Influence of advanced Diesel fuel properties on common rail injection system behaviour

Advanced injection system and reformulated "clean" fuels are two of the main research areas in development of low emission diesel engines. The new formulation of the fuels by means of the increase of paraffinic and olefine fractions and the use of oxygenated and bio-derivable compounds, changing the final product properties, can influence the injection system behaviour. To this aim the present paper describes the results of the experiments carried out on an injection test rig, employing ten different fuels. The fuel matrix was designed in order to obtain the variation of some parameters independently from the others. The injection system behaviour was analysed in terms of instantaneous flow rate and injection pressure. The results analysis indicates that the variation of some fuel properties, affecting the injection system behaviour, could need a recalibration of the whole engine in order to guarantee an effective improvement on both performance (maximum torque and rated power) and pollutant emissions.