Technical Paper
Optical Investigation of Ignition Timing and Equivalence Ratio in Dual-Fuel CNG/Diesel Combustion
2016-04-05
2016-01-0772
Dual-fuel engines are recognized as a short-medium term solution to reduce fuel consumption and pollutant emissions of CI engines, while maintaining high energy efficiency. Methane (CH4) was chosen as it offers the best compromise between its heating value and H/C ratio. The high auto-ignition temperature of CH4 requires auto-igniting a small quantity of liquid diesel before it initiates the combustion of the mixture. Therefore, new engine operations need to be specifically developed. This investigation explores the impact of time sequences of injection of the liquid fuel on the ignition of homogenous methane/air mixture. Experiments were performed on a Rapid Compression Expansion Machine (RCEM), to reproduce the operating and dynamic conditions encountered in a diesel engine cycle, allowing visualizations of fuel injection and combustion processes through a transparent piston.
