Gas Burner Mixing Ratio Control via Fan Speed Adaptation

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Solution Overview

Problem

Existing gas burner operation methods maintain a constant gas/air mixing ratio over the entire modulation range, which can lead to suboptimal combustion efficiency and emissions, especially as fan speed varies, without adequately addressing sensor function integrity.

Innovation Solution

A method that dynamically adjusts the gas/air mixing ratio based on fan speed, with sensor function verification and compensation for sensor gain shifts, allowing variation only under specific operating conditions to ensure stable combustion and reduced emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the gas/air mixing ratio is kept constant over the entire modulation range, then the control system is simple, but combustion efficiency and emissions are suboptimal

Engineering Contradiction:
Improvecontrol system complexityVSAvoidcombustion efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements dynamic adjustment of the gas/air mixing ratio based on fan speed variations. The control system continuously monitors fan speed and automatically modifies the mixing ratio to maintain optimal combustion conditions across different operating points, transforming the static mixing ratio approach into a dynamic adaptation strategy that responds to real-time operational changes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the mixing ratio parameter as a function of fan speed. By establishing a predetermined relationship between fan speed and optimal mixing ratio, the system adjusts the gas/air mixing ratio parameter dynamically, allowing combustion optimization without requiring complex real-time calculations or additional sensors.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the mixing ratio is dynamically adjusted based on fan speed, then combustion efficiency improves, but sensor function integrity must be verified

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidsensor function integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary verification of sensor function integrity before enabling dynamic mixing ratio adjustment. The control system checks whether the actual sensor output deviates from the predetermined relationship beyond a threshold value, and only allows dynamic adjustment when sensor reliability is confirmed. This preliminary check prevents unreliable sensor data from causing incorrect mixing ratio adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback verification by continuously monitoring the relationship between fan speed and sensor output. The control system compares actual sensor readings against expected values based on the predetermined relationship, and uses this feedback to determine whether to maintain or block dynamic adjustment mode, ensuring ongoing sensor reliability.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If sensor gain shifts occur, then measurement accuracy deteriorates, but compensation mechanisms can restore functionality

Engineering Contradiction:
Improvesensor output accuracyVSAvoidsensor gain stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent prepares compensation strategies in advance for potential sensor gain shifts. By establishing a predetermined relationship between fan speed and sensor output, the system creates a reference framework that can detect and compensate for gain variations. The threshold-based verification mechanism is pre-configured to identify when compensation is needed.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent compensates for sensor gain shifts by adjusting the offset value in the predetermined relationship. When sensor gain drift is detected beyond the threshold, the control system modifies the relationship parameters to compensate for the drift, effectively restoring measurement accuracy without requiring physical sensor replacement or recalibration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2685169B1Method for operating a gas burner
Publication Date: 2018.10.24 HONEYWELL TECHNOLOGIES SARL
  • EP2685169B1 patent drawingFigure 1

AI summary

Method for operating a gas burner (10), wherein during burner-on phases a gas/air mixture having a defined mixing ratio of gas and air is provided to a burner chamber (11) of the gas burner (10) for combusting the gas/air mixture within the burner chamber (11), wherein the gas/air mixture is provided by mixing an air flow sucked in by a fan (14) with a gas flow, and wherein the defined mixing ratio of the gas/air mixture is controlled by comparing an actual value of a signal provided by an electrical or electronic sensor (23) coupled to a gas duct (16) with a nominal value for the signal provided by the electrical or electronic sensor (23) and by generating a control variable for a gas valve (17) assigned to the gas duct (16) on basis of the control deviation between the actual value and the nominal value. During burner-on phases the function of the electrical or electronic sensor (23) becomes checked by generating an input variable for an actuator (21) of the gas valve (17), by operating the gas valve (17) on basis of the input variable for the actuator (21) and by comparing an actual output signal provided by the electrical or electronic sensor (23) in response to this operation of the gas valve (17) with a nominal output signal expected in response to this operation of the gas valve (17).