New Accessories Save Horsepower Losses

Press, Volume XCIX, Issue 29389, 16 December 1960, Page 15

New Accessories Save Horsepower Losses

Two new devices which permit the cooling fans on engines to turn at varying speeds according to the requirements of the engine, are now being marketed in Great Britain and are already fitted to several new models. They are the “thermostatically controlled fan coupling” and the “torque sensitive coupling.” The torque-sensitive unit depends on a silicone fluid to transmit the torque from the engine necessary to drive the

fan. Basically, the driving section consists of two parts, whose surfaces are in close proximity, and between which is a film of liquid. The input member is driven directly by the fan pulley and causes the output member to drive the fan by the viscous drag between them.

The viscosity of the fluid may be chosen to give a fan drive characteristic which is very close to a direct drive from the engine at low speeds but permits a large amount of slippage to take place at higher speeds. The fan speed may be therefore limited to a value corresponding to the maximum cooling requirements of the engine, and the horsepower losses and noise of a fan running at an unnecessarily high speed is eliminated.

The temperature-controlled coupling provides the additional facility of thermostatic operation of the fan. Both these accessories make a valuable contribution towards a quietly-running car.