Study of diesel engine emission and fuel economy requires a basic understanding of fuel-air mixture formation processes, which is because of significant dependence of diesel combustion performance on the fuel spray injection into the combustion chamber. This paper reviews recent investigations on diesel spray structure, which include internal flow of the nozzle, the breakup behavior of a liquid jet, spray tip penetration, and drop size distribution. Their corresponding empirical equations are also presented. Based on those equations, a phenomenological simulation model has been developed to predict the combustion performance, thermal efficiency, and diesel emissions.
