Exhaust Gas Sensor Transverse Sensitivity Compensation
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Solution Overview
Problem
Existing methods for determining particle mass flow in exhaust gas systems of internal combustion engines using resistive particle sensors are hindered by strong transverse sensitivity to external variables, leading to inaccurate and slow signal changes, which complicates timely compensation and accurate measurement under dynamic operating conditions.
Innovation Solution
The measured and predicted signal changes of the particle sensor are corrected by accounting for influencing variables such as exhaust gas temperature, volume flow, and gaseous components, using methods like the gradient and trigger methods, allowing for precise determination of particle mass flow even during rapid dynamic changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If particle sensors are used to measure particle mass flow in exhaust gas, then particle accumulation can be detected through impedance changes, but the sensors exhibit strong transverse sensitivity to external variables such as temperature and exhaust gas speed, leading to measurement inaccuracies
Solution Approach 1:
The patent implements feedback by continuously monitoring the sensor signal and comparing it with expected values based on engine operating parameters. The system detects deviations caused by transverse sensitivities and compensates for them through signal processing, thereby maintaining measurement accuracy despite external influences.
Solution Approach 2:
The patent compensates for transverse sensitivities by adjusting the evaluation parameters based on actual operating conditions. By changing temperature, exhaust gas flow rate, and engine load parameters in the evaluation model, the system adapts to varying conditions and maintains accurate particle mass flow measurements despite environmental variations.
2Measurement precision
If particles are allowed to accumulate on the sensor to generate measurable signal changes, then detection sensitivity is improved, but the response time increases significantly, preventing timely compensation for transverse sensitivities
Solution Approach 1:
The patent applies preliminary action by pre-calculating expected sensor signals based on engine operating parameters and storing them for comparison. This allows the system to immediately compensate for transverse sensitivities without waiting for particle accumulation, thereby reducing measurement delay while maintaining detection sensitivity.
Solution Approach 2:
The patent introduces an intermediary evaluation model that translates engine operating parameters into expected sensor signals. This intermediary layer enables real-time compensation for transverse sensitivities by comparing actual signals with predicted values, eliminating the need to wait for particle accumulation before correcting measurement errors.
3Adaptability or versatility
If the particle sensor operates under dynamic operating conditions of the internal combustion engine, then the sensor can monitor varying exhaust gas compositions, but the sensor signal changes become too small to be reliably evaluated within the required time frame
Solution Approach 1:
The patent uses feedback by continuously comparing the small sensor signal changes with expected values calculated from engine operating parameters. This feedback mechanism amplifies the significance of small signal changes by referencing them against predicted values, enabling reliable detection even under dynamic operating conditions where absolute signal changes are minimal.
Solution Approach 2:
The patent compensates for small signal changes by dynamically adjusting evaluation parameters based on operating conditions. By changing temperature, flow rate, and load parameters in the evaluation model to match actual conditions, the system enhances the detectability of small signal changes that occur during dynamic operation.
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 and timely compensation for transverse sensitivities, improving the accuracy and speed of particle mass flow measurement, allowing for reliable assessment of operational conditions and detection of defective particle filters.
Implementation Method 1
If particles from the exhaust gas of an internal combustion engine accumulate on the particle sensor, this can lead to an analyzable change in the impedance of the particle sensor
Data Source
AI summary
The invention concerns a procedure to determine a mass of particles or a particle mass flow in an exhaust gas system of an internal combustion engine, whereby at least one resistive particle sensor is disposed in the exhaust gas system of the internal combustion engine. The measured signal change of the particle sensor is compared with a predicted signal change of the particle sensor ascertained from an engine model.If the measured signal change of the particle sensor and/or the predicted signal change of the particle sensor are corrected while taking into account the influencing variables on the transverse sensitivities of the particle sensor, it is possible when ascertaining the predicted signal change of the particle sensor that a compensation for the transverse sensibilities can result even during dynamic operating point changes of the internal combustion engine, which occur faster than the actuation of the particle sensor. This is the case because the correction can even be implemented for small predicted signal changes, such as those occurring during a currently transpiring operating point of the internal combustion engine. Because the predicted signal changes are ascertained from a set of characteristic curves of the engine model, these measurement intervals capable of being assigned to very short times and for that reason to individual operating points of the internal combustion engine can be determined with the very small predicted signal changes, which are required for this purpose.