The study investigates the performance and emission characteristics of a four-stroke, single-cylinder, and direct injection diesel engine with variable compression ratio using nanoparticles blended biofuel. The cerium Oxide (CeO2) nanoparticles have been blended in corresponding ratios with waste cooking oil (WCO) biodiesel. Further, response surface methodology (RSM) based Box-Behnken design (BBD) approach was used to evaluate engine performance parameters such as brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), and emission characteristics (such as NOx, CO, and CO2 emission). In addition, the quadratic models were obtained to investigate the influence of input parameters on each output response with analysis of variance (ANOVA). The desirability approach was used to obtain the optimal engine performance and emission characteristics. The analysis revealed that WCO blended with CeO2 nanoparticles fuel improves CI engines’ performance and reduces their hazardous emissions. The compression ratio of 14:1 at 10.29% blend composition and 50 ppm concentration level of nanoparticles with composite desirability of 0.858 was found to be the engine’s optimal operating conditions. At optimal conditions, BTE, BSFC, NOx, CO, and CO2 were 36.62%, 0.2204 kg/kW-h, 168 ppm, 0.0192%, and 1.132% respectively.

The present study investigates the tribological behavior of aluminum and silicon (Si) alloy (LM25) based hybrid metal matrix composite (MMC). LM25 alloy is reinforced with three different percentages (5, 10, and 15 wt. %) in a 1:1 ratio of sillimanite and red mud particles utilizing the stir casting method. An analysis of the microstructure shows morphology of reinforcement particles throughout the alloy matrix. Pin-on-disk tests have been performed as per the Box-Behnken Design (BBD) technique to evaluate wear and friction characteristics. Further effect of reinforcement, sliding velocity, and applied load on wear and friction characteristics were analyzed and optimize as 13.48 wt. % reinforcement, 10 N load and 1.5 m/s sliding speed to get optimum properties. SEM analysis showed that the composite surface was more susceptible to wear under high loads since it had a higher degree of deformation.