JPH11125162A - Fuel vapor separation device for outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhaust only fuel vapor by making respiration possible while stored fuel is being restrained from flowing out to an air vent pipe in an auxiliary fuel tank affected by the various kinds of inclination of an outboard motor, which is caused by the conditions of rolling, pitching, tilt-up, and steering at a tilt-up condition. SOLUTION: A first and a second air vent hole 1551 and 1552 opening their one side ends a1 and a2 in the upper space of the inside, and inflow air vent holes 157 relatively communicating the other side ends b1 and b2 . of these air vent holes with each other, are formed in the ceiling wall of an auxiliary fuel tank 892 , these one side ends a1 and a2 are relatively separated in the right and left directions of the auxiliary fuel tank 892 . so as to be disposed roughly at the center part in the longitudinal direction of the aforesaid tank, and concurrently, the other side ends a2 and a1 of the respective one side air vent holes 1551 and 1552 are disposed to the same side of the one side ends a2 and a1 of the other side end air vent holes 1552 and 1551 , and one air vent pipe is connected with the inflow air vent holes 157.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary fuel for receiving, in an engine room of an outboard motor, surplus fuel recirculating from a fuel injection valve side of an engine in the engine room and separating fuel vapor from stored fuel. A tank provided with a tank, an air vent pipe extending upward in communication with an upper space inside the auxiliary fuel tank, and fuel vapor generated in the auxiliary fuel tank being discharged through the air vent pipe; The present invention relates to a fuel vapor separation device in an outer unit.

[0002]

2. Description of the Related Art A fuel vapor separation device for such an outboard motor is already known, for example, as disclosed in Japanese Patent Application Laid-Open No. 4-295172.

[0003]

However, the outboard motor is
When mounted on the hull, rolling, pitching, tilting, steering in the tilted state, etc., necessitate a large inclination in various directions. It is necessary to suppress the outflow of the stored fuel to the air vent pipe, enable respiration, and discharge only fuel vapor.

[0004] It is an object of the present invention to provide a fuel vapor separation device for an outboard motor having a simple structure capable of satisfying such a demand.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an engine room of an outboard motor which receives excess fuel recirculated from a fuel injection valve side of an engine in the engine room, In a fuel vapor separation device for an outboard motor, an auxiliary fuel tank for separating fuel vapor from stored fuel is provided, and an air vent pipe extending upward in communication with an upper space inside the auxiliary fuel tank is connected to the auxiliary fuel tank.
The ceiling wall of the auxiliary fuel tank is formed with first and second air vent holes each having one end opening in the upper space, and a merged air vent hole communicating with the other ends of the first and second air vent holes. Said one end of the first and second air vent holes,
The auxiliary fuel tank is disposed at a substantially central portion in the front-rear direction of the auxiliary fuel tank while being spaced apart from each other in the left-right direction.
The first feature is that the other end of each one of the air vent holes is disposed on the same side in the left-right direction as one end of the other air vent hole, and the air vent pipe is connected to the merged air vent hole.

According to the first feature, even when the outboard motor is in various inclined postures, the open ends of the first and second air vent holes into the auxiliary fuel tank are simultaneously formed in the stored fuel liquid level. It does not sink down, and at least one of the opening ends can be exposed above the stored liquid level, and furthermore, it is possible to prevent fuel from entering the merged air vent hole. Therefore, the auxiliary fuel tank can breathe through the air vent hole, the merging air vent hole, and the air vent pipe exposed above the stored fuel liquid level, so that the fuel vapor generated in the auxiliary fuel tank is discharged from the auxiliary fuel tank. It can be discharged without letting it go. Moreover, since only one air vent pipe is required to be connected to the auxiliary fuel tank, it can contribute to simplification of the structure.

Further, in addition to the above-mentioned features, the present invention is characterized in that the first and second air vent holes are formed in a hook shape, and the first, second air vent holes and the merged air vent hole are arranged on the same horizontal plane. Features.

According to the second feature, the first and second air vent holes and the merged air vent hole are arranged on the same plane, thereby minimizing an increase in the thickness of the ceiling wall of the auxiliary fuel tank. These air vent holes can be formed in the ceiling wall.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 12 show an embodiment of the present invention. FIG. 1 is an overall side view of an outboard motor, and FIG.
2 is an enlarged cross-sectional view of FIG. 3, FIG.
5 is a sectional view taken along line 5-5 of FIG. 3, FIG. 6 is an enlarged sectional view of a main part of FIG. 3, FIG. 7 is a view taken along arrow 7 of FIG. 6, and FIG. 9, 10, 11 and 12 are arrows 9-9, 10-10, 11-11 and 12-of FIG. 7.
12, FIG. 13 is a cooling water circuit diagram, FIG. 14 is a view taken in the direction of arrow 14 in FIG. 3, and FIGS.
It is sectional drawing along line 5-15, line 16-16, and line 17-17.

Referring to FIG. 1, an outboard motor O as a power unit includes a mount case 2 as an engine support coupled to an upper portion of an extension case 1, and a water-cooled in-line four-cylinder 4 is provided on an upper surface of the mount case 2. The cycle engine E is supported with the crankshaft 15 placed vertically. An undercase 3 having an open upper surface is connected to the mount case 2. An engine cover 4 is detachably mounted on the upper portion of the undercase 3, and the mount case 2, the undercase 3, and the engine cover 4 are attached.
Thus, an engine room 36 for housing the engine E is defined.

An under cover 5 is mounted between the lower edge of the under case 3 and the edge near the upper end of the extension case 1 so as to cover the outside of the mount case 2.

The engine E includes a cylinder block 6, a crankcase 7, a cylinder head 8, a head cover 9, a lower belt cover 10, and an upper belt cover 11. The lower surfaces of the cylinder block 6 and the crankcase 7 Supported on top. A piston 13 is slidably fitted to each of the four cylinders 12 formed in the cylinder block 6, and each piston 13 is connected to a vertically disposed crankshaft 15 via a connecting rod 14.

A flywheel 1 is provided at the lower end of the crankshaft 15.
The drive shaft 17 connected with the extension case 6 extends downward inside the extension case 1, and the lower end thereof is connected to the gear case 18.
Is connected to a propeller shaft 21 having a propeller 20 at the rear end via a bevel gear mechanism 19 provided inside the. A lower end of a shift rod 22 is connected to a front portion of the bevel gear mechanism 19 so as to switch the rotation direction of the propeller shaft 21.

A swivel shaft 25 is fixed between an upper mount 23 provided on the mount case 2 and a lower mount 24 provided on the extension case 1, and the swivel case 2 rotatably supports the swivel shaft 25.
6 is supported by a stern bracket 27 attached to the stern S via a tilt shaft 28 so as to be vertically swingable.

An oil pan 2 is provided on the lower surface of the mount case 2.
9 and the exhaust pipe 30 are connected. The exhaust gas discharged from the exhaust pipe 30 to the internal space of the extension case 1 is
The propeller 20 passes through the hollow portion of the boss and is discharged into water.

As is apparent from FIG. 2, the engine E accommodated in the engine room 36 has two secondary balancer shafts 37 and 38 arranged in parallel with the crankshaft 15 and 1
And a plurality of camshafts 39. Secondary balancer shaft 37,3
8 is supported by the cylinder block 6 closer to the cylinder head 8 than the crankshaft 15, and the camshaft 39 is supported between the mating surfaces of the cylinder head 8 and the head cover 9.

At the upper end of the crankshaft 15 is fixed a pulley assembly 44 in which a camshaft drive pulley 40, a secondary balancer shaft drive pulley 41, a generator drive pulley 42 and a cooling fan 43 are integrated. The camshaft driven pulley 45 fixed to the upper end of the camshaft 39 and the camshaft driving pulley 40 are connected by an endless belt 46. Camshaft drive pulley 40
Is set to one half of the diameter of the camshaft driven pulley 45, so that the camshaft 39 rotates at half the speed of the crankshaft 15. Arm 4 pivoted by pin 47
A tension pulley 49 provided at one end of the endless belt 8 is pressed against the outer surface of the endless belt 46 by the resiliency of a spring 50, thereby applying a predetermined tension to the endless belt 46.

A pair of secondary balancer shaft driven pulleys 52, 5 fixed to an intermediate shaft 51 provided near one of the secondary balancer shafts 37 and the other secondary balancer shaft 38, respectively.
3 and the secondary balancer shaft driving pulley 41 are connected by an endless belt 54. A tension pulley 57 provided at one end of an arm 56 pivotally supported by a pin 55 is pressed against the outer surface of the endless belt 54 by the resilience of a spring 58, whereby a predetermined tension is applied to the endless belt 54. . Intermediate shaft 52 and one secondary balancer shaft 3
7 is connected by a pair of gears (not shown) having the same diameter, and the diameter of the secondary balancer shaft driving pulley 41 is 2
The diameter is set to twice the diameter of the secondary balancer shaft driven pulleys 52, 53, and therefore, a pair of secondary balancer shafts 37, 3
Reference numeral 8 rotates in opposite directions at twice the speed of the crankshaft 15.

On the upper surface of the crankcase 7, two bolts 5
The generator 62 is supported by the two bolts 61 on the bracket 60 fixed at 9. A generator driven pulley 64 fixed to a rotating shaft 63 of a generator 62 and the generator driving pulley 42
Are connected by an endless belt 65, and the crankshaft 15
Drives the generator 62. Thus, the generator 62
Provided separately from the engine E, it is possible to use a general-purpose generator 62 as compared with a case where the generator is incorporated in a flywheel provided on the crankshaft 15, which is advantageous in cost. Moreover, the capacity of the generator 62 can be easily increased.

Cam shaft 39, secondary balancer shafts 37, 38
And three belts 46, 54, 6 for driving the generator 62
5 is a lower belt cover 10 and an upper belt cover 11
Is housed in the belt chamber 68 defined by. Together with the lower belt cover 10 has an opening 10 ₁ surrounding the periphery of the generator 62 includes a plurality of slits 10 ₂ in the right side of the bottom wall of the crank shaft 15, through these openings 10 ₁ and the slits 10 ₂ Thus, air is introduced into the belt chamber 68.

2 to 4, a pair of left and right slit-shaped rear openings 4 ₁ are provided on the upper rear surface of the engine cover 4.
There is formed a guide plate 75 which front end in the front-rear direction intermediate portion of the engine room 36 extending from the lower edge of the rear opening 4 ₁ forward is fixed to the inner surface of the engine cover 4. At the time of fixing, the rear edge of the guide plate 75 is fixed to the inner surface of the engine cover 4 by the tap screw 73, and the boss 75 a at the intermediate portion is fixed by the tap screw 74. This guide plate 75, draining step portion 75 ₁ of the two-stage rising stepwise towards the rear opening 4 ₁ in the engine compartment 36, 75 ₂ are formed.

Thus, the rear opening 4₁Sky inhaled from
The air is sandwiched between the upper wall of the engine cover 4 and the guide plate 75.
Flows forward through the space, and the two-stage draining step 75₁,
75 _TwoGoing up. At that time, the flight contained in the air
Spray is draining step 75₁, 75 _TwoI will be stopped from progressing
And only air is drained₁, 75_TwoPass through
Will flow into the engine room 36 and the engine E
It is used for intake and cooling of each part.

As shown in FIGS. 3 and 14 to 17, on the upper surface of the upper belt cover 11, a belt chamber 6 is provided.
8, a first communication cylinder 115 (first communication portion) having a rectangular shape is protruded, and a sealing member 117 made of urethane foam is collectively provided around the upper opening. On the other hand, on the right side of the guide plate 75, a second rectangular communication tube 116 (first communication portion) extending vertically and having an upper end abutting on the inner surface of the engine cover 4.
There are formed, on the rear wall, the notch communicating with exist the rear opening 4 ₁ and the upward step 72 of the engine cover 4 1
18 are provided. Then, the first and second communication cylinders 115,
Numerals 116 are joined and separated from each other via a seal member 117 in accordance with attachment / detachment of the engine cover 4 to / from the under case 3.

The opening 10 ₁ and the slit 1
0 air introduced ₂ into the belt chamber 68 through the is discharged to the rear opening 4 ₁ out through the ventilation communication passage 123, the second communication tube 116 and the notch 118 to be described later in the first communication tube 115 That is, ventilation of the belt chamber 68 can be performed. At this time, the notch 118 of the second communication cylinder 116
, Since than the rear opening 4 ₁ occupies the position of the upper, second communicating droplets arriving at rear opening 4 ₁ barrel 116
Can be prevented from entering.

Next, the structure of the intake system of the engine E will be described with reference to FIGS.

An intake silencer 76 is fixed to the front of the crankcase 7 with three bolts 77. The intake silencer 76 includes a box-shaped main body 78 and a duct 79 connected to a left side surface of the main body 78. The duct portion 79 has an intake opening 79 ₁ that opens downward at the lower end thereof.
Provided with a, and a communicating hole 79 ₂ communicating with the internal space of the main body portion 78 at its upper end. Throttle body 80 arranged on the right side of main body 78 of intake silencer 76
Is connected to the main body 78 via a flexible short air intake duct 35.

The throttle body 80 is connected and fixed to an intake manifold 85 described below. Elbow 81, surge tank 82, and four intake pipes 83a, 83b, 83
An intake manifold 85 integrally provided with c and 83d and a mounting flange 84 is arranged along the right side of the engine E. The elbow 81 changes the flow of intake air from a flow along the front surface of the crankcase 7 to a flow along the right side surface of the crankcase 7 by approximately 90 °, and may be a duct having flexibility. In this embodiment, the surge tank 82, the intake pipes 83a, 83b, 83c, 83d and the mounting flange 8 are provided for supporting and fixing the throttle body 80.
4 and one.

The elbow 81 and the support of the intake manifold 85
The connection part of the surge tank 82 is the upper end of the surge tank 82
And the size is smaller in the vertical direction than the lower end.
And the bolt 86₁, 86_TwoWith a loose hole
Two brackets 86_ThreeAnd the crankcase 7
Is fixed to the right side wall of the
A bolt 87 is formed on the right side surface of the cylinder head 8 by a bolt 87.
Air manifold mounting surface 8 ₁Fixed to

Next, the structure of the fuel supply device for the engine E will be described with reference to FIGS.

Two low-pressure fuel pumps 88 composed of plunger pumps are provided in parallel on the rear surface of the head cover 9. These low-pressure fuel pumps 88 allow fuel to be supplied from a main fuel tank (not shown) installed in the ship. Supply pipe L ₁
The fuel sucked through is supplied to the auxiliary fuel tank 89 is disposed on the right side of the engine E through the low pressure fuel filter and the fuel supply pipe L ₂ (not shown). As shown in FIG. 5, a pump drive rocker arm 103 is coaxially supported on an intake rocker arm shaft 102 supporting an intake rocker arm 101, and one end of the pump drive rocker arm 103 is provided on the cam shaft 39. Pump cam 1
04 and the other end engages the plunger 105 of each low pressure fuel pump 88. Thus, the low-pressure fuel pump 88 is driven by the cam shaft 39.

As shown in FIG. 6 to FIG.
The auxiliary fuel tank 89 is a lower tank body 89₁And its
Upper cap 89 bonded to the upper end_TwoAnd split into two
Yes, tank body 89₁The first block extending long backward
Racket 130₁And a relatively short second protrusion protruding forward.
Racket 130_TwoAnd a relatively short third protrusion protruding upward.
Racket 130_ThreeAre integrally formed. These braquets
130₁, 130 _Two, 130_ThreeThe mounting hole at the tip
Each of the elastic grommets 131 is attached,
The first and second brackets 13 via the helmet 131
0₁, 130_TwoIs the fourth intake pipe 83d and the cylinder blow
First and second mounting bosses 132 formed on the hook 6₁, 13
2_TwoBolt 129₁, 129_TwoInstalled by each
The third bracket 131 is provided with a surge tank 82.
Is supported by a support pin 133 protruding from the side surface. Bullet above
Grommet 131 is provided from engine E to auxiliary fuel tank
To prevent vibration transmission to 89 and to suppress heat conduction
Can be.

Inside the auxiliary fuel tank 89, a float valve 90 for adjusting the level of the stored fuel is accommodated. The float valve 90 includes a shutoff valve 108 to the fuel supply pipe L ₂ extending from the low pressure fuel pump 88 is provided in a portion that is connected to the auxiliary fuel tank 89, the on-off valve to lift to follow the fuel level And a float 109 for opening and closing the opening 108. When the fuel level drops below a prescribed level, the on-off valve 108 opens to open the low-pressure fuel pump 88.
Is introduced into the auxiliary fuel tank 89 and rises above a prescribed level, the on-off valve 108 closes to shut off the reception of fuel from the low-pressure fuel pump 88.

Attached to the auxiliary fuel tank 89 are a high-pressure fuel pump 91 having an axis extending in the front-rear direction immediately below the tank, and a high-pressure fuel filter 92 having an axis extending in the up-down direction immediately after the tank.

The high-pressure fuel pump 91 is entirely covered with a cylindrical heat insulating material 234 formed by abutting a pair of semi-cylindrical bodies 134a and 134b. In the case of the illustrated example, the heat insulating material 134 is formed by molding a laminate of a nonwoven fabric and a foamed melamine resin. A pair of front and rear annular grooves 135 are formed on the heat insulating material 134 with the central thick portion interposed therebetween, and a rubber band 137 is wound around each annular groove 135, and a steel plate mounting engaged with the outer periphery thereof is provided. Band 13
6, the high-pressure fuel pump 91 is fastened and attached to the outer surface of the bottom wall of the auxiliary fuel tank 89. That is, a pair of front and rear hook engaging portions 138 is provided on one lower side of the auxiliary fuel tank 89.
In addition, a pair of front and rear mounting bosses 139 are integrally formed on the other side of the lower portion, and the hook 136a at one end of each mounting band 136 is engaged with the corresponding hook engaging portion 138, and each mounting band 136 is formed. Is fixed to the corresponding mounting boss 139 with a bolt 140, so that the high-pressure fuel pump 91 is fastened to the outer surface of the bottom wall of the auxiliary fuel tank 89. By disposing the high-pressure fuel pump 91 immediately below the auxiliary fuel tank 89 in this manner,
A fuel outlet pipe 141 protruding from the front surface of the bottom and a fuel inlet pipe 91i protruding from the front end face of the pump 91 are arranged close to each other, and they are connected by a low-pressure fuel pipe 143 as short as possible.

The high-pressure fuel filter 92 is connected to the auxiliary fuel tank 8
Attached to the first outer surface of the bracket 130 ₁ 9.
That is, the first bracket 130 ₁ has the mounting boss 145 and the hook engaging portion 146 formed before and after, and the steel plate mounting band 148 engaged with the outer periphery of the high-pressure fuel filter 92 via the rubber band 147. Hook 148a at one end
The while engaged with the hook engaging portion 146, by fixing to the mounting boss 145 at the other end the bolt 149, the high-pressure fuel filter 92 is clamped to the first outer surface of the bracket 130 ₁ of the auxiliary fuel tank 89 . Thus, the fuel outlet pipe 91o projecting from the rear end face of the high-pressure fuel pump 91 and the fuel inlet pipe 92i projecting from the lower end face of the high-pressure fuel filter 92 are arranged close to each other. It is connected by a short high-pressure fuel pipe 144.

Thus, the high pressure fuel pump 91
34, immediately after the operation of the engine E is stopped, even if the ambient temperature inside the engine cover 4 temporarily rises,
Heating of the atmosphere due to high heat can be avoided, bubbles are prevented from being generated in the fuel remaining inside the pump, and fuel can be appropriately supplied to the fuel injection valve 94 when the engine E is restarted. it can.

Mounting flange 84 of intake manifold 85
The, the fuel rail 93 is fixed by a plurality of bolts 113, four cylinders 12 are to four fuel injection valves 94 is fixed corresponding to the fuel supply pipe L ₄ from the high-pressure fuel filter 92 The fuel supplied to the lower end of the fuel rail 93 is distributed to the four fuel injection valves 94. A regulator 95 provided at the upper end of the fuel rail 93 adjusts the pressure of the fuel supplied to the fuel injection valve 94,
The excess fuel through the return pipe L ₅ fuel auxiliary fuel tank 8
Reflux to 9. To adjust the set pressure of the regulator 95, the regulator 95 and the surge tank 82 is connected through a negative pressure pipe L _6.

When assembling the engine E,
A high-pressure fuel pump 91 and a high-pressure fuel filter 92 are previously attached to an auxiliary fuel tank 89 in an auxiliary assembly line to constitute a fuel auxiliary machine assembly.
Is attached to the intake manifold 85 to form an assembly of the manifold and the fuel auxiliary equipment, and this is assembled to the main body of the engine E in the main assembly line, so that the number of assembly steps in the main assembly line is reduced. Can be enhanced.

As is apparent from FIGS. 7 to 9, an air vent chamber 151 is formed in the upper part of the auxiliary fuel tank 89. The air vent chamber 151 has an upper cap 89 ₂
A pair of partitions 1 protruding from the ceiling surface of
52, and a baffle plate 153 joined to the lower end surfaces of the two partition walls 152. The baffle plate 153 has a through hole 154 that communicates the center of the air vent chamber 151 with the lower space. ing.

On the ceiling wall of the auxiliary fuel tank 89, the above air
A pair of first and second pairs each having one end opened to the vent chamber 151.
2 air vent hole 155₁, 155_TwoAnd these airbens
155₁, 155_TwoAir that connects the other end of the
A vent hole 156 is formed. At that time, the first and second
Air vent hole 155₁, 155_TwoIs one end of them
a ₁, A_TwoBut in the left-right direction of the auxiliary fuel tank 89
The center of the auxiliary fuel tank 89 in the front-rear direction as far as possible
(In the example shown, slightly behind the center)
151, and one of the first and second air vent holes
155₁, 155_TwoThe other end b of₁, B_TwoThe other airben
155_Two, 155₁One end of_Two, A₁Same as left and right
Each is formed in a hook shape so as to be disposed on the side. So
At this time, the first and second air vent holes 155₁, 155_Two
And the merged air vent hole 156 are arranged on the same horizontal plane.
Top cap 89_TwoThick part 89_Twoa
They are to be rilled, and their openings are blind plugs 157
Closed. As described above, the first and second air vent holes are provided.
155₁, 155_TwoAnd the same air vent hole 156
By arranging on a horizontal plane, the upper cap 89_Twoof
Thick part 89_TwoThe thickness increase of a can be minimized
You.

_On the upper surface of the upper cap 892, a joint 121 connected to the merging air vent hole 156 is erected, and this joint 121 is connected to an air vent pipe 120 by a joint 122 projecting from the lower surface of the lower belt cover 10. Connected via

Referring again to FIGS. 14 to 17, the first and second communication tubes 11 and 11 are attached to the upper and lower belt covers 10, respectively.
5, a communication passage 123 for ventilation connected to the belt chamber 68;
A partition 125 is formed, which is partitioned into an air vent communication passage 124 connected to the joint 122.

In the auxiliary fuel tank 89, the stored fuel
According to the increase or decrease of the fuel, the through hole 1 of the baffle plate 153
54, air vent chamber 151, first and second air vent holes 1
55 ₁, 155_TwoAir vent hole 156, air vent
Pipe 120, air vent communication passage 124, and second communication cylinder
Rear opening 4 through an air vent path 116 ₁
Because it can breathe between, the inside is almost at atmospheric pressure
And supply of fuel to the fuel injection valve 94 without hindrance.
It can be carried out. In addition, the auxiliary fuel tank 89 is
Heat from the regulator E
Excess fuel returns to the auxiliary fuel tank 89, etc.
As a result, fuel vapor is generated in the auxiliary fuel tank 89.
And the fuel vapor rises in the air vent path,
From the notch 118 of the two-way cylinder 116 to the top of the engine cover 4
Rear opening 4₁Is smoothly discharged to the outside through
You. Thus, the fuel vapor is sucked into the engine E.
Can prevent the deterioration of the exhaust properties
You. In this case, a communication passage for air vent through which fuel vapor passes
Reference numeral 124 denotes the ventilation communication passage 12 in the first communication cylinder 115.
3 and the partition wall 125, the fuel vapor
Inflow into the belt chamber 68 can also be prevented.

Further, the ventilation communication passage 123 and the air vent communication passage 124 are formed in the common first communication cylinder 115 so that the second communication cylinder 11
6, the communication part is sufficient at one place, and the sealing member 117 for sealing the communication part is also one.
Since only one piece is required, it is possible to contribute to simplification of the structure.

If the auxiliary fuel tank 89 is greatly inclined in the front-rear direction due to pitching of the hull or tilting of the outboard motor, the fuel stored in the tank 89 is shifted to the front or rear of the tank 89. Therefore, the tank 8
The opening ends a ₁ , a _{2 of} the first and second air vent holes 155 ₁ , 155 ₂ arranged at the substantially central portion in the front-rear direction of the air vent chamber 151 do not sink below the liquid level of the stored fuel. Further, when the auxiliary fuel tank 89 is greatly inclined due to rolling of the hull, steering of the outboard motor O in a tilted state, or the like, the fuel stored in the tank 89 is removed.
Of the first and second air vents 155 ₁ and 155 ₂ , the open end a ₁ or a ₂ to the air vent chamber 151 sinks below the level of the stored fuel. The other open end a ₂ or a ₁ can continue to open in the upper space of the tank 89. Moreover, even if one end a ₁ or a ₂ of one air vent hole sinks below the stored fuel liquid level, the other end b ₁ or b ₂ of the air vent hole occupies a position above the stored fuel liquid level. The stored fuel does not invade until. Therefore,
Regardless of the inclination of the outboard motor O, the inside of the auxiliary fuel tank 89 always has at least one of the air vent holes 155 ₁ or 155 ₂ continuously opening to the upper space thereof, the confluent air vent hole 156 and the air vent Tube 120
It is possible to breathe through the like, can be discharged fuel vapor generated in the said tank 89, the rear opening 4 ₁ outside without flowing out the stored fuel. Moreover, since only one air vent pipe 120 is required to be connected to the auxiliary fuel tank 89, the number of parts is small and the structure can be simplified.

Further, the first and second air vent holes 155 ₁ ,
155 open end a, b of ₂ to the air vent chamber 151, so covered by the baffle plate 153, also by waving of the surface of liquid fuel in the auxiliary fuel tank 89, the first and second air vent holes 155 ₁ of the fuel, Infiltration into 155 ₂ can be suppressed by the baffle plate 153.

As shown in FIG. 7 and FIG.
Cap 89_TwoThe fuel return pipe L_FiveIs connected
Connection 159 and the fuel return hole 160 connected thereto
Is provided. The fuel return hole 160 is provided in the air vent.
So that it opens to the front of the front partition 152 of the
While the baffle plate 153 is
It is formed so as to protrude long in front of the wall 152. did
The fuel return pipe K _FiveHigh temperature and high pressure surplus fuel passed through
The battery in the auxiliary fuel tank 89 through the fuel return hole 160.
Because it will be exhaled on the full plate 153,
Bubbles contained in the fuel are placed on the baffle plate 153.
And mix air bubbles into the fuel stored in the auxiliary fuel tank 89.
Entrance can be avoided as much as possible. In addition, the return fuel
Float valve to prevent falling to float 109
90 can be prevented from malfunctioning.

Next, a cooling device for the engine E and the auxiliary fuel tank 89 will be described with reference to FIGS. 3, 8, 10 and 13.

The engine E has a main water jacket 162 for cooling the cylinder block 6 and the cylinder head 8 and a sub water jacket 163 for cooling the lubricating oil gallery.
Is provided with a water jacket 180 for its cooling. The entrance of the main water jacket 162 is
4, the water intake 16 of the extension case 1
5 (see FIG. 1), and a water pump 166 driven by the drive shaft 17 is interposed in the main water passage 164. The outlet of the main water jacket 162 is connected to a first drainage channel 168 ₁ via a thermo valve 167, and the downstream end thereof is opened into the extension case 1.
The inlet of the main water jacket 162 and the first drainage channel 1
68 ₁ and is connected via a bypass water passage 170 having a first relief valve 169 _1, the first relief valve 169 ₁ is adapted to open when the pressure of the water passage 164 is equal to or greater than a prescribed value.

In the middle of the main channel 164, a first branch channel 171 is provided.
Is connected to the inlet of the auxiliary water jacket 163, and the outlet thereof is connected to the extension case 1.
The second drainage channel 168 ₂ opening the downstream end is connected to the inside,
The second drainage channel 168 ₂ has a sub water jacket 1
63 water pressure of the second relief valve 169 ₂ is provided which opens when equal to or greater than a prescribed value. This second relief valve 169 ₂
Opening pressure of is set first relief valve 169 ₁ lower.

A second branch water passage 172 is connected to the first branch water passage 171, which is connected to an inlet pipe 175 of the water jacket 180 of the auxiliary fuel tank 89, and an orifice 174 is provided in the middle thereof. Outlet pipe 176 of the water jacket 180 is connected to _two said second drainage channel 168. Further, a water detection passage 177 connected to a water detection hole 178 opened on the outer surface of the undercase 3 is connected to the second branch water passage 172 upstream of the orifice 174. The water detection passage 177 is located below the water jacket 180 of the auxiliary fuel tank 89 even when the outboard motor O is tilted up.

When the engine E is operating, the drive shaft 17
The water pump 166 driven by the
The cooling water pumped from 5 is supplied to the main channel 164, the first branch channel 171, the second branch channel 172, and the third branch channel 173. The cooling water supplied to the water channel 164, at the time of warming up of the engine E thermo valve 167 is closed, the warming-up of the engine E flows through the bypass water passage 170 pushes and opens the first relief valve 169 ₁ Facilitate. After the warm-up, when the thermo valve 167 opens, the first relief valve 16
9 ₁ is closed, now the cooling water flows through the main water jacket 162 can cool the engine E.

The cooling water supplied to the first branch water passage 171 is
The water flow is always the first, regardless of whether the engine E is cold or warm.
Relief valve 169_TwoVice water jacket while pushing open
163 to cool the oil gallery for lubrication
You. In addition, the first relief valve 169 _TwoValve opening pressure is relatively low
Since the setting has been made, the secondary
Even if the water pressure of the water jacket 163 drops, the first
Leaf valve 169_TwoCan keep open.

The second and third branch waterways 172, 173
Is always flowing through the water jacket 180 of the auxiliary fuel tank 89 to cool the tank 89 irrespective of whether the engine E is cold or warm, and the remainder passes through the water passage 177. The water is discharged from the test hole 178.

The bypass water channel 170 and each water jacket 1
The cooling water having passed through 62, 163, 180 is discharged into the extension case 1 through the first drain passage 168 ₁ or the second drain passage 168 _2, and into the water from the boss hollow portion of the propeller 20 together with the exhaust gas of the engine E. Is discharged.

As shown in FIGS. 8 and 10, the water jacket 180 comprises a side wall 89 ₁ a of the tank body 89 ₁ of the auxiliary fuel tank 89 adjacent to the engine E and a side cap 181 joined thereto. Is defined between The water jacket 180 is formed to extend long in the front-rear direction.
5. An outlet pipe 176 is attached to the upper part, and the inlet pipe 1
75, the third branch channel 173 is connected to the outlet pipe 17.
6 is connected to the second drainage channel 168 ₂ . In addition, in the water jacket 180, the inlet pipe 175 and the outlet pipe 1 are provided.
A water flow guide wall 184 extending horizontally in the front-rear direction is disposed at an intermediate portion of the horizontal direction 76. The water flow guide wall 184 is formed of a pair of right and left ribs 184a integrally formed on the opposing surfaces of the side wall 89 ₁ a and the side cap 181. , 184b, a small gap 185 is provided between the water jacket 180 and the front end wall, and a large gap 186 is provided between the water jacket 180 and the rear end wall.

Therefore, during the operation of the engine E, most of the cooling water flowing into the water jacket 180 from the third branch water channel 173 through the inlet pipe 175 largely moves around the water flow guide wall 184 so as to pass through the large gap 186. That is, it is possible to efficiently cool the auxiliary fuel tank 89 by flowing the entire water jacket 180 without stagnation, thereby effectively cooling the fuel in the tank 89 and minimizing the generation of fuel vapor. Can be. Cooling water passing through the water jacket 180 flows out from the outlet pipe 176 to the second drain pipe 168 _2.

When the operation of the engine E is stopped, the operation of the water pump 166 is also stopped, so that the main water jacket 162 and the sub water jacket 16 of the engine E are stopped.
The cooling water in 3 can mainly flow down the main channel 164 and flow out of the water intake 165 to the outside. The cooling water in the water jacket 180 of the auxiliary fuel tank 89 is supplied to the inlet pipe 175, the third branch channel 173, and the water detection channel 17.
7 can flow down to the outside through the test hole 178.

In this case, in particular, the inlet pipe 175 is provided at the lower part of the front end wall of the water jacket 180 of the auxiliary fuel tank 89.
Is provided, even if the outboard motor O is in the tilted-up state, the front end wall of the water jacket 180 comes below the rear end wall, and the inlet pipe 175 is located at the lowermost position. In addition, the water above the water flow guide wall 184 can also move to the inlet pipe 175 through the small gap 185, and the water detection passage 177 is provided below the inlet pipe 175.
The cooling water in the water jacket 180 is
From 75, it can flow out to the water detection channel 177. By draining water from the water jackets 162, 163, and 180 in this manner, it is possible to prevent rusting of the inner surfaces of the water jackets 162, 163, and 180 due to residual water and damage to various parts due to freezing of the residual water.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof. For example, the first and second air vent holes 155 ₁ and 155 ₂ may be formed such that they cross each other in an X shape. In this case, it is a matter of course that both air vent holes 155 ₁ and 155 ₂ are not communicated at the intersection.

[0062]

As described above, according to the first aspect of the present invention, the excess fuel recirculating from the fuel injection valve side of the engine in the engine room of the outboard motor is received and stored in the engine room of the outboard motor. An auxiliary fuel tank for separating fuel vapor from the fuel is provided, and an air vent pipe extending upward in communication with an upper space inside the auxiliary fuel tank is connected to the auxiliary fuel tank.
In the fuel vapor separation device for an outboard motor, a first end opening to the upper space is provided on a ceiling wall of an auxiliary fuel tank.
And a second air vent hole, and a merging air vent hole communicating the other ends of the first and second air vent holes. The ends of the first and second air vent holes are connected to each other in the left-right direction of the auxiliary fuel tank. And the other end of each of the first and second air vent holes is disposed on the same side in the left-right direction as one end of the other air vent hole. Since the air vent pipe is connected to the auxiliary fuel tank, even when the outboard motor is tilted in all directions, the auxiliary fuel tank has at least one of the first and second air vent holes exposed above the stored fuel level, the merged air vent hole, and It is possible to breathe through the air vent pipe, and the fuel vapor generated in the auxiliary fuel tank is
The stored fuel can be discharged without flowing out.
Moreover, since only one air vent pipe is required to be connected to the auxiliary fuel tank, it can contribute to simplification of the structure.

According to the second feature of the present invention, the first and second air vent holes are formed in a hook shape, and the first and second air vent holes and the merged air vent hole are arranged on the same horizontal plane. , The first and second air vent holes and the merged air vent hole are formed on the same plane, and the air vent holes are formed in the ceiling wall of the auxiliary fuel tank while minimizing the increase in the thickness of the ceiling wall. be able to.

[Brief description of the drawings]

FIG. 1 is an overall side view of an outboard motor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a view in the direction of arrows in FIG. 2;

FIG. 4 is a view in the direction of arrows in FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 3;

FIG. 6 is an enlarged sectional view of a main part of FIG. 3;

FIG. 7 is a view taken in the direction of arrow 7 in FIG. 6;

8 is a view taken in the direction of arrow 8 in FIG. 7;

9 is a sectional view taken along line 9-9 in FIG. 7;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 7;

11 is a sectional view taken along line 11-11 of FIG. 7;

FIG. 12 is a sectional view taken along line 12-12 of FIG. 7;

FIG. 13 is a cooling water circuit diagram.

FIG. 14 is a view taken in the direction of arrow 14 in FIG. 3;

FIG. 15 is a sectional view taken along line 15-15 of FIG. 14;

16 is a sectional view taken along line 16-6 of FIG.

FIG. 17 is a sectional view taken along line 17-17 of FIG. 14;

[Explanation of symbols]

36 ··· Engine room 89 ··· Auxiliary fuel tank 94 ··· Fuel injection valve 120 ··· Air vent pipe 155 ₁ ··· First air vent hole 155 ₂ ··· Second air vent hole 156 ··· Merge one end of the air vent hole E · · · · · engine O · · · · · outboard motor a ₁ · · · · first air vent hole at one end of the (open end) a ₂ · · · · second air vent hole (opening end) b ₁ ... the other end of the first air vent hole b ₂ ... the other end of the second air vent hole

Claims (2)

[Claims] An outboard motor (O) engine room (36).
And an auxiliary fuel tank (89) for receiving excess fuel recirculated from the fuel injection valve (94) side of the engine (E) in the engine room (36) and separating fuel vapor from stored fuel. A fuel vapor separation device for an outboard motor, wherein an air vent pipe (120) extending upward in communication with an upper space inside the auxiliary fuel tank (89) is connected to the auxiliary fuel tank (89); to the each end into the upper space (a _1, a ₂₎ the first and second air vent hole opened to (155 _1, 155 _2), the first and second air vent holes (155 _1, 155 ₂₎ The other end (b ₁ , b ₂ )
A first and second air vent holes (155 ₁ , 155 ₂ ) formed with a merged air vent hole (157) communicating with each other;
One end (a _1, a ₂₎ and spaced apart from the auxiliary fuel tank in the lateral direction of the auxiliary fuel tank (89) to each other (89)
And the other end (b ₁ , b ₂ ) of each of the first and second air vent holes (155 ₁ , 155 ₂ ) is connected to the other air vent hole (155 ₂ , 15 ₂ ).
5 ₁ ) and one end (a ₂ , a ₁ ) on the same side in the left-right direction
The air vent pipe (12) is inserted into the merged air vent hole (157).
0) A fuel vapor separation device for an outboard motor, wherein 2. The device according to claim 1, wherein the first and second air vent holes (155 ₁ , 155 ₂ ) are formed in a hook shape, and the first and second air vent holes (155) are formed.
₁ , 155 ₂ ) and a combined air vent hole (157) arranged on the same horizontal plane.