Gas-Adaptive Combustion Appliance Control for Variable Fuel Quality

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Solution Overview

Problem

Gas adaptive combustion appliances face challenges in maintaining stable and safe operation due to unpredictable changes in fuel gas quality, leading to start issues and inefficiencies, particularly in systems with multiple boilers connected in a cascade.

Innovation Solution

The method involves determining the Wobbe value of the fuel gas and controlling the combustion appliance based on this value to adjust the air-fuel mixture, using a data processing device to manage the fuel valve, throttle unit, and fan to ensure consistent operation and prevent ignition failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If gas adaptive combustion appliances use fixed control parameters for air-fuel mixture, then device complexity is reduced, but combustion stability deteriorates when fuel gas quality changes

Engineering Contradiction:
Improvecontrol system complexityVSAvoidcombustion stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control system dynamically adjusts air-fuel mixture parameters based on detected Wobbe value changes. The data processing device continuously monitors fuel gas quality and modifies control signals to the air supply device and fuel supply device, transforming a static control system into an adaptive dynamic one that maintains combustion stability despite fuel variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (air flow rate, fuel flow rate) based on detected Wobbe value variations. When fuel gas quality changes are detected, the control device adjusts these parameters to maintain optimal combustion conditions, effectively adapting to different fuel types without requiring complex hardware modifications.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If gas adaptive combustion appliances periodically calibrate combustion parameters, then combustion efficiency is improved, but loss of time increases due to calibration interruptions

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidcalibration interruption time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary detection of Wobbe value changes and proactively adjusts combustion parameters before significant efficiency degradation occurs. By continuously monitoring fuel gas quality and preemptively adapting air-fuel mixture ratios, the system avoids the need for frequent time-consuming calibration interruptions while maintaining high combustion efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system maintains continuous adaptation of combustion parameters based on ongoing Wobbe value monitoring. This continuous adjustment process eliminates gaps in optimal combustion performance that would occur during periodic calibration interruptions, ensuring uninterrupted efficient operation.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If multiple boilers are connected in cascade without Wobbe value coordination, then device complexity is reduced, but reliability deteriorates due to ignition failures when fuel gas quality changes

Engineering Contradiction:
Improvecascade system complexityVSAvoidignition reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The cascade system implements feedback mechanisms where each boiler's data processing device detects Wobbe value changes and communicates this information to other boilers in the cascade. This coordinated feedback approach ensures all boilers adapt their air-fuel mixture settings consistently, preventing ignition failures that would occur with uncoordinated independent operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system provides universal adaptation across all boilers in the cascade by sharing Wobbe value information. Each boiler uses the same adaptive control logic based on common fuel gas quality data, ensuring consistent reliable operation across the entire cascade system regardless of individual boiler status.

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 ensures stable and safe operation of combustion appliances by adapting to changes in fuel gas quality, preventing start issues and maintaining efficient combustion, even when the fuel gas characteristics vary.

Implementation Method 1

This ratio is measured with an oxygen sensor in the flue gas

Methodology Applied
Scientific EffectOxygen sensing:

Implementation Method 2

Gas adaptive combustion uses at least one sensor signal to adjust the air fuel mixture to maintain a preset value, such as an ionization signal

Methodology Applied
Scientific EffectFlame ionization: Ionisation

Implementation Method 3

a burner (7) for combusting an air and fuel mixture

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4600555A1Method for operating at least one, in particular gas adaptive, combustion appliance
Publication Date: 2025.08.13 BDR THERMEA GRP
  • EP4600555A1 patent drawingFigure 1
  • EP4600555A1 patent drawingFigure 2
  • EP4600555A1 patent drawingFigure 3

AI summary

The invention relates to a method for operating at least one, in particular gas adaptive, combustion appliance wherein the method comprises the following steps: determining at least one Wobbe value and controlling the combustion appliance dependent on the determined at least one Wobbe value.