JP2010248909A - Exhaust device for outboard engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the sealing performance of an exhaust pipe extending from one side to the other side of a member at the side of an engine. <P>SOLUTION: This exhaust device for the outboard engine includes the exhaust pipe 13 to form a catalyst exhaust passage extending from one side to the other side of a guide exhaust 2. The exhaust pipe 13 has an expansion portion 112 in an area extending in the cross direction of the outboard engine. The expansion portion 112 is so formed that a pipe member (an inner cylinder 82) located at the other side is movable in cross direction relative to a pipe member (an outer cylinder 82) located at one side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust device for an outboard motor having an exhaust pipe extending from one side portion of the outboard motor main body having an engine to the other side portion, and a catalyst provided in the exhaust pipe.

  A conventional general outboard motor exhaust system has a configuration in which exhaust gas is discharged into water mainly in a propeller portion. In order to equip this type of exhaust device with a catalytic converter for purifying exhaust gas (hereinafter simply referred to as catalyst), it is desirable to dispose the catalyst as high as possible. This is because in an outboard motor, water may rise in the exhaust passage to the vicinity of the engine.

As an exhaust device for an outboard motor in which the catalyst is disposed at a high position, for example, there is one described in Patent Document 1.
The exhaust system catalyst disclosed in Patent Document 1 is disposed at substantially the same height as the guide exhaust that supports the engine.

  The exhaust passage of the exhaust device disclosed in Patent Document 1 includes an upstream exhaust passage extending from the exhaust port of the engine to the guide exhaust, a downstream exhaust passage extending downward from the guide exhaust, and the upstream exhaust passage. And a downstream exhaust passage and a catalyst exhaust passage communicating with the outside of the guide exhaust. The downstream end of the upstream exhaust passage opens as an exhaust outlet at one side of the guide exhaust. The upstream end of the downstream exhaust passage opens as an exhaust inlet on the other side of the guide exhaust.

  The catalyst exhaust passage is formed by an exhaust pipe containing a catalyst. The exhaust pipe includes a right side portion extending rearward from the exhaust outlet to the right side of the guide exhaust, a left side portion extending rearward from the exhaust inlet to the left side of the guide exhaust, and a rear end portion of the right side portion. And a catalyst housing portion that connects the rear end portion of the left side portion behind the guide exhaust.

  The front end portion of the right side portion is attached to the right side portion of the guide exhaust from the side. The front end of the left side is attached to the left side of the guide exhaust from the side. In addition, a cooling water passage is formed in the exhaust pipe to cool the catalyst.

JP 2002-256860 A

  In the exhaust device described in Patent Document 1, exhaust gas and cooling water may leak from the connection portion between the guide exhaust and the exhaust pipe, the connection portion between the catalyst housing portion and the left and right side portions of the exhaust pipe, and the like during engine operation. was there. The reason why the exhaust gas and the cooling water leak in this way is that there is a difference between the thermal expansion amount of the guide exhaust and the thermal expansion amount of the exhaust pipe. In other words, the connection portion is distorted due to the difference in thermal expansion amount to form a minute gap, and exhaust gas and cooling water leak from the gap.

  The present invention has been made to solve such a problem, and is an exhaust of an outboard motor capable of improving the sealing performance of an exhaust pipe extending from one side of an engine side member to the other side. An object is to provide an apparatus.

  In order to achieve this object, an outboard motor exhaust system according to the present invention includes an exhaust outlet of an upstream side exhaust passage formed in one side portion of an outboard motor main body having an engine, and the outboard motor main body. One end is connected to the exhaust inlet of the downstream side exhaust passage formed on the other side and the exhaust outlet, and the other end is connected to the exhaust inlet, and the catalyst exhaust is disposed outside the outboard motor main body. In an exhaust system for an outboard motor comprising an exhaust pipe that forms a passage and a catalyst provided in the exhaust pipe, a portion of the exhaust pipe that extends in the width direction of the outboard motor is disposed on one side. The tube member located on the other side with respect to the located tube member is provided with an extendable part that can move in the width direction.

  According to a second aspect of the present invention, in the exhaust apparatus for an outboard motor according to the first aspect, the telescopic portion is movably fitted into an outer cylinder made of a pipe member on one side and the outer cylinder. It is constituted by an inner cylinder composed of a pipe member on the other side, and a seal member is provided between the outer cylinder and the inner cylinder.

  According to a third aspect of the present invention, in the exhaust apparatus for an outboard motor according to the second aspect, the seal member is an O-ring, a cooling water passage is formed in each of the outer cylinder and the inner cylinder, A cooling water passage of the outer cylinder and a cooling water passage of the inner cylinder are formed so as to extend to a fitting portion between the outer cylinder and the inner cylinder.

  According to a fourth aspect of the present invention, in the exhaust apparatus for an outboard motor according to the third aspect, the seal member is provided on one end side and the other end side of the fitting portion, and the seal member is provided between the seal members. A cooling water passage formed of an annular groove opened on the inner peripheral surface of the outer cylinder or the outer peripheral surface of the inner cylinder is formed.

  According to a fifth aspect of the present invention, in the exhaust device for an outboard motor according to the fourth aspect, the cooling water passage of the outer cylinder and the cooling water passage of the inner cylinder are arranged via the cooling water passage made of the annular groove. Communicated with each other.

In the present invention, when an external force is applied in the width direction of the outboard motor to one end portion and the other end portion in the width direction of the exhaust pipe, in the expansion / contraction portion of the exhaust pipe, The tube member moves in the width direction. For this reason, the exhaust pipe is deformed so as to follow the thermal expansion of the outboard motor main body even though the thermal expansion amount is greatly different from that of the outboard motor main body.
Therefore, according to the present invention, since the connecting portion between the exhaust pipe and the outboard motor main body can be prevented from being distorted due to the difference in thermal expansion amount, the exhaust device for the outboard motor having high sealing performance of the connecting portion. Can be provided.

1 is a side view of an outboard motor equipped with an exhaust device according to the present invention. It is a top view of a guide exhaust and an exhaust pipe. It is a bottom view of a guide exhaust and an exhaust pipe. It is the IV-IV sectional view taken on the line of the principal part in FIG. It is the VV sectional view taken on the line of the principal part in FIG. FIG. 6 is a cross-sectional view of the exhaust pipe taken along line VI-VI in FIG. 1. It is a longitudinal cross-sectional view of a drain discharge valve. It is the VIII-VIII sectional view taken on the line of the exhaust pipe in FIG. It is the side view seen from the right side of the left exhaust pipe. It is the side view seen from the left side of a right side exhaust pipe and a catalyst housing. It is a side view of a catalyst. It is the XII-XII sectional view taken on the line in FIG. It is the side view which looked at the rear end part of the right exhaust pipe from the left side.

Hereinafter, an embodiment of an exhaust apparatus for an outboard motor according to the present invention will be described in detail with reference to FIGS. 1 to 4, the front of the outboard motor is indicated by an arrow F.
An outboard motor 1 shown in FIG. 1 includes a guide exhaust 2 attached to a hull (not shown), an engine 3 mounted on the guide exhaust 2, and an upper casing 4 attached below the guide exhaust 2. The lower casing 5 attached to the lower end portion of the upper casing 4, the propeller 6 rotatably supported by the lower casing 5, and the exhaust device that discharges exhaust gas of the engine 3 from the shaft center portion of the propeller 6 into the water. 7 etc.

Although not shown, the guide exhaust 2 has a steering shaft connected to the front end portion thereof, and is supported on the hull side bracket via the steering shaft so as to be steerable and tiltable. The guide exhaust 2 and the engine 3 constitute an outboard motor body 8 in the present invention.
As shown in FIG. 5, a left passage hole 2a constituting a part of the upstream exhaust passage 9 referred to in the present invention is formed in one side portion of the guide exhaust 2 on the left side of the outboard motor. The left passage hole 2 a is formed so as to open on the upper surface and the left side surface of the guide exhaust 2.

  The upstream exhaust passage 9 is formed by a passage hole (not shown) formed in the cylinder head 10 (see FIG. 1) and the cylinder body 11 of the engine 3 and the left passage hole 2a. The exhaust gas of the engine 3 flows through the upstream exhaust passage 9 and is discharged out of the guide exhaust 2 from the exhaust outlet 12 (see FIG. 5) of the left passage hole 2a. The exhaust gas discharged from the exhaust outlet 12 flows into an exhaust pipe 13 (see FIGS. 2 and 3) described later, and is guided to the opposite side of the outboard motor 1 in the width direction (right side of the outboard motor) by the exhaust pipe 13. It is burned.

  As shown in FIG. 5, a right passage hole 2b into which the exhaust gas guided by the exhaust pipe 13 flows is formed on one side of the guide exhaust 2 on the right side of the outboard motor. The right passage hole 2b constitutes a part of the downstream exhaust passage 15 referred to in the present invention. The right passage hole 2b opens as an exhaust inlet 16 on the right side surface of the guide exhaust 2 and also opens on the lower surface of the guide exhaust 2. .

An oil pan 17 is attached to the lower end of the guide exhaust 2 as shown in FIGS. 4 and 5. The oil pan 17 is formed with an oil reservoir 18 that opens upward and an exhaust passage 19 for guiding the exhaust gas downward.
The opening at the upper end of the oil reservoir 18 is closed by the guide exhaust 2. The oil flows down into the oil reservoir 18 from an oil return port 20 (see FIGS. 2 to 5) formed in a substantially central portion of the guide exhaust 2.

  As shown in FIG. 5, the exhaust passage 19 of the oil pan 17 is formed on one side of the oil pan 17 on the right side of the outboard motor so as to penetrate the oil pan 17 in the vertical direction. The opening at the upper end of the exhaust passage 19 is formed at a position facing the opening at the lower end of the right passage hole 2b. The lower end of the exhaust passage 19 opens into the upper end portion of the muffler 21 attached to the lower end portion of the oil pan 17.

  As shown in FIG. 1, the muffler 21 extends in the upper casing 4 to the vicinity of the lower casing 5, and is formed so that exhaust gas is discharged into an exhaust passage 22 in the lower casing 5. The exhaust passage 22 in the lower casing 5 communicates with water in the axial center portion of the propeller 6.

The downstream exhaust passage referred to in the present invention is defined by the internal space of the right passage hole 2b of the guide exhaust 2, the exhaust passage 19 of the oil pan 17, the internal space of the muffler 21, and the exhaust passage 22 in the lower casing 5. 15 is configured.
As shown in FIG. 5, a water chamber 23 is formed between the upper casing 4 and the oil pan 17 for guiding cooling water discharged from a cooling water passage of the engine 3 and an exhaust pipe 13 described later. Has been.

As shown in FIGS. 2 and 3, the exhaust pipe 13 includes a left exhaust pipe 31 extending from one side of the left side of the outboard motor of the guide exhaust 2 to the rear of the outboard motor, and a ship of the guide exhaust 2. A right exhaust pipe 32 extending rearward from the other side on the right side of the outer unit, and a communication pipe 33 connecting the left exhaust pipe 31 and the rear end portions of the right exhaust pipe 32 are provided.
The left exhaust pipe 31 is for guiding exhaust gas discharged from the exhaust outlet 12 of the guide exhaust 2 to a catalytic converter (hereinafter simply referred to as catalyst) 34 described later.

  2, 3 and 9, the left exhaust pipe 31 includes an exhaust pipe main body 35 extending in the front-rear direction on the left side of the guide exhaust 2, and an outboard from the rear end of the exhaust pipe main body 35. The left catalyst housing half 36 extends to the right side of the machine, and the left idle muffler half 37 extends rearward and downward from the left catalyst housing half 36. The exhaust pipe main body 35, the left catalyst housing half 36, and the left idle muffler half 37 are integrally formed by casting.

  The left exhaust pipe 31 is supported by the guide exhaust 2 via these connection parts by connecting the front end part of the exhaust pipe body 35 and the front end part of the left catalyst housing half part 36 to the guide exhaust 2. Yes. As shown in FIGS. 2 and 3, the front end portion of the exhaust pipe main body 35 overlaps the left side portion of the guide exhaust 2 from the side and is fixed by fixing bolts 38 and 39.

A bracket 36 a that projects forward is integrally formed at the front end of the left catalyst housing half 36. As shown in FIG. 4, the front end portion of the bracket 36 a is elastically supported by the rear end portion of the guide exhaust 2 via the mount member 40.
As shown in FIG. 8, an exhaust passage 41 and a cooling water passage 42 that surrounds the exhaust passage 41 are formed in the exhaust pipe main body 35 and the left catalyst housing half 36.

  The exhaust passage 41 and the cooling water passage 42 are formed so as to extend from the upstream end (front end portion) of the left exhaust pipe 31 to the downstream end (end portion on the right side of the outboard motor of the left catalyst housing half 36). Has been. The upstream end of the exhaust passage 41 is connected to the exhaust outlet 12 of the guide exhaust 2. One end of the cooling water passage 42 is connected to a cooling water passage 43 (see FIG. 5) of the guide exhaust 2.

An air-fuel ratio sensor 44 (see FIG. 9) composed of an O ₂ sensor is attached to the rear end portion of the exhaust pipe main body 35. The air-fuel ratio sensor 44 is inserted into a mounting hole 45 (see FIG. 2) formed on the upper side of the rear end portion of the exhaust pipe main body 35.
The left catalyst housing half 36 is for supporting the catalyst 34 in cooperation with a communication pipe 33 described later, and is formed in a cylindrical shape so that the upstream half of the catalyst 34 is accommodated. ing.

Although the catalyst 34 used in this embodiment is not shown in detail, it is called a so-called metal catalyst, and a stainless steel plate-like carrier 46 wound in a spiral shape (see FIG. 8). And a cylinder 47 into which the plate-like carrier 46 is inserted, a fixing flange 48 welded to the central portion in the axial direction of the outer periphery of the cylinder 47, and the like.
The outer shape of the plate-like carrier 46 is formed to be a perfect circle (see FIG. 4) when viewed from the direction in which the exhaust gas flows so that the spiral winding operation can be simplified and easily manufactured. In FIG. 4, the plate-like carrier 46 wound in a spiral shape is simplified and drawn simply in a mesh shape.

  As shown in FIG. 8, the fixing flange 48 is fixed to the left catalyst housing half 36 together with the communication pipe 33 while being sandwiched between the left catalyst housing half 36 and a communication pipe 33 described later. (See FIGS. 2, 3 and 6). The fixing bolt 49 is inserted through a through hole 50 (see FIG. 11) formed in the fixing flange 48.

The fixing flange 48 is provided on the outside of the cylinder 47 so that the exhaust gas passes only from the left catalyst housing half 36 through the cylinder 47 and flows to the communication pipe 33 side. 41 and the exhaust passage 51 in the communication pipe 33 are partitioned.
As shown in FIG. 11, the fixing flange 48 shown in this embodiment is formed so as to extend below and behind the cylinder 47 (on the right side in FIG. 11). As shown in FIGS. 6 and 8, the extending portion 48 a partitions the inside of the idle muffler 52 provided below the catalyst 34 in the width direction of the outboard motor 1.

  As shown in FIG. 9, a hose joint 53 is provided at the upper end portion of the left catalyst housing half 36 to discharge a part of the cooling water from the cooling water passage 42 and the bubbles in the cooling water passage 42. Installed. The hose joint 53 is connected to, for example, the cooling water passage 43 of the guide exhaust 2 by a cooling water hose (not shown).

  As shown in FIG. 6, a drain passage 54 is formed at the lower end of the left catalyst housing half 36 to discharge water generated in the exhaust passage 41. Examples of water generated in the exhaust passage 41 include exhaust condensed water and condensed water. Exhaust condensed water is obtained by cooling and condensing moisture contained in the exhaust gas in the exhaust passage 41. Further, the dew condensation water is a dew condensation of moisture in the exhaust passage 41 on the wall surface of the exhaust passage 41 cooled after the engine is stopped.

The drain passage 54 is formed so as to extend from the open end of the left catalyst housing half 36 to the left side of the outboard motor in the lower end portion of the left catalyst housing half 36, and the left side surface of the left catalyst housing half 36. Is open.
An annular space S 1 is formed between the left catalyst housing half 36 and the cylinder 47 of the catalyst 34. The upstream end of the drain passage 54 (one end on the opening end side of the left catalyst housing half 36) opens to the lowest part of the space S1. For this reason, the exhaust condensed water and the dew condensation water in the left exhaust pipe 31 are discharged from the space S1 into the drain passage 54.

  The other end of the drain passage 54 is connected to, for example, the water chamber 23 of the upper casing 4 via a float type on-off valve 55 and a hose (not shown). As shown in FIG. 7, the on-off valve 55 includes a float 59 supported by a valve housing 56 via a support shaft 57 and a lever 58 so as to be swingable, and a valve body provided at an intermediate portion of the lever 58. 60 and a spring member 61 for urging the float 59 downward. The on-off valve 55 is opened when exhaust condensate or dew condensation water is stored in the valve housing 56 and the float 59 moves upward. The reason why the on-off valve 55 is provided in the drain passage 54 is to prevent exhaust gas from passing through the drain passage 54 from the upstream side of the catalyst 34 and being discharged.

  The left idle muffler half 37 cooperates with a fixing flange 48 of the catalyst 34, a right idle muffler half 62 (see FIGS. 6 and 8) of the communication pipe 33 described later, and the like. It constitutes. The idle muffler 52 emits exhaust gas when the engine 3 is in an idling operation state or a low speed operation state (when there is no exhaust pressure that can discharge water entering the exhaust passage 22 in the lower casing 5). The sound is silenced and discharged out of the outboard motor 1.

  The left idle muffler half 37 is substantially box-shaped and opens toward the right side of the outboard motor 1 and extends rearward and downward from the left catalyst housing half 36 as shown in FIG. It is formed to do. The inside of the left idle muffler half 37 according to this embodiment is divided into a front expansion chamber 65, a central expansion chamber 66 and a rear expansion chamber 67 by a front partition wall 63 and a rear partition wall 64. These expansion chambers 65 to 67 become independent air chambers when the fixing flange 48 of the catalyst 34 is overlapped on the left idle muffler half 37. The front partition wall 63 and the rear partition wall 64 are formed with communication holes 68 and 69 for flowing exhaust gas, respectively.

The front expansion chamber 65 is communicated with the inside of a right idle muffler half 62 described later by two communication holes 70 (see FIG. 11) formed in the fixing flange 48.
The central expansion chamber 66 communicates with the front expansion chamber 65 through a communication hole 68 formed in the front partition wall 63 and communicates with the rear expansion chamber 67 through a communication hole 69 formed in the rear partition wall 64. .

The rear expansion chamber 67 is communicated with the right idle muffler half 62 through two communication holes 71 (see FIG. 11) formed in the fixing flange 48.
A hose joint 72 is attached to the lower end of the left idle muffler half 37 according to this embodiment in order to discharge water (exhaust condensed water or condensed water) stored in the central expansion chamber 66. The hose joint 72 is connected to the water chamber 23 of the upper casing 4 by a hose (not shown), for example.

  As shown in FIGS. 6, 8, and 10, the communication pipe 33 includes a right catalyst housing half 81 that holds the catalyst 34 in cooperation with the left catalyst housing half 36, and the left idle muffler half. 37, a right idle muffler half 62 that constitutes the idle muffler 52 in cooperation with the engine 37, and an inner cylinder 83 that fits into an outer cylinder 82 of the right exhaust pipe 32 described later. The right catalyst housing half 81, the right idle muffler half 62, and the inner cylinder 83 are integrally formed by casting.

  The right catalyst housing half 81 is formed in a cylindrical shape so that the downstream half of the catalyst 34 is accommodated. A cooling water passage 84 is also formed in the right catalyst housing half 81 so as to surround the exhaust passage 51 on the downstream side of the catalyst. As shown in FIG. 8, the cooling water passage 84 is connected to the cooling water passage 42 of the left catalyst housing half 36 by a communication hole 85 formed in the fixing flange 48.

An annular space S2 is formed between the right catalyst housing half 81 and the cylinder 47 of the catalyst 34.
Further, as shown in FIGS. 4 and 6, a drain hole 86 for discharging exhaust condensed water, condensed water and the like from the exhaust passage 51 on the downstream side of the catalyst 34 is formed at the lower end of the right catalyst housing half 81. Is formed. The drain hole 86 communicates the exhaust passage 51 and the right idle muffler half 62 located below the catalyst 34.

  The water flowing down from the drain hole 86 into the right idle muffler half 62 is a hose joint 87 (see FIG. 10) attached to the lower end of the right idle muffler half 62, and a hose connected to the joint. (Not shown) and discharged into the water chamber 23 of the upper casing 4, for example. That is, the exhaust condensed water and the dew condensation water are discharged from the exhaust passage 51 on the downstream side of the catalyst 34 through the inside of the idle muffler 52.

  As shown in FIG. 10, the right idle muffler half 62 is shaped to be a target in the width direction of the left idle muffler half 37 and the outboard motor 1, and faces the left side of the outboard motor 1. It is formed in a substantially box shape that opens. In the right idle muffler half 62 according to this embodiment, a front expansion chamber 90, a central expansion chamber 91, and a rear expansion chamber 92 are formed by a front partition wall 88 and a rear partition wall 89. These expansion chambers 90 to 92 become independent air chambers when the fixing flange 48 of the catalyst 34 is overlapped on the right idle muffler half 62. A communication hole 93 for flowing exhaust gas is formed in the front partition wall 88.

The front expansion chamber 90 is communicated with the front expansion chamber 65 in the left idle muffler half 37 through the communication hole 70 (see FIG. 11) formed in the fixing flange 48.
The central expansion chamber 91 communicates with the exhaust passage 51 on the downstream side of the catalyst through the drain hole 86 and communicates with the front expansion chamber 90 through the communication hole 93 of the front partition wall 88.

  The rear expansion chamber 92 is communicated with the rear expansion chamber 67 in the left idle muffler half 37 through the communication hole 71 (see FIG. 11) formed in the fixing flange 48. An exhaust outlet pipe 94 for discharging exhaust gas from the rear expansion chamber 92 is provided at the rear end of the right idle muffler half 62.

  That is, when the engine 3 performs a low speed operation including an idling operation, the exhaust gas is communicated from the exhaust passage 51 on the downstream side of the catalyst 34 to the drain hole 86 → the central expansion chamber 91 in the right idle muffler half 62 → the communication. Hole 93-> front expansion chamber 90-> front communication hole 70 of flange 48-> front expansion chamber 65 in left idle muffler half 37-> communication hole 68-> central expansion chamber 66-> communication hole 69-> rear expansion chamber 67-> flange 48 is discharged into the atmosphere through a path of the rear communication hole 71 → the rear expansion chamber 92 in the right idle muffler half 62 → the exhaust outlet pipe 96.

  The idle muffler 52 according to this embodiment is configured such that exhaust condensate or dew condensation water from the front expansion chambers 65 and 90 and the rear expansion chambers 67 and 92 of the left and right idle muffler halves 37 and 62 is expanded in the center of the right idle muffler half 62. It is configured to gather in the chamber 91. That is, the lowest part of the front expansion chamber 90 in the right idle muffler half 62 is the front expansion chamber in the left idle muffler half 37 by the communication hole 95 (see FIG. 11) drilled in the fixing flange 48. 65 is communicated.

Further, the lowest part of the rear expansion chamber 92 in the right idle muffler half 62 is the rear expansion chamber in the left idle muffler half 37 by the communication hole 96 (see FIG. 11) formed in the flange 48. 67 is communicated.
Further, a communication groove for flowing exhaust condensate or dew condensation water in the lower end of the front partition 88 and the lower end of the rear partition 89 facing the fixing flange 48 in the right idle muffler half 62. 97 (see FIG. 10) is formed.

  As shown in FIGS. 8 and 12, the inner cylinder 83 of the communication pipe 33 is formed in a cylindrical shape having an outer diameter smaller than that of the right catalyst housing half 81. The inner cylinder 83 is provided at an end portion on the right side of the outboard motor of the right catalyst housing half 81 so that the axial direction is oriented in the width direction of the outboard motor 1. That is, the inner cylinder 83 is provided in a portion of the exhaust pipe 13 that extends in the width direction of the outboard motor 1. The inner cylinder 83 constitutes a tube member on the other side referred to in the invention of claim 1.

The hollow portion of the inner cylinder 83 forms an exhaust passage 51 on the downstream side of the catalyst in cooperation with the right catalyst housing half 81. A cooling water passage 101 communicating with the cooling water passage 84 of the right catalyst housing half 81 is formed in the peripheral wall of the inner cylinder 83. The cooling water passage 101 is formed so as to extend from one end portion of the inner cylinder 83 to the other end portion.
Two O-rings 102 as sealing members referred to in the present invention are attached to the outer peripheral portion of the inner cylinder 83.

  The O-ring 102 is provided on one end side and the other end side of the inner cylinder 83. Between the two O-rings 102 at the outer peripheral portion of the inner cylinder 83, a cooling water passage formed of an annular groove 103 opened on the outer peripheral surface of the inner cylinder 83 is formed. As shown in FIGS. 8 and 12, this cooling water passage is communicated with the cooling water passage 101 of the inner cylinder 83 through a communication hole 104 that opens to the bottom of the annular groove 103. In FIG. 8, the communication hole 104 is drawn so as to be located at the rear end portion of the inner cylinder 83, but this communication hole 104 is actually formed in the inner cylinder 83 as shown in FIG. It is formed at the lower end.

  The right exhaust pipe 32 is for guiding the exhaust gas after passing through the catalyst 34 to the downstream exhaust passage 15 on the guide exhaust 2 side. As shown in FIG. 2, the right exhaust pipe 32 includes an exhaust pipe main body 105 extending in the front-rear direction on the right side of the guide exhaust 2 and a cylindrical body provided at the rear end of the exhaust pipe main body 105. An outer cylinder 82 is used. The exhaust pipe main body 35 and the outer cylinder 82 are integrally formed by casting.

The right exhaust pipe 32 is supported by the guide exhaust 2 and the communication pipe 33 by connecting the front end of the exhaust pipe main body 105 to the guide exhaust 2 and connecting an outer cylinder 82 to be described later to the communication pipe 33. Has been.
As shown in FIGS. 2 and 3, the front end portion of the exhaust pipe main body 105 is overlapped with the right side portion of the guide exhaust 2 from the side and fixed by fixing bolts 106 and 107.

  As shown in FIG. 8, the exhaust pipe main body 105 and the outer cylinder 82 are formed with an exhaust passage 108 and a cooling water passage 109 surrounding the exhaust passage 108. The exhaust passage 108 and the cooling water passage 109 are formed so as to extend from the downstream end (front end portion) of the right exhaust pipe 32 to the upstream end (tip portion of the outer cylinder 82). The downstream end of the exhaust passage 108 is connected to the exhaust inlet 16 of the guide exhaust 2. One end of the cooling water passage 109 located on the guide exhaust 2 side is connected to the cooling water passage 43 (see FIG. 5) of the guide exhaust 2.

An air-fuel ratio sensor 110 (see FIG. 10) composed of an O ₂ sensor is attached to the rear end portion of the exhaust pipe main body 105. The air-fuel ratio sensor 110 is inserted into a mounting hole 111 (see FIG. 2) formed on the upper side of the rear end portion of the exhaust pipe main body 35. In the outboard motor 1 according to this embodiment, the fuel injection amount, the ignition timing, etc., based on the detection result of one of the air-fuel ratio sensor 110 and the air-fuel ratio sensor 44 provided in the left exhaust pipe 31. And an abnormality of the catalyst 34 is detected using both air-fuel ratio sensors. The detection of this abnormality is performed by comparing the upstream oxygen amount and the downstream oxygen amount of the catalyst 34, as is well known.

  As shown in FIGS. 8 and 12, the outer cylinder 82 is formed in a cylindrical shape. The outer cylinder 82 is provided at the rear end portion of the exhaust pipe main body 105 so that the axial direction is oriented in the width direction of the outboard motor 1. That is, the outer cylinder 82 is provided in a portion of the exhaust pipe 13 that extends in the width direction of the outboard motor 1. The outer cylinder 82 constitutes one side pipe member as referred to in the first aspect of the invention.

Further, the inner diameter of the outer cylinder 82 is formed so that the inner cylinder 83 can be movably fitted in the outer cylinder 82. The length of the outer cylinder 82 in the axial direction is such that two O-rings 102 provided in the inner cylinder 83 are inserted into the outer cylinder 82.
That is, the outer cylinder 82 and the inner cylinder 83 are connected to be movable in the width direction of the outboard motor 1. The outer cylinder 82 and the inner cylinder 83 constitute a stretchable part 112 as used in the present invention.

  As shown in FIG. 8, an end surface 105 a that faces the front end surface 83 a of the inner cylinder 83 (an end surface that faces the right side of the outboard motor) is formed at the connection portion between the outer cylinder 82 and the exhaust pipe body 105. Yes. As shown in FIG. 13, two annular grooves 113 and 114 constituting a labyrinth seal are formed on the end face 105a. These annular grooves 113 and 114 are formed so as to be located on the same axis as the outer cylinder 82.

  As shown in FIG. 12, a hose joint 115 is attached to the upper end portion of the outer cylinder 82 in order to discharge a part of the cooling water from the cooling water passage 109 and to discharge the bubbles in the cooling water passage 109. Yes. The hose joint 115 is connected to, for example, the cooling water passage 43 of the guide exhaust 2 by a cooling water hose (not shown).

  As shown in FIG. 8, the cooling water passage 109 of the outer cylinder 82 is formed so as to extend to the distal end portion (the end portion on the left side of the outboard motor) of the outer cylinder 82, that is, the portion that fits the inner cylinder 83. ing. As shown in FIG. 12, the cooling water passage 109 communicates with the cooling water passage formed of the annular groove 103 of the inner cylinder 83 through a communication hole 116 that opens to the inner peripheral surface 82 a of the outer cylinder 82. Therefore, the cooling water passage 109 of the outer cylinder 82 and the cooling water passage 101 of the inner cylinder 83 are connected to the communication hole 116 on the outer cylinder 82 side, the annular groove 103, and the communication hole 104 on the inner cylinder 83 side. Are in communication with each other.

According to the exhaust device 7 of the outboard motor 1 configured as described above, the exhaust gas is guided to the exhaust pipe 13 when it passes through the guide exhaust 2 and is purified by the catalyst 34 in the exhaust pipe 13.
During engine operation, the guide exhaust 2 and the exhaust pipe 13 are each expanded by heat. The amount of thermal expansion of the guide exhaust 2 and the amount of thermal expansion of the exhaust pipe 13 rarely coincide. For this reason, during engine operation, the outboard motor 1 is connected to the front end of the left exhaust pipe 31 and the front end of the right exhaust pipe 32 due to the difference in thermal expansion between the guide exhaust 2 and the exhaust pipe 13. External force is applied in the width direction.

Thus, when an external force is applied in the width direction of the outboard motor 1 to one end (left exhaust pipe 31) and the other end (right exhaust pipe 32) in the width direction of the exhaust pipe 13, the expansion and contraction of the exhaust pipe 13 is performed. In the portion 112, one of the outer cylinder 82 and the inner cylinder 83 moves in the width direction with respect to the other. For this reason, the exhaust pipe 13 is deformed so as to follow the thermal expansion of the guide exhaust 2 even though the thermal expansion amount is different from that of the guide exhaust 2.
Therefore, according to this embodiment, the connecting portion between the exhaust pipe 13 and the guide exhaust 2 can be prevented from being distorted due to the difference in the amount of thermal expansion, so that the sealing performance of the connecting portion can be kept high.

  According to this embodiment, the right exhaust pipe 32 and the communication pipe 33 (the left exhaust pipe 31) located on the left side are coupled by the fitting of the outer cylinder 82 and the inner cylinder 83 in the expansion / contraction part 112. Yes. For this reason, the strength of the expansion / contraction part 112 can be improved while preventing the function of the exhaust pipe 13 that deforms following the thermal expansion of the guide exhaust 2 from being impaired.

  Further, since the inner cylinder 83 is fitted in the outer cylinder 82, the right exhaust pipe 32 and the communication pipe 33 (left exhaust pipe 31) float in a direction different from the width direction of the outboard motor 1. Can be prevented. For this reason, in the exhaust pipe 13 according to this embodiment, the space between the outer cylinder 82 and the inner cylinder 83 can be reliably sealed by the O-ring 102.

According to this embodiment, the cooling water passage 109 of the outer cylinder 82 and the cooling water passage 101 of the inner cylinder 83 are formed so as to extend to a fitting portion between the outer cylinder 82 and the inner cylinder 83. For this reason, the fitting part of the outer cylinder 82 and the inner cylinder 83 can be cooled with cooling water. That is, the inner cylinder 83, the outer cylinder 82, and the exhaust gas that contacts the O-ring 102 can be cooled.
Therefore, since the temperature of the O-ring 102 can be maintained appropriately, the reliability of the seal portion having the O-ring 102 is increased.

In this embodiment, O-rings 102 are respectively provided at one end and the other end of the fitting portion between the outer cylinder 82 and the inner cylinder 83, and the inner cylinder 83 is provided between these O-rings 102, 102. A cooling water passage composed of an annular groove 103 opened on the outer peripheral surface of the outer peripheral surface is formed.
For this reason, the cooling water passage can be easily formed even at a position where it overlaps the O-ring 102 when viewed from the axial direction of the inner cylinder 83.

Since this cooling water passage is formed in a space sealed by an O-ring 102 for preventing leakage of exhaust gas, a sealing member for exclusively preventing leakage of cooling water is unnecessary.
Therefore, the sealing performance of the expansion / contraction portion 112 of the exhaust pipe 13 can be improved by the two O-rings 102 and 102, and the cooling of the O-ring 102 is promoted to improve the durability of the O-ring 102. be able to.

  In this embodiment, the cooling water passage 109 of the outer cylinder 82 and the cooling water passage 101 of the inner cylinder 83 are communicated with each other via a cooling water passage formed by the annular groove 103 of the inner cylinder 83. For this reason, it is possible to prevent the cooling water from staying in the cooling water passages of the outer cylinder 82 and the inner cylinder 83 at the fitting portion of the outer cylinder 82 and the inner cylinder 83, and thus the O-ring 102 is reliably cooled. Can do.

  In the embodiment described above, an example in which the exhaust pipe 13 is attached to the guide exhaust 2 has been shown. However, the exhaust pipe 13 can be attached to the cylinder body 11. It is also possible to attach one end of the exhaust pipe 13 to the guide exhaust 2 and attach the other end to the cylinder body 11.

  DESCRIPTION OF SYMBOLS 1 ... Outboard motor, 2 ... Guide exhaust, 3 ... Engine, 7 ... Exhaust device, 9 ... Upstream exhaust passage, 12 ... Exhaust outlet, 13 ... Exhaust pipe, 15 ... Downstream exhaust passage, 16 ... Exhaust inlet, 17 ... oil pan, 31 ... left exhaust pipe, 32 ... right exhaust pipe, 33 ... communication pipe, 34 ... catalyst, 35, 105 ... exhaust pipe main body, 36 ... left catalyst housing half, 81 ... right catalyst housing half, 82 ... outer cylinder, 83 ... inner cylinder, 101, 109 ... cooling water passage, 102 ... O-ring, 103 ... annular groove, 112 ... telescopic part.

Claims (5)

An exhaust outlet of the upstream exhaust passage formed on one side of the outboard motor body having the engine;
An exhaust inlet of a downstream exhaust passage formed in the other side of the outboard motor body;
An exhaust pipe having one end connected to the exhaust outlet and the other end connected to the exhaust inlet, and forming a catalyst exhaust passage outside the outboard motor body;
In the exhaust system of an outboard motor comprising a catalyst provided in the exhaust pipe,
A portion of the exhaust pipe that extends in the width direction of the outboard motor is provided with an expansion / contraction portion that allows the pipe member located on the other side to move in the width direction relative to the pipe member located on the one side. Outboard motor exhaust system. 2. The exhaust system for an outboard motor according to claim 1, wherein the expansion / contraction part is composed of an outer cylinder made of a pipe member on one side and a pipe member on the other side movably fitted inside the outer cylinder. It consists of an inner cylinder,
An outboard motor exhaust system in which a seal member is provided between the outer cylinder and the inner cylinder. The exhaust device for an outboard motor according to claim 2, wherein the seal member is an O-ring.
A cooling water passage is formed in each of the outer cylinder and the inner cylinder,
The exhaust device for an outboard motor, wherein the cooling water passage of the outer cylinder and the cooling water passage of the inner cylinder are formed to extend to a fitting portion between the outer cylinder and the inner cylinder.   The exhaust device for an outboard motor according to claim 3, wherein the seal member is provided on one end side and the other end side of the fitting portion, and an inner peripheral surface of an outer cylinder is provided between the seal members. Or the exhaust device of the outboard motor in which the cooling water path which consists of an annular groove opened in the outer peripheral surface of an inner cylinder is formed.   5. The exhaust system for an outboard motor according to claim 4, wherein the cooling water passage of the outer cylinder and the cooling water passage of the inner cylinder communicate with each other via the cooling water passage formed of the annular groove. Exhaust system.

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