Nocera, E., Bruno, R., Silva, D., and Bieneman, J., "High Durability and Low Fuel Consumption Ring Pack for HDD Engines," SAE Technical Paper 2013-01-1725, 2013, doi:10.4271/2013-01-1725.
Modern engine manufacturers are under pressure to continuously improve the performance of diesel engines. Government requirements and customer demands drive significant changes to power cylinder designs. Great efforts are being made to reduce emission levels and increase operating efficiencies. The power cell unit (PCU) environment is becoming more aggressive at the same time that peak cylinder pressures are increasing. Engines are expected to perform at this high level throughout their operating life with little to no degradation in performance. Besides that, greater emphasis is also being placed on fuel efficiency of the engine.In order to meet these challenges the design of a modern ring pack should consider the utilization of high wear resistance coatings aligned with new geometries to enhance oil film control and reduce friction. This paper includes developments for the entire ring pack with extra emphasis placed on the development of the scraper ring (lower compression ring) and the oil control ring. The technology presented will include the application of coatings by physical vapor deposition technology and the application of a new profile on the outer diameter of the oil control ring. The performance benefits of the changes to ring coatings and geometry will be explained using rig and engine test results.