Catalytic Converter Oxygen Storage Capacity Determination
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Solution Overview
Problem
Current engine control systems react with delay to departures from the conversion window in three-way catalytic converters due to the inability to accurately measure or model the average oxygen fill level, leading to elevated tailpipe emissions.
Innovation Solution
A method to determine the actual maximum storage capacity of the catalytic converter, allowing for more precise regulation of the modeled fill level and compensation for measurement inaccuracies, enabling earlier detection of impending departures from the conversion window and prompt correction of the air/fuel mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the average oxygen fill level is modeled by calculation, then the fill level can be determined without direct measurement, but measurement inaccuracies and model uncertainties lead to delayed detection of departures from the conversion window
Solution Approach 1:
The patent determines the actual maximum storage capacity of the catalytic converter in advance during specific operating conditions (coasting phases with fuel shutoff). This pre-determined capacity value is then used to improve the accuracy of the fill level model during normal operation, allowing for earlier and more accurate detection of impending departures from the conversion window, thereby reducing the response delay.
2Reliability
If the maximum storage capacity is determined during coasting phases with fuel shutoff, then the actual maximum capacity can be ascertained under reliable conditions, but this requires additional operating condition monitoring and control
Solution Approach 1:
The control system utilizes existing coasting phases with fuel shutoff that naturally occur during vehicle operation (e.g., when the driver releases the accelerator). During these self-occurring conditions, the system automatically determines the maximum storage capacity without requiring additional external intervention or complex dedicated testing procedures. The system monitors operating parameters and performs the determination when appropriate conditions are met.
3Ease of operation
If the modeled fill level is regulated using a predetermined maximum storage capacity, then the regulation can be simplified, but inaccuracies in the predetermined value lead to suboptimal emission control
Solution Approach 1:
The patent replaces the predetermined maximum storage capacity parameter with an actual maximum capacity value that is dynamically determined based on real operating conditions. This parameter change allows the regulation system to maintain its simplicity while significantly improving accuracy, as the actual capacity reflects the true state of the catalytic converter rather than relying on fixed manufacturer specifications or theoretical values.
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 approach reduces emissions, meets stricter regulatory requirements, and extends the lifespan of the catalytic converter by allowing for timely adjustments to maintain optimal operating conditions.
Implementation Method 1
Because of the oxygen storage capacity of the three-way catalytic converter, lambda=1 can still exist after the three-way catalytic converter for several seconds after a rich or lean lambda has been established before the three-way catalytic converter.
Implementation Method 2
the oxygen content of the exhaust gas before the three-way catalytic converter is measured using an input-side exhaust-gas probe disposed there
Data Source
AI summary
A method and a control device for regulating a modeled fill level of an exhaust gas component reservoir of a catalytic converter of an internal combustion engine. Regulation of the modeled fill level is accomplished using a system model. An actual maximum storage capacity of the catalytic converter for the exhaust gas component is ascertained during operation of the internal combustion engine and is taken into consideration in regulating the modeled fill level.