Patent ID: 8826722

Claim:
A method for determining a delay time of a pre-catalytic converter lambda probe during operation of an arrangement with an internal combustion engine, the method comprising the steps of: supplying a difference between an output signal of the pre-catalytic converter lambda probe and a desired signal to a controller as an input signal; measuring an output signal of the controller, said output signal determining an air-fuel ratio of the exhaust gas to which the pre-catalytic converter lambda probe is exposed during the operation; determining a first time when a first output signal of the controller satisfies a first predetermined criterion; determining a second time following the first time when a second output signal of the pre-catalytic converter lambda probe satisfies a second predetermined criterion; determining a time difference between the second time and the first time, said time difference defining the delay time; and determining an actual air-fuel ratio of the exhaust gas to which the pre-catalytic converter lambda probe is exposed by determining the output signal of the controller at a time computed by adding the delay time to the second time.