Exhaust Gas Probe Calibration via Plateau Phase Detection
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Solution Overview
Problem
Current methods for calibrating exhaust gas probes in internal combustion engines are not precise enough to effectively manage air/fuel ratios, leading to inefficiencies in pollutant emission reduction and conversion in catalytic converters.
Innovation Solution
A method and device that detect plateau phases in the measured signal of exhaust gas probes after jumps in air/fuel ratios, allowing for the adjustment of allocation rules and control parameters to accurately assign air/fuel ratios, thereby simplifying and enhancing the calibration process without the need for a second probe downstream of the catalytic converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a second binary lambda probe is arranged downstream of the exhaust catalytic converter for calibration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention extracts and utilizes the plateau phase phenomenon that naturally occurs in the measured signal of the single exhaust gas probe during lambda transitions. By detecting and analyzing this plateau phase, the calibration function previously requiring a second downstream probe is achieved using only the single upstream probe, thereby reducing device complexity while maintaining calibration precision
Solution Approach 2:
The exhaust gas probe calibrates itself by utilizing characteristics of its own measured signal (the plateau phase during lambda transitions). The single probe serves both as the measurement device and the calibration reference, eliminating the need for a separate calibration probe downstream of the catalytic converter
2Measurement precision
If complex calibration methods are used to improve accuracy, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The calibration process is simplified by making the system self-calibrating through automatic detection of plateau phases in the measured signal. The control device automatically identifies plateau phases during lambda transitions and uses them for calibration without requiring complex manual procedures or additional hardware, thereby improving ease of operation while maintaining precision
Solution Approach 2:
The invention changes the approach from using complex multi-probe signal processing to utilizing a specific temporal characteristic (plateau phase duration and value) of the measured signal. This parameter-based calibration method simplifies the calibration process while achieving accurate air/fuel ratio measurements
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
This approach enables precise calibration of exhaust gas probes, improving the accuracy of air/fuel ratio management, reducing pollutant emissions, and optimizing the operation of internal combustion engines by utilizing the characteristics of plateau phases to set stoichiometric ratios.
Implementation Method 1
following a jump from a preset rich air/fuel ratio in the combustion chamber of the respective cylinder to a preset lean air/fuel ratio, a plateau phase which occurs thereafter in the measured signal is detected
Data Source
AI summary
A plateau phase of a test signal of an exhaust gas probe located in a catalytic converter is detected following a jump from a preset rich air/fuel ratio in a combustion chamber of one cylinder to a preset lean air/fuel ratio, the plateau phase being obtained following the jump, and the duration is determined as a storage period. A plateau phase of the test signal, which is obtained following a jump from a preset lean air/fuel ratio to a preset rich air/fuel ratio, is detected following the jump, and the duration of the plateau phase is determined as an evacuation period. An allocation rule for assigning the test signal to a detected air/fuel ratio is adjusted according to the storage period and the evacuation period. To calibrate the exhaust gas probe, the allocation rule is adapted according to a plateau value of the test signal during the plateau phase.