The engine air-path has become a crucial part in the development of modern engines. The control of the air-path has a direct impact on the engine performance as well as on its pollutant emission level. Indeed, air system strategies allow controlling the species that are introduced in the cylinder, which is a cost-effective way to reduce pollutant emissions. As a consequence, the automotive air systems have become increasingly complex in order to achieve pollutant reduction strategies and to allow fuel consumption reductions. In this context, this thesis focuses on the modeling and control of the air-path of Diesel engines. We divide this work into short-term developments and medium-long term developments.