The D.I. Diesel engine injection strategies give special importance to the processes of spray penetration and mixture formation in the combustion chamber, because of their important role on soot and NOx formation. The purpose of this paper is to clarify in some way the influence of injection strategies by combination of optical diagnostics such as Laser Induced Exciplex Fluorescence technique (LIEF) and natural flame emission in a transparent D.I. Diesel engine of the production size. The influence of engine operating conditions, which are the presence of a pre-injection and swirl number is studied. Measurement of the injection rate and injected individual quantities is yield, then spray development is studied in the engine environment. Finally, by recording intensified pictures of the first reaction zones, it is shown how swirl intensification could influence the start of combustion.