Catalytic Converter Oxygen Fill Regulation via Front Lambda Probe
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Solution Overview
Problem
Current engine control systems for three-way catalytic converters are slow to detect deviations from the optimal lambda (air/fuel ratio) range, leading to delayed fuel correction and increased tailpipe emissions due to the reliance on step-change lambda probes after the catalytic converter, which react late to impending departures from the conversion window.
Innovation Solution
A method that determines the aging state of the catalytic converter and uses model parameters to regulate the oxygen fill level earlier, allowing for prompt correction of the air/fuel mixture by processing signals from an exhaust gas probe before the catalytic converter, thereby preventing departures from the conversion window and improving emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a step-change lambda probe after the catalytic converter is used for regulation, then the catalytic converter can be operated in the conversion window, but the detection of deviations from optimal lambda range is delayed
Solution Approach 1:
The patent applies preliminary action by using a front lambda probe to detect deviations from the optimal lambda range before the exhaust gas reaches the catalytic converter. This allows the control system to initiate fuel correction in advance, preventing the catalytic converter from operating outside the conversion window rather than reacting after deviations occur.
Solution Approach 2:
The patent introduces an intermediary measurement approach by utilizing the front lambda probe as an early warning system. This intermediary detection point provides advance information about lambda deviations, enabling the control system to act proactively before the rear lambda probe would detect the same deviations after they have already affected catalytic converter performance.
2Reliability
If reliance is placed on rear lambda probe signals, then catalytic converter operation can be monitored, but fuel correction is delayed and emissions increase
Solution Approach 1:
The system performs preliminary detection of lambda deviations using the front lambda probe, allowing fuel correction to be initiated before the deviations propagate through the catalytic converter. This preventive approach reduces harmful emissions by maintaining optimal combustion conditions rather than correcting after emissions have already increased.
Solution Approach 2:
The patent implements a dual-feedback system using both front and rear lambda probes. The front probe provides early feedback for preventive correction, while the rear probe provides confirmation feedback. This layered feedback mechanism ensures rapid response to deviations while minimizing emissions by acting at the earliest possible moment.
3Device complexity
If conventional lambda regulation is used, then the system structure is simple, but the response to dynamic engine load changes is slow
Solution Approach 1:
The front lambda probe enables preliminary detection of lambda deviations that occur during dynamic engine load changes. This early detection allows the control system to respond immediately to load changes rather than waiting for the rear probe to detect deviations after they have propagated through the exhaust system, significantly improving response speed.
Solution Approach 2:
The regulation system is segmented into two functional parts: a front lambda probe for early detection and preventive control, and a rear lambda probe for confirmation and verification. This segmentation allows the system to maintain simple overall structure while achieving fast response through the distributed measurement points.
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 enables earlier recognition and prevention of departures from the conversion window, reducing emissions and meeting stricter regulatory requirements with improved accuracy and robustness, especially during dynamic engine load and speed changes.
Implementation Method 1
the oxygen content of the exhaust gas before the three-way catalytic converter is measured using a front exhaust gas probe disposed there
Implementation Method 2
The aforesaid pollutant components can be converted by using a three-way catalytic converter
Implementation Method 3
Because of the oxygen storage capability of the three-way catalytic converter, a lambda=1 condition can still exist for several seconds downstream from the three-way catalytic converter
Data Source
AI summary
A method is presented for regulating a filling of an exhaust gas component reservoir of a catalytic converter in the exhaust of an internal combustion engine. Using a first catalytic converter model, an actual fill level of the exhaust gas component reservoir is ascertained. An aging state of the catalytic converter is determined; and a set of model parameters of the first catalytic converter model is allocated to the aging state; the individual model parameters being ascertained by interpolation from basic values of model parameters, the basic values having been determined for at least two different aging states of a catalytic converter of identical design.