Inhaler Heater Control Using Dynamic Resistance Reference Updates

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Solution Overview

Problem

Existing inhalation device technologies face challenges in accurately detecting the temperature of a heater due to variations in the reference resistance value caused by parasitic resistance and contact resistance, leading to potential inaccuracies in detecting the dry state of the heater filament.

Innovation Solution

A controller for an inhalation device is developed, comprising a power supplier, a detection circuit, and a processor that updates the reference resistance value of the heater after each heating process, allowing for accurate temperature detection by continuously monitoring and adjusting the resistance value during heating processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the reference resistance value is measured before any heating is performed and used in all subsequent detection processes, then the device complexity is reduced, but the measurement precision deteriorates due to variations in parasitic resistance and contact resistance

Engineering Contradiction:
Improvedetection process complexityVSAvoidheater temperature detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The reference resistance value is dynamically updated after each heating operation based on the actual resistance measured at that time. This transforms the static reference value approach into a dynamic one that adapts to changes in parasitic resistance and contact resistance, thereby maintaining measurement precision without significantly increasing system complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by measuring the resistance value after each heating operation and using it to update the reference resistance value for the next operation. This feedback mechanism ensures that the reference value continuously adapts to changing conditions, resolving the contradiction between simplicity and precision

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the reference resistance value is updated after each heating operation, then the measurement precision is improved, but the device complexity increases due to additional detection and update processes

Engineering Contradiction:
Improveheater temperature detection precisionVSAvoiddetection and control process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically measuring its own resistance value after each heating operation and updating its reference value without external intervention. This self-service approach improves precision while minimizing the need for additional complex external calibration equipment or processes

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The resistance measurement and reference value update are performed in advance before the next heating operation begins. This preliminary action ensures that the reference value is ready and accurate for the upcoming operation, integrating the complexity into idle time rather than adding to operational complexity

Inventive Principle:
Principle #10Preliminary action

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

This solution ensures precise temperature control and detection of the heater, preventing overheating and ensuring consistent aerosol production by accounting for changes in resistance values, thereby improving the reliability of the inhalation device.

Implementation Method 1

a heater (127) that heats and atomizes an aerosol source

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a detection circuit (220) configured to detect a resistance value of the heater

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3874975B1Controller for inhalation device
Publication Date: 2023.10.25 JAPAN TOBACCO INC
  • EP3874975B1 patent drawingFigure 1
  • EP3874975B1 patent drawingFigure 2
  • EP3874975B1 patent drawingFigure 3

AI summary

A controller for an inhalation device comprises a power supplier 270 configured to supply power to a heater 127 used to heat and atomize an aerosol source, a detection circuit 220 configured to detect a resistance value of the heater, and a processor 240 configured to execute heating processing of heating the aerosol source by controlling the power supplier in accordance with reception of an atomization request of the aerosol source. The processor controls the heating processing based on the resistance value RHTR of the heater detected using the detection circuit and which depends on the temperature of the heater, a reference temperature of the heater, and a reference resistance value of the heater, and updates the reference resistance value by the resistance value of the heater detected using the detection circuit after an end of the heating processing and before the reception of the next atomization request.