Computer Data Acquisition With Statistical Processing in Dynamometer Testing of Fuel Efficient Engine Oils

Automated data acquisition and linear regression methods have enabled an analysis of test precision factors in measurements of brake specific fuel consumption for assessment of fuel efficient engine oils. Critical engine parameters were identified, controlled, and measured using a high resolution data acquisition system. With other critical parameters held within less than ±.03% of specified levels, air-fuel ratio was identified as the limiting factor in overall test error. A variety of experiments involving back-to-back tests (including engine mapping sequences) with the ASTM 20W-30 reference oil and calibration oils yielded overall test delta repeat errors between .19% and .56%.