Gas Sensor Voltage Measurement Correction
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Solution Overview
Problem
The integration of leads for voltage measurement and heater energization in gas sensors reduces the accuracy of voltage measurement between electrodes.
Innovation Solution
A gas sensor design that includes a voltage acquisition section, a heater power supply, an external common lead serving as both an electric circuit for voltage acquisition and heater power supply, and a correction section to derive and correct for voltage drops based on heater current and temperature, improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If leads are integrated to serve both voltage measurement and heater energization, then the number of leads is reduced, but the accuracy of voltage measurement decreases
Solution Approach 1:
The patent implements a feedback mechanism where the voltage drop in the common lead is measured and used to correct the electrode voltage measurement. The control unit calculates the voltage drop based on heater current and lead resistance, then subtracts this from the measured voltage to obtain the corrected electrode voltage, thereby maintaining measurement accuracy despite lead integration
Solution Approach 2:
The patent introduces a correction mechanism as an intermediary between the integrated lead system and the voltage measurement. By calculating and compensating for the voltage drop in the common lead, the system mediates the conflict between lead integration and measurement accuracy, allowing both functions to coexist effectively
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 configuration enhances the accuracy of voltage measurement between electrodes by accounting for voltage drops due to heater current and temperature variations, thereby improving the overall measurement precision.
Implementation Method 1
a heater that adjusts the sensor element to a temperature at which the solid electrolyte layers are activated
Implementation Method 2
an element body having an oxygen-ion-conductive solid electrolyte layer
Implementation Method 3
a gas sensor that detects the concentration of a specific gas, such as NOx, in a measurement-object gas
Data Source
AI summary
A gas sensor includes a sensor element including an element body, a first electrode, a second electrode, and a heater; a voltage acquisition section that acquires a voltage between the first electrode and the second electrode; a heater power supply; an external common lead that serves as both at least part of an electric circuit used to acquire the voltage by providing electrical continuity between the first electrode and the voltage acquisition section and at least part of an electric circuit used to supply an electric power from the heater power supply to the heater and that is disposed outside the sensor element; and a correction section that derives a value of a voltage drop in the external common lead in accordance with a heater current and that corrects the voltage acquired by the voltage acquisition section in accordance with the derived value of the voltage drop.