Optical Combustion Control via UV Radical Detection
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Solution Overview
Problem
Existing combustion control systems are invasive and unable to accurately regulate the mixing ratio of combustion air to fuel gas, particularly when the fuel gas composition changes, such as with the addition of hydrogen, leading to poor combustion and safety issues.
Innovation Solution
A non-invasive method using optical sensors and filters to selectively measure ultraviolet radiation from combustion emissions, specifically OH* radicals, to adjust the combustion air supply and achieve precise control of the lambda value, allowing for continuous operation and maintenance-free operation across varying fuel gas compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ionization electrode is used to measure electrical conductivity for regulating the mixing ratio, then the mixing ratio can be controlled, but the measurement becomes invasive and influences the combustion process
Solution Approach 1:
The patent introduces an intermediary substance (seed material containing phosphorus) that facilitates the measurement process without directly interfering with combustion. The seed material absorbs combustion products and enables optical detection of the mixing ratio through phosphorescence intensity, acting as a mediator between the combustion process and the measurement system.
Solution Approach 2:
The patent replaces the electrical measurement system (ionization electrode measuring electrical conductivity) with an optical measurement system. Instead of using electrical fields to detect mixing ratio, the system uses optical detection of phosphorescence intensity from the seed material, substituting mechanical/electrical measurement with optical measurement to avoid combustion interference.
2Measurement precision
If control devices are designed for a specific fuel gas composition, then they can regulate combustion accurately for that composition, but they cannot adapt when fuel gas changes without maintenance and readjustment
Solution Approach 1:
The patent creates a universal control system that can handle multiple fuel gas compositions (natural gas, biogas, hydrogen, and their mixtures) without requiring specific device configurations. The optical measurement method combined with seed material works across different fuel types, making the system multi-functional and adaptable to various combustion scenarios.
Solution Approach 2:
The patent enables the control system to adapt to changing fuel gas compositions by continuously monitoring phosphorescence intensity and dynamically adjusting combustion parameters (air-to-fuel ratio, ignition timing). The system detects changes in combustion characteristics through optical measurement and automatically compensates by modifying operational parameters, maintaining accurate combustion control despite fuel variability.
3Reliability
If optical sensors are used to measure ultraviolet radiation from combustion emissions, then non-invasive measurement is achieved, but selective filtering is required to isolate specific radical emissions
Solution Approach 1:
The patent applies local quality by using specific optical filters that are selective for particular phosphorescence wavelengths emitted by the phosphorus-containing seed material. Instead of attempting to detect all emissions, the system focuses on specific local wavelength ranges that carry the mixing ratio information, using targeted optical filtering rather than broad-spectrum detection.
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 method provides precise and reliable control of the combustion process, ensuring efficient and safe combustion even with high hydrogen content fuel gases, with automatic calibration to maintain accuracy and adapt to changing fuel gas compositions, enhancing operational reliability and service life.
Implementation Method 1
it has been shown that during combustion not only light in the visible range, namely the so-called thermal radiation, is emitted, but also in the ultraviolet range, in which there is only little thermal radiation, emission radiation from various excited by the chemical reactions groups of molecules is generated. Of particular note are the CH* radicals and the OH* radicals
Implementation Method 2
This radiation can be selectively filtered for both types of radicals and non-invasively observed with optical sensors (ultraviolet-sensitive semiconductor sensors)
Implementation Method 3
at least one first optical filter and at least one first optical sensor are present on or in the housing, the first optical sensor being arranged in this way is that light from the combustion chamber can reach the first sensor via the first optical filter
Data Source
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AI summary
The invention relates to a method for influencing or controlling the mixing ratio (lambda) of combustion air and a gaseous fuel, which are burned together in a combustion chamber (7), wherein light generated during combustion is selectively filtered and converted into an electrical sensor signal by at least one first optical sensor (10), the strength of which is evaluated in an electronic module, wherein a supply of combustion air to the combustion chamber (7) is changed and the resulting change in the strength of the sensor signal is evaluated, and wherein the supply of combustion air is adjusted or controlled depending on the result of the evaluation.The invention also relates to a corresponding device for influencing or controlling the mixing ratio (lambda) of combustion air and a gaseous fuel, which are supplied to a combustion chamber (7) in a housing (1) via a gas supply line (2) and a combustion air supply line (3), wherein a pump (4) is arranged in the combustion air supply line (3) and at least one first optical filter (9) and at least one first optical sensor (10) are provided on or in the housing (1), wherein the first optical sensor (10) is arranged such that light from the combustion chamber (7) can pass through the first optical filter (9) to the sensor (10). The described control system functions robustly for fuel gases of different compositions, in particular also those containing hydrogen, or for pure hydrogen as the fuel gas.