JP3139177B2 - Outboard motor intake cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air cooling system for an outboard motor, and more particularly to a simple structure for increasing the cost of the intake air near the fuel injection valve of an outboard motor equipped with a four-cycle engine. The present invention relates to an outboard motor intake air cooling device that can be appropriately adjusted without inviting.

[0002]

2. Description of the Related Art In an outboard motor equipped with a four-cycle engine, the temperature of the intake air must be reduced because the temperature of the cylinder block becomes relatively high. On the other hand, the higher the temperature, the better the vaporization of the fuel. Therefore, it is necessary to consider the temperature of the intake air from the viewpoint of combustion stability.

Therefore, as disclosed in Japanese Utility Model Application Laid-Open No. 3-68521, an intake cooling water passage is provided on the outer periphery of each branch pipe of an intake manifold communicating between a supercharger and a cylinder head to adjust the temperature of intake air. There is something. Also, Japanese Patent Application Laid-Open No. 4-81
As disclosed in Japanese Patent No. 388, a heat exchange chamber through which exhaust gas flows is provided on the outer periphery of each branch pipe of an intake manifold located downstream of a vaporizer to adjust the temperature of intake air.

[0004]

By the way, in an engine having a fuel injection valve, unlike an engine having a carburetor, since there is no heat of vaporization by fuel in each branch pipe of the intake manifold, a high load is required. Sometimes it is necessary to sufficiently lower the intake air temperature.

However, in each of the above publications, a cooling water passage and an exhaust passage are formed on the outer periphery of each branch pipe of the intake manifold in order to adjust the temperature of the intake air.
For this reason, since each branch pipe must be formed in a double pipe structure, the mold structure is complicated, and there is a disadvantage that the cost increases.

Further, in a four-cycle engine having a fuel injection valve in each branch pipe of the intake manifold, the fuel injection valve is provided at a position close to the cylinder head of each branch pipe. There is a problem that the distance to the intake valve is short. In order to atomize the fuel over such a short distance, even if a cooling water passage or an exhaust passage is formed on the outer periphery of each branch pipe of the intake manifold, as disclosed in each of the above-mentioned publications, the vicinity of the fuel injection valve can be increased. There is a disadvantage that it is difficult to adjust the temperature of the intake air.

[0007]

SUMMARY OF THE INVENTION Accordingly, in order to eliminate the above-mentioned disadvantages, the present invention provides a crankcase, a cylinder block, and a cylinder in an engine cover and an undercover of an outboard motor in order from front to rear in the traveling direction. A block-side water formed around a cylinder of the cylinder block driven by the crankshaft, with an engine mounted thereon, the head being disposed and the crankshaft being directed substantially vertically in the cylinder block and supported by a crankcase. The suction of the jacket and the cylinder head
A water pump that supplies cooling water for the engine is provided in the head side water jacket formed around the exhaust port,
The engine is provided with an intake manifold including a surge tank and a plurality of branch pipes branched from the surge tank and connected to each intake port of the cylinder head, on one side in a direction intersecting with the traveling direction of the outboard motor, In an outboard motor equipped with a four-cycle engine provided with a fuel injection valve in each branch pipe of the intake manifold, the fuel injection valve is mounted on a head-side mounting portion of the cylinder head on a downstream side of each branch pipe. A water jacket for intake is formed by mounting one or both of the manifold-side mounting portion between the branch intake passages of the branch pipes and the head-side mounting portion between the intake ports of the cylinder head. Formed, and flowing the intake water jacket to at least the intake water jacket located at the uppermost position of each of the intake water jackets. An intake cooling water thermostat for controlling the temperature of the intake cooling water to be provided, wherein the water pump includes an engine cooling water passage flowing through the block-side water jacket and the head-side water jacket, and the intake water jacket. It is characterized in that cooling water is supplied in parallel to a flow path of the cooling water for intake air.

[0008]

According to the structure of the present invention, the fuel injection valve is mounted on the manifold side mounting portion adjacent to the cylinder head on the downstream side of each branch pipe, and the manifold side mounting portion between the branch intake passages of each branch pipe and the cylinder head are mounted. By depressing one or both of the head-side mounting portion between the respective intake ports and forming the intake water jacket, the mold structure of the intake manifold does not become complicated. In addition, an intake cooling water thermostat that controls the temperature of the intake cooling water flowing through the intake water jacket is provided at least in the intake water jacket located at the uppermost position of each intake water jacket, and the engine is cooled by a water pump. By supplying cooling water in parallel to the water path and the intake cooling water path, the temperature of the intake cooling water that regulates the intake air temperature is independent of the engine cooling water that cools the engine. Can be managed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 9 show an embodiment of the present invention. 8 and 9, reference numeral 2 denotes an outboard motor. The outboard motor 2 is covered with an engine cover 4, an under cover 6, a drive shaft housing 8, and a gear case 10, and is mounted on a hull (not shown) by a mounting unit 12 mounted in front of the drive shaft housing 8 in the traveling direction. Can be

As shown in FIGS. 6 and 7, the outboard motor 2 has an engine cover 4 and an under cover 6 on which a four-cycle engine 14 is mounted. The engine 14 sequentially moves from the front to the rear in the traveling direction of the outboard motor 2,
4, a cylinder block 20, and a cylinder head 32 are arranged. The outboard motor 2 drives the drive shaft 16 by the engine 14, converts the rotation direction by a gear (not shown), and drives the propeller 18 directed rearward in the traveling direction.

As shown in FIGS. 5 and 6, the engine 14 is supported by a crankcase 24 with a crankshaft 22 directed substantially vertically in a cylinder block 20. In the cylinder block 20, a plurality of, in this embodiment, four cylinders 26 whose cylinder axes are oriented in a substantially horizontal direction are disposed in a substantially vertical direction.
Built-in. The pistons 28 are connected to the crankshaft 22 through connecting rods 30, respectively.

A cylinder head 32 is mounted on the cylinder block 20, and a head cover 34 is attached to the cylinder head 32. The cylinder head 32 is provided with an intake port 36 and an exhaust port 38 communicating with each cylinder 26. Intake port 36 and exhaust port 3
8, an intake valve 40 and an exhaust valve 42 are provided.

As shown in FIG. 1, the intake valve 40 and the exhaust valve 42 include an intake rocker arm 44 and an exhaust rocker arm 46.
Is driven to open and close. The intake rocker arm 44 and the exhaust rocker arm 46 are supported by an intake rocker shaft 48 and an exhaust rocker shaft 50, and are swung by an intake cam 54 and an exhaust cam 56 provided on a cam shaft 52.

As shown in FIGS. 5 and 7, the engine 14 is provided with an intake manifold 58 located on one side in a direction intersecting the traveling direction of the outboard motor 2. The intake manifold 58 includes a surge tank 60 serving as a collecting portion, and a plurality of branch pipes 62 branched from the surge tank 60 and extending in the direction of the cylinder head 32, and has a tank intake passage 64 and a branch intake passage 66. ing. Each branch pipe 62
The downstream side is connected by a manifold-side mounting portion 68. The manifold side mounting portion 68 is mounted on the head side mounting portion 70 of the cylinder head 32, and communicates each branch intake passage 66 with each intake port 36.

The throttle body 7 is provided on the surge tank 60 on the upstream side of the intake manifold 58 via a spacer 72.
4 is attached, and a throttle guide 76 is attached upstream of the throttle body 74. A net 78 is attached to the upstream end of the throttle guide 76.
The guide intake passage 80 of the throttle guide 76, the body intake passage 82 of the throttle body 74, and the spacer intake passage 84 of the spacer 72 are sequentially communicated with each other and communicate with the tank intake passage 64. A throttle valve 84 is provided in the body intake passage 82.

In FIG. 5, reference numeral 86 denotes a spark plug, and reference numeral 88 denotes a branch exhaust passage communicating with each exhaust port 38. The branch exhaust passage 88 communicates with the collective exhaust passage 90 and is discharged by an exhaust pipe (not shown).

Each of the branch pipes 6 is provided in the intake manifold 58.
2 is provided with a fuel injection valve 92. The fuel injection valve 92
It is attached to the manifold side attachment portion 68 at a position close to the cylinder head 32, and injects fuel into the intake port 36. Reference numeral 93 denotes an injection valve mounting portion, and reference numeral 94 denotes a fuel distribution pipe.

As shown in FIG. 6, the engine 14
A water pump 96 driven by the drive shaft 16 is provided. The cooling water pumped up by the water pump 96 and supplied by the cooling water pipe 98 is shown in FIG.
As shown in FIGS. 2 and 4 to 6, the air flows from the block-side water jacket 100 of the cylinder block 20 to the head-side water jacket 102 of the cylinder head 32, and is discharged after cooling the engine 14. Reference numeral 104
Is an engine cooling water thermostat for controlling the temperature of the engine cooling water.

The engine 14 is provided with the components shown in FIGS.
As shown in FIG. 7, a spacer water jacket 106 is provided on the spacer 72, and a branch pipe water jacket 108 is provided in the middle of each branch pipe 62 of the intake manifold 58.
Is provided. The water jacket 108 for the branch pipe is
It is partitioned by a water jacket cover 109 for a branch pipe. Water jacket 10 for the spacer
The cooling water for intake, which is different from the cooling water for engine, flows through the water jacket 6 and the branch pipe water jacket 108.

As described above, the outboard motor 2 in which the four-cycle engine 14 having the fuel injection valve 92 is mounted on each branch pipe 62 of the intake manifold 58 is provided with the intake air cooling device. As shown in FIGS. 1, 5, and 7, this intake air cooling device includes an intake water heater for adjusting intake air temperature to a manifold-side mounting portion 68 of an intake manifold 58 mounted on a head-side mounting portion 70 of a cylinder head 32. Jacket 1
10 is provided as recessed.

The water jacket 110 for intake is shown in FIG.
As shown in the figure, the manifold side mounting portion 68 is provided between the branch intake passages 66 of the respective branch pipes 62 so as to be depressed. In this embodiment, as shown in FIG. 1 and FIG. 5, the head is attached to the head-side mounting portion 70 of the cylinder head 32 so as to face the intake water jacket 110 provided in the manifold-side mounting portion 68. The side intake water jacket 112 is provided in a recessed manner. The head-side intake water jacket portion 112 is located between the intake ports 36 of the cylinder head, and is provided in the head-side mounting portion 70 so as to be depressed.

The intake water jackets 110 provided between the branch intake passages 66 of the branch pipes 62 and recessed in the manifold-side mounting portion 68 are communicated with communication pipes (not shown). ing. In FIG. 7, the intake water jacket 11 on the most upstream side located at the lowermost position.
0 is the water jacket 108 for the branch pipe.
Is communicated to.

Further, the intake air cooling device is provided with an intake air cooling water thermostat 114 for controlling the temperature of the intake air cooling water flowing through the intake water jacket 110. The cooling water thermostat 114 for intake is provided on the outlet side of the water jacket 110 for intake located at the uppermost position in FIG. The intake cooling water thermostat 114 is opened and closed at a temperature different from the temperature managed by the engine cooling water thermostat 104, and appropriately manages the temperature of the intake cooling water.

Next, the operation will be described.

When the engine 14 of the outboard motor 2 is operating, the water pump 96 is driven by the drive shaft 16, the cooling water is pumped up by the water pump 96, and is supplied by the cooling water pipe 98. The cooling water sent is
As shown in FIG. 2, the coolant flows from the block-side water jacket 100 of the cylinder block 20 to the head-side water jacket 102 of the cylinder head 32, cools the engine 14, and is discharged from the engine cooling water thermostat 104. The temperature of the engine coolant is controlled by the engine coolant thermostat 104.

As shown in FIG. 2, the cooling water pumped up by the water pump 96 and supplied by the cooling water pipe 98 is provided separately from the engine cooling water as intake cooling water. It flows through the spacer water jacket 106 provided on the spacer 72 and flows through the branch pipe water jacket 108 provided in the middle of each branch pipe 62 of the intake manifold 58. Therefore, the water pump 96 supplies the cooling water in parallel to the path of the engine cooling water flowing through the block side water jacket 100 and the head side water jacket 102 and the path of the intake cooling water flowing through the intake water jacket 110. Send.

The intake cooling water that has flowed through the branch pipe water jacket 108 is directed upward from the most upstream intake water jacket 110 located at the lowest position in FIG. 7, the air flows into the intake water jacket 110 on the most downstream side located at the uppermost position, and the intake thermostat 114
Is discharged from

Each of these intake water jackets 110
The temperature of the intake cooling water flowing through the intake water jacket 110 is controlled by an intake cooling water thermostat 114 provided on the outlet side of the intake water jacket 110 located at the uppermost position. The intake cooling water thermostat 114 is opened and closed at a temperature different from the temperature managed by the engine cooling water thermostat 108 to manage the temperature of the intake cooling water.

Thus, the temperature of the intake air near the fuel injection valve 92 flowing from the branch intake pipe 62 to the intake port 36 can be adjusted by the intake cooling water flowing through the intake water jacket 110. Therefore, it is possible to improve the flammability and the charging efficiency.

As described above, in the intake air cooling system for the outboard motor 2, the fuel injection valve 92 is mounted on the manifold-side mounting portion 68 adjacent to the cylinder head 32 on the downstream side of each branch pipe 62. One or both of the manifold-side attachment portion 68 between the branch intake passages 66 and the head-side attachment portion 70 between the intake ports 36 of the cylinder head 32, in this embodiment, both are recessed to form the intake water jacket 110 and the head. By forming the water jacket 112 for the side intake, the mold structure of the intake manifold 58 does not become complicated. The intake air cooling device of the outboard motor 2 is opened and closed by the intake water jacket 110 located at the uppermost position of the intake water jacket 110 at a temperature different from the temperature managed by the engine cooling water thermostat 108. Cooling water thermostat 114 for controlling the temperature of the intake cooling water flowing through the water jacket 110 is provided, and the cooling water is sent by the water pump 96 to the engine cooling water path and the intake cooling water path in parallel. By supplying the cooling water, the temperature of the intake cooling water for adjusting the intake air temperature can be managed independently of the engine cooling water for cooling the engine 14.

Therefore, the temperature of the intake air near the fuel injection valve 92 of the outboard motor 2 having the four-cycle engine 14 is
With a simple structure, appropriate adjustment can be performed without increasing the cost. Thereby, the stability of combustion at low speed can be ensured, and the charging efficiency of intake air at high speed can be improved.

[0033]

As described above in detail, according to the present invention, the structure of the intake manifold is not complicated, and the temperature of the intake air is adjusted with respect to the engine cooling water for cooling the engine. The temperature of the cooling water for intake can be managed independently.

Therefore, the temperature of the intake air in the vicinity of the fuel injection valve of the outboard motor equipped with the four-cycle engine can be appropriately adjusted without increasing the cost by a simple structure. Thereby, the stability of combustion at low speed can be ensured, and the charging efficiency of intake air at high speed can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of the engine of an outboard motor according to an embodiment of the present invention, taken along line II of FIG.

FIG. 2 is an explanatory diagram of a flow of cooling water of an engine.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 5;

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 6;

FIG. 5 is an enlarged sectional view taken along line VV in FIG. 6;

FIG. 6 is an enlarged sectional view taken along line VI-VI of FIG. 9;

FIG. 7 is a side view of an engine mounted on the outboard motor.

FIG. 8 is a side view of the outboard motor.

FIG. 9 is a rear view of the outboard motor.

[Explanation of symbols]

 2 Outboard motor 14 Engine 20 Cylinder block 32 Cylinder head 36 Intake port 38 Exhaust port 58 Intake manifold 60 Surge tank 62 Branch pipe 68 Manifold side mounting part 70 Head side mounting part 92 Fuel injection valve 96 Water pump 98 Cooling water pipe 100 Block side Water jacket 102 Head side water jacket 104 Engine cooling water thermostat 106 Spacer water jacket 108 Branch pipe water jacket 110 Intake water jacket 112 Head side intake water jacket part 114 Intake cooling water thermostat

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuyuki Shomura 300, Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. (72) Inventor Hidehiko Yoshioka 300, Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. (72 ) Inventor Jiro Saiga 300 Suzuki Co., Ltd., Takatsuka-cho, Hamamatsu-shi, Shizuoka Prefecture (56) References JP-A-3-237238 (JP, A) Japanese Utility Model 58-102725 (JP, U) Japanese Utility Model 64 4851 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01P 3/02 F01P 3/20 F02B 29/04 B63H 21/26

Claims (2)

(57) [Claims] 1. An engine cover and an undercover for an outboard motor.
In the traveling direction.
Arrange the base, cylinder block and cylinder head
With the crankshaft almost perpendicular to the cylinder block
Engine which is supported by a crankcase
And the cylinder is driven by the crankshaft.
The block side wall formed around the cylinder of the double lock
Around the intake and exhaust ports of the cylinder jacket and the cylinder head
For the engine on the water jacket on the head side formed in the enclosure
A water pump for supplying cooling water, wherein the engine
On one side in the direction intersecting the direction of travel of the outboard motor
Branch from the surge tank and the cylinder head.
Of multiple branch pipes communicating with each intake port of
The air manifold is provided, in the outboard motor equipped with the four-cycle engine having a fuel injection valve to each branch pipe of the intake manifold, the fuel injection valves, each mounted on the head side mounting portion of the cylinder head Attached to the manifold-side mounting section on the downstream side of the branch pipe, the branch intake of each branch pipe
The manifold side mounting part between the passages and each of the cylinder heads
One or both of the head side mounting part between the intake ports
Depress to form a water jacket for intake, at least
Is also located at the top of each water jacket for intake.
Water jacket for the intake to care for the water jacket
The intake cooling water thermostats for managing the temperature of the intake air cooling water you circulating provided, the water pump, the blanking
Lock side water jacket and head side water jacket
A path for cooling water for the engine flowing through the
To the cooling water path for intake air flowing through the water jacket
An intake cooling device for an outboard motor, which supplies cooling water in parallel . 2. The cooling water thermostat for intake air according to claim 1 ,
Block water jacket and head water jacket
Control the temperature of engine coolant flowing through the racket
A temperature different from the control temperature of the engine cooling water thermostat
Open / close operation depending on the degree, the water jacket for intake
Control the temperature of the cooling water for intake air flowing through
The outboard motor intake cooling device according to claim 1.