The paper considered the issue of choosing injection spray nozzle parameters in the fuel feeding system of the diesel engine. The authors proposed a method of analytical determination of the coefficient in the calculation model of the dispersed jet motion. There were presented the analytical correlation between the main parameters of the injection process: pressure, density, fuel consumption, speed drops, length of the jet, geometric dimensions of the atomizer and other calculation examples. Experimental data confirm the adequacy of the main provisions of the estimated model. The position of the new methodology was identified in the overall structure of the rapid assessment method for workflow settings of the diesel engine.