Three-Way Catalyst Oxygen Storage Estimation Using Exhaust Gas Sensors
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Solution Overview
Problem
Current methods for estimating the oxygen storage capacity of a three-way catalyst in internal combustion engines are inaccurate, leading to suboptimal fuel strategies and emission reduction, and require additional hardware, which increases costs.
Innovation Solution
An engine system with a control logic sequence that estimates oxygen storage capacity using measured inputs such as CO, H2, and O2 concentrations, and accounts for sensor aging effects, allowing for real-time monitoring and adjustment of fuel strategies without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods of estimating oxygen storage capacity using fuel cut off during deceleration are used, then the estimation can be obtained, but the accuracy of estimation is insufficient to allow for aggressive fuel strategy
Solution Approach 1:
The patent changes the measurement parameters by using multiple exhaust gas concentration measurements ([CO], [H2], [O2]) at different locations (catalyst inlet and outlet) rather than relying on a single fuel cut-off event. This multi-parameter approach fundamentally alters the estimation methodology to achieve higher accuracy.
Solution Approach 2:
The patent implements a feedback mechanism by continuously monitoring exhaust gas concentrations at both catalyst inlet and outlet, then using this feedback information to dynamically estimate oxygen storage capacity. This continuous feedback loop enables more accurate and timely estimation compared to periodic fuel cut-off methods.
2Measurement precision
If additional hardware is added to improve oxygen storage capacity estimation accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing exhaust gas concentration sensors serve multiple functions: they not only monitor emissions but also provide data for oxygen storage capacity estimation. This multi-functionality eliminates the need for dedicated estimation hardware while improving measurement accuracy.
Solution Approach 2:
The system uses its own existing sensors and processing capabilities to perform the oxygen storage capacity estimation without requiring external or additional measurement devices. The engine control module leverages available data to self-determine catalyst health status.
Data Source
AI summary
An engine system for a vehicle includes an internal combustion engine having an exhaust gas outlet, an exhaust system having a three-way catalyst and a switch-type post oxygen sensor, and an engine control module that controls the engine system. The engine control module includes a first control logic for estimating a three-way catalyst oxygen storage capacity based on a plurality of measured inputs, a second control logic for estimating aging effects of the switch-type post oxygen sensor, and a third control logic that calculates a filtered estimated three-way catalyst oxygen storage capacity for the three-way catalyst.