Method and device for operating an internal combustion engine

A device for operating an internal combustion engine with an intake tract in which a switching device for modifying at least one of an effective intake pipe length and an effective intake tract volume is arranged, wherein the device is operable to determine an estimated intake pipe pressure dependent on at least one operating quantity of the internal combustion engine by means of a dynamic physical model,

• wherein the device is further operable to carry out an adaptation of the dynamic model dependent on a trimming value which is adaptively adjusted dependent on the estimated and a measured intake pipe pressure,
• wherein the device is further operable in the event that a modification of the switching position of the switching device is controlled, on the one hand to determine an estimated old position intake pipe pressure dependent on the model assuming the occupation of the previous switching position of the switching device subject to the prevention of the adaptive adjustment of the trimming value and on the other hand to determine an estimated new position intake pipe pressure dependent on the model assuming the occupation of the modified switching position of the switching device and prevention of the adaptive adjustment of the trimming value,
• and wherein the device is further operable to identify an actual switching position of the switching device dependent on a correlation check of the estimated old position intake pipe pressure and the estimated new position intake pipe pressure with respect to the measured intake pipe pressure.

A device for operating an internal combustion engine with an intake tract, comprising a switching device for modifying an effective intake pipe length and/or an effective intake tract volume, wherein the device is operable to determine an estimated air mass flow dependent on at least one operating quantity of the internal combustion engine by means of a dynamic physical model of the intake tract,

• the device being further operable
• to carry out an adaptation of the dynamic model dependent on a trimming value which is adaptively adjusted dependent on the estimated and a measured air mass flow,
• in the event that a modification of the switching position of the switching device is controlled, to determine on the one hand an estimated old position air mass flow dependent on the model assuming the occupation of the previous switching position of the switching device subject to preventing the adaptive adjustment of the trimming value and on the other hand to determine an estimated new position air mass flow dependent on the model assuming the occupation of the modified switching position of the switching device and prevention of the adaptive adjustment of the trimming value,
• and to identify an actual switching position of the switching device dependent on a correlation check of the estimated old position air mass flow and the estimated new position air mass flow with regard to the measured air mass flow.