Studies on Lubrication Modification to Alter the Tribological Behaviour of Cylinder Liner-Piston Ring System

Undesirable friction can reduce the durability and effectiveness of machine parts. In this work, SAE 10W-30 engine oil is altered by adding graphite nanoparticles as additives aiming to reduce the friction between the cylinder liner and piston ring tribosystem. The friction reduction can potentially lead to enhanced engine performance, increased fuel efficiency, and greater longevity of engine parts. Using a four-ball tribometer, screening tests were performed to find the optimum concentration of nanoparticles needed to obtain minimal friction. The results showed that 0.06% graphite nanoparticle is the optimal level. Following the design of experiment approach, experiments were performed on a linear reciprocating tribometer with hypereutectic Al–Si cylinder liner-piston ring tribo pair under two loading conditions (120 and 200 N) using the altered SAE 10W-30 engine oil with 0.06% of nanoparticles lubrication. Based on the results, it is observed that a reduction of 16.56% in coefficient of friction (COF) at 120 N and 8.16% in COF at 200 N under the above lubrication conditions in comparison with the experiments performed using SAE base oil. The graphite nanoparticles function as solid lubricants, forming a protective layer on the surfaces of these components, thereby reducing friction.