Method and device for controlling an EGR system in a combustion engines

The present invention provides for a system for controlling NOx emissions based on the calculation of an error given by the difference between a first measured value obtained from a NOx sensor (7) and a second one estimated from a NOx estimation. Said sensor (7) can be used in an adaptation loop, where an open-loop or closed-loop EGR control system is adapted such that the expected NOx emissions (from the EGR controller) match the ones measured with the NOx sensor under steady-state conditions.