Auto radiator is one part of engine cooling technique. Other parts of this method consists of thermostat, drinking water pump, Cylinder waterway, Cylinder head waterway, fan etcetera.
To prevent overheat of the auto engine, components about the combustion chamber for example cylinder sleeve, cylinder head and valves need to have appropriate cooling. You can find 3 sorts of cooling device for inside combustion engine–h2o cooling, oil cooling and air cooling, among which h2o cooling is a major cooling way for auto engine. Circulating water in cylinder h2o way is used for cooling, then heated h2o will be led to the automobile raditor, finally back to the waterway after wind cooling.
As an illustration of cars, auto raditor cools down circulating h2o. It has flat shaped h2o pipe and corrugated shaped cooling fin, both are mostly made of aluminum. They are thermal performance oriented, and their installation direction is normal to the air flow direction, for this reason reduce wind resistense and improve cooling efficiency as far as possible.
Cooling water, also called cooling liquid, is not pure water but mixture of water (up to the standard of drinking h2o), antifreeze (always use ethanediol) and all types of preservatives of special utility. Thereinto, antifreeze account for 30% to 50% with the cooling liquid. This helps to improve the boiling point with the cooling liquid. In certain working pressure, the thermal rating from the cooling liquid can reach 120 degree celsius which happens to be higher than h2o boiling point and makes the liquid weak-volatilized.
To improve the cooling capacity of the auto radiator, a enthusiast is installed behind the radiator to make it possible for forced draft. Auto radiator used to be driven directly by crankshaft pulley belt. Thus, it has to start function once the engine starts to operate rather than depending on temperature variation with the motor. To adjust cooling capacity, adjustable louvers are added to the radiator and will act as wind conditioner. Now electromagnetic admirer clutch or electromagnetic fan are widely used on cutting-edge cars, and both are controlled by temperature transmitter. The clutch will separate with spindle under low temperature and then the enthusiast does not perform. But when temperature is high, power will be switched on by temperature transmitter which makes connection between clutch and spindle along with the enthusiast will start to work.
Auto radiator can hold h2o as well as dissipating heat. Yet, it has 3 drawbacks if we purely relied on radiator. First, the bibulous side from the h2o pump is easy to boil due to low pressure as well as the impeller tend to get cavitation erosion. Secondly, due to seperation of gas and water, a vapor lock is more likely to develop. Finally, cooling liquid is presumably boiled away under high temperature. Therefore,expansion vessel is developed by automobile designers. Its upper pipe connects with headpiece from the radiator and lower pipe with pump inlet. This could efficiently avoid above problems from happening. Nowadays, cars have more complex cooling technique than before, basically added temperature control elements which makes the radiator admirer more flexible to temperature variation.