The European REWARD project (REal World Advanced technologies foR Diesel engines) funded by the European Union within the Horizon 2020 framework aims to develop a new generation of Diesel engines complying with stricter post Euro 6 legislation under real driving conditions, and with lower fuel consumptions. Among the different technologies investigated, a fuel-efficient two-stroke Diesel engine suited for B- and C- class vehicles is designed and experimentally evaluated. Two-stroke engines offer high power densities resulting from doubling the combustion frequency compared with four-stroke engines. Despite this attractive advantage, the combustion occurring each revolution involves a very short time for the gas exchange processes and thus, a quasi-overlapping of the exhaust of burnt gases and the intake of fresh gases. This process is called scavenging and has to be properly optimized as it directly affects the overall efficiency of the engine.