Ionization Signal Gradient Control for Gas Burner Air Ratio
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Solution Overview
Problem
Existing methods for adjusting the fuel gas/air mixture in combustible gas-operated burners often result in harmful combustion states leading to increased pollutant emissions, particularly carbon monoxide and nitrogen oxides, due to the necessity of starting or operating with stoichiometric or slightly sub-stoichiometric conditions.
Innovation Solution
A method that continuously measures the ionization signal and forms a gradient during changes in the air ratio, ending leaning when the gradient exceeds a certain threshold, and then enriches the fuel gas-air mixture to prevent harmful combustion states, using the gradient as an indicator for optimal air ratio adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel gas-air mixture is adjusted to stoichiometric or slightly sub-stoichiometric combustion to achieve complete combustion, then combustion efficiency is improved, but pollutant emissions (carbon monoxide and nitrogen oxide) increase
Solution Approach 1:
The patent applies feedback control by continuously measuring the ionization signal during the leaning process and using this information to detect when the flame is about to lift off. The control system adjusts the air ratio based on the measured ionization signal and its gradient, creating a closed-loop control that prevents harmful combustion states while maintaining optimal combustion efficiency.
Solution Approach 2:
The patent uses preliminary action by detecting the gradient of the ionization signal to predict when the flame will lift off before it actually happens. By monitoring the rate of change of the ionization signal, the system takes preventive action to stop the leaning process and enrich the mixture before harmful sub-stoichiometric combustion occurs, thus avoiding pollutant emissions.
2Object-generated harmful factors
If the fuel gas-air mixture is made leaner to reduce pollutant emissions, then environmental impact is improved, but combustion stability deteriorates and flame lift-off occurs
Solution Approach 1:
The system continuously monitors the ionization signal and its gradient, using this feedback to detect the approaching flame lift-off condition. When the gradient exceeds a threshold, the control system immediately enriches the mixture to restore combustion stability, preventing flame extinction while maintaining lean operation for reduced emissions.
Solution Approach 2:
The patent replaces traditional mechanical or temperature-based combustion monitoring with electrical ionization signal measurement. By using the ionization signal and its gradient as indicators, the system can detect combustion stability changes electrically rather than mechanically or thermally, enabling more precise and responsive control.
3Measurement precision
If traditional calibration methods are used to adjust the air ratio, then the burner must be temporarily operated with high pollutant emissions, but the adjustment accuracy is achieved
Solution Approach 1:
The patent applies preliminary action by using the gradient of the ionization signal to predict the optimal air ratio point before actually reaching it. This allows the system to identify the stoichiometric point and subsequent lean operation limits without temporarily operating in harmful combustion states, as the gradient method provides advance warning of flame lift-off conditions.
Solution Approach 2:
The calibration process uses continuous feedback from the ionization signal measurement during the leaning process. The system adjusts the air ratio while monitoring the ionization signal and stops precisely when the gradient indicates approaching flame lift-off, achieving accurate calibration without the need for temporary high-emission operation required by traditional methods.
4Ease of operation
If the flame is extinguished and restarted to achieve proper mixture ratio, then the air ratio can be adjusted, but temporary increases in emissions occur and continuous operation is interrupted
Solution Approach 1:
The patent ensures continuous operation by using the ionization signal gradient to predict flame lift-off before it occurs. The control system enriches the mixture proactively based on the gradient threshold, preventing flame extinction entirely. This maintains continuous combustion while achieving proper mixture ratio adjustment, eliminating the need for flame extinguishing and restarting.
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 approach reduces pollutant emissions by preventing harmful combustion states and allows for continuous operation without temporary increases in emissions associated with flame extinguishing and restarting, thereby improving burner control and reducing environmental impact.
Implementation Method 1
measuring the ionization voltage or the ionization current at a monitoring electrode
Data Source
Figure 1
Figure 2
AI summary
The setting process for the burner (1) is monitored by an ionization electrode (3), the signal of which may be measured directly or indirectly. During operation, the mixture is weakened and the ionization signal is continuously measured, A signal gradient is formed. If this is exceeded, the weakening of the mixture is ended and the mixtures setting is thus defined.