JP2010248913A - Exhaust device for outboard engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent exhaust condensed water and dew condensation water produced in exhaust passages from contacting with a catalyst while restricting the exhaust of unpurified exhaust gas. <P>SOLUTION: This exhaust device for an outboard engine includes a catalyst exhaust passage formed near the engine so that exhaust gas flows in the approximately horizontal direction, the catalyst 34 provided in the catalyst exhaust passage, an upstream side drain passage 54 opened at one end to the exhaust passage 41 at the upstream side of the catalyst 34, and a downstream side drain passage 86 opened at one end to the exhaust passage 51 at the downstream side of the catalyst 34. The upstream side drain passage 54 has a drain valve 55 for draining water only out of the exhaust passage while restricting the flow-out of exhaust gas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust device for an outboard motor including an exhaust passage extending in a substantially horizontal direction in the vicinity of an engine and a catalyst provided in the exhaust passage.

  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 catalyst of the exhaust device disclosed in Patent Document 1 is built in an engine holder that supports the engine.

The engine holder is formed with a catalyst exhaust passage extending from one side in the width direction of the outboard motor to the other side through the rear. The catalyst is accommodated in a portion of the exhaust passage that extends in the width direction of the outboard motor.
By the way, it is known that water such as so-called exhaust condensed water or condensed water is generated in the exhaust passage of the engine. Exhaust condensed water is water that is contained in the exhaust gas that is cooled and condensed in the exhaust passage. Further, the dew condensation water is a dew condensation of moisture in the exhaust passage on the wall surface of the exhaust passage that has cooled after the engine is stopped.

Japanese Patent No. 3465430

  In the exhaust apparatus described in Patent Document 1, since the exhaust gas flows in the catalyst in a substantially horizontal direction, there is a possibility that the exhaust condensed water and dew condensation water may stay in the lowest part in the catalyst. When exhaust condensed water or condensed water comes into contact with the catalyst, the catalytic metal is corroded, or the activation of the catalytic metal is hindered due to a temperature drop, so that the purification efficiency is remarkably lowered.

  In order to solve such a problem, it is conceivable to connect the drainage passage to the exhaust passage and discharge the water. In discharging water from the exhaust passage, it is necessary to prevent exhaust gas before being purified by the catalyst from being discharged together with water.

  The present invention has been made to solve such a problem, and it is possible to prevent exhaust condensed water and condensed water generated in the exhaust passage from contacting the catalyst while restricting discharge of unpurified exhaust gas. It is an object of the present invention to provide an outboard motor exhaust device that can be prevented.

  In order to achieve this object, an outboard motor exhaust system according to the present invention is provided in a catalyst exhaust passage formed in the vicinity of an engine so that exhaust gas flows in a substantially horizontal direction, and the catalyst exhaust passage. In the exhaust system for an outboard motor comprising the catalyst, an upstream drainage passage having one end opened in the exhaust passage upstream from the catalyst, and a downstream drainage passage having one end opened in the exhaust passage downstream from the catalyst The upstream drainage passage is provided with a drainage valve that regulates the outflow of exhaust gas and can discharge only the water in the exhaust passage.

  According to a second aspect of the present invention, in the exhaust system for an outboard motor according to the first aspect, the engine is supported by an engine support member, and the upstream exhaust passage that extends downward from the engine is supported by the engine support member. And an exhaust inlet of a downstream exhaust passage extending downward from the engine support member, an upstream end of the catalyst exhaust passage is connected to the exhaust outlet, and a downstream end of the catalyst exhaust passage The catalyst exhaust passage is formed so that water can flow from the upstream end toward the catalyst, and water can flow from the downstream end toward the catalyst. A space into which the water can flow is formed between the inner wall surface of the catalyst exhaust passage and the catalyst, and the upstream drainage passage and the downstream drainage passage are opened in the space.

  An outboard motor exhaust system according to a third aspect of the present invention is the outboard motor exhaust system according to the first or second aspect, wherein an idle muffler that exhausts exhaust gas at idling is provided below the catalyst exhaust passage. And the downstream drainage passage is formed using an exhaust passage of the idle muffler.

  According to a fourth aspect of the present invention, in the exhaust system for an outboard motor according to the third aspect, the idle muffler is integrally formed with an exhaust pipe having the catalyst exhaust passage.

  According to a fifth aspect of the present invention, in the exhaust device for an outboard motor according to the third aspect, the drain valve is accommodated in an idle muffler.

  According to a sixth aspect of the present invention, in the exhaust system for an outboard motor according to the second aspect, an oil pan is attached to a lower end portion of the engine support member, and the catalyst exhaust passage is connected to the ship from the exhaust outlet and the exhaust inlet. An engine support member is formed so as to penetrate the outboard motor in the width direction of the outboard motor at the rear of the outer unit, and the lower end portion of the exhaust pipe that forms the exhaust passage is vertically formed in the upstream drainage passage and the downstream drainage passage. A first passage portion that penetrates the first passage portion, a second passage portion that penetrates the engine support member in a vertical direction at a position facing the first passage portion, and a matching portion of the engine support member and the oil pan And a third passage portion extending substantially horizontally from a lower end of the second passage portion toward a predetermined drainage portion.

In the present invention, the water generated in the exhaust passage is drained by the drain passage from the upstream side and the downstream side of the catalyst. Exhaust gas in the exhaust passage upstream from the catalyst (unpurified exhaust gas) flows into the drain passage where the drain valve is provided, and is restricted from flowing downstream in the drain passage by this drain valve. The
Therefore, according to the present invention, it is possible to prevent exhaust condensed water and condensed water generated in the exhaust passage from coming into contact with the catalyst while restricting the discharge of unpurified exhaust gas.

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 the principal part of this invention. It is a bottom view of the principal part of this invention. It is the IV-IV sectional view taken on the line in FIG. It is the VV sectional view taken on the line in FIG. It is the VI-VI sectional view taken on the line in FIG. It is the VII-VII sectional view taken on the line in FIG. It is the VIII-VIII sectional view taken on the line in FIG. It is the side view seen from the outboard motor right side of the left exhaust pipe. It is the side view seen from the left side of the outboard motor of the right side exhaust pipe and the 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 of the outboard motor. It is a top view of the rear part of a guide exhaust, and an exhaust pipe. It is a rear view of a guide exhaust and a bottom view of an exhaust pipe. FIG. 6 is a side view of the exhaust pipe, the guide exhaust, and the rear of the upper casing as viewed from the left side of the outboard motor. In the figure, the air-fuel ratio sensor portion is shown in a cutaway manner. It is the sectional view on the AA line in FIG. In the drawing, the breaking position of the upper end portion of the guide exhaust is changed so that the hose joint is broken. It is the BB sectional view taken on the line in FIG. It is CC sectional view taken on the line in FIG. It is sectional drawing which expands and shows a part of FIG. It is the side view seen from the outboard motor right side of the left exhaust pipe. It is the DD sectional view taken on the line in FIG. It is a figure which shows the other example of the 2nd waste_water | drain part, The figure is a bottom part of the rear part of a guide exhaust, and an exhaust pipe. It is a cross-sectional view of a guide exhaust and an exhaust pipe member. It is the EE sectional view taken on the line in FIG. It is the FF sectional view taken on the line in FIG.

(First embodiment)
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. In this embodiment, the engine support member according to the second aspect of the present invention is constituted by the guide exhaust 2.
A left side passage hole 2a constituting a part of the upstream side exhaust passage 9 referred to in the invention of claim 2 is formed on one side of the guide exhaust 2 on the left side of the outboard motor (see FIG. 5). 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 invention described in claim 2, and opens on the right side surface of the guide exhaust 2 as an exhaust inlet 16 and on the lower surface of the guide exhaust 2. It is open.

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 invention according to claim 2, wherein the internal space of the right passage hole 2 b 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 are used. A downstream exhaust passage 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.

The exhaust pipe 13 is for forming a catalyst exhaust passage 24 (see FIGS. 1 to 3) in the vicinity of the engine so that the exhaust gas flows in a substantially horizontal direction. As shown in FIGS. 2 and 3, the exhaust pipe 13 includes a left exhaust pipe 31 that extends from one side of the left side of the outboard motor of the guide exhaust 2 to the rear side 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.
The exhaust pipe main body 35 according to this embodiment is formed so that water can flow in the exhaust passage 41 from the upstream end toward the catalyst 34.

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 water chamber 23 of the upper casing 4 by a cooling water hose (not shown).

  As shown in FIG. 6, an upstream drainage passage 54 is formed at the lower end of the left catalyst housing half 36 to discharge water generated in the exhaust passage 41 upstream from the catalyst 34. 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.

One end (upstream end) of the upstream drainage passage 54 opens into the exhaust passage 41, extends downward from the lower end of the left catalyst housing half 36, and extends to the left side of the outboard motor. Is formed. The other end of the upstream drainage passage 54 opens to the left side surface of the left catalyst housing half 36.
An annular space S1 is formed between the left catalyst housing half 36 and the cylinder 47 of the catalyst 34 so that the exhaust condensed water, condensed water, and the like can flow in. The upstream end of the upstream drainage 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 condensed water collected in the left exhaust pipe 31 toward the catalyst 34 are discharged from the space S <b> 1 into the upstream drainage passage 54 without contacting the catalyst 34.

  The other end of the upstream drainage passage 54 is connected to, for example, the water chamber 23 of the upper casing 4 via a drainage valve 55 formed of a float type on-off valve and a hose (not shown). As shown in FIG. 7, the drain 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 drain 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 drain valve 55 is provided in the upstream drain passage 54 in this way is to prevent exhaust gas from being discharged from the upstream side of the catalyst 34 through the upstream drain passage 54. In this embodiment, the drain valve 55 constitutes a drain valve in the present invention.

  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 so that the exhaust condensed water, condensed water, and the like can flow in.
Further, as shown in FIGS. 4 and 6, a downstream drainage passage for discharging exhaust condensed water or dew condensation water from an exhaust passage 51 on the downstream side of the catalyst 34 is provided at the lower end of the right catalyst housing half 81. 86 is connected. The downstream drainage passage 86 is formed by a drainage hole 86 a drilled in the right catalyst housing half 81, an exhaust passage of the idle muffler 52 provided below the catalyst 34, and the like.

  The drain hole 86a opens to the space S2 and the upper end portion of the right idle muffler half 62 of the idle muffler 52, and the exhaust passage 51 on the downstream side of the catalyst 34 and the right idle muffler half 62 inside. Is communicated. That is, one end (upstream end) of the downstream drainage passage 86 opens into the exhaust passage 51 downstream from the catalyst 34. Further, the exhaust condensed water and condensed water collected in the right exhaust pipe 32 toward the catalyst 34 are discharged from the space S <b> 2 into the downstream drainage passage 86 without contacting the catalyst 34.

  The water flowing down from the drain hole 86a into the right idle muffler half 62 has 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 a 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 86a → 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 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 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. The exhaust pipe body 105 according to this embodiment is formed so that water can flow in the exhaust passage 108 from the downstream end toward the catalyst 34. In this embodiment, the exhaust passage for catalyst 24 is constituted by the exhaust passage 108, the exhaust passage 51 in the communication pipe 33, and the exhaust passage 41 in the left exhaust pipe 31.

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.

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 an expansion / contraction portion 112 of the exhaust pipe 13.

  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 water chamber 23 of the upper casing 4 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.

  In the exhaust device 7 of the outboard motor 1 configured as described above, the upstream drainage passage 54 having one end opened on the upstream side of the catalyst 34 in the catalyst exhaust passage 24 and the downstream side of the catalyst 34 in the catalyst exhaust passage 24. A downstream drainage passage 86 (a drainage hole 86a and an exhaust passage in the idle muffler 52) having one end opened on the side is provided. Further, the upstream drainage passage 54 is provided with a drainage valve 55 that can regulate the outflow of exhaust gas and discharge only water in the exhaust passage.

For this reason, according to the exhaust device 7 of this embodiment, the exhaust condensed water and dew condensation water generated in the catalyst exhaust passage 24 are discharged from the upstream side and the downstream side of the catalyst 34 to the upstream side drain passage 54 and the downstream side drainage. It is drained by a passage 86. On the other hand, the exhaust gas (unpurified exhaust gas) in the exhaust passage 41 upstream from the catalyst 34 flows into the upstream drain passage 54 to the drain valve 55, and the drain valve 55 causes the upstream drain passage 54 to move downstream. It is restricted from flowing.
Therefore, according to this embodiment, it is possible to prevent exhaust condensed water and condensed water generated in the exhaust passage from coming into contact with the catalyst 34 while restricting discharge of unpurified exhaust gas.

The catalyst exhaust passage 24 according to this embodiment is formed so that water can flow from the upstream end connected to the exhaust outlet 12 of the guide exhaust 2 toward the catalyst 34, and is connected to the exhaust inlet 16 of the guide exhaust 2. Water is formed to flow from the downstream end toward the catalyst. A space S1 into which water can flow is formed between the inner wall surface of the exhaust passage 41 upstream of the catalyst 34 and the catalyst 34, and the inner wall surface of the exhaust passage 51 downstream of the catalyst 34 and the catalyst 34. A space S2 into which water can flow is formed between the two. The upstream drainage passage 54 opens into the space S1, and the downstream drainage passage 86 opens into the space S2.
For this reason, while preventing the water in the catalyst exhaust passage 24 from coming into contact with the catalyst 34, the water can be smoothly flowed to the drain passage, and the water stays unnecessarily in the catalyst exhaust passage 24. Can be prevented.

  If there is a raised portion in the catalyst exhaust passage 24 where a part of the passage wall is partially raised, water is blocked by the raised portion and stored, and this water is pushed by the exhaust gas at a time. There is a risk of flowing into the catalyst 34. However, according to the exhaust device 7 of this embodiment, the water in the catalyst exhaust passage 24 can be discharged from the upstream drainage passage 54 and the downstream drainage passage 86 without stagnation in the middle. Is even less likely to come into contact.

In this embodiment, an idle muffler 52 that exhausts exhaust gas during idling is provided below the catalyst exhaust passage 24. A downstream drainage passage 86 connected to the exhaust passage 51 downstream from the catalyst 34 is formed using the exhaust passage of the idle muffler 52.
For this reason, according to this embodiment, since it is not necessary to form a passage that exclusively functions as the downstream drainage passage 86, the exhaust device 7 can be reduced in size and cost.

  The idle muffler 52 according to this embodiment is formed integrally with the left exhaust pipe 31 and the communication pipe 33 having the catalyst exhaust passage 24. Therefore, the idle muffler 52 can be provided in the vicinity of the catalyst exhaust passage 24 in a compact manner.

(Second embodiment)
The exhaust device for an outboard motor according to the present invention can be configured as shown in FIGS. In these drawings, members that are the same as or equivalent to those described with reference to FIGS. 1 to 13 are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

  As shown in FIG. 14, the catalyst exhaust passage 24 according to this embodiment places the guide exhaust 2 in the width direction of the outboard motor 1 behind the outboard motor 1 from the exhaust outlet 12 and the exhaust inlet 16 of the guide exhaust 2. It is formed to penetrate. That is, as shown in FIG. 14 and FIG. 17, a through hole 201 having a circular cross section is formed at the rear end of the guide exhaust 2 according to this embodiment, and the left exhaust pipe 202 and the right exhaust pipe 203 are on the side. Is inserted from the side.

The left exhaust pipe 202 and the right exhaust pipe 203 are formed so as to be symmetric in the width direction of the outboard motor 1.
As shown in FIGS. 14, 16, 21, and 22, the left exhaust pipe 202 is formed around an exhaust pipe body 204 that extends in the front-rear direction of the outboard motor 1 and the exhaust pipe body 204. The mounting flange 205 and a left catalyst housing half 206 provided at the rear end of the exhaust pipe body 204 are configured.

  As shown in FIG. 14, the right exhaust pipe 203 includes an exhaust pipe main body 210 extending in the front-rear direction of the outboard motor 1, a mounting flange 211 formed around the exhaust pipe main body 210, and the exhaust pipe. And a right catalyst housing half 212 provided at the rear end of the main body 210. In each of these exhaust pipes 202 and 203, the exhaust pipe main bodies 204 and 210, the mounting flanges 205 and 211, and the catalyst housing halves 206 and 212 are integrally formed by casting.

  Further, the exhaust pipe main body 204 of the left exhaust pipe 202 and the exhaust pipe main body 210 of the right exhaust pipe 203 are arranged such that water passes through the exhaust passages 213 and 214 formed inside these members from the front end portion to the rear end portion. It is formed so that it can flow toward (catalyst 34). Cooling water passages 215 and 216 are formed in the exhaust pipe main body 204 and the exhaust pipe main body 210 so as to surround the exhaust passages 213 and 214. These cooling water passages 215 and 216 communicate with the cooling water passage 43 in the guide exhaust 2.

  The mounting flanges 205 and 211 are fixed to the guide exhaust 2 by fixing bolts 217 in a state where the mounting flanges 205 and 211 are overlapped on the side surface of the guide exhaust 2. The left exhaust pipe 202 and the right exhaust pipe 203 are guided exhaust by mounting flanges 205 and 211 in a state in which a left catalyst housing half 206 and a right catalyst housing half 212 to be described later are inserted into the through holes 201, respectively. 2 is attached.

  The mounting flanges 205 and 211 are formed so as to block the opening of the through hole 201 of the guide exhaust 2 from the side. In this way, the through-hole 201 is closed by the mounting flanges 205 and 211, whereby the cooling water communicated with the cooling water passages 215 and 216 between the hole wall surface of the through-hole 201 and the left and right exhaust pipes 202 and 203. Water passages 218 and 219 (see FIG. 19) are formed. These cooling water passages 218 and 219 are communicated with each other by a cooling water hose 220 (see FIGS. 4 and 19) connected to the upper end of the guide exhaust 2.

  In this embodiment, as shown in FIGS. 20 and 21, there is a reinforcement between the mounting flanges 205 and 211 and the portions of the left and right exhaust pipes 202 and 203 that are inserted into the through holes 201. Ribs 221 are provided. Further, as shown in FIGS. 14 and 16, hose joints 223 and 224 are attached to the lower ends of the attachment flanges 205 and 211 in order to discharge the cooling water in the left exhaust pipe 202 and the right exhaust pipe 203. It has been. Further, as shown in FIGS. 14 and 16, a hose joint 225 is attached to the upper end portion of the guide exhaust 2 on the left side of the outboard motor in order to discharge bubbles from the cooling water passages 215, 216, 218, and 219. ing.

  The left catalyst housing half 206 and the right catalyst housing half 212 are inserted into the through hole 201 of the guide exhaust 2 and hold the catalyst 34 in the through hole 201 as shown in FIG. More specifically, the left catalyst housing half 206 and the right catalyst housing half 212 are each formed in a cylindrical shape that fits into the through hole 201. Further, the left catalyst housing half 206 and the right catalyst housing half 212 receive the cylinder 47 of the catalyst 34 from one side and the other side in the width direction of the outboard motor 1 and also have a fixing flange 48 of the catalyst 34. It is pinched.

Between the left catalyst housing half 206 and the right catalyst housing half 212 and the hole wall surface of the through hole 201, leakage of the cooling water from the cooling water passages 218 and 219, and in the left and right exhaust pipes 202 and 203, O-rings 226 are provided to prevent leakage of exhaust gas from the catalyst exhaust passage 24.
Further, as shown in FIGS. 20 and 21, a metal O-ring 227 described later is provided between the left catalyst housing half 206 and the right catalyst housing half 212 and the fixing flange 48.

  The metal O-ring 227 is an annular metal pipe, and is formed so as to have elasticity even when heat of exhaust gas is applied. As shown in FIG. 22, the metal O-ring 227 is attached to the outer peripheral portions of the two halves 206 and 212. As shown in FIG. 20, the left catalyst housing half 206 and the right catalyst housing half 212 are metal O-rings when the guide exhaust 2 and the left and right exhaust pipes 202 and 203 are not expanded by heat. It is formed so as to come into contact with the fixing flange 48 of the catalyst 34 through 227.

  In the cold state, as shown in FIG. 20, a gap d1 is formed between the left catalyst housing half 206 and the fixing flange 48, and between the right catalyst housing half 212 and the fixing flange 48. A gap d2 is formed. Since the gaps d1 and d2 are formed in this way, and the metal O-ring 227 is formed so as to be elastically deformable, the left catalyst housing half 206 and the right catalyst housing half 212 have one of them. On the other hand, the other can move in the width direction of the outboard motor 1. Therefore, if there is a difference between the thermal expansion amount of the guide exhaust 2 and the thermal expansion amounts of the left exhaust pipe 202 and the right exhaust pipe 203, the left exhaust pipe 202 and the right exhaust pipe 203 are connected to each other. Displaces to follow.

As shown in FIG. 19, an upstream drain passage 231 is connected to the lower end of the left catalyst housing half 206, and a downstream drain passage 232 is connected to the lower end of the right catalyst housing half 212. .
Although the details will be described later, the upstream drainage passage 231 is a rear first drainage portion for explaining exhaust condensed water and dew condensation water from a portion upstream of the catalyst 34 in the catalyst exhaust passage 24 (the exhaust passage 213). 233 (see FIG. 15). The first drainage unit 233 is configured by an idle muffler 52 described later.

  The downstream drainage passage 232, which will be described in detail later, allows exhaust condensed water and dew condensation water to flow forward from the second drainage portion 234 from the portion of the catalyst exhaust passage 24 downstream of the catalyst 34 (the exhaust passage 214). (See FIG. 15). The second drainage portion 234 is a portion that is open on the lower surface of the guide exhaust 2 in the downstream exhaust passage 15.

  The upstream drainage passage 231 and the downstream drainage passage 232 are first passage portions 235 and 236 having through holes penetrating the left catalyst housing half 206 and the right catalyst housing half 212 in the vertical direction (FIG. 19, FIG. 19). 20), second passage portions 237 and 238 each having a through-hole penetrating the guide exhaust 2 in the vertical direction at positions opposed to the first passage portions 235 and 236, the guide exhaust 2 and the oil pan 17 And a third passage portion 240 extending from the lower end openings of the second passage portions 237 and 238 toward the first and second drainage portions 233 and 234 in the mating portion 239 (see FIG. 17). 241 (see FIGS. 15, 17, and 18).

As shown in FIG. 19, the first passage portions 235 and 236 and the second passage portions 237 and 238 are disposed in a portion surrounded by the two O-rings 226 and 226. For this reason, the cooling water does not leak into the upstream drainage passage 231 and the downstream drainage passage 232. The upper end of the first passage portion 235 opens into the space S1, and the upper end of the first passage portion 236 opens into the space S2. For this reason, also in this embodiment, exhaust condensed water and condensed water can be discharged so as not to contact the catalyst 34.
As shown in FIGS. 15 and 17, the third passage portions 240 and 241 are provided with concave grooves 240a and 241a formed on the lower surface of the guide exhaust 2, and the upper surface of the oil pan 17 facing the concave grooves 240a and 241a. 17a.

  As shown in FIG. 15, the third passage portion 240 of the upstream drainage passage 231 extends diagonally to the left of the outboard motor 1 from the opening at the lower end of the second passage portion 237 (lower rightward in FIG. 15). It is formed so as to extend, and is connected to a fourth passage portion 242 described later. The fourth passage portion 242 extends from the rear end portion of the third passage portion 240 to the left side of the outboard motor (right side in FIG. 15) and penetrates the guide exhaust 2 and the left exhaust pipe 202. Is formed by.

The fourth passage portion 242 is connected to the idle muffler 52 via a drain valve 55 attached to the left exhaust pipe 202 and a hose 243 connected to a drain joint 55a of the drain valve 55. For this reason, the exhaust gas flowing into the upstream drainage passage 231 from the exhaust passage 213 on the upstream side of the catalyst is restricted by the drainage valve 55 from flowing downstream.
As shown in FIG. 17, the idle muffler 52 according to this embodiment includes an upper half 251 formed at the rear end of the guide exhaust 2, a lower half 252 formed at the upper end of the upper casing 4, It is comprised by the partition plate 253 etc. which were provided inside the both half parts 251 and 252.

  As shown in FIG. 15, the idle muffler 52 includes an idle exhaust passage 254 formed so as to extend in the front-rear direction between the lower surface of the guide exhaust 2 and the upper casing 4. The exhaust gas is led from. Further, the exhaust gas in the idle muffler 52 is discharged out of the outboard motor 1 through a discharge pipe 255 protruding rearward from the upper half 251.

  A drainage joint 256 for discharging water introduced by the hose 243 is attached to the lower end portion of the idle muffler 52. For this reason, the upstream drainage passage 231 according to this embodiment is formed by using the exhaust passage in the idle muffler 52.

  As shown in FIG. 15, the third passage portion 241 of the downstream drainage passage 232 is obliquely forward (rightward of the outboard motor 1 from the lower end opening of the second passage portion 238 toward the downstream exhaust passage 15. In FIG. 15, it extends in the upper left direction. For this reason, the exhaust condensed water and the condensed water in the exhaust passage 214 on the downstream side of the catalyst flow through the downstream drain passage 232 and are discharged into the downstream exhaust passage 15.

Even if the upstream drainage passage 231 and the downstream drainage passage 232 are formed as shown in this embodiment, the same effect as the first embodiment can be obtained.
In particular, in this embodiment, the upstream drainage passage 231 and the downstream drainage passage 232 are formed by the left and right exhaust pipes 202 and 203, the guide exhaust 2 and the oil pan 17. A drainage structure for discharging water can be formed compactly.

In the examples shown in FIGS. 14 to 22, an example in which exhaust condensed water and condensed water on the downstream side of the catalyst are discharged to the downstream side exhaust passage 15 is shown. It can be discharged from the side of the right exhaust pipe.
FIG. 23 is a diagram showing other examples of drainage passages. In these drawings, the same or equivalent members as those described with reference to FIGS. 14 to 22 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate. To do.

  The downstream drainage passage 232 shown in FIG. 23 is formed so as to guide exhaust condensed water and dew condensation water to a second drainage part 234 located behind the right side of the outboard motor (left side in FIG. 23). Specifically, the third passage portion 241 of the downstream drainage passage 232 is formed so as to extend diagonally to the right rear of the outboard motor from the opening at the lower end of the second passage portion 238. A fourth passage portion 261 extending in the width direction of the outboard motor 1 is connected to the rear end portion of the third passage portion 241.

  The fourth passage portion 261 communicates the third passage portion 241 and the hose joint 262 attached to the right exhaust pipe 203. The hose joint 262 is connected to, for example, the water chamber 23 in the upper casing 4 via a hose (not shown). Even if the downstream drainage passage 232 is configured in this manner, the same effects as those of the embodiment shown in FIGS.

(Third embodiment)
The exhaust device for an outboard motor according to the present invention can be configured as shown in FIGS. In these drawings, members that are the same as or equivalent to those described with reference to FIGS. 1 to 13 are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

  The exhaust outlet 12 and the exhaust inlet 16 of the guide exhaust 2 shown in FIG. 24 are open on the rear surface 301 of the guide exhaust 2. In FIG. 24, the front of the outboard motor 1 is indicated by an arrow F. The catalyst exhaust passage 24 according to this embodiment includes an exhaust passage forming member 303 fixed to a rear end portion of the guide exhaust 2 by a fixing bolt 302 and a fixing bolt 304 attached to a rear end portion of the exhaust passage forming member 303. A fixed left catalyst housing half 305 and a right catalyst housing half 306 are formed. The catalyst 34 according to this embodiment is accommodated in the left catalyst housing half 305 and the right catalyst housing half 306.

  The exhaust passage forming member 303 includes a left exhaust passage 308 that communicates the exhaust outlet 12 and an exhaust passage 307 in a left catalyst housing half 305 to be described later, and a right catalyst housing half 306 to be described later and the exhaust inlet 16. A right exhaust passage 310 communicating with the inner exhaust passage 309 and an air passage 311 for introducing outside air into the right exhaust passage 310 are formed.

  The left exhaust passage 308 and the exhaust passage 307 in the left catalyst housing half 305 are formed so that water can flow from the upstream end (the exhaust outlet 12) to the catalyst 34. The right exhaust passage 310 and the exhaust passage 309 in the right catalyst housing half 306 are formed so that water can flow from the downstream end (the exhaust inlet 16) to the catalyst 34.

  As shown in FIGS. 25 and 26, the air passage 311 is communicated with the atmosphere via a reed valve 312. The reed valve 312 is configured to open when the pressure in the air passage 311 (exhaust passage 310) becomes negative, and the outside air is sucked into the air passage 311. By providing the reed valve 312 as described above, the reed valve is provided when the pressure in the exhaust passage 310 (the entire area from the upstream exhaust passage 9 through the catalyst exhaust passage 24 to the downstream exhaust passage 15) becomes negative. Since outside air is introduced into the exhaust passage from 312, it is possible to prevent water from rising from the propeller portion in the exhaust passage due to the negative pressure.

  The left catalyst housing half 305 and the right catalyst housing half 306 are configured to receive the cylinder 47 of the catalyst 34 and sandwich the fixing flange 48 from one side and the other side in the width direction of the outboard motor 1. ing. The left catalyst housing half 305 and the right catalyst housing half 306 are fastened to each other by a connecting bolt 313 that passes through the fixing flange 48, and the exhaust passage is formed in such an integrated state. It is attached to the member 303.

  Cooling water passages 314 and 315 are formed in the left catalyst housing half 305 and the right catalyst housing half 306 so as to surround the exhaust passages 307 and 309. These cooling water passages 314 and 315 communicate with each other by a communication passage (not shown) formed so as to pass through the fixing flange 48 of the catalyst 34 and are formed in the exhaust passage forming member 303. The cooling water passages 316 and 317 communicate with each other. These cooling water passages 316 and 317 are formed so as to surround the exhaust passages 308 and 310, and communicate a cooling water passage (not shown) in the guide exhaust 2 with the cooling water passages 314 and 315. ing.

  An upstream drainage passage 321 is connected to the lower end of the left catalyst housing half 305 as shown in FIG. 25, and a downstream drainage is connected to the lower end of the right catalyst housing half 306 as shown in FIG. A passage 322 is connected. These drain passages 321 and 322 are formed using an idle muffler 52 provided below the catalyst 34.

  The idle muffler 52 according to this embodiment includes a lid member 331 attached to the left catalyst housing half 305 and the right catalyst housing half 306 from below, and a muffler body in which an opening at the upper end is closed by the lid member 331 332, a partition plate 333 sandwiched between the lid member 331 and the muffler main body 332, and an expansion chamber forming partition wall 334 provided on the lid member 331 and the muffler main body 332. The lower end portion of the muffler main body 332 is attached to the upper casing 4 by mounting bolts 335 as shown in FIGS. 25 and 26.

  The partition plate 333 partitions the inside of the idle muffler 52 in the vertical direction. The partition wall 334 includes an upper part 334 a formed integrally with the lid member 331 and a lower part 334 b formed integrally with the muffler main body 332, and partitions the inside of the idle muffler 52 in the front-rear direction of the outboard motor 1. ing.

  At the upper end of the lid member 331, a left connection pipe 336 (see FIG. 25) inserted into the left catalyst housing half 305 from below and a right connection pipe 337 inserted into the right catalyst housing half 306 from below. And are provided. The left connection pipe 336 is connected to the exhaust passage 307, that is, the upstream side of the catalyst 34 in the catalyst exhaust passage 24. The right connection pipe 337 is connected to the exhaust passage 309, that is, the downstream side of the catalyst 34 in the catalyst exhaust passage 24.

  As shown in FIG. 25, a drain chamber 341 is formed below the left connection pipe 336 in order to temporarily store exhaust condensed water and condensed water in the exhaust passage 307 upstream of the catalyst 34. . The drainage chamber 341 is formed so as to communicate with other parts in the idle muffler 52 by a drainage port 342 located at the lower end thereof. The drain port 342 is opened and closed by a drain valve 55 provided in the drain chamber 341.

  That is, when the water is stored in the drain chamber 341 and the float 59 of the drain valve 55 is moved upward, only the water flows downward from the drain port 342. As indicated by arrows in FIG. 25, this water passes through the communication hole 343 of the partition wall 334 and flows down to the bottom of the idle muffler 52, and from the drainage joint 344 attached to the bottom, the idle muffler 52 Is discharged outside.

  As shown in FIG. 26, the right connection pipe 337 communicates the exhaust passage 309 and the front expansion chamber 345 in the lid member 331. A part of the exhaust gas purified by the catalyst 34 flows into the front expansion chamber 345 from the right connection pipe 337, and is expanded and contracted in the idle muffler 52 from there to be decompressed, and then the exhaust pipe 346. (Refer to FIG. 24) and discharged to the rear of the idle muffler 52.

  On the other hand, the exhaust condensed water and dew condensation water in the exhaust passage 309 downstream of the catalyst 34 flows into the front expansion chamber 345 through the right connection pipe 337, as indicated by arrows in FIG. It flows down to the bottom in the idle muffler 52 through the communication hole 347 of the partition plate 333 and the communication hole 348 of the partition wall 334. Then, this water is discharged from the bottom of the idle muffler 52 to the outside of the idle muffler 52 by the drainage joint 344. That is, in this embodiment, both the water in the exhaust passage 307 on the upstream side of the catalyst and the water in the exhaust passage 309 on the downstream side of the catalyst are discharged through the inside of the idle muffler 52.

  The upper end of the left connection pipe 336 opens into a space S <b> 1 between the catalyst 34 and the left catalyst housing half 305. The upper end of the right connection pipe 337 opens into a space S <b> 2 between the catalyst 34 and the right catalyst housing half 306. For this reason, also in this embodiment, exhaust condensed water and condensed water can be discharged so as not to contact the catalyst 34.

Even if the exhaust device 7 is configured as shown in this embodiment, the same effects as in the first embodiment can be obtained.
In particular, in this embodiment, the drain valve 55 is accommodated in the idle muffler 52. For this reason, according to this embodiment, the exhaust device 7 can be downsized as compared with the case where the drain valve 55 is disposed outside the idle muffler 52.

DESCRIPTION OF SYMBOLS 1 ... Outboard motor, 2 ... Guide exhaust, 7 ... Exhaust device, 12 ... Exhaust outlet, 16 ... Exhaust inlet, 17 ... Oil pan, 24 ... Exhaust passage for catalyst, 34 ... Catalyst, 36 ... Half part of left catalyst housing, 52 ... Idle muffler, 54, 231, 321 ... Upstream drain passage, 55 ... Drain valve, 86, 232, 322 ... Downstream drain passage, 81 ... Right catalyst housing half, 235, 236 ... First passage, 237, 238 ... second passage part, 240, 241 ... third passage part.

Claims (6)

In an exhaust system for an outboard motor comprising a catalyst exhaust passage formed in the vicinity of the engine so that the exhaust gas flows in a substantially horizontal direction, and a catalyst provided in the catalyst exhaust passage,
An upstream drainage passage having one end opened to the exhaust passage upstream of the catalyst;
A downstream drainage passage having one end opened in the exhaust passage downstream of the catalyst;
An exhaust device for an outboard motor, wherein the upstream drainage passage is provided with a drainage valve that regulates the outflow of exhaust gas and can discharge only water in the exhaust passage. The outboard motor exhaust system according to claim 1, wherein the engine is supported by an engine support member,
The engine support member is formed with an exhaust outlet of an upstream exhaust passage extending downward from the engine and an exhaust inlet of a downstream exhaust passage extending downward from the engine support member,
An upstream end of the catalyst exhaust passage is connected to the exhaust outlet,
A downstream end of the catalyst exhaust passage is connected to the exhaust inlet;
The catalyst exhaust passage is formed such that water can flow from the upstream end toward the catalyst, and water can flow from the downstream end toward the catalyst.
A space into which the water can flow is formed between the inner wall surface of the catalyst exhaust passage and the catalyst,
The upstream drainage passage and the downstream drainage passage are exhaust devices for outboard motors that open into the space. The exhaust system for an outboard motor according to claim 1 or 2, wherein an idle muffler that exhausts exhaust gas during idling is provided below the catalyst exhaust passage.
The downstream drainage passage is an outboard motor exhaust device formed using an exhaust passage of the idle muffler.   4. The outboard motor exhaust apparatus according to claim 3, wherein an idle muffler is formed integrally with an exhaust pipe having the catalyst exhaust passage.   4. The outboard motor exhaust system according to claim 3, wherein the idle muffler houses the drain valve. The outboard motor exhaust system according to claim 2, wherein an oil pan is attached to a lower end portion of the engine support member,
The catalyst exhaust passage is formed so as to penetrate the engine support member in the width direction of the outboard motor behind the outboard motor from the exhaust outlet and the exhaust inlet.
The upstream drainage passage and the downstream drainage passage are a first passage portion that vertically penetrates a lower end portion of an exhaust pipe forming the exhaust passage,
A second passage portion that vertically penetrates the engine support member at a position facing the first passage portion;
Outboards each having a third passage portion extending substantially horizontally from a lower end of the second passage portion toward a predetermined drainage portion in a joint portion between the engine support member and the oil pan. Machine exhaust system.

Images