Selective EGR Fault Detection via Dual Flow Estimation
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Solution Overview
Problem
Internal combustion engines face challenges in maintaining the target mixture of exhaust, air, and fuel in the exhaust gas recirculation (EGR) system, leading to operational issues and the need for effective fault and leak detection within the EGR system.
Innovation Solution
A diagnostic system comprising a first and second exhaust gas flow rate estimation module and an EGR fault detection module, which estimate exhaust flow rates based on oxygen concentration and engine parameters to selectively indicate faults or leaks in the EGR system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If exhaust gas recirculation is implemented to reduce emissions, then environmental performance is improved, but the complexity of the system increases and requires sophisticated diagnostic capabilities
Solution Approach 1:
The diagnostic system is segmented into multiple independent estimation modules (first EGF estimation module using oxygen concentration, second EGF estimation module using engine parameters) that can independently assess different aspects of exhaust gas flow, making the complex diagnostic task manageable and modular
Solution Approach 2:
The patent introduces intermediary estimation modules that act as mediators between the complex EGR system and the diagnostic requirement. These modules translate complex system behavior into measurable parameters (exhaust gas flow rate estimates) that can be compared to detect faults
2Reliability
If the EGR system is monitored continuously to detect faults, then reliability is improved, but the computational load and processing requirements increase
Solution Approach 1:
The diagnostic system performs partial monitoring by focusing on specific critical parameters (exhaust gas flow rate) rather than continuously analyzing all possible system parameters. The system selectively activates diagnostic functions based on operating conditions, reducing unnecessary computational overhead while maintaining reliability
Solution Approach 2:
The patent creates a virtual model (copy) of the exhaust gas flow by estimating it through multiple independent calculation paths (oxygen concentration-based estimation and engine parameter-based estimation). This virtual copy allows fault detection without requiring direct physical sensors in the exhaust path, reducing computational and hardware complexity
3Measurement precision
If multiple estimation methods are used to improve diagnostic accuracy, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple independent estimation approaches (oxygen concentration measurement, engine speed, engine load) into a unified diagnostic framework. By combining these different measurement methods, the system achieves higher measurement precision for exhaust gas flow rate while sharing common processing infrastructure to manage complexity
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
The system effectively identifies EGR faults and leaks, ensuring the engine operates within the target mixture parameters, enhancing diagnostic capabilities and maintaining engine performance.
Implementation Method 1
The first EGF estimation module estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold
Data Source
AI summary
A system for a vehicle includes a first exhaust gas flow rate (EGF) estimation module, a second EGF estimation module, and an EGF fault detection module. The first EGF estimation module estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold. The second EGF estimation module estimates a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load. The EGF fault detection module selectively indicates a fault is present in an exhaust gas recirculation (EGR) system based on the first flow rate and the second flow rate.