Wide-Band Lambda Probe Offset Correction Using Regression Signals
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Solution Overview
Problem
Conventional methods for operating wide-band lambda probes require additional sensors and filters to compensate for interference, and direct comparisons of pump current or lambda values can be inefficient.
Innovation Solution
A method using only signals from the lambda probe itself, employing a regression line calculated from measured value pairs to implicitly compensate for interference, allowing for the identification and correction of pump current or lambda offsets without additional sensors or filters, utilizing the method of least squares for low memory and computing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct comparison of pump current or lambda values is used, then the method is simple, but measurement precision deteriorates due to interference
Solution Approach 1:
The patent introduces a regression line as an intermediary element that mediates between the measured pump current/voltage signals and the final lambda value determination. Instead of directly comparing raw signals, the regression line serves as a reference model that accounts for interference and aging effects, allowing accurate offset identification while maintaining method simplicity
Solution Approach 2:
The patent implements a feedback mechanism where the regression line is continuously updated based on measured value pairs from the lambda probe. This feedback loop allows the system to adapt to changing conditions and maintain measurement precision without requiring additional sensors or complex filtering, as the regression line automatically compensates for interference
2Measurement precision
If additional sensors or filters are added to compensate for interference, then measurement precision improves, but device complexity increases
Solution Approach 1:
The lambda probe performs self-diagnosis and self-adjustment by using its own signals (pump current, pump voltage) to identify offsets through regression line analysis. The system is self-sufficient and does not require additional sensors or filters, as the regression line methodology inherently compensates for interference and aging effects using only the probe's inherent signals
Solution Approach 2:
The patent changes the approach from directly using raw sensor signals to using processed parameters (measured value pairs) that are fitted to a regression line. This parameter transformation allows the system to extract accurate lambda values while filtering out interference through the regression analysis, eliminating the need for additional physical filters or sensors
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances measuring accuracy by implicitly compensating for interference, reducing the need for additional filters and sensors, and enabling effective self-adjustment and diagnosis of wide-band lambda probes.
Implementation Method 1
a ceramic sensor element (112), in particular a sensor element having an electrochemical pump cell (116) and an electrochemical Nernst cell (216)
Implementation Method 2
the electrochemical pump cell (116) having an outer pump electrode (118) which is directly exposed to the exhaust gas and an inner pump electrode (118') which is situated in the cavity (130), and a first solid electrolyte (120) disposed between the outer pump electrode (118) and the inner pump electrode (118')
Implementation Method 3
the electrochemical Nernst cell (216) has a Nernst electrode (218), which is situated in the cavity (130), and a reference electrode (218'), which is situated in a reference gas chamber (204), and a second solid electrolyte (120') disposed between the Nernst electrode (218) and the reference electrode (218')
Data Source
AI summary
A method for operating a wide-band lambda probe. The method includes controlling the Nernst voltage to a predefined setpoint value by setting the pump voltage and/or the pump current, measuring the pump voltage and/or the pump current and/or the lambda value, forming measured value pairs based on measured measuring values of the pump voltage, the pump current and/or the lambda value, calculating a regression line based on the measured value pairs in order to approximate a predefined part of a reference characteristic curve of the pump voltage, and ascertaining a pump current offset and/or lambda offset based on the regression line.