Tribological performance of Al2O3–SiO2/PAG composite nanolubricants for application in air-conditioning compressor

Abstract

Proper lubrication using nanoparticles helps to reduce friction and wear in air-conditioning compressor. The improvement in tribological behaviour of composite nanolubricants contributes in reduction of the compressor work. Tribological behaviour, such as coefficient of friction (COF) and wear rate performance, were investigated for an automotive air-conditioning (AAC) system compressor using Al2O3–SiO2/PAG composite nanolubricants under reciprocating test conditions to simulate a piston ring or cylinder liner contact. Al2O3 and SiO2 nanoparticles were dispersed in the Polyalkylene Glycol (PAG 46) lubricant using two-steps method of preparation for 0.01%–0.10% volume concentrations. A tribology test rig was used to measure COF and wear rate performance at different loads (2–10 kg) and speeds (200–300 rpm). The highest COF and wear rates reduction of composite nanolubricants was attained up to 4.49% and 12.99% at 0.02% volume concentration, respectively. Meanwhile, the lowest COF and wear rates reduction of 0.01% and 0.26% is reported at 0.01% and 0.06% volume concentration, respectively. No reduction in COF and wear rates occurred for volume concentrations of more than 0.06%. Therefore, it is recommended to use the Al2O3–SiO2/PAG composite nanolubricants with 0.02% volume concentration for application in refrigeration systems.