Heater Control Using Resistance Feedback for Aerosol Compatibility

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Solution Overview

Problem

Existing electrically heated aerosol-generating systems struggle to operate effectively with heaters of different electrical resistances due to manufacturing tolerances and varying cartridge designs, and lack the ability to detect counterfeit or incompatible consumables.

Innovation Solution

An electrically operated aerosol-generating system that measures the initial and subsequent electrical resistance of the heater, determines differences beyond predefined thresholds, and controls power supply based on these differences to detect adverse conditions, allowing for compatibility and authenticity verification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the system uses a fixed threshold based on a particular heater resistance, then the temperature control is accurate for that specific heater, but the system cannot operate with heaters of different resistances

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidheater compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the threshold based on the measured heater resistance. Instead of using a fixed threshold, the control circuitry calculates a dynamic threshold that is proportional to the measured resistance value, allowing the system to adapt to different heater characteristics while maintaining accurate temperature control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the threshold parameter based on the heater resistance measurement. The threshold is transformed from a fixed value to a variable value that scales with the heater resistance, enabling the system to work with heaters of different resistances while maintaining the same temperature control accuracy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the system stores a threshold determined at manufacture, then the temperature control is optimised for that specific heater, but the system cannot detect counterfeit or incompatible consumables

Engineering Contradiction:
Improvetemperature control reliabilityVSAvoidcounterfeit detection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system performs a preliminary measurement of the heater resistance before normal operation and uses this measurement to establish the appropriate threshold. This preliminary action allows the system to both optimize temperature control for the specific heater and verify that the heater is genuine and compatible.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the heater resistance measurement to adjust the threshold and detect anomalies. By continuously monitoring the heater resistance and comparing it against expected values, the system can detect counterfeit or incompatible consumables while maintaining reliable temperature control.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the system uses a fixed threshold, then the device complexity is low, but the manufacturing precision requirements increase to ensure consistent heater resistance

Engineering Contradiction:
Improvecontrol system complexityVSAvoidheater resistance consistency
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system performs self-calibration by measuring the actual heater resistance and automatically adjusting the threshold accordingly. This self-service approach eliminates the need for high manufacturing precision while keeping the control system relatively simple, as the system adapts to each heater's specific characteristics.

Inventive Principle:
Principle #25Self-service

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

Enables operation with diverse heaters and consumables, preventing power supply to counterfeit or damaged components, ensuring consistent performance and user safety.

Implementation Method 1

an electric heater comprising at least one heating element for heating the liquid aerosol-forming substrate

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The system can use the electrical resistance of the heater element to calculate the temperature of the heating element

Methodology Applied
Scientific EffectElectrical resistance-temperature relationship: Electrical Resistance

Data Source

PatentEP3954236B1Heater control
Publication Date: 2025.09.17 PHILIP MORRIS PRODUCTS SA
  • EP3954236B1 patent drawingFigure 1a~1b
  • EP3954236B1 patent drawingFigure 1c~1d
  • EP3954236B1 patent drawingFigure 2~3

AI summary

An electrically operated aerosol-generating system comprising a heating element, a power supply, and electric circuitry (109) connected to the heating element and to the power supply and comprising a memory, the electric circuitry being configured to: measure an initial electrical resistance of the heating element; measure a subsequent electrical resistance of the heating element after the measurement of the initial electrical resistance and between user puffs on the system; determine the difference between the initial electrical resistance and the subsequent electrical resistance; compare the difference to a cooling threshold; and when the difference is above the cooling threshold, prevent or limit the supply of power to the heating element until the difference falls below the cooling threshold.