Investigation of the Performance and Emissions of a Compression Ignition Mechanical Engine Operating in a Dual-Fuel Mode with Diesel and CNG

This study investigates the impact of adding compressed natural gas (CNG) to diesel on the performance of a compression ignition engine. In diesel dual-fuel systems, CNG is used to replace part of the energy originally supplied by diesel. The objective is to evaluate the performance of an Agrale BX6110 agricultural tractor engine operating in dual-fuel mode, with simple adaptations that allow it to function in its original mode as well, ensuring easy reversibility. Additionally, CNG can represent a cost-effective and environmentally advantageous alternative for farmers, significantly reducing their operational costs. Tests were conducted with four different CNG injection cases and three diesel injection cases, using an AW Dynamometer NEB 200 test bench. The maximum diesel substitution by CNG was 45.20%. In dual-fuel mode, the engine achieved maximum torque and power values of 665 N·m and 37.3 kW, respectively, representing a 20.45% loss compared to diesel-only operation. A reduction of 20.50% in carbon dioxide (CO2) emissions was observed, while unburned hydrocarbon emissions increased by approximately 4.52 times. Through economic analysis, it was concluded that, at the point of maximum torque and power operating in dual-fuel mode, a cost reduction of 14.32% per kWh produced was achieved.