Hot Surface Igniter Temperature Control via Thermal Resistance

The patent introduces thermal resistance as an intermediary parameter to bridge the gap between voltage control and temperature measurement. Instead of directly measuring the difficult-to-obtain actual voltage at the igniter, the system measures the easily obtainable thermal resistance (through voltage and current measurements) and uses this intermediary to infer temperature, thereby maintaining simple device architecture while achieving precise temperature control.

The patent replaces direct voltage measurement (electrical measurement) with thermal resistance measurement (thermal property measurement). This substitution allows the system to obtain accurate temperature information through electrical measurements of voltage and current across the igniter, converting an intractable electrical measurement problem into a solvable thermal characterization problem.

The patent implements a feedback control system that continuously monitors thermal resistance (which correlates with temperature) and adjusts the supply voltage accordingly. When the igniter approaches the target temperature, the system automatically reduces voltage to prevent overheating and damage, enabling both rapid heating and reliable operation through real-time closed-loop control.

The patent employs dynamic voltage adjustment rather than static voltage application. The supply voltage is continuously adapted based on the current temperature state of the igniter, allowing the system to apply high voltage for rapid initial heating, then smoothly transition to lower voltages as temperature increases, optimizing both heating speed and component safety throughout the heating process.