Residual Oxygen Sensor Offset Compensation
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Solution Overview
Problem
Existing methods for determining the air-to-fuel ratio in exhaust gases using residual oxygen sensors struggle with accurately compensating for signal offsets, leading to inefficiencies and higher emissions.
Innovation Solution
A method and device that detect and compensate for signal offsets in residual oxygen sensors by measuring residual oxygen content both upstream and downstream of a catalytic converter, determining actual air-to-fuel ratios, and applying correction values based on detected deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset compensation methods are used to correct sensor signals, then measurement precision is improved, but device complexity increases due to requiring multiple sensors and iterative correction processes
Solution Approach 1:
The patent divides the measurement system into two separate sensor positions: upstream and downstream of the catalytic converter. Each sensor independently measures residual oxygen content, and their signals are processed separately through iterative offset compensation. This segmentation allows the system to isolate and correct measurement errors at different stages, improving overall precision while managing complexity through modular signal processing.
Solution Approach 2:
The patent implements a feedback mechanism where the downstream sensor's measurement is used to determine an offset value that is then applied to correct the upstream sensor's signal. This iterative feedback process continues until convergence is achieved, ensuring high measurement precision. The feedback loop systematically reduces measurement errors without requiring complete system redesign.
2Reliability
If iterative correction processes are applied to sensor signals, then reliability is improved, but productivity decreases due to multiple measurement and calculation steps
Solution Approach 1:
The patent performs preliminary measurements using both upstream and downstream sensors simultaneously to establish baseline data. The offset calculation is prepared in advance by comparing initial readings, and the correction process is initiated before final control decisions are made. This preliminary action reduces the time critical corrections need to take, improving productivity while maintaining reliability through pre-validated measurement data.
Solution Approach 2:
The iterative correction process operates continuously without interrupting the exhaust gas measurement function. Both sensors take measurements concurrently, and the offset compensation calculations are performed in parallel with ongoing engine operation. This continuous operation ensures reliability through constant monitoring while maintaining productivity by avoiding process interruptions.
Data Source
AI summary
Device and method for correcting an offset in a signal of a first sensor for determining a residual oxygen content in an exhaust gas. A first actual ratio of air and fuel being determined as a function of a first residual oxygen content, a second actual ratio of air and fuel being determined as a function of a second residual oxygen content, a first offset of a first actual ratio relative to a reference ratio being determined for the first actual ratio when the second actual ratio is greater than the reference ratio, a second offset of a first actual ratio relative to the reference ratio being determined for the first actual ratio when the second actual ratio is smaller than the reference ratio, and a deviation being detected between the first offset and the second offset.