Performance and Emission Analysis of Biodiesel Blends in Diesel Engines: Comprehensive Review

Abstract

This review takes a closer look at how biodiesel blends perform in diesel engines, with a focus on their potential as cleaner and more sustainable alternatives to traditional fossil fuels. Biodiesel, which is made from renewable sources like vegetable oils and animal fats, offers key environmental advantages most notably, lower greenhouse gas emissions and better biodegradability. Drawing from both experimental research and simulation studies, the review explores how various blend ratios (B10 to B50) affect engine behavior, including fuel efficiency, combustion characteristics, and overall performance. It also compares emissions of major pollutants such as carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOₓ), and particulate matter (PM) with those from conventional diesel. The results generally show that biodiesel blends help reduce CO, HC, and PM emissions, although they tend to increase NOₓ emissions, likely due to higher oxygen content and combustion temperatures. At lower blend levels, engine performance stays close to that of pure diesel, with only slight drops observed at higher blends. The review also discusses practical concerns like oxidation stability, cold weather performance, and long-term effects on engine parts. Overall, the findings suggest that biodiesel blends are a promising step toward cleaner transportation, though there are still technical challenges to overcome and areas that call for further study and innovation.