JP4819115B2 - Outboard motor - Google Patents

Description

  The present invention relates to an outboard motor including an internal combustion engine in which a combustion chamber is formed and an intake silencer that reduces intake noise.

In an outboard motor, in order to reduce intake noise, there is known an intake silencer disposed in an engine room formed by an engine cover (see, for example, Patent Documents 1 and 2).
JP 2002-235621 A JP-A-5-286490

  In an outboard motor equipped with an internal combustion engine, in order to reduce intake noise caused by intake air pulsation of the internal combustion engine, there is a limit to the effect of reducing the intake noise only by providing one intake silencer. Therefore, in order to increase the intake noise reduction effect, it is conceivable to provide a plurality of intake silencers. However, the provision of a plurality of intake silencers simply increases the size of the outboard motor.

The present invention has been made in view of such circumstances, and utilizes the fact that the bottom wall of the upstream side intake silencer and the top wall of the downstream side intake silencer are formed in complementary stepped shapes. An object of the present invention is to reduce the size of the outboard motor in the vertical direction by arranging both the intake silencers compactly in the vertical direction while enhancing the effect of reducing the intake noise by the dual intake silencers.

The invention according to claim 1 is an outboard motor comprising an internal combustion engine (E) in which a combustion chamber (22) is formed, and an upper intake silencer (50) into which combustion air flows and an upper intake silencer ( 50) and a lower intake silencer (60) for directing combustion air from the combustion chamber (22) to be stacked one above the other and disposed above the lower intake silencer (60) The upper intake silencer (50) is provided with an air inlet (51i), an upper expansion chamber (51a), and an air outlet (51o), and the lower intake silencer (60) An intake inlet (61i) connected to the air outlet (51o), a lower expansion chamber (61a), and an intake outlet (61o) are provided, and the top wall (67 of the lower expansion chamber (61a) is provided. ) Overlaps with the lower high wall portion (67a) and the bottom wall (53) of the upper expansion chamber (51a) in plan view, and is positioned below the lower high wall portion (67a). A wall having a wall portion (67b), and the intake inlet (61i) The outboard motor is arranged on the wall (67b).
According to a second aspect of the present invention, in the outboard motor according to the first aspect, the bottom wall (53) of the upper expansion chamber (51a) has an upper high wall that overlaps the lower intake silencer (60) in plan view. A step-shaped wall having a portion (53a) and an upper low wall portion (53b) positioned below the upper high wall portion (53a) without overlapping the lower intake silencer (60) in plan view The air outlet (51o) is arranged in the upper high wall (53a).
The invention according to claim 3 is the outboard motor according to any one of claims 1 to 2 , wherein the upper intake silencer (50) and the lower intake silencer (60) are the internal combustion engine (E ) Is disposed across an engine cover (15) that forms an engine room (R) in which the upper intake silencer (50) is disposed outside the engine room (R) and the engine cover (15). ) And an exterior cover (27, 28) covering the engine cover from above, the lower intake silencer (60) is disposed in the engine room (R). It is characterized by being arranged in.

According to the first aspect of the present invention, since the lower high wall portion of the top wall formed in a step shape in the lower intake silencer is disposed above the lower lower wall portion, the lower expansion chamber The volume of the intake air can be increased, and the effect of reducing the intake noise by the lower intake silencer can be enhanced.
Further, the lower low wall portion provided with the intake inlet connected to the air outlet port of the upper intake silencer is formed directly above the upper intake silencer so as to be formed above the lower low wall portion. The upper intake silencer is placed in the space where As a result, by using the low wall portion that overlaps the upper intake silencer in plan view on the top wall having the high wall portion and the low wall portion, both the intake silencers are connected while the air outlet and the intake inlet are connected. Since the air conditioners can be arranged close to each other in the vertical direction, both intake silencers can be compactly arranged in the vertical direction, and the outboard motor can be downsized in the vertical direction.
According to the second aspect of the present invention , since the bottom wall of the upper intake silencer and the top wall of the lower intake silencer are formed in complementary shapes, the upper side of the bottom wall of the upper intake silencer The low wall portion does not overlap with the lower intake silencer in plan view, and the lower high wall portion of the top wall of the lower intake silencer is arranged above the lower low wall portion. The volume of both expansion chambers can be increased, and the intake noise reduction effect of both intake silencers can be enhanced.
Further, the lower low wall portion where the intake inlet is provided is arranged directly below the upper high wall portion where the air outlet is provided, so that the lower high wall is formed in a space formed below the upper high wall portion. A lower low wall portion located below the portion is disposed. As a result, by using the high wall portion and the low wall portion that overlap each other in plan view in both intake silencers, both intake silencers can be arranged close to each other in the vertical direction while connecting the air outlet and the intake inlet. As a result, both intake silencers can be arranged compactly in the vertical direction, and the outboard motor can be miniaturized in the vertical direction.
According to the third aspect of the present invention , the upper intake silencer and the lower intake silencer are separately arranged outside the engine room and inside the engine room, and the upper intake silencer is formed by the engine cover and the exterior cover. Therefore, the engine cover and the outboard motor can be downsized. In addition, since the engine cover is downsized, the vibration of the engine cover due to the intake pulsation attenuated by the both intake silencers is further suppressed, so that the noise caused by the vibration of the engine cover due to the intake pulsation is reduced.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
1 to 3, an outboard motor S as a marine vessel propulsion device to which the present invention is applied includes a power unit P, a propeller 20 as a thrust generating member driven by the power unit P, and a power unit. And an attachment device 21 for attaching P to the hull T. The power unit P includes an internal combustion engine E as an engine, a power transmission device that transmits power generated by the internal combustion engine E to the propeller 20, an engine cover 15 that forms an engine room R in which the internal combustion engine E is accommodated, and the like. Covers, an intake silencer 50 as an air intake part that takes in combustion air of the internal combustion engine E, and a ventilation device that ventilates the engine room R in which the internal combustion engine E is housed.

The internal combustion engine E is a water-cooled multi-cylinder four-stroke internal combustion engine including a plurality of cylinders 1a, and in this embodiment is a V-type six-cylinder internal combustion engine, and further includes a crankshaft 8 having a rotation center line Le directed vertically. Is an institution. The internal combustion engine E includes a cylinder block 1 in which six cylinders 1a into which pistons 6 are reciprocally fitted are formed so as to form a pair of V-shaped banks opened rearward in a plan view. , A pair of cylinder heads 2 coupled to the rear end of each bank of the cylinder block 1, a pair of head covers 3 coupled to the rear end of each cylinder head 2, and a front end of the cylinder block 1 And an engine main body (hereinafter referred to as “engine main body”).
The cylinder head 2 and the head cover 3 are rear end members of the engine main body, and the crankcase portion 4 is a front end member that is a portion of the engine main body positioned in front of the rotation center line Le.
The piston 6 that fits into the cylinder hole 1 b of each cylinder 1 a is connected to the crankshaft 8 via a connecting rod 7. The crankshaft 8 is disposed in a crank chamber 5 formed by a crankcase composed of a front portion 1c and a crankcase portion 4 which are portions near the crankshaft 8 in the cylinder block 1, and the crankcase 8 is mainly disposed in the crankcase. The bearing 9 is rotatably supported.

  In the specification and claims, the up-down direction, the front-rear direction, and the left-right direction are the up-down direction, the front-rear direction, and the left-right direction in the hull T, respectively, and as shown in FIG. It is assumed that the direction of the line Le (hereinafter referred to as “rotation center line direction”) coincides with the up-down direction, and the horizontal direction orthogonal to the up-down direction includes the front-rear direction and the left-right direction. . When one of the upper and lower sides is one direction in the rotation center line direction, the other of the upper and lower sides is the other direction in the rotation center line direction, and one of the front and rear is one direction in the front-rear direction. The other of the front and rear is the other direction in the front-rear direction. Further, the plan view means viewing from the vertical direction or the rotation center line direction, and the circumferential direction is a circumferential direction centering on the rotation center line Le unless otherwise specified.

  The engine body is coupled to the upper end of the mount case 10, the oil pan 11 and the extension case 12 surrounding the oil pan 11 are coupled to the lower end of the mount case 10, and the gear case 13 is coupled to the lower end of the extension case 12. . The lower part of the internal combustion engine E, the upper part of the mount case 10 and the extension case 12 are covered by a lower cover 14 coupled to the extension case 12, and the engine that covers most of the upper cover including the upper part of the internal combustion engine E at the upper end of the lower cover 14 Cover 15 is joined. The engine cover 15 and the lower cover 14, which is a separate member from the engine cover 15, form an engine room R in which the internal combustion engine E is disposed. The engine cover 15 includes a peripheral wall 15a that extends in the circumferential direction around the rotation center line Le and surrounds the internal combustion engine E in the horizontal direction, and a ceiling wall 15b that covers the internal combustion engine E from above. In the engine room R, a generator G that is an AC generator as an auxiliary machine provided in the internal combustion engine E is disposed.

A flywheel 16 and a drive shaft 17 are coupled to the lower end portion of the crankshaft 8 as an output shaft of the internal combustion engine E. The drive shaft 17 that is rotationally driven by the crankshaft 8 is disposed so as to extend downward in the mount case 10 and the extension case 12 and reach the gear case 13, and the rotation transmitted from the drive shaft 17 in the gear case 13. Is coupled to the propulsion shaft 19 via a forward / reverse switching device 18 for controlling Therefore, the power of the internal combustion engine E is transmitted from the crankshaft 8 through the drive shaft 17, the forward / reverse switching device 18 and the propulsion shaft 19 to the propeller 20 coupled to the propulsion shaft 19, and the propeller 20 is rotationally driven. . The rotation center line of the drive shaft 17 coincides with the rotation center line Le in this embodiment, but may be parallel to the rotation center line Le.
Here, the engine cover 15, the lower cover 14, the mount case 10, the extension case 12 and the gear case 13 constitute the above-mentioned covers, and the drive shaft 17, the forward / reverse switching device 18 and the propulsion shaft 19 are generated by the internal combustion engine E. The power transmission device that transmits the power to be transmitted to the propeller 20 is configured.

  The mounting device 21 (see FIG. 1) includes a swivel case 21c that rotatably supports a swivel shaft 21b that is fixed to the mount case 10 and the extension case 12 via a mount rubber 21a, and a swivel case 21c that can rotate. And a bracket 21e fixed to the stern of the hull T. The power device P to which the propeller 20 is attached by the attachment device 21 can swing with respect to the hull T in the vertical direction about the tilt shaft 21d, and can swing in the left-right direction about the swivel shaft 21b. .

Referring to FIG. 2, the cylinder head 2 includes a combustion chamber 22 that faces the piston 6 in the cylinder axial direction, an intake port and an exhaust port that open to the combustion chamber 22, and an ignition that faces the combustion chamber 22. And a stopper. The cylinder hole 1b between the piston 6 and the combustion chamber 22 in the cylinder axial direction constitutes a combustion space in which the air-fuel mixture burns together with the combustion chamber 22 formed by the cylinder head 2. The intake valve and the exhaust valve provided in the cylinder head 2 are driven by an overhead camshaft type valve operating device 23 housed in a valve operating chamber formed by the cylinder head 2 and the head cover 3 to rotate the crankshaft 8. The intake port and the exhaust port are opened and closed in synchronization.
The valve gear 23 includes a camshaft 23a that is rotationally driven by the power of the crankshaft 8 transmitted through the valve gear transmission mechanism 24, an intake cam 23b and an exhaust cam 23c provided on the camshaft 23a. The rocker arm shaft 23d includes an intake rocker arm 23e and an exhaust rocker arm (not shown) that are swingably supported. Then, the intake cam 23b and the exhaust cam 23c open and close the intake valve and the exhaust valve via the intake rocker arm 23e and the exhaust rocker arm.

Referring also to FIG. 3, at the upper end of the crankshaft 8, a valve drive pulley 24a and an accessory drive pulley 25a are sequentially provided upward. Provided on the drive pulley 24a, the cam pulley 24b provided on the cam shaft 23a, and the valve transmission mechanism 24 having the belt 24c spanned between the pulleys 24a, 24b, the drive pulley 25a and the rotating shaft 101 of the generator G. The auxiliary transmission mechanism 25 having the driven pulley 25b and the belt 25c spanned between both pulleys 25a and 25b is covered from above by a belt cover serving as a transmission cover coupled to the upper end of the engine body. Both are disposed in the engine room R. The belt cover is disposed directly above each cylinder head 2 and the uppermost cylinder 1a, and an intake silencer 60 serving as an intake passage part that covers most of the cam pulley 24b and the belt 24c, and the crankcase or the crank chamber 5 And a drive passage 24a, 25a, a driven pulley 25b, a part of the belt 24c, and a discharge passage part 90 that covers the entire belt 25c. The belt 24c is also stretched over a tensioner 24d and two idle pulleys 24e and 24f.
In addition, the intake silencer 60 and the exhaust passage component 90, both of which are disposed in the engine room R, are separate components and a separate component from the engine cover 15, and are arranged side by side in the front-rear direction. The belt cover is divided into two in the front-rear direction covering the transmission mechanisms 24, 25 from above.

  The internal combustion engine E includes an intake device 30 disposed in the engine room R. Combustion air flowing in the intake passage formed by the intake device 30 is mixed with fuel supplied from a fuel injection valve to form an air-fuel mixture, and the air-fuel mixture is ignited in the combustion chamber 22 by the spark plug. Burn. The piston 6 that is driven by the pressure of the generated combustion gas and reciprocates drives the crankshaft 8 through the connecting rod 7. Referring also to FIG. 1, the combustion gas flows as exhaust gas from the combustion chamber 22 through the exhaust port and the exhaust manifold provided in the cylinder head 2 sequentially into the exhaust pipe 26 (see FIG. 1). The exhaust pipe 26 is discharged to the outside of the outboard motor S through an exhaust passage (not shown) provided in the extension case 12, the gear case 13, and the boss of the propeller 20.

  1-3, power unit P is disposed outside engine room R (that is, outside engine room R) and directly above engine room R (or ceiling wall 15b of engine cover 15). An air passage device is provided. The air passage device introduces outside air, which is air outside the outboard motor S, into the intake device 30 as combustion air to the intake device 30, and introduces outside air into the engine room R as ventilation air while the engine room. Ventilation passage parts for discharging the ventilation air in R to the outside of engine room R (or outside of outboard motor S).

4 to 6 together, the air passage device includes an exterior cover that is detachably attached to the ceiling wall 15b. The exterior cover that forms the exterior of the outboard motor S together with the engine cover 15 is disposed between the top cover 27 that constitutes the uppermost portion of the outboard motor S, and the top cover 27 and the ceiling wall 15b or the engine room R. And an intermediate cover 28 covered with a top cover 27 from above.
The engine cover 15, the top cover 27, and the intermediate cover 28 are all a single member molded by a molding die using a synthetic resin as a forming material.
The intermediate cover 28, which is an intermediate member, is disposed with a space in the vertical direction between the top cover 27 and the ceiling wall 15b of the engine cover 15, and the top cover 27 is attached to the ceiling wall 15b via the intermediate cover 28. It is done. Therefore, the engine cover 15 and the top cover 27 are coupled via the intermediate cover 28. The ceiling wall 15b is covered from the upper part by the intermediate cover 28 in almost the whole or a majority thereof, and the intermediate cover 28 is covered from the upper part by the top cover 27 in the majority. In the front-rear direction, almost the whole or majority of the intermediate cover 28 is covered with the top cover 27.

  Each of the intake silencer 50 and the ventilation passage part constituted by the introduction part 70 and the lead-out part 80 is constituted by the top cover 27 and the intermediate cover 28. The two covers 27 and 28 allow the combustion air to be introduced into the intake passage of the intake device 30, the air intake passage 51 to introduce the outside air into the engine room R as ventilation air, and the engine room R. An exhaust passage 81 is formed for guiding the air discharged from the engine room R to the outside of the engine room R and further to the outside of the covers 27 and 28, that is, the outside of the outboard motor S.

On the other hand, the gap in the vertical direction formed between the ceiling wall 15b and the intermediate cover 28 constitutes an air intake space 40 that guides outside air to the air intake passage 51 as combustion air.
Thus, a lower space constituted by the air intake space 40 is formed below the intermediate cover 28 with the intermediate cover 28 as a boundary, and the air intake passage 51, the introduction passage 71, and the outlet passage 81 are formed above the intermediate cover 28. The upper space comprised by these is formed. Then, between the air intake space 40 and the outlet passage 81, the ceiling wall 15b and the intermediate cover 28 come into contact with each other, thereby preventing or suppressing air leakage.

Referring to FIGS. 2 to 5, 7, and 9, the ceiling wall 15 b and the intermediate cover 28 are provided in both or one of them, and are columnar or trapezoidal in which a screw N <b> 1 as a coupling means is inserted or screwed. Coupled at the coupling portions 15e and 28e. The distance between the ceiling wall 15b and the intermediate cover 28 is defined by the joint portions 15e and 28e contacting each other in the vertical direction.
The air intake space 40 has an opening 41 that extends in the circumferential direction along the entire circumference of the engine cover 15 and the intermediate cover 28. The opening width W (see FIGS. 2 and 12) of the opening 41 is defined by the boundary between the peripheral wall 15a and the ceiling wall 15b and the lower end of the intermediate cover 28. A front end portion 41a (also see FIG. 1) that is a part of the opening 41 is covered and closed by a shielding portion 27a that includes a front end portion that is a part of the top cover 27. A portion of the open port 41 other than the front end portion 41a constitutes an outside air inlet 42 that takes outside air into the air intake space 40 as combustion air. When the main chamber 81a of the lead-out space 81 is substantially divided into a front space and a rear space in the front-rear direction, the shielding portion 27a disposed in front of the intake silencer 50 is separated from the front space in the front-rear direction. It is in almost the same position. The shielding part 27a prevents water from the front from entering the outside air inlet 42.

Further, the top cover 27 and the intermediate cover 28 are coupled to each other at either or both of column-shaped or table-shaped coupling portions 27f and 28f into which screws N2 as coupling means are inserted or screwed. The vertical distance between the top cover 27 and the intermediate cover 28 is defined by the connecting portions 27f and 28f contacting each other in the vertical direction.
The engine cover 15 is coupled to the lower cover 14 after the covers 27 and 28 that are coupled and integrated with each other are coupled to the engine cover 15. Therefore, the engine cover 15 and the top cover 27 are coupled via the intermediate cover 28.
One or more, in this embodiment, the plurality of first coupling portions are all arranged in the up and down direction and distributed in the air intake space 40 between the engine cover 15 and the intermediate cover 28. Each of the first coupling parts includes a coupling part 15e through which the screw N1 is inserted and a coupling part 28e into which the screw N1 is screwed. The coupling portion 15e is formed of a boss that is integrally formed with the ceiling wall 15b at a position facing the coupling portion 28e in the vertical direction and projects upward toward the intermediate cover 28. The coupling portion 28e is formed by being integrally formed with the intermediate cover 28, and includes a boss that projects downward toward the ceiling wall 15b.
The intake silencer 50 and the introduction component 70 are between the engine cover 15 and the first coupling portion as a support portion that is a local portion for supporting the intake silencer 50 on the ceiling wall 15b. Thus, the air intake space 40 is separated from the ceiling wall 15b.

  One or more, in this embodiment, the plurality of second coupling portions are arranged in a vertically distributed manner between the top cover 27 and the intermediate cover 28 in an introduction passage 71 and an expansion chamber 51a described later. Each of the second coupling parts includes a coupling part 28f through which the screw N2 is inserted and a coupling part 27f into which the screw N2 is screwed. The coupling portion 28f is formed of a boss that is integrally formed with the intermediate cover 28 at a position facing the coupling portion 27f in the vertical direction and projects upward toward the top cover 27. The coupling portion 27f is formed by being integrally formed with the top cover 27, and includes a boss that projects downward toward the intermediate cover 28.

  The joint portion 28e is integrally formed at intervals in the circumferential direction of the joint portion 28e, and the rigidity is enhanced by a plurality of ribs 28e1 projecting outward in the radial direction. Further, as shown in FIGS. 4 and 5, the coupling portion 28f that is higher than the other coupling portions 15e, 28e, and 27f (that is, the projection amount is large) is integrally formed with a side wall 54 described later. Reinforced by the side wall 54, its rigidity is enhanced.

With reference to FIGS. 1 to 4, 7, and 8, an upstream side silencer 50 that is disposed outside the engine room R and forms an air suction passage 51 is formed by a part of the top cover 27. A wall 52, a bottom wall 53 formed by the intermediate cover 28, a peripheral wall 54 formed by the intermediate cover 28 and projecting upward between the top wall 52 and the bottom wall 53, and an intermediate cover 28. An introduction duct 55 and a lead-out duct 56. The bottom wall 53 faces the ceiling wall 15b across the air intake space 40 in the vertical direction. The peripheral wall 54 includes a front wall 54a, a rear wall 54b, a left wall 54c, and a right wall 54d. The introduction duct 55 is spaced upward from the ceiling wall 15b.
As shown in FIG. 7, when the engine cover 15 is moved together with the top cover 27 and the intermediate cover 28, the engine cover 15 is connected to the top wall 52, for example, in an integrally coupled state with the top cover 27 and the intermediate cover 28. A grip portion 130 for gripping the top cover 27 when the 15 is attached to and detached from the lower cover 14 is provided. The grip portion 130, which is a member separate from the top cover 27, is a pair of mounting portions formed of bosses that are integrally formed with the intermediate cover 28 while being accommodated in a recess 131 formed in the top wall 52. A bolt 134 inserted into an insertion hole 133 provided in the bottom wall 131a of the recess 131 and a nut 135 that is screwed to the bolt 134 are coupled to 132. The protrusion 136 provided on the bottom wall 131a extends through the expansion chamber 51a in the vertical direction so as to reach the air intake space 40. The protrusion 136 is provided with a water drain hole 137 that opens into the air intake space 40 in order to discharge water that has entered the recess 131.

  Referring to FIGS. 7 and 8, the bottom wall 53 is located below the upper high wall portion 53a that overlaps the intake silencer 60 in plan view and below the high wall portion 53a without overlapping the intake silencer 60 in plan view. A step-shaped wall having an upper lower wall portion 53b. The high wall portion 53a located behind the low wall portion 53b includes a first high wall portion 53a1 in which the outlet duct 56 and the air outlet port 51o are disposed, and above and behind the first high wall portion 53a1. It has the 2nd high wall part 53a2 located.

  Referring to FIGS. 2, 7, and 8, an air intake passage 51 through which air sucked into the internal combustion engine E flows is formed by a chamber wall 57 including a top wall 52, a bottom wall 53, and a side wall 54. An expansion chamber 51a serving as an intake silencer chamber, which is an expansion chamber, and an introduction duct 55, and an air introduction port 51i through which air in the air intake space 40 flows into the expansion chamber 51a, and a discharge duct 56. There is an air outlet 51o through which the air in the expansion chamber 51a flows out to the intake inlet 61i. The passage area of the expansion chamber 51a into which combustion air from the outside air inlet 42 flows is larger than the respective passage areas of the air introduction port 51i and the air outlet port 51o.

  The air introduction port 51i has an upstream end port 51i1 that opens downward into the air intake space 40 and a downstream end port 51i2 that opens into the expansion chamber 51a. The air outlet port 51o has an upstream end port 51o1 that opens to the expansion chamber 51a and a downstream end port 51o2 that opens toward the intake port 61i. The air outlet 51o opens to the intake port 61i through the circulation port 15c and the annular seal member 140 by opening to the circulation port 15c provided in the ceiling wall 15b.

The air outlet 51o and the intake inlet 61i are straight passages parallel to the vertical direction, and the air outlet 51o and the intake inlet 61i are arranged facing each other in the vertical direction.
The upstream end 51i1 of the air introduction port 51i opens into the air intake space 40. In addition, the entire air inlet 51i and the entire air outlet 51o are spaced apart from each other in the front-rear direction and are arranged in the front-rear direction with respect to the rotation center line Le. The downstream end port 51o2 of the air outlet 51o is disposed behind the upstream end port 51i1 of the air introduction port 51i.

Referring to FIGS. 2, 7 and 10, a seal member 140 is integrally formed on the ceiling wall 15b as a part of the engine cover 15, and is provided with a passage forming portion 15m forming a flow port 15c, and an intake silencer. It is disposed between an inlet duct 62 provided integrally with the upper case 60b as a part of 60. The seal member 140 forms a communication port 141 that allows the flow port 15c immediately downstream of the outlet 51o to communicate with the intake port 61i. Therefore, the passage forming portion 15m and the inlet duct 62 are covered with the engine cover 15 integrally coupled to the top cover 27 and the intermediate cover 28 from above the internal combustion engine E attached to the mount case 10 (see FIG. 1). By being coupled to the lower cover 14 (see FIG. 1), they are abutted and connected via the seal member 140.
The passage forming portion 15m and the inlet duct 62 have butt faces J1 and J2 as seal faces facing each other in the butt direction K1, and the seal member 140 is in close contact with both the butt faces J1 and J2, respectively. The space between the forming portion 15m and the inlet duct 62 is sealed. Each abutting surface J1, J2 is a plane substantially perpendicular to the abutting direction K1, or the main flow of air flowing from the intake port 51o to the intake port 61i via the flow port 15c and the communication port 141.

The seal member 140 made of rubber as an elastic material having rubber-like elasticity (that is, elastomer) includes a passage forming portion 15m as a first passage component and a passage forming portion as one passage component of the inlet duct 62 as a second passage component. A lip 142 as a seal portion closely contacting the 15 m butting surface J1, and a seal portion fixed to the butting surface J2 of the inlet duct 62 which is the other passage component of the passage forming portion 15m and the inlet duct 62 by fixing means such as baking. The adhering portion 143, the passage forming portion 15m and the inlet duct 62 are connected to each other at a set interval via the seal member 140 (the state shown in FIG. 10B). In other words, when the lip 142 is pressed by the abutting surface J1 in a state where the engine cover 15 and the intermediate cover 28 are coupled, It includes a flexible portion 144 is elastically deformed to tune the shape is also included.), And a working surface 145 that the pressure of the combustion air as the gas flows through the communication port 141 is exposed to the communication port 141 acts.
The sealing member 140 is provided with a hollow portion 146 filled with air as a filling gas having a predetermined pressure that allows the flexible portion 144 to be bent.

The flexible lip 142 that can be brought into contact with and separated from the butting surface J1 is in a state before the lip 142 is brought into contact with the butting surface J1 (see FIG. 10A). It inclines toward the space 40 and protrudes in a bowl shape. After the flexible portion 144 is bent, it bends to the air intake space 40 side opposite to the communication port 141 with the seal member 140 interposed therebetween.
The flexible portion 144 has a thin portion 144a formed by providing the hollow portion 146 in the seal member 140, and the thin portion 144a is bent.
The working surface 145 is in a state before the pressure is applied to the working surface 145 while the sealing member 140 is pressed by the passage forming portion 15m and the inlet duct 62 in the connected state so that the lip 142 is in close contact with the abutting surface J1 ( 8 (b)), there is a facing surface 145a that faces the butting surface J1 in the direction of the action of the intake negative pressure, which is the pressure of the combustion air in the communication port 141 that allows the flow port 15c and the intake port 61i to communicate with each other. . At this time, a space 141a, which is a part of the communication port 141, is formed between the abutting surface J1 and the facing surface 145a in the direction of the action of the intake negative pressure on the facing surface 145a.
Here, the seal member 140 that seals the space between the air intake space 40 and the circulation port 15c, the intake port 61i, and the communication port 141 includes an action surface 145 that is an inner surface facing the communication port 141, and a communication port. 141 has an outer surface facing the air intake space 40 which is the outer space. A part of the facing surface 145a is also a surface of the flexible portion 144.
Then, when the intake negative pressure acts in a direction perpendicular to the facing surface 145a, an urging force that presses the lip 142 against the abutting surface J1 is generated. For this reason, in addition to the seal pressure at the lip 142 based on the elastic force of the seal member 140 itself, the seal pressure at the lip 142 increases by the amount of the biasing force.

2 to 4, 8, and 9, the introduction duct 55 and the lead-out duct 56 provided integrally with the bottom wall 53 that is a part of the intermediate cover 28 are directed downward from the bottom wall 53. The air duct projects upward from the bottom wall 53 in the expansion chamber 51a without projecting, and the introduction duct 55 suppresses the intrusion of water into the expansion chamber 51a. Intrusion of water into the intake passage is suppressed. The introduction duct 55 is formed of a duct that curves backward toward the air outlet 51o, and deflects the air that flows into the air inlet 51i from below and flows upward toward the air outlet 51o. Thereby, the smoothness of the flow of air flowing in from the air introduction port 51i is enhanced, and the ventilation resistance in the air intake passage 51 is reduced. The air outlet 51o protruding upward from the bottom wall 53 in the expansion chamber 51a is the front in the expansion chamber 51a in the direction in which the air inlet 51i is disposed with respect to the air outlet 51o. It opens to the rear which is the opposite direction. This suppresses the expansion chamber 51a water from entering the air outlet 51o from the air inlet 51i.
The ceiling wall 15b is provided with a raised portion 15p projecting upward in the air intake space 40 between the outside air inlet 42 and the upstream end 51i1 in the front-rear direction and at the same position as the upstream end 51i1 in the left-right direction. It is done.

Referring also to FIG. 11, the outside air intake 42 is located below the entire intake silencer 50 or the entire expansion chamber 51a and the upstream end 51i1, and in plan view, the entire intake silencer 50 or the expansion. The entire chamber 51a is enclosed in a U shape from the left and right directions and from the rear. Accordingly, the outside air inlet 42 opens rearward at the rear end portion of the air intake space 40.
The left and right front ends 42b, 42c of the outside air inlet 42 extend in the front-rear direction to the front of the air outlet 51o, the rotation center line Le, the air inlet 51i, the intake silencer 50, or the expansion chamber 51a. . For this reason, the outside air inlet 42 is located laterally with respect to the upstream end 51i1 in the left-right direction and the downstream end 51o of the air outlet 51o, and exceeds the arrangement range Y of the upstream end 51i1 and the downstream end 51o2 in the front-rear direction. Extending in the direction. In this way, the outside air inlet 42 is located on both sides of the upstream end 51i1 in the left-right direction and from the cylinder head 2 and the head cover 3 of the engine body to the front of the rotation center line Le of the crankshaft 8 in the front-rear direction. It is formed over the front and rear range.
For this reason, since the circumferential length, which is the circumferential length of the outside air inlet 42, which is the periphery of the air intake space 40, can be increased, the intake of the required amount of combustion air is ensured, and the outside air inlet 42 The opening width W can be reduced.

  1, 2, 5, and 12, the ceiling wall 15 b of the engine cover 15 has a shape protruding upward from the vicinity of the opening 41 or the outside air inlet 42, and the outside air inlet 42 in the left-right direction. And a pair of left and right side walls 15s and 15t (in FIG. 5, the side walls 15s and 15t are indicated by two-dot chain hatching). The air intake space 40 has a pair of left and right rising spaces 40s, 40t formed by the intermediate cover 28 and the side walls 15s, 15t and extending upward from the outside air intake 42. The rising spaces 40 s and 40 t are located between the outside air inlet 42 and the air inlet 51 i in the front-rear direction, and the air inlet 51 i in the vertical direction of the air inlet space 40 is above the rising spaces 40 s and 40 t. It communicates with the open space portion 40i.

  1 to 4, 6, and 8, the introduction part 70 that forms the introduction passage 71 that is disposed adjacent to the expansion chamber 51 a of the air suction passage 51 in the front-rear direction and the rear thereof is illustrated in FIG. A top wall 72 formed by a part of the bottom wall 73, a bottom wall 73 formed by the intermediate cover 28, and a side wall formed by the top cover 27 or the intermediate cover 28 between the top wall 72 and the bottom wall 73. 74. The side wall 74 includes a front wall 74a projecting upward from the bottom wall 73, a left wall 74c and right wall 74d projecting upward from the bottom wall 73, and a rear wall 74b projecting downward from the top wall 72. It consists of.

The introduction passage 71 is formed by the main chamber 71a, the inlet 71i provided in the rear wall 74b, opened rearward and taking outside air into the main chamber 71a, and the outflow duct 76 to form air in the main chamber 71a. And an outflow port 71o through which the air flows out to the ventilation inlet Ri. The outlet 71o is opened in the engine room R by opening in a ventilation inlet Ri provided in the ceiling wall 15b and opening in the engine room R. In other words, the ventilation inlet Ri opens to the outlet 71o that is outside the engine room R. The passage area of the main chamber 71a is larger than the passage areas of the inlet 71i and the outlet 71o.
The outflow duct 76 that is integrally formed on the bottom wall 73 that is a part of the intermediate cover 28 is an air duct that protrudes upward in the main chamber 71a and also protrudes into the ventilation inlet Ri. Intrusion of water into the inlet Ri and consequently the engine room R is suppressed. In the main chamber 71a, a shielding wall 75 made of a hanging wall formed integrally with the intermediate cover 28 is provided. Water that has entered the main chamber 71a together with air from the inlet 71o collides with the shielding wall 75, and the water enters the outlet 71o and further into the engine room R through the shielding wall 75. To suppress.
The introduction passage 71 constitutes a communication passage as an air passage for ventilation air that continuously extends outside the engine room R and inside the engine room R.

  1 to 4 and 8, a lead-out component 80 that forms a lead-out passage 81 disposed in front of the expansion chamber 51 a in the front-rear direction is a top wall 82 formed by the top cover 27. A bottom wall 83 formed by the intermediate cover 28, and a side wall 84 formed by the top cover 27 and the intermediate cover 28 between the top wall 82 and the bottom wall 83. The whole lead-out component 80, and hence the whole lead-out passage 81 including the discharge port 81o, is disposed on the opposite side of the cylinder head 2 with respect to the rotation center line Le of the crankshaft 8 in the front-rear direction. It arrange | positions ahead of Le. The side wall 84 includes a front wall 84a, a left wall 84c, and a right wall 84d that are formed by the top cover 27 and project downward from the top wall 82, and a rear wall 84b that is formed by the intermediate cover 28.

  The lead-out passage 81 is formed by the main chamber 81a, the inlet 81i that is formed by the inlet duct 85 and flows the air flowing out from the ventilation outlet 91o into the main chamber 81a, and the discharge duct 86, and the air in the main chamber 81a. And a discharge port 81o that flows out of the outboard motor S toward the rear. The inflow port 81i is also opened to the ventilation outlet 91o through the flow port 15d (see also FIG. 8) and the annular seal member 29 by opening in the flow port 15d provided in the ceiling wall 15b. The passage area of the main chamber 81a is larger than the passage areas of the inlet 81i and the outlet 81o.

A sponge-like sealing member 29 (also see FIG. 14) made of a rubber material is provided integrally with the ceiling wall 15b as a part of the engine cover 15, and is provided with a passage forming portion 15n that forms a flow port 15d, and a discharge passage. As a part of the component 90, the upper case 92b is integrally formed and disposed between the outlet duct 97 as an outlet forming portion that forms a ventilation outlet 91o. The seal member 29 forms a communication port 98 that communicates the flow port 15d immediately upstream of the inflow port 81i with the ventilation outlet 91o. Therefore, the passage forming portion 15n as the first passage part and the outlet duct 97 as the second passage part are covered with the engine cover 15 integrally coupled with the top cover 27 and the intermediate cover 28 from above the internal combustion engine E. By being coupled to the lower cover 14 (see FIG. 1), they are abutted and connected via the seal member 29.
The passage forming portion 15n and the outlet duct 97 have abutting surfaces J3 and J4 as sealing surfaces facing each other in the abutting direction K2, and the seal member 29 is in close contact with both the abutting surfaces J3 and J4, respectively. The space between 15n and the outlet duct 97 is sealed. Each butt surface J3, J4 is a plane substantially orthogonal to the butt direction K2 or the main flow of air flowing from the exhaust outlet 91o through the communication port 98 and the flow port 15d to the inflow port 81i.

  The inflow duct 85 provided integrally with the bottom wall 83, which is a part of the intermediate cover 28, is an air duct that protrudes upward in the main chamber 81a and also protrudes into the flow port 15d. Intrusion of water into the outlet 91o and thus into the discharge passage 91 is suppressed. The discharge duct 86 includes a duct 86c formed by the left wall 84c and the left wall 28c at the front of the intermediate cover 28, and a duct 86d formed by the right wall 84d and the right wall 28d at the front of the intermediate cover 28. Composed. The discharge port 81o is formed by the ducts 86c and 86d and opens to the outside air toward the rear (see also FIG. 5).

Referring to FIGS. 2, 4, and 8, the intermediate cover 28 has a frame structure formed by a protruding wall A having a double wall structure having a longitudinal section bent into a mountain shape. The frame structure includes a pair of projecting walls Ac and Ad extending in the front-rear direction, and a pair of projecting walls Aa and Ab extending in the left-right direction and intersecting the projecting walls Ac and Ad. The rigidity of the intermediate cover 28 is increased.
The side walls 54, 74, and 84 of the air intake passage 51, the introduction passage 71, and the outlet passage 81 are constituted by the protruding wall A. Specifically, the front wall 54a and the rear wall 84a are each constituted by a pair of protruding walls Aa, and similarly, the rear wall 54b and the front wall 74a are respectively constituted by a pair of protruding walls Ab. Further, the left walls 54c and 74c are constituted by the protruding wall Ac, and the right walls 54d and 74d are constituted by the protruding wall Ad. The space between the double walls of the protruding wall A is a part of the air intake space 40.
Furthermore, a convex fitting part B1 and a shielding wall 75 formed by an annular projecting part provided integrally with the top surface of the projecting wall A, and a pair of annular parts provided on the lower surface of the top cover 27. The airtightness of the air intake passage 51, the introduction passage 71, and the outlet passage 81 is enhanced by fitting with the concave fitting portion B2 formed by the protruding portion.

  Referring to FIGS. 1 to 3 and 9, the intake air that is disposed in the engine room R and forms the intake passage that guides the combustion air in the air intake passage 51 to the combustion chamber 22 through the intake port. The device 30 includes a downstream intake silencer 60 disposed above the engine body, and a throttle valve 31a connected to the intake silencer 60 for controlling the amount of air and disposed above the engine body. A device 31 and an intake manifold 32 as an intake pipe connected to the throttle valve device 31 are provided. The intake silencer 50 and the intake silencer 60 are arranged so as to overlap in the vertical direction, and the intake silencer 50 is an upper intake silencer disposed above the intake silencer 60 as a lower intake silencer.

The intake passage, which is a continuous passage that is not interrupted in the engine room R from the intake inlet 61i to the intake port, includes an upstream intake passage 61 formed by the intake silencer 60, and a throttle body provided in the throttle valve device 31. And a downstream intake passage 34 that is formed by the intake manifold 32 and communicates with the upstream intake passage 61 via the throttle passage 33. Air in the downstream intake passage 34 flows out from the outlet of the intake passage to the intake port, and is sucked into the combustion chamber 22 from the intake port. The throttle passage 33 extends in the front-rear direction or along the straight line La (see FIG. 11) in plan view. In this embodiment, the straight line La passes through the rotation center line Le and is parallel to the front-rear direction in plan view.
The air intake space 40, the air intake passage 51 having the intake port 51o, the flow port 15c, the communication port 141, and the intake passage having the intake port 61i are connected to the outside of the engine room R and the engine room R. A communication passage is formed as an air passage for the combustion air continuously extending inward.

  Referring to FIGS. 2, 3 and 8, the intake silencer 60 includes a lower case 60a as a first case that covers the transmission mechanism 24 from above, and a second case that is airtightly coupled to the lower case 60a by screws. And an upper case 60b. After the discharge passage component 90 is attached to the engine body, the cylinder block 1, the cylinder head 2, and the head cover 3 are set at a plurality of attachment portions that are set at the attachment position from the rear in the front-rear direction and provided in the lower case 60a. Removably attached to each upper end.

The intake silencer 60 includes a chamber wall 66 that forms an expansion chamber 61a, an inlet duct 62 that forms an intake inlet 61i, and an outlet duct 63 that forms an intake outlet 61o. The chamber wall 66, the inlet duct 62, and the outlet duct 63 constitute a passage wall of the upstream side intake passage 61. The chamber wall 66 includes an upper chamber wall 66a to which the inlet duct 62 is integrally formed and connected, and a lower chamber wall 66b to which the outlet duct 63 is integrally connected and coupled to the lower end portion of the upper chamber wall 66a. Consists of
The inlet duct 62 and the intake inlet 61i extend in parallel in the vertical direction, and the outlet duct 63 and the intake outlet 61o extend in parallel in the front-rear direction.

The top wall 67 of the upper chamber wall 66a includes a lower high wall portion 67a that overlaps with the second high wall portion 53a2 of the bottom wall 53 of the upper expansion chamber 51a in plan view, and a first high wall portion of the bottom wall 53 in plan view. It is a step-shaped wall having a lower low wall portion 67b that overlaps 53a1 and is positioned below the high wall portion 67a. The inlet duct 62 and the intake inlet 61i are disposed in the low wall portion 67b, and the outlet duct 63 and the intake outlet 61o are disposed below the high wall portion 67a in a plan view and overlap with the high wall portion 67a. The
The intake silencer 50 and the intake silencer 60 are arranged such that the intake silencer 50 is directly above the ceiling wall 15b and the intake silencer 60 is directly below the ceiling wall 15b with the ceiling wall 15b interposed therebetween. The raised portion 15p has a second high wall at a position overlapping the second high wall portion 53a2 and the first high wall portion 53a1 of the bottom wall 53 and the high wall portion 67a and the low wall portion 67b of the top wall 67 in plan view. It protrudes upward in a shape along the portion 53a2, the first high wall portion 53a1, the high wall portion 67a, and the low wall portion 67b. The raised portion 15p disposed between the high wall portion 53a and the top wall 67 in the vertical direction is located behind the air introduction port 51i.

  The upstream intake passage 61 is formed by an expansion chamber 61a that is an intake silencer chamber as an expansion chamber, and an inlet duct 62, and intake air that causes the air in the air intake space 40 to flow into the expansion chamber 61a of the upstream intake passage 61. It has an inlet 61i and an intake outlet 61o that is formed by the outlet duct 63 and allows the air in the expansion chamber 61a to flow out into the throttle passage 33. The passage areas of the downstream expansion chamber 61a through which combustion air from the intake silencers 50 and 60 flows through the intake inlet 61i are larger than the respective passage areas of the intake inlet 61i and the outlet 61o. The intake inlet 61i communicates directly with the air intake passage 51 outside the engine room R without communicating with the engine room R. In the expansion chamber 61a, upstream of the intake outlet 61o, a frame trap 64 made of a metal mesh that performs a flame extinguishing function when a backfire occurs is disposed.

  Referring to FIGS. 1 to 3, the ventilator uses an introduction component 70 that guides outside air into the engine room R, and air in the engine room R heated by heat radiation from the internal combustion engine E and the like to increase the temperature in the engine room R. A discharge passage component 90 that forms a discharge passage 91 that discharges from the inside to the outside of the engine room R, and a lead-out component 80 that guides the air that has flowed out of the discharge passage component 90 to the outside of the outboard motor S are configured.

  In the introduction passage 71 arranged outside the engine room R, the ventilation air flowing into the engine room R from the ventilation inlet Ri opening to the outlet 71o is integrally formed in the upper case 60b of the intake silencer 60. Are guided to the rear of the intake manifold 32, the head cover 3 and the cylinder head 2 along the guide plate 65 which is a guide member, and thereafter, the intake device 30, the head cover 3, the cylinder head 2, the cylinder block 1 and the crankcase portion 4, etc. After being cooled, a part thereof is sucked as cooling air into the generator G attached to the crankcase portion 4 constituting the front end portion of the engine body via the bracket 4a (see FIG. 2). Ventilation air flowing in from the ventilation inlet Ri cools the cylinder head 2 and the cylinder block 1 forming the combustion space at a lower temperature in the process of flowing from the rear of the engine body toward the front of the engine body. It is efficiently used as cooling air. Moreover, since the guide plate 65 is integrally formed with the intake silencer 60, the number of parts is reduced.

  Referring to FIGS. 1 to 3, 9, and 13 to 15, a discharge passage component 90 that covers the transmission mechanism 25 from above is airtightly coupled to the lower case 92 a as a first case and the lower case 92 a by screws. As a blowing means arranged in a discharge path 91 formed by a case 92 composed of an upper case 92b as a second case, and a lower case 92a and an upper case 92b, and pressure-feeds air toward the outlet passage 81 And a ventilation fan 93 composed of a centrifugal fan. The discharge passage component 90 is set at a mounting position from the front in the front-rear direction, and is attachable to and detachable from each upper end portion of the cylinder block 1 and the crankcase portion 4 at a plurality of mounting portions F provided on the case 92 and a cover 111 described later. Attached to.

The exhaust passage 91 disposed in the engine room R includes an inlet 91i disposed in the upper end space Ra of the engine room R and opening upward, a ventilation outlet 91o opening to the inlet 81i of the outlet passage 81, It has an outflow passage 91c that guides the air pumped by the fan 93 after flowing in from the inflow port 91i to the ventilation outlet 91o. The upper end space Ra is a space portion formed along the ceiling wall 15b in the vicinity of the lower side of the ceiling wall 15b in the engine room R, and is higher than the upper end portion of the crankshaft 8, the generator G, and the transmission mechanisms 24 and 25. Located above. The fan 93 having a large number of blades 93a is coupled to the upper part of the fan 93 by bolts (not shown) so as to rotate integrally with the drive pulley 25a, and is therefore provided at the upper end of the crankshaft 8. In plan view, the fan 93 is disposed at a position overlapping the air inlet 51i in a part near the ventilation outlet 91o in the front-rear direction.
The inlet 91i and the ventilation outlet 91o are provided in the upper case 92b. An inflow port 91i that forms an air gap in the vertical direction on the ceiling wall 15b and is opposed to the inflow port 91i is disposed above the crankcase where the air for ventilation that has become hot after the cylinder head 2 and the cylinder block 1 are easily collected. . The relatively hot air in the engine room R, that is, the air after cooling the engine body and the air after cooling the generator G flow into the inflow port 91i.
The outflow passage 91c and the outlet passage 81 of the discharge passage 91 are arranged at the same position as the generator G in the front-rear direction, and the outflow passage 91c and the outlet passage 81 are arranged at a position overlapping the generator G in plan view. .
A discharge passage 91 having a ventilation outlet 91o, a communication port 98, a circulation port 15d, and a lead-out passage 81 having an inflow port 81i are used for discharging the air in the engine room R to the outside of the outboard motor S. It is a passage and constitutes a communication passage as an air passage for ventilation air continuously extending over the outside of the engine room R and the inside of the engine room R.

Referring to FIGS. 2 to 5 and 11, in the front-rear direction, the intake outlet 61 o is disposed on the opposite side of the air inlet 51 i with respect to the air outlet 51 o and the intake inlet 61 i. The air outlet 51o, the intake inlet 61i, and the intake outlet 61o are arranged so as to intersect with one straight line La that intersects the air inlet 51i and the throttle passage 33 in a plan view.
In plan view, the inlet 71i, the outlet 71o and the ventilation inlet Ri, the outlet 51o and the intake inlet 61i, the intake outlet 61o, the air inlet 51i, the ventilation outlet 91o and the inlet 81i are arranged from the rear. In order, they are arranged in a straight line in an arrangement direction parallel to the front-rear direction. The intake port 51i is disposed in front of the intake port 51o and the intake port 61i. In the arrangement direction, the inlet 71i, the outlet 71o, the ventilation inlet Ri, the air outlet 51o, and the intake inlet 61i are arranged behind the rotation center line Le and closer to the cylinder head 2, and the air inlet The 51i, the ventilation outlet 91o, the inlet 81i, and the outlet 81o are disposed in front of the crank chamber 5 with respect to the rotation center line Le. The top cover 27 covers the outlet 71o, the air outlet 51o, the air inlet 51i, and the inlet 81i from above.

  Further, in a plan view, the discharge passage component 90 is disposed closer to the rotation center line Le on the side opposite to the inlet 71i, the outlet 71o, and the ventilation inlet Ri with respect to the intake silencer 60. Most of the discharge passage component 90 is disposed forward or closer to the rotation center line Le than the intake port 51o and the intake port 61i. Therefore, in the front-rear direction, the intake silencer 60 is disposed on the cylinder head 2 side or on the rear part of the outboard motor S or the engine body, and the discharge passage component 90 is disposed on the crank chamber 5 side (that is, the crankcase side), Or it is arrange | positioned in the front part of the outboard motor S or an engine main body.

  In addition, since the intake silencer 60 and the exhaust passage component 90 are separate members, and the engine cover 15 is also a separate member, there is less restriction on the shape thereof. For example, in the intake silencer 60, the distance between the intake inlet 61i and the intake outlet 61o can be shortened, and the intake efficiency can be improved. Further, with respect to the intake silencer 60 disposed in the region where the relatively low temperature air exists in the engine room R, the relatively high temperature air after the cylinder head 2 and the cylinder block 1 are cooled in the engine room R. Since the discharge passage part 90 can be disposed in the region where the air is present, and the distance between the inlet 91i and the ventilation outlet 91o can be shortened, the ventilation efficiency can be improved.

  1 to 3 and 8, the generator G includes a rotating shaft 101 (see FIGS. 3 and 13) that is rotationally driven by the power of the crankshaft 8 that is transmitted via the transmission mechanism 25, and And a housing 102 that houses a rotor that rotates integrally with the rotating shaft 101. The rotor is provided with a cooling fan (not shown) that sucks air into the housing 102. Air that is sucked by the cooling fan and cools the inside of the generator G is sucked into the housing 102 and flows in. An inlet 103 and an outlet 104 through which cooled air flows out as exhaust air are provided.

Referring to FIGS. 1 to 3 and FIGS. 13 to 15, in the engine room R, around the generator G, exhaust air which is air flowing into the generator G and air after cooling the generator G A wind guide part D for guiding the air to the inflow port 91i is arranged. The air guide part D and the discharge passage part 90 are integrated with each other to constitute a wind exhaust part which is one part.
The wind guide component D is arranged around the inlet 103 and the outlet 104 and surrounds the housing 102, and the wind guide space 113 formed by the wind guide cover 111 and the housing 102 (see FIG. 2). And a guide wall 121 as a guide part for guiding the exhaust air flowing out from the outlet 104 to the inlet 91i of the discharge passage 91. The air guide cover 111 and the guide wall 121 are integrally formed and are formed integrally with the lower case 92a.
The wind guide cover 111 extends in the generator axial direction parallel to the rotation center line Lg of the rotating shaft 101 of the generator G and in the generator circumferential direction centering on the rotation center line Lg, and extends the housing 102 from the front and left and right directions. It has a surrounding peripheral part 111a, a ceiling part 111b connected to the upper end part of the peripheral part 111a, and a bottom part 111c connected to the lower end part of the peripheral part 111a.
An air inlet 112 composed of a number of slits for allowing the air in the engine room R to flow into the air guide space 113 in the cover 111 is provided at the upper part of the peripheral portion 111a. The ceiling portion 111b is constituted by a passage wall that forms the outflow passage 91c.
The bottom part 111c is constituted by a plate-like member provided by being coupled to the lower end part of the cover 111 with a screw.
The exhaust air flowing out from the outflow port 104 is prevented from flowing out from the air guiding space 113 by the ceiling portion 111b, and is prevented from flowing out from the air guiding space 113 by the bottom portion 111c. Led to 114. Further, as shown in FIGS. 9, 11, and 13, the cooling air that has flowed into the air guide space 113 from the air inlet 112 is sucked into the fan 93 from the air guide space 113. And a pair of shielding walls 95 and 96 for preventing the exhaust air from the outlet 104 from being directly sucked into the fan 93 from the air guiding space 113 without passing through the air outlet 114. Provided. Therefore, the ceiling portion 111b, the bottom portion 111c, and the shielding walls 95 and 96 can efficiently exhaust the exhaust air in the air guide space 113 from the exhaust port 114.

  Referring also to FIG. 16, the rotation direction of the rotating shaft 101 of the generator G (clockwise in FIG. 3) is the same position as the rear part of the generator G in the front-rear direction and laterally below the periphery of the cover 111. In a portion having a component in which the tangent line in the direction) faces backward, exhaust air in the air guide space 113 is guided in the engine room R by the cooperation of the guide wall 121 and the engine cover 15. In this embodiment, the passage 129 is provided with an exhaust port 114 for flowing out toward the rear, which is a direction approaching the inflow port 91i disposed behind the generator G, in a direction approaching the inflow port 91i.

  The guide wall 121 has an inclined wall 122 inclined obliquely upward to deflect the exhaust air from the exhaust port 114 toward the inflow port 91i disposed above the exhaust port 114, and the exhaust air of the guide passage 129. Are deflected toward the rotation center line Le that is the rotation center line of the fan 93 and the inflow port 91i. The exhaust air deflected by the deflecting wall 123 is guided to a deflecting wall 94 that is integrally formed with the upper case 92b and protrudes upward, and flows into the inflow port 91i. The ceiling wall 15b has a deflection wall 15h (see FIGS. 3, 9, and 13) that hangs down so as to face both the deflection walls 123 and 94 in the vertical direction. In FIG. The wall 15h is offset from the deflecting walls 123 and 94), and a cover wall 15k that covers the inlet 91i from above is integrally formed. The deflecting wall 15h efficiently guides exhaust air from the exhaust port 114 to the inflow port 91i and prevents air other than the exhaust air in the engine room R from heading toward the inflow port 91i. Is prevented. Further, the covering wall 15k, which is a portion protruding upward in the ceiling wall 15b, covers a portion near the guide passage 129 of the inflow port 91i within a range of half or less of the opening area of the inflow port 91i in plan view (FIG. 4). , And FIG. 13) and the portion near the inlet 91i in the guide passage 129 is covered from above.

Next, operations and effects of the embodiment configured as described above will be described.
In the outboard motor S including the internal combustion engine E in which the combustion chamber 22 is formed, the upper intake silencer 50 into which combustion air flows and the lower intake silencer that guides the combustion air from the intake silencer 50 to the combustion chamber 22. The intake air silencer 50 disposed above and below the intake silencer 60 is provided with an air inlet 51i, an expansion chamber 51a, and an air outlet 51o. The intake silencer 60 is provided with an intake inlet 61i connected to the air outlet 51o, an expansion chamber 61a, and an intake outlet 61o. The bottom wall 53 of the expansion chamber 51a is connected to the intake silencer 60 in a plan view. It is a stepped wall having an overlapping high wall portion 53a and an upper low wall portion 53b positioned below the high wall portion 53a without overlapping the intake silencer 60 in plan view. It arrange | positions at the wall part 53a.
With this structure, the low wall portion 53b of the bottom wall 53 formed in a step shape in the intake silencer 50 does not overlap the intake silencer 60, so that the low wall portion 53b can be disposed below, so that the expansion chamber 51a The volume can be increased, and the intake noise reduction effect by the intake silencer 50 can be enhanced.
Further, the high wall portion 53a provided with the air outlet 51o connected to the intake inlet 61i of the intake silencer 60 is disposed directly above the intake silencer 60, so that it is formed below the high wall portion 53a. An intake silencer 60 is arranged in the space to be used. As a result, the bottom wall 53 having the high wall portion 53a and the low wall portion 53b is connected to the air outlet 51o and the intake inlet 61i by using the high wall portion 53a that overlaps the intake silencer 60 in plan view. However, since both intake silencers 50, 60 can be arranged close to each other in the vertical direction, both intake silencers 50, 60 can be arranged compactly in the vertical direction, and the outboard motor S is small in the vertical direction. Can be

The top wall 67 of the intake silencer 60 has a stepped wall having a high wall portion 67a and a low wall portion 67b that overlaps the bottom wall 53 of the expansion chamber 51a in plan view and is positioned below the high wall portion 67a. Since the intake inlet 61i is disposed in the low wall portion 67b, the high wall portion 67a of the top wall 67 formed in the step shape in the intake silencer 60 is disposed above the low wall portion 67b. Therefore, the volume of the expansion chamber 61a can be increased, and the intake noise reduction effect by the intake silencer 60 can be enhanced.
Further, the low wall portion 67b provided with the intake inlet 61i connected to the air outlet 51o of the intake silencer 50 is disposed directly below the intake silencer 50, so that it is formed above the low wall portion 67b. An intake silencer 50 is arranged in the space to be used. As a result, the air outlet 51o and the inlet 61i are connected by using the lower wall 67b that overlaps the intake silencer 50 in a plan view on the top wall 67 having the high wall 67a and the low wall 67b. However, since both intake silencers 50, 60 can be arranged close to each other in the vertical direction, both intake silencers 50, 60 can be arranged compactly in the vertical direction, and the outboard motor S is small in the vertical direction. Can be

The intake inlet 61i is disposed in the lower wall portion 67b of the top wall 67 of the intake silencer 60, so that the bottom wall 53 of the intake silencer 50 and the top wall 67 of the intake silencer 60 are complementary to each other. Therefore, the low wall portion 53b of the bottom wall 53 of the intake silencer 50 does not overlap the intake silencer 60 in a plan view, and the high wall portion 67a of the top wall 67 of the intake silencer 60 is By disposing above the low wall portion 67b, the volumes of the expansion chambers 51a and 61a can be increased, respectively, and the intake noise reduction effect by the intake silencers 50 and 60 can be enhanced. .
Further, the low wall portion 67b provided with the intake inlet 61i is disposed directly below the first high wall portion 53a1 provided with the air outlet port 51o, thereby forming a space formed below the first high wall portion 53a1. The low wall portion 67b positioned below the high wall portion 67a is disposed. As a result, by using the first high wall portion 53a1 and the low wall portion 67b that overlap each other in plan view in both the intake silencers 50, 60, the both intake silencers are connected while the air outlet 51o and the intake inlet 61i are connected. Since 50 and 60 can be arranged close to each other in the vertical direction, both intake silencers 50 and 60 can be arranged compactly in the vertical direction, and the outboard motor S can be downsized in the vertical direction.

  The intake silencer 50 and the intake silencer 60 are disposed with the ceiling wall 15b of the engine cover 15 interposed therebetween, and the intake silencer 50 covers the engine cover 15 and the engine cover 15 from above and outside the engine room R. Arranged in the air intake space 40 formed by the top cover 27 and the intake silencer 60 in the engine room R, the intake silencer 50 and the intake silencer 60 are placed outside the engine room R and Since the intake silencer 50 is arranged using the air intake space 40 in the engine room R, the engine cover 15 and the outboard motor S can be downsized. In addition, since the engine cover 15 is downsized, the vibration of the engine cover 15 due to the intake pulsation attenuated by the both intake silencers 50 and 60 is further suppressed, so that the noise caused by the vibration of the engine cover 15 due to the intake pulsation Is reduced.

  In the outboard motor S on which the power unit P is mounted, the intake device 30 includes an intake silencer 60 that forms an upstream intake passage 61 having an intake inlet 61i that opens to the outside of the engine room R. And an exhaust passage component 90 that forms an exhaust passage 91 having a ventilation outlet 91o that opens to the outside of the engine room R. The intake passage component 60 and the exhaust passage component 90 are separate from each other and the engine cover 15 By being a separate part and disposed in the engine room R, the intake silencer 60 and the exhaust passage part 90 are separate independent parts and separate parts from the engine cover 15. Heat transfer between the combustion air in the intake passage including the intake passage 61 and the air in the exhaust passage 91 is suppressed to improve charging efficiency, and the intake silencer 60 in the engine room R is improved. In addition, since the mutual restrictions on the arrangement of the discharge passage parts 90 are reduced and the degree of freedom of the arrangement of the two passage parts 60, 90 is increased, the shape of each of the two passage parts 60, 90 can be optimized. Since it can form, it contributes to the improvement of intake efficiency and ventilation efficiency.

  A ventilation inlet Ri that opens to the outside of the engine room R is provided in the engine cover 15, and when viewed from the direction of the rotation center line Le of the crankshaft 8, the arrangement direction (or front-rear direction) of the ventilation inlet Ri and the ventilation outlet 91o , The ventilation inlet Ri is disposed closer to the cylinder head 2 with respect to the rotation center line Le, and the exhaust passage component 90 is disposed closer to the rotation center line Le on the side opposite to the ventilation inlet Ri with respect to the intake silencer 60. As a result, the ventilation air that has flowed into the engine room R from the ventilation inlet Ri disposed near the cylinder head 2 is a cylinder that is a relatively hot part in order to form a combustion space in the engine body of the internal combustion engine E. A discharge passage 91 formed by a discharge passage component 90 disposed near the rotation center line Le of the crankshaft 8 after the head 2 and the cylinder block 1 are cooled. Since it flows in, relatively high-temperature air in the engine room R can be efficiently discharged to the outside of the engine room R, and the ventilation efficiency is improved while improving the cooling performance of the internal combustion engine E by the ventilation air. Can do.

  The valve gear 23 of the internal combustion engine E includes a camshaft 23a that is rotationally driven by the power of the crankshaft 8 transmitted through the transmission mechanism 24, and the intake silencer 60 and the exhaust passage component 90 are arranged in the front-rear direction. The belt cover divided into two in the front-rear direction is configured by covering the transmission mechanism 24 from above. Thereby, since the belt cover is configured by the intake silencer 60 and the discharge passage component 90 divided in the front-rear direction, the intake silencer 60 from the opposite direction in the front-rear direction, specifically from the rear, and When the belt cover is constituted by the intake silencer 60 and the discharge passage part 90, it becomes possible to attach and detach the discharge passage part 90 from the front, and attachment of the belt cover to cover the transmission mechanism 24 Becomes easier.

The outboard motor S includes an intermediate cover 28 disposed between the engine cover 15 and the top cover 27 in the vertical direction, and first coupling portions 15e and 28e that couple the engine cover 15 and the intermediate cover 28 are provided with an engine. The second coupling portions 27f and 28f that are arranged between the cover 15 and the intermediate cover 28 and couple the intermediate cover 28 and the top cover 27 are arranged between the top cover 27 and the intermediate cover 28, Both are coupled by coupling portions 15e and 28e disposed in the space between the engine cover 15 and the intermediate cover 28, and both are coupled by coupling portions 27f and 28f disposed in the space between the top cover 27 and the intermediate cover 28. Therefore, the engine cover 15 and the top cover 27 are coupled via the intermediate cover 28. Since the intermediate cover 28 is disposed between the engine cover 15 and the top cover 27 in the vertical direction, the interval or space between the engine cover 15 and the top cover 27 is divided by the intermediate cover 28, and the engine cover 15 and the intermediate cover 28 and the distance between the top cover 27 and the intermediate cover 28 are smaller than the distance between the engine cover 15 and the top cover 27, so that the height of the coupling portions 15e and 28e and the coupling portions 27f and 28f. Becomes smaller. As a result, it becomes easy to ensure the required rigidity of the coupling portions 15e and 28e and the coupling portions 27f and 28f. In addition, since the restriction due to the distance between the engine cover 15 and the top cover 27 is reduced and the degree of freedom of arrangement of the coupling portions 15e, 28e and the coupling portions 27f, 28f is increased, When the air intake space 40, the air intake passage 51, the introduction passage 71, and the discharge passage 81 are formed between the cover 15 and the top cover 27, the rigidity of the engine cover 15 and the top cover 27 is increased, and the grip In each case such as a case where the load acting on the engine cover 15 is distributed through the top cover 27 when the portion 130 is gripped, the coupling portions 15e and 28e and the coupling portions 27f and 28f can be arranged at optimum positions. .
In addition, since it is not necessary to increase the size of the engine cover 15 in the vertical direction in order to ensure the rigidity of the connecting portion that connects the engine cover 15 and the top cover 27, an increase in the size of the mold for manufacturing the engine cover 15 is avoided. Thus, the manufacturing cost of the engine cover 15 is reduced.

  The intermediate cover 28 is an air duct that forms an inlet 51i, an outlet 51o, an outlet 71o, and an inlet 81i, which are part of an air passage extending outside the engine room R and inside the engine room R, respectively. The ducts 55, 56, 76, 85 are in the air intake passage 51, the duct 76 is in the introduction passage 71, and the duct 85 is in the discharge passage 81, respectively. By projecting, ducts 55, 56, 76, 85 that can be prevented from entering water by projecting upward in each passage 51, 71, 81 are provided in the intermediate cover 28. Compared with the case where such an air duct is provided, the shape of the engine cover 15 is simplified, and the manufacturing cost of the engine cover 15 is reduced.

  The air intake passage 51 has an intake silencer chamber 51a through which combustion air sucked into the internal combustion engine E flows. The intermediate cover 28 and the top cover 27 form an intake silencer chamber 51a, whereby the intake silencer chamber 51a. Compared to the case where the engine cover 15 is formed, the shape of the engine cover 15 is simplified, and the manufacturing cost of the engine cover 15 is reduced. In addition, since the intake silencing chamber 51a is separated from the engine room R where the air heated by the internal combustion engine E exists by the distance between the engine cover 15 and the intermediate cover 28 or the air intake space 40, The combustion air in the muffler chamber is suppressed from being heated by the heat from the engine cover 15, and the charging efficiency of the internal combustion engine E is improved.

  The introduction passage 71 is a passage through which ventilation air for ventilating the inside of the engine cover 15 is introduced into the engine room R. The intermediate cover 28 and the top cover 27 form the introduction passage 71, whereby the engine cover 15 Is separated from the engine room R where the air heated by the internal combustion engine E exists by the distance between the intermediate cover 28 and the air intake space 40, so that the ventilation air is heated by the heat from the engine cover 15. It is suppressed, and the cooling effect of the engine by the ventilation air is improved.

  Between the passage forming portion 15m and the inlet duct 62, which are connected to each other to form the inlet 15c and the inlet port 61i, which are part of the communication passage extending outside the engine room R and inside the engine room R. The disposed seal member 140 includes a lip 142 that is in close contact with the abutting surface J1 of the passage forming portion 15m, a flexible portion 144 that is elastically deformed into a bent shape when the lip 142 is pressed by the abutting surface J1, and a communication port 141. And a working surface 145 on which an intake negative pressure, which is a pressure of combustion air as a gas flowing through the communication port 141, acts, and the working surface 145 has a lip 142 in close contact with the abutting surface J1. At the same time, before the intake negative pressure acts on the working surface 145, it has a facing surface 145a facing the butting surface J1 in the acting direction of the intake negative pressure, and the lip 142 is applied by the action of the intake negative pressure on the facing surface 145a. The urging force to press against the butt surface J1 Jill. Thereby, when the lip 142 is pressed by the abutting surface J1, the flexible portion 144 is elastically deformed into a bent shape, so that the connection between the passage forming portion 15m and the inlet duct 62 via the seal member 140 is intermediate. The passage forming portion 15m which is a part of the cover 28 and the inlet duct 62 which is a part of the intake silencer 60 are easily connected, and the workability of the connection work is improved. In addition, since the biasing force generated by the intake negative pressure acting on the opposing surface 145a presses the lip 142 against the abutting surface J1, the seal pressure by the lip 142 is obtained by using the intake negative pressure of the air flowing through the communication port 141. Can be increased, and the sealing performance is improved.

  Before the intake negative pressure of the combustion air sucked into the internal combustion engine E acts on the action surface 145, between the abutting surface J1 and the opposite surface 145a in the action direction of the intake negative pressure on the opposite surface 145a, Since the space 141a which is a part of the communication port 141 is formed, the urging force generated by the intake negative pressure acting on the opposing surface 145a presses the lip 142 against the abutting surface J1, so that the communication port 141 is circulated. By utilizing the intake negative pressure of the combustion air, the sealing pressure by the lip 142 can be increased, and the sealing performance is improved. In addition, the opposing surface 145a having a larger area can be formed by utilizing the space 141a formed by bending the flexible portion 144 of the seal member 140.

  The sealing member 140 is provided with a hollow portion 146, the lip 142 has flexibility, and the flexible portion 144 has a thin portion 144a formed by providing the hollow portion 146. Since the seal portion in close contact with J1 is constituted by the flexible lip 142, deformation at the seal portion is facilitated, which contributes to improvement in workability of connection work. Moreover, since the flexible portion 144 is formed by the thin-walled portion 144a formed by providing the hollow portion 146 in the seal member 140, the flexible portion 144 can be easily formed. Further, in the connection state in which the flexible portion 144 is bent, the volume of the hollow portion 146 is reduced as compared with that before the bending of the flexible portion 144. Therefore, the pressure of the filling gas filled in the hollow portion 146 causes the lip 142 to move. By being pressed against the abutting surface J1, the sealing performance of the sealing member 140 is improved.

An engine cover 15 that forms an engine room R in which an internal combustion engine E is provided that includes an intake device 30 that guides combustion air to a combustion chamber 22 formed in the engine body; a top cover 27 that covers the engine cover 15 from above; In the outboard motor S including the intermediate cover 28 and the intake silencer 50 that leads the intake air 30 disposed in the engine room R using the outside air taken in from the outside air intake 42 as combustion air, the intake silencer 50 includes: The air intake silencer 50 is disposed outside the engine room R and spaced apart from the engine cover 15 so that an air intake space 40 having an outside air inlet 42 is formed between the engine room R and the engine cover 15. , An air introduction port 51i into which combustion air in the air intake space 40 flows, and an introduction duct 55 which is separated from the engine cover 15, and an expansion chamber into which combustion air from the air introduction port 51i flows A chamber wall 57 that forms 51a and a lead-out duct 56 that forms an air lead-out port 51o through which combustion air from the expansion chamber 51a flows out to the intake device 30, and the upstream end 51i1 of the air inlet 51i is air Opening into the intake space 40, the outside air inlet 42 is located below the upstream end port 51i1, and surrounds the intake silencer 50 or the expansion chamber 51a from the left and right directions and from the rear in plan view.
With this structure, the intake pulsation from the intake device 30 in the engine room R is attenuated by the intake silencer 50 disposed outside the engine room R, and the intake silencer 50 is separated from the engine cover 15 by the air intake space 40. As a result, the intake air pulsation transmitted from the intake device 30 to the air intake space 40 is suppressed, and noise caused by the vibration of the engine cover 15 that forms the air intake space 40 is reduced. .
Further, since the outside air inlet 42 surrounds the intake silencer 50 or the expansion chamber 51a in the rear and left and right directions in a plan view, the perimeter can be increased, and the outside air as combustion air is required. Since the opening width W of the outside air inlet 42 can be reduced while securing the amount of intake, the effect of suppressing the intrusion of water and foreign matter from the outside air inlet 42 is enhanced.
Further, since the outside air inlet 42 is located below the upstream end 51i1 and the introduction duct 55 is separated from the engine cover 15, the outside duct 42 differs from the case where the introduction duct 55 protrudes upward from the engine cover 15. In order to ensure good drainage from the air intake space 40, the restriction of the introduction duct 55 on the shape of the ceiling wall 15b, which is a forming wall forming the air intake space 40, of the engine cover 15 is reduced. The degree of freedom in designing the shape of the ceiling wall 15b increases.

  Since the downstream end port 51o2 of the air outlet port 51o is arranged behind the upstream end port 51i1 of the air introduction port 51i, the upstream end port 51i1 is positioned in front of the downstream end port 51o2 in the air intake space 40. Water that has entered the air intake space 40 from the rear is less likely to enter the upstream end 51i1, and water intrusion into the intake silencer 50 is suppressed.

The chamber wall 57 has a bottom wall 53 that faces the engine cover 15 across the air intake space 40 in the vertical direction, and the introduction duct 55 does not protrude downward from the bottom wall 53 and is bottomed in the expansion chamber 51a. Since the introduction duct 55 protrudes upward in the expansion chamber 51a by protruding upward from the wall 53, water intrusion from the air introduction port 51i is suppressed. Intrusion ducts protrude upward in the expansion chamber, allowing the intake silencer 50 to be close to the engine cover 15 in the vertical direction, and downsizing the outboard motor S in the vertical direction. it can.
Further, since the introduction duct 55 does not protrude downward from the bottom wall 53, the bottom wall 53 can be brought closer to the engine cover 15 in the vertical direction in the vicinity of the air introduction port 51i. Thus, the volume of the expansion chamber 51a can be increased without increasing the position of the intake silencer 50. As a result, the effect of reducing the intake noise can be improved by increasing the volume of the expansion chamber 51a while downsizing the outboard motor S in the vertical direction.

  The engine cover 15 has side walls 15s and 15t facing the outside air inlet 42 in the left-right direction, and the air intake space 40 is formed by the intermediate cover 28 and the side walls 15s and 15t and is upward from the outside air inlet 42. The rising spaces 40s and 40t extend between the outside air inlet 42 and the air inlet 51i in the left-right direction, and the rising spaces 40s and 40t By communicating with the space portion 4i of the intake space 40 where the air inlet 51i opens in the vertical direction, the water that has entered the air intake space 40 from the outside air inlet 42 in the left-right direction hits the side walls 15s and 15t. Since it adheres to the side walls 15s and 15t, the amount of water moving upward in the rising spaces 40s and 40t is reduced, so that the entry of water into the intake silencer 50 is suppressed.

  The outside air inlet 42 is in the left-right direction with respect to the upstream end port 51i1 of the air introduction port 51i and the downstream end port 51o2 of the air outlet port 51o, and extends in the front-rear direction beyond the arrangement range Y of the upstream end port 51i1 and downstream end port 51o2 in the front-rear direction. By extending the length, the length of the outside air inlet 42 in the front-rear direction can be increased, so that the opening width W of the outside air inlet 42 can be reduced, and entry of water and foreign matter can be suppressed.

  The upstream end port 51i1 of the air inlet port 51i and the downstream end port 51o2 of the air outlet port 51o are spaced apart from each other in the front-rear direction and are distributed in the front-rear direction with respect to the rotation center line Le of the crankshaft 8, thereby Since the length in the front-rear direction of the intake 42 can be increased, the opening width of the outside air intake 42 can be reduced, and the intrusion of water and foreign matter can be suppressed.

An engine cover 15 that forms an engine room R that houses an internal combustion engine E that includes an intake device 30 that guides combustion air to a combustion chamber 22 formed in the engine body, a top cover 27 that covers the engine cover 15 from above, and an intermediate cover In the outboard motor S including the cover 28, the engine cover 15, the top cover 27, and the intermediate cover 28 form an air intake space 40 having an external air intake 42 for taking in external air as combustion air, and the air intake space. 40, the upstream end ports 51i1 and 61i1 into which combustion air in the air intake space 40 flows, and the combustion air that flows in from the upstream end ports 51i1 and 61i1 flow out to the intake device 30 arranged in the engine room R. The downstream end ports 51i2 and 61i2 are provided, and an intake silencer 50 as an air suction component is arranged. The outside air intake 42 is located on both sides in the left-right direction and the cylinder head in the front-rear direction with respect to the upstream end port 51i1. It is formed over the front and rear range to the front than the rotation axis Le of 2 and the crank shaft 8 from the head cover 3.
With this structure, the intake silencer 50 is interposed between the intake device 30 in the engine room R and the air intake space 40, so that intake pulsation transmitted from the intake device 30 to the air intake space 40 is suppressed. Thus, noise caused by vibration of the engine cover 15 forming the air intake space 40 is reduced.
The outside air inlet 42 is formed on both sides in the left-right direction with respect to the upstream end port 51i1 and in the front-rear direction over the front-rear range from the cylinder head 2 and the head cover 3 to the front of the rotation center line Le. Therefore, since the length of the outside air inlet 42 in the front-rear direction can be increased, the opening width of the outside air inlet 42 can be reduced while ensuring the intake of the required amount of outside air as combustion air. The effect of suppressing the intrusion of water and foreign matter can be enhanced, and the intrusion of water into the intake silencer 50 through the upstream end 51i1 and thus into the combustion air can be effectively suppressed.

The outside air inlet 42 opens rearward at the rear portion of the air intake space 40, and the downstream end ports 51i2 and 61i2 are disposed rearward of the upstream end ports 51i1 and 61i1, so that the intake silencer is provided in the air intake space 40. Since the upstream end ports 51i1 and 61i1 of the 50 are positioned in front of the downstream end ports 51i2 and 61i2, the water that has entered the air intake space 40 from the rear is less likely to enter the upstream end ports 51i1 and 61i1, and the intake silencer 50 Intrusion of water is suppressed.
Further, since water that has entered the air intake space 40 is drained from the air intake space 40 in the left-right direction, water enters the intake silencer 50, 60 through the air inlet 51i, and thus into the combustion air. Can be effectively suppressed.

  The engine cover 15 is provided with a raised portion 15p protruding upward in the air intake space 40 between the outside air inlet 42 and the upstream end 51i1 in the front-rear direction and at the same position as the upstream end 51i1 in the left-right direction. As a result, the ridge 15p prevents water that has entered from the rear from the rear through the outside air inlet 42 from reaching the upstream end port 51i1, so that the water is prevented from entering the intake silencer 50.

  The upstream end port 51i1 and the downstream end port 51o2 are arranged to be separated from each other in the front-rear direction and distributed in the front-rear direction with respect to the rotation center line Le of the crankshaft 8. The front-rear range includes the upstream end port 51i1 and the downstream end in the front-rear direction. By extending in the front-rear direction beyond the arrangement range Y of the end port 51o2, the outside air inlet 42 is arranged in the front-rear direction with respect to the rotation center line Le, and the arrangement range Y of the upstream end port 51i1 and the downstream end port 51o2 Since the length of the outside air inlet 42 in the front-rear direction can be increased, the opening width W of the outside air inlet 42 can be reduced, and entry of water and foreign matter can be suppressed.

An internal combustion engine E including an intake device 30 that guides combustion air to a combustion chamber 22 formed in the engine body, an engine cover 15 that forms an engine room R in which the internal combustion engine E is accommodated, and an engine cover 15 are covered from above. In the outboard motor S including the top cover 27 and the intermediate cover 28, the engine cover 15, the top cover 27, and the intermediate cover 28 form an air intake space 40 having an outside air intake 42 for taking outside air as combustion air. The outboard motor S is disposed outside the engine room R, and includes an upstream side intake silencer 50 that guides combustion air in the air intake space 40 to an intake device 30 disposed in the engine room R. The device 30 includes a downstream side intake silencer 60 to which combustion air from the intake silencer 50 is guided, and a throttle valve device 31 to which combustion air from the intake silencer 60 is guided. Are an air introduction port 51i that opens into the air intake space 40 and into which combustion air in the air intake space 40 flows, and an air outlet port through which combustion air in the intake silencer 50 flows out to the intake silencer 60 The intake silencer 60 is provided with an intake inlet 61i connected to the air outlet 51o, and an intake outlet 61o through which combustion air in the intake silencer 60 flows into the throttle passage 33 of the throttle valve device 31. The air inlet 51i is disposed in front of the air outlet 51o, and in the front-rear direction, the intake outlet 61o is opposite to the air inlet 51i with respect to the air outlet 51o and the inlet 61i. Placed in.
With this structure, the intake device 30 disposed in the engine room R includes the intake silencer 60, and the intake silencer 50 that guides combustion air to the intake silencer 60 is provided outside the engine room R. Intake pulsation from the device 30 is attenuated by the upstream silencer 50, and intake noise is reduced.
In addition, in the intake silencer 50, the air introduction port 51i that opens to the air intake space 40 formed outside the engine room R is disposed in front of the air outlet port 51o, so that the outside air intake 42 is provided with air intake. When opening rearward at the rear end of the inlet space 40, the distance in the front-rear direction from the outside air inlet 42 to the air inlet 51i can be increased, so that water that has entered the air inlet space 40 is sucked into the intake silencer. Entering 50 is suppressed. As a result, water can be effectively prevented from entering the intake silencer 50 through the air inlet 51i, and thus into the combustion air.
Further, in the front-rear direction, the intake outlet 61o is arranged on the opposite side of the air inlet 51i with respect to the air outlet 51o and the inlet inlet 61i, so that the air outlet 51o and the inlet 61i are changed from the air inlet 51i. Then, the flow of combustion air reaching the intake outlet 61o through the engine is smoothed in the front-rear direction and the intake resistance is reduced, so that the volumetric efficiency is improved and the engine output performance is improved.

In plan view, the air outlet 51o, the intake inlet 61i, and the intake outlet 61o are arranged so as to intersect with one straight line La that intersects the air inlet 51i and the throttle passage 33. 51i, the air outlet 51o, the intake inlet 61i, the intake outlet 61o, and the throttle passage 33 are arranged in a straight line. Since the flow of air, that is, the flow of combustion air in both intake silencers 50 and 60, is suppressed from being bent in the left-right direction and smoothed in the left-right direction, intake resistance is reduced and volume efficiency is improved. improves.
The throttle passage 33 extends in the front-rear direction or along the straight line La in plan view, thereby reducing the intake resistance in the passage from the intake silencers 50 and 60 to the throttle valve device 31 and improving the volume efficiency. To do.

  The intake silencer 50 is separated from the engine cover 15 so that an air intake space 40 is formed between the engine cover 15 and the intake silencer 50. As a result, the intake air pulsation transmitted from the intake device 30 to the air intake space 40 is suppressed, and noise caused by the vibration of the engine cover 15 that forms the air intake space 40 is reduced. .

  The ventilation device that forms the outlet passage 81 that guides the air in the engine compartment R to the outside of the engine compartment R includes a case 92 disposed in the engine compartment R, and a discharge passage that is formed by the case 92 and that communicates with the outlet passage 81. 91, and a fan 93 that pumps the air in the engine room R to the outlet passage 81. The discharge passage 91 has an inlet 91i that is disposed in the upper end space Ra of the engine room R and opens upward. In order to discharge the air in the engine room R of the outboard motor S to the outside of the engine room R through the outlet passage 81 by the fan 93, the inlet 91i of the discharge passage 91 in which the fan 93 is disposed Since it is arranged in the upper end space Ra of the room R and opens upward, the upper end space Ra of the engine room R where high-temperature air after cooling the engine gathers is increased. Warm air can be efficiently sucked by the fan 93 and efficiently discharged outside the engine room R and thus outside the outboard motor SS. As a result, the ventilation efficiency in the engine room R is improved, and the cooling effect of the internal combustion engine EE and the temperature rise suppression effect in the engine room R by the ventilation air are improved.

  A generator G is disposed in the engine room R, and a wind guide part D that forms a guide passage 129 for guiding the air after cooling the generator G to the inlet 91i is disposed in the engine room R. As a result, the exhaust air, which is high-temperature air after the generator G is cooled in the engine room R, flows into the inlet of the exhaust passage 91 where the fan 93 is disposed by the guide passage 129 formed by the air guide component D. 91i is guided so that the exhausted air is prevented from diffusing in the engine room R, and the exhausted air can be efficiently sucked into the fan 93. The temperature rise suppression effect is improved.

  A discharge passage 91 disposed in the engine room R and a lead-out passage 81 disposed outside the engine room R are disposed in the engine room R by being disposed at the same position as the generator G in the front-rear direction. The exhaust passage 91 and the outlet passage 81 arranged outside the engine room R can be concentrated in the vicinity of the generator G in the front-rear direction, so the arrangement range of the exhaust passage 91 arranged in the engine room R Y can be reduced, and the engine cover 15 can be downsized, and the outboard motor S can be downsized.

  The ventilator that forms the outlet passage 81 that guides the air in the engine room R to the outside of the engine room R is disposed in the discharge passage 91 that is continuous with the outlet passage 81 and is a fan that pumps the air in the engine room R to the outlet passage 81. 93 and around the generator G arranged in the engine room R, there is an air guide component D for guiding the exhaust air, which is the air after cooling the generator G, to the inlet 91i of the discharge passage 91. By disposing the fan 93 for discharging the air in the engine room R of the outboard motor S to the outside of the engine room R through the outlet passage 81, the fan 93 is arranged in the outlet passage 91 connected upstream of the outlet passage 81. The wind guide component D that guides the exhaust air, which is high-temperature air after cooling the generator G arranged in the room R, to the inlet 91i of the discharge passage 91 in which the fan 93 is arranged is the generator G. Since it is arranged around the It is suppressed from diffusing in the engine room R, and the exhaust air can be efficiently sucked into the fan 93, and the cooling effect of the generator G by the ventilation air and the temperature increase suppressing effect in the engine room R are improved. To do.

  The wind guide component D forms a wind guide cover 111 that surrounds the housing 102 of the generator G, and a guide passage 129 that guides the exhaust air from the wind guide space 113 formed by the wind guide cover 111 and the housing to the inlet 91i. The guide passage 129 is formed by the cooperation of the guide wall 121 and the engine cover 1515, and flows out to the wind guide space 113 formed by the wind guide cover 111 of the wind guide component D. In order to guide the exhaust air to the fan 93, the guide passage 129 for guiding the exhausted air to the inlet 91i of the exhaust passage 91 is formed by the cooperation of the guide wall 121 of the wind guide component D and the engine cover 15. Since the guide passage 129 is formed using the engine cover 15, the air guide part D having the guide wall 121 forming the guide passage 129 can be reduced in size and weight, and the engine cover 15 Downsizing of the outboard motor S It becomes ability.

  The inflow port 91i is disposed in the upper end space Ra of the engine room R and opens upward, so that the inflow port 91i is disposed in the upper end space Ra of the engine room R and opens upward. Thus, the high-temperature air in the upper end space Ra where the high-temperature air after cooling the internal combustion engine EE is collected is efficiently sucked by the fan 93 and efficiently discharged to the outside of the engine room R and eventually to the outside of the outboard motor S. Therefore, the ventilation efficiency in the engine room R is improved, and the cooling effect of the internal combustion engine E and the temperature rise suppression effect in the engine room R by the ventilation air are improved.

  The air guide space 113 is provided in the air guide cover 111, and has an air exhaust port 114 through which the exhaust air in the air guide space 113 flows into the engine room R in a direction approaching the air inlet 91i. The guide wall 121 is disposed above the air exhaust port 114, and the guide wall 121 has an inclined wall 122 that deflects the air exhaust discharged from the air exhaust port 114 obliquely upward, so that the air exhaust from the generator G is guided. The air flows out in the direction approaching the inlet 91i of the discharge passage 91 in which the fan 93 is arranged from the outlet 114 of the wind cover 111 and is deflected toward the inlet 91i located above the outlet 114 by the inclined wall 122. Therefore, by the exhaust air flowing through the guide passage 129 formed by the cooperation of the engine cover 15 and the guide wall 121, the air heated and raised in the engine room R is attracted in the direction toward the inflow port 91i, It goes to the inflow port 91i with the wind exhaust. As a result, exhaust air and air in the engine room R can be efficiently sucked into the fan 93, and the cooling effect of the generator G by the ventilation air and the temperature rise suppression effect in the engine room R are improved.

  The fan 93 is provided in the crankshaft 8 of the engine, and the discharge port 81o of the lead-out passage 81 that opens to the outside air is disposed in the discharge passage 91 by being disposed in front of the rotation center line Le of the crankshaft 8. The discharge port 81o that discharges the air that has been discharged from the engine room R by the fan 93 and is guided to the air guide passage 81 to the outside air is disposed in front of the rotation center line Le. It is prevented from being blocked by waves from behind, and the air in the engine room R can be efficiently discharged to the outside of the outboard motor S.

  The ventilation device includes a discharge passage component 90 including a fan 93 and a case 92 that forms a discharge passage 91, and the wind guide component D is integrated with the discharge passage component 90, whereby the fan 93, A discharge passage component 90 including a case 92 that forms the discharge passage 91 and a wind guide component D that guides the exhaust air from the generator G to the inflow port 91i of the discharge passage 91 are integrated. Since the machine G, the fan 93 and the inlet 91i can be arranged close to each other, it is possible to efficiently prevent the exhaust air from diffusing in the engine room R, and to guide the exhaust air to the fan 93. The wind component D and the discharge passage component 90 can be reduced in size and weight.

Hereinafter, the configuration in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
A part of the intake silencer 50 is configured by the top cover 27, but may be configured by a member separate from the top cover 27.
The outside air inlet 42 may be formed on at least one side with respect to the upstream end ports 51i1 and 61i1 in the left-right direction. Further, the rear end portion of the air intake space 40 may be closed without forming the outside air inlet 42, and in this case, both sides or one side of the inlet and the outlet in the left-right direction. Thus, combustion air is taken in from the outside air inlet 42 extending in the front-rear direction.
The internal combustion engine may be a V-type internal combustion engine other than six cylinders, a multi-cylinder internal combustion engine in which a plurality of cylinders are arranged in series, or a single-cylinder internal combustion engine.

It is a principal part right view of the outboard motor to which this invention was applied. FIG. 4 is a cross-sectional view mainly taken along line IIa-IIa in FIG. 3, and a part thereof is taken along a line IIb along the cylinder axis. FIG. 2 is a top plan view of a main part when a top cover and an intermediate cover of the outboard motor of FIG. 1 are removed. FIG. 2 is a plan view of the main part of the intermediate cover of the outboard motor of FIG. 1, and the top cover is indicated by a two-dot chain line. FIG. 2 is a plan view of an engine cover, an intermediate cover, and a top cover of the outboard motor of FIG. 1. FIG. 2 is a perspective view of a main part of the outboard motor of FIG. 1. FIG. 3 is an enlarged view of a main part in the vicinity of a grip part in FIG. 2. It is a principal part enlarged view of the intake silencer vicinity of FIG. FIG. 3 is an enlarged view of a main part in the vicinity of a discharge passage part in FIG. 2, and a part of a wind guide part is shown in appearance. It is the figure which divided the principal part enlarged view of the seal member vicinity of an inlet duct of FIG. 2, (a) on the left side shows the state before a channel | path formation part and an inlet duct are connected, and ( b) shows a state in which the passage forming portion and the inlet duct are connected. FIG. 2 is a schematic top plan view of the outboard motor of FIG. 1. It is principal part sectional drawing in the XII-line of FIG. FIG. 2 is a top plan view of a main part of a discharge passage part and a wind guide part of the outboard motor of FIG. 1. FIG. 2 is a perspective view from above of a discharge passage component and a wind guide component of the outboard motor of FIG. 1. It is a perspective view from the downward direction of the discharge channel | path component of FIG. 14, and a wind guide component. It is principal part sectional drawing in the XVI-XVI line | wire of FIG.

Explanation of symbols

2 ... cylinder head, 8 ... crankshaft, 15 ... engine cover, 15e ... coupling part, 15m ... passage forming part, 24, 25 ... transmission mechanism, 27 ... top cover, 27f ... coupling part, 28 ... intermediate cover, 28e, 28f ... coupling part, 40 ... air intake space, 42 ... outside air intake, 50 ... intake silencer, 51 ... air intake passage, 51i ... air inlet, 51o ... air outlet, 55 ... inlet duct, 60 ... intake Silencer, 61 ... upstream intake passage, 61i ... intake inlet, 61o ... intake outlet, 67 ... top wall, 70 ... introduction part, 71 ... introduction passage, 71i ... inlet, 71o ... outlet, 80 ... outlet part, 81 ... Exit passage, 81i ... Inlet, 81o ... Discharge port, 90 ... Discharge passage part, 91 ... Discharge passage, 91o ... Ventilation outlet, 93 ... Fan, 94 ... Deflection wall, 97 ... Exit duct, 103 ... Inlet, 104 ... Outlet, 111 ... Air guide cover, 114 ... Exhaust port, 121 ... Guide wall, 122 ... Inclined wall, 123 ... Deflection wall, 129 ... Guide passage, 130 ... Parts, 140, 150, 149, 159 ... sealing member,
S ... Outboard motor, P ... Power unit, E ... Internal combustion engine, R ... Engine room, J1-J4 ... Butt face, Ri ... Ventilation inlet, G ... Generator, A ... Projection wall, D ... Wind guide component.

Claims (3)

In an outboard motor comprising an internal combustion engine (E) in which a combustion chamber (22) is formed,
An upper intake silencer (50) into which combustion air flows, and a lower intake silencer (60) for guiding combustion air from the upper intake silencer (50) to the combustion chamber (22) are vertically moved Placed one on top of the other
The upper intake silencer (50) disposed above the lower intake silencer (60) has an air inlet (51i), an upper expansion chamber (51a), and an air outlet (51o). Provided,
The lower intake silencer (60) is provided with an intake inlet (61i) connected to the air outlet (51o), a lower expansion chamber (61a), and an intake outlet (61o),
The top wall (67) of the lower expansion chamber (61a) overlaps the lower high wall portion (67a) with the bottom wall (53) of the upper expansion chamber (51a) in plan view and the lower high wall A step-shaped wall having a lower low wall portion (67b) located below the portion (67a),
The outboard motor, wherein the intake inlet (61i) is disposed in the lower low wall portion (67b). The bottom wall (53) of the upper expansion chamber (51a) includes an upper high wall portion (53a) that overlaps the lower intake silencer (60) in plan view, and the lower intake silencer (60) in plan view. A step-shaped wall having an upper low wall portion (53b) positioned below the upper high wall portion (53a) without overlapping with
The outboard motor according to claim 1, wherein the air outlet (51o) is disposed in the upper high wall (53a). The upper intake silencer (50) and the lower intake silencer (60) are arranged with an engine cover (15) forming an engine room (R) in which the internal combustion engine (E) is accommodated,
The upper intake silencer (50) is outside the engine room (R), and is formed by an air cover formed by the engine cover (15) and an exterior cover (27, 28) covering the engine cover from above. Placed in space (40),
The outboard motor according to any one of claims 1 to 2 , wherein the lower intake silencer (60) is disposed in the engine room (R).

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