Gas Sensor Control Device for Exhaust Diagnosis
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Solution Overview
Problem
Existing gas sensor control devices face challenges in maintaining high accuracy and frequent execution of deterioration diagnosis due to environmental factors like exhaust pressure, atmospheric pressure, and gas composition, which affect the diffusion rate of exhaust gases, leading to reduced diagnosis frequency and accuracy.
Innovation Solution
A gas sensor control device with a first cell for oxygen removal and a second cell for specific gas concentration measurement, including a control unit, determination value acquisition unit, diagnosis unit, and correction unit, which temporarily reduces oxygen removal capability, acquires determination values, and corrects output values or thresholds based on exhaust pressure, atmospheric pressure, and gas composition to reflect environmental factors, thereby improving diagnosis accuracy and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If environmental factors (exhaust pressure, atmospheric pressure, gas composition) are not corrected, then the device complexity is low, but the measurement precision of gas sensor deterioration diagnosis decreases
Solution Approach 1:
The patent applies parameter changes by introducing correction parameters based on environmental factors (exhaust pressure, atmospheric pressure, gas composition) to adjust the determination threshold or output values. This compensates for variations in diffusion rate caused by environmental conditions, thereby maintaining high measurement precision without requiring complex hardware modifications.
2Measurement precision
If deterioration diagnosis is performed only under specific conditions (exhaust temperature > predetermined temperature, excess air ratio > predetermined threshold), then the measurement precision is high, but the productivity of diagnosis execution frequency decreases
Solution Approach 1:
The patent changes the approach from condition-based diagnosis to correction-based diagnosis. By introducing environmental parameter corrections, the system can perform accurate deterioration diagnosis under a wider range of operating conditions, not limited to specific temperature and air ratio thresholds, thereby increasing diagnosis execution frequency while maintaining accuracy.
3Reliability
If the diffusion rate variation is not compensated, then the device complexity is low, but the reliability of deterioration diagnosis under varying conditions decreases
Solution Approach 1:
The patent compensates for diffusion rate variations by changing the determination threshold or output values based on environmental parameters. This software-based correction mechanism reliably accounts for diffusion rate changes without requiring complex hardware modifications, thereby maintaining high reliability under varying conditions.
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
The solution enhances the accuracy of gas sensor deterioration diagnosis by accounting for environmental factors, allowing for more frequent and accurate diagnosis, even under varying diffusion rates, thus improving the overall performance of the gas sensor control device.
Implementation Method 1
a first cell, which removes oxygen contained in an exhaust gas of an internal combustion engine of a vehicle
Implementation Method 2
a second cell, which outputs a current corresponding to a concentration of a specific gas contained in the exhaust gas
Implementation Method 3
The diffusion rate of the exhaust gas in the gas sensor affects the deterioration diagnosis result of the gas sensor. Furthermore, the diffusion rate of the exhaust gas in the gas sensor depends on the exhaust pressure, the atmospheric pressure, and the gas composition of the exhaust gas.
Data Source
AI summary
A control device performs deterioration diagnosis of a gas sensor including a pump cell and a sensor cell. The control device includes a control unit, a determination value acquisition unit, a diagnosis unit, and a correction unit. The control unit temporarily reduces the oxygen removal capability of the pump cell. The determination value acquisition unit acquires an output ratio of the sensor cell based on an output value of the sensor cell in a state where the oxygen removal capability of the pump cell is temporarily reduced. The diagnosis unit performs deterioration diagnosis of the gas sensor by comparing the output ratio with a determination threshold. The correction unit sets a correction coefficient based on an atmospheric pressure and an oxygen concentration, and also corrects the output ratio using the correction coefficient.