Design, Casting and Performance Evaluation of Automotive Piston using Hybrid AA6061/SiC/Carbonized Coconut Shell Nanocomposite

Abstract

The application of conventional monolithic materials in automotive and aerospace components has resulted in huge fuel consumption, high operational cost and frequent components failure. Engineered materials have therefore gained popularity in recent decades owing to their excellent properties which enhance high fuel economy, reliability and low operational cost.  This study designed and fabricated an automobile piston using synthesized hybrid AA6061/silicon carbide/carbonized coconut shell nanocomposite. The hybrid nanocomposite consisted of AA6061 alloy reinforced with nanoparticles of carbonized coconut shell (CCS) and silicon carbide (SiC), combined in the ratio 1:1, and average particle sizes of 42.3 nm and 50.01 nm for SiC and CCS respectively. The composite samples (consisting of 3, 6, 9, 12 and 15% wt. each of the reinforcement materials), were produced by the stir casting method, and characterized for physical, mechanical, tribological and thermal properties. The composite with optimal properties (AA6061/SiC/CCS containing 9% wt. each of SiC and CCS) was used for the casting of the car piston. The fabricated AA6061/SiC/CCS nanocomposite piston was tested with Model 12 valve engine and the results obtained were compared with those of conventional piston and other investigators. The average fuel consumption of the engine using the fabricated piston, was found to be 0.00701 litres/kWh, resulting in a 16.83% savings in fuel consumption when compared with the conventional piston. Also, the density of the designed piston material reduced significantly by 8.5% of the density of the base alloy, resulting in efficient fuel saving, with ultimate tensile strength ranging from 176 – 249 MPa.