- Almost stationary control of the correct EGR rate (Exhaust Gas Recirculation) is state of the art. More aggressive emission tests such as WLTP and RDE require a dynamic control of the EGR rate, otherwise a too low EGR rate results in increased NOx emissions, a too high EGR rate in particulate emissions. The difficulty in any EGR control is the missing plant knowledge; the EGR rate is controlled although the present EGR rate is not exactly known. EGR flow sensors are available, but due to additional costs they have not found a broad acceptance. A different approach for high pressure EGR investigated in this paper is a control using a second lambda sensor between EGR and inlet valves. This approach improves the dynamic response, but it might come with costs similar to an EGR flow sensor. Alternatively a model based approach can be used which shows high potential.