Performance Evaluation of a Compression Ignition Engine Fueled with Biodiesel Blends Derived from Waste Cooking Oil

Abstract

Waste cooking oil (WCO) is a low-cost lipid feedstock that can be converted into fatty-acid methyl esters and used as a renewable substitute for petroleum diesel. The present methodology paper develops a reproducible experimental framework for evaluating the performance and exhaust-emission behavior of a compression ignition (CI) engine fueled with WCO biodiesel-diesel blends. The proposed study begins with filtration and moisture removal from collected WCO, followed by base-catalyzed transesterification, phase separation, washing, drying, fuel-property characterization, blend preparation, and engine testing. Five fuels are considered: B0, B10, B20, B30, and B100, where the numerical value denotes the volumetric percentage of WCO biodiesel. Tests are conducted on a single-cylinder, four-stroke, direct-injection diesel engine at constant speed and multiple load points. Brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), exhaust-gas temperature (EGT), carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), and smoke opacity are used as the principal response variables. Literature published up to 2016 indicates that moderate WCO biodiesel blends can maintain engine efficiency close to diesel while reducing CO, HC, and particulate-related emissions, although NOx trends can vary with engine design, injection settings, load, and biodiesel fraction. The methodology therefore emphasizes repeat testing, fuel-property control, and statistical comparison so that the optimum blend is selected from a combined performance-emission perspective rather than from a single metric.