JPS62116373A - Engine cooling device for motorcycle, etc. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in engine cooling devices for motorcycles and the like.

(Prior Art) When a water-cooled engine is mounted on a motorcycle such as a scooter, a radiator for cooling the engine is essential.

Incidentally, in a radiator, heat exchange occurs between the cooling water flowing through the radiator and the cold air guided therethrough, but instead of introducing the cold air into the radiator by natural ventilation, it is forced by a cooling fan. The present applicant has previously proposed to do so (Japanese Utility Model Application Publication No. 59-45176). An example of the structure is shown in FIG. 3, and a cooling fan 019 is attached to the end of the output shaft 09 of the engine 01.
A radiator 028 is interposed between the cooling fan 019 and the rear cover 02. And fan cover 02
An air exhaust duct 025 leads upward from a part of the air outlet 4, and the end of the air exhaust duct 025 opens rearward.

As a result, the cooling fan 019 is driven by the engine 01.
When the cooling fan 019 is driven to rotate, the cooling fan 019 sucks outside air into the rear cover 02 through a looper 02a provided on the rear cover 02. This sucked outside air passes through the radiator 028 and cools the cooling water flowing inside the radiator 028, and then passes through the exhaust duct 025 and is discharged rearward from the open end of the duct 025 (see arrows in the figure).

(Problem to be Solved by the Invention) However, in the conventional cooling device described above, the outside air is passed through the radiator 028 only once, that is, it is used for cooling only once, and is not used again, and is directly passed through the air guide ducts 1 to 1.
025 to the outside, there was a problem in that the cooling efficiency and cooling capacity of the cooling device were poor.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an engine cooling device for a motorcycle or the like that can improve cooling efficiency and cooling capacity.

(Means for Solving the Problems) In order to achieve the above object, the present invention forms an outside air flow passage with a fan cover having an outside air inlet that covers the cooling fan and a shroud that covers the engine cylinder. The discharge port of the outside air flow passage was disposed on the downstream side of the engine cylinder, and a radiator was provided at the discharge port.

(Function) The outside air sucked into the fan cover by the cooling fan first cools the cooling water in the water jacket formed on the engine cylinder peripheral wall, and then flows out from the outlet of the outside air flow passage. The cooling water is cooled by the radiator. In this way, since the outside air cools the cooling water in two stages while passing through the outside air flow path, the cooling efficiency and cooling capacity of the engine cooling system are improved.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an internal combustion engine equipped with a cooling device according to the present invention, and FIG. 2 is an exploded perspective view of the same internal combustion engine.

The illustrated internal combustion engine 1 is a water-cooled two-stroke engine, in which a piston 3 is fitted in a cylinder 2 so as to be vertically slidable. connected. Furthermore, cylinder 2
There is a water jacket 6 through which the cooling water should pass.
are formed, and cooling fins 2a... are formed on the outer periphery of the cylinder 2. Further, a spark plug 7 is screwed into the center of the top of the cylinder 2.

On the other hand, a crankshaft 9 is inserted through the crankcase 8 located below the cylinder 2, and the crankshaft 9 is rotatably supported by ball bearings to and 1o. In addition, in FIG. 1, 11.11 is a shaft seal. Further, the lower end of the connecting rod 4 is connected to the crankshaft 9 by a crank pin 12.

In FIG. 1, 13 is an intake port, and 14 is a scavenging port. An intake pipe 15 is connected to the intake port 13, and a reed valve 16 is provided at the end of the intake pipe 15.

By the way, a rotating drum 17 that constitutes a part of the generator is fixed to one end of the crankshaft 9 with a nut 18, and a cooling fan 19 is fastened to the outer surface of the rotating drum 17 with bolts 20 and 20. has been done. In addition, the rotating drum 17
A rotor 21 is fixed to the inner peripheral wall of the crankcase 8, and a stator 22 is fixed to the end of the crankcase 8 with bolts 23 inside the rotor 21.

The cooling fan 19 is covered by a fan cover 24, which is fixed to the side of the engine 1 with bolts 25, 25.

A suction port 24a is opened at a position of the fan cover 24 facing the cooling fan 19, and a grille 26 is provided in the suction port 24a to prevent foreign matter from being sucked in.

Further, the circumference of the cylinder 2 is covered by a shroud 27 whose negative side is open, but the open part of the shroud 27 is closed by the fan cover 24. Thus, the space surrounded by the shroud 27 and the fan cover 24 is configured as an outside airflow passage 28.

By the way, an outside air flow passage 2 is provided on the upper surface of the shroud 27.
Eight discharge ports 27a are formed, and a ring-shaped radiator 29 is provided in the discharge ports 27a. That is, brackets 3o, 3o bent in an L-shape are welded to the outer peripheral wall of this radiator 29, and the radiator 29 has bolts 31, 31 inserted into the brackets 3o, 30, and nuts screwed into the bolts 31, 31. 32, ; 32 are attached to the periphery of the discharge hole 27a of the shroud 27 with elastic packings 33 and 33 sandwiched between them. Note that the radiator 29 includes ring-shaped fin tubes 29a, 2 having a flat rectangular cross section.
It is constructed by concentrically arranging 9ar.

The radiator 29 and the water jacket 6 formed inside the cylinder 2 communicate with each other through pipes 34 and 35, and a water inlet 36 is provided in the middle of the pipe 35.
and a water pump 37 are interposed. Note that the water inlet 36 is provided at the top of the piping, but this means that once the water inlet 36 is filled with cooling water, the water jacket 6, radiator 29, pipes 34, 35, etc. are filled with cooling water. This is because it can be confirmed.

As shown in FIG. 2, an exhaust pipe 38 leads out from the engine cylinder 2, and an exhaust muffler 39 is connected to the end of the pipe extending toward the rear of the motorcycle. Also, the second
In the figure, 40 is the rear axle of the motorcycle.

Next, the operation of this engine cooling system will be explained.

When the internal combustion engine 1 is driven and its crankshaft 9 rotates, the cooling fan 19 directly connected to the end of the internal combustion engine 1 is also driven to rotate. As the cooling fan 19 rotates, outside air is sucked into the fan cover 24 through the suction port 24a provided in the fan cover 24. This sucked outside air flows through the outside air flow path 28 surrounded by the fan cover 28 and the shroud 27, but in this flow process, it first passes through the cooling fins 2a formed on the outer periphery of the cylinder 2. to cool the cooling water in the water jacket 6. The next time the cooling water flows out from the discharge port 27a, it passes through the radiator 29 provided here, and the cooling water passing through the radiator 29 is cooled again.

As described above, since the outside air cools the cooling water in two stages in the process of passing through the outside air flow passage 28, the cooling efficiency and cooling capacity of the engine cooling system are increased, and the radiator 29 is made smaller by the increased cooling capacity. can be converted into

(Effects of the Invention) As is clear from the above description, according to the present invention, an outside air flow passage is formed by a fan cover having an outside air inlet that covers the cooling fan and a shroud that covers the engine cylinder, and Since the outlet of the passage is placed on the downstream side of the engine cylinder and a radiator is installed at the outlet, the outside air sucked into the fan cover by the cooling fan is first cooled in the water jacket formed on the circumferential wall of the engine cylinder. The water is cooled, and then when it flows out from the outlet of the outside air flow passage, the cooling water is cooled by the radiator installed here, so in the end, the outside air cools the cooling water in two stages as it flows through the outside air flow passage. As a result, the cooling efficiency and cooling capacity of the engine cooling system are improved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an internal combustion engine equipped with a cooling device according to the present invention, FIG. 2 is an exploded perspective view of the internal combustion engine, and FIG.
The figure is a partially cutaway front view of an internal combustion engine equipped with a conventional cooling device. 1... Internal combustion engine, 2... Cylinder, 2a...
Cooling fin, 6...Water jacket, 19...
・Cooling fan, 24...Fan cover, 24a...
Suction port, 27...shroud, 27a...discharge port,
28...Outside airflow passage, 29...Radiator, 34.
35...pipe, 37...water pump.

Claims (1)

[Claims] 1. An engine cooling system for a motorcycle or other vehicle equipped with a water-cooled engine, in which an outside air flow path is formed by a fan cover with an outside air inlet that covers the cooling fan and a shroud that covers the engine cylinder. An engine cooling device for a motorcycle or the like, characterized in that a discharge port of a flow passage is disposed on the downstream side of an engine cylinder, and a radiator is provided at the discharge port.