Catalyst Estimator Oxygen Storage Control
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Solution Overview
Problem
Current catalytic converter systems face challenges in accurately controlling emissions and optimizing the air-to-fuel ratio (AFR) in gas engine systems, which affects both engine efficiency and regulatory compliance, due to limitations in monitoring and modeling catalyst performance.
Innovation Solution
A system comprising a processor that receives signals from oxygen and NOx sensors, utilizing a catalyst estimator with an Adaptive Extended Kalman Filter (AEKF) to modify a catalytic converter model, derive oxygen storage estimates, and setpoints, and adjust the AFR to control the catalytic converter system, thereby improving emissions control and engine efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catalytic converter system is used to control emissions, then emissions compliance is improved, but the complexity of the control system increases
Solution Approach 1:
The system implements feedback control by continuously monitoring oxygen storage capacity using upstream and downstream oxygen sensors, comparing the actual oxygen storage against a setpoint, and adjusting the air-to-fuel ratio accordingly. This closed-loop feedback mechanism enables precise emissions control while maintaining manageable system complexity through automated regulation.
Solution Approach 2:
The patent replaces complex mechanical monitoring and adjustment mechanisms with an electronic control system that uses sensors, a processor, and software algorithms (including an Adaptive Extended Kalman Filter) to monitor catalyst performance and adjust engine parameters. This substitution of mechanical systems with electronic control reduces overall system complexity while improving precision.
2Productivity
If the air-to-fuel ratio is controlled to optimize engine efficiency, then engine performance is improved, but emissions control precision deteriorates
Solution Approach 1:
The system dynamically adjusts the air-to-fuel ratio parameter based on real-time catalyst oxygen storage capacity measurements. By continuously modifying this critical parameter according to actual catalyst performance rather than using fixed ratios, the system simultaneously optimizes engine efficiency and maintains precise emissions control adaptability.
Solution Approach 2:
The control system transitions from static air-to-fuel ratio settings to dynamic adjustment based on real-time catalyst performance monitoring. The system continuously adapts the air-to-fuel ratio in response to changing oxygen storage capacity, enabling both optimal engine performance and precise emissions control under varying operating conditions.
3Reliability
If oxygen storage capacity is monitored to improve catalytic converter performance, then emissions control is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The system uses oxygen sensors positioned upstream and downstream of the catalytic converter as intermediary measurement devices. These sensors indirectly measure oxygen storage capacity by detecting oxygen concentration differences across the catalyst, transforming an difficult-to-measure internal catalyst property into accessible electrical signals that can be processed by the control system.
Solution Approach 2:
The patent replaces direct physical measurement of oxygen storage capacity with electronic sensing and computational estimation. Using the Adaptive Extended Kalman Filter algorithm, the system processes electrical signals from oxygen sensors to calculate oxygen storage capacity, substituting complex direct measurement with electronic detection and mathematical modeling.
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 solution enables precise control of the catalytic converter system, enhancing emissions compliance and engine performance by accurately estimating oxygen storage dynamics and adjusting the AFR based on real-time data, leading to improved catalytic converter system performance and diagnostic capabilities.
Implementation Method 1
The catalytic converter system receives the exhaust gases and substantially converts the exhaust gases into other types of gases permitted by regulations and restrictions
Implementation Method 2
The processor is configured to receive a first signal from a first oxygen sensor indicative of a first oxygen measurement
Implementation Method 3
The processor is also programmed to receive a third signal from a nitrogen oxide sensor indicative of NOx emissions of the catalytic converter system
Implementation Method 4
The processor is further configured to execute a catalyst estimator system, wherein the catalyst estimator system is configured to modify a catalytic converter model based in part on the third signal and to derive an oxygen storage estimate based on the first signal, the second signal, and the modified catalytic converter model
Data Source
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AI summary
A system 10 includes a controller 16 that has a processor configured to receive a first signal from a first oxygen sensor 30A indicative of a first oxygen measurement, wherein the first oxygen sensor is disposed upstream of a catalytic converter system 32; and to receive a second signal from a second oxygen sensor 30B indicative of a second oxygen measurement, wherein the second oxygen sensor is disposed downstream of the catalytic converter system 32; and to execute a catalyst estimator system 40, wherein the catalyst estimator system 44 is configured to derive an oxygen storage estimate based on the first signal, the second signal, and a catalytic converter model. The processor is configured to derive a system oxygen storage setpoint for the catalytic converter system based on the catalytic converter model and the oxygen storage estimate.