THE IMPORTANCE OF HEAT DISSIPATION FOR THE CORRECT OPERATION OF THE COOLING SYSTEM
July 7, 2021
The viscous clutch is the mechanism in charge of the power transmission between the vehicle engine and the fan of the cooling system. In most modern clutch designs, which are electronically controlled, apart from transmitting the movement to the fan, the clutch is also capable of controlling its speed at any time.
The power transmission, inside the clutch, is performed through a viscous fluid that acts as a link between the input shaft and the clutch frame, being the fan engaged to it. In this way, the fan speed control is carried out by managing the amount of viscous fluid in the clutch working chamber.
This fluid, normally made out of silicone oil, undergoes constant friction efforts, which are necessary to modulate the fan speed. This internal friction generates high temperatures that might even exceed 200ºC.
Due to the considerable increase of temperature generated in the interior of the clutch, this type of products are designed as a heat sink would. For this reason, a lot of ribs are added to its external contour in order to extend the area of heat transmission, with the aim of dissipating as much heat as possible.
Apart from external geometry, it is also taken into account the material of the clutch. Therefore, in order to manufacture these components, special aluminium alloys are selected with a high grade of heat dissipation.
However, it is necessary to consider more factors beyond heat dissipation for the design of these products. In Cojali, we select carefully each component so that it can undergo the most demanding working conditions. Therefore, O-rings, bearings and other internal components have specifications to work under very high temperatures and thus ensure the long useful life of our products without requiring constant maintenance.
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