Investigating the Impact of Fuel Storage, Blend Composition, and Operating Parameters on Diesel Engine Characteristics Using an L16 Orthogonal Array

Abstract

The global imperative to reduce dependency on fossil fuels and mitigate environmental pollution has intensified research into sustainable alternatives for compression-ignition (CI) engines. This study presents a comprehensive investigation into the optimization of a single-cylinder CI engine's performance and emission characteristics using B20 ternary biodiesel blends derived from Jatropha, Pongamia, and Waste Cooking Oil (WCO). A robust statistical approach, the Taguchi L16 orthogonal array, was employed to analyze the simultaneous effects of four critical factors at four levels each: blend composition, fuel storage condition, engine load, and injection pressure. The performance metrics evaluated were Brake Specific Fuel Consumption (BSFC) and Brake Thermal Efficiency (BTE), while emission analysis focused on Oxides of Nitrogen (NOx), Carbon Monoxide (CO), and Unburned Hydrocarbons (HC). Analysis of Variance (ANOVA) was conducted on the Signal-to-Noise (S/N) ratios to determine the statistical significance and percentage contribution of each factor. Results indicated that engine load was the most dominant factor influencing BTE (58.31% contribution) and NOx (61.25% contribution). Injection pressure significantly affected BSFC (contributing to a lesser extent than load), CO (39.88%), and HC (42.54%). Adverse storage conditions, particularly elevated temperature and light exposure, were found to degrade fuel properties, leading to a quantifiable deterioration in engine performance and an increase in harmful emissions. A multi-response optimization revealed that while high load and high injection pressure improved thermal efficiency, they severely increased NOx emissions. The final optimized parameters, balancing performance and emissions, were identified as a blend of 50:50 Pongamia + WCO (B20), stored in dark conditions, operating at 75% load and an injection pressure of 200 bar. This study underscores the critical interplay between fuel formulation, storage stability, and engine operating parameters for the practical implementation of biodiesel fuels.