The effects of fuel properties such as viscosity, sulfur and aromatics on diesel exhaust emissions were examined to recommend fuel specifications for future low-emission diesel engines. The amount of injected fuel increased as fuel viscosity increases because of the high elasticity and density of the fuel. Therefore, an increase in fuel viscosity significantly affected CO and smoke emissions under high load conditions. Higher fuel viscosity also resulted in larger spray droplets and affected THC emissions under low load conditions. Particulate emissions decreased with fuel sulfur content due to a decrease in sulfates and bond water. Wear in piston rings and cylinder liners of EGR-equipped engines decreased with sulfur content. Low-sulfur fuel reduced both particulate and NOx emissions. Fuel aromatics showed significant effects on particulate and NOx emissions. Gaseous and particulate emissions were little affected by mono-aromatics compound in fuel; however, they increased as a number of aromatics ring increased. SOF emissions increased considerably with three-ring aromatics. (A)
Abstract