Temperature-Compensated Gas Sensor Circuit for Accurate Detection
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Solution Overview
Problem
Existing gas sensors fail to accurately cancel the influence of gases not being measured due to varying environmental temperatures, leading to measurement errors.
Innovation Solution
A gas sensor design incorporating series-connected thermistors, a temperature sensor, a variable resistor, and a control circuit that adjusts the resistance value of the variable resistor based on temperature detection signals to compensate for environmental temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correction resistor is connected in parallel to one of the thermistors to cancel measurement error, then measurement accuracy is improved, but the ability to correctly cancel influence of unmeasured gas deteriorates due to environmental temperature variations
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed correction resistor with a variable resistor whose resistance value can be dynamically adjusted based on environmental temperature. The control circuit changes the resistance value of the variable resistor according to temperature detection signals, allowing the correction mechanism to adapt to different temperature conditions and maintain measurement accuracy across varying environments.
Solution Approach 2:
The patent implements parameter changes by modifying the resistance value of the correction resistor based on temperature parameters. The control circuit detects environmental temperature and adjusts the resistance value of the variable resistor accordingly, changing the electrical parameter to match the thermal conditions and ensure correct cancellation of unmeasured gas influence at different temperatures.
2Measurement precision
If a fixed correction resistor is used to compensate for unmeasured gas influence, then measurement error is reduced under specific conditions, but measurement accuracy deteriorates when environmental temperature changes
Solution Approach 1:
The patent applies feedback by implementing a closed-loop control system where the control circuit continuously monitors environmental temperature through the temperature sensor and adjusts the resistance value of the variable resistor accordingly. This feedback mechanism ensures that the correction resistor always has the appropriate resistance value for the current temperature condition, maintaining measurement accuracy despite temperature variations.
Solution Approach 2:
The system performs self-service by automatically adjusting its own correction parameters based on environmental conditions. The control circuit autonomously detects temperature changes and modifies the resistance value of the variable resistor without external intervention, allowing the gas sensor to self-adapt to different thermal environments and maintain accurate measurements.
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 design enables accurate measurement of gas concentrations by correcting for environmental temperature influences, reducing measurement errors caused by gases not being measured.
Implementation Method 1
a gas sensor part (11) including first and second thermistors (Rd1, Rd2) connected in series
Implementation Method 2
a temperature sensor part (12) configured to generate a temperature detection signal
Data Source
AI summary
Disclosed herein is a gas sensor that includes a gas sensor part including first and second thermistors connected in series, a temperature sensor part configured to generate a temperature detection signal, a variable resistor connected in parallel to the first thermistor, and a control circuit configured to change a resistance value of the variable resistor based on the temperature detection signal.