Automotive antifreeze is a circulating medium for automotive engine cooling systems, the most common being water. Water has many advantages, such as: wide source, non-toxic, inexpensive, and good thermal conductivity. Water has long been used as a coolant for automotive engines. However, water has many disadvantages, such as high freezing point. When the temperature is lower than 0 °C, water freezes to increase the volume. It is easy to cause the water tank or the cooling system pipe to burst; the boiling point of water is low. When the engine is under severe conditions in summer, the water temperature will rise and even boil, which will affect the normal running of the car; the metal salts dissolved in the water It forms scale after heating and reduces heat transfer efficiency; water also rusts the metal. Therefore, people have been looking for a new type of coolant to replace water. First, the use of aqueous salt solutions (such as calcium chloride, magnesium chloride, sodium nitrate, sodium nitrite) can reduce the freezing point to below 30 ° C, but can not solve the problem of corrosion. Sugar and honey can also be used to lower the freezing point without corroding the metal, but it is expensive and has poor thermal stability. The use of kerosene and diesel as a coolant has a low freezing point, but it has poor heat transfer, is easy to burn, and has a swelling effect on rubber. Before and after the Second World War, methanol and ethanol were used as coolants. Although they are cheap and have low freezing point, they have low boiling point, are volatile, and are easy to burn. They are not ideal coolants. Later, people found that the performance of ethylene glycol aqueous solution is good, the freezing point can reach below -60 °C at a certain ratio, and the boiling point is above 110 °C, it will not damage the rubber hose, and it will not corrode metal after adding rust inhibitor. Relatively cheap, no unpleasant smell. Therefore, this liquid is currently widely used as a circulating medium for automotive cooling systems, called automotive antifreeze. When using ethylene glycol as a brine, it should be noted that the freezing point changes with the concentration of ethylene glycol in the aqueous solution. When the concentration is below 60%, the concentration of ethylene glycol in the aqueous solution increases, and the freezing point decreases, but the concentration exceeds After 60%, as the concentration of ethylene glycol increases, the freezing point increases and the viscosity increases with increasing concentration. When the concentration reaches 99.9%, the freezing point rises to -13.2 °C, which is an important reason why the concentrated antifreeze (antifreeze) can not be used directly, and must be noticed by the user.
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SH/T 0521-1999
"Ethylene glycol type coolant for automotive and light duty engines
》, transportation industry standard "Technical Conditions for Safe Use of Automotive Engine Coolant" (GB 29743-2013
"Motor Vehicle Engine Coolant"). Some automotive companies have also developed coolant specifications, such as Honda's coolant specifications, which are based on the specifics of their respective engines.Dongguan Yuantong Technology Co., Ltd. is a professional production of each block cutting machine, flat mouth machine, folding machine, express bag machine, Pearl Cotton Bag Cutting Machine, slicing machine, degradation bag cutting machine, all kinds of plastic bag mold, punching machine, electrosick machine and other supporting equipment, and according to the special requirements of customers design and production of special equipment.
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