Gas Boiler Fuel Mixture Control via Thermal Property Detection
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Solution Overview
Problem
Existing gas boiler systems struggle to automatically adjust the fuel-oxidizer mixture in response to changes in fuel composition, leading to deviations in the regulated mixture and incorrect control, especially due to wear or aging of components and the increasing frequency of fuel composition changes, such as the admixture of excess hydrogen in the gas network.
Innovation Solution
A gas heater equipped with sensors to detect thermal properties of the fuel, such as thermal conductivity, density, and speed of sound, which transmit data to a control unit to determine the fuel composition. This control unit adjusts the fuel-oxidizer mixture by selecting the appropriate ionization current reference value and characteristic curve based on the detected composition, allowing for automatic calibration and optimal mixture adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed characteristic curve or function is stored in the control unit for determining the target ionization current, then the control system is simple and easy to operate, but it cannot adapt to changes in fuel composition leading to incorrect mixture regulation
Solution Approach 1:
The control unit is pre-programmed with algorithms that automatically detect fuel composition changes by monitoring ionization current deviations and trigger recalibration procedures. This preliminary automation eliminates the need for manual intervention while adapting to changing fuel conditions, resolving the contradiction between adaptability and system complexity.
Solution Approach 2:
The system performs self-calibration by automatically comparing measured ionization currents against stored reference values, detecting deviations caused by fuel composition changes, and adjusting the characteristic curve accordingly without requiring external manual recalibration. This self-service capability enables continuous adaptation while maintaining operational simplicity.
2Extent of automation
If manual intervention by specialist personnel is required to change the characteristic curve, then the system remains stable, but it cannot respond automatically to fuel composition changes and requires specialized knowledge for operation
Solution Approach 1:
The system continuously monitors the ionization current and compares it against the target value derived from the stored characteristic curve. When deviations exceed a threshold indicating fuel composition changes, the feedback mechanism automatically triggers a recalibration sequence, enabling responsive adaptation without manual intervention while maintaining ease of operation through automated decision-making.
Solution Approach 2:
The manual mechanical process of specialist personnel accessing and modifying stored characteristic curves is replaced by an automated electronic system that uses algorithms to detect fuel composition changes and automatically update the control parameters. This substitution eliminates the need for specialized knowledge while maintaining system stability through programmed logic.
3Reliability
If the system is periodically calibrated by enriching the fuel/oxidizer mixture above stoichiometric mixing, then wear and aging effects can be compensated, but the calibration becomes incorrect when fuel composition has changed
Solution Approach 1:
The calibration process is transformed from a static periodic procedure to a dynamic adaptive process. The system continuously adjusts the ionization current reference value based on real-time detection of fuel composition changes, ensuring that calibration remains accurate even as fuel composition varies. This dynamic approach maintains both reliability for compensating wear and precision for the ionization current reference value.
Solution Approach 2:
Before performing calibration procedures, the system first detects and identifies fuel composition changes by monitoring ionization current characteristics. This preliminary detection ensures that calibration is performed with the correct fuel composition context, preventing incorrect reference value determination while maintaining the ability to compensate for wear and aging effects.
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 precise and automatic adjustment of the fuel-oxidizer mixture, ensuring accurate control of the ionization current, even with changes in fuel composition, and accounts for wear or aging of components, maintaining optimal performance independently of fuel type or composition fluctuations.
Implementation Method 1
A sensor (3) arranged in or on the fuel line (102) for detecting a thermal property of the fuel flowing through the fuel line (102)
Implementation Method 2
The thermal conductivity, the thermal conductivity, the density or the speed of sound in the fuel or of the fuel can be detected as the thermal property detected by the at least one sensor (3)
Implementation Method 3
The thermal conductivity, the thermal conductivity, the density or the speed of sound in the fuel or of the fuel can be detected as the thermal property detected by the at least one sensor (3)
Implementation Method 4
The mixer (101) is designed to generate a fuel-oxidant mixture from a fuel flowing through the fuel line (102) to the mixer (101) and an oxidizer flowing through the oxidizer line (103) to the mixer (101)
Implementation Method 5
A current ionization current (actual ionization current) flowing over a flame in the burner of the gas boiler is measured
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a gas boiler (100) with a mixer (101), a fuel line (102) leading to the mixer (101), and an oxidizer line (103) leading to the mixer (101), wherein the mixer (101) is configured to produce a fuel-oxidizer mixture from fuel flowing through the fuel line (102) to the mixer (101) and oxidizer flowing through the oxidizer line (103) to the mixer (101), wherein the gas boiler (100) has a control unit (9) and at least one sensor arranged in or on the fuel line (102) for detecting a thermal property of the fuel flowing through the fuel line (102), which is connected to the control unit (9) via a signal system and configured to detect the thermal property of the fuel flowing through the fuel line (102) and transmit it to the control unit (9), wherein the control unit (9) is configured is,to determine the composition of the fuel from the recorded thermal properties of the fuel.