Comparative Study of Performance and Combustion Characteristics of Diesel and Methanol in Engines

Abstract

The growing interest in alternative fuels has prompted investigations into methanol as a potential substitute for conventional Diesel fuel in internal combustion engines. This study aims to compare the performance and combustion characteristics of Diesel and Methanol fuels across a range of engine speeds, with a particular focus on Brake Mean Effective Pressure (BMEP), Brake Torque, Brake Specific Fuel Consumption (BSFC), Heat Transfer Rate, and In-Cylinder Pressure. Experiments were conducted at engine speeds from 1500 to 5000 RPM, evaluating detailed thermodynamic parameters throughout the entire crank angle cycle. The results demonstrated that Diesel consistently produced higher BMEP values, peaking at 11.2 bar at 4500 RPM, compared to Methanol’s maximum of 10.2 bar. Diesel also achieved superior brake torque, recording 2100 N·m at 4000 RPM, while Methanol reached around 1800 N·m. The lowest BSFC was observed at 2500 RPM, with Diesel at 281 g/kW·h and Methanol at 282 g/kW·h, though both fuels exhibited increasing BSFC beyond this point, reaching approximately 297 g/kW·h at 5000 RPM. Diesel also attained a significantly higher peak in-cylinder pressure of 1900 bar compared to Methanol’s 1300 bar at 4000 RPM. A major novelty of this study lies in the comprehensive high-speed analysis and the integration of combustion, heat transfer, and mechanical performance indicators, which are less explored in previous works. Overall, Diesel demonstrated superior thermomechanical performance, while Methanol exhibited smoother combustion characteristics, offering potential benefits for engine durability.