JP2010248910A - 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 to form a catalyst exhaust passage extending from one side to the other side of a guide exhaust 2, and a catalyst 33 provided in the exhaust pipe, the guide exhaust 2 having a through-hole 30 at the rear end. The exhaust pipe is composed of an upstream side exhaust pipe 31 extending from the exhaust outlet of the guide exhaust 2 to the through-hole 30, and a downstream side exhaust pipe 32 extending from the exhaust inlet of the guide exhaust 2 to the through-hole 30. The downstream side end of the upstream side exhaust pipe 31 is fitted to the upstream side end of the downstream side exhaust pipe 32 movably in the through-hole 30. A metal O-ring 63 is held between the downstream side end and the upstream side end. <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 outboard motor exhaust system comprising an exhaust pipe forming a passage and a catalyst provided in the exhaust pipe, an outboard motor main body is provided at one end of the outboard motor in the front-rear direction of the outboard motor. Forming a through-hole penetrating in the width direction of the outboard motor, the exhaust pipe extending from the exhaust outlet to the through-hole at one side in the width direction of the outboard motor; A downstream exhaust pipe extending from the exhaust inlet to the through hole at the other side in the width direction of the machine; Therefore, the downstream end portion of the upstream exhaust pipe and the upstream end portion of the downstream exhaust pipe are movably fitted into the through holes in a state where the outflow of exhaust gas is regulated. And an elastic member is sandwiched between the downstream end and the upstream end.

  The invention described in claim 2 is the outboard motor exhaust system according to claim 1, wherein the catalyst includes a downstream end of the upstream exhaust pipe, an upstream end of the downstream exhaust pipe, and A catalyst main body housed in the inside of the gas generator, and a fixing flange positioned between the upstream end and the downstream end, and the elastic member is connected to the downstream end of the upstream exhaust pipe and the It is provided between the flange and between the upstream end of the downstream exhaust pipe and the flange.

  According to a third aspect of the present invention, in the exhaust system for an outboard motor according to the first or second aspect, the elastic member comprises an annular metal pipe, and the downstream end of the upstream exhaust pipe It functions as a seal member for preventing leakage of exhaust gas between the upstream end of the downstream exhaust pipe.

  According to a fourth aspect of the present invention, there is provided the outboard motor exhaust device according to any one of the first to third aspects, wherein the upstream side exhaust pipe and the downstream side exhaust pipe are provided with openings of the through holes. And a cooling water passage is formed between the hole wall surface of the through hole and the upstream side exhaust pipe and the downstream side exhaust pipe.

According to the present invention, since the elastic member is sandwiched between the upstream side exhaust pipe and the downstream side exhaust pipe, one of the upstream side exhaust pipe and the downstream side exhaust pipe is connected to the other side of the outboard motor. It can move in the width direction of the outboard motor. Therefore, if there is a difference between the thermal expansion amount of the outboard motor main body and the thermal expansion amounts of the upstream exhaust pipe and the downstream exhaust pipe, the upstream exhaust pipe and the downstream exhaust pipe are connected to each other. Displace to follow thermal expansion.
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 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 VV sectional view taken on the line in FIG. It is the VI-VI sectional view taken on the 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 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 sectional drawing which expands and shows a part of FIG. It is the side view seen from the outboard motor right side of an upstream side exhaust pipe. It is the XI-XI sectional view taken on the line in FIG. It is a rear view of a guide exhaust and a bottom view of an exhaust pipe.

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 3, 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. Exhaust gas discharged from the exhaust outlet 12 flows into a catalyst exhaust passage 14 formed by an exhaust pipe 13 (see FIGS. 2 and 3), which will be described later, outside the guide exhaust 2. It is guided to the opposite side (outboard motor right side) of the outer motor 1 in the width direction.

  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 FIG. 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.
An opening at the upper end of the oil reservoir 18 communicates with 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 FIG. 6, a through hole 30 having a circular cross section is formed at the rear end of the guide exhaust 2. As shown in FIG. 7, the through hole 30 is formed so as to penetrate the guide exhaust 2 in the width direction of the outboard motor 1 (left and right direction in FIG. 7).

  As shown in FIGS. 2 and 3, the exhaust pipe 13 includes an upstream exhaust pipe 31 that extends from the exhaust outlet 12 to the through hole 30 at one side (left side) in the width direction of the outboard motor 1. And a downstream side exhaust pipe 32 extending from the exhaust inlet 16 to the through hole 30 on the other side (right side) in the width direction of the outboard motor 1. The downstream end of the upstream exhaust pipe 31 and the upstream half of the downstream exhaust pipe 32 are respectively inserted into the through holes 30 from the side. The exhaust pipe 13 according to this embodiment holds a catalytic converter 33 (hereinafter simply referred to as a catalyst) at a connection portion between the upstream side exhaust pipe 31 and the downstream side exhaust pipe 32.

Although the catalyst 33 used in this embodiment is not shown in detail, it is called a so-called metal catalyst, and a stainless steel plate carrier 34 wound in a spiral shape (see FIG. 8). And a cylinder 35 into which the plate-like carrier 34 is inserted, a fixing flange 36 welded to the central portion in the axial direction of the outer peripheral portion of the cylinder 35, and the like.
The outer shape of the plate-like carrier 34 is formed to be a perfect circle when viewed from the direction in which the exhaust gas flows, so that the spiral winding operation can be simplified and easily manufactured.

The upstream exhaust pipe 31 and the downstream exhaust pipe 32 are formed so as to be symmetric in the width direction of the outboard motor 1.
As shown in FIGS. 2, 4, 10, and 11, the upstream side exhaust pipe 31 is formed around an exhaust pipe body 41 that extends in the front-rear direction of the outboard motor 1 and the exhaust pipe body 41. And an upstream side catalyst housing half 43 provided at the rear end of the exhaust pipe main body 41.

  As shown in FIG. 2, the downstream exhaust pipe 32 includes an exhaust pipe main body 44 extending in the front-rear direction of the outboard motor 1, a mounting flange 45 formed around the exhaust pipe main body 44, and the exhaust gas. The downstream catalyst housing half 46 is provided at the rear end of the pipe body 44. In each of these exhaust pipes 31 and 32, the exhaust pipe main bodies 41 and 44, the mounting flanges 42 and 45, and the catalyst housing halves 43 and 46 are integrally formed by casting.

  Further, the exhaust pipe main body 41 of the upstream side exhaust pipe 31 and the exhaust pipe main body 44 of the downstream side exhaust pipe 32 are arranged such that water passes through the exhaust passages 47 and 48 formed inside these members from the front end portion. It is formed so that it can flow to the end (catalyst 33). Cooling water passages 49 and 50 are formed in the exhaust pipe main body 41 and the exhaust pipe main body 44 so as to surround the exhaust passages 47 and 48. These cooling water passages 49 and 50 communicate with the cooling water passage 51 (see FIG. 5) in the guide exhaust 2.

As shown in FIGS. 2 and 4, an air-fuel ratio sensor 52 including an O ₂ sensor that detects the amount of oxygen in the exhaust gas upstream of the catalyst 33 is attached to the exhaust pipe body 41 of the upstream side exhaust pipe 31. Yes. The air-fuel ratio sensor 52 is positioned at the highest portion of the exhaust pipe main body 41. In this embodiment, an abnormality detection sensor 53 (see FIG. 2) for detecting abnormality of the air-fuel ratio sensor 52 and deterioration of the catalyst 33 is attached to the upper end portion of the other exhaust pipe main body 44. This abnormality detection sensor 53 is capable of detecting the amount of oxygen in the exhaust gas downstream of the catalyst 33. The detection of the abnormality is performed by comparing the sensor output on the upstream side of the catalyst 33 with the sensor output on the downstream side, as is well known.

  The mounting flanges 42 and 45 are fixed to the guide exhaust 2 by fixing bolts 54 in a state where the mounting flanges 42 and 45 are overlapped on the side surface of the guide exhaust 2. The upstream side exhaust pipe 31 and the downstream side exhaust pipe 32 are respectively connected to the mounting flange 42, with an upstream side catalyst housing half 43 and a downstream side catalyst housing half 46, which will be described later, inserted into the through hole 30, respectively. 45 is attached to the guide exhaust 2.

  The mounting flanges 42 and 45 are formed so as to block the opening of the through hole 30 of the guide exhaust 2 from the side. In this embodiment, the mounting flanges 42 and 45 constitute a lid as referred to in the invention of claim 4. In this way, the through hole 30 is closed by the mounting flanges 42 and 45, whereby the cooling water communicated with the cooling water passages 49 and 50 between the hole wall surface of the through hole 30 and the left and right exhaust pipes 31 and 32. Water passages 55 and 56 (see FIG. 8) are formed. These cooling water passages 55 and 56 are communicated with each other by a cooling water hose 57 (see FIGS. 4 and 8) connected to the upper end of the guide exhaust 2.

  In this embodiment, as shown in FIGS. 10 and 11, there is a reinforcement between the mounting flanges 42 and 45 and the portions of the left and right exhaust pipes 31 and 32 that are inserted into the through holes 30. Ribs 58 are provided. Further, as shown in FIGS. 2 and 4, hose joints 59, 60 are provided at the lower ends of the mounting flanges 42, 45 in order to discharge the cooling water in the upstream exhaust pipe 31 and the downstream exhaust pipe 32. Is installed. Further, as shown in FIGS. 2 and 4, a hose joint 61 is attached to the upper end portion of the guide exhaust 2 on the left side of the outboard motor in order to discharge air bubbles from the cooling water passages 49, 50, 55, and 56. ing.

  As shown in FIG. 8, the upstream catalyst housing half 43 and the downstream catalyst housing half 46 are inserted into the through hole 30 of the guide exhaust 2 and hold the catalyst 33 in the through hole 30. Yes. Specifically, the upstream catalyst housing half 43 and the downstream catalyst housing half 46 are each formed in a cylindrical shape that fits into the through hole 30. The upstream catalyst housing half 43 and the downstream catalyst housing half 46 accommodate the cylinder 35 of the catalyst 33 from one side and the other side in the width direction of the outboard motor 1, and a fixing flange for the catalyst 33. 36 is sandwiched.

Between the upstream catalyst housing half 43 and the downstream catalyst housing half 46 and the hole wall surface of the through hole 30, leakage of the cooling water from the cooling water passages 55, 56 and the left and right exhaust pipes 31, 32 are provided. An O-ring 62 is provided to prevent leakage of exhaust gas from the catalyst exhaust passage 14 therein.
Further, between the upstream catalyst housing half 43 and the downstream catalyst housing half 46 and the fixing flange 36, as shown in FIGS. 8 and 9, a metal O-ring constituting the elastic member referred to in the present invention. 63 is provided.

  The metal O-ring 63 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. 11, the metal O-ring 63 is mounted so as to be in contact with the outer peripheral portions of the half halves 43 and 46 over the entire circumference. That is, the metal O-ring 63 also functions as a seal member that prevents exhaust gas from leaking.

  As shown in FIG. 9, the upstream catalyst housing half 43 and the downstream catalyst housing half 46 are arranged in the cold state when the guide exhaust 2 and the left and right exhaust pipes 31 and 32 are not expanded by heat. , And are formed so as to come into contact with the fixing flange 36 of the catalyst 33 through the metal O-ring 63.

  As shown in FIG. 9, the metal O-ring 63 is pressed and compressed by the upstream catalyst housing half 43 and the downstream catalyst housing half 46 in the above-described state (cold state and assembled state). Yes. In addition, the metal O-ring 63 can be simply brought into contact with the upstream catalyst housing half 43, the downstream catalyst housing half 46, and the fixing flange 36 in the above-described state.

  In this embodiment, as shown in FIG. 9, a gap d1 is formed between the upstream catalyst housing half 43 and the fixing flange 36 when cold, and the downstream catalyst housing half 46 and the fixing flange 36 are formed. A gap d <b> 2 is formed between the gap 36. Since the gaps d1 and d2 are formed as described above, and the metal O-ring 63 is formed to be elastically deformable, the upstream catalyst housing half 43 and the downstream catalyst housing half 46 are separated from each other. The other can move in the width direction of the outboard motor 1.

  When the engine 3 is in operation, the guide exhaust 2, the upstream side exhaust pipe 31, and the downstream side exhaust pipe 32 are expanded by heat. The amount of thermal expansion of these members varies from member to member and hardly coincides. In this embodiment, one of the upstream catalyst housing half 43 and the downstream catalyst housing half 46 moves relative to the other, so that the difference in thermal expansion can be offset.

That is, according to this embodiment, the upstream catalyst housing half 43 and the downstream catalyst housing half 46 approach each other against the elastic force of the metal O-ring 63 or have been compressed. The upstream catalyst housing half 43 and the downstream catalyst housing half 46 can be separated from each other so that the elastic deformation of the O-ring 63 is eliminated.
For this reason, the upstream side exhaust pipe 31 and the downstream side exhaust pipe 32 can be displaced so as to follow the thermal expansion of the guide exhaust 2.

As shown in FIG. 8, an upstream drain passage 71 is connected to the lower end of the upstream catalyst housing half 43, and a downstream drain passage 72 is connected to the lower end of the downstream catalyst housing half 46. ing.
The upstream drainage passage 71, which will be described in detail later, is a first rear drainage portion that will later explain exhaust condensed water and dew condensation water from a portion upstream of the catalyst 33 (the exhaust passage 47) in the catalyst exhaust passage 14. 73 (see FIG. 3). The first drainage unit 73 is configured by an idle muffler 74 described later.

  In addition, the downstream drainage passage 72 will be described in detail later, but exhaust condensate water and dew condensation water from the portion downstream of the catalyst 33 (the exhaust passage 48) in the catalyst exhaust passage 14 is forwarded to the second drainage portion 75. (See FIG. 3). The second drainage portion 75 is a portion that is open to the lower surface of the guide exhaust 2 in the downstream exhaust passage 15.

  The upstream drainage passage 71 and the downstream drainage passage 72 are first passage portions 76 and 77 having through holes penetrating the upstream catalyst housing half 43 and the downstream catalyst housing half 46 in the vertical direction (see FIG. 8 and 9), second passage portions 78 and 79 each having a through-hole penetrating the guide exhaust 2 in the vertical direction at a position facing the first passage portions 76 and 77, the guide exhaust 2 and the oil. A third passage extending from the lower end opening of the second passage portions 78 and 79 toward the first and second drainage portions 73 and 75 in the mating portion 80 (see FIG. 6) with the pan 17 Parts 81 and 82 (see FIGS. 3, 6 and 7).

As shown in FIG. 8, the first passage portions 76 and 77 and the second passage portions 78 and 79 are disposed in a portion surrounded by the two O-rings 62 and 62. For this reason, the cooling water does not leak into the upstream drainage passage 71 and the downstream drainage passage 72.
As shown in FIGS. 3 and 6, the third passage portions 81 and 82 are recessed grooves 81 a and 82 a formed on the lower surface of the guide exhaust 2, and the upper surface of the oil pan 17 facing the recessed grooves 81 a and 82 a. 17a.

  As shown in FIG. 3, the third passage portion 81 of the upstream drainage passage 71 is located diagonally to the left of the outboard motor 1 from the opening at the lower end of the second passage portion 78 (downward rightward in FIG. 3). It is formed so as to extend, and is connected to a first passage portion 83 described later. The fourth passage portion 83 extends from the rear end portion of the third passage portion 81 to the left side of the outboard motor (the right side in FIG. 3) and penetrates the guide exhaust 2 and the upstream side exhaust pipe 31. It is formed by a hole.

The fourth passage portion 83 is connected to the idle muffler 74 via a drain valve 84 attached to the upstream side exhaust pipe 31 and a hose 85 connected to the drain joint 84a of the drain valve 84.
Although not shown, the drain valve 84 is a valve provided with a valve body that works in conjunction with the float, and is configured such that only water is discharged downstream while regulating the outflow of exhaust gas.
For this reason, the exhaust gas flowing into the upstream drainage passage 71 from the exhaust passage 47 on the upstream side of the catalyst is restricted by the drainage valve 84 from flowing downstream.

The idle muffler 74 emits exhaust gas when the engine 3 is in an idling operation state or a low speed operation state (when no exhaust pressure is generated so that water entering the exhaust passage 22 in the lower casing 5 can be discharged). The sound is silenced and discharged out of the outboard motor 1.
As shown in FIG. 6, the idle muffler 74 according to this embodiment includes an upper half portion 86 formed at the rear end portion of the guide exhaust 2, a lower half portion 87 formed at the upper end portion of the upper casing 4, It is constituted by a partition plate 88 provided inside both halves 86 and 87.

  As shown in FIG. 3, the idle muffler 74 includes an idle exhaust passage 89 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 74 is discharged out of the outboard motor 1 from a discharge pipe 90 protruding rearward from the upper half portion 86.

  As shown in FIG. 6, a drainage joint 91 for discharging water introduced by the hose 85 is attached to the lower end portion of the idle muffler 74. For this reason, the upstream drainage passage 71 according to this embodiment is formed using an exhaust passage in the idle muffler 74.

  As shown in FIG. 3, the third passage portion 82 of the downstream drainage passage 72 is obliquely forward (rightward and forward) of the outboard motor 1 from the lower end opening of the second passage portion 79 toward the downstream exhaust passage 15. In FIG. 3, it extends to the upper left). For this reason, the exhaust condensed water and the dew condensation water in the exhaust passage 48 on the downstream side of the catalyst flow through the downstream drain passage 72 and are discharged into the downstream exhaust passage 15.

According to the exhaust device 7 of the outboard motor 1 configured as described above, the elastically deformable metal O-ring 63 is sandwiched between the upstream side exhaust pipe 31 and the downstream side exhaust pipe 32, so that the upstream side One of the side exhaust pipe 31 and the downstream side exhaust pipe 32 can move in the width direction of the outboard motor of the outboard motor 1 with respect to the other. Therefore, if there is a difference between the thermal expansion amount of the guide exhaust 2 and the thermal expansion amounts of the upstream exhaust pipe 31 and the downstream exhaust pipe 32, the upstream exhaust pipe 31 and the downstream exhaust pipe 32 are connected to each other by the guide exhaust. 2 so as to follow the thermal expansion of 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. An exhaust device 7 can be provided.

  The fixing flange 36 of the catalyst 33 according to this embodiment is sandwiched between the upstream exhaust pipe 31 and the downstream exhaust pipe 32 via a metal O-ring 63. Therefore, according to this embodiment, although the upstream side exhaust pipe 31 and the downstream side exhaust pipe 32 are configured to displace following the thermal expansion of the guide exhaust 2, these exhaust pipes 31, The catalyst 33 can be held by 32 connecting portions.

  The metal O-ring 63 according to this embodiment functions as a seal member that prevents leakage of exhaust gas. For this reason, according to this embodiment, it is possible to prevent the exhaust gas from flowing from the upstream side to the downstream side of the catalyst 33 through the connection portion between the upstream side exhaust pipe 31 and the downstream side exhaust pipe 32.

  According to this embodiment, the through-end for inserting the downstream end (upstream catalyst housing half 43) of the upstream exhaust pipe 31 and the upstream end (downstream catalyst housing half 46) of the downstream exhaust pipe is inserted. Cooling water passages 55 and 56 for the exhaust pipes 31 and 32 are formed using the holes 30. For this reason, compared with the case where the cooling water passage surrounding the exhaust passages 47 and 48 is formed in the downstream end portion and the upstream end portion, the exhaust device 7 can be downsized.

In the embodiment shown in FIG. 1 to FIG. 11, an example in which exhaust condensed water and dew condensation water downstream from the catalyst is discharged to the downstream exhaust passage 15 is shown. It can be discharged from the side of the downstream exhaust pipe 32.
FIG. 12 is a diagram showing other examples of drainage passages. In these drawings, the same or equivalent members as those described with reference to FIGS. 1 to 11 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate. To do.

  The downstream drainage passage 72 shown in FIG. 12 is formed so as to guide exhaust condensed water and dew condensation water to a second drainage section 75 located on the rear side of the right side of the outboard motor (left side in FIG. 12). Specifically, the third passage portion 82 of the downstream drainage passage 72 is formed so as to extend from the opening at the lower end of the second passage portion 79 obliquely rearward to the right of the outboard motor. A fourth passage portion 101 extending in the width direction of the outboard motor 1 is connected to the rear end portion of the third passage portion 82.

  The fourth passage portion 101 communicates the third passage portion 82 and the hose joint 102 attached to the downstream side exhaust pipe 32. The hose joint 102 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 72 is configured in this manner, the same effects as those of the embodiment shown in FIGS.

  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 DESCRIPTION OF SYMBOLS ... Oil pan, 30 ... Through-hole, 31 ... Upstream exhaust pipe, 32 ... Downstream exhaust pipe, 33 ... Catalyst, 36 ... Fixing flange, 41, 44 ... Exhaust pipe main body, 43 ... Upstream catalyst housing half, 46: half downstream catalyst housing, 55, 56: cooling water passage, 63: metal O-ring.

Claims (4)

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 through-hole that penetrates the outboard motor body in the width direction of the outboard motor is formed at one end of the outboard motor in the longitudinal direction of the outboard motor body,
The exhaust pipe includes an upstream exhaust pipe extending from the exhaust outlet to the through hole at one side in the width direction of the outboard motor, and the through pipe from the exhaust inlet at the other side in the width direction of the outboard motor. A downstream exhaust pipe extending to the hole,
The downstream end of the upstream exhaust pipe and the upstream end of the downstream exhaust pipe are movably fitted into the through holes in a state where the outflow of exhaust gas is regulated,
An outboard motor exhaust system in which an elastic member is sandwiched between the downstream end and the upstream end. The exhaust system for an outboard motor according to claim 1, wherein the catalyst is housed in a downstream end portion of the upstream exhaust pipe and an upstream end portion of the downstream exhaust pipe; A fixing flange located between the upstream end and the downstream end,
The elastic member is an outboard motor provided between the downstream end of the upstream exhaust pipe and the flange and between the upstream end of the downstream exhaust pipe and the flange. Exhaust system.   3. The exhaust system for an outboard motor according to claim 1, wherein the elastic member includes an annular metal pipe, and a downstream end portion of the upstream exhaust pipe and an upstream end portion of the downstream exhaust pipe. An exhaust device for an outboard motor that functions as a sealing member that prevents leakage of exhaust gas between the two. 4. The outboard motor exhaust device according to claim 1, wherein the upstream side exhaust pipe and the downstream side exhaust pipe are provided with a lid for closing the opening of the through hole. ,
An outboard motor exhaust system in which a cooling water passage is formed between a hole wall surface of the through hole and an upstream exhaust pipe and a downstream exhaust pipe.

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