Emission Reduction and Efficiency Gains in LHR Engines Using Natural Antioxidants in Biodiesel Blends

The study investigates the role of natural antioxidants (NA) derived from Albizia lebbeck leaves in enhancing the performance of Low Heat Rejection (LHR) engines using SBME20 biodiesel. LHR engines operate at higher temperatures and often face challenges like increased nitrogen oxide (NOx) emissions and biodiesel oxidation. The research explores the effectiveness of NA in improving fuel stability, combustion efficiency, and emission reduction. The experimental setup utilized an LHR engine with a zirconia coating on the piston and cylinder head. SBME20 biodiesel, a blend of 80% diesel and 20% sesame oil methyl ester, was tested with and without the addition of NA. Brake Specific Fuel Consumption (BSFC), Brake Thermal Efficiency (BTE), Smoke Opacity, and emissions were measured across various engine loads. Results show that the LHR engine with NA achieved superior fuel efficiency, reducing BSFC to 0.38 kg/kW-hr compared to 0.42 kg/kW-hr for conventional engines(CE). Emission reductions were significant, with CO emissions decreasing to 0.2 g/kWh, and NOx emissions remained controlled at 0.5 g/kWh at higher loads. The smoke opacity also decreased by 10%. NA additives offer a promising solution for improving biodiesel performance in LHR engines by enhancing combustion efficiency and reducing harmful emissions.