Abstract
In this paper a major demands posed in fro ut of fuel injection systems for a direct injection diesel engines has been discussed. The main desired features of fuel injection system are: extremely high injection prcssure, electronic control of injected quantity and timing and controlled rate of injection. A modem fuel injection concepts with electronic control -Unit pumps aud Unit injcclor systems and Common rail system and their characteristics has also been analyzed and their possibilities to satisfy desired demands discussed and compared.