Ionization Electrode Combustion Control for Hydrogen Fuel

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Solution Overview

Problem

Existing combustion apparatuses struggle to maintain a stable mixing ratio of air and gaseous fuels, especially when hydrogen gas is introduced, leading to incomplete or unclean combustion and potential safety hazards, as they often require recalibration and rely on optical filters that can fail.

Innovation Solution

An optical sensor records unfiltered signals from a combustion chamber, including various spectral lines to mitigate humidity and moisture effects, allowing for control of the mixing ratio without optical filters, and optionally uses an ionization electrode to enhance signal processing and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical filters are used to detect spectral lines, then measurement precision is improved, but reliability deteriorates due to filter failure risk

Engineering Contradiction:
Improvespectral line detection precisionVSAvoidoptical filter reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent removes optical filters from the detection system entirely, extracting the problematic component that caused reliability issues. The system achieves spectral line detection without filters by using an ionization electrode to measure ionization current, which inherently provides spectral information without requiring physical optical filters that can fail.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical filter system with an electrical measurement system. Instead of using physical optical filters to select spectral lines, the system uses an ionization electrode to detect ionization current at different voltages, where each voltage corresponds to ionization of specific molecules or radicals, thereby substituting mechanical optical filtering with electrical field-based detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If gaseous fuel formulation changes (e.g., adding hydrogen), then adaptability is improved, but manufacturing precision deteriorates due to incomplete combustion

Engineering Contradiction:
Improvefuel formulation adaptabilityVSAvoidcombustion completeness
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system that continuously monitors ionization current at multiple voltages and adjusts combustion parameters accordingly. The controller uses the ionization current signals to detect changes in fuel composition and adjusts air-fuel ratio or other combustion parameters to maintain complete and clean combustion, regardless of fuel formulation changes including hydrogen addition.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the detection parameter from fixed optical filtering to variable voltage-dependent ionization current measurement. By measuring ionization current at different voltages, the system can identify specific molecular species (CO, H2O, H2, O2, N2) and use this information to adjust combustion parameters, enabling adaptation to different fuel formulations while maintaining combustion precision.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If ionization electrode is used instead of optical filters, then device complexity is reduced, but measurement precision may deteriorate

Engineering Contradiction:
Improveoptical system complexityVSAvoidspectral detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The ionization electrode serves multiple functions simultaneously: it detects the presence of flame, identifies fuel composition through voltage-dependent ionization current characteristics, and provides feedback for combustion control. This multi-functionality replaces what previously required separate optical filters, detectors, and control systems, reducing overall device complexity while maintaining measurement precision through the inherent spectral information in ionization currents.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables precise control of the mixing ratio, reducing adverse influences from humidity and moisture, and maintaining stable combustion conditions without the risk of optical filter failure, thus ensuring clean and efficient combustion.

Implementation Method 1

a flame within a combustion chamber also emits visible and ultraviolet light. Those signals can be recorded by a sensor arranged at or near the combustion chamber.

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Light

Implementation Method 2

an ionisation electrode is arranged within a flame zone inside a combustion chamber. The ionisation electrode produces a signal indicative of an electric conductivity within the flame zone.

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP4283196B1Controlling a mixing ratio
Publication Date: 2024.10.30 SIEMENS AG
  • EP4283196B1 patent drawingFigure 1
  • EP4283196B1 patent drawingFigure 2
  • EP4283196B1 patent drawingFigure 3

AI summary

Controlling a mixing ratio. A method of controlling a mixing ratio of combustion air and a gaseous fuel comprising more than twenty percent of hydrogen gas, wherein the combustion air and the gaseous fuel are combusted together in a combustion chamber (2), the method comprising the steps: a first optical sensor (8) recording a first raw signal directly originating from a flame (1) inside the combustion chamber (2), producing a first sensor signal from the first raw signal, and sending the first sensor signal to a controller (14); the controller (14) determining a first signal strength of the first sensor signal; after recording the first raw signal, changing a supply of combustion air and/or of gaseous fuel to the combustion chamber (2); the at least one first optical sensor (8) recording a second raw signal directly originating from the flame (1) inside the combustion chamber (2).