The employment of mechatronic systems enhances the flexibility of an already developed engine: a flexible monitoring and control system would allow to comply with different emission standards, thus making an engine available for different countries. The adaptation of this system may also allow a manufacturer to extend the production of an existing engine, even if new restrictions on pollutant emissions are prescribed. For example, the introduction of a Diesel Particulate Filter (DPF) allows to easily reach Euro 4 prescriptions, while the installation of an Exhaust Gas Recirculation (EGR) valve on gasoline engines is necessary to comply with the Euro 4 standard.