Development of a Novel High-Throughput Laboratory Instrument to Simulate High Temperature Lubricant Deposit Formation
A high-throughput laboratory deposit test has been developed which correlates well with piston deposit formation in the ASTM Sequence IIIG engine test and has excellent repeatability. The test utilizes (a) bulk oil oxidation zone, simulated by maintaining a 50:50 mixture of used taxi oil and the test lubricant at 140-180 C and (b) a high temperature thin-film oxidation zone (270-300C). A ‘hot tube’ design controlled by air pressure is used to draw the bulk lubricant repeatedly into the high temperature zone where thin film lubricant oxidation and deposit formation occurs on the inside of the hot glass tube. An optical sensor is used to continuously monitor deposit formation at selected tube locations, and the entire glass tube can be optically rated at the completion of the test. The automated rig is capable of testing several batches of 12 lubricant samples per day.