JP3491775B2 - Outboard expansion chamber mounting structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting an expansion chamber formed in the exhaust passage of an outboard motor mounted on a small boat, and more particularly to a catalyst formed in a bag shape on the lower surface of an exhaust guide. The present invention relates to an expansion chamber mounting structure in an outboard motor having an expansion chamber accommodating therein.

[0002]

2. Description of the Related Art In an outboard motor mounted on a small boat, a housing for the entire outboard motor is usually formed by a top cowl, an upper case and a lower case, and an exhaust guide is arranged between the top cowl and the upper case. The engine, in which the crankshaft is arranged in the vertical direction, is mounted in the top cowl on the upper surface of the exhaust guide, and is rotatably driven by the engine via the drive shaft, the shift conversion gear and the propulsion shaft. Machine (screw)
Is pivotally supported by the lower case.

The exhaust passage from the engine in such an outboard motor extends downward from the engine so that exhaust gas passes through the upper case and is discharged from the lower case below the water surface to the outside of the engine. Is opened in the lower case, but it is necessary to make the exhaust passage as long as possible in order to effectively reduce exhaust noise and secure a space for installing a catalyst that purifies exhaust gas. Come on.

However, in the conventional outboard motor, since the exhaust passage is structured to simply extend in the vertical direction from the engine, there is a limit in extending the exhaust passage as it is without increasing the size of the outboard motor itself. Also, when a catalyst is installed in the exhaust passage, depending on the attitude of the hull, water that has entered from below the exhaust passage may come into contact with the catalyst. The problem of doing.

Therefore, in order to solve the above problems while making the outboard motor compact without increasing the size of the outboard motor, the exhaust passage of the outboard motor is stored in the lower surface of the exhaust guide below the engine. Form a bag-shaped expansion chamber,
The applicant of the present invention has proposed that the folded portion that extends upward from the expansion chamber and then bends downward is formed by a high riser and a return pipe, and that the folded portion is arranged in the width direction of the hull.

[0006]

By the way, in the outboard motor, water (seawater) continuously pumped up by a pump is supplied to the engine as cooling water and then dropped in the upper case before being discharged out of the engine. The engine and the exhaust passage are cooled by, and the periphery of the exhaust passage in the upper case is exposed to the dropped cooling water.

Therefore, in the structure in which the bag-shaped expansion chamber containing the catalyst is attached to the lower surface of the exhaust guide, the cooling water in the upper case leaks from the gap between the lower surface of the exhaust guide and the upper end of the expansion chamber, The invading cooling water (seawater) deteriorates the purification performance of the catalyst contained in the expansion chamber because the expansion chamber is bag-shaped and the invading water does not escape.

An object of the present invention is to eliminate the disadvantages of the expansion chamber mounting structure for an outboard motor as described above.
More specifically, in an outboard motor in which an expansion chamber, which is formed in a bag shape and contains a catalyst, is attached to the lower surface of the exhaust guide, seawater may enter the expansion chamber due to water leakage from the upper case. It is an object of the present invention to provide an expansion chamber mounting structure for an outboard motor that can prevent deterioration of the catalyst purification performance due to contact with seawater.

[0009]

In order to solve the above-mentioned problems and to achieve the object, the present invention is formed in a bag shape on the lower surface of an exhaust guide arranged between a top cowl and an upper case. Attached to the expansion chamber,
In an outboard motor containing a catalyst, a flange extending outward from the upper end of the expansion chamber is integrally formed, and the peripheral edge of the flange is sandwiched between the upper end of the upper case and the lower surface of the exhaust guide. It is characterized by.

In the expansion chamber mounting structure for an outboard motor as described above, the expansion guide is provided on the lower surface of the exhaust guide on the side of the expansion chamber.
When a return pipe that communicates with the expansion chamber via an inverted U-shaped high riser attached to the upper surface of the exhaust guide is arranged, the return pipe may be integrally formed on the lower surface of the flange of the expansion chamber, or the expansion pipe may be expanded. A return pipe may be separately connected to the lower surface of the flange of the chamber.

[0011]

[0012]

[Operation] According to the above configuration, since the flange peripheral portion of the expansion chamber is placed on the upper case so as to cover the upper end of the upper case, water in the upper case leaks from the mounting portion of the expansion chamber. Even so, it will leak to the outside of the outboard motor through the gap between the lower surface of the flange and the upper end of the upper case, and will not enter the expansion chamber.

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an outboard motor expansion chamber mounting structure of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the outboard motor 1 has a swivel arm 4 pivotally attached to a clamp bracket 3 fixed to a rear plate 2 of the hull so as to be vertically swingable,
It is elastically supported through two upper and lower damper members 5a and 5b, and its housing is formed by the top cowl 6, the upper case 7, and the lower case 8, and the engine 9 is housed in the top cowl 6. The lower case 8 is rotatably supported by a propulsion device (screw) 10 which is rotationally driven by an engine 9.

The top cowl 6 for housing the engine 9 is
It consists of an upper cowl 6a and a bottom cowl 6b, and an exhaust guide 11 is arranged between the bottom cowl 6b and the upper case 7 so as to partition the inside of the top cowl 6 and the inside of the upper case 7, and the engine 9 is equipped with an exhaust guide. It is mounted on the upper surface of the exhaust guide 11, and a bottom cowl 6b is fixed to the peripheral edge of the upper surface of the exhaust guide 11 and an upper case 7 is fixed to the peripheral edge of the lower surface by bolting.

The engine 9 mounted in the top cowl 6 has a crankshaft 12 common to each cylinder vertically arranged, and three pairs of cylinders 9a are arranged as shown in FIG.
The respective exhaust ports of the three cylinders, which are arranged so as to form a V bank and are vertically overlapped with each other, merge with each other and then are led out to a pair of exhaust ports 9b formed on the lower surface of the engine.

The output portion 12a at the lower end of the crankshaft 12 placed in the vertical direction is connected with the upper end of a drive shaft 15 which vertically cuts the inside of the upper case 7.
A bevel gear 15a that meshes with a shift conversion gear portion 16a of a propulsion shaft 16 that is pivotally supported by the lower case 8 and that has the propulsion device 10 splined at its rear end is coupled to the lower end of the drive shaft 15 In the middle, as shown in FIG.
A cooling water pump 17 that operates in conjunction with the drive shaft 15 is provided.

The exhaust guide 11 arranged between the bottom cowl 6b of the top cowl 6 and the upper case 7 is manufactured by die casting using an aluminum alloy as a material, and as shown in FIG. A mounting seat 11a for mounting the damper member 5a on the upper side is formed on the upper surface, and a pair of exhaust holes 11b communicating with a pair of exhaust ports 9b of the engine 9 are formed behind the mounting seat 11a, and an exhaust hole 11b. The expansion chamber communication hole 11c is provided on one side of the rear side of the
However, the return pipe communication holes 11d are formed on the other side so as to vertically pass through the exhaust guide 11, respectively.

The exhaust guide 11 has a cooling water jacket 11e surrounding the expansion chamber communication hole 11c and the return pipe communication hole 11d, and the mounting seat 1
A cooling water jacket 11m is provided as a closed space formed in the exhaust guide 11 below the la 1 along one side of the exhaust hole 11b, and the cooling water jacket 11e and the cooling water jacket 11m are separated by a partition wall. ing.

A bag-shaped cover body 18 is disposed on the lower surface of the exhaust guide 11 so as to cover the pair of exhaust holes 11b and the expansion chamber communication hole 11c, and the bag-shaped cover body 18 is provided on the lower surface of the exhaust guide 11. An expansion chamber 20 forming a closed space is formed inside by being attached, and exhaust pipes 21 made of heat-resistant stainless steel that do not melt due to exhaust heat are respectively formed in the pair of exhaust holes 11b of the exhaust guide 11. Connected to each exhaust pipe 21
Both are projectingly opened into the expansion chamber 20.

Inside the expansion chamber 20, further behind the exhaust pipe 21, the cylindrical catalyst 22 approaches the longitudinal centerline of the outboard motor as it goes downward in the front-rear direction and the width direction. The upper part of the exhaust guide 11 is fitted into the expansion chamber communication hole 11c in an inclined state with respect to the exhaust guide 11, and the ring-shaped flange 23 obliquely fixed to the outer periphery of the upper part of the catalyst 22 by welding or the like is used. , Is fixed to the peripheral portion of the expansion chamber communication hole 11c on the lower surface of the exhaust guide 11 by bolting.

Further, the exhaust guide 11 of the catalyst 22
As shown in FIG. 1, a step portion 18b is formed on the rear side wall of the cover body 18 so as to prevent the catalyst 22 from coming into contact with the cover body 18, as shown in FIG. A heat insulating space is formed between the catalyst 22 and the catalyst 22.

A return pipe 19 is arranged outside the expansion chamber 20 so as to extend to the lower end of the upper case 7. The return pipe 19 has a lower end opening 1
9a is opened in the lower case 8 and communicates with the outside from the rear end of the propulsion unit 10 via the lower case 8.
Further, as shown in FIG. 7, the lower end of the return pipe 19 is supported by the lower end of the upper case 7 via a seal member 37, whereby the lower end of the upper case 7 is closed.

As shown in FIG. 9, a front expansion chamber 25 is formed in the upper part of the return pipe 19, and an idle exhaust port 24 is provided so as to connect the front expansion chamber 25 and the inside of the return pipe 19. It ’s open, and in response,
A rear expansion chamber 27 is provided at the rear end of the exhaust guide 11.
And an idle hole 28 communicating with this is formed.

The front expansion chamber 25 above the return pipe 19
The rear expansion chamber 27 of the exhaust guide 11 and the rear end portion of the exhaust guide 11 are communicated with each other by the idle passage 26 formed between the cover body 18 and the return pipe 19 and having the lower surface of the exhaust guide 11 as a ceiling wall. The pipe 19 includes an idle exhaust port 24, a front expansion chamber 25,
The idle passage 26, the rear expansion chamber 27, and the idle hole 28 also communicate with the outside.

On the upper surface of the exhaust guide 11, an upstream opening 30a is formed in order to form a bent portion of the exhaust passage.
And the upper bent portion 30b and the downstream side opening portion 30c substantially reverse U
As shown in FIG. 3, the high riser 30 formed in a character shape is arranged so as to bend in the width direction of the hull, and the bottom face 30d of the upward bend portion 30b of the high riser is the lowermost portion of the engine. Of the expansion chamber 2 is located above the cylinder of the
0, the downstream side opening 30c is the return pipe communicating hole 11
The return pipes 19 communicate with each other via d.

Above the high riser 30, which is located outside the lower rear part of the engine 9 and is located on the upper surface of the exhaust guide 11, a CD is provided above the V bank of the engine 9.
An I unit 41 is provided, and a regulator 42 is provided above the CDI unit 41 and near the air intake 43.

The diameter and the bend R of the high riser 30 are set so that the influence on the engine output is minimized, and the upstream opening 30a and the upward bend 30b are provided.
As shown in FIG. 9, a concave portion 30f is formed on the side opposite to the engine 9 by the portion surrounded by the downstream opening portion 30c and the bottom wall 30g of the concave portion 30f is fixed to the upper surface of the exhaust guide 11. Therefore, the bolt 35 is arranged.

In this way, the concave portion 30f is formed on the side opposite to the engine 9, and the high riser 3 is formed in the concave portion 30f.
Since the bolt 35 for fixing the central portion of 0 is arranged, the bolt 35 can be easily attached and detached without interfering with the engine 9.

The high riser 30 has an exhaust passage 30
a, 30b, 30c so as to enclose the outer surface, that is, the cooling water jacket 30e portion on the inner circumferential side surrounded by the exhaust passages 30a, 30b, 30c and the exhaust passages 30a, 30b, 30c shown in FIG. A bag-shaped cooling water jacket 30e is formed so that all of the cooling water jacket 30e on the outer peripheral side communicate with each other.

High riser cooling water jacket 30e
Is connected to the cooling water jacket 11e of the exhaust guide by an inflow hole 30h opened at the bottom thereof, and is connected to the outflow hole at the top of the supply hose 33.
Communicates with the cooling water jacket 9c formed on the outer cover of the exhaust manifold of the engine 9.

By connecting the expansion chamber 20 and the return pipe 19 with the high riser 30, the engine 9
The exhaust gas discharged from the exhaust port 9b is expanded in the expansion chamber 20 through the exhaust pipe 21, purified by the catalyst 22, and then passed through the high riser 30 and the return pipe 19.
The lower end 19a of the return pipe during normal operation.
Is discharged into the lower case 8 and then into the water through the propulsion unit 10. During idle operation, the idle exhaust port 24 passes through the front expansion chamber 25, the idle passage 26, and the rear expansion chamber 27 to idle holes. 28 will be discharged into the atmosphere.

Further, as a cooling water passage for cooling the engine and the exhaust passage, as shown in FIG. 2, a supply pipe 31 connected to the cooling water pump 17 is provided outside the cover body 18 and the return pipe 19. The cooling water, which extends upward in the upper case 7 and is pumped up by the cooling water pump 17, cools the expansion chamber 20 by the supply pipe 31 passing near the outer surface of the expansion chamber 20 while flowing from the inflow hole 11f. It is fed into the exhaust guide 11.

The inflow hole 11f to which the supply pipe 31 from the cooling water pump 17 is connected is opened at the lower surface of the exhaust guide 11 near the center in the front-rear direction, and is covered by the cover member 18 and the return pipe 19 below the exhaust guide. It is located in a place that is far from the part that is covered.

The cooling water sent to the inflow hole 11f of the exhaust guide 11 has a first passage 11w for directly supplying the cooling water to the engine 9 side in the exhaust guide 11.
The cooling water, which is branched by the second passage 11v that supplies the cooling water to the cooling water jacket 11e of the exhaust guide and flows to the first passage 11w side, passes through the water passage in the exhaust guide 11 directly to the cooling water jacket 9c of the engine 9.
The cooling water supplied to the high passage 30 is supplied to the high riser 30 via the cooling water jacket 11e.

The cooling water jacket 11e formed in the exhaust guide 11 covers the upper side of the expansion chamber 20, and the expansion chamber communication hole 11c and the return pipe communication hole 11d.
It is formed as a single closed hollow space that surrounds the periphery of the exhaust guide 1 and is communicated to the outside only through the inflow hole 11f and the outflow hole 11g.
1 outflow holes 11g opened on the upper surface of the high riser 3
It is arranged so as to be connected to the inflow hole 30h formed facing the 0 side.

From the second passage 11v to the cooling water jacket 11
The cooling water sent to e is exhaust hole 11b, expansion chamber communication hole 11c, return pipe communication hole 11d and expansion chamber 20.
After being cooled above, it is supplied to the high riser 30 through each outflow hole 11g on the upper surface of the exhaust guide 11.

Cooling water jacket 1 for the exhaust guide
The cooling water sent from the 1e to the high riser 30 cools the high riser 30 by the cooling water jacket 30e, and then the supply hose 3 is supplied from the top of the cooling water jacket 30e.
3 is supplied to the cooling water jacket 9c of the engine 9 via the first passage 11w and is directly supplied to the cooling water jacket 9c of the engine 9 via the first passage 11w. Inflow hole 1
Cooling water jacket 11m from 1k to exhaust guide
Run down.

The cooling water jacket 11m formed in the exhaust guide 11 covers the upper part of the expansion chamber 20 and is formed as one hollow closed space below the mounting seat 11a and along one side of the exhaust hole 11b. As shown in FIG. 10, the inflow hole 11k and the outflow hole 11n are
Cooling water jacket 1 that communicates only with the outside
It is separated from 1e by a partition wall.

Cooling water jacket 1 for the exhaust guide
The cooling water flowing into 1 m cools the upper part of the mounting seat 11a, the exhaust hole 11b and the expansion chamber 20 in the cooling water jacket 11m, and then covers from the outflow hole 11n opened laterally on the lower surface of the exhaust guide 11. It passes through a drop hole 18d opened at the periphery of the flange portion 18a of the body 18 and falls into the upper case 7, and accumulates in the upper case 7 to cool the expansion chamber 20 and the return pipe 19 and then pass through the overflow pipe 34. It is discharged from the lower case 8 to the outside.

In the outboard motor as described above, the expansion chamber 20
The bag-shaped cover body 18 for forming the structure and the return pipe 19 arranged outside the cover body 18 are shown in FIG.
As shown in FIG. 5, the side walls are integrally formed by die casting using an aluminum alloy so that the facing portions of the side walls form a common boundary wall.

A flange 18a extending outward is integrally formed from the upper end of the cover body 18, and a return pipe 19 is integrally formed from a part of the lower surface of the flange portion 18a. The upper ends of the return pipe 19 and the return pipe 19 are common to both flanges 18a.
Each has a structure integrally molded continuously.

The cover body 1 integrally formed in this way
8 and the return pipe 19 have a common peripheral edge of the flange 18a and the upper end of the upper case 7 and the exhaust guide 1.
1 is sandwiched between the lower surfaces of the first and second parts, and the bolts 3 are attached to the exhaust guide 11 and the upper case 7 at that portion.
The cover body 18 and the return pipe 19 are fixed to the lower surface of the exhaust guide 11 at the same time by being tightened by 8, 39.

At the mating surface of the upper surface of the flange 18a and the lower surface of the exhaust guide 11, the upper end of the cooling water supply pipe 31 is separated from the portion surrounded by the cover body 18 and the return pipe 19, as shown in FIG. Where
Front expansion chamber 25 provided above return pipe 19
Is located adjacent to, and penetrates the flange 18a at this position to be connected to the lower surface of the exhaust guide 11.

In the present embodiment of the outboard motor as described above, when the propulsion device 10 is rotationally driven by the operation of the engine 9 via the drive shaft 15 and the propulsion shaft 16, the boat is traveling, Exhaust gas from the engine is introduced from the exhaust pipe 21 into the expansion chamber 20, where it is expanded and then the catalyst 2
Purified in 2, high riser 30, return pipe 19
Through the lower case 8 and discharged into the water from the rear end of the propulsion unit 10.

At this time, since the high riser 30 bent in the width direction of the hull is provided above the exhaust guide 11, the entire exhaust passage is formed long without changing the vertical dimension of the exhaust passage. As a result, the exhaust noise is effectively reduced.

Even if the water level with respect to the outboard motor changes depending on the running posture of the hull, the high riser 30 above the exhaust guide 11 causes the return pipe 19 and the expansion chamber 18 to move.
Since it exists so as to project largely upward between the two, the water that has entered the return pipe 19 as a barrier does not enter the expansion chamber 20 of the cover body 18, and therefore the expansion chamber It is surely prevented that the water that has entered the catalyst 22 in 20 comes into contact with the catalyst 22 to deteriorate its performance.

The flange 18a at the upper end of the expansion chamber 20
Since the peripheral edge of the flange is sandwiched between the upper end of the upper case 7 and the lower surface of the exhaust guide 11, the flange 1
Even if the water in the upper case 7 leaks from the mounting portion of the expansion chamber 20 such that the peripheral edge of the 8a covers the upper end of the upper case 7, the space between the lower surface of the flange 18a and the upper end of the upper case 7 may be removed. The cooling water will not leak into the expansion chamber 20 as it leaks to the outside of the external unit.

Further, since the cooling water passage for supplying the cooling water to the engine 9 has a higher water pressure than the cooling water passage for discharging the cooling water from the engine, the supply pipe 31 and the lower surface of the exhaust guide 11 are connected. Although there is a risk of water leakage at the part, even if water leaks at the location and water enters the mating surface of the flange 18a and the exhaust guide 11,
The supply pipe 31 is provided on the return pipe 19 side (the front expansion chamber 2
5 (adjacent to No. 5) and there is a pressure difference between the expansion chamber 20 and the return pipe 19 (exhaust pressure in the expansion chamber 20 is higher than that in the return pipe 19), so it enters the mating surface. Returned water 1 (from front expansion chamber 25)
9 is prevented from being sucked into the expansion chamber 20 and entering the expansion chamber 20.

As described above, the expansion chamber mounting structure of the outboard motor of the present invention has the cover body 18 and the return pipe 1 as shown in FIG.
However, the present invention is not limited to such a configuration. For example, the cover body 18 and the return pipe 19 may be formed separately. It is possible.

For example, in another embodiment as shown in FIG. 8, a flange 18a integrally extending outward from the upper end of the cover body 18 is formed and the flange 18a is formed.
Exhaust guide 11 return pipe communication hole 11
A through hole 18b is formed in the flange 18a below d.

A separate return pipe 19 is arranged below the through hole 18b of the flange 18a, and the return pipe 19 sandwiches the flange 18a between the bolts 4a.
It is fastened together with the lower surface of the exhaust guide 11 by 0, and the peripheral edge of the flange 18a is sandwiched between the lower surface of the exhaust guide 11 and the upper end of the upper case 7.

By forming the cover body 18 and the return pipe 19 as separate bodies as in this embodiment, it becomes easy to perform casting and molding of the portion with a die.

[0055]

According to the expansion chamber mounting structure for an outboard motor of the present invention as described above, the outboard chamber having the expansion chamber formed in the shape of a bag and containing the catalyst is mounted on the lower surface of the exhaust guide. In the machine, seawater does not enter the expansion chamber from the mounting portion of the expansion chamber due to water leakage from the inside of the upper case, and deterioration of the purification performance of the catalyst due to contact with seawater can be prevented.

[0056]

[Brief description of drawings]

FIG. 1 is a partial cross-sectional left side view schematically showing an outboard motor to which an embodiment of an expansion chamber mounting structure of the present invention is applied.

2 is a partial cross-sectional right side view of an outboard motor main part of the embodiment shown in FIG.

FIG. 3 is a partial cross-sectional rear view of the main part of the outboard motor of the embodiment shown in FIG.

4 is a top view of the engine portion of the embodiment shown in FIG.

5 is a top view of the exhaust guide portion of the embodiment shown in FIG.

FIG. 6 is a top view of a portion lower than the exhaust guide of the embodiment shown in FIG.

7 is a cross-sectional rear view of the main part of the embodiment shown in FIG.

FIG. 8 is a cross-sectional rear view of the main part corresponding to FIG. 7 in another embodiment.

FIG. 9 is a partial cross-sectional side view of the embodiment shown in FIG.

10 is a sectional view of the exhaust guide and the upper case taken along the line AA in FIG.

[Explanation of symbols]

1 Outboard Motor 6 Top Cowl 7 Upper Case 11 Exhaust Guide 18a Flange (of Expansion Chamber) 19 Return Pipe 20 Expansion Chamber 22 Catalyst 30 High Riser 31 Supply Pipe (Cooling Water Passage for Supplying Cooling Water to Engine)

Continuation of the front page (56) Reference JP-A-6-146876 (JP, A) JP-A-5-246389 (JP, A) JP-A-5-229488 (JP, A) JP-A-4-39195 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B63H 20/24

Claims (3)

(57) [Claims] 1. A bag-shaped member is formed on the lower surface of an exhaust guide disposed between the top cowl and the upper case.
In an outboard motor in which the expansion chamber is attached and the catalyst is housed in the expansion chamber, a flange extending outward from the upper end of the expansion chamber is integrally formed, and the peripheral portion of the flange is the upper case. An expansion chamber mounting structure for an outboard motor, which is sandwiched between an upper end and a lower surface of an exhaust guide. 2. A return pipe, which is communicated with the expansion chamber via an inverted U-shaped high riser attached to the upper surface of the exhaust guide, is provided on the side of the expansion chamber on the lower surface of the exhaust guide. The expansion chamber mounting structure for an outboard motor according to claim 1, wherein the flange is integrally formed on a lower surface of a flange extending from an upper end of the outboard motor. 3. A return pipe, which is communicated with the expansion chamber via an inverted U-shaped high riser attached to the upper surface of the exhaust guide, is disposed on the side of the expansion chamber on the lower surface of the exhaust guide. The expansion chamber mounting structure for an outboard motor according to claim 1, wherein the flange is extended from the upper end of the shaft and is separately connected to the lower surface of the flange.