Gas Burner Air-Fuel Control Using Atmospheric Density Compensation
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Solution Overview
Problem
Existing gas burner appliances struggle with maintaining precise control over the mixing ratio of gas and air (λ-value) due to changes in air density, which affects burner load and heat demand, leading to inconsistent combustion quality.
Innovation Solution
A method and controller that determine atmospheric density based on ambient air pressure and temperature, adjusting fan speed and gas regulation valves to maintain a constant λ-value across varying burner loads, using sensors and electric coils to compensate for temperature offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fan speed is adjusted to match varying heat demand, then burner load adapts to different operating conditions, but air density changes cause inconsistent mixing ratio and combustion quality
Solution Approach 1:
The patent implements a feedback control system where a sensor detects the actual λ-value (mixing ratio) and feeds this information back to the controller. The controller compares the actual λ-value with the target λ-value and adjusts the gas valve opening accordingly to maintain the desired mixing ratio despite air density changes associated with varying fan speeds and heat demands.
Solution Approach 2:
The patent changes the control parameter from direct fan speed control to λ-value-based control. By measuring air density (which changes with temperature and pressure) and using this information to calculate and maintain a constant λ-value, the system compensates for air density variations and maintains consistent combustion quality across different operating conditions.
2Manufacturing precision
If pneumatic or electric gas regulation valve is used to maintain constant λ-value, then mixing ratio control is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex pneumatic control systems with an electrically actuated gas valve controlled by an electronic controller. This substitution simplifies the overall system by eliminating pneumatic components (such as pneumatic actuators and pressure regulation mechanisms) while achieving comparable or superior control precision through electronic sensing and actuation.
3Measurement precision
If ambient air pressure and temperature are measured to determine atmospheric density, then fan speed adjustment precision is improved, but measurement and control complexity increases
Solution Approach 1:
The patent makes the controller multi-functional by integrating both the λ-value control function and the atmospheric density measurement function into a single control unit. The controller not only adjusts the gas valve to maintain constant λ-value but also processes sensor inputs (temperature and pressure) to determine atmospheric density and adjust fan speed accordingly. This consolidation reduces overall system complexity despite the added measurement capabilities.
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
Enhances control quality by ensuring a consistent gas-to-air mixture ratio, improving combustion efficiency and stability across different operating conditions.
Implementation Method 1
Determine on basis of an ambient air pressure and on basis of an ambient air temperature the atmospheric density of the ambient air
Implementation Method 2
Determine on basis of an ambient air pressure and on basis of an ambient air temperature the atmospheric density of the ambient air
Implementation Method 3
The air flow flowing through the air duct is provided by fan in such a way that the fan speed of the fan depends on a nominal burner-load
Implementation Method 4
The pneumatic gas regulation valve uses a pressure difference between the gas pressure of the gas flow in the gas duct and a reference pressure
Implementation Method 5
The gas/air mixture is provided by a mixing device mixing an air flow provided by an air duct with a gas flow provided by a gas duct
Implementation Method 6
During burner-on-phases of the gas burner appliance, a gas/air mixture having a defined mixing ratio of gas and air is provided to a burner for combusting the gas/air mixture
Data Source
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AI summary
Method for operating a gas burner appliance by providing a flow of a gas/air mixture having a defined mixing ratio of gas and air or a defined A-value to a burner chamber (11) for combusting the gas/air mixture. Said gas/air mixture is provided by a mixing device (25) mixing an air flow with a gas flow. The air flow or the flow of the gas/air mixture is provided by a fan (14) in such a way that a fan speed of the fan depends on a nominal burner-load of the gas burner appliance (10). The fan speed range of the fan (14) defines a modulation range of the gas burner appliance. The defined mixing ratio of gas and air or said A-value of the gas/air mixture is controlled over the modulation range using a gas regulation valve (18) of a gas armature (17) in order to keep the defined mixing ratio or the defined A-value constant over the modulation range. The method comprises the following steps: Determine on basis of the nominal burner-load and on basis of the mixing ratio of gas and air of the gas/air mixture or the A-value of the gas/air mixture a nominal air mass flow in order to provide the nominal burner-load. Determine the ambient air pressure and the ambient air temperature of the ambient air. Determine on basis of the ambient air pressure and on basis of the ambient air temperature the atmospheric density of the ambient air. Determine on basis of the nominal air mass flow, on basis of the determined atmospheric density of the ambient air and on basis of a system resistance of the gas burner appliance the fan speed of the fan in order to provide the nominal burner-load. Figure 1