JP2007008416A - Outside air intake structure of outboard motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily attach/detach an engine cover while avoiding an increase in the weight thereof and inward projection thereof, and to suppress deposition of water in the taken-in outside air around an engine. <P>SOLUTION: Right and left air intake ducts 20, 40 are screw-fixed to a head cover 33 and a surge tank 38. In an engine cover assembly 60, a top cover 12, a louver 13, right and left air intake guides 14, 15 or the like are assembled to an upper cover 10. In the attached state, a flow passage connected from the air intake guides 14, 15 to the air intake ducts 20, 40 is formed. Outside air is discharged to a lower part in the upper cover 10 from the louver 13 through the air intake guides 14, 15 and the air intake ducts 20, 40, and flows upwardly in the front of the surge tank 38, and flows into a throttle body 29. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an outside air intake structure for an outboard motor that introduces outside air from an outside air inlet provided at an upper rear portion of an engine cover.

  Conventionally, an outboard motor having an outside air intake structure in which an outside air inlet is provided at an upper rear portion of an engine cover is known. In this type of outboard motor, it is necessary to prevent water from entering the engine because mist-like seawater or the like easily enters the engine cover from the outside air intake. Further, if water adheres to parts around the engine, the parts may be corroded, so it is necessary to prevent water from adhering to the parts around the engine.

  Therefore, in the outside air intake structures of Patent Documents 1 and 2 below, the engine cover is provided with a duct from the outside air inlet to the lower part in the engine cover. However, since the engine cover is particularly heavy in a large outboard motor due to the duct provided in the engine cover, it is difficult to attach and detach the engine cover. In addition, when covering the engine cover, in general, it is often not from directly above, but from an oblique direction. Therefore, if a projecting portion due to a duct exists on the inner side of the engine cover, it interferes with the engine and interferes with the engine cover. Can not be worn well. Therefore, there has been a problem that the engine cover is not easily attached and detached.

On the other hand, in the outside air intake structure of Patent Document 3 below, a duct communicating with the outside air inlet is attached to the engine side, and the lower end of the duct extends downward from the mating surface of the top cowl and the bottom cowl.
Japanese Patent Laid-Open No. 4-166396 Japanese Examined Patent Publication No. 7-77878 Japanese Patent Laid-Open No. 7-91276

  However, the outside air intake structure of Patent Document 3 has a configuration in which the intake port of the duct is located behind the engine, so that the outside air taken in from the outside air inlet is easily introduced directly into the duct. Therefore, there is not much water that enters the duct itself, and the effect of preventing water from adhering around the engine is not sufficient.

  By the way, in the outside air intake structures of Patent Documents 1 and 3, since the outside air introduced into the engine cover is warmed by the engine before reaching the intake device, there is a problem that the engine output decreases. In the outside air intake structure of Patent Document 2 described above, the effect of preventing the warming of outside air is not sufficient, and there is room for improvement in terms of preventing a decrease in engine output.

  Furthermore, in the outside air intake structure of Patent Document 3, since the duct projects to the rear of the engine, the engine cover is increased in size by the amount of the duct. Therefore, there is room for improvement in providing a duct so that the engine cover does not become large.

  The present invention has been made in order to solve the above-described problems of the prior art, and an object thereof is to avoid the increase in weight of the engine cover and the inward protrusion to facilitate attachment / detachment, and to take in the water in the outside air taken in. An object of the present invention is to provide an outside air intake structure for an outboard motor that can suppress the adhesion of the engine around the engine.

  In order to achieve the above object, the outside air intake structure for an outboard motor according to claim 1 of the present invention is an outboard motor having an outside air inlet (13) provided at the upper rear portion of an engine cover (10) covering the engine. In the outside air intake structure, the air intake ducts (20, 40) fixedly disposed on the engine side and the air intake duct are connected to the outside air intake when the engine cover is mounted. Air intake guides (14, 15) for guiding outside air taken from the air intake duct to the air intake duct, and the outside air taken in from the outside air intake port passes through the air intake guide and the air intake duct into the engine cover. It is structured to be guided to the lower part of the head.

  According to the first aspect of the present invention, it is possible to avoid the increase in the weight of the engine cover and the inward protrusion to facilitate attachment and detachment, and it is possible to suppress the water in the taken outside air from adhering around the engine. .

  According to the second aspect, the air intake duct can be substantially accommodated in the outline of the engine in a plan view, and the enlargement of the engine cover can be suppressed.

  According to the third aspect of the present invention, the water in the outside air that has been taken in can hardly enter the air intake guide, and the adhesion of water around the engine can be more effectively suppressed.

  According to the fourth aspect of the present invention, it is possible to suppress the decrease in engine output due to the increase in intake air temperature by making it difficult for the outside air taken in to be warmed in the engine cover.

  According to the fifth aspect, it is possible to ensure the flow path area in the air intake duct by effectively utilizing the empty space.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an upper half portion of an outboard motor having an outside air intake structure according to an embodiment of the present invention. FIG. 2 is a horizontal sectional view of the outboard motor. The outboard motor 1 includes an engine 2 as shown in FIG. The engine 2 has a V-shaped configuration in which a crankshaft 32 is disposed substantially vertically (vertically) and a left and right cylinder block 50 is installed in a V shape in plan view to open rearward. This is a water-cooled 4-cycle V-type 6-cylinder engine in which a cylinder bank (V bank) is formed.

  As shown in FIG. 1, the periphery of the engine 2 is covered with an upper cover 10 and a lower cover 11. A top cover (tilt-up handle) 12 is mounted on the upper cover 10, and a louver 13 serving as an outside air inlet is attached between the rear portion of the upper cover 10 and the rear portion of the top cover 12.

  As shown in FIG. 2, the crankcase 31 is disposed at the foremost part (the bow side) of the engine 2, and the cylinder block 50 is disposed behind the crankcase 31. A crankshaft 32 is pivotally supported on the mating surface of the crankcase 31 and the cylinder block 50. The upper end of the crankshaft 32 protrudes above the engine 2 and a power generating magnet device (not shown) is provided at the protruding portion. Hereinafter, the configuration of the cylinder bank on one side (right side) will be mainly described, but the left and right cylinder banks are basically configured similarly.

  The cylinder block 50 has a left bank portion 50L and a right bank portion 50R. A pair of left and right cylinder heads 80 are provided corresponding to the left and right cylinder banks, and the cylinder heads 80L and 80R correspond to the left and right bank portions 50L and 50R, respectively. Three cylinders 51 are formed in each of the left and right bank portions 50L and 50R. On the other hand, each cylinder head 80 is formed with a combustion chamber 52 aligned with each cylinder 51, and an intake port 89 and an exhaust port 90 communicating with the combustion chamber 52. Head covers 33 (33L, 33R) are respectively mounted on the cylinder head 80, and intake and exhaust camshafts (not shown) are rotatably supported in cam chambers defined therebetween. .

  The intake port 89 has an inlet that opens to the inside of the V shape that each cylinder bank exhibits, and a communication portion to the combustion chamber 52 is opened and closed by the intake valve 55. Further, the exhaust port 90 is formed in a V-shaped outer portion (outer portion of the cylinder head 80) exhibited by each cylinder bank, and the communication portion to the combustion chamber 52 is opened and closed by the exhaust valve 54. The reciprocating motion of the piston 53 slidably inserted into each cylinder 51 is converted into the rotational motion of the crankshaft 32 via the connecting rod 34.

  A fuel filter 35 is disposed on the left side of the crankcase 31, and a starter motor 36 is disposed on the right side.

  FIG. 3 is an exploded perspective view of the engine cover assembly including the upper cover 10 and related parts. FIG. 4 is an external view of the upper half of the outboard motor 1 with the engine cover assembly 60 removed. FIG. 5 is an external view in which the louver 13 and the left and right air intake guides are added to FIG.

  As shown in FIG. 2, a surge tank 38 is provided behind the center of the engine 2 via an intake manifold 37 connected to the intake port 89. As shown in FIG. 4, a throttle body 29 is connected to the upper portion of the surge tank 38. The throttle body 29 opens into a silencer 19 disposed at the upper rear part of the engine 2, and takes in outside air introduced into the silencer 19 from the opening, and the surge tank 38 draws the outside air from the throttle body 29. take in. These intake manifold 37, surge tank 38, throttle body 29, silencer 19 and the like constitute an intake device.

  As shown in FIG. 3, the engine cover assembly 60 is constructed by assembling the upper cover 10 with the left and right air intake guides 14 and 15 in addition to the top cover 12 and the louver 13. There are other parts that can be attached to the upper cover 10, but their illustration and description are omitted.

  A cover portion 18 that covers the silencer 19 is integrally formed at the rear center of the upper surface 10 a of the upper cover 10. In the rear part of the upper surface 10 a of the upper cover 10, substantially triangular holes 16 and 17 are formed on the left and right sides of the cover part 18. At the front portions of the air intake guides 14 and 15, quadrangular upper openings 14 a and 15 a that open upward are provided. The upper opening 14a is slightly to the right of the front of the left air intake guide 14 (near the center of the upper cover 10), and the upper opening 15a is slightly to the left of the front of the right air intake guide 15 (near the center of the upper cover 10). ), Respectively. In addition, the air intake guides 14 and 15 are formed with lower openings 14b and 15b that are long in the front-rear direction and open downward with the lower edges 14c and 15c as outer edges. The insides of the air intake guides 14 and 15 are hollow.

  The air intake guides 14 and 15 are disposed at positions so as to cover the front hole portions 10ab and 10ac and the holes 16 and 17, which are front portions of the holes 16 and 17, respectively, of the upper surface 10a of the upper cover 10. It is fixed to the upper surface 10a by screws (not shown). At that time, the contact portion between the upper surface 10a of the upper cover 10 and the lower edge portions 14c and 15c is sealed with a liquid gasket or the like. Thereby, since the hole front portions 10ab and 10ac partition the front half of the lower openings 14b and 15b, the passage from the upper openings 14a and 15a to the holes 16 and 17 is in a communicating state.

  The top cover 12 is fixed to the upper part of the upper cover 10 with screws. The louver 13 is fixed to the rear portion of the top cover 12 and the rear portion of the upper cover 10 with screws.

  As shown in FIGS. 2 and 4, left and right air intake ducts 20 and 40 are provided on the left and right sides of the rear of the engine 2. The air intake ducts 20 and 40 are disposed immediately behind the head covers 33L and 33R in the space between the engine 2 and the intake manifold 37, respectively. Accordingly, the air intake ducts 20 and 40 are substantially within the outline of the engine 2 in a plan view (FIG. 2).

  The air intake ducts 20 and 40 are cylindrical members penetrating in the vertical direction up to the lower end position of the engine 2, and their cross sections are substantially triangular shapes corresponding to the holes 16 and 17 of the upper cover 10. The outer shape of the air intake ducts 20 and 40 is slightly smaller than the holes 16 and 17 of the upper cover 10. The upper ends 20a and 40a of the air intake ducts 20 and 40 serve as outside air inlets, and the lower ends of the air intake ducts 20 and 40 serve as exhaust ports. Seal members 26 and 46 are attached to the upper ends 20a and 40a.

  As shown in FIG. 4, stays 23 and 24 are integrally formed at the rear portion of the left air intake duct 20. The left air intake duct 20 is screwed and fixed with screws 21 and 22 at two upper portions of the head cover 33L, and stays 23 and 24 are screwed and fixed to the left side of the surge tank 38 with screws 27 and 28. The engine 2 is fixed.

  As shown in FIG. 2, a partition plate 25 is integrally formed to extend from the front left side of the left air intake duct 20. The partition plate 25 extends from a position slightly lower than the upper end of the left air intake duct 20 to a lower end position, and extends rearward to a position substantially covering the left side portion of the head cover 33L. The front end of the partition plate 25 is close to the upper cover 10, and the partition plate 25 allows the space on the left side of the engine 2 in the upper cover 10 to be the main heat source from the engine body (from the crankcase 31 to the vicinity of the head cover 33L). And the intake device side (the side where the intake manifold 37 and the surge tank 38 are provided).

  Further, the right air intake duct 40 is also configured symmetrically with the left air intake duct 20. Then, while being screwed and fixed with screws 41 and 42 at two upper portions of the head cover 33R (see FIG. 4), it is screwed and fixed to the right side of the surge tank 38 via a stay (not shown), thereby 2 is fixed.

  Further, a partition plate 45 (see FIG. 2) is integrally extended from the front right side portion of the right air intake duct 40. The partition plate 45 is configured to be bilaterally symmetric with respect to the partition plate 25. Therefore, the partition plate 45 allows the space on the right side of the engine 2 in the upper cover 10 to be the engine body (part from the crankcase 31 to the vicinity of the head cover 33R). And the intake device side.

  Further, an upper partition plate 57 having a “H” shape in plan view is provided on the upper rear portion of the flywheel magneto cover 56 that covers the magneto device (not shown) (see FIG. 4). The upper partition plate 57 divides the space above the engine 2 in the upper cover 10 into an engine body side and an intake device side. That is, the upper partition plate 57 and the partition plates 25 and 45 cooperate to partition the space in the upper cover 10 in the front-rear direction, that is, the engine body side and the intake device side. In addition, the exhaust port, which is the lower end of the air intake ducts 20 and 40, is open to the partitioned space on the intake device side.

  When the assembled engine cover assembly 60 (see FIG. 3) is put on the outboard motor 1 in the state shown in FIG. 4 from above, the louver 13 and the air intake guides 14 and 15 in the engine cover assembly 60 are shown in FIG. Located in such a position. In FIG. 5, the top cover 12 and the upper cover 10 are not shown. The upper openings 14a and 15a of the air intake guides 14 and 15 are located at substantially the center of the engine 2 in plan view. That is, the upper openings 14a and 15a are arranged at positions that are separated from any part of the louver 13 that is curved so as to wrap around left and right. In addition, interference between the upper openings 14a and 15a and the magneto device (not shown) is also avoided.

  When the engine cover assembly 60 is mounted, the upper ends 20a, 40a (see FIG. 4) of the air intake ducts 20, 40 are substantially flush with the hole front portions 10ab, 10ac (see FIG. 3) of the upper surface 10a of the upper cover 10. It becomes. Accordingly, portions of the lower edge portions 14c and 15c of the air intake guides 14 and 15 corresponding to the upper ends 20a and 40a come into contact with the upper ends 20a and 40a through the holes 16 and 17 and the seal members 26 and 46, respectively. Thereby, the upper intake openings 14a and 15a of the air intake guides 14 and 15 through the holes 16 and 17 to the lower ends (exhaust ports) of the air intake ducts 20 and 40 are in communication with each other. The seal members 26 and 46 form a passage for outside air so as not to leak on the way. As described above, since the passage of the outside air is automatically formed only by covering the engine cover assembly 60 from above, there is no hindrance to the attachment / detachment operation of the engine cover assembly 60.

  FIG. 6 is a schematic view corresponding to a side view showing an introduction path of outside air taken into the engine 2. In the figure, the flow of outside air to be introduced is indicated by an arrow A. In a state where the engine cover assembly 60 is attached, outside air is first taken into the upper cover 10 from the louver 13. An opening 19a is formed in the front part of the silencer 19 (see FIGS. 4, 5, and 6), but above the opening 19a of the silencer 19 is the front part of the cover part 18 (see FIG. 3). Since it is covered with 18a, the outside air does not flow directly into the opening 19a.

  Outside air that has entered from the louver 13 enters the air intake guides 14 and 15 from the upper openings 14 a and 15 a of the air intake guides 14 and 15. At that time, since the upper openings 14a and 15a are separated from the louver 13, water such as mist contained in the outside air easily drops in the middle, and the water entering the air intake guides 14 and 15 can be reduced. it can.

  The outside air that has entered the air intake guides 14 and 15 is introduced into the air intake ducts 20 and 40 from the upper ends 20 a and 40 a of the air intake ducts 20 and 40. Then, the air intake ducts 20 and 40 are discharged into the upper cover 10 through the exhaust ports at the lower ends. Since the lower ends of the air intake ducts 20 and 40 are located in the vicinity of the lower end of the engine 2, it is difficult for water in the outside air to adhere to parts around the engine 2.

  The outside air discharged from the lower ends of the air intake ducts 20 and 40 flows backward in the upper cover 10, rises in front of the surge tank 38, and flows into the throttle body 29. Thereafter, the fuel is supplied to the combustion chamber 52 through the surge tank 38, the intake manifold 37, and the intake port 89 (see FIG. 2). The air intake ducts 20 and 40 are in a relatively cool space on the intake device side partitioned by the partition plates 25 and 45, and the front space of the surge tank 38 is also a space on the intake device side. It is difficult to warm up on the way and is supplied to the engine 2 in a cold state.

  According to the present embodiment, when the engine cover assembly 60 is attached, the air intake ducts 20 and 40 are connected to the air intake guides 14 and 15, and the outside air taken in from the louver 13 is supplied to the engine 2. Guided downward. Moreover, since the upper openings 14a and 15a of the air intake guides 14 and 15 are located at the approximate center of the engine 2 in plan view and are separated from the louver 13, the water in the outside air taken in is taken up by the air intake guide 14. , 15 is difficult to enter. Therefore, it is possible to effectively prevent the water in the outside air from adhering to the parts around the engine 2 and corroding the parts.

  In addition, since the air intake ducts 20 and 40 are fixed not to the engine cover assembly 60 side but to the engine 2 side, the weight of the engine cover assembly 60 does not increase, and the air intake duct 20 is provided inside the upper cover 10. , 40 does not exist so that the engine cover assembly 60 can be easily mounted and removed. In particular, when the outboard motor 1 is large, the upper cover 10 is considerably heavy, but the weight reduction greatly contributes to the easy attachment / detachment operation. Further, in general, the upper cover 10 is often covered in an oblique direction rather than vertically, so that there is no projecting object on the inside, so that interference with the engine 2 is avoided, and attachment / detachment operation is facilitated. Contribute to.

  Further, the partition plate 25, 45 provided integrally with the air intake ducts 20, 40 divides the space in the upper cover 10 into the engine main body side and the intake device side, and the air intake ducts 20, 40 and their exhaust ports are separated. Is located in the space on the intake device side. Further, the throttle body 29 is located at the upper rear part of the engine 2. Moreover, the upper partition plate 57 also partitions the engine body side and the intake device side more clearly. With these configurations, since the taken-in outside air passes through a path that is not easily warmed by the heat of the engine 2, it is possible to suppress a decrease in engine output due to an increase in intake air temperature, mainly a decrease in output during full throttle operation.

  In addition, the space behind the left and right cylinder heads 80L and 80R of the engine 2 that is a V-type engine is likely to have an empty space, but the left and right air intake ducts 20 and 40 are disposed in this space (see FIG. 2). In addition, the air intake ducts 20 and 40 can be secured without difficulty, and the space in the air intake ducts 20 and 40 can be secured without difficulty by effectively utilizing the vacant space. In addition, since the air intake ducts 20 and 40 are substantially within the outline of the engine 2 in plan view, the upper cover 10 can be prevented from being enlarged.

  In the present embodiment, the air intake guides 14 and 15 are fixed to the upper cover 10 and the top cover 12, but the present invention is not limited to this. For example, the air intake guides 14 and 15 are integrated with the upper cover 10 by integral molding. You may comprise an upper air intake. In that case, if a plate-like member corresponding to the hole front portions 10ab, 10ac (see FIG. 3) of the upper surface 10a of the upper cover 10 is attached to the lower opening of the air intake guide, the configuration is the same as the above (FIG. 3). In addition, a passage of outside air from the air intake guide to the air intake ducts 20 and 40 can be formed.

  In the present embodiment, the V-type 6-cylinder engine is taken as an example. However, the present invention is not limited to this. As illustrated below, the configuration in which the air intake duct is fixed to the engine side is an in-line engine. It can also be applied to outboard motors.

  FIG. 7 is a schematic diagram of a horizontal cross section of an outboard motor including an inline engine according to a modification. As shown in the figure, in the upper cover 110, a crankcase 131, a cylinder block 150, a cylinder head 180, and a head cover 33 are disposed from the front to constitute an engine body. An intake manifold 137 is disposed on the right side of the engine body. The air intake duct 125 is disposed in a space between the engine body and the intake manifold 137, and is fixed to the cylinder block 150, for example.

  Even in such a configuration, the upper cover 110 can be easily attached / detached, the adhesion of water to the engine can be suppressed, and the flow passage area of the air intake duct 125 can be secured, and the air intake duct 125 can be disposed within the engine outline in a plan view. The upper cover 110 can be prevented from being enlarged.

It is a perspective view of the upper half part of an outboard motor which has an outside air intake structure outboard motor concerning one embodiment of the present invention. It is a horizontal sectional view of the outboard motor. It is a disassembled perspective view of the engine cover assembly which consists of an upper cover and a related component. FIG. 3 is an external view of the upper half of the outboard motor with the engine cover assembly removed. FIG. 5 is an external view in which a louver and left and right air intake guides are added to FIG. 4. It is a schematic diagram equivalent to the side view which shows the introduction path | route of the external air taken in into an engine. It is a schematic diagram of the horizontal cross section of an outboard motor provided with the serial type engine which concerns on a modification.

Explanation of symbols

1 Outboard motor 2 Engine 10 Upper cover (engine cover)
13 louvers (outside air intake)
14, 15 Air intake guides 14a, 15a Upper opening (suction port)
20, 40, 125 Air intake duct 25, 45 Partition plate 37 Intake manifold 38 Surge tank 80 Cylinder head

Claims (5)

In the outside air intake structure of an outboard motor in which an outside air inlet is provided at the upper rear part of the engine cover that covers the engine,
An air intake duct fixedly disposed on the engine side;
An air intake guide that is connected to the air intake duct when the engine cover is mounted and guides outside air taken in from the outside air intake to the air intake duct;
An outside air intake structure for an outboard motor, wherein outside air taken in from the outside air inlet is guided to a lower portion in the engine cover through the air intake guide and the air intake duct.   2. The outboard motor outside air intake structure according to claim 1, wherein the air intake duct is disposed in a space between the engine and an intake device.   The air intake guide has an inlet for introducing outside air taken in from the outside air inlet, and the inlet is provided at a position separated from the outside air inlet in a plan view. The outside air intake structure for an outboard motor according to claim 1 or 2.   The air intake duct is provided with a partition plate for partitioning a space in the engine cover into an engine body side and an intake device side, and an exhaust port of the air intake duct is provided on the partitioned intake device side. The outside air intake structure for an outboard motor according to any one of claims 1 to 3, wherein the structure is open to a space.   5. The engine according to claim 1, wherein the engine is a V-type engine having left and right cylinder heads, and one air intake duct is disposed behind each of the left and right cylinder heads. The outside air intake structure of the outboard motor according to item 1.

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