Method and device for operating an internal combustion engine with turbocharger

A process for operating an internal combustion emgine with an exhaust gas driven turbocharger (5) includes determining the exhaust gas mass in a volume (20) between one or more exhaust valves (25) of the internal combustion engine amd a turbocharger turbine (5). The pressure beyond the exhaust valve(s) (25) is determined from the exhaust gas mass using the general gas equation. The exhaust gas mass is determined by integrating the difference between the exhaust gas mass flowing into the volume (20) from the exhaust valve(s) (25) and the exhaust gas flowing out of the volume (20) composed of gas that has at least passed through the turbine. The exhaust gas mass gas flow out of the volume (20) is also formed from an exhaust gas mass current which flows out through an exhaust feedback channel (200). INDEPENDENT CLAIM is included for an apparatus for obtaining the back pressure.