Internal combustion Engine can be cooled by air-cooling or water-cooling method. Various Water Cooling Methods Of I.C.Engine is covered in earlier post, which you can refer to know in details. Impeller Thermosyphon system has required following components to perform the cooling action.
The function of the radiator is to cool down the hot water from engine. It consists of a large number of vertical tubes through which water flows down. The temperature of water is reduced appreciably by drawing the air through spaces between the radiator tubes with the help of fan, which is mounted on the impeller spindle driven by a suitable pulley arrangement.
There are many types of radiator tubes are used in field but the most common is tubular type. It consists of a large number of circular brass tubes pressed into a number of suitable punched parallel brass fins. The tubes are tinned to guard against corrosion and are staggered. The main disadvantage of this design is, a greater inconvenience to repair any damaged tubes. Still it is cheaper than the honeycomb type design due its initial cost. The honeycomb radiator is used in racing cars.
The water used for cooling must be soft because the deposits given out by hard water act as insulator of heat between the cylinder walls and the radiator water, but in case where soft water is not available, 0.03 kilogram of sodium bichromate should be added for every 13 kilogram of water.
The maximum temperature, which can be allowed in a radiator, is 3 degree centigrade below boiling point of water. The ratio of the observed temperature difference to the greatest permissible temperature difference in a radiator is called suitability of of the radiator.
Some radiators are equipped with a heater, which not only averts the danger of freezing of water but also greatly reduces the time taken by the engine to reach its normal operating temperature.
02) Fan and Pump:-
The pump increases the velocity of water through the system. The fan, which draws air through the radiator spaces, is usually mounted on the same spindle as that of the impeller having widely spaced vanes to facilitate the flow of water through it is case of failure.
The bottom of the radiator is connected to the suction side of the pump. The power is transmitted to the pump spindle from a pulley mounted on the end of the camshaft or crankshaft.
A thermostat fitted in such a manner that it prevents the flow of water below certain temperature, from engine to the radiator. The "Bellows Type" thermostat is generally used.
The disc is connected to the bronze bellow through link. The bellows are sealed against the atmosphere and contain alcohol inside it. On cooling, the bellows contract due to the condensation of alcohol vapour into liquid. The disc therefore closes the passage, which could be reopened only if a certain minimum temperature of the circulating water is reached which expands the bellow due to evaporation of the alcohol liquid inside. Generally, a thermostat does not allow the water to flow below 70 degree centigrade.
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