Dual-Filter Gas Sensor Control for Noise Suppression
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Solution Overview
Problem
Increasing the sampling rate of digital signals in sensor control apparatuses for gas sensors leads to an increase in noise components, compromising the accuracy of gas detection and oxygen pumping control.
Innovation Solution
Incorporating a dual-filter system within the sensor control apparatus, which includes an analog-to-digital conversion section, a supply control value computation section, and digital-to-analog conversion sections, along with a multiplexer to classify signals by frequency, thereby attenuating noise components and ensuring accurate feedback control and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sampling rate of digital signals is increased to meet the demand for quicker response in gas detection, then the response speed is improved, but the noise component (differential noise) produced by digital PID control increases
Solution Approach 1:
The patent divides the control signal processing into two separate filtering stages: a first filter section that processes the supply control value for pump current, and a second filter section that processes the detection signal. This segmentation allows each filter to be optimized for its specific purpose - the first filter suppresses noise in control signals while the second filter processes detection signals with appropriate noise characteristics, thereby maintaining signal accuracy even at higher sampling rates.
Solution Approach 2:
The patent introduces filter sections as intermediary components between the digital PID control and the gas sensor. These filter sections act as mediators that process and condition the digital signals before they are used for control or detection purposes, effectively suppressing differential noise while preserving the essential signal information needed for accurate gas detection and control.
2Volume of moving object
If a digital control section is used instead of an analog circuit to meet the demand for miniaturization, then the device size is reduced, but noise components in digital signals increase
Solution Approach 1:
The patent replaces analog filtering circuits with digital filter sections that operate within the digital control section. This substitution maintains the miniaturized digital architecture while effectively suppressing noise components through digital signal processing techniques, thereby preserving signal accuracy without requiring additional analog circuitry.
Solution Approach 2:
The digital filter sections serve as intermediary processing stages within the digital control section, mediating between the raw digital signals from the sensor and the processed signals used for control and detection. These filter sections effectively remove noise components while preserving signal integrity, enabling accurate operation of the miniaturized digital control system.
3Productivity
If the sampling rate is increased to improve response speed, then quicker gas detection is achieved, but the differential noise in control signals increases
Solution Approach 1:
The patent segments the signal processing into distinct filtering stages: the first filter section processes control signals to suppress differential noise, while the second filter section processes detection signals. This segmentation enables the system to operate at higher sampling rates for improved detection speed while effectively managing noise in control signals through dedicated filtering.
Solution Approach 2:
The filter sections act as intermediary components that process digital signals at high sampling rates while suppressing differential noise. These filters enable the system to achieve quicker gas detection responses without allowing noise components to interfere with control accuracy or detection precision.
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 dual-filter system effectively suppresses noise components even at higher sampling rates, improving the accuracy of gas detection and maintaining proper oxygen pumping control, enhancing the overall performance of the gas detection system.
Implementation Method 1
the oxygen pump cell of the gas sensor is a cell which performs pumping in or pumping out of oxygen in accordance with pump current
Implementation Method 2
the detection cell of the gas sensor is a cell which produces an electromotive force corresponding to a particular component contained in object gas
Data Source
AI summary
A sensor control apparatus of a gas detection system includes a digital computation section having a PID computation section, a first filter section, and a second filter section as functional sections. The first filter section digitally extracts a DAC control signal (first filter signal) from a digital signal representing a supply control current Tip computed by the PID computation section. The DAC control signal is a digital signal which represents the supply control current Tip for pump current and in which noise components superimposed as a result of digital computation in the PID computation section have been attenuated.