Thermal History of the Engine Oil and Its Effects on Low-Temperature Pumpability and Gelation Formation

Abstract

Low-temperature engine oil pumpability has been a concern for OEMs, engine oil formulators, and additive manufacturers for a number of years particularly since a significant number of air-binding failures in 1980 and '81. On careful investigation of the cause of such field failures, it was found that oil sensitivity to a particular combination of weather conditions was responsible. The experience also suggested that many other lowtemperature weather conditions might produce enginedamaging gelation. Thus, it seemed desirable to develop a bench test that would induce and measure gelation that might form in engine oil by continuously measuring slowly cooling oil over an extensive lowtemperature range. This led to the development of the Scanning Brookfield Technique (SBT) first reported in 1982. Oil supply lines to Atmospheric Pressure 3 Oil pump Oil in sump valve-train and crankshaft 'Air-Binding' Process Oil Screen

Cold cranking viscosity of used synthetic oils originating from vehicles operated under similar driving conditions

“…In the 1980s, issues related to oil gelling and the Scanning Brookfield Technique (SBT) have been thoroughly studied in connection with the failures of engines operating at low temperatures. 10 One of the methods for assessing low-temperature properties of oil is the use of cold cranking simulator (CCS). This is a relatively fast and accurate way of measuring the viscosity of engine oil at low temperatures.…”