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Nine engine oils were evaluated in two GM vehicles: a 1993 Pontiac Grand Am with a 2.3L Quad4 engine and a 1993 Buick LeSabre with a 3.8L (3800) V-6 engine. Standard EPA (Environmental Protection Agency) fuel economy (FE), vehicle-dynamometer tests were conducted. The results were compared with the fuel economy obtained with a standard ASTM reference oil (BC). The vehicle data from this program were used in evaluating the new engine-dynamometer ASTM Sequence VI-A test designed to predict “real world” fuel economy in vehicles. EPA 55/45 combined fuel economy performance in the GM vehicles ranged from almost 2 percent improvement (over the BC oil) for an SAE 5W-20 oil, to over 2 percent poorer fuel economy than the reference oil for an SAE 20W-50 oil. The two different engines responded similarly to the different oils and showed similar trends.

This paper presents an overview of techniques for measuring friction using bench tests and fired engines. The test methods discussed have been developed to provide efficient, yet realistic, assessments of new component designs, materials, and lubricants for in-cylinder and overall engine applications. A Cameron-Plint Friction and Wear Tester was modified to permit ring-in-piston-groove movement by the test specimen, and used to evaluate a number of cylinder bore coatings for friction and wear performance. In a second study, it was used to evaluate the energy conserving characteristics of several engine lubricant formulations. Results were consistent with engine and vehicle testing, and were correlated with measured fuel economy performance. The Instantaneous IMEP Method for measuring in-cylinder frictional forces was extended to higher engine speeds and to modern, low-friction engine designs.