Air Motion and Fuel Distribution Requirements in High-Speed Direct Injection Diesel Engines:

This paper deals with the requirements for good combustion in the smaller high-speed direct-injection engines. Reference is made to the poor fuel distribution with current injection systems, and to the necessity of supplementary air movement. The level of air movement and the importance of squish motion are reviewed, and typical responses of the performance to swirl levels illustrated. From experimental evidence, including combustion photography, the mode of mixing is described, and its dependence upon the mass distribution of the fuel, and the influence of the chamber wall, discussed. The measurement of cylinder swirl under steady flow rig conditions is presented, and the correlation with chamber proportions and engine performance given. Recommendations are made on chamber requirements for wide speed operation and on inlet port configurations for optimizing flow and swirl conditions.