Development of an Engine Dynamometer Test for Rapid Evaluation of Engine Oil Degradation under High-Temperature, High-Load Conditions 2005-01-3821
An engine dynamometer test was developed to simulate the effects of high-temperature, high-load driving conditions on the rate of engine oil degradation. The test engine, a 3.4-L 60° V6, is operated at 3000 r/min and 103 Nm load for 125 h at elevated oil and coolant temperatures and without oil additions. Oil samples are collected at regular intervals and analyzed for chemical and physical properties. Results show that five different chemical and physical properties exhibit regular, predictable changes with operating time. By fitting all data to appropriate functional forms, a very precise fit is obtained (r2 typically > 0.97) for the rate of change in each parameter. When these changes are normalized and corrected for oil consumption, their average can be used to calculate an overall Performance Factor. Thus, this test can provide a rapid means to quantify the effect of different lubricants, operating conditions and hardware designs on engine oil life under high-temperature, high-load conditions. Results are presented on a comparison of the performance of mineral-based GF-2 and GF-3 quality lubricants, and the determination of the failure point of a GF-3 quality lubricant. Results are compared to data from high-temperature, high-load vehicle tests.