Method for mixture forming in an internal combustion engine with a catalyst in the exhaust line

Catalytic converter Lambda-/oxygen sensor for the control of the stoicmetric ratio of air to fuel. The cylinder Lambda oscillation is subjected to a pre-control in respect to amplitude and/or frequency and/or oscillation mode as a function of the air mass and the catalyser oxygen storage capacity and its oxygen storage feed-out. This functions to increase oxygen storage to achieve the heating level required to meet the current engine load.