EP4652871A1

EP4652871A1 - Aerosol generating apparatus

Info

Publication number: EP4652871A1
Application number: EP24177535.2A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: Imperial Tobacco Ltd United Kingdom
Current assignee: Imperial Tobacco Ltd United Kingdom
Priority date: 2024-05-23
Filing date: 2024-05-23
Publication date: 2025-11-26
Also published as: WO2025242551A1

Abstract

The invention provides and aerosol generating system comprising: a first tank for containing a first liquid aerosol precursor; a second tank for containing a second liquid aerosol precursor; an aerosol generation unit in fluid communication with the first and second tanks for generating a first aerosol from the first liquid aerosol precursor and generating a second aerosol from the second liquid aerosol precursor in response to an inhalation of a user; an inhalation sensor arranged to determine a strength of the inhalation; and a electrical circuitry adapted to: generate a control signal to cause the aerosol generation unit to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation

Description

FIELD

The present disclosure relates to an aerosol generating apparatus.

BACKGROUND

A typical aerosol generating apparatus may comprise a power supply, an aerosol generating unit that is driven by the power supply, an aerosol precursor, which in use is aerosolised by the aerosol generating unit to generate an aerosol, and a delivery system for delivery of the aerosol to a user.
In some cases, the aerosol generating unit may include an ultrasonic generator e.g. a piezoelectric transducer (PET) for generating the aerosol. In use, the surface of the PET will expand and contract as it vibrates.
A PET generates aerosol by causing cavitation to occur within a liquid aerosol precursor that is provided on a surface of the PET. Cavitation refers to the phenomenon where the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapour filled cavities within the liquid. When the cavities are subsequently subjected to a higher pressure, the cavities collapse resulting in a shock wave that propagates through the liquid. This shock wave induces capillary waves, or ripples, in a surface distal (referred to herein as the upper surface of the liquid) from the PET that may form ligaments to expel droplets from the upper surface. More succinctly, in a thin layer of liquid, the collapsing of the cavities can induce a disturbance in the liquid that causes liquid droplets to be expelled from liquid, thereby forming an aerosol over the surface of the liquid, typically within an aerosolisation chamber.
In the context of a PET for generating the aerosol, when the surface of the PET expands, the liquid on the surface will conform to the expanded surface. When the surface of the PET subsequently contracts, the static pressure in the liquid will fall as it is effectively dragged with the surface with the decrease in static pressure being proportional to the speed of the movement of the PET surface (i.e., the frequency of the vibration). If the frequency of vibration and the amplitude of the PET are sufficiently high, cavitation will occur as a result of the contraction.
When the surface of the PET subsequently expands, the static pressure in the liquid will rise as it is effectively compressed by the surface with the increase in static pressure being proportional to the speed of the movement of the PET surface (i.e., the frequency of the vibration). Any cavities in the liquid previously formed may then implode, generating shock waves in the liquid capable of expelling droplets to form an aerosol.
In an aerosol generating apparatus using a PET, a liquid aerosol precursor is typically applied to the PET surface using a wick in fluid communication with a tank. The aerosol generated by cavitation of the liquid aerosol precursor will be drawn from the aerosolisation chamber along an aerosol flow path by suction at a mouthpiece outlet.
Aerosol generating apparatuses that use a PET for generating the aerosol present numerous challenges, including accurately driving the vibrational element and inefficiencies in the requisite circuitry.
In spite of the effort already invested in the development of aerosol generating apparatuses/systems further improvements are desirable.

SUMMARY

The present disclosure provides aerosol generating system that comprises a first tank for containing a first liquid aerosol precursor, a second tank for containing a second liquid aerosol precursor and an aerosol generation unit in fluid communication with the first and second tanks for generating a first aerosol from the first liquid aerosol precursor and generating a second aerosol from the second liquid aerosol precursor in response to an inhalation of a user.
In some examples, the aerosol generating system further comprises an inhalation sensor arranged to determine a strength of the inhalation.
In some examples, the aerosol generating system further comprises a electrical circuitry adapted to generate a control signal to cause the aerosol generation unit to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation.
In other words, there is provided a means of controlling the concentration of the first aerosol within the combined aerosol, comprising both the first and the second aerosols, provided to the user.
Put another way, there is provided a means of adjusting the dilution of a first aerosol by a second aerosol within a total combined aerosol that is inhaled by the user.
By controlling the ratio of the amount of first aerosol generated to the amount of second aerosol generated based on the strength of the inhalation, the consistency in the amount of a given formulation, such as the first formulation, delivered to the user may be improved.
For example, when a strong inhalation is detected, the concentration of the first aerosol in the delivered mixture of aerosol may be decreased in order to prevent over-delivery of the first liquid aerosol precursor to the user. The concentration of the first aerosol in the delivered mixture of aerosol may be decreased by controlling the aerosol generation unit to generate less first aerosol and/or more second aerosol to make up the mixture of aerosols delivered to the user.
In a further example, when a weak inhalation is detected, the concentration of the first aerosol in the delivered mixture may be increased in order to prevent under-delivery of the first liquid aerosol precursor, for example, in order to achieve a satisfactory level of first aerosol delivery to the user. The concentration of the first aerosol in the delivered mixture of aerosol may be increased by controlling the aerosol generation unit to generate more first aerosol and/or less second aerosol to make up the mixture of aerosols delivered to the user.
The step of determining the strength of the inhalation may be performed during an initial period of an inhalation. The initial period of the inhalation may be less than the total inhalation period, i.e., may be less than the total duration of the inhalation.
In some examples, the first liquid aerosol precursor is a nicotine formulation. In some examples, the second liquid aerosol precursor is: a flavour formulation; or a plain formulation. In this way, the device may actively adjust the concentration of nicotine in the delivered mixture of aerosols based on the inhalation strength of the user.
For example, when a strong inhalation is detected, the concentration of the first aerosol in the delivered mixture of aerosol may be decreased in order to prevent over-delivery of the nicotine formulation to the user. In a further example, when a weak inhalation is detected, the concentration of the first aerosol in the delivered mixture may be increased in order to prevent under-delivery of the nicotine formulation, for example, in order to achieve a satisfactory level of nicotine delivery to the user.
In some examples, adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation comprises: comparing the strength of the inhalation to an upper inhalation strength threshold; and if the strength of the inhalation is greater than or equal to the upper inhalation strength threshold, decreasing the ratio of the first aerosol generated to the second aerosol generated.
In this way, the device may determine the relative strength of an inhalation in order to adjust the ratio of the first aerosol generated to the second aerosol generated. In particular, the device compares the measured inhalation strength to a threshold value, i.e., the upper inhalation strength threshold, and, if the measured inhalation strength meets or exceeds the upper inhalation strength threshold, the device may determine that the inhalation is relatively strong. When an inhalation is determined to be a strong inhalation, the concentration of the first aerosol in the delivered mixture of aerosol may be decreased in order to prevent over-delivery of the first aerosol, which may comprise a nicotine formulation, to the user.
The measured inhalation strength may be a relative pressure measurement, i.e., a change in sensed pressure from a baseline, such as atmospheric pressure, in response to a user inhalation. Alternatively, the measured inhalation strength may be an absolute pressure measurement.
The upper inhalation strength threshold may be a predetermined threshold set at a predetermined pressure value. Alternatively, the upper inhalation strength threshold may be set to a predetermined deviation from a baseline pressure, for example a percentage increase in pressure. The upper inhalation strength threshold may be adjusted over time based on an average inhalation strength of the user.
In some examples, adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation comprises: comparing the strength of the inhalation to a lower inhalation strength threshold; and if the strength of the inhalation is less than or equal to the lower inhalation strength threshold, increasing the ratio of the first aerosol generate to the second aerosol generated.
In this way, the device may determine the relative strength of an inhalation in order to adjust the ratio of the first aerosol generated to the second aerosol generated. In particular, the device compares the measured inhalation strength to a threshold value, i.e., the lower inhalation strength threshold, and, if the measured inhalation strength meets or falls below the lower inhalation strength threshold, the device may determine that the inhalation is relatively weak. When an inhalation is determined to be a weak inhalation, the concentration of the first aerosol in the delivered mixture of aerosol may be increased in order to prevent under-delivery of the first aerosol, which may comprise a nicotine formulation, to the user.
The measured inhalation strength may be a relative pressure measurement, i.e., a change in sensed pressure from a baseline, such as atmospheric pressure, in response to a user inhalation. Alternatively, the measured inhalation strength may be an absolute pressure measurement.
The lower inhalation strength threshold may be a predetermined threshold set at a predetermined pressure value. Alternatively, the lower inhalation strength threshold may be set to a predetermined deviation from a baseline pressure, for example a percentage increase in pressure. The lower inhalation strength threshold may be adjusted over time based on an average inhalation strength of the user.
The upper inhalation strength threshold and the lower inhalation strength threshold may form a range within which an average inhalation strength lies. Any inhalation of the user will cause an increase in the measured pressured compared to a baseline pressure measured by the inhalation sensor when no inhalation is occurring. In response to an average strength inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies between the upper inhalation strength threshold and the lower inhalation strength threshold. In response to a strong inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies at or above the upper inhalation strength threshold. In response to a weak inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies at or below the lower inhalation strength threshold.
In some examples, the aerosol generating unit comprises a first piezoelectric transducer for generating the first aerosol from the first liquid aerosol precursor and a second piezoelectric transducer for generating the second aerosol from the second liquid aerosol precursor.
By using piezoelectric transducers for generating the first and second aerosols, the speed at, or reactivity with, which the first and second aerosol generator can be activated, deactivated and controlled may be improved, for example when compared to heaters which have lag times associated with heating up and cooling down.
In some examples, the device further comprises a drive circuit adapted to: drive the first piezoelectric transducer according to a first set of driving parameters; and drive the second piezoelectric transducer according to a second set of driving parameters.
The driving parameters of a piezoelectric transducer have a direct correspondence to the type, and amount, of aerosol generated by the piezoelectric transducer. By driving the first piezoelectric transducer according to a first set of driving parameters and the second piezoelectric transducer according to a second set of driving parameters, the amount of first aerosol generated in response to an inhalation of the user may be controlled independently of the amount of second aerosol generated. Thus, the ratio of the first aerosol generated to the second aerosol generated may be more accurately controlled.
In some examples, generating the control signal to cause the aerosol generation unit to adjust a ratio between the first aerosol generated in response to the inhalation and the second aerosol generated in response to the inhalation comprises: generating a control signal to cause the driving circuit to adjust one or more of the first set of driving parameters and/or one or more of the second set of driving parameters.
Through the independent control of the first piezoelectric transducer using the first set of driving parameters and the second piezoelectric transducer using the second set of driving parameters, the ratio of the first aerosol generated to the second aerosol generated my be controlled through the adjustment of the first set of driving parameters and/or the second set of driving parameters.
In some examples, the first set of driving parameters comprises one or more of: a first driving frequency; a first driving duty cycle; and a first driving power; and wherein the second set of driving parameters comprises one or more of: a second driving frequency; a second driving duty cycle; and a second driving power.
Adjusting the ratio of the first aerosol generated to the second aerosol generated may be performed by adjusting any one of the driving parameters in the first and second sets of driving parameters, thereby providing multiple different means of adjusting the behaviour of the first and/or second piezoelectric transducer in order to adjust the ratio of the first aerosol generated to the second aerosol generated.
In some examples, decreasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of: decreasing the first driving duty cycle; decreasing the first driving power; increasing the second driving duty cycle; and increasing the second driving power.
Put another way, decreasing the ratio of the first aerosol generated to the second aerosol generated may be performed by: adjusting one or more of the first set of driving parameters for driving the first piezoelectric transducer to decrease the amount of first aerosol generated; adjusting one or more of the second set of driving parameters for driving the second piezoelectric transducer to increase the amount of second aerosol generated; or a combination of both.
In some examples, increasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of: increasing the first driving duty cycle; increasing the first driving power; decreasing the second driving duty cycle; and decreasing the second driving power.
Put another way, increasing the ratio of the first aerosol generated to the second aerosol generated may be performed by: adjusting one or more of the first set of driving parameters for driving the first piezoelectric transducer to increase the amount of first aerosol generated; adjusting one or more of the second set of driving parameters for driving the second piezoelectric transducer to decrease the amount of second aerosol generated; or a combination of both.
For example, when a strong inhalation is detected, the first driving power may be decreased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent over-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a strong inhalation is detected, the second driving power may be increased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In a further example, when a weak inhalation is detected, the first driving power may be increased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent under-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a weak inhalation is detected, the second driving power may be decreased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In another example, when a strong inhalation is detected, the first driving duty cycle may be decreased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent over-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a strong inhalation is detected, the second driving duty cycle may be increased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In a further example, when a weak inhalation is detected, the first driving duty cycle may be increased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent under-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a weak inhalation is detected, the second driving duty cycle may be decreased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In some examples, generating the control signal to cause the aerosol generation unit to adjust a ratio between the first aerosol generated in response to the inhalation and the second aerosol generated in response to the inhalation comprises: delaying the generation of one of the first aerosol and the second aerosol with respect to the generation of the other of the first aerosol and the second aerosol, thereby reducing an aerosol generation time for one of the first aerosol and the second aerosol.
Rather than, or in addition to, adjusting the driving parameters of a piezoelectric transducer, the ratio of the first aerosol generated to the second aerosol generated may be adjusted by delaying the generation of one aerosol with respect to another. For example, in order to decrease the ratio of first aerosol to second aerosol present in an inhalation, the generation of the first aerosol may be delayed with respect to the generation of the second aerosol, such that the first aerosol is generated for only part of the inhalation. Correspondingly, in order to increase the ratio of first aerosol to second aerosol present in an inhalation, the generation of the second aerosol may be delayed with respect to the generation of the first aerosol, such that the second aerosol is generated for only part of the inhalation.
In some examples, decreasing the ratio of the first aerosol generated to the second aerosol generated comprises delaying the generation of the first aerosol with respect to the generation of the second aerosol, thereby reducing an aerosol generation time for the first aerosol.
In some examples, increasing the ratio of the first aerosol generated to the second aerosol generated comprises delaying the generation of the second aerosol with respect to the generation of the first aerosol, thereby reducing an aerosol generation time for the second aerosol.
For example, when a strong inhalation is detected, the generation of the first aerosol may be delayed with respect to the generation of the second aerosol in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent over-delivery of the nicotine formulation to the user. In a further example, when a weak inhalation is detected, the generation of the second aerosol may be delayed with respect to the generation of the first aerosol in order to increase the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent under-delivery of the nicotine formulation to the user.
The present disclosure may provide a method controlling an aerosol generating system as described above, which may implement any one or more features disclosed herein. The method may comprise obtaining the strength of the inhalation from the inhalation sensor and generating a control signal to cause the aerosol generation unit to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation.
The present disclosure may provide electrical circuitry and/or a computer program configured to cause an aerosol generating apparatus/system to perform any method or method step disclosed herein. A computer readable medium comprising the computer program is also disclosed.
In embodiments, the electrical circuitry is implemented as one or more processors, which are configured to implement the disclosed steps, e.g. as the controller. The processors may execute program code stored on electronic memory and/or may execute logic, e.g. as a logic array, gate array, structured gate array.
The preceding summary is provided for purposes of summarizing some examples to provide a basic understanding of aspects of the subject matter described herein. Accordingly, the above-described features should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Moreover, the above and/or proceeding examples may be combined in any suitable combination to provide further examples, except where such a combination is clearly impermissible or expressly avoided. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following text and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

Aspects, features and advantages of the present disclosure will become apparent from the following description of examples in reference to the appended drawings in which like numerals denote like elements.

Fig. 1 is a block system diagram showing an example aerosol generating apparatus.
Fig. 2 is a block system diagram showing an example implementation of the apparatus of Fig. 1, where the aerosol generating apparatus is configured to generate aerosol from a liquid precursor.
Figs. 3A and 3B are schematic diagrams showing an example implementation of the apparatus of Fig. 2.
Fig. 4 is a block system diagram showing an example system for managing an aerosol generating apparatus.
Fig. 5 shows an example of a circuit for modelling the behaviour of an exemplary piezoelectric transducer.
Fig. 6 shows a portion of an exemplary driving circuit using an H-bridge.
Fig. 7 shows an example of an improved driving circuit for driving a piezoelectric transducer.
Fig. 8 shows a schematic representation of an aerosol generating system according to an aspect of the invention.
Fig. 9 shows a method for controlling the aerosol generating system shown in Fig. 8.
Fig. 10 shows a further method for controlling the aerosol generating system shown in Fig. 8.
Fig. 11 shows a schematic representation of the methods shown in Figs. 9 and 10.

DETAILED DESCRIPTION OF EMBODIMENTS

Before describing several examples implementing the present disclosure, it is to be understood that the present disclosure is not limited by specific construction details or process steps set forth in the following description and accompanying drawings. Rather, it will be apparent to those skilled in the art having the benefit of the present disclosure that the systems, apparatuses and/or methods described herein could be embodied differently and/or be practiced or carried out in various alternative ways.
Unless otherwise defined herein, scientific and technical terms used in connection with the presently disclosed inventive concept(s) shall have the meanings that are commonly understood by those of ordinary skill in the art, and known techniques and procedures may be performed according to conventional methods well known in the art and as described in various general and more specific references that may be cited and discussed in the present specification.
Any patents, published patent applications, and non-patent publications mentioned in the specification are hereby incorporated by reference in their entirety.
All examples implementing the present disclosure can be made and executed without undue experimentation in light of the present disclosure. While particular examples have been described, it will be apparent to those of skill in the art that variations may be applied to the systems, apparatus, and/or methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit, and scope of the inventive concept(s). All such similar substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the inventive concept(s) as defined by the appended claims.
The use of the term "a" or "an" in the claims and/or the specification may mean "one," as well as "one or more," "at least one," and "one or more than one." As such, the terms "a," "an," and "the," as well as all singular terms, include plural referents unless the context clearly indicates otherwise. Likewise, plural terms shall include the singular unless otherwise required by context.
The use of the term "or" in the present disclosure (including the claims) is used to mean an inclusive "and/or" unless explicitly indicated to refer to alternatives only or unless the alternatives are mutually exclusive. For example, a condition "A or B" is satisfied by any of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
As used in this specification and claim(s), the words "comprising, "having," "including," or "containing" (and any forms thereof, such as "comprise" and "comprises," "have" and "has," "includes" and "include," or "contains" and "contain," respectively) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
Unless otherwise explicitly stated as incompatible, or the physics or otherwise of the embodiments, examples, or claims prevent such a combination, the features of examples disclosed herein, and of the claims, may be integrated together in any suitable arrangement, especially ones where there is a beneficial effect in doing so. This is not limited to only any specified benefit, and instead may arise from an "ex post facto" benefit. This is to say that the combination of features is not limited by the described forms, particularly the form (e.g. numbering) of example(s), embodiment(s), or dependency of claim(s). Moreover, this also applies to the phrase "in one embodiment," "according to an embodiment," and the like, which are merely a stylistic form of wording and are not to be construed as limiting the following features to a separate embodiment to all other instances of the same or similar wording. This is to say, a reference to 'an,' 'one,' or 'some' embodiment(s) may be a reference to any one or more, and/or all embodiments, or combination(s) thereof, disclosed. Also, similarly, the reference to "the" embodiment may not be limited to the immediately preceding embodiment. Further, all references to one or more embodiments or examples are to be construed as non-limiting to the claims.
The present disclosure may be better understood in view of the following explanations, wherein the terms used that are separated by "or" may be used interchangeably:
As used herein, an "aerosol generating apparatus" (or "electronic(e)-cigarette") may be an apparatus configured to deliver an aerosol to a user for inhalation by the user. The apparatus may additionally/alternatively be referred to as a "smoking substitute apparatus", if it is intended to be used instead of a conventional combustible smoking article. As used herein a combustible "smoking article" may refer to a cigarette, cigar, pipe or other article, that produces smoke (an aerosol comprising solid particulates and gas) via heating above the thermal decomposition temperature (typically by combustion and/or pyrolysis). An aerosol generated by the apparatus may comprise an aerosol with particle sizes of 0.2 - 7 microns, such as between 2 - 3 microns, or less than 10 microns, or less than 7 microns, or less than 3 microns, or less than 2 microns. This particle size may be achieved by control of one or more of: driving parameters of the ultrasonic generator; flow properties including turbulence and velocity. The generation of aerosol by the aerosol generating apparatus may be controlled by an input device. The input device may be configured to be user-activated, and may for example include or take the form of an actuator (e.g. actuation button) and/or an airflow sensor.
Each occurrence of the aerosol generating apparatus being caused to generate aerosol for a period of time (which may be variable) may be referred to as an "activation" of the aerosol generating apparatus. The aerosol generating apparatus may be arranged to allow an amount of aerosol delivered to a user to be varied per activation (as opposed to delivering a fixed dose of aerosol), e.g. by activating an aerosol generating unit of the apparatus for a variable amount of time, e.g. based on the strength/duration of a draw of a user through a flow path of the apparatus (to replicate an effect of smoking a conventional combustible smoking article).
The aerosol generating apparatus may be portable. As used herein, the term "portable" may refer to the apparatus being for use when held by a user.
As used herein, an "aerosol generating system" may be a system that includes an aerosol generating apparatus and optionally other circuitry/components associated with the function of the apparatus, e.g. one or more external devices and/or one or more external components (here "external" is intended to mean external to the aerosol generating apparatus).
As used herein, an "external device" and "external component" may include one or more of a: a charging device, a mobile device (which may be connected to the aerosol generating apparatus, e.g. via a wireless or wired connection); a networked-based computer (e.g. a remote server); a cloud-based computer; any other server system.
An example aerosol generating system may be a system for managing an aerosol generating apparatus. Such a system may include, for example, a mobile device, a network server, as well as the aerosol generating apparatus.
As used herein, an "aerosol" may include a suspension of liquid droplets of precursor. An aerosol may include one or more components of the precursor.
As used herein, a "precursor" may include one or more of a: liquid; and a gel. The precursor may be processed by an aerosol generating unit of an aerosol generating apparatus to generate an aerosol. The precursor may include one or more of: an active component; a carrier; a flavouring. The active component may include one or more of nicotine; caffeine; a cannabidiol oil; a non-pharmaceutical formulation, e.g. a formulation which is not for treatment of a disease or physiological malfunction of the human body. The active component may be carried by the carrier, which may be a liquid, including propylene glycol and/or glycerine. The term "flavouring" may refer to a component that provides a taste and/or a smell to the user. The flavouring may include one or more of: Ethylvanillin (vanilla); menthol, Isoamyl acetate (banana oil); or other. The precursor may include a carrier; a flavouring.
As used herein, a "storage portion" may be a portion of the apparatus adapted to store the precursor. It may be implemented as fluid-holding reservoir depending on the implementation of the precursor as defined above.
As used herein, a "flow path" may refer to a path or enclosed passageway through an aerosol generating apparatus, e.g. for delivery of an aerosol to a user. The flow path may be arranged to receive aerosol from an aerosol generating unit. When referring to the flow path, upstream and downstream may be defined in respect of a direction of flow in the flow path, e.g. with an outlet being downstream of an inlet.
As used herein, a "delivery system" may be a system operative to deliver an aerosol to a user. The delivery system may include a mouthpiece and a flow path. The delivery system may be at least partly within the aerosol generating component.
As used herein, a "flow" may refer to a flow in a flow path. A flow may include aerosol generated from the precursor. The flow may include air, which may be induced into the flow path via a puff by a user.
As used herein, a "puff" (or "inhale" or "draw") by a user may refer to expansion of lungs and/or oral cavity of a user to create a pressure reduction that induces flow through the flow path.
As used herein, an "aerosol generating unit" may refer to a device configured to generate an aerosol from a precursor. The aerosol generating unit may include a unit to generate an aerosol directly from the precursor (e.g. an atomiser including an ultrasonic system). A plurality of aerosol generating units to generate a plurality of aerosols (for example, from a plurality of different aerosol precursors) may be present in an aerosol generating apparatus.
As used herein, an "ultrasonic generator" may refer to a piezoelectric transducer capable of vibrating at ultrasonic frequencies, i.e., at frequencies greater than 20kHz. In some examples, the piezoelectric transducer may be capable of vibrating at even higher frequencies, e.g., at frequencies of 100 kHz or above, 500 kHz or above, 1 MHz or more, 2 MHz or more, 5 MHz or more, or 10 MHz or more. The piezoelectric transducer may be adapted to vibrate in response to a driving signal, and in particular adapted to vibrate at the frequency of the driving signal. In some examples, the driving signal may be generated by direct digital synthesis (DDS).
As used herein, a "piezoelectric transducer" may refer to an ultrasonic transducer comprising a piezoelectric crystal, which generates a mechanical strain internally in response to an electric field. A rapidly changing electric field, such as an ultrasonic frequency driving signal, results in rapidly changing mechanical strain within the piezoelectric crystal causing it to vibrate. The piezoelectric transducer will have an aerosolisation surface from which the aerosol is generated. The aerosolisation surface typically faces into an aerosolisation chamber.
As used herein, an "aerosol generating component" may refer to a component that includes an aerosol precursor. The component may include an aerosol generating unit e.g. it may be arranged as a cartomizer. The component may include a mouthpiece. The component may include an information carrying medium. The component may include a storage portion, e.g. a reservoir or tank, for storage of the aerosol precursor.
With liquid or gel implementations of the aerosol precursor, e.g. an e-liquid, the component may be referred to as a "capsule" or a "pod" or an "e-liquid consumable". In some embodiments, the aerosol precursor component may be affixed to the device body to form the aerosol generating apparatus. In these embodiments, the reservoir/tank may be refillable.
The aerosol generating component e.g. the capsule, pod, or consumable may be for releasable coupling to a device body to form the aerosol generating apparatus.
The device body may comprise a power supply for powering the aerosol generating unit.
As used herein, an "information carrying medium" may include one or more arrangements for storage of information on any suitable medium. Examples include: a computer readable medium; a Radio Frequency Identification (RFID) transponder; codes encoding information, such as optical (e.g. a bar code or QR code) or mechanically read codes (e.g. a configuration of the absence or presents of cutouts to encode a bit, through which pins or a reader may be inserted).
As used herein, "electrical circuitry" may refer to one or more electrical components, examples of which may include: an Application Specific Integrated Circuit (ASIC) or other programable logic; electronic/electrical componentry (which may include combinations of transistors, resistors, capacitors, inductors etc); one or more processors (e.g. the circuitry structure of the processor); a non-transitory memory (e.g. implemented by one or more memory devices), that may store one or more software or firmware programs; a combinational logic circuit; interconnection of the aforesaid.
The electrical circuitry may be located entirely at the apparatus (e.g., in the device/main body comprising the power supply), or distributed between the apparatus and/or on one or more external devices in communication with the apparatus, e.g. as part of a system. The electrical circuitry may comprise a controller. The controller may be configured to carry out any of the methods described herein.
As used herein, a "processing resource" (or "processor" or "controller") may refer to one or more units for processing data, examples of which may include an ASIC, microcontroller, FPGA, microprocessor, digital signal processor (DSP) capability, state machine or other suitable component. A processing resource may be configured to execute a computer program, e.g. which may take the form of machine readable instructions, which may be stored on a non-transitory memory and/or programmable logic. The processing resource may have various arrangements corresponding to those discussed for the circuitry, e.g. on-board and/or off board the apparatus as part of the system. As used herein, any machine executable instructions, or computer readable media, may be configured to cause a disclosed method to be carried out, e.g. by an aerosol generating apparatus or system as disclosed herein, and may therefore be used synonymously with the term method.
As used herein, an "external device" (or "peripheral device") may include one or more electronic components external to an aerosol generating apparatus. Those components may be arranged at the same location as the aerosol generating apparatus or remote from the apparatus. An external device may comprise electronic computer devices including: a smartphone; a PDA; a video game controller; a tablet; a laptop; or other like device.
As used herein, a "computer readable medium/media" (or "memory" or "data storage") may include any medium capable of storing a computer program, and may take the form of any conventional non-transitory memory, for example one or more of: random access memory (RAM); a CD; a hard drive; a solid state drive; a memory card; a DVD. The memory may have various arrangements corresponding to those discussed for the circuitry /processor. The present disclosure includes a computer readable medium configured to cause an apparatus or system disclosed herein to perform a method as disclosed herein.
As used herein, a "communication resource" (or "communication interface") may refer to hardware and/or firmware for electronic information/data transfer. The communication resource may be configured for wired communication ("wired communication resources") or wireless communication ("wireless communication resource"). Wireless communication resources may include hardware to transmit and receive signals by radio and may include various protocol implementations e.g. the 802.11 standard described in the Institute of Electronics Engineers (IEEE) and Bluetooth^™ from the Bluetooth Special Interest Group of Kirkland Wash. Wired communication resources may include; Universal Serial Bus (USB); High-Definition Multimedia Interface (HDMI) or other protocol implementations. The apparatus may include communication resources for wired or wireless communication with an external device.
As used herein, a "network" (or "computer network") may refer to a system for electronic information/data transfer between a plurality of apparatuses/devices. The network may, for example, include one or more networks of any type, which may include: a Public Land Mobile Network (PLMN); a telephone network (e.g. a Public Switched Telephone Network (PSTN) and/or a wireless network); a local area network (LAN); a metropolitan area network (MAN); a wide area network (WAN); an Internet Protocol Multimedia Subsystem (IMS) network; a private network; the Internet; an intranet.
It will be appreciated that any of the disclosed methods (or corresponding apparatuses, programs, data carriers, etc.) may be carried out by either a host or client, depending on the specific implementation (i.e. the disclosed methods/apparatuses are a form of communication(s), and as such, may be carried out from either 'point of view', i.e. in corresponding to each other fashion). Furthermore, it will be understood that the terms "receiving" and "transmitting" encompass "inputting" and "outputting" and are not limited to an RF context of transmitting and receiving electromagnetic (e.g. radio) waves. Therefore, for example, a chip or other device or component for realizing embodiments could generate data for output to another chip, device or component, or have as an input data from another chip, device, or component, and such an output or input could be referred to as "transmit" and "receive" including gerund forms, that is, "transmitting" and "receiving," as well as such "transmitting" and "receiving" within an RF context.
Referring to Fig. 1, an example aerosol generating apparatus 1 includes a power supply 2, for supply of electrical energy. The apparatus 1 includes an aerosol generating unit 4 that is driven by the power supply 2. The power supply 2 may include an electric power supply in the form of a battery and/or an electrical connection to an external power source. The apparatus 1 includes a precursor 6, which in use is aerosolised by the aerosol generating unit 4 to generate an aerosol. The aerosol generating unit 4 includes a piezoelectric transducer (discussed below) configured to induce, by vibration of the piezoelectric transducer i.e. vibration of an aerosolisation surface of the piezoelectric transducer, cavitation in the precursor 6. Collapse of the cavities in the precursor 6 induces a shock that propagates through the liquid precursor 6. This shock disturbs a surface of the liquid precursor 6 that interfaces with air within an aerosolisation chamber of the aerosol generating apparatus 1 (which in turn is in fluid communication with an airflow path within the aerosol generating apparatus). These disturbances take the form of ripples, also known as capillary waves, that form ligaments at the peaks of the ripples/waves, pinch off and expel droplets from the liquid precursor 6 into the airflow path, thereby aerosolising the precursor 6 to generate the aerosol. The apparatus 2 includes a delivery system 8 for delivery of the aerosol to a user.
Electrical circuitry (not shown in figure 1) may be implemented to control the interoperability of the power supply 2 and aerosol generating unit 4.
Fig. 2 shows an implementation of the apparatus 1 of Fig. 1, where the aerosol generating apparatus 1 is configured to generate aerosol from a liquid precursor.
In this example, the apparatus 1 includes a device body 10 and a consumable 30.
In this example, the body 10 includes the power supply 2. The body may additionally include any one or more of electrical circuitry 12, a memory 14, a wireless interface 16, one or more other components 18.
The electrical circuitry 12 may include a processing resource for controlling one or more operations of the body 10 and consumable 30, e.g. based on instructions stored in the memory 14.
The wireless interface 16 may be configured to communicate wirelessly with an external (e.g. mobile) device, e.g. via Bluetooth, Bluetooth LE (Low Energy), or WiFi.
The other component(s) 18 may include one or more user interface devices configured to convey information to a user and/or a charging port, for example (see e.g. Fig. 3).
The consumable 30 includes a storage portion implemented here as a tank 32 which stores the liquid precursor 6 (e.g. e-liquid). The consumable 30 also includes one or more air inlets 36, and a mouthpiece 38. The consumable 30 may include one or more other components 40.
The body 10 and consumable 30 may each include a respective electrical interface (not shown) to provide an electrical connection between one or more components of the body 10 with one or more components of the consumable 30. In this way, electrical power can be supplied to components of the consumable 30, without the consumable 30 needing to have its own power supply.
The piezoelectric transducer 34 of the aerosol generating unit 4 is arranged to be in electrical contact with one or more components of the body 10. For example, the power supply 2 may be configured to provide power to the piezoelectric transducer 34. Additionally or alternatively, the piezoelectric transducer 34 may be in electrical contact/communication with one or more of the electrical circuitry 12, memory 14, wireless interface 16 or one or more of the one or more other components 18 e.g., to receive instructions to adjust an operating parameter of the piezoelectric transducer 34 and/or to transmit data indicative of the operational parameters of the piezoelectric transducer 34.
Moreover, the piezoelectric transducer 34 is arranged to be in fluid communication with the tank 32 e.g. via a wick such that the liquid precursor can be provided to the aerosolisation surface of the piezoelectric transducer 34.
In use, a user may activate the aerosol generating apparatus 1 when inhaling through the mouthpiece 38, i.e. when performing a puff. The puff, performed by the user, may initiate a flow through a flow path in the consumable 30 which extends from the air inlet(s) 36 to the mouthpiece 38 via a region (i.e. an aerosolisation chamber) in proximity to the piezoelectric transducer 34.
Activation of the aerosol generating apparatus 1 may be initiated, for example, by an airflow sensor in the body 10 which detects airflow in the aerosol generating apparatus 1 (e.g. caused by a user inhaling through the mouthpiece), or by actuation of an actuator included in the body 10. Upon activation, the electrical circuitry 12 (e.g. under control of the processing resource) may supply electrical energy from the power supply 2 to the piezoelectric transducer 34 of the aerosol generating unit 4, which may cause the piezoelectric transducer 34 to induce cavitation in the liquid precursor 6 drawn from the tank so as to produce an aerosol which is carried by the flow out of the mouthpiece 38.
In some examples, the consumable may include a wick, wherein a first portion of the wick extends into the tank 32 in order to draw liquid precursor 6 out from the tank 32 and wherein a second portion of the wick is arranged to convey the drawn liquid precursor 6 to the aerosolisation surface piezoelectric transducer 34of the aerosol generating unit 4.
In this example, the delivery system 8 is provided by the above-described flow path and mouthpiece 38.
In variant embodiments (not shown), any one or more of the precursor 6, air inlet(s) 36 and mouthpiece 38, may be included in the body 10. For example, the mouthpiece 36 may be included in the body 10 with the precursor 6 arranged as a separable cartomizer.
Figs. 3A and 3B show an example implementation of the aerosol generating apparatus 1 of Fig. 2. In this example, the consumable 30 is implemented as a capsule/pod, which is shown in Fig. 3A as being physically coupled to the body 10, and is shown in Fig. 3B as being decoupled from the body 10.
In this example, the body 10 and the consumable 30 are configured to be physically coupled together by pushing the consumable 30 into an aperture in a top end 11 the body 10, with the consumable 30 being retained in the aperture via an interference fit.
In other examples (not shown), the body 10 and the consumable 30 could be physically coupled together in other ways, e.g. by screwing one onto the other, through a bayonet fitting, or through a snap engagement mechanism, for example.
The body 10 also includes a charging port (not shown) at a bottom end 13 of the body 10.
The body 10 also includes a user interface device configured to convey information to a user. Here, the user interface device is implemented as a light 15, which may e.g. be configured to illuminate when the apparatus 1 is activated. Other user interface devices are possible, e.g. to convey information haptically or audibly to a user.
In this example, the consumable 30 has an opaque cap 31, a translucent tank 32 and a translucent window 33. When the consumable 30 is physically coupled to the body 10 as shown in Fig. 3A, only the cap 31 and window 33 can be seen, with the tank 32 being obscured from view by the body 10. The body 10 includes a slot 15 to accommodate the window 33. The window 33 is configured to allow the amount of liquid precursor 6 in the tank 32 to be visually assessed, even when the consumable 30 is physically coupled to the body 10.
Fig. 4 shows an example system 80 for managing an aerosol generating apparatus 1, such as those described above with reference to any of Figs. 1-3B.
The system 80 as shown in Fig. 1 includes a mobile device 82, an application server 84, an optional charging station 86, as well as the aerosol generating apparatus 1.
In this example, aerosol generating apparatus 1 is configured to communicate wirelessly, e.g. via Bluetooth^™, with an application (or "app") installed on the mobile device 2, via a wireless interface included in the aerosol generating apparatus 1 and via a wireless interface included in the mobile device 82. The mobile device 82 may be a mobile phone, for example. The application on the mobile phone is configured to communicate with the application server 84, via a network 88. The application server 84 may utilise cloud storage, for example.
The network 88 may include a cellular network and/or the internet.
In other examples, the aerosol generating apparatus 1 may be configured to communicate with the application server 84 via a connection that does not involve the mobile device 82, e.g. via a narrowband internet of things ("NB-loT") or satellite connection. In some examples, the mobile device 82 may be omitted from the system 80.
A skilled person would readily appreciate that the mobile device 82 may be configured to communicate via the network 88 according to various communication channels, preferably a wireless communication channel such as via a cellular network (e.g. according to a standard protocol, such as 3G or 4G) or via a WiFi network.
The app installed on the mobile device 82 and the application server 84 may be configured to assist a user with managing their aerosol generating apparatus 1, based on information communicated between the aerosol generating apparatus 1 and the app, information communicated directly between the aerosol generating apparatus 1 and the application server 84, and/or information communicated between the app and the application server 84.
The charging station 86 (if present) may be configured to charge (and optionally communicate with) the aerosol generating apparatus 1, via a charging port on the aerosol generating apparatus 1. The charging port on the smoking substitute device 10 may be a USB port, for example, which may allow the aerosol generating apparatus 1 to be charged by any USB-compatible device capable of delivering power to the aerosol generating apparatus 1 via a suitable USB cable (in this case the USB-compatible device would be acting as the charging station 86). Alternatively, the charging station could be a docking station specifically configured to dock with the aerosol generating apparatus 1 and charge the aerosol generating apparatus 1via the charging port on the aerosol generating apparatus 1.
Fig. 5 shows an example of a circuit for modelling the behaviour of a piezoelectric transducer 100 at the resonant frequency of the piezoelectric transducer 100. Example circuits for providing a driving signal to the piezoelectric transducer 100 are described below with reference to Figures 6 and 7.
The circuit includes a set of components connected in series with each other between a pair of terminals 110a, 110b, including: an inductor 120; a resistor 130; and an in-series capacitor 140. The set of series components are connected in parallel with an in-parallel capacitor 150. Each of the components of the circuit model different aspects of the electrical and mechanical behaviour of the piezoelectric transducer 100.
The mechanical vibration of the piezoelectric transducer 100 is modelled by the inductive reactance of the inductor 120, when the frequency of the electric signal driving the piezoelectric transducer 100 is at, or near, the resonant frequency of the piezoelectric transducer 100.
Internal losses associated with the operation of the piezoelectric transducer 100, such as mechanical damping and dielectric losses within the piezoelectric crystal of the transducer 100 are modelled by the resistor 130. The resistance value of the resistor 130 is linked to the quality factor (or Q-factor) of the resonance of the piezoelectric transducer 100, which affects the amplitude and the sharpness of the resonance peak in the transducer's 100 frequency response.
Capacitive mechanical and electrical characteristics of the piezoelectric transducer 100 are modelled by the in-series capacitor 140.
Inherent dielectric properties of the material forming the piezoelectric transducer, e.g., due to the structure of the piezoelectric material between electrodes of the transducer 100 are modelled by the in-parallel capacitor 150. This inherent "parallel" capacitance significantly influences the resonance behaviour of the piezoelectric transducer 100, for example, by affecting the total impedance of the circuit at resonance when combined with the inductive and resistive elements (as modelled by the inductor 120 and the resistor 130).
As an example, the circuit of Figure 5 may be suitable for modelling a typical piezoelectric transducer 100 with a resonance frequency of approximately 3 MHz, by providing the inductor 120 with an inductance of 3 µH, the resistor 130 with a resistance of 4 Ω, the in-series capacitor 140 with a capacitance of 938 pF, and the in-parallel capacitor 150 with a capacitance of 1 nF.
Fig. 6 shows a portion of a conventional driving circuit 200 for driving a piezoelectric transducer 100 using an H-bridge. The H-bridge is defined by four switches 210, 220, 230, 240 arranged in an 'H-shaped' arrangement around the piezoelectric transducer 100. In the example shown in Fig. 6, the four switches 210, 220, 230, 240 are each defined by a respective MOSFET. The H-bridge of Fig. 6 is useful for rapidly changing the polarity of a voltage applied to the piezoelectric transducer 100, thereby driving piezoelectric vibrations in the transducer 100.
H-bridge circuits such as the one depicted in Fig. 6 may face challenges in the context of a user device such as the aerosol-generating apparatus 1 described herein.
For example, high-frequency switching of the four (MOSFET) switches 210, 220, 230, 240 may result in significant power and heat dissipation, generating considerable amounts of heat. This heat can degrade component performance over time and shorten the lifespan of the whole H-bridge, including the piezoelectric transducer 100. Moreover, the power dissipation may represent an undesirable inefficiency in the circuit performance of the H-bridge.
There may also be a risk of a latch-up type short-circuit in which one or more parts of the H-bridge circuit become uncontrollably conductive, thereby compromising the circuit's reliability. In the extreme, latch-up can lead to total circuit failure.
Electromagnetic interference may also be a concern when considering the implementation of a H-bridge. The rapid switching inherent in the operation of the four (MOSFET) switches 210, 220, 230, 240 can generate interference that can disrupt the operation of other electronic components/devices in the vicinity of the H-bridge.
Additionally, the operation of the piezoelectric transducer 100 (or indeed any component having an inductive load), can lead to high-voltage spikes in the current flowing through the circuit. Such spikes risk causing severe damage to the transistors used to embody the four MOSFET switches 210, 220, 230, 240 of the H-bridge shown in Fig. 6.
Furthermore, to induce high-frequency (e.g., ultrasonic) vibrations in the piezoelectric transducer 100, very precise and potentially complex timing control of the H-bridge is required. In particular, if both the first and second switches 210, 220, both the first and third switches 210, 230, both the second and fourth switches 220, 240 or both the third and fourth switches 230, 240 are open at the same time, there is a significant risk of shoot-through, or crossover, current that risks damaging the switches as the shoot-through current passes through and reduces the power efficiency of the H-bridge.
Fig. 7 shows an example of an improved driving circuit 300 for driving a piezoelectric transducer 100 using a single (MOSFET) switch 310.
The driving circuit 300 of Fig. 7 comprises a gate power source 320 configured to controllably apply a voltage to the gate of the MOSFET switch 310 to controllably open and close the MOSFET switch 310. The gate power source 320 may be connected to a clock, or may be an oscillator circuit so as to cyclically open and close the MOSFET switch 310 at a selected frequency.
The driving circuit 300 further comprises a driving power source 330 configured to supply power through the driving circuit 300. When the MOSFET switch 310 is closed, the current supplied by the driving power source 300 bypasses the piezoelectric transducer and flows into the source of the MOSFET switch 310 and out from the drain of the MOSFET switch 310 to ground. The driving power source 330 may be the power supply 2 discussed above in relation to Fig. 1.
When the MOSFET switch 310 is open, the current supplied by the driving power source 300 flows through the piezoelectric transducer 100 to ground, thereby inducing vibration in the piezoelectric transducer.
Application of a current to a piezoelectric transducer 100 induces a mechanical response in the transducer 100. Typically, the current applied to the piezoelectric transducer 100 is an alternating current so as to induce oscillatory vibrations in the piezoelectric transducer 100. Upon application of a current in a first polarity, opposite faces of the piezoelectric crystal of the transducer 100 respond by expanding, or bulging, outwards to define respective convex surfaces. Conversely, upon application of current in a second polarity opposite to the first polarity, the opposite faces of the piezoelectric crystal of the transducer 100 respond by contracting, or drawing, inwards to define respective concave surfaces. In the context of an aerosol-generating apparatus 1, it may be advantageous to only drive the piezoelectric transducer 100 in the first polarity so that physical contact between the transducer 100 and the at least some of the liquid precursor 6 can be maintained. Maintaining this physical contact improves the power efficiency of the inducement of cavitation in the liquid precursor 6, and therefore improves the efficiency of the generation of the aerosol. To this end, the driving signal provided by the driving power source 330 is preferably a direct current power source oscillating, at the piezoelectric transducer 100, between a maximum amplitude and a minimum (zero) amplitude with a frequency corresponding to the switching frequency of the MOSFET switch 310.
The driving circuit 300 may further comprise an inductor 350 connected in series with the piezoelectric transducer. The inductor 350 is arranged and configured with an inductance suitable for smoothing the current profile of the signal provided by the driving power source 330 such that the piezoelectric transducer 100 is not subjected to abrupt step-changes in the voltage and current flowing therethrough. This smoothing of the current profile consequently reduces the risk of damage to the piezoelectric transducer by reducing the risk of harmful voltage spikes.
The driving circuit 300 may further comprise one or more resistors 360, 370, 380 configured to limit the current flowing through the driving circuit.
Referring to Fig. 8 there is provided an aerosol generating system 400 that comprises a first tank 410 containing a first liquid aerosol precursor and a second tank 420 containing a second liquid aerosol precursor. In the example shown in Fig. 8, the first liquid aerosol precursor in the first tank 410 comprises a nicotine formulation and the second liquid aerosol precursor in the second tank 420 comprises a flavour formulation, i.e., a nicotine free formulation.
The aerosol generating system further comprises an aerosol generation unit 430 in fluid communication with the first tank 410 and the second tank 420 such that the first liquid aerosol precursor is communicated from the first tank 410 to the aerosol generation unit 430 and such that the second liquid aerosol precursor is communicated from the second tank 420 to the aerosol generation unit 430.
In the example shown in Fig. 8, the aerosol generation unit 430 comprises a first aerosol generator 431 and a second aerosol generator 432, each of which comprises a piezoelectric transducer 100 and a drive circuit 300 as described above.
The first aerosol generator 431 is in fluid communication with the first tank 410 in order to communicate the first liquid aerosol precursor from the first tank 410to the first aerosol generator 431, and in particular to the aerosolization surface of the piezoelectric transducer of the first aerosol generator 431, for example by way of a wick.
The second aerosol generator 432 is in fluid communication with the second tank 420 in order to communicate the second liquid aerosol precursor from the second tank 420 to the second aerosol generator 432, and in particular to the aerosolization surface of the piezoelectric transducer of the second aerosol generator 432, for example by way of a wick.
The aerosol generation unit 430, and in particular, the first aerosol generator 431 and the second aerosol generator 432 are communicatively linked to a controller 440 adapted to control the activation of the first aerosol generator 431 and the second aerosol generator 432 according to the methods described below. In particular, the controller 440 is adapted to control the first aerosol generator 431 and the second aerosol generator 432 in order to adjust the ratio of first aerosol to second aerosol within an aerosol mixture generated by the aerosol generation unit 430.
The aerosol generating system 400 comprises an inhalation sensor 450 communicatively linked to the controller and adapted to sense an inhalation of the user. The controller 440 is adapted to activate the first aerosol generator 431 and the second aerosol generator 432 in response to an inhalation of the user sensed by the inhalation sensor 450.
In addition, the inhalation sensor 450 is adapted to determine the strength of a given inhalation of the user. For example, the inhalation sensor 450 may be adapted to sense a relative change in pressure generated by the user inhaling and this relative change in pressure may be used to determine the relative strength of an inhalation compared to an expected change in pressure caused by an average inhalation strength.
The controller 440 is further adapted to a control signal to cause the aerosol generation unit 430 to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation as determined by the inhalation sensor 450.
Referring to Fig. 9, there is provided a method 4000 for controlling the aerosol generating system 400 shown in Fig. 8.
The method 4000 begins in step 4010 by obtaining an inhalation strength of the user. The inhalation strength of the user may be obtained, for example, by way of the inhalation sensor 450 shown in Fig. 8. Step 4010 may occur during an initial period of the total inhalation period. The initial period may be of the order of microseconds in duration, for example the first 10µs of the inhalation.
In step 4020, the ratio of the amount of first aerosol to be generated to the amount of second aerosol to be generated for the remainder of the total inhalation period is adjusted according to the obtained inhalation strength.
After the inhalation has finished, the method 4000 may return to step 4010 in preparation for a subsequent inhalation of the user.
Referring to Fig. 10, there is provided an example method 4100 for adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation, i.e., for performing step 4020 of the method shown in Fig. 9.
The method 4100 begins in step 4110 by comparing the obtained inhalation strength (for example, the inhalation strength obtained in step 4010 of the method 4000 in Fig. 9) to an inhalation strength threshold. In particular, the obtained inhalation strength is compared to two inhalation strength thresholds, an upper inhalation strength threshold and a lower inhalation strength threshold.
If the obtained inhalation strength is greater than or equal to the upper inhalation strength threshold, the method progresses to step 4120 and the ratio of the first aerosol generated to the second aerosol generated is decreased.
Step 4120 may be performed according to a number of different operations. For example, where the first aerosol generator 431 and the second aerosol generator comprise piezoelectric transducers, the driving parameters of the piezoelectric transducer of the first aerosol generator 431 may be adjusted to reduce the amount of first aerosol generated in response to the inhalation. For example, the first driving power and/or the first driving duty cycle of the piezoelectric transducer of the first aerosol generator 431 may be reduced in order to reduce the amount of first aerosol generated in response to the inhalation.
Correspondingly, the second driving power and/or the second driving duty cycle of the piezoelectric transducer of the second aerosol generator 432 may be increased in order to increase the amount of second aerosol generated in response to the inhalation in order to make up for the reduction in the amount of first aerosol generated.
Alternatively, the activation of the first aerosol generator 431 may be delayed with respect the activation of the second aerosol generator 432 in order to generate first aerosol for a shorter period of time during the inhalation period.
If the obtained inhalation strength is less than or equal to the lower inhalation strength threshold, the method progresses to step 4130 and the ratio of the first aerosol generated to the second aerosol generated is increased.
Step 4130 may be performed according to a number of different operations. For example, where the first aerosol generator 431 and the second aerosol generator comprise piezoelectric transducers, the driving parameters of the piezoelectric transducer of the first aerosol generator 431 may be adjusted to increase the amount of first aerosol generated in response to the inhalation. For example, the first driving power and/or the first driving duty cycle of the piezoelectric transducer of the first aerosol generator 431 may be increased in order to increase the amount of first aerosol generated in response to the inhalation.
Correspondingly, the second driving power and/or the second driving duty cycle of the piezoelectric transducer of the second aerosol generator 432 may be reduced in order to reduce the amount of second aerosol generated in response to the inhalation in order to make up for the increase in the amount of first aerosol generated.
Alternatively, the activation of the second aerosol generator 431 may be delayed with respect the activation of the first aerosol generator 432 in order to generate second aerosol for a shorter period of time during the inhalation period.
Referring to Fig. 11, there is provided a schematic representation of the method 4000 shown in Fig. 9 and the method 4100 shown in Fig. 10.
In particular, Fig. 11 shows a graph 4200 depicting the relative inhalation strengths of three consecutive inhalations of a user of the aerosol generating system 400. Fig. 11 further shows a graph 4300 depicting the ratio of first aerosol to second aerosol generated in response to each inhalation depicted in graph 4200.
The first inhalation 4210 depicted in graph 4200 has an inhalation strength that lies between the upper inhalation strength threshold 4202 and the lower inhalation strength threshold 4204. The first inhalation 4210 is an example of an average strength inhalation.
Correspondingly, the first inhalation 4301 depicted in graph 4300 shows an even ratio between the first aerosol 4310 and the second aerosol 4320 generated in response to the average strength first inhalation 4210 in graph 4200.
The second inhalation 4220 depicted in graph 4200 has an inhalation strength that is less than the lower inhalation strength threshold 4204. The second inhalation 4220 is an example of a weak inhalation.
Correspondingly, the second inhalation 4302 depicted in graph 4300 shows an increase in the ratio of the first aerosol 4330 to the second aerosol 4340 generated in response to the weak second inhalation 4220 in graph 4200.
The third inhalation 4230 depicted in graph 4200 has an inhalation strength that lies above the upper inhalation strength threshold 4202. The third inhalation 4230 is an example of a strong inhalation.
Correspondingly, the third inhalation 4303 depicted in graph 4300 shows a decrease in the ratio of the first aerosol 4350 to the second aerosol 4360 generated in response to the strong third inhalation 4230 in graph 4200.

Claims

An aerosol generating system comprising:
a first tank for containing a first liquid aerosol precursor;

a second tank for containing a second liquid aerosol precursor;

an aerosol generation unit in fluid communication with the first and second tanks for generating a first aerosol from the first liquid aerosol precursor and generating a second aerosol from the second liquid aerosol precursor in response to an inhalation of a user;

an inhalation sensor arranged to determine a strength of the inhalation; and

a electrical circuitry adapted to:
generate a control signal to cause the aerosol generation unit to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation.
The aerosol generating system claimed in claim 1, wherein adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation comprises:
comparing the strength of the inhalation to an upper inhalation strength threshold; and

if the strength of the inhalation is greater than or equal to the upper inhalation strength threshold, decreasing the ratio of the first aerosol generated to the second aerosol generated.
The aerosol generating system claimed in any of claims 1 to 2, wherein adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation comprises:
comparing the strength of the inhalation to a lower inhalation strength threshold; and

if the strength of the inhalation is less than or equal to the lower inhalation strength threshold, increasing the ratio of the first aerosol generate to the second aerosol generated.
The aerosol generating system claimed in any preceding claim, wherein the aerosol generating unit comprises a first piezoelectric transducer for generating the first aerosol from the first liquid aerosol precursor and a second piezoelectric transducer for generating the second aerosol from the second liquid aerosol precursor.
The aerosol generating system claimed in claim 4, wherein the device further comprises a drive circuit adapted to:
drive the first piezoelectric transducer according to a first set of driving parameters; and

drive the second piezoelectric transducer according to a second set of driving parameters.
The aerosol generating system claimed in claim 5, wherein generating the control signal to cause the aerosol generation unit to adjust a ratio between the first aerosol generated in response to the inhalation and the second aerosol generated in response to the inhalation comprises:
generating a control signal to cause the driving circuit to adjust one or more of the first set of driving parameters and/or one or more of the second set of driving parameters.
The aerosol generating system claimed in any of claims 5 to 6, wherein the first set of driving parameters comprises one or more of:
a first driving frequency;

a first driving duty cycle; and

a first driving power; and
wherein the second set of driving parameters comprises one or more of:
a second driving frequency;

a second driving duty cycle; and

a second driving power.
The aerosol generating system claimed in claim 7, when dependent on claim 2, wherein decreasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of:
decreasing the first driving duty cycle;

decreasing the first driving power;

increasing the second driving duty cycle; and

increasing the second driving power.
The aerosol generating system claimed in any of claims 7 to 8, when dependent on claim 3, wherein increasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of:
increasing the first driving duty cycle;

increasing the first driving power;

decreasing the second driving duty cycle; and

decreasing the second driving power.
The aerosol generating system as claimed in any preceding claim, wherein generating the control signal to cause the aerosol generation unit to adjust a ratio between the first aerosol generated in response to the inhalation and the second aerosol generated in response to the inhalation comprises:
delaying the generation of one of the first aerosol and the second aerosol with respect to the generation of the other of the first aerosol and the second aerosol, thereby reducing an aerosol generation time for one of the first aerosol and the second aerosol.
The aerosol generating system as claimed in claim 10, when dependent on claim 2, wherein decreasing the ratio of the first aerosol generated to the second aerosol generated comprises delaying the generation of the first aerosol with respect to the generation of the second aerosol, thereby reducing an aerosol generation time for the first aerosol.
The aerosol generating system as claimed in any of claims 10 to 11, when dependent on claim 3, wherein increasing the ratio of the first aerosol generated to the second aerosol generated comprises delaying the generation of the second aerosol with respect to the generation of the first aerosol, thereby reducing an aerosol generation time for the second aerosol.
The aerosol generating system claimed in any preceding claim, wherein the first liquid aerosol precursor is a nicotine formulation.
The aerosol generating system claimed in any preceding claim, wherein the second liquid aerosol precursor is:
a flavour formulation; or

a plain formulation.
A computer-implemented method for controlling an aerosol generating system, the aerosol generating system comprising:
a first tank for containing a first liquid aerosol precursor;

a second tank for containing a second liquid aerosol precursor;

an aerosol generation unit in fluid communication with the first and second tanks for generating a first aerosol from the first liquid aerosol precursor and generating a second aerosol from the second liquid aerosol precursor in response to an inhalation of a user; and

an inhalation sensor arranged to determine a strength of the inhalation; and

wherein the computer-implemented method comprises:
obtaining the strength of the inhalation from the inhalation sensor; and

generating a control signal to cause the aerosol generation unit to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation.