This paper describes the development of a turbocharger model in a Diesel engine fitted with LP and HP EGR loops, and its reduction in order to provide a control oriented model. This work complements previous works already published or submitted ( Moulin et al. [2008], Youssef et al.
[2007] and Grondin et al. [2009]). Experimental validation results are presented, justifying the assumptions made in the model reduction process. The turbocharger control strategies designed from this model combined with an adequate EGR control and estimation provide a solid basis for the management of modern Diesel engines. In particular, the calibration of a complex air system could be a daunting task. In the proposed structure the effort required is greatly reduced thanks to an adequate physical representation of the system.