Diagnosing Y-Config Catalytic Converters Without Probes
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Solution Overview
Problem
Current methods for diagnosing catalytic converters in exhaust gas cleaning systems with a Y configuration are unable to determine the oxygen storage capacity of individual catalytic converters without an exhaust gas probe between them and the main catalytic converter, leading to diagnostic limitations and increased costs.
Innovation Solution
A method that uses signals from existing exhaust gas probes to determine the oxygen storage capacity of individual catalytic converters by calculating the difference between the oxygen storage capacities of the first individual catalytic converter and the main catalytic converter, allowing for diagnosis without the need for an additional probe between them, and reducing measurement errors through stoichiometric and oscillating lambda value variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an exhaust gas probe is installed between each individual catalytic converter and the main catalytic converter to enable diagnosis, then the measurement precision of oxygen storage capacity is improved, but the device complexity and cost increase
Solution Approach 1:
The patent uses the exhaust gas probe positioned between the first individual catalytic converter and the main catalytic converter as an intermediary measurement point. By measuring oxygen storage capacity of the first converter and using this data to calculate the second converter's capacity (through subtraction from the total), the system avoids needing a direct probe on the second converter while maintaining measurement accuracy
Solution Approach 2:
The patent creates a virtual measurement copy by calculating the oxygen storage capacity of the second individual catalytic converter through mathematical subtraction from the total system capacity. This calculated value serves as a proxy for direct measurement, eliminating the need for additional physical sensing hardware
2Reliability
If five exhaust gas probes are installed to diagnose all three catalytic converters in Y configuration, then the diagnosis completeness is improved, but the manufacturing cost increases
Solution Approach 1:
The exhaust gas probe positioned between the first individual catalytic converter and the main catalytic converter serves multiple functions: it measures oxygen storage capacity for the first converter, provides data for calculating the second converter's capacity, and contributes to overall system diagnostics. This multi-functional use reduces the total probe count from five to four while maintaining complete diagnosis capability
Solution Approach 2:
The patent changes the measurement approach from direct physical measurement at multiple points to a combination of direct measurement and calculated parameter derivation. By measuring the first converter's oxygen storage capacity and calculating the second converter's capacity through parameter subtraction, the system achieves complete diagnostics with fewer sensors
Data Source
AI summary
The invention is distinguished by a method and a corresponding device for diagnosis of an individual catalytic converter of an exhaust gas purification unit assigned to an internal combustion engine in the Y configuration, despite the lack of exhaust gas probe between the individual catalytic converter and a main catalytic converter. The diagnosis proceeds on the basis of signals from the exhaust gas probes belonging to the exhaust gas purification unit. On the basis of these signals, the oxygen storage capacity of the individual catalytic converter is determined despite the lack of exhaust gas probe between the individual catalytic converter and the main catalytic converter.