Feasibility and Performance Characterisation of a Dual-Fuel Engine Automobile Using Premium Motor Spirit (PMS) and Compressed Natural Gas (CNG).

Abstract

The increasing environmental and energy challenges associated with Premium Motor Spirit (PMS) in spark-ignition engines necessitate the exploration of alternative and cleaner fuels. This study investigates the feasibility and performance of PMS–Compressed Natural Gas (CNG) dual-fuel operation using a validated Computational Fluid Dynamics (CFD) framework in ANSYS Fluent. A high-fidelity 30° sector model of a single-cylinder engine was developed, incorporating PMS direct injection and CNG port injection, with simulations conducted across substitution ratios of 0–40%. Mesh independence and time-step sensitivity analyses were performed to ensure numerical reliability, and validation against experimental benchmarks confirmed deviations within ±5%. Results show that moderate substitution (20–30% CNG) achieves the most effective balance, maintaining brake thermal efficiency at ~38.8% and limiting power losses to less than 6%, while reducing CO₂ and NOₓ emissions by 22% and 26%, respectively. These findings demonstrate the potential of PMS–CNG dual-fuel technology as a cost-effective transition pathway toward sustainable transport, particularly in regions such as Nigeria where natural gas infrastructure is expanding. The study also provides systematic CFD-based optimization and detailed insights into in-cylinder flow dynamics, offering a valuable complement to experimental research.