Impact of nozzle holes configuration on fuel spray, wall impingement and NOx emission of a diesel engine for biodiesel-diesel blend (B20)

A diesel engine fueled with biodiesel-diesel blend (B20) decreases CO, HC and smoke emissions drastically. However, NOx emission and chance of wall impingement increased significantly leading to the problems of the diesel engine for use of the biodiesel-diesel blend. Hence, the study is aimed at reduction in NOx emission of the engine at source level and chance of wall impingement using the modified nozzle configuration (5 (base) and 6 (modified) holes). NOx emission of the engine for B20 fuel decreased from 7.4 g/kW-hr with the base nozzle configuration to 6.6 g/kW-hr with modified nozzle configuration due to reduction in in-cylinder temperature, retarding in dynamic injection timing, reduction in spray penetration distance. The spray penetration distance for B20 with the modified nozzle configuration is lesser resulting in less chance of wall impingement resulting in solution to the main durable issues of diesel engines for B20. The spray characteristics including sauter mean diameter, penetration distance and air entrainment are analyzed for B20 fuel in detail. The NOx emission is well correlated with spray penetration distance. The modification of nozzle configuration (number of holes) is a solution to reduce NOx emission of biodiesel fueled diesel engine at source level and also the chance of wall impingement with tangible benefits of HC, CO, smoke and BSEC reduction.