A durability study of a compression ignition engine operating with blends of neem vegetable oil with diesel

Abstract Blends of non‐edible vegetable oils with diesel fuel are considered a promising alternative for compression ignition (CI) engines in response to fossil fuel depletion and environmental concerns. Challenges to their commercial utilization include questions regarding the long‐term durability of these novel fuels. This study focuses on endurance, wear, and the breakdown of lubricating oil in a CI engine when operated on a pre‐heated blend of neem oil and diesel. For this purpose, a 272‐h endurance test was conducted as per IS 10000 standard, using the optimized pre‐heated B30 neem oil blend. We evaluated engine performance, wear of the primary components, condition of the lubricant, and the formation of deposits. In terms of B30 performance, optimum conditions (compression ratio = 22, injection timing = 23° CA BTDC, and injection pressure = 210 bar) resulted in a brake thermal efficiency of 34.99% and a brake specific fuel consumption of 0.29 kg/kWh which was better than traditional diesel. No mechanical failures or ring sticking were found, although some carbon deposits were present. A distinctive feature of this work is the unique long‐term analysis regarding the performance improvement, wear and detailed analysis, lubricant and visual deposits diagnostics on a preheated straight blend of neem oil. The findings show that the combustion quality and durability are significantly improved by preheating the fuel; thus, neem oil blends show sustainable and solid prospects for use in CI engines for agricultural and decentralized energy systems.