Procedure to improve the exactness of the intake conduit of a combustion engine

The method involves computed a filling from an induction pipe pressure in an induction pipe model. A deviation of a detected lambda value from an anticipated value for the injected fuel mass and predicted filling and a difference between the predicted filling and that required to achieve the predicted lambda value are determined. Model parameters varied to give the required filling for the induction pressure for which the filling was computed. The method involves computed a predicted filling (20) from an induction pipe pressure using an induction pipe model (22), passing to a mixture controller (16) that determines the fuel quantity (14) to be injected into a combustion chamber (12) and continuously determining an exhaust gas lambda value with a lambda sensor (26). A deviation of the lambda value from an anticipated value for the injected fuel mass and predicted filling is determined, a difference between the predicted filling and that required to achieve the predicted lambda value is determined and the model parameters varied so that the model gives the required filling for the induction pressure for which the predicted filling was computed.