Silicon Nitride Hot Surface Igniter for Low-Flow Gas Re-Ignition
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Solution Overview
Problem
Gas cooktops with spark igniters face issues such as damage to electronic components due to high electromotive force and annoyance from audible clicking sounds, while hot surface igniters struggle with structural strength and rapid ignition times, and existing systems fail to reliably re-ignite cooking gas at lower gas flow rates, not meeting industry standards for ignition and re-ignition times.
Innovation Solution
A hot surface igniter with a ceramic body and embedded conductive ink circuit that reaches high temperatures quickly and efficiently, designed to operate at lower gas flow rates, and integrated with a control system for coordinated gas supply and igniter energization, ensuring reliable ignition and re-ignition within specified standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spark igniters are used to ignite cooking gas, then ignition is achieved, but electronic components are damaged due to high electromotive force and audible clicking sounds are generated
Solution Approach 1:
The patent replaces the mechanical spark generation system (hammer striking piezoelectric crystal) with a hot surface igniter system that uses electrical resistance heating of a ceramic element to ignite gas. This substitution eliminates the high voltage electromagnetic pulses that damage electronics and the mechanical clicking sounds, while providing reliable ignition through sustained high temperature surface heating.
2Loss of time
If hot surface igniters are used for rapid ignition, then ignition time is reduced, but structural strength is insufficient
Solution Approach 1:
The patent employs a composite structure consisting of a ceramic heating element embedded in a metal housing or mounting structure. The ceramic material (such as alumina or silicon carbide) provides rapid heating capability and high-temperature stability, while the surrounding metal structure provides mechanical strength and structural support. This composite approach allows the igniter to achieve rapid ignition times while maintaining sufficient structural integrity for cooktop applications.
3Loss of substance
If ignition is attempted at lower gas flow rates, then gas waste is reduced, but reliable ignition becomes difficult to achieve
Solution Approach 1:
The patent implements a control system that activates the hot surface igniter before gas flow is established or simultaneously with low-level gas flow. The igniter pre-heats the ceramic element to ignition temperature, and the control system coordinates gas valve activation to ensure gas is present when the ceramic surface reaches sufficient temperature. This preliminary heating action enables reliable ignition even at lower gas flow rates, eliminating the need to maintain high gas flow solely for ignition purposes and reducing gas waste.
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
The solution provides a hot surface igniter that achieves rapid and reliable ignition and re-ignition at lower gas flow rates, reducing electronic component damage and noise, while meeting industry standards for ignition and re-ignition times, and extending the igniter's cycle life.
Implementation Method 1
Current flowing through the ceramic body causes the body to heat up and increase in temperature
Implementation Method 2
providing a source of ignition for the combustion gases
Data Source
AI summary
Hot surface igniter assemblies used in cooktops are shown and described. The hot surface igniters include a silicon nitride ceramic body with an embedded, resistive, heat-generating circuit. The igniters are less than 0.04 inches thick, and when energized, they reach surface temperatures in excess of 2000° F. in under 4 seconds to ignite combustible gas such as propane, butane, or natural gas. Examples of cook top burner systems are also provided which allow the igniter to remain on after ignition at a power level that is lower than during ignition but high enough to ignite the cooking gas should a flame out occur. Examples are also provided of burners that ignite on a low flow setting (e.g., simmer) as opposed the high flow settings that are common in cook top industry.