Method and device for controlling a combustion engine capable of lean running

Process for controlling a lean burn I.C. engine (10) of a vehicle containing a catalyst (14, 16) comprises acquiring the actual crude emission of at least one exhaust gas component of the engine; and determining the reliable lean temperature region depending on the crude emission of the exhaust gas component. An Independent claim is also included for a device for controlling a lean burn I.C. engine of a vehicle containing a catalyst. Preferred Features: A actual path-limited crude emission is acquired depending on a vehicle speed and the reliable lean burn temperature region is determined depending on the path-limited crude emission of the exhaust gas component. The exhaust gas component is nitrogen oxide and the catalyst is a nitrogen oxides storage catalyst.