JPH1191689A - Fuel feeding system in outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent bubbles from generating in the residual fuel in a high- pressure fuel pump even if the ambient temperature under the engine cover temporarily rises immediately after the engine is shut off, in the fuel feeding system in an outboard motor. SOLUTION: In the fuel system that contains an spare fuel tank 89 that can receive excess fuel returned from the fuel injection valve 94 side of an engine E, a high-pressure fuel pump 91 that sends the stored fuel of this spare fuel tank 89 under pressure to the fuel injection valve 91 of the engine E, and a fuel filter 92 that filters the discharged fuel of this high-pressure fuel pump 91 under the engine cover, the high-pressure fuel pump 91 is covered with a heat insulator 134 that protects it from surrounding heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for an outboard motor, and more particularly, to an auxiliary device capable of receiving surplus fuel recirculated from a fuel injection valve side of an engine in an engine cover covering an engine driving a propeller. The present invention relates to an improvement including a fuel tank, a high-pressure fuel pump for pumping fuel stored in an auxiliary fuel tank to a fuel injection valve of an engine, and a fuel filter for filtering fuel discharged from the high-pressure fuel pump.

[0002]

2. Description of the Related Art A fuel supply device for such an outboard motor is:
For example, it is already known as disclosed in Japanese Patent Application Laid-Open No. 1-215694.

[0003]

Generally, in an outboard motor, immediately after the operation of the engine is stopped, the ambient temperature in the engine cover may temporarily rise due to the stop of the cooling device. In this case, in the conventional fuel supply device for an outboard motor, the high-pressure fuel pump is heated by the high heat of the atmosphere, and there is a possibility that bubbles may be generated in the residual fuel inside the pump.

The present invention has been made in view of such circumstances, and even if the ambient temperature inside the engine cover temporarily rises immediately after the operation of the engine is stopped, bubbles remain in the residual fuel in the high-pressure fuel pump. It is an object of the present invention to provide a fuel supply device in the outboard motor, which does not generate any fuel.

[0005]

In order to achieve the above object, the present invention provides an auxiliary fuel capable of receiving surplus fuel recirculated from a fuel injection valve side of an engine in an engine cover covering an engine for driving a propeller. In a fuel supply device for an outboard motor, which contains a tank, a high-pressure fuel pump for pumping fuel stored in the auxiliary fuel tank to a fuel injection valve of an engine, and a fuel filter for filtering fuel discharged from the high-pressure fuel pump, A first feature is that the high-pressure fuel pump is covered with a heat insulating material that blocks heat from the surroundings.

According to the first feature, even if the temperature of the atmosphere in the engine cover is temporarily increased immediately after the stop of the operation of the engine, the heat of the atmosphere is blocked by the heat insulating material to heat the high-pressure fuel pump. Can be prevented, and the generation of bubbles in the residual fuel in the inside can be avoided.

[0007] In addition to the above-mentioned features, the present invention provides a high-pressure fuel pump attached to an auxiliary fuel tank so that a fuel outlet of the auxiliary fuel tank and a fuel inlet of the high-pressure fuel pump are connected to each other by a fuel pipe. This is a second feature.

According to the second feature, an assembly of the auxiliary fuel tank and the high-pressure fuel pump can be constituted,
The assemblability of the outboard motor is improved, and the length of the fuel pipe connecting between the fuel outlet of the auxiliary fuel tank and the fuel inlet of the high-pressure fuel pump is shortened as much as possible. The effect of heat from the atmosphere can be reduced.

Further, in addition to the first or second feature, the present invention further provides a bracket for attaching the auxiliary fuel tank to the engine, and a first bracket for attaching the high-pressure fuel pump and the fuel filter to the tank, respectively. The third feature is that the second mounting means and the second mounting means are provided.

According to the third aspect, an assembly of the auxiliary fuel tank, the high-pressure fuel pump and the fuel filter can be formed, and the assemblability of the outboard motor is further improved.

[0011]

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

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. 3 is a view taken in the direction of arrow 3 in FIG. 2, and 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, and 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.

The 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, 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 is fixed. 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 resilience 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.

Two bolts 5 are provided on the upper surface of the crankcase 7.
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 is 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 FIG. 3 and FIGS. 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.

On the rear surface of the head cover 9, two low-pressure fuel pumps 88 composed of plunger pumps are provided in parallel, and these low-pressure fuel pumps 88 supply fuel from a main fuel tank (not shown) installed on 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 FIGS. 6 to 12,
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 of
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 protruding from the rear end face of the high-pressure fuel pump 91 and the fuel inlet pipe 92i protruding from the lower end face of the high-pressure fuel filter 92 are arranged close to each other. They are connected by a 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 clear 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. A pair of first and second air vent holes 155 ₁ , 155 ₂ are opened in the ceiling surface of the air vent chamber 151, and their open ends are separated from each other as much as possible in the left-right direction, and both are connected to the auxiliary fuel tank 8.
9 is arranged so as to occupy a position slightly rearward from the center in the front-rear direction. These two air vent holes 155 ₁ and 155 ₂
Communicate with each other via a merged air vent hole 156 that is separated from the air vent chamber 151 in the front-rear direction. These first, second air vent hole 155 _1, 155 ₂ and the merging air vent hole 156, intended to be drilled in the ceiling wall of the upper cap 89 _2, each working port is closed by the blind plug 157.

_On the upper surface of the upper cap 892, a joint 121 connected to the merging air vent hole 156 is provided upright. 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.

When the hull is moored, if the outboard motor O is tilted up and steered to the right or left, or if the outboard motor O is removed from the hull and falls down, the auxiliary fuel tank 89 Although the fuel level remaining in the first and second air vent holes 37a, 37
Even if one open end of b is submerged below the fuel level, the other open end is always exposed above the liquid level. Therefore, the auxiliary fuel tank 8
9 inside the while the air vent hole 37a or 37b of exposing the opening end on the fuel level, it is possible to continue to breathe through the air vent path and the rear opening 4 ₁ connected to it, the fuel from the tank 89 Outflow can be prevented. This means that the inside of the tank 89 can breathe without any trouble even when the ship in flight is tilted left and right.

The first and second air vent holes 37a, 37
Since the open end of 7b is disposed slightly rearward from the center of the auxiliary fuel tank 89 in the front-rear direction, even if the outboard motor O is tilted up during the shallow voyage, the first and second air vent holes 37a, 37b are formed. The open end of 37b does not sink below the fuel level. Therefore, also in this case, breathing inside the tank 89 is ensured.

Further, the first and second air vent holes 37a,
Since the open end of the fuel tank 37b is covered with the baffle plate 153 in the air vent chamber 151, the first and second fuels of the fuel are also generated by the wave of the fuel level in the auxiliary fuel tank 89.
Infiltration into the air vent holes 37a and 37b 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 includes 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 drain passage 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 channel 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 detour 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.
Water flow guide plate 184 back and forth direction extending horizontally in the intermediate portion 76 is disposed, the flow guide plate 184, the side wall 89 ₁ a and rib pair which is integrally formed on the opposed surfaces of the side cap 181 184a , 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 goes around the water flow guide plate 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 when the outboard motor O is in a 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 substantially lowermost position. In addition, the water above the water flow guide plate 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.

FIG. 18 shows a second embodiment of the present invention, in which a water jacket 180 of an auxiliary fuel tank 89 is provided.
, An inlet pipe 175 is provided above the front end wall, and an outlet pipe 176 is provided below the front end wall. In the tilted state of the outboard motor O, the second drainage channel 1
Except that connects the outlet tube 176 to 68 _2, has the same configuration as that of the previous embodiment, the description thereof is omitted for the portions corresponding to the figure, first embodiment are denoted by the same reference numerals.

In the case of this embodiment, when the outboard motor O is tilted up, the outlet pipe 176 is substantially at the bottom in the water jacket 180, so that the cooling water in the water jacket 180 is less than when the engine E is operating. Similarly continue to flow out from the outlet pipe 176 to the second drain passage 168 _2, it does not remain in the water jacket 180.

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.

[0066]

As described above, according to the first aspect of the present invention, an auxiliary fuel tank capable of receiving surplus fuel recirculated from a fuel injection valve side of an engine in an engine cover for covering an engine for driving a propeller. A fuel supply device for an outboard motor, containing a high-pressure fuel pump for pumping fuel stored in the auxiliary fuel tank to a fuel injection valve of an engine, and a fuel filter for filtering fuel discharged from the high-pressure fuel pump. Since the high-pressure fuel pump is covered with a heat insulating material that blocks heat from the surroundings, even if the temperature of the atmosphere inside the engine cover temporarily rises immediately after the operation of the engine is stopped, the high heat of the atmosphere is blocked by the heat insulating material. This prevents heating of the high-pressure fuel pump and avoids the generation of air bubbles inside the high-pressure fuel pump.
Proper fuel supply to the fuel injector is ensured.

Further, in addition to the above-mentioned features, the present invention provides a high-pressure fuel pump mounted on an auxiliary fuel tank such that the fuel outlet of the auxiliary fuel tank and the fuel inlet of the high-pressure fuel pump are connected to each other by a fuel pipe. Therefore, an assembly of the auxiliary fuel tank and the high-pressure fuel pump can be formed, so that the assemblability of the outboard motor is improved, and the fuel connecting the fuel outlet of the auxiliary fuel tank and the fuel inlet of the high-pressure fuel pump is improved. By shortening the length of the tube as much as possible, it is possible to reduce the influence of heat on the fuel flowing through the fuel tube from the atmosphere in the engine cover.

According to a third feature of the present invention, a bracket for mounting the auxiliary fuel tank to the engine, and first and second mountings for mounting the high-pressure fuel pump and the fuel filter to the tank, respectively. With the provision of the means, an assembly of the auxiliary fuel tank, the high-pressure fuel pump and the fuel filter can be formed, and the assemblability of the outboard motor can be further improved.

[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;

FIG. 18 is a cooling water circuit diagram showing a second embodiment of the present invention.

[Explanation of symbols]

E ... Engine O ... Outboard motor 2 ... Mount case 4 ... Engine cover 20 ... Propeller 89 ... Auxiliary fuel tank 91 ... High-pressure fuel pump 92 Fuel filter 94 Fuel injection valve 130 _{1 to} 130 ₃ Bracket 134 Heat insulating material 136 First mounting means (mounting band) 141 Fuel outlet of auxiliary fuel tank 143: fuel pipe 148: second mounting means (mounting band)

Claims (3)

[Claims] An auxiliary fuel tank capable of receiving surplus fuel recirculated from a fuel injection valve (94) side of an engine (E) in an engine cover (4) covering an engine (E) driving a propeller (20). (89), a high-pressure fuel pump (91) for pumping the fuel stored in the auxiliary fuel tank (89) to the fuel injection valve (94) of the engine (E), and filtering the fuel discharged from the high-pressure fuel pump (91). A high-pressure fuel pump (91) covered with a heat insulating material (134) for shutting off heat from the surroundings. Fuel supply device for outboard motor. 2. A fuel pipe (143) according to claim 1, wherein a fuel outlet (141) of the auxiliary fuel tank (89) and a fuel inlet (91i) of the high-pressure fuel pump (91) are brought close to each other. A fuel supply device for an outboard motor, wherein a high-pressure fuel pump (91) is attached to an auxiliary fuel tank (89) so as to be connected. 3. The auxiliary fuel tank (89) according to claim 1, further comprising: a bracket (130 _{1 to} 130 ₃ ) for mounting the auxiliary fuel tank to the engine (E); A fuel supply device for an outboard motor, comprising first and second mounting means (136, 148) for mounting a fuel pump (91) and a fuel filter (92), respectively.