Reducing fuel consumption of a light-duty vehicle by incorporating CuO nanoparticles in compressor lubricant of air-conditioning system

This experimental study aims to investigate the effects of copper (II) oxide (CuO) nanoparticles (~50 nm, 99.9% trace metal basis) incorporation in polyalkylene glycol (PAG) lubricant of a compressor included in air-conditioning (AC) system of a light duty passenger car. Observations on fuel consumption in real-world driving tests while the AC system is fully running were conducted. In order to determine the impacts of CuO nanoparticle incorporation in PAG oil, friction (pin-on-disc tribotester) and wear tests were carried out along with surface visualization analyses of scanning electron microscopy (SEM) and atomic force microscopy (AFM) on the disc samples laser-cut from the spare AC compressor vanes. Morphology and thermal stability of the CuO nanoparticles were also investigated via SEM and thermal gravimetric (TG) analyses, respectively. Wear rate (WR), average coefficient of friction (µa) and surface roughness analyses on the specimen surfaces were conducted to procure a comprehensive knowledge about the tribological improvement of CuO nanoparticles. All analyses were repeated on the identical metal samples in PAG lubricant bath (PL) and CuO nanolubricant (NL) separately under the same conditions and average of the test results were taken into account to minimize error. The results demonstrate that reductions of 15.5% in average coefficient of friction, 33% in wear rate and 9% in average surface roughness were achieved resulting in a decrease of 7.7% in fuel consumption at designated driving conditions.