Flame Temperature Sensor Recalibration for Combustion Air Ratio Control
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Solution Overview
Problem
Existing hydrogen-powered heating appliances face challenges in accurately controlling the combustion air-fuel ratio due to sensor drift in flame temperature sensors, leading to unsafe operating conditions and requiring expensive modifications or indirect control methods that are not precise.
Innovation Solution
A method involving a flame temperature sensor to determine an operating point, heat the sensor, adjust the combustion air flow to match the detected temperature, and calculate the required change in air flow to verify and compensate for sensor drift, using a reference relationship to determine the combustion air ratio without structural changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flame temperature sensor is used to measure combustion air ratio, then measurement capability is provided, but sensor drift occurs leading to inaccurate measurements
Solution Approach 1:
The control system continuously monitors the flame temperature sensor signal and compares it against expected values. When drift is detected, the system automatically adjusts the combustion air ratio or triggers a recalibration sequence, using feedback to correct measurement errors and maintain accuracy over time
Solution Approach 2:
The system performs periodic preliminary checks and recalibrations of the flame temperature sensor before actual combustion control operations. This preliminary action prevents drift from affecting measurement accuracy and ensures the sensor remains calibrated to actual combustion conditions
2Measurement precision
If a lambda sensor is used to monitor sensor drift, then measurement accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The flame temperature sensor system performs self-diagnosis and self-correction by monitoring its own signal characteristics and automatically adjusting for drift conditions. This self-service capability eliminates the need for separate lambda sensors while maintaining measurement accuracy
Solution Approach 2:
The flame temperature sensor serves multiple functions: it measures combustion air ratio, monitors sensor drift, and triggers recalibration procedures. This multi-functionality replaces what would traditionally require separate dedicated sensors, reducing overall system complexity
3Ease of operation
If temperature measurement is used to control combustion air ratio, then control capability is achieved, but indirect control leads to unsafe operating conditions
Solution Approach 1:
The system uses real-time feedback from the flame temperature sensor to continuously adjust combustion air ratio, ensuring the mixture remains within safe operating limits. The feedback mechanism prevents indirect control issues by directly monitoring and responding to actual combustion conditions
Solution Approach 2:
The combustion control system dynamically adjusts the combustion air ratio based on real-time flame temperature measurements rather than relying on fixed indirect control parameters. This dynamic response ensures safe operating conditions are maintained under varying load and environmental 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
Enables accurate verification and compensation of the combustion air ratio, ensuring safe operation and precise control of hydrogen-powered heating devices without additional components or structural modifications.
Implementation Method 1
measuring the radiation emitted by the flame, especially UV radiation
Implementation Method 2
measuring the ionization current of the flame
Implementation Method 3
a conveying device for conveying a mixture of fuel and combustion air to a burner
Implementation Method 4
burn it and use the resulting heat to supply a building
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method for operating a heating appliance (1) is proposed, which includes a conveying device (2) for conveying a combustion mixture of fuel and combustion air to a burner (3) and a flame temperature sensor (13) for detecting a temperature (20). The method may include at least the following steps: a) detecting an operating point and associated operating parameters of the heating appliance (1), b) heating the flame temperature sensor (13), c) increasing the supplied mass flow of combustion air until the temperature (20) of the flame temperature sensor (13) corresponds to the temperature (20) detected in step a), and detecting the required change in the mass flow of combustion air to cool the flame temperature sensor (13) to the temperature (20) detected in step a), and d) determining a combustion air ratio (27) based on the change in the mass flow of combustion air detected in step c).The method enables the detection and compensation of a sensor drift of a flame temperature sensor (13) used for flame monitoring and a related third element of a determined combustion air ratio (27).