearly in the longitudinal direction AG with respect to the muffler main body 41. Such as Figure 7 As shown, the first inlet port 81A is provided in the first anechoic chamber 51. The outflow inlet portion 8A is a first opening that connects the first outflow passage 81R and the muffler chamber 5 in the vicinity of the first main body wall 42A. The second support hole 45B of the first spacer 45 supports the portion of the first outflow pipe 81 between the first outflow inlet portion 81A and the first outflow outlet portion 81B. The sixth support hole 46B of the second spacer 46 supports the first outflow outlet portion 81B. The first outflow pipe 81 is located near the first main body wall 42A in the height direction AE, and is positioned close to the fourth main body wall 42D near the center of the muffler main body 41 in the width direction AF.

[0117] Such as Figure 16A with Figure 16B As shown, the second outflow pipe 82 has a second outflow passage 82R that allows exhaust gas to flow from the second outflow inlet portion 82A to the second outflow outlet portion 82B. The second outflow pipe 82 is formed in a U shape. Such as Figure 9A with Figure 9B As shown, the exhaust gas flow of the second outflow pipe 82 changes from the forward direction to the reverse direction from the second outflow inlet portion 82A to the second outflow outlet portion 82B. The second inlet portion 82A is engaged with the second partition 46. The seventh support hole 46C of the second spacer 46 supports the second outflow outlet portion 82B. As the second outflow pipe 82 extends from the second outflow inlet portion 82A to the second outflow outlet portion 82B, the pipe extends from the vicinity of the first body wall 42A to the vicinity of the second body wall 42B in the height direction AE, and extends in the width direction. AF extends from the vicinity of the center of the anechoic chamber main body 41 to the vicinity of the third main body wall 42C.

[0118] Such as Figure 17A with Figure 17B As shown, the third outflow pipe 83 serving as the outflow intermediate portion has a third outflow passage 83R that allows exhaust gas to flow from the third outflow inlet portion 83A to the third outflow outlet portion 83B. The third outflow pipe 83 extends linearly in the longitudinal direction AG. The third outflow pipe 83 has three drainage holes 8C and a sixth through hole 8D. The drain hole 8C and the sixth through hole 8D are opposed to each other while the third outflow channel 83R is located between them. Each drain hole 8C is a second opening that connects the third outflow channel 83R with the muffler chamber 5 near the second body wall 42B. In other words, the outflow inlet portion 8A of the first muffler 4A is adjacent to the first main body wall 42A serving as the bottom of the first muffler 4A and the drain hole 8C of the first muffler 4A is adjacent to the second main body wall 42B serving as the top of the first muffler 4A . In contrast, the drain hole 8C of the second muffler 4B is adjacent to the second main body wall 42B serving as the bottom of the second muffler 4B and the outflow inlet portion 8A of the second muffler 4B is adjacent to the first main body wall 42A serving as the top of the second muffler 4B . The condensed water 54 of the second muffler 4B stays at the bottom 41A of the second muffler 4B, that is, stays on the second main body wall 42B; passes through the drain hole 8C; and then flows into the outflow pipe 8. The sixth through hole 8D connects the first inflow passage 71R and the second anechoic chamber 52. Such as Figure 9B As shown, the periphery of the seventh support hole 46C of the second spacer 46 supports the third inflow and inlet portion 83A. Such as Figure 9A As shown, the periphery of the third supporting hole 45C of the first spacer 45 supports the third outflow outlet portion 83B. The third outflow pipe 83 is located near the second body wall 42B in the height direction AE, and located near the third body wall 42C in the width direction AF.

[0119] Such as Figure 18A with Figure 18B As shown, the fourth outflow pipe 84 has a fourth outflow passage 84R that allows exhaust gas to flow from the fourth outflow inlet portion 84A to the fourth outflow outlet portion 84B. The fourth outflow pipe 84 is formed in a U shape. The exhaust flow of the fourth outflow pipe 84 changes from the reverse direction AB to the forward direction AA. Such as Figure 7 As shown, the fourth inflow port 84A is engaged with the first spacer 45 at the periphery of the third support hole 45C. The peripheral edge of the fourth support hole 45D of the first spacer 45 supports the fourth outflow outlet portion 84B. Such as Figure 9A with Figure 9B As shown, as the fourth outflow pipe 84 extends from the fourth outflow inlet portion 84A to the fourth outflow outlet portion 84B, the pipe extends along the height direction AE from the vicinity of the second body wall 42B to the center of the muffler body 41, and extends along The width direction AF extends from the vicinity of the third body wall 42C to the vicinity of the fourth body wall 42D.

[0120] Such as Figure 19A with Figure 19B As shown, the fifth outflow pipe 85 has a fifth outflow passage 85R that allows exhaust gas to flow from the fifth outflow inlet portion 85A to the fifth outflow outlet portion 85B. The fifth outflow pipe 85 extends linearly in the longitudinal direction AG. Such as Figure 9B As shown, the periphery of the fourth support hole 45D of the first spacer 45 supports the high-frequency attenuation device 86, thereby indirectly supporting the fifth inlet portion 85A. The fifth outflow outlet 85B is joined to the periphery of the main body outlet 44A. The fifth outflow pipe 85 is located in the center of the muffler main body 41 in the height direction AE, and is located in the vicinity of the fourth main body wall 42D in the width direction AF.

[0121] Such as Figure 20A with Figure 20B As shown, the high-frequency attenuation device 86 has a glass wool 86A and a cover 86B covering the glass wool 86A. The glass wool 86A surrounds the fifth outflow pipe 85 in the circumferential direction. High-frequency exhaust noise is attenuated by passing noise through the glass wool 86A. The glass wool 86A is located between the inner peripheral surface of the cover 86B and the outer peripheral surface of the fifth outflow pipe 85.

[0122] Figure 21 to Figure 23B The positions of the openings of the inflow pipe 7, the outflow pipe 8, the first outer plate 43, and the second outer plate 44 relative to the muffler main body 41 are respectively shown.

[0123] Such as Figure 21 with Figure 22 As shown, an imaginary plane orthogonal to the longitudinal direction AG of the muffler main body 41 is referred to as a first reference plane FF. In other words, the first reference surface FF extends along the width direction AF. The first housing projection view ZX used as the first body projection view shown in FIG. 23 can be obtained by projecting the housing 42 on the first reference plane FF. The projection direction of the first reference plane FF to the housing 42 is the longitudinal direction of the first muffler 4A. The first entrance projection map ZA1 can be obtained by projecting the inflow entrance 7A onto the first reference plane FF.

[0124] Such as Figure 21 with Figure 22 As shown, the cross section orthogonal to the center line CX of the housing 42 is referred to as a first reference body cross section FX. The first housing projection view ZX can also be obtained by projecting the shape of the housing 42 in the first reference main body section FX onto the first reference plane FF. The cross section orthogonal to the center line CAI of the inflow inlet portion 7A is referred to as a first reference inlet portion cross section FA1. The first entrance projection view ZA1 can also be obtained by projecting the shape of the inflow entrance 7A in the first reference entrance section FA1 on the first reference plane FF.

[0125] As shown in FIG. 23, the inflow inlet portion 7A is provided on the muffler main body 41 such that the center PA1 of the first inlet portion projection view ZA1 is located on the center line LX of the first housing projection view ZX in the height direction AE.

[0126] The main body inlet portion 43A is located at the center of the muffler main body 41 in the height direction AE. Can be obtained by projecting the main body entrance 43A onto the first reference plane FF Figure 23A The second entrance shown is a projection view of ZA2. Such as Figure 21 As shown, the imaginary cross-section orthogonal to the center line CA2 of the main body entrance portion 43A is referred to as the second reference entrance portion cross-section FA2. It can be obtained by projecting the shape of the main body entrance 43A in the second reference entrance section FA2 onto the first reference plane FF Figure 23A The second entrance shown is a projection view of ZA2.

[0127] Such as Figure 23A As shown, the first supporting entrance A is provided on the muffler main body 41 such that the center PA2 of the second entrance projection ZA2 is located on the center line LX of the first housing projection ZX along the height direction AE.

[0128] The outflow outlet portion 8B is located in the center of the muffler main body 41 in the height direction AE. Can be passed Figure 22 The shown outflow outlet portion 8B is projected onto the first reference plane FF to obtain Figure 23B The first exit portion shown is a projection ZB1. The cross section of the outflow outlet portion 8B orthogonal to the center line CB1 is referred to as a first reference outflow cross section FB1. It can also be obtained by projecting the shape of the outflow outlet portion 8B in the first reference outflow section FB1 onto the first reference plane FF Figure 23B The first outflow projection ZB1 is shown.

[0129] Such as Figure 23B As shown, the outflow outlet portion 8B is provided on the muffler main body 41 such that the center PB1 of the first outlet portion projection view ZB1 is located on the center line LX of the first housing projection view ZX along the height direction AE.

[0130] The main body outlet portion 44A is located in the center of the muffler main body 41 in the height direction AE. Can be passed Figure 22 The main body exit part 44A shown is projected onto the first reference plane FF to obtain Figure 23B The second exit part is shown as a projection ZB2. The cross section of the main body outlet portion 44A perpendicular to the center line CB2 is referred to as a second reference outlet portion cross section FB2. The second outlet portion projection view ZB2 can also be obtained by projecting the shape of the first support inlet portion A in the second reference outlet portion cross-section FB2 onto the first reference surface FF.

[0131] Such as Figure 23B As shown, the main body outlet portion 44A is provided on the muffler main body 41 such that the center PB2 of the second outlet portion projection view ZB2 is located on the center line LX of the first housing projection view ZX along the height direction AE.

[0132] Such as Figure 24A As shown, the third outflow pipe 83 is differently referred to as the first part 83C, the second part 83D, the third part 83E, and the fourth part 83F in the circumferential direction. The first portion 83C, the second portion 83D, the third portion 83E, and the fourth portion 83F are the first peripheral wall portion, the second peripheral wall portion, the third peripheral wall portion, and the fourth peripheral wall portion of the third outflow pipe 83, respectively. The first portion 83C and the second portion 83D are opposed to each other in the height direction AE while the third outflow passage 83R is located between them. The first part 83C of the first muffler 4A constitutes the bottom of the outflow pipe 8. The second part 83D of the second muffler 4B constitutes the bottom of the outflow pipe 8. The third part 83E and the fourth part 83F each connect the first part 83C to the second part 83D.

[0133] Three drainage holes 8C are located in the second part 83D. The sixth through hole 8D is located in the first portion 83C. The third portion 83E and the fourth portion 83F have no holes. In the third outflow passage 83R of the first muffler 4A, the condensed water 54 flows to the first portion 83C. In the third outflow passage 83R of the second muffler 4B, the condensed water 54 flows to the second portion 83D.

[0134] Figure 25 The exhaust gas flow in the first muffler 4A when the valve device 91 is closed is shown. Most of the exhaust gas in the inflow pipe 7 flows through the fifth through hole 72H of the second inflow pipe 72 and then flows into the second anechoic chamber 52. Part of the exhaust gas flowing into the inflow pipe 7 flows into the first anechoic chamber 51 through the fourth through hole 71H of the first inflow pipe 71 or into the third anechoic chamber 53 from the inflow outlet portion 7B. Most of the exhaust gas from the third anechoic chamber 53 stays in the third anechoic chamber 53 and part of the exhaust gas from the third anechoic chamber 53 flows into the second anechoic chamber 52 through each third through hole 46H. The exhaust gas from the second anechoic chamber 52 flows through the first through holes 45H and the second through holes 45I of the first partition 45 and then flows into the first anechoic chamber 51. The exhaust gas from the first anechoic chamber 51 flows into the outflow pipe 8 through the outflow inlet portion 8A, and flows through the first outflow pipe 81, the second outflow pipe 82, the third outflow pipe 83, the fourth outflow pipe 84, and the first outflow pipe in order. Five outflow pipes 85 are then discharged from the outflow outlet portion 8B to the outside of the muffler main body 41.

[0135] Such as Figure 25 As shown, when the valve device 91 is closed, the degree of expansion of the exhaust gas flowing into the muffler chamber 5 through the inflow pipe 7 is sufficiently larger than when the valve device 91 is opened. Therefore, the beneficial effect of reducing exhaust noise is improved. The third anechoic chamber 53 functions as a resonance chamber, thereby improving the beneficial effect of reducing exhaust noise having a specific frequency. A small amount of exhaust gas flows from the third anechoic chamber 53 to the second anechoic chamber 52 through each of the third through holes 46H. Therefore, for example, the degree of reduction in the noise pressure of the exhaust noise having a specific frequency is reduced compared to the case where the third through hole 46H is not present. Therefore, the degree of change in noise pressure associated with a specific bandwidth becomes lighter. Therefore, the difference between the noise pressure of a specific frequency and the noise pressure of the surrounding frequency is suppressed from becoming too large. This silencing effect reduces exhaust noise when the engine rotates at low speed. Therefore, the quietness during low-speed operation is improved.

[0136] Figure 26 The exhaust gas flow in the first muffler 4A when the valve device 91 is opened is shown. Most of the exhaust gas flowing into the inflow pipe 7 flows into the third anechoic chamber 53 through the inflow outlet portion 7B. Part of the exhaust gas from the inflow pipe 7 flows into the first anechoic chamber 51 through the fourth through hole 71H of the first inflow pipe 71 or into the second anechoic chamber 52 through the fifth through hole 72H of the second inflow pipe 72. Most of the exhaust gas from the third anechoic chamber 53 flows into the second anechoic chamber 52 through the inner pipe 9, and part of the exhaust gas from the third anechoic chamber 53 flows into the second anechoic chamber through each third through hole 46H 52. The exhaust gas from the second anechoic chamber 52 flows into the first anechoic chamber 51 through a set of first through holes 45H and each second through hole 45I of the first partition 45. Exhaust gas from the first muffler chamber 5 flows into the outflow pipe 8 through the outflow inlet portion 8A, sequentially flows through the first outflow pipe 81 to the fifth outflow pipe 85, and then is discharged from the outflow outlet portion 8B to the outside of the muffler main body 41 .

[0137] When the valve device 91 is opened, the resistance of the muffler chamber 5 to the exhaust gas flow is small compared to when the valve device 91 is closed. That is, the back pressure of the engine 11 decreases, and then the power of the engine at high-speed rotation increases.

[0138] Such as Figure 28A with Figure 28B As shown, the first muffler 4A in the reference posture is connected to the first branch pipe 34B. The first main body wall 42A of the first muffler 4A is located vertically below the second main body wall 42B. The first main body wall 42A of the first muffler 4A is opposed to the ground facing surface of the vehicle 1, and then the second main body wall 42B is opposed to the bottom of the vehicle 1. The ground facing surface of the vehicle 1 is located vertically below the bottom of the vehicle 1. The first muffler 4A and the second muffler 4B are located between the ground facing surface of the vehicle 1 and the bottom of the vehicle 1.

[0139] The second muffler 4B in the inverted posture is connected to the second branch pipe 34C. The second muffler 4B is vertically inverted with respect to the first muffler 4A, and the second main body wall 42B of the second muffler 4B is located vertically below the first main body wall 42A. The second main body wall 42B of the second muffler 4B is opposed to the ground facing surface of the vehicle 1, and the first main body wall 42A is opposed to the bottom of the vehicle 1.

[0140] The first catalytic converter 23 and the second catalytic converter 24 purify the exhaust gas, thereby generating water. When the exhaust gas that has flowed through the first catalytic converter 23 and the second catalytic converter 24 is cooled in the muffler main body 41, moisture in the exhaust gas is condensed, and then condensed water 54 is generated in the muffler main body 41. The condensed water 54 drops vertically downward due to gravity, and then stays at the bottom 41A of the corresponding one of the first muffler 4A and the second muffler 4B. If the condensed water 54 continues to stay on the bottom 41A, the housing 42, the first spacer 45 and the second spacer 46 will corrode, and thus the condensed water 54 needs to be discharged to the outside of the muffler main body 41.

[0141] In the respective one of the first muffler 4A and the second muffler 4B, the outflow inlet portion 8A opens near the first body wall 42A, and the drain hole 8C opens near the second body wall 42B.

[0142] In the first muffler 4A, the condensed water 54 in the third muffler chamber 53 flows through the gap between the second partition 46 and the housing 42 and then flows into the second muffler chamber 52. The condensed water 54 in the second anechoic chamber 52 flows into the first anechoic chamber 51 through the gap between the first partition 45 and the housing 42. Such as Figure 29A As shown, the condensed water 54 staying on the first main body wall 42A (bottom 41A) of the first muffler chamber 51 of the first muffler 4A flows into the outflow inlet 8A due to the exhaust flow, flows in the outflow pipe 8, and then It is discharged from the outflow outlet 8B to the outside of the muffler main body 41.

[0143] In the second muffler 4B, the condensed water 54 in the first muffler chamber 51 flows through the gap between the first partition 45 and the housing 42 and then flows into the second muffler chamber 52. The condensed water 54 in the third anechoic chamber 53 flows through the gap between the second partition 46 and the housing 42 and then flows into the second anechoic chamber 52. Such as Figure 29B As shown, the condensed water 54 staying on the second main body wall 42B (bottom 41A) of the second muffler chamber 52 of the second muffler 4B flows into the outflow pipe 8 through the drain hole 8C due to the exhaust flow, and flows into the outflow pipe 8 in the outflow pipe 8 The inside flows and is then discharged from the outflow outlet portion 8B to the outside of the muffler main body 41.

[0144] The method for manufacturing the exhaust device 2 has the following first to fifth steps.

[0145] Step 1: The constituent elements of the exhaust device 2 are prepared.

[0146] Step 2: Connect the exhaust manifolds 21, 22, the first catalytic converter 23, the first and second front pipes 31, 32, the second catalytic converter 24, the first intermediate pipe 33, the sub muffler 25 and the second intermediate The pipes 34 are connected to each other while correctly installing them on the vehicle 1 or the engine 11. These constituent elements may be installed on the vehicle 1 after a plurality of components have been assembled with each other. For example, the first intermediate pipe 33 is installed on the vehicle 1 after it has been assembled with the second catalytic converter 24 in advance.

[0147] Step 3: Mount the tail pipe 35 on the corresponding one of the first muffler 4A and the second muffler 4B.

[0148] Step 4: Connect the first muffler 4A in the reference posture to the first branch pipe 34B.

[0149] Step 5: Connect the second muffler 4B in the inverted posture to the second branch pipe 34C.

[0150] The exhaust device 2 may be incorporated in the vehicle 1 after assembly without being assembled on the vehicle.

[0151] The exhaust device 2 of the first embodiment has the following advantages.

[0152] (1) The exhaust device 2 is provided with: a first muffler 4A set in a reference posture; and a second muffler 4B set in an inverted posture. That is, the first muffler 4A and the second muffler 4B arranged in the lateral direction of the vehicle 1 each have the same structure, so that the cost of the exhaust device 2 can be reduced. In other words, the first muffler 4A and the second muffler 4B that are parallel to each other in the front-rear direction of the vehicle 1 each have the same muffler main body 41.

[0153] (2) The outflow pipe 8 has: an outflow inlet portion 8A opened near the first main body wall 42A; and a drain hole 8C opened near the second main body wall 42B. Therefore, the condensed water 54 staying at the bottom 41A of the first muffler 4A flows into the outflow pipe 8 through the outflow inlet portion 8A. The condensed water 54 staying in the bottom 41A of the second muffler 4B flows into the outflow pipe 8 through the drain hole 8C. Therefore, the condensed water 54 is discharged to the outside of the muffler main body 41 from both the first muffler 4A and the second muffler 4B. Therefore, the sharing of the first muffler 4A and the second muffler 4B can be compatible with the discharge characteristics of the condensed water 54 from the first muffler 4A and the second muffler 4B. The condensation water 54 is prevented from staying at the bottom of the muffler main body 41, and thus the outer shell 42, the first partition 45 and the second partition 46 are restricted from corrosion. Thus, the practicality of the first muffler 4A and the second muffler 4B is improved. The outflow pipe 8 is formed in a double U shape having two U shapes, so that the outflow inlet portion 8A opening near the first main body wall 42A and the drain hole 8C opening near the second main body wall 42B can be reliably provided.

[0154] (3) The outflow outlet 8B is located at the center of the muffler main body 41 in the height direction AE. Therefore, when viewed from the rear, that is, on the downstream side of the exhaust device 2, the layout of the outflow outlet portion 8B of the first muffler 4A and the outflow outlet portion 8B of the second muffler 4B is symmetrical. Therefore, the appearance of the vehicle 1 is improved. Therefore, the sharing of the first muffler 4A and the second muffler 4B may be compatible with the lateral symmetry of the rearward layout of the first muffler 4A and the second muffler 4B.

[0155] Assuming that a pair of conventional mufflers are provided and then each conventional muffler is connected to the exhaust pipe 3, the layout will not always be symmetrical. This embodiment improves this problem.

[0156] (4) The main body outlet portion 44A of the second outer plate 44 is located at the center in the height direction AE, and then the main body outlet portion 44A supports the outflow outlet portion 8B. Therefore, the first muffler 4A and the second muffler 4B are completely symmetrical when viewed from the rear, that is, viewed from the downstream side of the exhaust device 2. In other words, the rear shape of the first muffler 4A is completely symmetrical with the rear shape of the second muffler 4B about the center of the vehicle 1 in the width direction AF. Therefore, the appearance of the vehicle 1 is significantly improved.

[0157] (5) The inflow inlet portion 7A is located at the center of the muffler main body 41 in the height direction AE. Therefore, when viewed from the front, that is, viewed from the upstream side of the exhaust device 2, the layout of the inflow inlet 7A of the first muffler 4A and the inflow inlet 7A of the second muffler 4B is symmetrical. Therefore, the appearance of the vehicle 1 is improved. Therefore, the sharing of the first muffler 4A and the second muffler 4B can be compatible with the symmetry of the layout of the first muffler 4A and the second muffler 4B when viewed from the front.

[0158] (6) The first support inlet portion A of the first outer plate 43 is located at the center in the height direction AE. The inflow inlet portion 7A supports the first support inlet portion A. Therefore, when viewed from the front, that is, viewed from the upstream side of the exhaust device 2, the layout of the first muffler 4A and the second muffler 4B is completely symmetrical. In other words, the forward shape of the first muffler 4A and the forward shape of the second muffler 4B are completely symmetrical with respect to the center of the vehicle 1 in the width direction AF.

[0159] (7) The inflow inlet portion 7A is located at the center of the muffler main body 41 in the height direction AE. Therefore, defining the length of the first branch pipe 34B connected to the first muffler 4A to be equal to the length of the second branch pipe 34C connected to the second muffler 4B is compatible with arranging the main pipe 34A at the center of the vehicle 1 in the width direction AF. Therefore, the layout of the exhaust pipe 3, the first muffler 4A, and the second muffler 4B is improved.

[0160] Assuming that a conventional muffler is used, limiting the length of the first branch pipe 34B to be equal to the length of the second branch pipe 34C is not always compatible with arranging the main pipe 34A in the center of the vehicle 1 in the width direction AF. This embodiment improves this problem.

[0161] (8) The inflow inlet portion 7A is located at the center of the muffler main body 41 in the height direction AE. That is, in the first muffler 4A and the second muffler 4B, the position of the inflow inlet 7A is the same in the height direction AE. Therefore, the condensed water 54 hardly flows back from the muffler main body 41 to the upstream of any one of the first muffler 4A and the second muffler 4B in advance. Therefore, the sharing of the first muffler 4A and the second muffler 4B is compatible with restricting the backflow of the condensed water 54 from the first muffler 4A and the second muffler 4B.

[0162] Assume that in a state where the vehicle 1 is tilted and stopped, if the upstream side of the first muffler 4A is lower than the downstream side, if a large amount of condensed water 54 occurs in the first muffler 4A, the condensed water 54 can flow back from the inflow pipe 7 to Upstream side. In addition, it is assumed that when the inflow inlet portion 7A is not located at the center in the height direction AE, the condensed water 54 is highly likely to flow back to the upstream side of any one of the first muffler 4A and the second muffler 4B in advance. However, this embodiment prevents these problems.

[0163] (9) The third outflow pipe 83 has a drain hole 8C for allowing the condensed water 54 of the second muffler 4B to flow into the outflow pipe 8. Therefore, an additional pipe for allowing the condensate water 54 to flow into the outflow pipe 8 is unnecessary. In other words, the branch of the outflow pipe 8 is not required. Therefore, the structure of the first muffler 4A is simplified, so that the cost can be reduced. In addition, in the case where an additional pipe is allowed to be provided in the outflow pipe 8, the condensed water 54 of the second muffler 4B can be discharged from the additional pipe to the outside of the muffler main body 41.

[0164] (10) The outflow pipe 8 includes the first outflow pipe 81 to the fifth outflow pipe 85 connected in series. Therefore, even if the outflow pipe 8 has two U shapes, the direction of the exhaust gas flow changes slightly. Therefore, the resistance to the exhaust gas flow can be reduced. Therefore, the increase in the power of the engine 11 may be compatible with draining the condensate water 54 of the first muffler 4A and the second muffler 4B to the outside.

[0165] (11) The first muffler 4A and the second muffler 4B are each connected to the second intermediate pipe 34 in a state where the first muffler 4A and the second muffler 4B are inverted from each other in the vertical direction. The first muffler 4A and the second muffler 4B each have the same structure, so that the cost can be reduced.

[0166] The first embodiment described above can be modified as follows.

[0167] The sixth through hole 8D may be excluded from the first portion 83C of the third outflow pipe 83. That is, the third outflow pipe 83 only has the drainage hole 8C located in the second portion 83D.

[0168] The main body outlet portion 44A of the second outer plate 44 can support the portion of the outflow pipe 8 on the upstream side in addition to the outflow outlet portion 8B, and is not limited to supporting the outflow outlet portion 8B of the outflow pipe 8. In this case, the outflow pipe 8 is formed to extend linearly from the main body outlet portion 44A to the outflow outlet portion 8B. Therefore, the layout of the first muffler 4A and the second muffler 4B when viewed from behind the exhaust device 2 can be symmetrical, and the appearance of the vehicle 1 can be improved.

[0169] The first support inlet portion A of the first outer plate 43 can also support the portion of the inflow pipe 7 on the downstream side in addition to the inflow inlet portion 7A and is not limited to supporting the inflow inlet portion 7A of the inflow pipe 7. In this case, the inflow pipe 7 is formed to extend linearly from the first support inlet portion A to the inflow inlet portion 7A. Therefore, the layout of the first muffler 4A and the second muffler 4B when viewed from the front of the vehicle 1 may be symmetrical. In this case, limiting the length of the first branch pipe 34B connected to the first muffler 4A to be equal to the length of the second branch pipe 34C connected to the second muffler 4B may be the same as that of laying the main pipe 34A at the center of the vehicle 1 in the width direction. Content.

[0170] Figure 30 to 31B The second embodiment of the present invention is shown. The exhaust device of the second embodiment is partially different from the exhaust device of the first embodiment. The constituent elements common to the first embodiment are denoted by the same reference numerals.

[0171] Such as Figure 30 As shown, the third main body wall 42C of the housing 42 has a second main body inlet portion 42E, which serves as a main body opening that supports the inflow inlet portion 7A of the inflow pipe 7. The inflow pipe 7 is bent 90 degrees. Therefore, the first support inlet portion A has been omitted from the first outer plate 43.

[0172] Such as 3IA and Figure 31B The positions of the inlet pipe 7 and the opening of the housing 42 relative to the muffler main body 41 are shown.

[0173] Such as Figure 31A As shown, the inflow inlet portion 7A of the second embodiment is provided at the center of the muffler main body 41 in the height direction AE. The plane taken along the longitudinal direction AG and the height direction AE of the muffler main body 41 is referred to as a second reference plane FG. In other words, the second reference plane FG is orthogonal to the width direction AF. Can be obtained by projecting the housing 42 onto the second reference plane FG. Figure 31B The second housing projection view ZY of the second main body projection view shown. The projection direction of the housing 42 onto the second reference plane FG is the width direction AF of the muffler main body 41. Can be obtained by projecting the inflow inlet portion 7A onto the second reference plane FG Figure 31B The third entrance shown is a projection of ZA3. The cross section orthogonal to the center line CY of the housing 42 in the height direction AE is referred to as a second reference body cross section FY. The second housing projection view ZY can also be obtained by projecting the shape of the housing 42 in the second reference main body section FY onto the second reference plane FG. The cross section orthogonal to the center line CA3 of the inflow inlet portion 7A is referred to as a third reference inlet portion cross section FA3. The third entrance projection view ZA3 can also be obtained by projecting the shape of the inflow entrance 7A in the third reference entrance section FA3 onto the second reference plane FG.

[0174] Such as Figure 31B As shown, the inflow inlet portion 7A is provided on the muffler main body 41 such that the center PA3 of the third inlet portion projection view ZA3 is located on the center line LY of the second housing projection view ZY along the height direction AE.

[0175] Such as Figure 31A As shown, the second main body inlet 42E is located at the center of the muffler main body 41 in the height direction AE. The fourth entrance projection map ZA4 can be obtained by projecting the second main body entrance 42E onto the second reference plane FG. The cross section orthogonal to the center line CA4 of the second main body entrance portion 42E is referred to as a fourth reference entrance portion cross section FA4. The fourth entrance projection view ZA4 can also be obtained by projecting the shape of the second main body entrance 42E in the fourth reference entrance section FA4 onto the second reference plane FG.

[0176] Such as Figure 31B As shown, the second main body entrance 42E is provided on the muffler main body 41 such that the center PA4 of the fourth entrance projection ZA4 is located on the center line LY of the second housing projection ZY along the height direction AE.

[0177] The second embodiment has advantages similar to the advantages (1) to (10) of the first embodiment.

[0178] Figure 32 to Figure 3 3B shows the third embodiment of the present invention. Such as Figure 32 As shown, the fourth main body wall 42D of the housing 42 has a second main body outlet portion 42F, which serves as a main body opening for supporting the outflow outlet portion 8B of the outflow tube 8. The fifth outflow pipe 85 is bent 90 degrees. The main body outlet portion 44A is omitted from the second outer plate 44.

[0179] Such as Figure 33A As shown, the outflow outlet portion 8B is located at the center of the muffler main body 41 in the height direction AE. The plane taken along the longitudinal direction AG of the muffler main body 41 is referred to as a second reference plane FG. The second housing projection view ZY can be obtained by projecting the housing 42 onto the second reference plane FG. The third outlet portion projection diagram ZB3 can be obtained by projecting the outflow outlet portion 8B onto the second reference plane FG. The cross section orthogonal to the center line CB3 of the outflow outlet portion 8B is referred to as a third reference outlet portion cross section FB3. The third outlet portion projection view ZB3 can also be obtained by projecting the shape of the outflow outlet portion 8B in the third reference outlet portion cross section FB3 onto the second reference surface FG.

[0180] As shown in FIG. 33B, the outflow outlet portion 8B is provided on the muffler main body 41 such that the center PB3 of the third outlet portion projection view ZB3 is located on the center line LY of the second housing projection view ZY in the height direction AE.

[0181] Such as Figure 33A As shown, the second main body outlet portion 42F is located at the center of the muffler main body 41 in the height direction AE. The fourth exit portion projection map ZB4 can be obtained by projecting the second main body exit portion 42F onto the second reference plane FG. The cross section orthogonal to the center line CB4 of the second main body outlet portion 42F is referred to as a fourth reference outlet portion cross section FB4. The fourth exit portion projection view ZB4 can also be obtained by projecting the shape of the second main body exit portion 42F on the fourth reference exit portion cross-section FB4 onto the second reference plane FG.

[0182] As shown in FIG. 33B, the second main body outlet portion 42F is provided on the muffler main body 41 such that the center PB4 of the fourth outlet portion projection view ZB4 is located on the center line LY of the second housing projection view ZY along the height direction AE.

[0183] The third embodiment has advantages similar to the advantages (1) to (10) of the first embodiment.

[0184] Figure 34A to Figure 34C The fourth embodiment of the present invention is shown.

[0185] In the third outflow pipe 83, the third portion 83E and the fourth portion 83F each have two drainage holes 8C. In other words, the third portion 83E and the fourth portion 83F in which the third portion 83E and the fourth portion 83F between which the third outflow channel 83R is located are opposed to each other in the width direction AF respectively have the drainage holes 8C. No holes are provided in the first portion 83C and the second portion 83D.

[0186] The fourth embodiment has the advantages (1) to (10) of the first embodiment and the following advantages.

[0187] (12) In the third outflow pipe 83, the drain hole 8C exists only in the third part 83E and the fourth part 83F. Therefore, the condensed water 54 that has flowed into the outflow pipe 8 through the outflow inlet portion 8A in the first muffler 4A is restricted from flowing to the outside of the outflow pipe 8 before reaching the outflow outlet portion 8B.

[0188] The fourth embodiment can be changed as follows.

[0189] The drainage hole 8C of the third outflow pipe 83 may exist in any one of the third portion 83E and the fourth portion 83F and is not limited to the configuration in which the drainage hole exists in both portions. A drain hole 8C may be provided in any one of the second part 83D to the fourth part 83F.

[0190] Figure 35 The fifth embodiment of the present invention is shown.

[0191] The first spacer 45 of the fifth embodiment has a seventh through hole 45J instead of the plurality of first through holes 45H. In order to ensure the flow rate of the exhaust gas from the second anechoic chamber 52 to the first anechoic chamber 51, the size of the seventh through hole 45J is maximized under the premise of ensuring the strength of the first spacer 45.

[0192] The fifth embodiment has advantages similar to the advantages (1) to (10) of the first embodiment.

[0193] The above embodiment can be modified as follows.

[0194] The drain hole 8C may be provided in the second outflow pipe 82 or the fourth outflow pipe 84 and is not limited to the configuration in which the hole is provided in the third outflow pipe 83. For example, the drain hole 8C is provided at a portion of the second outflow pipe 82 adjacent to the second main body wall 42B, that is, at the second wall facing portion. The second wall facing portion corresponds to the second outflow outlet portion 82B and its surroundings. In addition, the drain hole 8C is provided at a portion of the fourth outflow pipe 84 adjacent to the second body wall 42B, that is, at the fourth wall facing portion. The fourth wall facing portion corresponds to the fourth outflow inlet portion 84A and its surroundings.

[0195] The drain hole 8C can be excluded from the third outflow pipe 83. In this case, the opening of the branch pipe branching at a part of the outflow pipe 8 is provided in the vicinity of the second main body wall 42B. The condensed water 54 of the second muffler 4B can be discharged to the outside via the branch pipe.

[0196] A second drain hole similar to the drain hole 8C may be provided in the outflow pipe 8 and is not limited to a configuration in which the condensate 54 of the first muffler 4A is sent into the outflow pipe 8 from the outflow inlet portion 8A. The second drain hole is provided near the first main body wall 42A.

[0197] The inflow pipe 7 may be formed not by the first inflow pipe 71 and the second inflow pipe 72 but by a single pipe, or may be formed by three or more pipes.

[0198] The outflow pipe 8 may not be formed by the first outflow pipe 81 to the fifth outflow pipe 85 but by one to four pipes, or six or more pipes.

[0199]The main pipe 33A of the first intermediate pipe 33 does not need to be positioned at the center of the vehicle 1 in the width direction AD but may be away from the center.

[0200] The length of the first branch pipe 33B of the first intermediate pipe 33 need not be equal to the length of the second branch pipe 33C but may be different.

[0201] The main pipe 34A of the second intermediate pipe 34 does not need to be positioned at the center of the vehicle 1 in the width direction AD but may be away from the center.

[0202] The length of the first branch pipe 34B of the second intermediate pipe 34 need not be equal to the length of the second branch pipe 34C but may be different.

[0203] The second embodiment can be combined with the third embodiment.

[0204] Not only one muffler but also a plurality of mufflers may be connected to the first branch pipe 34B of the second intermediate pipe 34. As many mufflers as those connected to the first branch pipe 34B are connected to the second branch pipe 34C.

[0205] In addition to the first branch pipe 34B and the second branch pipe 34C, the second intermediate pipe 34 may be provided with a third branch pipe and a fourth branch pipe. The mufflers connected to the third branch pipe and the fourth branch pipe are also inverted from each other in the vertical direction.

[0206] In the illustrated embodiment, the exhaust device 2 is provided with a pair of a first muffler 4A and a second muffler 4B. However, the exhaust device 2 may be provided with two or more pairs of the first muffler 4A and the second muffler 4B. For example, the exhaust device 2 may be provided with a first pair on the upstream side and a second pair on the downstream side. The first pair is provided with a first muffler 4A and a second muffler 4B, and the second pair is also provided with a first muffler 4A and a second muffler 4B.

[0207] The cylinder arrangement of the engine 11 is not limited to the V-shape. The exhaust device 2 can be modified according to the cylinder arrangement as required.