What properties should automobile air conditioning refrigerant have?

Engine coolant should have the following properties.

First, the freezing point is low and the boiling point is high. Freezing point is the temperature at which the coolant begins to crystallize without supercooling. The boiling point is the temperature at which the coolant begins to boil when the engine cooling system is in balance with the external atmospheric pressure.

Second, it has good corrosion resistance and does not damage the organic paint of the car. In order to make the engine coolant have good corrosion resistance, it is necessary to keep the coolant in an alkaline state; Engine coolant is a mixture of chemical substances, which is easy to contact with the organic coating of the automobile when filling, so it is required that the engine coolant should not have adverse effects on the organic coating of the automobile.

Thirdly, the scale is not easy to generate and has good foam resistance, which has a great influence on the heat dissipation intensity of the engine cooling system; If the engine coolant produces too much foam, it will not only reduce the heat transfer efficiency, aggravate cavitation, but also lead to coolant overflow. 8. 1.2 specifications of engine coolant At present, the coolant widely used in automobiles is a mixture of chemicals such as ethylene glycol or propylene glycol and water in a certain proportion, and additives such as corrosive agent, cleaning agent, scale inhibitor and colorant are added. Typical engine coolant specifications abroad are formulated by American Society for Testing Materials (ASTM). The current implementation standard of automobile engine coolant in China is SH 052 1- 1999 "Ethanol Coolant for Automobile and Light-load Engine". Coolant is divided into six brands according to freezing point: -25, -30, -35, -40, -45 and -50. There are many kinds of antifreeze for automobiles, including calcium chloride (CaCl2) in inorganic substances, methanol (CH3OH) in organic substances, ethanol (C2H5OH, common name alcohol), ethylene glycol (C2H4(OH)2, common name sweet alcohol), glycerol (C3H5(OH)3, common name glycerol), lubricating oil and sugar and honey that are common in our daily life. Add a proper amount of pure soft water (water without calcium and magnesium ions or water with little calcium and magnesium ions, such as distilled water, unpolluted rainwater and snow water, etc.). ), the total hardness concentration of water quality is between 0 and 0-30ppm.

I hope it will help you and I hope it will be adopted.