Patent ID: 9714623
Date: 2017-07-25
CPC Classifications: F02D

Claim:
1. A method for regulating an air/fuel ratio of an internal combustion engine, comprising: determining a composition of an exhaust gas of the internal combustion engine by detecting an actual probe signal of the exhaust gas by means of an exhaust gas probe, and by applying a characteristic curve or a calculation rule expressing the exhaust gas composition as a function of the actual probe signal using a regulating device, wherein the determined exhaust gas composition has a lambda value, comparing the lambda value of the determined exhaust gas composition with a setpoint value or a threshold value, influencing the air/fuel ratio fed to the internal combustion engine, when the lambda value of the determined exhaust gas composition reaches or exceeds the setpoint value or the threshold value, defining a safety interval (ΔS) to take into account at least one interference variable which effects a deviation of the lambda value of the determined exhaust gas composition from a lambda value of an exact exhaust gas composition by acting on the actual probe signal, wherein the safety interval (ΔS) ensures that the lambda value of the exact exhaust gas composition is lower than a target lambda value, and applying the safety interval (ΔS) to the characteristic curve, to the calculation rule or to the actual probe signal or defining the setpoint value or threshold value for the exhaust gas composition as a function of the target lambda value and the safety interval, evaluating a current accuracy level of at least one of the at least one interference variable and a current influence of the at least one interference variable on the probe signal, and defining the safety interval (ΔS), which is conditioned by the at least one interference variable, as a function of the evaluation.