Hot Wire Anemometer Control for Puff Detection and Ambient Tracking
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Solution Overview
Problem
Existing non-nicotine electronic vaping devices lack effective control mechanisms for hot wire anemometers (HWAs) to manage power levels, puff detection, and ambient temperature changes, leading to inefficiencies in vapor production and airflow measurement.
Innovation Solution
Implementing a first PID controller to regulate power to the HWA based on temperature setpoints and a second PID controller to adjust temperature setpoints in response to ambient temperature changes, while generating puff detection signals and airflow measurements using pulse width modulation (PWM) drive signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hot wire anemometer is used for airflow measurement in a non-nicotine e-vaping device, then airflow detection capability is improved, but the device becomes sensitive to ambient temperature changes causing measurement inaccuracies
Solution Approach 1:
The patent implements a feedback control system where a second PID controller continuously monitors the HWA temperature and adjusts the temperature setpoint based on ambient temperature changes. This feedback mechanism compensates for ambient temperature effects on the hot wire anemometer, maintaining measurement accuracy across varying environmental conditions.
Solution Approach 2:
The system dynamically changes the operating parameters of the HWA by adjusting its temperature setpoint in response to ambient temperature variations. This parameter adaptation allows the anemometer to maintain optimal performance and measurement accuracy despite changes in environmental temperature.
2Measurement precision
If power to the hot wire anemometer is continuously adjusted for accurate airflow measurement, then measurement accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic action by using pulse width modulation (PWM) to control power delivery to the HWA. The first PID controller generates PWM drive signals that periodically adjust power levels based on the difference between actual and setpoint temperatures, enabling accurate measurement while reducing overall energy consumption compared to continuous full-power operation.
Solution Approach 2:
The system implements dynamic power adjustment through PID control that continuously adapts the power level to the actual operating conditions. The controller dynamically modifies the drive signal to the HWA based on real-time temperature feedback, maintaining measurement accuracy while optimizing energy usage according to actual measurement needs.
3Measurement precision
If multiple PID controllers are implemented for temperature and power control, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the control system into two distinct functional segments: a first PID controller dedicated to power control and a second PID controller dedicated to temperature setpoint management. This segmentation allows each controller to specialize in its specific function, improving overall control precision while organizing the complexity into manageable, modular components.
Solution Approach 2:
The control system achieves multi-functionality by having the first PID controller manage both power regulation and puff detection, while the second PID controller handles ambient temperature compensation. This universal approach allows the control system to perform multiple functions (power control, temperature control, puff detection, ambient compensation) through an integrated dual-controller architecture, managing complexity through functional consolidation.
4Measurement precision
If puff detection is implemented using drive signal gradient analysis, then puff detection accuracy is improved, but processing time increases
Solution Approach 1:
The system performs preliminary action by continuously monitoring and analyzing the gradient of the drive signal in real-time during normal operation. This ongoing gradient analysis is prepared in advance, allowing for immediate puff detection without requiring additional processing time when a puff event occurs, as the computational framework is already in place and actively monitoring.
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
Enhances the precision of puff detection and airflow measurement, improving the efficiency and consistency of non-nicotine vapor production by dynamically adjusting power and temperature settings.
Implementation Method 1
a first PID controller configured to control a level of power applied by the non-nicotine e-vaping device to the HWA based on a temperature of a heated element of the HWA and a temperature setpoint
Implementation Method 2
Hot wire anemometer (HWA) air flow measurement, puff detection and ambient temperature tracking
Data Source
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AI summary
A method of controlling a hot wire anemometer (HWA) of a non-nicotine e-vaping device includes controlling, by a first PID controller, a level of power applied by the non-nicotine e-vaping device to the HWA based on a temperature of a heated element of the HWA and a temperature setpoint; generating a puff detection signal indicating whether or not a puff is currently occurring with respect to the non-nicotine e-vaping device; and while the puff detection signal indicates that a puff is not currently occurring with respect to the non-nicotine e-vaping device, detecting, by a second PID controller, a change in an ambient temperature of the HWA, and controlling, by the second PID controller, the temperature setpoint such that the temperature setpoint changes in response to the detected change in the ambient temperature of the HWA.