Formula Design Of Antifreeze For Heavy Duty Engine

Antifreeze is a kind of heat transfer medium to ensure the heat transformation of locomotive engines,and it can remain high performance under all kinds of weather conditions.Antifreeze is composed by the base fluid and additives.Heavy duty engines require high anti-freezing and anti-boiling abilities of the antifreeze.At present,the main antifreeze which are applied widely in the markets is ethylene glycol.Although ethylene glycol has high anti-freeze performance,the antifreeze cost of ethylene glycol is expensive for the amount is huge.Meanwhile the ethylene glycol is easily oxidized under high temperature condition and produces corrosive products,thus the application of ethylene glycol is limited.In order to improve the corrosion resistance of ethylene glycol antifreeze and prolong its service life,it is to find suitable corrosion inhibitao.Therefore,investigating a high performance,low costing antifreeze formula has been the main direction in the present research and development.In this research,the optimal formula of base fluid and corrosion inhibitor was investigated.The antifreeze was tested by the coupon experiments,electrochemical analysis method and other analysis methods,the main results are showed below:1)The boiling point and freezing point of ethanol,ethylene glycol,glycerol,polyethylene glycol and polyvinyl alcohol were tested by the single factor experiment,and the suitable antifreeze was screened.Then the high performance and low costing base fluid formula was found by the orthogonal experiment and compounds analysis.The optimal base fluid was found to be glycerol 7.5%,ethylene glycol 38%,polyvinyl alcohol 0.2%,sodium hydroxide 0.5% and deionized water 53.8%,the boiling point of this solution is 123.5?,and the freezing point is lower than-33?.2)The critical factor to determine the anti-corrosion performance of antifreeze is the kind and content of antifreeze.The impedance test and metal coupon test of different kinds of corrosion inhibitor were conducted,and the influence factor levels were determined by the single factor experiment.The optimal formula of corrosion inhibitor found by the orthogonal experiment was urotropine 0.6%,triethanolamine 2%,benzotriazole 0.3%,sodium phytate 0.4% and deionized water 96.7%.3)The influence of chemical contents on the antifreeze performance was investigated.The optimal antifreeze formula was determined by the orthogonal experiment and costing analysis to be : glycerol 7.5%,ethylene glycol 38%,polyvinyl alcohol 0.2%,sodium hydroxide 0.5%,sebacic acid 3%,urotropine 0.6%,triethanolamine 2%,benzotriazole 0.3%,sodium phytate 0.4%,polyethylene glycol 0.02%,sodium benzoate 0.01%,sodium silicate 0.006%,and deionized water 47.464%,the boiling point is 140 and the fr? eezing point is lower than-33?.4)The mechanism of corrosion inhibitor was analyzed by electrochemical analysis method and corrosion test of metal plate.