Experimental Investigation of Biofuel Performance in Diesel Engines

Abstract

The increasing depletion of fossil fuel resources and rising environmental concerns have accelerated the exploration of alternative and sustainable energy sources for internal combustion engines. Biofuels derived from renewable biological sources have emerged as a promising substitute for conventional diesel due to their lower emissions and biodegradability. This study presents an experimental investigation of biofuel performance in diesel engines with a focus on engine efficiency, combustion characteristics, and emission behavior. The methodology involves the preparation of biofuel blends using biodiesel derived from vegetable oils and waste cooking oil, mixed with conventional diesel in varying proportions. The prepared fuel blends are tested in a single-cylinder diesel engine under different load conditions. Performance parameters such as brake thermal efficiency, brake specific fuel consumption, and mechanical efficiency are evaluated. In addition, emission characteristics including carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOx), and unburned hydrocarbons (HC) are analyzed using exhaust gas analyzers. The results indicate that biofuel blends exhibit slightly lower thermal efficiency compared to pure diesel at full load conditions; however, they demonstrate improved combustion stability and reduced harmful emissions. Significant reductions in CO and HC emissions are observed, while NOx emissions show a marginal increase due to higher combustion temperatures. It is also found that moderate blending ratios provide an optimal balance between performance and environmental benefits.