Combustion and exhaust emissions characteristics in the supercharged engine ignited with gas oil fueled by pyrolysis gas generated from biomass

Pyrolysis gas produced from woody and waste biomass is considered as one of very important fuels to establish a sustainable society. In this study, a supercharged single cylinder gas engine with micro pilot ignition by gas oil was used. This ignition system has an advantage of large energy source, long period for ignition and stable ignition compared to the spark ignition system. Four types of artificial pyrolysis gases that were compressed into high pressure vessels were used. Compositions of these gases were H₂, CO, CO ₂, CH₄ and N₂. Combustion was visualized by using a high-speed color video camera from the bottom of the quartz piston. The pressure history was analyzed to obtain the rate of heat release in order to investigate combustion characteristics. Exhaust emissions of NO_x, HC, CO and smoke were measured. Many ignition kernels produced by the iginition of gas oil initiate flame propagation of gas/air mixture and then flames move toward the wall of cylinder. Effects of injection timing, gas composition and equivalence ratio on engine performance were studied.