JPS6128012Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a carburetor cooling device for a small forced air-cooled engine mounted on a scooter or the like.

In the case of a scooter, the engine is mounted on the part of the body covered by the frame cover under the seat, and the frame cover is provided with louvers, but it is difficult for the vehicle to be exposed to the wind when driving. The engine is cooled by forced air cooling.

However, while the vehicle is running, wind enters the frame cover and the ambient temperature near the engine decreases, but when the vehicle is stopped and idling, the ambient temperature increases and the gasoline temperature in the carburetor increases. This may cause the engine to stop.

This invention is an improvement on this in view of the above points, and an embodiment of the invention shown in the drawings will be described below.

A cooling fan 2 is connected to one end of the crankshaft 1 of the engine, and rotates together with the crankshaft 1 to blow air.

The cooling fan 2, cylinder 3, and cylinder head 4 are covered with a cover 5, and are of a forced cooling type in which air generated by the cooling fan 2 is applied to the cylinder 3 and cylinder head 4 to cool them.

However, in the present invention, the cover 5 includes:
A diversion port 7 facing the vaporizer 6 is provided, and a butterfly-shaped on-off valve 8 is rotatably mounted within the diversion port 7. This on-off valve 8 is connected to the operating piece 1 by a wire 9.
0, and this actuating piece 10 is slidably inserted into the case 11. A thermowax 12 is injected into one side of the case 11, and when it expands due to a rise in temperature, the actuating piece 1
0 is slid against springs 13 and 14 to close the on-off valve 8. The thermowax 12 portion is connected to the cylinder 3 via a heat pipe 15.

Next, the operation of the above embodiment will be explained.

During operation of the engine, the cooling fan 2 rotates together with the crankshaft 1 to blow air to cool the cylinder 3 and cylinder head 4. When the engine is running at low speeds and not producing high output, the temperature of the cylinder 3 is low, the thermowax 12 is contracted, the on-off valve 8 is open, and air is also blown from the diversion port 7.
It is blown into the vaporizer 6 and cooled. When the vehicle is stopped or traveling at low speed, it is difficult for the vehicle to be exposed to wind, and the ambient temperature near the engine becomes high.
To prevent vapor lock and engine stop. While the vehicle is running at high speed, the engine rotates at high speeds and generates high output, causing the temperature of the cylinder 3 to rise. Then, the thermowax 12 expands and pushes the actuating piece 10, the on-off valve 8 closes, and the cylinder 3 and cylinder head 4 are cooled by a sufficient amount of cooling air. At this time, the running wind enters the vicinity of the engine and the ambient temperature drops, so even if the carburetor 6 is not cooled by the cooling fan 2, vapor lock will not occur.

As explained above, this invention is a device in which a cooling fan is connected to the end of the crankshaft and rotated, and the cooling fan, cylinder, and cylinder head are covered with a cover to cool the cylinder and the cylinder head. A diversion port toward the vaporizer is provided at the diversion port, and an on-off valve is provided at the diversion port, and an actuating piece that is sensitive to the cylinder temperature is connected to the on-off valve, so that the on-off valve closes when the cylinder temperature becomes high. Therefore, when the temperature of a high-output cylinder is high, the diversion port closes and the cylinder and cylinder head can be cooled with sufficient cooling air, preventing insufficient cooling. Also, at low speeds, the ambient temperature near the engine becomes high, but since the on-off valve at the diversion port opens, the carburetor is cooled by the ventilation from the diversion port, which prevents the engine from stopping due to paper lock. is obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a side view with the cover cut away, and FIG. 2 being an enlarged longitudinal sectional side view of the main parts. 1...Crankshaft, 2...Cooling fan, 3...
Cylinder, 4...Cylinder head, 5...Cover, 6...Carburizer, 7...Diversion port, 8...Opening/closing valve, 10...Operating piece.

Claims (1)

[Scope of utility model registration request] A cooling fan is connected to the end of the crankshaft and rotated, and the cooling fan, cylinder, and cylinder head are covered with a cover to cool the cylinder and cylinder head, and the cover is provided with a diversion port toward the carburetor. , a small forced air-cooled engine characterized in that an on-off valve is provided at the branch port, an operating piece sensitive to cylinder temperature is connected to the on-off valve, and the on-off valve closes when the cylinder temperature becomes high. Vaporizer cooling device.