Oxygen Sensor Calibration Using Dual-Range Deviation Detection
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Solution Overview
Problem
The accuracy of oxygen concentration detection by oxygen sensors in internal combustion engines is compromised due to variations in sensor output characteristics and deterioration over time, leading to fluctuations and noise during fuel cut operations, which complicates the computation of correction coefficients and affects the calibration of oxygen sensor output values with oxygen concentration.
Innovation Solution
An oxygen sensor control apparatus that computes a correction coefficient earlier by determining a representative value during fuel cut periods and using multiple ranges to judge deviations, allowing for timely recalibration of the oxygen sensor output values with respect to oxygen concentration, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correction coefficient is computed only after a predetermined number of fuel cut operations when the oxygen sensor output deviates from a reference range, then the detection accuracy is maintained during normal operation, but the recalibration period becomes excessively long when the sensor is replaced with a new one
Solution Approach 1:
The patent applies preliminary action by computing a preliminary correction coefficient during the first fuel cut operation when the sensor output deviates from the reference range, rather than waiting for a predetermined number of operations. This preliminary coefficient enables immediate recalibration, significantly reducing the recalibration period when a new sensor is installed while maintaining detection accuracy through subsequent updates
2Productivity
If the correction coefficient is computed during each fuel cut operation when output deviation occurs, then the recalibration is performed timely, but the computational load and system complexity increase
Solution Approach 1:
The patent applies partial action by computing the correction coefficient selectively during fuel cut operations only when the sensor output deviates from the reference range, rather than continuously or at every operation. This conditional computation approach achieves timely recalibration while minimizing unnecessary computational load and system complexity
3Measurement precision
If the correction coefficient is updated frequently based on output deviations, then the detection accuracy is improved, but the stability of the correction coefficient decreases
Solution Approach 1:
The patent applies periodic action by updating the correction coefficient at specific intervals during fuel cut operations when deviation conditions are met, rather than continuously or excessively frequently. This periodic update strategy maintains detection accuracy while ensuring the stability of the correction coefficient by allowing sufficient operation between updates
Data Source
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AI summary
In an oxygen sensor control apparatus, after start of fuel cut, the weighted average Ipd of corrected values obtained by multiplying the output value of a mounted oxygen sensor by a correction coefficient Kp is obtained as a representative value Ipe, representing the corrected values in the fuel cut period (S19). In the case where the number of times the representative value Ipe is continuously judged not to fall outside a second range (S21: NO) and to fall outside a first range (S23: YES) reaches 10 (a first number of times) (S26: YES), a new correction coefficient Kp is computed (S27). In the case where the number of times the representative value Ipe is continuously judged to fall outside the second range (S21: YES) reaches 4 (a second number of times smaller than the first number of times) (S29: YES), a new correction coefficient Kp is computed (S30).