<div class="htmlview paragraph">In order to develop modern two-stroke engines with low fuel consumption, respectively with low exhaust emissions, two alternative development areas - the mixture formation and the scavenging system - have been correlated. For a satisfying mixture formation without fuel losses by scavenging, the direct injection seems to be one of the best solution for the high speed two-stroke engine of the future. On the other hand the modern development of two-stroke scavenging systems shows a large field of application and improvement methods of cross and loop scavenging [<span class="xref">1</span>].</div> <div class="htmlview paragraph">Based on the specific optimisation factors of the injection system, respectively of the scavenging system, the aim off this common work of the Universities of Pisa and Zwickau is to correlate both the optimisation fields in an advantageous mixture formation process. The principal elements of this correlation are the design of the combustion chamber, the position of the injection nozzle, the characteristic of the spray jet respectively the direction and velocity of the scavenge air induced into the cylinder.</div> <div class="htmlview paragraph">This paper presents the research co-operation between the mentioned Universities regarding this subject, consisting in the simulation of the flow characteristics of the injected fuel and scavenge air -separately and combined- study which is performed by the CFD code FLUENT.</div>