Burner Ionization Spectrum Control for Thermoacoustic Stability
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Solution Overview
Problem
Existing burner control methods, particularly in mobile heating systems, face challenges due to varying environmental conditions and fuel compositions, leading to inconsistent combustion behavior, increased emissions, and disruptive thermoacoustic effects, which are difficult to address with existing spectral analysis methods.
Innovation Solution
A method for controlling a burner that utilizes an ionization signal to derive a control variable, adjusts the air-fuel mixture based on a frequency spectrum analysis, and corrects the setpoint to avoid thermoacoustic effects by shifting the air-fuel ratio to a different range, using a Fast Fourier Transform (FFT) and considering area ratios and standard deviations of the ionization signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral analysis methods are used to control combustion, then combustion stability can be improved, but the device complexity and measurement precision requirements increase significantly
Solution Approach 1:
The patent extracts only the essential information from the ionization signal by analyzing the area under spectral peaks rather than performing complete spectral analysis. This extraction approach maintains combustion stability control while significantly reducing computational complexity and measurement precision requirements.
Solution Approach 2:
Instead of analyzing the entire spectrum with high precision, the method applies partial action by focusing only on specific frequency ranges and using area integration rather than detailed peak analysis. This reduces the measurement precision requirements while maintaining effective combustion control.
2Measurement precision
If reference spectra are used for each burner type, then combustion monitoring accuracy improves, but the adaptability to system changes decreases
Solution Approach 1:
The patent creates a universal control method that works across different burner types and system configurations by using area-based spectral analysis rather than type-specific reference spectra. This single approach adapts to system changes while maintaining monitoring accuracy.
Solution Approach 2:
The method changes the evaluation parameter from fixed reference spectrum comparison to dynamic area integration that automatically adapts to system variations. This allows the system to maintain accuracy despite burner type differences, aging, and operational changes.
3Loss of information
If complete spectral analysis is performed, then combustion behavior assessment improves, but interference from external signals increases the complexity
Solution Approach 1:
The patent converts the harmful effect of external interference signals into a beneficial filtering mechanism by using area integration. The interference signals, which typically appear as distinct frequency components, contribute minimally to the total area under the combustion-related peaks, allowing natural filtering without complex processing.
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 provides reliable and simple control of combustion, effectively reducing emissions and noise by anticipating and adjusting to disturbances before they become audible, ensuring clean and quiet operation.
Implementation Method 1
ionization electrodes, which utilize the ionization effect of a flame
Implementation Method 2
the ionization signals are subjected to a Fourier transform and the resulting spectra are evaluated
Implementation Method 3
the thermal energy generated by burning an air-fuel mixture
Implementation Method 4
the thermal energy generated by burning an air-fuel mixture is transferred via a heat exchanger to room air and/or a liquid
Data Source
Figure 1~2b
Figure 3a~5
AI summary
The invention relates to a method for controlling a burner (1) which is supplied with an air-fuel mixture. A control variable is determined on the basis of an ionization signal, wherein the air-fuel mixture is adjusted as a function of the control variable and a desired value. A spectrum is obtained from the ionization signal, from which spectrum a measure of a surface area is determined. The desired value is adjusted as a function of the measure for the surface area. The invention further relates to a burner arrangement having a burner (1).