Dynamic Power Limiting for External Heater Pre-heating
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Solution Overview
Problem
Aerosol-generating devices with portable power supplies, such as rechargeable batteries, experience inconsistent performance due to varying voltage levels as the battery charge state changes, affecting the pre-heating time and aerosol production, especially with external heaters which have higher resistance and longer pre-heating phases.
Innovation Solution
The aerosol-generating device employs a controller that limits power supplied to the heater assembly during sequential time intervals to ensure a threshold energy is not exceeded, using a cumulative energy monitoring system to maintain consistent power delivery regardless of the battery's charge state, and incorporates a flexible heater assembly with heater tracks on a polyimide substrate for improved robustness and manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an external heater assembly is used to simplify manufacture and improve robustness, then device complexity is reduced, but pre-heating time increases due to higher resistance and lack of direct contact
Solution Approach 1:
The heating profile is made dynamic by adjusting power delivery in real-time based on the heater's thermal response. The system transitions from static predetermined heating routines to dynamic control where power is modulated to compensate for the external heater's higher thermal mass and resistance, maintaining consistent pre-heating performance across different battery charge states.
Solution Approach 2:
The system changes operational parameters (power level, heating duration, temperature targets) based on detected battery voltage levels. When battery voltage decreases, the controller adjusts heating parameters to ensure the external heater still reaches the required temperature, compensating for both the inherent slower heating rate and reduced power availability.
2Loss of time
If high power is supplied during pre-heating phase to reduce heating time, then pre-heating time is reduced, but power consumption increases and depletes battery faster
Solution Approach 1:
The heating process is divided into periodic phases with different power levels. The system applies high power during initial heating, then transitions to lower power maintenance phases, creating a periodic heating pattern that reduces overall energy consumption while maintaining effective pre-heating performance.
Solution Approach 2:
The system applies partial heating action by targeting specific temperature thresholds rather than continuously maximizing power. The heater is heated to the minimum required temperature for aerosol generation, avoiding excessive heating that would waste energy, while still achieving sufficient pre-heating in acceptable time.
3Device complexity
If predetermined heating routine with fixed time periods is used, then control is simplified, but user experience becomes inconsistent when battery charge state varies
Solution Approach 1:
The system implements feedback control by continuously monitoring battery voltage and heater temperature, then adjusting power delivery accordingly. This closed-loop control ensures consistent heating performance regardless of battery charge state, as the system compensates for varying power availability in real-time based on actual system conditions.
Solution Approach 2:
The heating profile transitions from static predetermined routines to dynamic adaptive control. The system continuously adjusts heating parameters based on real-time feedback from temperature sensors and battery voltage monitoring, enabling consistent performance across varying operating conditions without significantly increasing control complexity.
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 approach ensures consistent user experience by maintaining consistent pre-heating times and aerosol production across varying battery charge states, reduces power consumption, and extends the device's usage between charges, while minimizing the risk of overheating and improving device robustness.
Implementation Method 1
The heater assembly is heated when it is supplied with power from a power supply of the aerosol-generating device
Implementation Method 2
generate an aerosol from an aerosol-forming substrate
Data Source
AI summary
An aerosol-generating device for generating an aerosol from an aerosol-forming substrate during a usage session is provided, the device including: a timer; a heater assembly including a heater element to heat the substrate; a power supply to supply power to the heater assembly; and a controller, at least a portion of the usage session being divided into n sequential time intervals, the controller limiting power supplied to the heater assembly during any or each of the n sequential time intervals such that a threshold energy for that time interval is not exceeded, the controller monitoring a cumulative amount of energy supplied from the start of an nth sequential time interval, and limiting power supplied to the heater assembly until an end of the nth sequential time interval if the cumulative amount of energy supplied from the start of the nth time interval equals the threshold energy for that time interval.