Reduced Power Cylinder Friction with Advanced Coatings and Optimized Lubricants 2022-01-0523

The engine power cylinder is comprised of the piston, piston rings, and cylinder. It accounts for a significant amount of total engine friction within reciprocating, internal combustion engines. Reducing power cylinder friction is key to the development of efficient internal combustion engines. However, isolating individual power cylinder tribocouples for detailed analysis can be challenging. In this work, a new reciprocating liner test rig is developed and introduced. The rig design is novel, using a stationary piston and a reciprocating cylinder liner. Friction is calculated from the force measured in the connecting rod which supports the piston. The rig allows for independent control of peak cylinder pressure, speed, and lubricant temperature. Using the newly developed test rig, several technologies for friction reduction are evaluated and compared. Friction reducing technologies include the use of a low-friction TiSiCN nanocomposite coating applied to the piston rings, a lubricant viscosity study with engine oils ranging between SAE 0W-16 to SAE 10W-40 viscosity grades, and the impact of a special organic friction modifying oil additive. Results indicate that significant reductions in friction may be obtained using specialty coatings and optimized lubricating oils. Finally, results from the new reciprocating liner test rig are compared to data generated in chassis dynamometer vehicle fuel economy testing, showing excellent agreement.