Patent ID: 9704306
Date: 2017-07-11
CPC Classifications: F02D,G07C

Claim:
1. A method for monitoring the dynamics of a gas sensor of an internal combustion engine, wherein the gas sensor exhibits a low-pass behavior as a function of at least one of geometry, measurement principle, aging, and contamination, the method comprising: performing a dynamics diagnosis upon a change in a gas state variable measured by the gas sensor, on the basis of a comparison between a modeled and a measured signal; wherein the measured signal is an actual value of an output signal of the gas sensor and the modeled signal is a model value, and wherein the parameters of the low-pass behavior are determined in direction-dependent fashion by minimizing direction-dependent error signals which are created by high-pass filtering and logical combination with direction-dependent saturation characteristic curves, the direction-dependent error signals being calculated by comparing the modeled and the measured signal for a rising and a falling signal component, wherein the gas state variable for diagnosing the dynamics of the gas sensor is an air/fuel ratio of an air/fuel mixture delivered to the internal combustion engine, and wherein the air/fuel ratio is varied by a positive excitation that periodically varies the air/fuel ratio one of (i) by way of small step-like changes in an injection quantity, or (ii) by way of an oscillating control circuit.