JP3660053B2 - Outboard motor cooling structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling structure for an outboard motor attached to a small boat such as a motor boat, a yacht or a fishing boat, and more particularly to cooling an oil pan.
[0002]
[Prior art]
Conventionally, in an outboard motor, an engine cylinder, a combustion chamber, and an exhaust passage are cooled by water sucked from the outside of the outboard motor, that is, cooling water. The engine oil that lubricates the engine is stored in the oil pan. A cooling water reservoir is provided around the oil pan, and the oil pan is cooled by the cooling water in the cooling water reservoir. ing. The cooling water used for cooling the engine cylinder, the combustion chamber, and the exhaust passage flows into the cooling water reservoir. The temperature of the cooling water flowing into the cooling water reservoir is not constant, and varies considerably as it rises and falls.
[0003]
For example, when a thermostat and a pressure valve are provided in a cooling water channel through which the cooling water flows, the cooling water flows into the cooling water reservoir from both the thermostat and the pressure valve. And the cooling water which flows in from a thermostat is warmer than the cooling water which flows in from a pressure valve. Therefore, the temperature of the cooling water reservoir rises when flowing from the thermostat, and conversely, the temperature of the cooling water reservoir decreases when flowing from the pressure valve.
[0004]
[Problems to be solved by the invention]
As described above, the temperature of the cooling water in the cooling water reservoir is not constant and varies considerably. Along with this, the oil temperature of the engine oil in the oil pan also fluctuates, making it difficult for the engine to improve the predetermined performance. For example, if the oil temperature of the engine oil is too low, the viscosity of the engine oil increases and the engine efficiency decreases. On the other hand, when the oil temperature of the engine oil is too high, the lubrication performance of the engine oil is lowered or the engine oil is deteriorated.
[0005]
An object of the present invention is to provide a cooling structure for an outboard motor that can reduce fluctuations in the temperature of cooling water in a cooling water reservoir that cools an oil pan. And
[0006]
[Means for Solving the Problems]
The cooling structure of the outboard motor of the present invention includes an oil pan (51) that stores engine oil, a pump (27) that sucks cooling water outside the outboard motor, and cooling water sucked by the pump flows. A cooling water channel (91, 93, 94, 101, 103, etc.) for cooling the engine (7) with this cooling water, a thermostat (119) arranged in this cooling water channel, and an upstream of this thermostat. A pressure valve (114), and an oil pan cooling water reservoir (86) for cooling at least the oil pan; A muffler (84) disposed below the oil pan, through which combustion gas from the engine passes, and a muffler cooling water reservoir (85) for cooling the muffler; It has.
[0007]
And The cylinders (11) of the engine are arranged in a left-right direction so as to be V-shaped, and are arranged downstream of the thermostat between the cylinders arranged adjacent to each other in a V-shape. A cooling water channel (94) is arranged, When the cooling water is higher than the set temperature, the thermostat allows the cooling water to flow into the oil pan cooling water reservoir, and conversely, when the cooling water is lower than the set temperature, the flow of the cooling water is blocked.
[0008]
On the other hand, the pressure valve drains the cooling water out of the ship without passing through the oil pan cooling water reservoir when the water pressure in the cooling water channel is high, and conversely, when the water pressure in the cooling water channel is low, Shed And when the cooling water channel has a high water pressure and the cooling water is discharged from the pressure valve to the outside of the ship, at least a part of the cooling water is discharged outside the ship through the muffler cooling water reservoir. ing .
[0009]
Also, when the engine oil temperature is high, the cooling water from the pressure valve And cool both the muffler A switching valve (133) for discharging the cooling water from the pressure valve to the outside of the ship without passing through the cooling water reservoir when the oil temperature of the engine oil is low may be provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, a first embodiment of an outboard motor cooling structure according to the present invention will be described with reference to FIGS. FIG. 1 is a partially cutaway sectional view of an outboard motor according to the present invention. FIG. 2 is a plan view showing the internal structure of the outboard motor of FIG. FIG. 3 is a cross-sectional view for explaining the internal structure of the outboard motor of FIG. FIG. 4 is an explanatory diagram for explaining a throttle valve and a surge tank. FIG. 5 is a circuit diagram of the cooling water channel. FIG. 6 is an enlarged view of a main part of FIG. FIG. 7 is an explanatory diagram for explaining the apron. FIG. 8 is an enlarged view of a main part of FIG.
[0011]
First, the overall structure of the outboard motor will be described.
In FIG. 1, the outboard motor is covered with a housing including an upper cowling 1, a lower cowling 2, an upper casing 3 and a lower casing 4 in order from the upper side. A mounting bracket 6 is provided on the guide exhaust 23 and the upper casing 3 inside the lower cowling 2 via a swivel shaft 5 or the like. By fixing the mounting bracket 6 to the stern of a small boat such as a motor boat (not shown), the outboard motor is attached to the small boat so as to be rotatable in the left-right direction and the vertical direction.
[0012]
1 to 3, a V-type 6-cylinder four-cycle engine 7 is disposed inside the upper cowling 1 and the lower cowling 2. The crankshaft 8 of the engine 7 has a substantially vertical axis, and a pair of left and right cylinders 11 are arranged in a rearward manner so as to be V-shaped in the left-right direction. This pair of left and right cylinders 11 is provided in three stages in the vertical direction, and a total of six cylinders 11 are arranged. Further, six pistons 13 are connected to the crankshaft 8 via connecting rods 14, and the pistons 13 are slidably disposed inside the cylinders 11. The case 17 of the engine 7 covers the cylinder block 20 that forms the above-described six cylinders 11, the crankcase 21 that covers the crankshaft 8 side of the cylinder block 20, and the combustion chamber 11 a side of the cylinder block 20. It consists of a pair of left and right cylinder heads 22 that close. The engine case 17 is fixed to the upper surface of the upper casing 3 via a guide exhaust 23.
[0013]
The lower end of the crankshaft 8 extends from the engine case 17 and is connected to a drive shaft 26 disposed in the upper casing 3. A water pump 27 is provided in the middle of the drive shaft 26. The rotation of the drive shaft 26 is transmitted to a propeller 28 that is rotatably provided at the rear end portion of the lower casing 4 via a bevel gear (not shown).
[0014]
In addition, an intake passage 31 that supplies air to the cylinder 11 and an exhaust passage 32 that exhausts the combustion gas of the cylinder 11 are formed in the cylinder head 22 for each cylinder 11. An intake valve 35 opens and closes the port of the intake passage 31, and an exhaust valve 36 opens and closes the port of the exhaust passage 32. The intake valve 35 is driven by an intake valve camshaft 38, and the exhaust valve 36 is driven by an exhaust valve camshaft 39. The intake valve camshaft 38 and the exhaust valve camshaft 39 are provided on the right cylinder head 22 and the left cylinder head 22, respectively, and extend in the vertical direction so that one camshaft 38, 39 is provided. The three valves 35 and 36 can be controlled. The crankshaft 8 drives the camshafts 38 and 39 via a timing belt 48 and the like.
[0015]
Next, the flow of engine oil will be described.
In FIGS. 1 and 3, an oil pan 51 is suspended from the lower surface of the guide exhaust 23, and a strainer 52 is provided inside the oil pan 51. An oil pump 54 is provided at the lower end of the crankshaft 8, and when the crankshaft 8 rotates, the oil pump 54 is driven to suck up engine oil stored in the oil pan 51 through the strainer 52. The engine oil sucked up from the strainer 52 reaches the oil pump 54 through the oil passage formed in the guide exhaust 23 and the cylinder block 20, and further passes through the oil passage formed in the crankcase 21 to the filter 56. And is filtered by a filter 56. The oil that has passed through the filter 56 is supplied to the crankshaft 8 through a gallery 57 that extends in the vertical direction in the crankcase 21. And it splashes out of the crankshaft 8 from the some hole formed in the crankshaft 8, and the inside of the engine case 17 is lubricated. Then, the scattered oil and the like are collected again in the oil pan 51 through an oil passage (not shown).
[0016]
Next, the flow of air sucked and exhausted by the engine 7 will be described.
In FIGS. 1, 3, and 4, the air outside the outboard motor flows in from an air intake 61 provided on the upper side of the upper cowling 1, and an air flow formed on the upper surface of the flywheel cover 62. It passes through the path 63 and reaches the air intake pipe 66 of the engine 7. The air flowing into the air intake pipe 66 passes through the throttle valve 67, branches in the left-right direction and flows into the surge tank 69 as shown in FIG. Each of the surge tanks 69 is formed with three branch pipes 71, and the end of the branch pipe 71 is connected to the intake passage 31 via an intech manifold 73. An injector 74 is attached to the intech manifold 73.
[0017]
Fuel from a fuel tank mounted on a small vessel (not shown) is supplied to the injector 74 via a vapor separator tank 76. The timing and amount of supply of the fuel are controlled by a control unit (not shown). ) Is in control.
[0018]
The air in the intake passage 31 mixed with fuel flows into the cylinder 11 and burns when the intake valve 35 is opened, as is well known. The combustion gas is exhausted into the exhaust passage 32 when the exhaust valve 36 is opened. Three exhaust passages 32 are formed in each of the left and right cylinder heads 22, but all ends of the exhaust passage 32 are connected to an exhaust passage 79 formed in the cylinder block 20. The exhaust passage 79 is formed between the left and right cylinders 11 arranged adjacent to each other in a V shape, extends in the cylinder block 20 in the vertical direction, is closed at the upper end, and is closed at the lower end. Is formed open. Therefore, the combustion gas burned in each cylinder 11 merges in the exhaust passage 79 of the cylinder block 20, passes through the exhaust passage 81 of the guide exhaust 23 connected to the exhaust passage 79, and is connected to the exhaust passage 81. It passes through the exhaust pipe 83 and flows into the muffler 84. The combustion gas flowing into the muffler 84 is exhausted from the shaft of the propeller 28 through a passage (not shown).
[0019]
The muffler 84 is housed in the upper casing 3, but a space is formed between the muffler 84 and the upper casing 3, and this space serves as a muffler cooling water reservoir 85. In FIG. 6, the inside of the muffler 84 is divided into an exhaust passage 84a through which combustion gas passes and a drainage passage 84b through which water flows. Further, an overflow opening 84c that opens to the drainage channel 84b is formed on the side wall of the muffler 84, and water that overflows from the muffler cooling water reservoir 85 flows into the drainage channel 84b through the overflow opening 84c. Has been. The muffler 84 is formed with a cooling water inflow passage 84d.
[0020]
Further, the upper end of the muffler 84 is liquid-tightly configured with the lower surface of the oil pan 51 and the inner surface of the upper casing 3, and an oil pan cooling water reservoir 86 is formed in the space between the oil pan 51 and the upper casing 3. ing. The oil pan 51 is formed with a drainage channel 51 a communicating with the drainage channel 84 b of the muffler 84 and a cooling water inlet channel 51 b communicating with the cooling water inflow channel 84 d of the muffler 84. Further, an overflow opening 51c that opens to the drain 51a is formed on the side wall of the oil pan 51 so that water overflowing from the oil pan cooling water reservoir 86 flows into the drain 51a through the overflow opening 51c. It is configured. The oil pan 51 having such a configuration is provided on the upper portion of the upper casing 3, and the outer side of the upper portion of the upper casing 3 is covered and covered with an apron 88 illustrated in FIGS. 6 and 7.
[0021]
Next, a cooling water channel is demonstrated using FIG.2, FIG.5, FIG.6 and FIG. 5 shows the cylinder block 20 in the center, and the left and right cylinder heads 22 are shown as being removed from the cylinder block 20 and arranged on the left and right sides of the cylinder block 20. Are shown in a connected state.
[0022]
The cylinder block 20 of the engine 7 includes a cylinder cooling water passage 91 provided around the cylinder 11 for cooling the cylinder 11 and a cylinder block exhaust passage cooling for cooling the exhaust passage 79 of the cylinder block 20. A water channel 93 and a return cooling water channel 94 are provided. The cylinder cooling water passage 91 is provided in each of the left and right cylinders 11 and extends in the vertical direction along the periphery of the three cylinders 11 arranged in the vertical direction. Is cooling the three cylinders 11. The cylinder block exhaust passage cooling water passage 93 is disposed between the cylinder cooling water passage 91 and the exhaust passage 79 of the cylinder block 20. The return cooling water passage 94 is provided at the corner on the crankshaft 8 side between the pair of left and right cylinders 11 arranged in a V shape.
[0023]
On the other hand, each of the pair of left and right cylinder heads 22 is formed with a cylinder head exhaust passage cooling water passage 101 for cooling the exhaust passage 32 of the cylinder head 22 and a combustion chamber cooling water passage 103 for cooling the combustion chamber 11a. Has been. The cylinder head exhaust passage cooling water passages 101 are formed so as to extend in the vertical direction along the outer surface of the exhaust passages 32 arranged in the vertical direction. The combustion chamber cooling water channel 103 extends in the vertical direction along the periphery of the combustion chamber 11a.
[0024]
When the cylinder head 22 and the cylinder block 20 are coupled, as shown in FIGS. 2 and 5, the upper end portion of the cylinder block exhaust passage cooling water passage 93 is connected to the cylinder head exhaust passage cooling water passage 101. It communicates with the upper end of the. Further, as shown in FIGS. 5 and 8, the cylinder cooling water passage 91 and the combustion chamber cooling water passage 103 communicate with each other at both upper and lower ends and in the middle. Further, as shown in FIGS. 5 and 6, the lower end of the cylinder head exhaust passage cooling water passage 101 and the lower ends of the cylinder cooling water passage 91 and the combustion chamber cooling water passage 103 are formed in the guide exhaust 23. They are connected via a communication path 106.
[0025]
When the crankshaft 8 is rotated, the drive shaft 26 is rotated accordingly, and the water pump 27 is operated. Then, water outside the outboard motor is sucked from the water intake 108 (see FIG. 5) formed in the lower casing 4, and is supplied from the water pump 27 to the cooling water passage 93 for the cylinder block exhaust passage through the water tube 111 and the like. It flows in and cools the exhaust passage 79 of the cylinder block 20. After passing through the cylinder block exhaust passage cooling water passage 93, it flows into the cylinder head exhaust passage cooling water passage 101 and cools the exhaust passage 32 of the cylinder head 22. A pressure valve 114 is provided in a water passage extending from a lower end portion which is a terminal portion of the cylinder head exhaust passage cooling water passage 101. The pressure valve 114 is arranged between the pair of left and right cylinder heads 22 in a plan view as shown in FIG.
[0026]
When the pressure of the cooling water is higher than the predetermined pressure, the pressure valve 114 is opened, and the cooling water flows from the pressure valve 114 to the pipe 115, the cooling water inflow passage 51b of the oil pan 51, and the cooling water inflow passage of the muffler 84. It is discharged to the muffler cooling water reservoir 85 through 84d. The cooling water collected in the muffler cooling water reservoir 85 cools the muffler 84. When the cooling water accumulated in the muffler cooling water reservoir 85 overflows, the drainage (not shown) formed in the lower casing 4 passes through the overflow opening 84c and passes through the drainage channel 84b of the muffler 84 as described above. Drained from the mouth to the outside of the outboard motor.
[0027]
On the other hand, when the pressure of the cooling water is smaller than the set pressure of the pressure valve 114, the pressure valve 114 is closed, so that the cooling water passes through the communication path 106 and the cooling water passage 91 for the cylinder and the cooling for the combustion chamber. It flows into the water channel 103 and cools the cylinder 11 and the combustion chamber 11a. The cylinder cooling water channel 91 and the combustion chamber cooling water channel 103 merge at the upper end. A thermostat 119 is provided downstream of the junction. Two thermostats 119 for the right cylinder 11 and the left cylinder 11 are attached to the upper surface of the cylinder block 20. Then, the cooling water discharged from both thermostats 119 flows into a return cooling water channel 94 provided downstream of the thermostat 119. The thermostat 119 is opened when the temperature of the cooling water is equal to or higher than a predetermined temperature, that is, a set temperature of the thermostat 119, and allows the cooling water to flow into the return cooling water channel 94. If it is less, the flow is closed and the flow of the cooling water to the return cooling water channel 94 is blocked or narrowed.
[0028]
By the way, when the thermostat 119 is opened, the pressure of the cooling water is lowered and the pressure valve 114 is closed. On the other hand, when the thermostat 119 is closed, the pressure of the cooling water increases, and the pressure valve 114 is opened.
[0029]
Then, the cooling water that has flowed into the return cooling water channel 94 flows from the lower end of the return cooling water channel 94 into the oil pan cooling water reservoir 86 through the cooling water channel 121 of the guide exhaust 23 and the cooling water channel (not shown). The water accumulated in the oil pan cooling water reservoir 86 cools the oil pan 51. When the cooling water accumulated in the oil pan cooling water reservoir 86 overflows, the muffler cooling is performed from the overflow opening 51c of the oil pan 51 through the drainage channel 51a of the oil pan 51 and the drainage channel 84b of the muffler 84. Similar to the cooling water in the water reservoir 85, the water is drained from the drain port (not shown) formed in the lower casing 4 to the outside of the outboard motor.
[0030]
When the outboard motor configured in this way is driven, the temperature of the engine 7 is low at the beginning of driving, and therefore the temperature of the cooling water in the cylinder cooling water passage 91 for cooling the cylinder 11 is often low. In this case, the thermostat 119 is closed, and the cooling water pumped up by the water pump 27 passes through the cylinder block exhaust passage cooling water passage 93 and the cylinder head exhaust passage cooling water passage 101 as described above, and is pressurized. The water is discharged to the muffler cooling water reservoir 85 through the valve 114 and the pipe 115. Therefore, the cooling water cools the exhaust passage 79 of the cylinder block 20 and the exhaust passage 32 of the cylinder head 22, but the cylinder 11 and the combustion chamber 11a are hardly cooled. As a result, the exhaust gas of the engine 7 can be sufficiently cooled, and the cylinder 11 and the combustion chamber 11a are not unnecessarily cooled.
[0031]
Then, as time elapses, the temperature of the engine 7 rises, and when the temperature of the cylinder 11 rises, the thermostat 119 is opened accordingly. Then, the cooling water that has reached the vicinity of the pressure valve 114 through the cylinder block exhaust passage cooling water passage 93 and the cylinder head exhaust passage cooling water passage 101 flows into the cylinder cooling water passage 91 and the combustion chamber cooling water passage 103. Further, the cooling water existing in the cylinder cooling water passage 91 and the combustion chamber cooling water passage 103 and having a temperature equal to or higher than the thermostat set temperature is pushed out, passes through the thermostat 119, and passes through the return cooling water passage 94 to the oil pan cooling water reservoir 86. To be drained. Then, the cooling water pumped up by the water pump 27 flows into the cylinder block exhaust passage cooling water passage 93 and the cylinder head exhaust passage cooling water passage 101. The thermostat 119 is closed when new cooling water below the thermostat set temperature flows into the cylinder cooling water passage 91 and the combustion chamber cooling water passage 103. Therefore, the cooling water can cool the exhaust passage 79 of the cylinder block 20 and the exhaust passage 32 of the cylinder head 22, and can also cool the cylinder 11 and the combustion chamber 11a. As a result, the exhaust gas of the engine 7 can be sufficiently cooled, and the cylinder 11 and the combustion chamber 11a can also be cooled.
[0032]
In the state where the thermostat 119 is closed, the cooling water pumped up by the water pump 27 passes through the cylinder block exhaust passage cooling water passage 93 and the cylinder head exhaust passage cooling water passage 101 as described above. The water is discharged to the muffler cooling water reservoir 85 through 114.
[0033]
In this manner, cooling water that is equal to or higher than the set temperature of the thermostat 119, that is, warm cooling water whose temperature is controlled, flows into the oil pan cooling water reservoir 86, while the muffler cooling water reservoir 85 is discharged from the pressure valve 114. Relatively cool cooling water flows in. Therefore, even when the temperature of the engine 7 is low, for example, when the engine 7 is at a low speed, the engine oil stored in the oil pan 51 is not supercooled. Further, the muffler 84 is sufficiently cooled by relatively cool cooling water discharged from the pressure valve 114.
[0034]
In FIG. 2, reference numeral 126 denotes an alternator for power generation, reference numeral 127 denotes a belt for driving the alternator, and reference numeral 128 denotes a starter motor for starting.
[0035]
As described above, in the first embodiment of the present invention, the outer peripheral surface of the oil pan cooling water reservoir 86, that is, the upper surface of the upper casing 3, becomes relatively hot, and the calcium content in the seawater adheres and whitens. It may look bad. However, since the upper part of the upper casing 3 is covered with the apron 88 as described above, the appearance of the outboard motor itself is not deteriorated.
[0036]
Further, since the relatively cool cooling water flows into the muffler cooling water reservoir 85, the outer peripheral surface of the muffler cooling water reservoir 85 is rarely whitened. Therefore, it is possible to prevent the upper casing 3 from being whitened and the appearance of the outboard motor from being damaged.
[0037]
Further, as shown in FIG. 2, the thermostat 119 is displaced from the timing belt 48 or the like, that is, disposed on the inner side of the timing belt 48 or the like, so that interference between the thermostat 119 and the timing belt 48 is avoided. Can do. Thus, the interference between the thermostat 119 and the timing belt 48 is avoided in the lateral direction, and the height of the outboard motor can be reduced as compared with the case where the interference is avoided in the vertical direction. In addition, the lateral width of the outboard motor does not increase because it is avoided inward with respect to the timing belt 48 and the like.
[0038]
Next, a second embodiment of the outboard motor cooling structure according to the present invention will be described with reference to FIGS. FIG. 9 is an enlarged sectional view of a main part of the second embodiment. FIG. 10 is a control circuit diagram of the switching valve. FIG. 11 is an operation state diagram of the switching valve, where (a) is a diagram when the oil temperature of the engine oil is high, and (b) is a diagram when the oil temperature of the engine oil is low. In the description of the second embodiment, the same reference numerals are given to the components corresponding to the components of the first embodiment, and the detailed description thereof is omitted.
[0039]
In the second embodiment, the upper end of the muffler 84 is liquid-tight with the oil pan 51, but is not liquid-tight with the upper casing 3. Therefore, the muffler cooling water reservoir 85 and the oil pan cooling water reservoir 86 are integrated with each other, and the cooling water reservoir 131 is formed. The cooling water reservoir 131 cools the muffler 84 and the oil pan 51.
[0040]
When the pressure of the cooling water is high and the pressure valve 114 is opened, the cooling water is discharged to the pipe 115, and a switching valve 133 is provided on the downstream side of the pipe 115. The downstream of the switching valve 133 is divided into two flow paths, one of which is in communication with the drain 51 a of the oil pan 51 and the other of which is in communication with the cooling water reservoir 131. In the second embodiment, the cooling water inflow passage 51b of the oil pan 51 and the cooling water inflow passage 84d of the muffler 84 are not formed in the first embodiment.
[0041]
The switching valve 133 is controlled by the control circuit shown in FIG. 10, and the oil temperature sensor 136 (see FIGS. 9 and 10) provided in the gallery 57 is engine oil flowing through the gallery 57. The oil temperature is detected. The detection value of the oil temperature sensor 136 is output to an electronic control unit (ECU) 138 such as a microcomputer. Then, the electronic control unit 138 outputs a command rotation angle to the switching valve 133 to the servo motor 140 in response to detection by the oil temperature sensor 136. The servo motor 140 rotates the valve of the switching valve 133 in accordance with a command from the electronic control device 138 to obtain a command rotation angle. The ratio of the amount of cooling water flowing out from the switching valve 133 to the drainage channel 51a and the amount of cooling water flowing into the cooling water reservoir 131 is changed by the rotation angle of this valve. Then, as shown in FIG. 11A, the electronic control unit 138 increases the amount of cooling water flowing into the cooling water reservoir 131 when the oil temperature is high, and on the other hand, when the oil temperature is low, As shown in FIG. b), the switching valve 133 is controlled so as to increase the amount flowing into the drainage channel 51a.
[0042]
On the other hand, when the pressure of the cooling water is low, that is, when the thermostat 119 (see FIG. 6) is open, the cooling water discharged from the thermostat 119 is stored in the cooling water reservoir via the return cooling water channel 94 and the cooling water channel 121. 131.
[0043]
In the second embodiment configured as described above, when the temperature of the cooling water in the thermostat 119 is high, as described above, the thermostat 119 opens and flows into the cooling water reservoir 131 through the return cooling water channel 94 or the like. To do. On the other hand, when the temperature of the cooling water in the thermostat 119 is low, the thermostat 119 is closed and the pressure of the cooling water increases. Then, the pressure valve 114 is opened, and the cooling water flows into the pipe 115. Then, when the oil temperature of the engine oil is low, the cooling water does not pass through the cooling water reservoir 131 and is discharged out of the ship as it is. On the other hand, when the oil temperature of the engine oil is high, the cooling water flows into the cooling water reservoir 131, the temperature of the cooling water reservoir 131 is lowered, and the oil pan 51 can be sufficiently cooled. Therefore, it is possible to prevent the engine oil from being overcooled and the oil temperature of the engine oil from being excessively increased. As a result, since the oil temperature of the engine oil is stabilized, the engine 7 can exhibit the expected performance. Further, the lubrication performance of the engine oil is reduced and the engine oil is less deteriorated.
[0044]
Further, relatively warm cooling water from the thermostat 119 also flows into the cooling water reservoir 131. This cooling water cools the engine oil in the oil pan 51, and when the oil temperature of the engine oil in the oil pan 51 is too low, the engine oil in the oil pan 51 may be kept warm or warmed.
[0045]
Thus, in the second embodiment, since the oil temperature sensor 136 is provided in the gallery 57, the maintenance is easier than in the case where the oil temperature sensor 136 is provided in the oil pan 51 or the like. Further, the gallery 57 is rich in oil amount, and the oil temperature can be easily detected.
[0046]
Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be done. Examples of modifications of the present invention are illustrated below.
(1) In the embodiment, the engine 7 is a V-type 6 cylinder, but the number of cylinders, the type, and the like can be appropriately changed.
[0047]
(2) If the oil temperature sensor 136 can directly or indirectly detect the oil temperature of the engine oil, the installation position can be changed as appropriate. For example, the oil pan 51 can be installed. It can also be installed in an oil passage or the like through which engine oil other than the gallery 57 flows.
(3) In the embodiment, the mounting positions of the pressure valve 114 and the thermostat 119 can be changed as appropriate.
[0048]
(4) In the second embodiment, the switching valve 133 controls the flow rate of the cooling water flowing in the drain 51a or the cooling water reservoir 131 in an analog manner, but it can also be controlled on and off. .
[0049]
【The invention's effect】
According to the present invention, when the cooling water is higher than the set temperature of the thermostat, the cooling water flows from the thermostat to the oil pan cooling water reservoir, and the relatively cold cooling water from the pressure valve passes through the oil pan cooling water reservoir. It is not drained out of the ship. Therefore, cooling water whose temperature is controlled by a thermostat flows into the oil pan cooling water reservoir. As a result, the oil pan can be prevented from being overcooled, and the engine can exhibit the expected performance.
[0050]
In addition, a muffler cooling water reservoir is provided separately from the oil pan cooling water reservoir, and cooling water from a pressure valve may flow into the muffler cooling water. Since the cooling water from the pressure valve has a lower temperature than the cooling water from the thermostat, the muffler can be sufficiently cooled. As a result, the heat of the muffler can be prevented from affecting other members.
[0051]
And since the cooling water channel downstream from the thermostat is arranged between the left and right cylinders, one cooling water channel can be used in common for the left and right cylinders. Therefore, the outboard motor can be configured more compactly than in the case where the cooling water channel is arranged for each of the left and right cylinders. Further, a narrow space between the cylinders can be effectively used.
[0052]
Furthermore, when the engine oil temperature is high, the cooling water from the pressure valve , Cooling oil pan and muffler There is a case in which a switching valve is provided for discharging the cooling water from the pressure valve to the outside of the ship without passing through the cooling water reservoir when the oil temperature of the engine oil is low. In this case, While cooling the muffler, The oil temperature of engine oil can be stabilized. As a result, the engine can exhibit the desired performance.
[Brief description of the drawings]
FIG. 1 is a partially cutaway sectional view of an outboard motor according to the present invention.
FIG. 2 is a plan view showing an internal structure of the outboard motor of FIG.
FIG. 3 is a cross-sectional view for explaining the internal structure of the outboard motor of FIG.
FIG. 4 is an explanatory diagram for explaining a throttle valve and a surge tank.
FIG. 5 is a circuit diagram of a cooling water channel.
FIG. 6 is an enlarged view of a main part of FIG.
FIG. 7 is an explanatory diagram for explaining an apron.
FIG. 8 is an enlarged view of a main part of FIG.
FIG. 9 is an enlarged cross-sectional view of a main part of a second embodiment.
FIG. 10 is a control circuit diagram of the switching valve.
FIG. 11 is an operational state diagram of the switching valve, where (a) is a diagram when the oil temperature of the engine oil is high, and (b) is a diagram when the oil temperature of the engine oil is low.
[Explanation of symbols]
7 engine
11 cylinders
27 Water pump
51 Oil pan
84 Muffler
85 Muffler cooling water reservoir
86 Reservoir for oil pan cooling
91 Cylinder cooling water channel
93 Cooling water passage for cylinder block exhaust passage
94 Cooling channel for return
101 Cylinder head exhaust passage cooling water channel
103 Cooling water channel for combustion chamber
114 Pressure valve
119 Thermostat
133 Switching valve

Claims (2)

An oil pan that holds engine oil,
A pump for sucking cooling water outside the outboard motor,
As the cooling water sucked in by this pump flows, a cooling water channel for cooling the engine with this cooling water,
A thermostat arranged in this cooling channel,
A pressure valve arranged upstream of the thermostat;
An oil pan cooling water reservoir for cooling at least the oil pan ;
A muffler that is disposed below the oil pan and through which combustion gas from the engine passes,
It has a muffler cooling water reservoir that cools this muffler ,
The cylinders of the engine are configured to be V-shaped by being distributed in the left-right direction,
A cooling water channel downstream from the thermostat is arranged between the cylinders arranged adjacent to each other in the left and right sides in a V shape,
When the cooling water is higher than the set temperature, the thermostat causes the cooling water to flow into the oil pan cooling water reservoir, and conversely, when the cooling water is lower than the set temperature, the flow of the cooling water is blocked.
On the other hand, the pressure valve drains the cooling water out of the ship without passing through the oil pan cooling water reservoir when the water pressure in the cooling water channel is high, and conversely, when the water pressure in the cooling water channel is low, It is poured into,
In addition, when the water pressure in the cooling water channel is high and the cooling water is discharged from the pressure valve to the outside of the ship, at least a part of the cooling water is discharged outside the ship through the muffler cooling water reservoir. A cooling structure for an outboard motor. An oil pan that holds engine oil,
A muffler through which combustion gas from the engine passes,
A pump for sucking cooling water outside the outboard motor,
As the cooling water sucked in by this pump flows, a cooling water channel for cooling the engine with this cooling water,
A thermostat arranged in this cooling channel,
A pressure valve arranged upstream of the thermostat;
A reservoir of cold却用water cool both the oil pan and the muffler,
When the engine oil temperature is high, the cooling water from the pressure valve flows into the cooling reservoir. Conversely, when the engine oil temperature is low, the cooling water from the pressure valve does not pass through the cooling reservoir. A switching valve that discharges to the outside,
When the cooling water is higher than the set temperature, the thermostat causes the cooling water to flow into the cooling water reservoir, and conversely, when the cooling water is lower than the set temperature, the flow of the cooling water is blocked.
On the other hand, the pressure valve drains the cooling water to the switching valve when the water pressure of the cooling water channel is high, and conversely, when the water pressure of the cooling water channel is low, the cooling water flows to the thermostat. Outboard motor cooling structure.

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