Feedback Controlled RTD Adjustment Aerosol Device
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Solution Overview
Problem
Electrically heated aerosol-generating devices experience variability in resistance-to-draw due to inconsistencies in the aerosol-forming substrate, such as porosity, humidity, and size, leading to inconsistent user experiences both between and during uses.
Innovation Solution
An electrically heated aerosol-generating device with a feedback control system that determines and automatically adjusts the resistance-to-draw of the airflow pathway using a pressure sensor and adjustable constriction, such as an iris diaphragm, to maintain a consistent resistance within a predetermined range, approximating that of a conventional lit-end cigarette.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment of resistance-to-draw is provided (e.g., rotatable element), then user can adjust resistance, but adjustment cannot be easily made during use and lacks accuracy/consistency
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated motor-driven iris diaphragm system. The motor receives control signals from the processor to automatically adjust the iris diaphragm position, eliminating the need for manual rotation while providing precise, consistent resistance-to-draw control during device operation.
Solution Approach 2:
The patent implements a feedback control system where the processor monitors device operation and sends control signals to the motor based on desired resistance-to-draw parameters. This closed-loop feedback enables automatic adjustment during use, maintaining accuracy and consistency without manual intervention.
2Device complexity
If fixed resistance-to-draw design is used, then device structure is simple, but resistance-to-draw varies significantly with substrate properties and user compression
Solution Approach 1:
The patent transforms the fixed resistance-to-draw design into a dynamic system where the iris diaphragm can automatically adjust its opening size via motor control. This dynamic adjustment compensates for variations in substrate properties and user compression, maintaining consistent resistance-to-draw despite changes in the aerosol-generating substrate.
Solution Approach 2:
The patent changes the resistance-to-draw parameter dynamically by adjusting the iris diaphragm opening size. The processor monitors and modifies this parameter in response to variations in substrate porosity, humidity, and compression, thereby maintaining reliability and consistency of the user experience.
3Measurement precision
If automated motor-driven iris diaphragm is added, then resistance-to-draw can be adjusted during use with accuracy, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the existing device architecture. The processor that already controls heating elements is extended to control the motor-driven iris diaphragm, and the airflow pathway serves both aerosol generation and resistance-to-draw control functions. This multi-functionality minimizes the increase in overall device complexity.
Solution Approach 2:
The patent merges the resistance-to-draw control mechanism with the existing airflow pathway and control electronics. The iris diaphragm is positioned within the existing airflow channel, and the motor control is integrated with the processor that already manages heating operations, combining multiple control functions into a unified system.
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 device provides a more consistent user experience by maintaining resistance-to-draw within a targeted range, allowing control over the quantity and droplet size of aerosol formed, thereby enhancing the mouth-feel and user satisfaction.
Implementation Method 1
means for determining the resistance-to-draw of the airflow pathway
Implementation Method 2
an electrical heater comprising at least one heating element for heating the aerosol-generating substrate in the cavity to generate an aerosol
Data Source
AI summary
An electrically heated aerosol-generating device and system are provided, the device including an outer housing having a cavity configured to receive an aerosol-generating substrate; an electrical heater including at least one heating element configured to heat the aerosol-generating substrate in the cavity to generate an aerosol; at least one air inlet, at least one air outlet; an airflow pathway extending from the at least one air inlet, through the cavity, to the at least one air outlet; means for determining the resistance-to-draw of the airflow pathway; and means for adjusting the resistance-to-draw of the airflow pathway in dependence on the determined resistance-to-draw. The system comprises an electrically heated aerosol-generating device and an aerosol-forming substrate comprising tobacco.