Effect of Top Piston Ring Wear on Its Sealing and Scraping Performance

New engines are presenting a constant increase of mechanical and thermal loads. The engine components should guarantee similar, or superior, performance than the baseline components in spite of the unfavorable wear conditions. For piston rings, the performance is given by the ring capacity of sealing and scraping. This performance can be measured in an engine by the lube oil consumption (LOC) and the gas flow to the crankcase (Blow-by) results. The purpose of this work is to evaluate the top piston ring wear influence on its sealing and scraping performance. Two engines were tested, one Otto and the other Diesel, in a dynamometer in order to quantify the top ring dimensional variation due to wear. Numerical simulations were performed in order to evaluate the individual influences of each dimensional parameter. The results of LOC and Blow-by were compared to literature data and engine test results of each engine. A proposal of combined effects among the dimensional parameters is presented.