Vehicle Aftertreatment NOx Sensor Feedback for Catalyst Malfunction Detection
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Solution Overview
Problem
Aftertreatment systems in vehicles often fail to convert nitric oxides to nitrogen dioxides efficiently due to malfunctions, leading to incorrect reducing agent supply and inefficient reduction of harmful exhaust gases.
Innovation Solution
An aftertreatment system with upstream and downstream NOx sensors and a control unit that uses a model to estimate conversion ratios, allowing for real-time detection of malfunctions and appropriate responsive actions, including model updates or component diagnostics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aftertreatment systems are used without real-time monitoring, then the system structure remains simple, but the conversion efficiency of nitric oxides to nitrogen dioxides deteriorates due to undetected malfunctions
Solution Approach 1:
The patent implements a feedback mechanism by comparing the actual conversion ratio (measured by NOx sensors upstream and downstream of the oxidation catalyst) with the expected conversion ratio (calculated by a control unit using a model). This feedback loop enables real-time detection of malfunctions and triggers responsive actions to maintain reliable conversion efficiency.
Solution Approach 2:
The system performs self-diagnosis by automatically detecting malfunctions through sensor data comparison and executing responsive actions without external intervention. The control unit monitors the aftertreatment system's own performance and initiates corrective measures, enabling the system to service itself and maintain reliability.
2Productivity
If real-time malfunction detection is implemented using sensor comparison, then the operational efficiency improves, but the device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The control unit serves multiple functions: it calculates the expected conversion ratio using a model, compares it with actual sensor data, detects malfunctions, and initiates responsive actions. This multi-functionality consolidates complex operations into a single control unit, improving operational efficiency while managing system complexity.
Solution Approach 2:
The patent replaces complex mechanical monitoring systems with an electronic control system that uses software models and electronic sensors. The control unit uses computational methods to monitor and diagnose the aftertreatment system, substituting mechanical complexity with electronic and software-based solutions that improve operational efficiency.
3Measurement precision
If the model is updated in real-time based on sensor data, then the accuracy of reducing agent supply improves, but the risk of incorrect updates and system errors increases
Solution Approach 1:
The control unit is pre-programmed with a model representing expected conversion ratios under various operating conditions. This preliminary configuration provides a baseline for comparison, enabling accurate real-time monitoring without requiring complex real-time model development, thus improving measurement precision while maintaining system stability.
Solution Approach 2:
The system takes preliminary protective measures by establishing threshold criteria for model updates and implementing validation checks before applying updates. This prevents incorrect updates from compromising system stability, allowing the system to maintain high measurement precision while protecting against reliability issues.
4Ease of operation
If differentiated responsive actions are implemented based on malfunction severity, then the ease of operation improves, but the device complexity increases due to multiple action protocols
Solution Approach 1:
The system simplifies operation by changing the parameter of malfunction classification into discrete severity levels (first and second malfunction conditions). This parameterization enables straightforward decision-making logic in the control unit, making the system easier to operate while managing control logic complexity through structured parameter-based responses.
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
Enables rapid identification and correction of malfunctions, ensuring efficient conversion of nitric oxides to nitrogen dioxides and reducing agent supply, thereby improving the operational efficiency of the aftertreatment system.
Implementation Method 1
an oxidation catalyst which is arranged to convert nitric oxides to nitrogen dioxides
Data Source
Figure 1
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Figure 5
AI summary
The present inventive concept relates to an aftertreatment system for a vehicle, the aftertreatment system being connectable to an internal combustion engine, wherein the aftertreatment system comprises an oxidation catalyst, a first NOx sensor arranged upstream the oxidation catalyst, a second NOx sensor arranged downstream the oxidation catalyst, and a control unit comprising a processor device configured to determine a sensor based conversion ratio of nitric oxides to nitrogen dioxides by the oxidation catalyst from data received from first and second NOx sensor, obtain an estimated conversion ratio of nitric oxides to nitrogen dioxides by the oxidation catalyst from a model, and determine a malfunction condition of the aftertreatment system in response to the sensor based conversion ratio being different from the estimated conversion ratio, and perform a responsive action of the aftertreatment system based on the malfunction condition.