Impact of nanoadditives on lubricant performance under real-operating conditions: Engine performance study and wear analysis

This study investigates the impact of incorporating two distinct nanoadditives, Graphene Oxide (GO), and Detonation Nanodiamond (DND), into standard internal combustion engine (ICE) lubricant to reduce friction and wear under real operating conditions. Experiments on a single cylinder gasoline engine reveal enhanced brake thermal efficiency and reduced friction and wear on the piston ring, with up to a 21% increase in efficiency at half load using 1 mg/l of GO. The DND-based nanolubricant demonstrates superior engine performance compared to the base lubricant. Both nanoadditives, at a maximum weight percentage of 0.01 gm/l, exhibit unique properties – spherical DND nanoparticles act as a nano ball-bearing, while flake-like GO nanoparticles minimize friction and wear by reducing the contact area between the mating surfaces. The use of nanoadditives increases crankcase lubricant temperature by up to 17.5%, attributed to enhanced thermal conductivity and improved convective transfer. The surface analysis of used piston rings shows reduced wear with the entrapped nanoparticles. X-ray photoelectron spectroscopy (XPS) analysis reveals a 40 nm thick tribofilm on used piston rings, highlighting the contribution of nanoadditives in wear reduction mechanisms. This research underscores the potential of nanoadditive-enhanced lubricants for improving engine efficiency and durability in real-operating conditions.