Particle Filter Diagnostics Using Temperature-Standardized Pressure Vectors
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Solution Overview
Problem
Current methods for diagnosing internal combustion engine exhaust gas systems with particle filters are limited in their ability to comprehensively detect flow anomalies, often leading to incorrect diagnoses such as filter breakage or clogging, which can result in unnecessary filter replacements.
Innovation Solution
A method that determines and compares temperature-standardized value vectors representing absolute pressures upstream and downstream of the particle filter, differential pressure, and exhaust gas volume flow to generate reference characteristics, allowing for the differentiation of flow anomalies like leakage, clogging, or filter breakage by evaluating deviations from these characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential pressure across the particle filter is measured and compared to a differential pressure of a constant throttle location, then the influence of exhaust gas flow non-stationarity is considered, but the diagnosis cannot distinguish between filter loading and other flow anomalies such as leakage or clogging
Solution Approach 1:
The diagnostic method segments the analysis by comparing multiple pressure values (upstream absolute pressure, downstream absolute pressure, and differential pressure) against corresponding reference characteristics derived from exhaustive testing. This segmentation allows identification of specific flow anomaly types by analyzing which pressure deviations occur, thereby distinguishing between filter loading, leakage, and clogging scenarios that a single differential pressure measurement cannot differentiate.
2Loss of information
If a single differential pressure measurement is used, then the measurement system is simple, but the diagnostic capability is insufficient to differentiate between various flow anomalies
Solution Approach 1:
The measurement system achieves multi-functionality by using three pressure sensors (upstream absolute pressure sensor, downstream absolute pressure sensor, and differential pressure sensor) that simultaneously provide data for multiple diagnostic purposes: determining filter loading status, detecting leakage anomalies, identifying clogging conditions, and distinguishing between different flow anomaly types. This universal approach replaces the need for multiple separate measurement systems.
3Measurement precision
If temperature dependence is not eliminated from pressure values, then the measurement system is simpler, but the diagnostic accuracy varies with temperature changes
Solution Approach 1:
The method transforms pressure measurements by applying temperature compensation to convert actual pressure values into temperature-standardized pressure values. This parameter change eliminates the influence of temperature variations on pressure readings, allowing consistent comparison against reference characteristics obtained under standardized temperature conditions, thereby maintaining diagnostic accuracy across different operating temperatures.
4Reliability
If a large number of value vectors are collected over a long period, then the diagnostic reliability is improved, but the response time for anomaly detection increases
Solution Approach 1:
The method performs preliminary action by pre-determining reference characteristics through exhaustive testing covering the entire expected operating range of the exhaust gas system. These reference characteristics, which include the relationships between pressure values, volume flow, and temperature under various conditions (including potential anomalies), are stored beforehand. During operation, the system only needs to compare current measurements against these pre-established references, enabling rapid anomaly detection without requiring extensive real-time data collection.
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 enhances diagnostic reliability by eliminating temperature dependence and differentiating between various flow anomalies, reducing the likelihood of incorrect diagnoses and unnecessary filter changes, thereby improving the accuracy and effectiveness of anomaly detection.
Implementation Method 1
The determined values for the absolute pressure upstream and downstream of the particle filter, and the differential pressure at least of the first set of value vectors are transformed to temperature-standardized values so that temperature dependence is eliminated, or nearly eliminated
Data Source
AI summary
In a method for the diagnostics of an internal combustion engine exhaust gas system that includes a particle filter, first and second sets of value vectors are determined, each including associated values for absolute pressure upstream and downstream of the particle filter, a differential pressure determined from the values of the absolute pressure, an exhaust gas volume flow through the particle filter, and a temperature of the exhaust gas volume flow. After a temperature-standardization of the pressure values, characteristics for dependence of the pressure values are generated from temperature-standardized values of the first set of value vectors and possibly stored as reference characteristics. By comparing temperature-standardized values for the absolute pressure on the inlet and outlet sides of the particle filter and the differential pressure of the second set of value vectors with reference characteristics, flow anomalies can be determined in the exhaust gas system.