MUFFLER AND ENGINE EXHAUST APPARATUS

• US 20100126799A1
• Filed: 08/09/2007
• Published: 05/27/2010
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Matsueda, Koji, Tsuji, Tomoyuki
• Granted Patent: US 7,918,311 B2
• Time in Patent Office: Days
• US Class Current: 181/271
• CPC Class Codes: F01N 1/083 using transversal baffles defining a tortuous path for the gases or successively throttling gas flow
• CPC Class Codes: F01N 1/084 the gases flowing through the silencer two or more times longitudinally in opposite directions, e.g. using parallel or concentric tubes
• CPC Class Codes: F01N 1/089 using two or more expansion chambers in series F01N1/083, F01N1/084, F01N1/086 take precedence
• CPC Class Codes: F01N 1/16 by using movable parts
• CPC Class Codes: F01N 1/163 by means of valves
• CPC Class Codes: F01N 2290/10 actuated by pressure of exhaust gases, e.g. exhaust pulses
• CPC Class Codes: F01N 2470/02 Tubes being perforated
• CPC Class Codes: F01N 2470/04 characterised by shape, disposition or dimensions of apertures
• CPC Class Codes: F01N 2490/02 Two or more expansion chambers in series connected by means of tubes
• CPC Class Codes: F01N 2490/06 the gases flowing longitudinally from inlet to outlet in opposite directions
• CPC Class Codes: F01N 2490/08 Two or more expansion chambers in series separated by apertured walls only

Abstract

A muffling chamber (5) is located between a first main body wall (42A) and a second main body wall (42B) with respect to a height direction (AE). An outflow pipe (8) has: a first opening (8A) that connects an outflow passage (8R) with a muffling chamber (5) in the vicinity of a first main body wall (42A); and a second opening (8C) that connects the outflow passage (8R) with the muffling chamber (5) in the vicinity of a second main body wall (42B). The liquid staying on the first main body wall (42A) of a first muffler (4A) flows into the outflow passage (8R) through the first opening (8A). The liquid staying on a second main body wall (42B) of a second muffler (4B) flows into the outflow passage (8R) through a second opening (8C). Therefore, the symmetry of the first muffler (4A) and the second muffler (4B) is compatible with anti-corrosion.

Claims

1. An exhaust apparatus (2) for an engine (11) of a vehicle (1), the exhaust apparatus comprising:

an exhaust pipe (3) through which exhaust of the engine (11) flows; and

a first muffler (4A) and a second muffler (4B) arranged in a transverse direction of the vehicle (1), the first muffler (4A) and the second muffler (4B) being connected to the exhaust pipe (3) while being vertically inverted with respect to each other,

wherein the first muffler (4A) and the second muffler (4B) each includes;

a muffler main body (41) having a muffling chamber (5) for muffling the exhaust;

an inflow pipe (7) for allowing exhaust of the exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside, the outflow pipe (8) having an outflow outlet (8B) from which exhaust outflows, the outflow outlet (8B) being positioned at a center (LL) in a height direction (AE) of the muffler main body (41).

2. The exhaust apparatus (2) according to claim 1, wherein the muffler main body (41) has a main body outlet (44A) for supporting the outflow outlet (8B), and

wherein the main body outlet (44A) is positioned at a center (LL) of a height direction (AE) of the muffler main body (41).

3. The exhaust apparatus (2) according to claim 1, wherein the muffler main body (41) has a main body outlet (44A) for supporting the outflow pipe (8),

wherein the outflow outlet (8B) extends through the main body outlet (44A), and then, is disposed at the outside of the muffler main body (41),

wherein a portion of the outflow pipe (8) located at the outside of the muffler main body (41) extends straight, and

wherein the main body outlet (44A) is located at a center (LL) of a height direction (AE) of the muffler main body (41).

7. The exhaust apparatus (2) according to any one of claims 1 to 6, wherein the muffler main body (41) includes:

a cylindrical shell body (42) defining the muffling chamber (5), the shell body (42) having a first mouth and a second mouth that is opposite to the first mouth, the shell body (42) defining a first reference plane (FF) that is perpendicular to a longitudinal direction (AG) of the cylinder;

a first exterior wall (43) closing the first mouth; and

a second exterior wall (44) closing the second mouth, the second exterior wall (44) having a main body outlet (44A) for supporting the outflow pipe (8),

wherein the outflow pipe (8) having an outflow outlet (8B) from which exhaust outflows,

wherein a first shell body projection view (ZX) is obtained by projecting the shell body (42) onto the first reference plane (FF),

wherein a first outlet projection view (ZB1) is obtained by projecting the outflow outlet (8B) onto the first reference plane (FF),

wherein a second outlet projection view (ZB2) is obtained by projecting the main body outlet (44A) onto the first reference plane (FF), and

wherein at least one of a center (PB1) of the first outlet projection view (ZB1) and a center (PB2) of the second outlet projection view (ZB2) is located at a center (LX) in a height direction (AE) of the first shell body projection view (ZX).

8. The exhaust apparatus (2) according to any one of claims 1 to 6, wherein the muffler main body (41) includes:

a shell body (42) having the muffling chamber (5) therein, the shell body (42) being formed in a cylindrical shape and having a first mouth and a second mouth that is opposite to the first mouth, a side part of the shell body (42) having a main body outlet (42F) for supporting the outflow pipe (8), the shell body (42) defining a second reference plane (FG) that is parallel to a longitudinal direction (AG) and a height direction (AE) of the cylinder,

wherein the outflow pipe (8) has an outflow outlet (8B) from which exhaust outflows,

wherein a second shell body projection view (ZY) is obtained by projecting the shell body (42) onto the second reference plane (FG),

wherein a third outlet projection view (ZB3) is obtained by projecting the outflow outlet (8B) onto the second reference plane (FG),

wherein a fourth outlet projection view (ZB4) is obtained by projecting the main body outlet (42F) onto the second reference plane (FG), and

wherein at least one of a center (PB3) of the third outlet projection view (ZB3) and a center (PB4) of the fourth outlet projection view (ZB4) is located at a center (LY) in a height direction (AE) of the second shell body projection view (ZY).

9. The exhaust apparatus (2) according to any one of claims 1 to 8, wherein the inflow pipe (7) has an inflow inlet (7A) into which exhaust flows, and

wherein the inflow inlet (7A) is located at a center (LL) in a height direction (AE) of the muffler main body (41).

10. The exhaust apparatus (2) according to claim 9, wherein the muffler main body (41) has a main body inlet (43A) for supporting the inflow pipe (7), and

wherein the main body inlet (43A) is located at a center (LL) of a height direction (AE) of the muffler main body (41).

11. The exhaust apparatus (2) according to claim 9, wherein the muffler main body (41) has a main body inlet (43A) for supporting the inflow pipe (7),

wherein the inflow inlet (7A) extends through the main body inlet (43A) and exists at the outside of the muffler main body (41),

wherein a portion of the inflow pipe (7) located at the outside of the muffler main body (41) extends straight, and

wherein the main body inlet (43A) is located at a center (LL) in a height direction (AE) of the muffler main body (41).

12. The exhaust apparatus (2) according to any one of claims 1 to 8, wherein the muffler main body (41) has a main body inlet (43A) for supporting the inflow pipe (7), and

wherein the main body inlet (43A) is located at a center (LL) in a height direction (AE) of the muffler main body (41).

13. The exhaust apparatus (2) according to claim 12, wherein the inflow pipe (7) has an inflow inlet (7A) into which exhaust flows, and

wherein the main body inlet (43A) supports the inflow inlet (7A).

14. The exhaust apparatus (2) according to claim 12, wherein the inflow pipe (7) has an inflow inlet (7A) into which exhaust flows,

wherein the inflow inlet (7A) extends through the main body inlet (43A), and exists at the outside of the muffler main body (41), and

wherein a portion of the inflow pipe (7) located at the outside of the muffler main body (41) extends straight.

15. The exhaust apparatus (2) according to any one of claims 9 to 14, wherein the muffler main body (41) includes:

a cylindrical shell body (42) defining the muffling chamber (5), the shell body (42) having a first mouth and a second mouth that is opposite to the first mouth, the shell body (42) defining a first reference plane (FF) that is perpendicular to a longitudinal direction (AG) of the cylinder;

a first exterior wall (43) closing the first mouth, the first exterior wall (43) having a main body inlet (43A) for supporting the inflow pipe (7); and

a second exterior wall (44) closing the second mouth,

wherein the inflow pipe (7) has an inflow inlet (7A) into which exhaust flows,

wherein a first shell body projection view (ZX) is obtained by projecting the first exterior wall (43) onto the first reference plane (FF),

wherein a first inlet projection view (ZA1) is obtained by projecting the inflow inlet (7A) onto the first reference plane (FF),

wherein a second inlet projection view (ZA2) is obtained by projecting the main body inlet (43A) onto the first reference plane (FF), and

wherein at least one of a center (PA1) of the first inlet projection view (ZA1) and a center (PA2) of the second inlet projection view (ZA2) is located at a center (LX) in a height direction (AE) of the first shell body projection (ZX).

16. The exhaust apparatus (2) according to any one of claims 9 to 14, wherein the muffler main body (41) includes:

a shell body (42) having the muffling chamber (5) therein, the shell body (42) being formed in a cylindrical shape and having a first mouth and a second mouth that is opposite to the first mouth, a side part of the shell body (42) having a main body inlet (42E) for supporting the inflow pipe (7), the shell body (42) defining a second reference plane (FG) that is parallel to a longitudinal direction (AG) and a height direction (AE) of the cylinder,

wherein the inflow pipe (7) has an inflow inlet (7A) into which exhaust flows,

wherein a second shell body projection view (ZY) is obtained by projecting the shell body (42) onto the second reference plane (FG),

wherein a third inlet projection view (ZA3) is obtained by projecting the inflow inlet (7A) onto the second reference plane (FG),

wherein a fourth inlet projection view (ZA4) is obtained by projecting the main body inlet (42E) onto the second reference plane (FG), and

wherein at least one of a center (PA3) of the third inlet projection view (ZA3) and a center (PA4) of the fourth inlet projection view (ZA4) is located at a center (LY) in a height direction (AE) of the second shell body projection view (ZY).

17. The exhaust apparatus (2) according to any one of claims 1 to 16, wherein the muffler main body (41) has a first main body wall (42A) and a second main body wall (42B) that are opposite to each other in a height direction (AE), the muffling chamber (5) existing between the first main body wall (42A) and the second main body wall (42B), and

wherein the outflow pipe (8) has:

a first opening (8A) that connects a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the first main body wall (42A); and

a second opening (8C) that connects a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the second main body wall (42B).

19. The exhaust apparatus (2) according to claim 17 or claim 18, wherein the first main body wall (42A) of the first muffler (4A) exists vertically downwardly of the second main body wall (42B) of the first muffler (4A), and

wherein the first main body wall (42A) of the second muffler (4B) is located vertically upwardly of the second main body wall (42B) of the second muffler (4B).

20. The exhaust apparatus (2) according to any one of claims 17 to 19, wherein the outflow pipe (8) has an outflow intermediate part (83) that is adjacent to the second main body wall (42B), and

wherein the outflow intermediate part (83) has a second opening (8C) that connects a passage (83R) of the outflow pipe (8) with the muffling chamber (5).

21. The exhaust apparatus (2) according to claim 20, wherein the outflow intermediate part (83) of the first muffler (4A) includes:

a first portion (83C) through which a liquid having flowed into the outflow pipe (8) through the first opening (8A) flows;

a second portion (83D) that is opposite to the first portion (83C); and

a third portion (83E) and a fourth portion (83F), each of which connects the first portion (83C) to the second portion (83D),

wherein at least one of the third portion (83E) and the fourth portion (83F) has the second opening (8C).

22. The exhaust apparatus (2) according to claim 20, wherein the outflow intermediate part (83) of the first muffler (4A) includes:

a first portion (83C) through which a liquid having flowed into the outflow pipe (8) through the first opening (8A) flows;

a second portion (83D) that is opposite to the first portion (83C);

a third portion (83E) and a fourth portion (83F), each of which connects the first portion (83C) to the second portion (83D),

wherein at least one of the second portion (83D), the third portion (83E), and the fourth portion (83F) has the second opening (8C).

23. The exhaust apparatus (2) according to claim 20, wherein the outflow intermediate part (83) of the first muffler (4A) includes:

a first portion (83C) through which a liquid having flowed into the outflow pipe (8) through the first opening (8A) flows; and

a second portion (83D) that is opposite to the first portion (83C),

wherein the first portion (83C) has a through hole (8D) that connects a passage (83R) of the outflow intermediate part (83) with the muffling chamber (5), and

wherein only the second portion (83D) has the second opening (8C).

24. The exhaust apparatus (2) according to claim 20, wherein the outflow intermediate part (83) of the first muffler (4A) includes:

a first portion (83C) through which a liquid having flowed into the outflow pipe (8) through the first opening (8A) flows; and

a second portion (83D) that is opposite to the first portion (83C),

wherein only the second portion (83D) has the second opening (8C).

25. The exhaust apparatus (2) according to any one of claims 17 to 24, wherein the outflow pipe (8) has an outflow inlet (8A) into which exhaust flows, and

wherein the outflow inlet (8A) is the first opening (8A).

26. The exhaust apparatus (2) according to any one of claims 17 to 25, wherein the muffler main body (41) has a third main body wall (42C) and a fourth main body wall (42D), each of which connects the first main body wall (42A) to the second main body wall (42B),

wherein a forward direction (AA) oriented from an upstream to a downstream and a reverse direction (AB) opposite to the forward direction (AA) are defined with respect to a longitudinal direction (AG) of the muffler main body (41), wherein a width direction (AF) is perpendicular to the longitudinal direction (AG) and the height direction (AE),

wherein the outflow pipe (8) has:

an outflow inlet (8A) into which exhaust flows; and

an outflow outlet (8B) from which exhaust outflows,

wherein the outflow pipe (8) includes;

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) that are connected in series;

wherein the first outflow pipe (81) has;

a first outflow inlet (8A) into which exhaust flows; and

a first outflow outlet (81B) from which exhaust outflows, the first outflow inlet (81A) being the outflow inlet (8A);

wherein the first outflow pipe (81) is in the vicinity of the first main body wall (42A) with respect to the height direction (AE) and is in the vicinity of a center (LS) of the muffler main body (41) with respect to the width direction (AF),

wherein the second outflow pipe (82) has;

a second outflow inlet (82A) into which exhaust flows; and

a second outflow outlet (82B) from which exhaust outflows, the second outflow inlet (82A) being connected to the first outflow outlet (81B),

wherein, from the second outflow inlet (82A) toward the second outflow outlet (82B), the second outflow pipe (82) approaches the vicinity of the second main body wall (42B) from the vicinity of the first main body wall (42A) with respect to the height direction (AE), and approaches to the vicinity of the third main body wall (42C) from the vicinity of a center (LS) of the muffler main body (41) with respect to the width direction (AF),

wherein the second outflow pipe (82) changes a direction of an exhaust flow from the forward direction (AA) to the reverse direction (AB),

wherein the third outflow pipe (83) has;

a third outflow inlet (83A) into which exhaust flows; and

a third outflow outlet (83B) from which exhaust outflows, the third outflow inlet (83A) being connected to the second outflow outlet (82B),

wherein the third outflow pipe (83) is located in the vicinity of the second main body wall (42B) with respect to the height direction (AE) and is located in the vicinity of the third main body wall (42C) with respect to the width direction (AF),

wherein the fourth outflow pipe (84) has;

a fourth outflow inlet (84A) into which exhaust flows; and

a fourth outflow outlet (84B) from which exhaust outflows, the fourth outflow inlet (84A) being connected to the third outflow outlet (83B),

wherein, from the fourth outflow inlet (84A) to the fourth outflow outlet (84B), the fourth outflow pipe (84) approaches a center (LL) of the muffler main body (41) from the vicinity of the second main body wall (42B) with respect to the height direction (AE) and approaches the vicinity of the fourth main body wall (42D) from the vicinity of the third main body wall (42C) with respect to the width direction (AF),

wherein a direction of an exhaust flow of the fourth outflow pipe (84) changes from the reverse direction (AB) to the forward direction (AA),

wherein the fifth outflow pipe (85) has;

a fifth outflow inlet (85A) into which exhaust flows; and

a fifth outflow outlet (85B) from which exhaust outflows, the fifth outflow inlet (85A) being connected to the fourth outflow outlet (84B), the fifth outflow outlet (85B) being the outflow outlet (8B), and

wherein the fifth outflow pipe (85) is located at a center (LL) of the muffler main body (41) with respect to the height direction (AE) and is located in the vicinity of the fourth main body wall (42D) with respect to the width direction (AF).

27. The exhaust apparatus (2) according to claim 26, wherein the second outflow pipe (82) has a second wall facing part (82B) that is adjacent to the second main body wall (42B),

wherein the fourth outflow pipe (84) has a fourth wall facing part (84A) that is adjacent to the second main body wall (42B), and

wherein the second opening (8C) is provided in at least one of the second wall facing part (82B), the third outflow pipe (83), and the fourth wall facing part (84A).

28. The exhaust apparatus (2) according to claim 26 or claim 27, wherein the muffler main body (41) includes:

a shell body (42) having the muffler chamber (5) therein, the shell body (42) being formed in a cylindrical shape and having a first mouth and a second mouth that is opposite to the first mouth;

a first exterior wall (43) for closing the first mouth;

a second exterior wall (44) for closing the second mouth;

a first interior wall (45), the first interior wall (45) and the first exterior wall (43) defining a first muffling chamber (51);

a second interior wall (46), the first interior wall (45) and the second interior wall (46) defining a second muffling chamber (52), the second interior wall (46) and the second exterior wall (44) defining a third muffling chamber (53), the first muffling chamber (51), the second muffling chamber (52), and the third muffling chamber (53) configuring the muffling chamber (5), the first interior wall (45) having holes (45H, 45I) that connect the first muffling chamber (5) with the second muffling chamber (5);

an inner pipe (9) connecting the second muffling chamber (5) with the third muffling chamber (53); and

a valve device (91) for opening and closing the inner pipe (9), the valve device (91) being open in the case where a pressure of the third muffling chamber (53) is equal to or greater than a threshold value, the valve device (91) being closed in the case where a pressure of the third muffling chamber (53) is smaller than the threshold value,

wherein the inflow pipe (7) has a hole (72H) that connects a passage (7R) of the inflow pipe (7) to the second muffling chamber (5),

wherein the inflow pipe (7) has an inflow outlet (7B) from which exhaust outflows, the inflow outlet (7B) being located in the third muffling chamber (5), and

wherein the outflow pipe (8) has an outflow inlet (8A) into which exhaust flows, the outflow inlet (8A) including locating in the first muffling chamber (5).

29. The exhaust apparatus (2) according to any one of claims 17 to 28, wherein the muffler main body (41) has a third main body wall (42C) and a fourth main body wall (42D), each of which connects the first main body wall (42A) to the second main body wall (42B),

wherein the inflow pipe (7) has:

an inflow inlet (7A) into which exhaust flows; and

an inflow outlet (7B) from which exhaust outflows,

wherein the inflow inlet (7A) exists at a center (LL) in a height direction (AE) of the muffler main body (41), and

wherein the inflow pipe (7) is located in the vicinity of the third main body wall (42C) with respect to a width direction (AF) of the muffler main body (41).

30. The exhaust apparatus (2) according to any one of claims 1 to 29, wherein the exhaust pipe (3) includes:

a main pipe (34A) oriented to the engine (11); and

a first branch pipe (34B) being branched from the main pipe (34A), the first branch pipe being connected to the first muffler (4A), and a second branch pipe (34C) being connected to the second muffler (4B).

31. A vehicle (1) mounting the exhaust apparatus (2) according to any one of claims 1 to 30.

4. An exhaust apparatus (2) for an engine (11) of a vehicle (1), the exhaust apparatus comprising:

an exhaust pipe (3) through which exhaust of the engine (11) flows; and

a first muffler (4A) and a second muffler (4B) arranged in a transverse direction of the vehicle (1), the first muffler (4A) and the second muffler (4B) being connected to the exhaust pipe (3) while being vertically inverted with respect to each other;

wherein the first muffler (4A) and the second muffler (4B) each includes;

a muffler main body (41) having a muffling chamber (5) for muffling the exhaust;

an inflow pipe (7) for allowing exhaust of the exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside, the muffler main body (41) having a main body outlet (44A) for supporting the outflow pipe (8), the main body outlet (44A) being located at a center (LL) in a height direction (AE) of the muffler main body (41).

5. The exhaust apparatus (2) according to claim 4, wherein the outflow pipe (8) has an outflow outlet (8B) from which exhaust outflows, and

wherein the main body outlet (44A) supports the outflow outlet (8B).

6. The exhaust apparatus (2) according to claim 4, wherein the outflow pipe (8) has an outflow outlet (8B) that serves as an outlet of exhaust,

wherein the outflow outlet (8B) extends through the main body outlet (44A), and then, is disposed at the outside of the muffler main body (41), and

wherein a portion of the outflow pipe (8) located at the outside of the muffler main body (41) extends straight.

18. An exhaust apparatus (2) for an engine (11) of a vehicle (1), the exhaust apparatus (2) comprising:

an exhaust pipe (3) through which exhaust of the engine (11) flows; and

a first muffler (4A) and a second muffler (4B) arranged in a transverse direction of the vehicle (1), the first muffler (4A) and the second muffler (4B) being connected to the exhaust pipe (3) while being vertically inverted with respect to each other,

wherein the first muffler (4A) and the second muffler (4B) each includes;

a muffler main body (41) having a muffling chamber (5) for muffling exhaust;

an inflow pipe (7) for allowing exhaust of the exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside,

wherein the muffler main body (41) has a first main body wall (42A) and a second main body wall (42B) that are opposite to each other in a height direction (AE), the muffling chamber (5) existing between the first main body wall (42A) and the second main body wall (42B), and

wherein the outflow pipe (8) has;

a first opening (8A) that connects a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the first main body wall (42A); and

a second opening (8C) that connects a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the second main body wall (42B).

32. A method for manufacturing an exhaust apparatus (2), the exhaust apparatus (2) comprising:

a first muffler (4A) and a second muffler (4B) that are arranged in a transverse direction of a vehicle (1); and

an exhaust pipe (3) that causes exhaust of the engine (11) to flow into the first muffler (4A) and the second muffler (4B), the method comprising;

preparing the first muffler (4A) and the second muffler (4B), the first muffler (4A) and the second muffler (4B) each comprising a muffler main body (41) having a muffling chamber (5);

an inflow pipe (7) for allowing exhaust of the exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside, the outflow pipe (8) having an outflow outlet (8B) from which exhaust outflows, the outflow outlet (8B) being located at a center (LL) of a height direction (AE) of the muffler main body (41);

connecting the first muffler (4A) to the exhaust pipe (3); and

connecting the second muffler (4B) to the exhaust pipe (3) while vertically inverting the second muffler with respect to the first muffler (4A).

33. A method for manufacturing an exhaust apparatus (2), the exhaust apparatus (2) comprising:

a first muffler (4A) and a second muffler (4B) that are arranged in a transverse direction of a vehicle (1); and

an exhaust pipe (3) that causes exhaust of the engine (11) flow into the first muffler (4A) and the second muffler (4B), the method comprising;

preparing the first muffler (4A) and the second muffler (4B), the first muffler (4A) and the second muffler (4B) each comprising;

a muffler main body (41) having a muffling chamber (5);

an inflow pipe (7) for allowing exhaust of the exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside, the muffler main body (41) having a first main body wall (42A) and a second main body wall (42B) that are opposite to each other in a height direction (AE) while the muffling chamber (5) is located therebetween, the outflow pipe (8) having;

a first opening (8A) that connects a passage (8R) in the outflow pipe (8) with the muffling chamber (5) in the vicinity of the first main body wall (42A); and

a second opening (8C) that connects a passage (8R) in the outflow pipe (8) with the muffling chamber (5) in the vicinity of the second main body wall (42B);

connecting the first muffler (4A) to the exhaust pipe (3); and

connecting the second muffler (4B) to the exhaust pipe (3) while vertically inverting the second muffler with respect to the first muffler (4A).

34. The method according to claim 33, wherein the first main body wall (42A) of the first muffler (41) is located vertically downwardly of the second main body wall (42B) of the first muffler (41), and

wherein the second main body wall (42B) of the second muffler (4B) is located vertically downwardly of the first main body wall (42A) of the second muffler (4B).

35. A muffler, comprising:

a muffler main body (41) having a muffling chamber (5);

an inflow pipe (7) for allowing exhaust of an exhaust pipe (3) to flow into the muffling chamber (5); and

an outflow pipe (8) for discharging exhaust of the muffling chamber (5) to the outside,

wherein the muffler main body (41) has a first main body wall (42A) and a second main body wall (42B) that are opposite to each other in a height direction (AE) while the muffling chamber (5) is located therebetween,

wherein the outflow pipe (8) has;

a first opening (8A) that connects a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the first main body wall (42A); and

a second opening (8C) that connects, a passage (8R) of the outflow pipe (8) with the muffling chamber (5) in the vicinity of the second main body wall (42B),

wherein, in the case where the muffler is set at a reference posture, the first main body wall (42A) is located vertically downwardly of the second main body wall (42B), a liquid staying on the first main body wall (42A) can flow into a passage (8R) of the outflow pipe (8) through the first opening (8A), and

wherein, in the case where the muffler is vertically inverted with respect to the reference posture, a liquid staying on the second main body wall (42B) can flow into a passage (8R) of the outflow pipe (8) through the second opening (8C).