Patent ID: 8245566
Filing Date: 2012-08-21
Classification: F02D,G01N

Abstract:
1. A procedure for diagnosing the increasing speed and the dead time of an exhaust gas probe, which is arranged in the exhaust gas duct of a combustion engine, whereby the diagnosis is carried out due to a comparison of a modeled and a measured signal after a default change of a fuel air ratio of an air fuel mixture that is supplied to the combustion engine and whereby the signal is an output signal of the exhaust gas probe or a modeled or measured signal that is derived from the output signal wherein a first extreme value is determined in the course of the modeled signal and in that a first point of time and a first starting value are determined if the modeled signal deviates by a default amount from the first extreme value, in that a second extreme value in the course of the measured signal is determined and in that a second point of time and a second starting value are determined, if the measured signal deviates from the second extreme value by a pre-determined amount, in that a first integral is created over a pre-determined period of time, beginning at the first point of time above the different between the first starting value and the modeled signal, and in that a second integral is created over a second period of time, beginning at the second point of time, above the difference between the second starting value and the measured signal, in that the second period of time is equal to the pre-determined period of time or in that the end of the second period of time related to the point of time of the change of the fuel air ratio or related to a first point of time is determined and in that from a quantitative comparison between the first integral and the second integral a quantitative comparative value is created, which indicates the increasing speed and/or the dead time of the exhaust gas probe.