Effect of cylinder deactivation on tribological performance of piston compression ring and connecting rod bearing

Thermo-mixed-hydrodynamics of compression rings and big-end bearings are presented. Frictional losses under normal engine operating conditions for a gasoline engine and those with cylinder deactivation (CDA) are predicted. With CDA, the combustion chamber pressure increases in the active cylinders, whilst some residual pressure remains in the deactivated ones. For the former, the increased in-cylinder temperatures reduce viscous friction, whilst reducing the load carrying capacity, promoting increased boundary interactions. In deactivated cylinders, lower contact temperatures yield increased viscous friction. Overall, a 5% improvement in expended fuel is expected with the application of CDA. However, 10% of these gains are expended due to increased friction. The study demonstrates the need to consider total system effects when introducing new technologies such as CDA.