The socity of automotive engineers (SAE)established the first engine oil classification system based o viscosity in 1911.Six years later,L.A.Brown proposed that mineral oils be mixed with 0.1-0.2% red phosphours to inhibit oxidation.By 1920,Wels and southcombe has formaulated "Germ Process"lubricants,which were mineral oils admixed with small amounts of naturally occurring hiher fatty acids to improve their ability to wet metal surfaces and reduce fiction.Synthetic pour point depressants for lubricating oils were introduced 11 years later.
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