Lucas Diesel Systems has designed a Common Rail fuel injection system for modern high speed direct injection diesel engines. The components of the system include a new high pressure pump, a rail, and injectors which accommodate a rapid control valve within the envelope of a 17 mm diameter. The injection pressure can be controlled at all engine operating conditions within the range of 150 to 1600 bar. This paper describes the major components of this system, which is designed to provide multiple injections into the combustion chamber during each engine cycle with a good control of small deliveries.In comparison with cam-driven diesel injection systems, the common rail approach needs some additional control and supervision strategies; for example, detection of small leakages due to high pressure at the needle seat throughout the engine cycle. A control philosophy has been implemented to ensure that the performance of the system is maintained at the design optimum by incorporating appropriate software strategy.