Flame Sensing Controller Using Flicker Criteria for Oil Burners
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Solution Overview
Problem
Legacy fuel oil burners designed for fossil fuels struggle to detect flames from renewable fuels, such as biodiesel, due to differences in chemical composition and flame properties, leading to inaccurate detection when using lower light thresholds.
Innovation Solution
Implementing a fuel oil burner controller with secondary flame sensing criteria, including relative light and flicker-related criteria, to reliably detect flames by comparing light samples against multiple thresholds and evaluating them based on average, maximum, minimum, or consecutive values, ensuring accurate detection of both fossil and renewable fuel flames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lower light thresholds are used to detect renewable fuel flames, then detection sensitivity for renewable fuels is improved, but false positive detection increases due to inaccurate flame identification
Solution Approach 1:
The flame detection process is segmented into multiple independent criteria: primary light threshold detection, secondary flicker detection, and tertiary duration validation. Each criterion acts as a separate filter that must be satisfied independently, preventing false positives while maintaining sensitivity for renewable fuel flames.
Solution Approach 2:
The system dynamically adjusts detection parameters based on fuel type. For renewable fuels, the system uses lower light thresholds combined with flicker rate analysis and duration requirements. For fossil fuels, higher thresholds are used. This parameter adaptation allows accurate detection across different fuel types without increasing false positives.
2Reliability
If multiple secondary sensing criteria are implemented, then flame detection reliability is improved, but device complexity increases
Solution Approach 1:
The existing light sensor is made multi-functional by having it perform both primary flame detection and secondary flicker detection. The same sensor data is analyzed for multiple characteristics (light level, flicker rate, duration) without adding separate sensing components, thereby improving reliability while minimizing complexity increase.
Solution Approach 2:
The system implements feedback through continuous monitoring and validation of flame characteristics. The controller continuously analyzes light sensor data against multiple criteria and adjusts detection decisions based on consistent patterns, ensuring reliable flame identification while using computational logic rather than additional hardware.
3Adaptability or versatility
If legacy burner designs are used for renewable fuels, then system compatibility is maintained, but detection accuracy deteriorates due to chemical composition differences
Solution Approach 1:
The detection system is made dynamic by adapting thresholds and criteria based on detected fuel type characteristics. The controller analyzes flame properties (light level, flicker rate, duration) and adjusts detection parameters accordingly, allowing legacy burners to accurately detect both fossil fuel and renewable fuel flames without hardware modifications.
Solution Approach 2:
The system changes detection parameters based on fuel chemical composition characteristics. Renewable fuels produce different flame signatures (lower light levels, different flicker rates) compared to fossil fuels. The controller adjusts thresholds and validation criteria to match the expected flame characteristics of the specific fuel type, maintaining high detection accuracy across different fuels.
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 the reliability of flame detection in fuel oil burners for both fossil and renewable fuels by using secondary criteria, preventing false positives and negatives, and ensuring consistent operation across different fuel types.
Implementation Method 1
A flame sensor 160 generates a flame sense signal that is indicative of whether a flame is present within the combustion chamber. Flame sense signals may be related to an amount of ultraviolet, visible, or infrared light that is present within the combustion chamber
Data Source
AI summary
Methods, systems, and circuitries are provided for detecting flame in a fuel oil burner. In one example, a method includes receiving a series of one or more light samples, each indicative of a level of light. When the fuel oil burner is operating in the flame expected mode, the method includes determining whether the values of the one or more of the light samples exceed a flame threshold; determining whether the values of the one or more of the light samples meet secondary criteria; determining that a flame is present when the values of the one or more light samples exceed the flame threshold and meet the secondary criteria; and determining that a flame is not present when the values of the one or more light samples are below the flame threshold or do not meet the secondary criteria.