There are mainly two types of car radiators: aluminum and copper. The former is used in general passenger cars, while the latter is used in large commercial vehicles. The materials and manufacturing technologies of automotive radiators have developed rapidly. Aluminum radiators, with their obvious advantage in material lightweighting, are gradually replacing copper radiators in the fields of cars and light vehicles. At the same time, the manufacturing technology and process of copper radiators have made considerable progress. Copper hard brazed radiators have obvious advantages in the engine radiators of buses, construction machinery, heavy trucks, etc. Most of the radiators used in foreign cars are aluminum radiators, mainly considering environmental protection (especially in Europe and America). In the new types of cars in Europe, the average proportion of aluminium radiators is 64%. From the perspective of the development prospects of automotive radiator production in our country, the number of aluminum radiators produced by hard brazing is gradually increasing. Hard brazed copper radiators are also applied in buses, trucks and other engineering equipment.
The radiator of a car is an indispensable and important component in the cooling system of a water-cooled engine in a car, and it is developing towards being lightweight, efficient and economical. The structure of automotive radiators is also constantly adapting to new developments. The core of the tube-fin radiator is composed of many thin cooling tubes and heat dissipation fins. The cooling tubes mostly adopt a flat circular cross-section to reduce air resistance and increase the heat transfer area. The core of the radiator should have sufficient flow area to allow the coolant to pass through, and at the same time, it should also have sufficient air flow area to allow a sufficient amount of air to pass through to carry away the heat transferred from the coolant to the radiator. At the same time, it must also have a sufficient heat dissipation area to complete the heat exchange among the coolant, air and heat sink. The tube-belt radiator is made by welding corrugated heat dissipation tubes and cooling tubes arranged alternately. Compared with the tube and sheet type heat sink, the tube and strip type heat sink can increase the heat dissipation area by about 12% under the same conditions. In addition, the heat dissipation strip is equipped with holes similar to louvers that disturb the airflow, so as to break the adhesion layer of the flowing air on the surface of the heat dissipation strip and improve the heat dissipation capacity.
The function of a car's cooling system is to keep the car within an appropriate temperature range under all working conditions. The cooling systems of automobiles can be classified into air-cooled and water-cooled types. Those that use air as the cooling medium are called air-cooled systems, and those that use coolant as the cooling medium are called water-cooled systems. A water cooling system is typically composed of a water pump, radiator, cooling fan, thermostat, compensating water bucket, engine block, water jacket in the cylinder head, and other accessory devices. Among them, the radiator is responsible for cooling the circulating water. Its water pipes and heat sinks are mostly made of aluminum. The aluminum water pipes are made in a flat shape, and the heat sinks are wavy, emphasizing heat dissipation performance. The installation direction is perpendicular to the direction of air flow, striving to minimize air resistance and achieve high cooling efficiency. The coolant flows inside the radiator core, while air passes outside the radiator core. The hot coolant cools down by dissipating heat to the air, while the cold air warms up by absorbing the heat released by the coolant. Therefore, a radiator is a heat exchanger.
