Search Results

Engine design and tribology engineers are constantly challenged to develop advanced products with reduced weight, reduced friction, longer life, and higher engine operating temperatures. The resulting engine systems must also meet more demanding emissions and fuel economy targets. Advanced energy-conserving lubricants and surface coatings are concurrently evolving to meet the needs of new engine materials. Because of the enormous cost and time associated with engine testing, much interest is being focused on the development of representative and repeatable bench tests for evaluation of engine materials and lubricants. The authors have developed a bench test employing reciprocating motion for evaluating friction and energy-conserving characteristics of lubricants.

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.