WO2023222598A1

WO2023222598A1 - Profile selection for aerosol-generating device

Info

Publication number: WO2023222598A1
Application number: PCT/EP2023/062966
Authority: WO
Inventors: Gennaro CAMPITELLI; Bruno Christian Joseph CHASSOT
Original assignee: Philip Morris Products S.A.
Priority date: 2022-05-16
Filing date: 2023-05-15
Publication date: 2023-11-23

Abstract

An aerosol-generating device for generating an aerosol from an aerosol-generating article comprising an aerosol-forming substrate. The aerosol-generating device is configured to generate the aerosol during a usage session comprising a usage session start and a usage session end. The aerosol-generating device comprises a heater assembly for heating the aerosol-forming substrate. The aerosol-generating device further comprises a power supply configured to supply power to the heater assembly. The aerosol-generating device further comprises control circuitry comprising a memory in which a plurality of predetermined heating profiles are stored. At least one of the plurality of predetermined heating profiles has a first duration and at least one of the predetermined heating profiles has a second duration different to the first duration. The control circuitry is configured to detect a trigger condition and select a predetermined heating profile for use during the usage session based on the detected trigger condition. The selected predetermined heating profile has either the first duration or the second duration. The trigger condition is dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device.

Description

PROFILE SELECTION FOR AEROSOL-GENERATING DEVICE

The present disclosure relates to an aerosol-generating device, an aerosol-generating system comprising the aerosol-generating device and a method of controlling power supplied to a heater assembly of an aerosol-generating system.

Aerosol-generating systems configured to generate an aerosol from an aerosol-forming substrate, such as a tobacco-containing substrate, are known in the art. Many known aerosolgenerating systems generate aerosol by the application of heat to the substrate by a heater assembly. In electrically operated aerosol-generating systems, heat is applied to the substrate when the heater assembly is supplied with power from a power supply. The generated aerosol can then be inhaled by a user of the system as part of a user puff. A usage session of the aerosolgenerating system typically comprises a plurality of user puffs.

Many aerosol-generating systems comprise a controller configured to control the supply of power to the heater assembly according to a predetermined heating profile. The predetermined heating profile is typically optimized such that a consistent aerosol is generated throughout a usage session assuming a specific puff behaviour is followed during that usage session. A user puff behaviour may be characterised, for example, by a puff frequency throughout the usage session or an interval between subsequent puffs throughout the usage session.

If the specific puff behaviour for which the predetermined heating profile is optimized is not followed by the user, then the aerosol generated throughout the usage session may be inconsistent. For example, the quantity of the aerosol or the chemical composition of the aerosol may differ significantly from user puff to user puff.

In one particular example, it has been found that a first subset of the users of aerosolgenerating systems prefer a first puff behaviour comprising a puff interval of about 20 seconds and a second subset of users of aerosol-generating systems prefer a second puff behaviour comprising a longer puff interval of about 40 seconds. If the second puff behaviour is followed during a usage session but the predetermined heating profile implemented by an aerosolgenerating system is optimized for the first puff behaviour, then the aerosol that is generated throughout the usage session may be inconsistent.

The longer puff interval of the second subset of users is a puff behaviour that is similar to a typical behaviour of a smoker of Kretek conventional cigarettes.

It would be desirable to provide an aerosol-generating system in which aerosol generation is consistent for different puff behaviours followed during a usage session. It would be desirable to provide an aerosol-generating system that is optimizable for users who are previously smokers of either or both of Kretek and non-Kretek conventional cigarettes.

In a first aspect there is provided an aerosol-generating device. The aerosol-generating device may be for generating an aerosol from an aerosol-generating article. The aerosolgenerating article may comprise an aerosol-forming substrate. The aerosol-generating device may be configured to generate the aerosol during a usage session. The usage session may comprise a usage session start. The usage session start may comprise a usage session end.

The aerosol-generating device may comprise a heater assembly for heating the aerosolforming substrate.

The aerosol-generating device may comprise a power supply. The power supply may be configured to supply power to the heater assembly.

The aerosol-generating device may comprise control circuitry. The control circuitry may comprise a memory. A plurality of predetermined heating profiles may be stored in the memory. At least one of the plurality of predetermined heating profiles may have a first duration. At least one of the plurality of predetermined heating profiles may have a second duration different to the first duration.

The control circuitry may be configured to detect a trigger condition. The control circuitry may be configured to select a predetermined heating profile for use during the usage session. The selection may be based on the detected trigger condition.

The selected predetermined heating profile may have either the first duration or the second duration. The trigger condition may be dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device.

A predetermined heating profile having the first duration may be optimized for a first puff behaviour. A predetermined heating profile having the second duration may be optimized for a second puff behaviour that is different to the first puff behaviour. The control circuitry being configured to selected a predetermined heating profile for use during the usage session may advantageously mean that an appropriate predetermined heating profile may be selected by the control circuitry for a particular use scenario in which a particular puff behaviour is followed. In this way, a consistent aerosol may be generated during a usage session for different puff behaviours. A user may advantageously follow one of a variety of puff behaviours during a usage session using the same aerosol-generating device and the same aerosol-forming substrate.

The trigger condition being dependent on a user interaction with the aerosol-generating device may mean that the trigger condition is dependent on a user puff behaviour (puffing on the device being a user interaction). In such cases, the control circuitry may be configured to determine a user puff behaviour. The control circuitry may then be configured to use the determined user puff behaviour to select a predetermined heating profile having the first or second duration.

When the trigger condition is dependent on a user puff behaviour, the control circuitry may advantageously select a predetermined heating profile having the first or second duration automatically.

Alternatively or additionally, the trigger condition being dependent on a user interaction with the aerosol-generating device may mean that the trigger condition is dependent on the output, state or user manipulation of one or more user interface elements of the aerosol-generating device. The one or more user interface elements may comprise a button or switch, for example. The control circuitry may be configured to use a state of the one or more user interfaces to select a predetermined heating profile having the first or second duration.

Alternatively or additionally, the trigger condition may be dependent on a property of an aerosol-generating article used with the device. The control circuitry may be configured to detect the property of the aerosol-generating article used with the device. The control circuitry may be configured to use the detected property to select a predetermined heating profile having the first or second duration. Preferably, the property that the control circuitry is configured to detect relates to a property of an identifier of the aerosol-generating article, such as a bar code or a taggant.

When the trigger condition is dependent on one or more user interface elements, or on a property of an aerosol-generating article used with the device, the selection of a predetermined heating profile having the first or second duration may advantageously allow a user to decide which heating profile they prefer based on their typical puffing behaviour. In particular, a user may use the one or more user interface elements to choose the duration of the predetermined heating profile or may choose an aerosol-generating article having a particular property, preferably a particular identifier.

In all of the above examples, basing the selection of a duration of the predetermined heating profile on the trigger condition may advantageously allow a user to follow one of a variety of user puff behaviours during a usage session using the same aerosol-generating device and the same aerosol-forming substrate.

As user herein, a “user puff behaviour” may refer to any property of a user puff that may differ between different usage patterns. For example, a user puff behaviour may be defined by at least one of: a puff frequency, a puff interval, a puff strength, a puff length, a number of puffs taken, a quantity of aerosol generated per puff or a quantity of aerosol generated. One or more of these properties may differ between a “first” user puff behaviour and a “second” user puff behaviour. Preferably, the user puff behaviour may refer to puff frequency or puff interval.

The control circuitry may be configured to control the supply of power to the heater assembly according to the selected predetermined heating profile having either the first duration or the second duration.

Both the first duration and the second duration may be at least 1 minute, preferably at least 2 minutes, preferably at least 3 minutes. In this way, predetermined heating profiles of the first and second durations last for a plurality of user puffs during a usage session.

The first duration may be longer than the second duration.

A first user puff behaviour may comprise a puff interval that is longer, and a puff frequency that is lower, than a second user puff behaviour. It has been found that, regardless of whether a user follows a first user puff behaviour or a second user puff behaviour, the user will typically perform a similar number of puffs during a usage session. So, the overall length of the usage session may be longer if the user follows the first user puff behaviour than if the user follows the second user puff behaviour. A predetermined heating profile having the first (longer) duration may advantageously be selected when the first user puff behaviour is to be followed and a predetermined heating profile having the second (shorter) duration may advantageously be selected when the second user puff behaviour is to be followed.

The first duration may be at least 30% longer than the second duration, preferably at least 40% longer, preferably at least 50% longer, preferably at least 75% longer.

The first duration may be longer than 5 minutes, preferably longer than 6 minutes, preferably longer than 8 minutes.

The first duration may be no more than 18 minutes, preferably no more than 15 minutes, preferably no more than 12 minutes.

The second duration may be no more than 8 minutes, preferably no more than 6 minutes, preferably no more 4 minutes.

The duration of the usage session may be dependent on the duration of the selected predetermined heating profile. As above, it has been found that users typically perform a similar number of puffs regardless of other features of the puff behaviour such as puff interval and puff frequency. So, a user following a first user puff behaviour having, for example, a longer interval or lower puff frequency, may perform the desired number of puffs in a longer time than user following the second user puff behaviour. As such, it may be advantageous for the usage session length to change according to the determined user puff behaviour and for the duration of the selected predetermined heating profile to correspond to the changing time in which a user performs the desired number of puffs.

The maximum duration of the usage session may be at least 5 minutes, preferably at least 6 minutes, preferably at least 8 minutes, preferably at least 10 minutes, preferably at least 12 minutes if the selected predetermined heating profile has the first duration.

The maximum duration of the usage session may be no more than 10 minutes, preferably no more than 8 minutes, preferably no more than 7 minutes, preferably no more than 6 minutes if the selected predetermined heating profile has the second duration.

The plurality of predetermined heating profiles may comprise a first predetermined heating profile having the first duration and a second predetermined heating profile having the second duration.

The plurality of predetermined heating profiles may comprise a first subset of predetermined heating profiles, each profile in the first subset having the first duration. The plurality of predetermined heating profiles may comprise a second subset of predetermined heating profiles, each profile in the second subset having the second duration.

Each predetermined heating profile may comprise one or more target temperatures. When the control circuitry is configured to supply power to the heater assembly according to a particular predetermined heating profile, the control circuitry may be configured to heat the heater assembly with reference to the one or more target temperatures. The one or more target temperatures may advantageously be chosen to ensure a consistent amount of aerosol is generated throughout at least the second period of the usage session. For example, an initial target temperature of a predetermined heating profile may be high to ensure the aerosol-forming substrate reaches operation temperature. Subsequent target temperatures of the predetermined heating profile may be lower than the initial target temperature to avoid overheating the aerosolforming substrate.

Preferably, the first predetermined heating profile may be configured such that a mean average of the target temperature throughout the duration of the first predetermined heating profile is lower than a mean average of the target temperature throughout the duration of the second predetermined heating profile.

Preferably, the usage session comprises a plurality of puffs. Even more preferably, a usage session comprises more than four user puffs, even more preferably more than five user puffs, even more preferably more than six user puffs, even more preferably more than seven user puffs, even more preferably more than eight user puffs, even more preferably more than nine user puffs, even more preferably more than ten user puffs, even more preferably more than eleven user puffs, even more preferably more than twelve user puffs.

The usage session end may correspond to the end of the selected predetermined heating profile.

The aerosol-generating device may comprise a detection assembly. The detection assembly may be configured to detect at least one of a user interaction with the aerosolgenerating device, or a property of an aerosol-generating article used with the device.

When the detection assembly is configured to detect a property of an aerosol-generating article used with the device, the detected property may preferably not be a property of an aerosolforming substrate contained in the aerosol-generating article. Instead, the detected property may be another feature of the aerosol-generating article. In particular, the aerosol-generating article may comprise an identifier such as a bar code or a taggant. The detector may be configured to detect the identifier. The control circuitry may be configured to distinguish between different identifiers. The trigger condition may relate to the detected identifier. The control circuitry may be configured to select a predetermined heating profile having the first duration or the second duration during the usage session based on the detected identifier.

The aerosol-generating device may comprise a device housing defining a cavity for receiving the aerosol-generating article. The cavity may be configured to receive at least a portion of the aerosol-generating article comprising the aerosol-forming substrate. The detection assembly may be configured to detect a property of aerosol-generating article received in the cavity, preferably an identifier of the aerosol-generating article.

The detector assembly may be configured to distinguish between a first identifier and a second identifier that is different to the first identifier. An aerosol-generating article used with the device may comprise the first or second identifier. The control circuitry may be configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether the first or second identifier is detected. The control circuitry may be configured to select a predetermined heating profile having the first duration when the first identifier is detected. The control circuitry may configured to select a predetermined heating profile having the second duration when the second identifier is detected.

In this way, a user of the aerosol-generating device may advantageously choose to use the device with an aerosol-generating article comprising a property that is related to the user’s preferred user puff behaviour during a usage session. For example, if a user prefers to follow a first user puff behaviour, the user may select an aerosol-generating article comprising a first property, in particular a first identifier, to use with the device. If a user prefers to follow a second user puff behaviour that is different to the first user puff behaviour, the user may select an aerosolgenerating article comprising a second property, in particular a second identifier, that is different to the first property or identifier, to use with the device.

An aerosol-generating article comprising the first identifier may comprise substantially the same type of aerosol-forming substrate as an article comprising the second identifier. For example, the chemical composition of the aerosol-forming substrate may be substantially the same for an aerosol-generating comprising a first identifier as for an aerosol-generating article comprising the second identifier. So, the control circuitry being configured to select of a predetermined heating profile of the first or second duration may be to account for a user’s preferred puff behaviour rather than to account for differences in the type of aerosol-forming substrate being used with the device.

Herein, the aerosol-forming substrate being “substantially the same” means that the aerosol-forming substrate of a first aerosol-generating article comprising a first identifier has identical properties to the aerosol-forming substrate of a second aerosol-generating article comprising a second identifier other than for differences arising from manufacturing tolerances.

As used herein with reference to the present invention, the term “taggant” refers to a chemical or physical marker added to a component, the presence of which may be detected by a suitable detector enabling the component to be identified. Physical taggants can take many different forms but are typically microscopic in size, included at low levels, and simple to detect. The taggant may comprise uniquely encoded material.

The taggant may be any taggant. For example, the taggant may comprise a photoluminescent material having an emission half-life of between 50 microseconds and 1000 microseconds after photoexcitation of the photoluminescent material.

The taggant may be provided on any component on a downstream section of the aerosolgenerating article. For example, the taggant may be provided on one or more of an adhesive, a wrapper, a tipping paper, a filter plug, a susceptor, a mouthpiece filter, a space tube, or a flavourant where present. The taggant may be provided on more than one component. This may advantageously make detection of the taggant by the detector more reliable.

The control circuitry may be configured to determine a user puff behaviour during a first period of the usage session.

The control circuitry may be configured to select a predetermined heating profile having either the first duration or the second duration dependent on the determined user puff behaviour.

The control circuitry may be configured to control the supply of power to the heater assembly according to the selected predetermined heating profile during a second period of the usage session.

The control circuitry being configured to use the determined user puff behaviour of the first period to select one of the plurality of predetermined heating profiles advantageously means that a predetermined heating profile that has a duration that is optimized for the determined puff behaviour during the first period can be selected and applied during the second period. In this way, a consistent aerosol may be generated throughout the second period of the usage session for different puff behaviours.

It has been found that users of an aerosol-generating system tend to maintain a consistent puff behaviour throughout a usage session and so it may be assumed that the determined puff behaviour of the first period will be maintained throughout the second period of the usage session.

The first period of the usage session may comprise one or more user puffs. Preferably, the first period of the usage session comprises a plurality of user puffs.

The control circuitry may be configured to determine the user puff behaviour based on one or more user puffs of the first period of the usage session. Preferably, the control circuitry is configured to assess the determined user puff behaviour over a plurality of user puffs during the first period.

The control circuitry may be configured to determine a mean average puff behaviour for a plurality of user puffs during the first period. It has been found that, while a user’s puff behaviour may vary puff to puff, the puff behaviour may be substantially consistent throughout a usage session for a plurality of puffs. As such, a mean average of the puff behaviour may typically be substantially uniform throughout a usage session and so a user’s puff behaviour may be effectively characterised based on an average puff behaviour during the first period. A mean average puff behaviour may reduce the effect of variance in the puff behaviour on a puff to puff basis.

The determined user puff behaviour during the first period may relate to at least one of: a puff frequency, a puff interval, a puff strength, a puff length, a number of puffs taken, a quantity of aerosol generated per puff or a quantity of aerosol generated during the first period.

Preferably, the determined user puff behaviour during the first period is at least one of a mean average puff frequency, a mean average puff interval, a mean average puff strength, a mean average puff length or a mean average quantity of aerosol generated per puff.

The first period may comprise a first period start and a first period end. The first period end may be at least 20 seconds after the first period start, preferably the first period end may be at least 30 seconds after the first period start, preferably the first period end may be at least 40 seconds after the first period start, preferably the first period end may be at least 50 seconds after the first period start, preferably the first period end may be at least 75 seconds after the first period start, preferably the first period end may be at least 90 seconds after the first period start. The first period start may be not more than 150 seconds, preferably not more than 140 seconds, preferably not more than 130 seconds, preferably not more than 120 seconds, preferably not more than 110 seconds from the first period start.

As above, the first period may comprise one or more puffs, preferably a plurality of puffs. So, the duration between the first period start and the first period end may be long enough to comprise one or more puffs, preferably long enough to comprise a plurality of puffs. Of course, the number of puffs in a given time may depend on the puff behaviour followed by a user of the device. In any case, at least 20 seconds between the first period start and first period end may be more than enough time to comprise a single puff. The longer the first period, the more puffs that are likely to be contained within the first period. So, the longer values disclosed above for the time between the first period end and the first period start may be preferable when the determined user puff behaviour is based on a plurality of user puffs and, particularly, when the determined user puff behaviour is a mean average user puff behaviour.

The first period end may be a predetermined time after the first period start. The predetermined time may be at least 20 seconds, preferably at least 30 seconds, preferably at least 40, preferably at least 50 seconds, preferably at least 75 seconds, preferably at least 90 seconds. The predetermined time may be not more than 150 seconds, preferably not more than 140 seconds, preferably not more than 130 seconds, preferably not more than 120 seconds, preferably not more than 110 seconds.

The control circuitry may be configured to monitor the number of puffs that have occurred during the first period. The control circuitry may be configured such that the first period end is when the control circuitry has detected that a predetermined number of puffs have occurred during the first period. The predetermined number of user puffs during the first period may be at least 2 puffs, preferably at least 3 puffs. An advantage of the first period end being dependent on when a predetermined number of puffs have been taken is that the first period is then dynamic. If a user is following a puff behaviour in which the interval between puffs is low, the first period may be short meaning and the predetermined heating profile for the second period may advantageously be selected and followed earlier in the usage session. However, if a user is following a slow puff haviour with a longer interval between puffs, a dynamic first period may advantageously extend to be long enough to achieve a reliable measure of the user puff behaviour.

Preferably, the first period start corresponds to the usage session start. In other words, the first period of the usage session is an initial period of the usage session.

The second period of the usage session may comprise a plurality of user puffs. The second period of the usage session may preferably comprise more than three, preferably more than five, preferably more than seven, preferably more than eight, preferably more than nine user puffs. Preferably, the controller is configured to control the supply of power to the heater assembly during each of the puffs of the second period according to the selected predetermined heating profile.

The second period may comprise a second period start and a second period end.

The second period start may correspond to the first period end. In other words, the second period may immediately follow the first period such that the first and second period are sequential to one another.

The second period end may correspond to the usage session end. In such cases, the control circuitry may be configured to control the supply of power to the heater assembly according to the predetermined heating profile that is selected using the determined user puff behaviour of the first period until the end of the usage session.

The length of the usage session may depend on the length of selected predetermined heating profile. The usage session end may correspond to an end of the selected predetermined heating profile.

It has been found that users typically perform a similar number of puffs regardless of other features of the puff behaviour such as puff interval and puff frequency. So, a user following a first user puff behaviour having, for example, a longer interval or lower puff frequency, may perform the desired number of puffs in a longer time than user following the second user puff behaviour. As such, it may be advantageous for the usage session length to change according to the determined user puff behaviour and selected predetermined heating profile to correspond to the changing time in which a user performs the desired number of puffs.

The control circuitry may be configured to detect a user puff based on signals received from the detector. The control circuitry may be configured to determine the user puff behaviour based on signals received from the detector. For example, the control circuitry may be configured to detect a puff frequency for the first period, or a puff interval, by measuring the time between subsequent detected user puffs. As another example, the control circuitry may be configured to detect the length of detected user puffs or the strength of detected user puffs. When the user puff behaviour is a mean average user puff behaviour, the control circuitry may be configured to detect a plurality of user puffs and determine a mean average user puff behaviour for the detected plurality of user puffs.

The aerosol-generating device may comprise an airflow channel. The airflow channel may extend from an air inlet at least partially defined by a housing of the aerosol-generating device. The airflow channel may extend to an air outlet at least partially defined by a housing the aerosol-generating device. The parameter indicative of a user puff that the detector is configured to detector may be a parameter of air in the airflow channel.

The parameter the detector may be configured to detect may be at least one of flow, pressure, temperature or aerosol quantity.

The heater assembly may comprise a heating element. The heating element may be a resistive heating element. The heating element may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composition materials made of ceramic material and a metallic material. Such composite materials may comprise doped and undoped ceramics.

The aerosol-generating device may comprise a power supply which may be configured to supply current to the resistive heating element.

The heating element may comprise a substrate layer of flexible material. The substrate layer may comprise a thermally stable polymer, preferably polyimide.

The heating element may be arranged on the substrate layer. The heating element may be a resistive heating element. The heating element may contain wire connections configured for being connected with a controller of the aerosol-generating device. The heating element may comprise heating tracks arranged on the substrate layer. The heating tracks may comprise a thermally conductive material, preferably a metal such as stainless steel. The heating tracks may be electrically connected to said wire connections.

The heating element may take other forms. For example, a metallic grid or grids, a flexible printed circuit board, a molded interconnect device (MID), ceramic heater, flexible carbon fibre heater or may be formed using a coating technique such as plasma vapour deposition, on a suitably shaped substrate.

In another example, the heater assembly may comprise one or more inductor coils and the heating element may comprise one or more susceptor elements.

The one or more susceptor elements may be configured to be heatable by an alternating magnetic field generated by the inductor coil or coils. In use, electrical power supplied to an inductor coil (for example, by the above-mentioned power source of the device) results in the inductor coil inducing eddy currents in a susceptor element. These eddy currents, in turn, result in the susceptor element generating heat. The electrical power is supplied to the inductor coil as an alternating magnetic field. The alternating current may have any suitable frequency. The alternating current may preferably be a high frequency alternating current. The alternating current may have a frequency between 100 kilohertz (kHz) and 30 megahertz (MHz). When an aerosolforming substrate is received in the chamber, the heat generated by the susceptor element may heat the aerosol-forming substrate to a temperature sufficient to cause aerosol to evolve from the substrate. The susceptor element is formed of a material having an ability to absorb electromagnetic energy and convert it into heat. By way of example and without limitation, the susceptor element may be formed of a ferromagnetic material, such as a steel.

The detector may comprise a sensor. The sensor may comprise a pressure sensor, a flow sensor, a temperature sensor or an aerosol quantity sensor.

When the heater assembly comprises a heating element, the heating element may form the detector. In such cases, the control circuitry may be configured to detect a user puff based on changes in the temperature of the heating element during the usage session. For example, the control circuitry may be configured to detect a user puff based on a drop in the temperature of the heating element. The control circuitry may be configured to detect a length or a strength of a user puff based on at least one of a length or a magnitude of the drop in the temperature of the heating element.

The control circuitry may be configured to monitor the electrical resistance of the heating element. The electrical resistance of the heating element may preferably be temperature dependent. So, the control circuitry may be configured to determine changes in the temperature of the heating element based on changes in the electrical resistance of the heating element. In particular, the control circuitry may be configured to detect a user puff based on a drop in the resistance of the heater element. The control circuitry may be configured to detect the length or strength of a user puff based on at least one of a length or a magnitude of a drop in the resistance of the heater element.

The control circuitry may be configured to select a predetermined heating profile having the first or second duration based on a comparison of the detected user puff behaviour with a predetermined threshold. The predetermined threshold may be stored in a memory of the control circuitry. In one example, the detected user puff behaviour may be a puff interval during the first period, preferably a mean average puff interval for the first period. The control circuitry may be configured to select the predetermined profile having the first duration if the puff interval is greater than a predetermined threshold for the puff interval. The control circuitry may be configured to select a predetermined profile having the second duration if the puff interval is less than or equal to the predetermined threshold for the puff interval.

In another example, the detected user puff behaviour may be a puff frequency during the first period, preferably a mean average puff frequency for the first period. The control circuitry may be configured to select a predetermined profile having the first duration if the puff frequency is less than or equal to a predetermined threshold for the puff frequency. The control circuitry may be configured to select a predetermined profile having the second duration if the puff frequency is greater than the predetermined threshold for the puff interval.

The control circuitry may be configured to select the first predetermined heating profile if a first user puff behaviour is detected. The control circuitry may be configured to select the second predetermined heating profile if a second user puff behaviour is detected. The first user puff behaviour may be different to the second user puff behaviour.

The control circuitry may be configured to select the first predetermined profile or the second predetermined profile based on a comparison of the detected user puff behaviour with a predetermined threshold. The predetermined threshold may be stored in a memory of the control circuitry. The control circuitry may advantageously use the predetermined threshold to distinguish between the first user puff behaviour and the second user puff behaviour.

The first user puff behaviour may comprise the interval between puffs is greater than 20 seconds, preferably greater than 22 seconds, preferably greater than 24 seconds, preferably greater than 26 seconds, preferably greater than 28 seconds, preferably greater than 30 seconds, preferably greater than 32 seconds, preferably greater than 34 seconds.

Preferably, the interval may be a mean average interval. The mean average interval may be the time between a plurality of subsequent pairs of puffs in the first period divided by the number of pairs of puffs.

The second user puff behaviour may comprise the interval between puffs being less than 34 seconds, preferably less than 32 seconds, preferably less than 30 seconds, preferably less than 28 seconds, preferably less than 26 seconds, preferably less than 24 seconds, preferably less than 22 seconds, preferably less than 20 seconds.

The predetermined threshold for the user puff behaviour stored in the memory may be a threshold for the puff interval or mean average puff interval. The predetermined threshold may be a value between 20 seconds and 34 seconds, preferably between 22 seconds and 32 seconds, preferably between 24 seconds and 30 seconds.

The plurality of predetermined heating profiles may comprise a third predetermined heating profile that is different to the first and second predetermined heating profiles. The control circuitry may be configured to control the supply of power to the heater assembly during the first period according to the third predetermined heating profile.

When the first period comprises a first period start and a first period end and the first period end is a predetermined time after the first period start, the third predetermined heating profile may have the same duration as the predetermined time.

The third predetermined heating profile may comprise a third profile start. The third profile start may correspond to the first period start. In other words, the control circuitry may be configured to control the supply of power to the heater assembly according to the third predetermined heating profile throughout the first period.

The third predetermined heating profile may be shorter than the first and second predetermined heating profile.

The third predetermined heating profile may comprise a target temperature that is higher than a target temperature of the first or second predetermined heating profiles. Preferably, the third predetermined heating profile may comprise a target temperature that is higher than any target temperature of the first or second predetermined heating profiles. This may be particularly advantageous if the control circuitry is configured to control the heater assembly to rapidly increase temperature to a vaporisation temperature during the first period of the usage session.

It may be advantageous for the control circuitry to control the supply of power to the heater assembly in the first period according to the third predetermined heating profile irrespective of the puffing behaviour. This may be particularly preferable when the heater assembly is required to rapidly reach a vaporisation temperature during the first period of the usage session.

At least one of the plurality of predetermined heating profiles may comprise a first portion that is substantially identical to a first portion of another of the plurality of predetermined heating profiles. Each of the plurality of predetermined heating profiles may comprise a first portion that is substantially identical to the first portion of the other predetermined heating profiles of the plurality of predetermined heating profiles. The first portion may be an initial portion of the respective predetermined heating profile.

In a specific example, at least a first portion of the first predetermined heating profile may be substantially identical to a first portion of the second predetermined heating profile. The first portion of the first predetermined heating profile may correspond to the first portion of the second predetermined heating profile. Preferably, the first portion of each of the first and second predetermined heating profiles may be an initial portion of the respective heating profile.

The control circuitry may be configured to control the supply of power to the heater assembly during the first period according to the first portion of one of the plurality of predetermined heating profiles. This may be instead of controlling the supply of power to the heater assembly according to a dedicated third predetermined heating profile for the first period, as described above. The first portion of each of the predetermined heating profiles may comprise a target temperature configured such that the heater assembly rapidly increases in temperature to a vaporisation temperature during the first period of the usage session. It may be advantageous for the heater assembly to be controlled in this manner in the first period irrespective of the puffing behaviour or the selected predetermined heating profile.

One or more of the plurality of predetermined heating profiles may comprise a second portion. The or each second portion may be subsequent to a first portion of the respective predetermined heating profile. The second portion of the or each of the first and second predetermined heating profiles may start immediately following an end of a first portion of the respective predetermined heating profile.

The control circuitry may be configured to control the supply of power to the heater assembly according to the second portion of the selected predetermined heating profile during the second period. The control circuitry may be configured such that the selection to control the supply of power to the heater assembly during the second period comprises selecting to supply power according to a second portion of one of the predetermined heating profiles.

The aerosol-generating device may comprise one or more user interface elements. The detection assembly, which may be configured to detect a user interaction with the aerosolgenerating device, may comprise the one or more user interface elements. In this example, the user interaction may preferably comprise user manipulation of at least one of the one or more user interface elements.

The one or more user interface elements are configured such that at least a first state and a second state may be selectable using the one or more user interface elements by a user of the device. The control circuitry may be configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether the first state or second state of the user interface is selected.

The first state may correspond to a predetermined heating profile having the first duration. The second state may correspond to a predetermined heating profile having the second duration. The control circuitry may be configured to select a predetermined heating profile having the first duration when the first state is selected by the user interface element. The control circuitry may be configured to select a predetermined heating profile having the second duration when the select state is selected by the user interface element.

The one or more user interface elements may comprise one or more buttons or switches.

The aerosol-generating device may be configured for generating aerosol from an aerosolforming substrate comprised in an aerosol-generating article.

As used herein, the term ‘aerosol-forming substrate’ relates to a substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article. The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components. The aerosolforming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. Alternatively, the aerosolforming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerine and propylene glycol.

The aerosol-forming substrate may comprise a gathered crimpled sheet of homogenised tobacco material. As used herein, the term ‘crimped sheet’ denotes a sheet having a plurality of substantially parallel ridges or corrugations. Alternatively or additionally, the aerosol-forming substrate may comprise strands, strips of sheds of homogenised tobacco material. Preferably, the aerosol-forming substrate may comprise cut homogenized tobacco comprising glycerine. The glycerine may be applied to the cut homogenized tobacco. Preferably, the glycerine may be sprayed onto the homogenised tobacco.

The aerosol-generating system may comprise a cartridge containing an aerosol- forming substrate. The cartridge may be receivable in the chamber of the aerosol-generating device. The aerosol-forming substrate may be solid or liquid or comprise both solid and liquid components. Preferably, the aerosol-forming substrate is a liquid.

The aerosol-forming substrate may comprise plant-based material. The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may comprise a tobaccocontaining material containing volatile tobacco flavour compounds, which are released from the aerosol-forming substrate upon heating. Preferably, the aerosol-forming substrate may alternatively comprise a non-tobacco-containing material.

The aerosol-generating article may comprise a wrapper circumscribing the aerosolforming substrate. The aerosol-forming substrate may be a solid aerosol-forming substrate.

The aerosol-generating device may comprise a device housing defining. The device housing may define a cavity. The cavity may be for receiving the aerosol-forming substrate.

The control circuitry may be configured such that the selection of the predetermined heating profile is further based on a detected type of aerosol-forming substrate used with aerosolgenerating device. This would preferably be in addition to the selection being based on the trigger condition.

When the control circuitry is configured so that the selection of predetermined heating profile is further based on a detected type of aerosol-forming substrate, the plurality of predetermined heating profiles may comprise a first subset comprising heating profiles having the first duration and a second subset comprising heating profiles having the second duration. The control circuitry may be configured to select the first subset or the second subset based on the trigger condition. The control circuitry may be configured to select one of the heating profiles from the respective first or second subset based on the detected type of aerosol-forming substrate.

The aerosol-generating device may comprise a substrate detector configured to detect the type of aerosol-forming substrate used with the device. The substrate detector may be configured to detect a property of an aerosol-forming substrate used with the device or a property of an aerosol-generating article comprising the aerosol-forming substrate. The property may be a physical or chemical property of the aerosol-forming substrate. The substrate detector may comprise an emitter of electromagnetic radiation and a receiver of electromagnetic radiation and the property may be a spectroscopic property related to the aerosol-forming substrate or aerosolgenerating article. The property may relate to a taggant or other indicia incorporated into the aerosol-forming substrate or aerosol-generating article.

The control circuitry may be configured to determine the type of aerosol-forming substrate used with the device based on signals received from the substrate detector. The control circuitry may be configured to determine the type of aerosol-forming substrate used with the device during the usage session or prior to the usage session. If the control circuitry is configured to determine the type of aerosol-forming substrate used with the device during the usage session, it may be configured to do so during the first period.

In a second aspect, there is provided an aerosol-generating system. The aerosolgenerating system may comprise an aerosol-generating device. The aerosol-generating device may be an aerosol-generating device according to the first aspect.

The aerosol-generating system may further comprise one or more aerosol-generating articles. The or each of the one or more aerosol-generating articles may comprise a rod of aerosol-forming substrate.

As described in relation to the first aspect, the control circuitry of the aerosol-generating device may advantageously select a predetermined heating profile having the first or second duration based on a trigger condition. In one example, the control circuitry may make this selection independently of the type of aerosol-forming substrate used with the device. In another example, the control circuitry may be configured to use a detected type of aerosol-forming substrate in addition to the determined puff behaviour to select a particular predetermined heating profile from a subset of predetermined heating profiles having the first or second duration.

The aerosol-generating system may comprise a plurality of aerosol-generating articles. At least two of the aerosol-generating articles may comprise a rod of the first type of aerosol-forming substrate.

A first aerosol-generating article of the plurality of aerosol-generating articles may comprise a first identifier. A second aerosol-generating article of the plurality of aerosolgenerating articles may comprise a second identifier that is different to the first identifier. The first and second aerosol-generating articles may comprise a rod of the first type of aerosol-forming substrate. Preferably, other than the for the first and second identifier, the first and second aerosolgenerating articles may comprise substantially the same structure as one another.

The first and second identifier may each comprise a taggant, bar code or other printed indicia. Preferably, the first identifier comprises a first taggant and the second identifier may comprise a second taggant.

The provision of a taggant on the aerosol-generating article may allow the aerosolgenerating article to be detected and identified by an aerosol-generating device which includes a suitable detector. For example, the taggant may comprise a photoluminescent material having an emission half-life of between 50 microseconds and 1000 microseconds after photoexcitation of the photoluminescent material.

As used herein with reference to the present invention, the term “emission half-life” refers to the time taken for an intensity of radiation emission by the photoluminescent material to decay by half after the photoluminescent material has been irradiated by a source of radiation and after the source of radiation has been removed or switched off.

An aerosol-generating article may comprise an aerosol-forming substrate, a downstream section provided downstream of the aerosol-forming substrate, and a taggant provided on the downstream section, wherein an upstream end of the taggant is at least 0.5 millimetres from the downstream end of the aerosol-generating substrate.

Providing the taggant at a positon 0.5 millimetres downstream of the aerosolgenerating substrate affords several advantages. Firstly, the provision allows the detector to be located away and downstream of the portion of the cavity which is heated by one or more electrical heater elements. During repeated use, the portion of the cavity which becomes heated may develop a build-up of heating by-products and slurry which may condense on the inside wall of the cavity. Positioning the taggant at least 0.5 millimetres away from the aerosol-generating substrate may also allow the detector to be located at least 0.5 millimetres away from the portion of the cavity which is most susceptible to the build-up of heating by-products and slurry. This may advantageously improve the reliability of the detector.

Secondly, the provision prevents the taggant itself from being directly heated during use since the taggant is located at a position downstream of the location of the aerosolgenerating article which needs to be heated. It is anticipated that some taggants may degrade or become damaged if they are heated. Locating the taggant downstream of the aerosol-generating substrate may therefore advantageously improve the reliability of the taggant detection since it may prevent the taggant from becoming damaged. In addition, this provision may prevent the taggant from coming into contact with heating by-products and slurry which is most likely to be located in the portion of the cavity which is heated during use. This may therefore further improve the reliability of the taggant detection by preventing contamination of the taggant.

Thirdly, the provision allows the taggant to be located very close to the opening of the cavity when the aerosol-generating article is fully inserted in the cavity. This may allow the detector to be located close to the opening of the cavity. This may allow the detector to be readily cleaned using a suitable tool where heating by-products and slurry does become deposited on the detector. This may advantageously improve the reliability of the detector.

The upstream end of the taggant may be at least 0.5 millimetres from the downstream end of the aerosol-generating substrate. For example, the upstream end of the taggant may be at least 1 millimetre, at least 1 .5 millimetres, or at least 2 millimetres from the downstream end of the aerosol-generating substrate.

The taggant may be provided on any component on the downstream section. For example, the taggant may be provided on one or more of an adhesive, a wrapper, a tipping paper, a filter plug, a susceptor, a mouthpiece filter, a space tube, or a flavourant where present. The taggant may be provided on more than one component. This may advantageously make detection of the taggant by the detector more reliable.

The downstream section may comprise a wrapper. The wrapper may circumscribe one or more components of the downstream section. The wrapper may join the downstream section to the aerosol-generating substrate. The downstream section may comprise more than one wrapper. For example, the downstream section may comprise a tipping paper or a combining wrapper. Where the downstream section comprises more than one wrapper, and the wrappers overlap, the taggant may be provided on the outermost wrapper. The outermost wrapper may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in specific embodiments of the invention are known in the art and include, but are not limited to: cigarette papers; and filter plug wraps.

The taggant may be provided on the inner surface of the wrapper. This may advantageously further protect the taggant from becoming damaged or contaminated. This may advantageously improve the reliability of the taggant.

The taggant may be provided on the inner surface of the outermost wrapper.

The taggant may be provided on the outer surface of the wrapper. The taggant may be provided on both the inner and outer surface of the wrapper.

The taggant may be printed on the inner surface of the wrapper. The taggant may be sprayed, or painted on the inner surface of the wrapper.

The length of the rod of aerosol-forming substrate may be at least 30 percent of the length of the aerosol-generating article. The rod of aerosol-forming substrate may have a tobacco content of between 30 percent by weight on dry weight basis and 90 percent by weight on a dry weight basis.

The aerosol-generating article may comprise a hollow tubular element at a downstream end of the rod of aerosol-forming substrate. The aerosol-generating article may comprise a mouthpiece element at a downstream end of the hollow tubular element.

In some aerosol-generating articles it may be desirable to include components other than tobacco and aerosol former in the rod of aerosol-forming substrate. For example, it may be desirable to include one or more flavourants in the rod of aerosol-forming substrate.

The term “flavourant” refers to organoleptic compounds, compositions, or materials that alter and are intended to alter the taste or aroma characteristics of one or more components of the aerosol-forming substrate during consumption or inhalation thereof. The flavourant may, for example, alter and or be intended to alter the taste or aroma characteristics of nicotine during consumption or inhalation thereof. For the purpose of this disclosure, nicotine is not considered as a “flavourant” or flavour.

The rod of aerosol-forming substrate may comprise one of more flavourants. The rod of aerosol-forming substrate may comprise a plurality of flavourants.

The rod of aerosol-forming substrate may have a flavourant content of at least 0.1 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 1 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 3 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 5 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 8 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 10 percent by weight on a dry weight basis. The rod of aerosolforming substrate may have a flavourant content of at least 13 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 15 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of at least 18 percent by weight on a dry weight basis.

The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 25 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 20 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 18 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 15 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 13 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 10 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 8 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of less than or equal to 5 percent by weight on a dry weight basis.

The rod of aerosol-forming substrate may have a flavourant content of between 0.1 and 25 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of between 0.1 and 20 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of between 5 and 20 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of between 10 and 20 percent by weight on a dry weight basis. The rod of aerosol-forming substrate may have a flavourant content of between 15 and 20 percent by weight on a dry weight basis.

The one or more flavourants may be one or more of: clove, ginger, mint, rosemary, star anise, and tea. The plurality of flavourants may be a combination of two or more of: clove, ginger, mint, rosemary, star anise, and tea.

In one example, the rod of aerosol-forming substrate may comprise clove.

The rod of aerosol-forming substrate may comprise at least 30 milligrams of flavourant. The rod of aerosol-forming substrate may comprise at least 35 milligrams of flavourant. The rod of aerosol-forming substrate may comprise at least 40 milligrams of flavourant. The rod of aerosol-forming substrate may comprise at least 45 milligrams of flavourant. The rod of aerosolforming substrate may comprise at least 50 milligrams of flavourant.

The hollow tubular element may have a length of at least 15 millimetres. The hollow tubular element may have a length of at least 17 millimetres. The hollow tubular element may have a length of at least 19 millimetres.

The hollow tubular element may have a length of less than or equal to 30 millimetres. The hollow tubular element may have a length of less than or equal to 25 millimetres. The hollow tubular element may have a length of less than or equal to 23 millimetres.

The hollow tubular element may have a length of between 15 millimetres and 30 millimetres. The hollow tubular element may have a length of between 17 millimetres and 25 millimetres. The hollow tubular element may have a length of between 19 millimetres and 23 millimetres. In one example, the length of the hollow tubular element is 12 millimetres.

In a third aspect there is provided a method of controlling power supply to a heater assembly of an aerosol-generating device for generating an aerosol from an aerosol-generating article comprising an aerosol-forming substrate during a usage session. The usage session may comprise a usage session start, The usage session may comprise a usage session end.

The method may comprise detecting a trigger condition. The trigger condition may be dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device.

The method may comprise selecting one of a plurality of predetermined heating profiles for use during the usage session. The selection may be based on the detected trigger condition. At least one of the plurality of predetermined heating profiles may have a first duration. At least one of the plurality of predetermined heating profiles may have a second duration. The second duration may be different to the first duration. The selected predetermined heating profile may have either the first duration or the second duration.

The method may comprise controlling the supply of power to the heater assembly according to the selected predetermined heating profile having either the first duration or the second duration.

The method may comprise detecting at least one of a user interaction with the aerosolgenerating device, or a property of an aerosol-generating article used with the device.

The aerosol-generating device may comprise a device housing defining a cavity for receiving the aerosol-generating article. The cavity may be configured to receive at least a portion of the aerosol-generating article comprising the aerosol-forming substrate. The method may comprise detecting a property of aerosol-generating article received in the cavity, preferably an identifier of the aerosol-generating article.

The method may comprise selecting a predetermined heating profile having either the first duration or the second duration dependent on whether the first or second identifier is detected. The method may comprise selecting a predetermined heating profile having the first duration when the first identifier is detected. The method may comprise selecting a predetermined heating profile having the second duration when the second identifier is detected.

The method may comprise determining a user puff behaviour during a first period of the usage session.

The method may comprise selecting a predetermined heating profile having either the first duration or the second duration dependent on the determined user puff behaviour.

The method may comprise controlling the supply of power to the heater assembly according to the selected predetermined heating profile during a second period of the usage session.

The method may comprise determining the user puff behaviour based on one or more user puffs of the first period of the usage session. The method may comprise determining user puff behaviour over a plurality of user puffs during the first period.

The method may comprise determining a mean average puff behaviour for a plurality of user puffs during the first period.

The method may monitor the number of puffs that have occurred during the first period. The first period end may be when the control circuitry has detected that a predetermined number of puffs have occurred during the first period.

The method may comprise detecting a user puff behaviour based on signals received from a detector of the aerosol-generating device. Features described in relation to one aspect may be applied to other aspects of the disclosure. In particular advantageous or optional features described in relation to the first aspect of the disclosure may be applied to the second or third of the disclosure, and vice versa.

The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

EX1. An aerosol-generating device for generating an aerosol from an aerosolgenerating article comprising an aerosol-forming substrate, the aerosol-generating device being configured to generate the aerosol during a usage session comprising a usage session start and a usage session end, the aerosol-generating device comprising: a heater assembly for heating the aerosol-forming substrate; a power supply configured to supply power to the heater assembly; and control circuitry comprising a memory in which a plurality of predetermined heating profiles are stored, at least one of the plurality of predetermined heating profiles having a first duration and at least one of the predetermined heating profiles having a second duration different to the first duration; wherein the control circuitry is configured to detect a trigger condition and select a predetermined heating profile for use during the usage session based on the detected trigger condition, in which the selected predetermined heating profile has either the first duration or the second duration, and in which the trigger condition is dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device.

EX2. An aerosol-generating device according to example EX1 , wherein the control circuitry is configured to control the supply of power to the heater assembly according to the selected predetermined heating profile having either the first duration or the second duration.

EX3. An aerosol-generating device according to example EX1 or EX2, wherein both the first duration and the second duration are longer than 1 minute, preferably, longer 2 minutes.

EX4. An aerosol-generating device according to any one of the preceding examples, wherein the first duration is longer than the second duration.

EX5. An aerosol-generating device according to any one of the preceding examples, wherein the first duration is at least 30% longer than the second duration, preferably at least 40% longer, preferably at least 50% longer, preferably at least 75% longer.

EX6. An aerosol-generating device according to any one of the preceding examples, wherein the first duration is no more than 18 minutes, preferably no more than 15 minutes, preferably no more than 12 minutes.

EX7. An aerosol-generating device according to any one of the preceding examples, wherein the first duration is longer than 5 minutes, preferably longer than 6 minutes, preferably longer than 8 minutes. EX8. An aerosol-generating device according to any one of the preceding examples, wherein the second duration is no more than 8 minutes, preferably no more than 6 minutes, preferably no more 4 minutes.

EX9. An aerosol-generating device according to any one of the preceding examples, wherein the second duration is longer than 1 minute, preferably longer than 2 minutes.

EX10. An aerosol-generating device according to any one of the preceding examples, wherein the duration of the usage session is dependent on the duration of the selected predetermined heating profile.

EX11 . An aerosol-generating device according to any one of the preceding examples, wherein the maximum duration of the usage session is at least 5 minutes, preferably at least 6 minutes, preferably at least 8 minutes, preferably at least 10 minutes, preferably at least 12 minutes if the selected predetermined heating profile has the first duration.

EX12. An aerosol-generating device according to any one of the preceding examples, wherein the maximum duration of the usage session is no more than 10 minutes, preferably no more than 8 minutes, preferably no more than 7 minutes, preferably no more than 6 minutes if the selected predetermined heating profile has the second duration.

EX13. An aerosol-generating system according to any one of the preceding examples, wherein the plurality of predetermined heating profiles comprise a first predetermined heating profile having the first duration and a second predetermined heating profile having the second duration.

EX14. An aerosol-generating device according to any one of the preceding examples, wherein the usage session comprises a plurality of puffs.

EX15. An aerosol-generating device according to example EX14, wherein the usage session comprises at least 6 puffs, preferably at least 8 puffs, preferably at least 10 puffs, preferably at least 12 puffs.

EX16. An aerosol-generating device according to an one of the preceding examples, wherein the usage session end corresponds to the end of the selected predetermined heating profile.

EX17. An aerosol-generating device according to any one of the preceding examples, further comprising a detection assembly configured to detect at least one of a user interaction with the aerosol-generating device, or a property of an aerosol-generating article used with the device.

EX18. An aerosol-generating device according to example EX17, wherein the aerosolgenerating device comprises a device housing defining a cavity for receiving the aerosol-forming substrate.

EX19. An aerosol-generating device according to example EX18, wherein the detection assembly is configured to detect a property of aerosol-generating article received in the cavity. EX20. An aerosol-generating device according to example EX19, wherein the detection assembly is configured to detect an identifier of the aerosol-generating article received in the cavity.

EX21 . An aerosol-generating device according to example EX20, wherein the detector assembly is configured to distinguish between a first identifier and a second identifier that is different to the first identifier.

EX22. An aerosol-generating device according to example EX21 , wherein the control circuitry is configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether the first or second of identifier is detected.

EX23. An aerosol-generating device according to example EX21 or EX22, wherein the control circuitry is configured to select a predetermined heating profile having the first duration when the first identifier is detected.

EX24. An aerosol-generating device according to any one of examples EX21 to EX23, wherein the control circuitry is configured to select a predetermined heating profile having the second duration when the second identifier is detected.

EX25. An aerosol-generating device according to any one of the preceding examples, wherein the control circuitry is configured to determine a user puff behaviour during a first period of the usage session.

EX26. An aerosol-generating device according to example EX25, wherein the control circuitry is configured to select a predetermined heating profile having either the first duration or the second duration dependent on the determined user puff behaviour.

EX27. An aerosol-generating device according to example EX26, wherein the control circuitry is configured to control the supply of power to the heater assembly according to the selected predetermined heating profile during a second period of the usage session.

EX28. An aerosol-generating device according to example EX26 or EX27, wherein the first period of the usage session comprises one or more user puffs.

EX29. An aerosol-generating device according to example EX28, wherein the first period of the usage session comprises a plurality of user puffs.

EX30. An aerosol-generating device according to any one of examples EX26 to EX29, wherein the control circuitry is configured to determine the user puff behaviour based on one or more user puffs of the first period of the usage session.

EX31 . An aerosol-generating device according to example EX30, wherein the control circuitry is configured to assess the determined user puff behaviour over a plurality of user puffs during the first period.

EX32. An aerosol-generating device according to example EX31 , wherein the control circuitry is configured to determine a mean average puff behaviour for a plurality of user puffs during the first period. EX33. An aerosol-generating device according to any one of examples EX26 to EX32, wherein the first period comprises a first period start and a first period end.

EX34. An aerosol-generating device according to example EX33, wherein the first period end is at least 20 seconds after the first period start, preferably at least 30 seconds after the first period start, preferably at least 40 seconds after the first period start, preferably at least 50 seconds after the first period start, preferably at least 75 seconds after the first period start, preferably at least 90 seconds after the first period start.

EX35. An aerosol-generating device according to example EX33 or EX34, wherein the first period start is no more than 150 seconds, preferably no more than 140 seconds, preferably no more than 130 seconds, preferably no more than 120 seconds, preferably no more than 110 seconds from the first period start.

EX36. An aerosol-generating device according to any one of examples EX33 to EX35, wherein the first period end is a predetermined time after the first period start.

EX37. An aerosol-generating device according to example EX36, wherein the predetermined time is at least 20 seconds, preferably at least 30 seconds, preferably at least 40, preferably at least 50 seconds, preferably at least 75 seconds, preferably at least 90 seconds.

EX38. An aerosol-generating device according to example EX36 or EX37, wherein the predetermined time is not more than 150 seconds, preferably not more than 140 seconds, preferably not more than 130 seconds, preferably not more than 120 seconds, preferably not more than 110 seconds.

EX39. An aerosol-generating device according to any one of examples EX26 to EX38, wherein the control circuitry is configured to monitor the number of puffs that have occurred during the first period.

EX40. An aerosol-generating device according to example EX39, wherein the control circuitry is configured such that the first period end is when the control circuitry has detected that a predetermined number of puffs have occurred during the first period.

EX41 . An aerosol-generating device according to example EX40, wherein the predetermined number of user puffs during the first period may be at least 2 puffs, preferably at least 3 puffs.

EX42. An aerosol-generating device according to any one of examples EX33 to EX41 , wherein the first period start corresponds to the usage session start.

EX43. An aerosol-generating device according to example EX42, wherein the first period of the usage session is an initial period of the usage session.

EX44. An aerosol-generating device according to any one of examples EX25 to EX43, further comprising a detection assembly configured to detect a user interaction with the aerosolgenerating device, the user interaction comprising a user puff. EX45. An aerosol-generating device according to example EX44, wherein the control circuitry is configured to determine the user puff behaviour during the first period of the usage session based on signals received from the detection assembly.

EX46. An aerosol-generating device according to example EX44 or EX45, wherein the detection assembly is configured to detect a parameter indicative of a user puff.

EX47. An aerosol-generating device according to example EX46, wherein the control circuitry is configured to detect a user puff based on changes in the detected parameter.

EX48. An aerosol-generating device according to any one of examples 24 to 30, wherein the detection assembly comprises a pressure sensor, a flow sensor, a temperature sensor or an aerosol quantity sensor.

EX49. An aerosol-generating device according to any one of the preceding examples, further comprising one or more user interface elements.

EX50. An aerosol-generating device according to example EX49, further comprising a detection assembly configured to detect a user interaction with the aerosol-generating device, the detection assembly comprising the user interface element.

EX51 . An aerosol-generating device according to example EX50, wherein the user interaction comprises user manipulation of at least one of the one or more user interface elements.

EX52. An aerosol-generating device according to example EX50 or EX51 , wherein the one or more user interface elements are configured such that a first state and a second state are selectable using the one or more user interface elements by a user of the device.

EX53. An aerosol-generating device according to example EX52, wherein the control circuitry is configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether the first state or second state of the user interface is selected.

EX54. An aerosol-generating device according to example EX52 or EX53, wherein the first state corresponds to a predetermined heating profile having the first duration and the second state correspond to a predetermined heating profile having the second duration.

EX55. An aerosol-generating device according to any one of examples EX52 to EX53, wherein the control circuitry is configured to select a predetermined heating profile having the first duration when the first state is selected by the user interface element.

EX56. An aerosol-generating device according to any one of examples EX52 to EX55, wherein the control circuitry is configured to select a predetermined heating profile having the second duration when the select state is selected by the user interface element.

EX57. An aerosol-generating device according to any one of the preceding examples, wherein the aerosol-generating device is configured for generating aerosol from an aerosolforming substrate comprised in the aerosol-generating article. EX58. An aerosol-generating device according to any one of the preceding examples, wherein the aerosol-generating article comprises a wrapper circumscribing the aerosol-forming substrate.

EX59. An aerosol-generating device according to any one of the preceding examples, wherein the aerosol-forming substrate is a solid aerosol-forming substrate.

EX60. An aerosol-generating device according to any one of the preceding examples, wherein the aerosol-generating device comprises a device housing defining a cavity for receiving the aerosol-forming substrate.

EX61 . An aerosol-generating system comprising the aerosol-generating device of any one of the preceding examples and one or more aerosol-generating articles comprising a rod of aerosol-forming substrate.

EX62. An aerosol-generating system according to example EX61 , comprising a plurality of aerosol-generating article comprising a rod of a first type of aerosol-forming substrate.

EX63. An aerosol-generating system according to example EX61 or EX62, wherein a first aerosol-generating article of the plurality of aerosol-generating articles comprises a first identifier and wherein a second aerosol-generating article of the plurality of aerosol-generating articles comprises a second identifier that is different to the first identifier.

EX64. An aerosol-generating system according to example EX63, wherein, other than the for the first and second identifier, the first and second aerosol-generating articles comprise the substantially the same structure as one another.

EX65. An aerosol-generating system according to example EX63 or EX64, wherein the first and second identifier each comprise a taggant.

EX66. An aerosol-generating system according to any one of examples EX63 to EX65, wherein the rod of aerosol-forming substrate comprises one of more flavourants.

EX67. An aerosol-generating system according to example EX66, wherein the rod of aerosol-forming substrate comprises a plurality of flavourants.

EX68. An aerosol-generating system according to example EX67 or EX68, wherein the one or more flavourants is one or more of: clove, ginger, mint, rosemary, star anise, and tea.

EX69. An aerosol-generating system according to example EX68, wherein the rod of aerosol-forming substrate comprises clove.

EX70. A method of controlling power supplied to a heater assembly of an aerosolgenerating device for generating an aerosol from an aerosol-generating article comprising an aerosol-forming substrate during a usage session comprising a usage session start and a usage session end, the method comprising: detecting a trigger condition in which the trigger condition is dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device; selecting one of a plurality of predetermined heating profiles for use during the usage session based on the detected trigger condition, at least one of the plurality of predetermined heating profiles having a first duration and at least one of the predetermined heating profiles having a second duration different to the first duration, wherein the selected predetermined heating profile has either the first duration or the second duration.

Examples will now be further described with reference to the figures in which:

Figure 1 is a schematic illustration of a cross-section of a first embodiment of an aerosolgenerating system comprising an aerosol-generating device according to the present disclosure and aerosol-generating article;

Figure 2 is a schematic illustration of a cross-section of the aerosol-generating article of Figure 1 shown separately from the aerosol-generating device;

Figure 3 is a graph representing first and second predetermined heating profiles stored in the memory of control circuitry of the aerosol-generating device of Figure 1 ;

Figure 4 is a flow chart representing a method of controlling power supplied to a heater assembly of the aerosol-generating device of Figure 1 during a usage session;

Figure 5 is a graph of the temperature of a heater element of the heater assembly of the aerosol-generating device during a usage session in which a user follows a first user puff behaviour;

Figure 6 is a graph of the temperature of a heater element of the heater assembly of the aerosol-generating device during a usage session in which a user follows a second user puff behaviour;

Figure 7 is a schematic illustration of a cross-section of a second embodiment of an aerosol-generating system comprising a second aerosol-generating device and an aerosolgenerating article;

Figure 8 is a flow chart representing a method of controlling power supplied to a heater assembly of the aerosol-generating device of Figure 7;

Figure 9 is a schematic illustration of a cross-section of an aerosol-generating article for use with a third aerosol-generating device;

Figure 10 is a schematic illustration of a cross-section of a third aerosol-generating device for use with the aerosol-generating article shown in Figure 9; and

Figure 11 is a flow chart representing a method of controlling power supplied to a heater assembly of the aerosol-generating device of Figure 10.

Figure 1 is a schematic of a cross sectional view of a first aerosol-generating device 100. The aerosol-generating device 100 comprises a cavity 10 defined by a device housing 11 . The cavity 10 is tubular and has at an upstream end a base 12. The cavity 10 is configured for receiving an aerosol-generating article 200. An aerosol-generating article 200 is received in the cavity 10. The aerosol-generating article 200 is shown separately from the aerosol-generating device 100 in Figure 2. Figure 2 is also a schematic of a cross sectional view of the aerosol-generating article 200.

The aerosol-generating article 200 comprises a rod of aerosol-forming substrate 212 and a downstream section 214 at a location downstream of the rod of aerosol-forming substrate 212. The downstream section 214 comprises a hollow tubular element 220 and a mouthpiece element 204.

The aerosol-generating article 200 comprises an upstream wrapper 244 circumscribing the aerosol-forming substrate 212 and the hollow tubular element 220.

The aerosol-generating article 200 also comprises a tipping wrapper 252 circumscribing the hollow tubular element 220 and the mouthpiece element 204. The tipping wrapper 252 overlies the portion of the upstream wrapper 244 that overlies the hollow tubular element 220. In this way, the tipping wrapper 252 effectively joins the mouthpiece element 204 to the rest of the components of the aerosol-generating article 200. In this example, the width of the tipper wrapper 252 is about 26 millimetres.

The aerosol-generating article 200 has an overall length of about 45 millimetres and an outer diameter of about 7.2 mm.

The rod of aerosol-forming substrate 212 comprises a shredded tobacco material. In this example, the rod of aerosol-forming substrate 212 also comprises clove. The rod of aerosolforming substrate 212 comprises 150 milligrams of a shredded tobacco material comprising from 13 percent by weight to 16 percent by weight of glycerine. The density of the aerosol-forming substrate is about 300 mg per cubic centimetre. The RTD of the rod of aerosol-forming substrate 212 is between about 6 to 8 mm H2O. The rod of aerosol-forming substrate 212 also includes 52 milligrams of clove. The rod of aerosol-forming substrate 212 is individually wrapped by a plug wrap (not shown).

The hollow tubular element 220 is located immediately downstream of the rod 212 of aerosol-forming substrate. The hollow tubular element 220 is in longitudinal alignment with the rod 212 of aerosol-forming substrate. The upstream end of the hollow tubular element 220 abuts the downstream end of the rod 212 of aerosol-forming substrate.

The hollow tubular element 220 defines a hollow section of the aerosol-generating article 10. The hollow tubular element does not substantially contribute to the overall RTD of the aerosolgenerating article. In more detail, an RTD of the hollow tubular element 220 is about 0 mm H2O.

The hollow tubular element 220 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular element 220 defines an internal cavity 222 that extends all the way from an upstream end of the hollow tubular element 20 to a downstream end of the hollow tubular element 220. The internal cavity 222 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 22. The hollow tubular element 220 does not substantially contribute to the overall RTD of the aerosol-generating article 200. In this example, the hollow tubular element 220 has a length of about 21 millimetres, an external diameter of about 7.2 millimetres, and an internal diameter of about 6.7 millimetres. Thus, a thickness of a peripheral wall of the hollow tubular element 20 is about 0.25 millimetres.

The aerosol-generating article 200 comprises a ventilation zone 230 provided at a location along the hollow tubular element 20.

The ventilation zone 230 may also comprise a circumferential row of perforations provided on the upstream wrapper 244. The perforations of the upstream wrapper 244 overlap the perforations provided on the hollow tubular element 220. Accordingly, the upstream wrapper 244 overlies the perforations of the ventilation zone 230 provided on the hollow tubular element 220.

The mouthpiece element 204 extends from the downstream end of the hollow tubular element 220 to the downstream or mouth end of the aerosol-generating article 200. The mouthpiece element 204 has a length of about 7 mm. An external diameter of the mouthpiece element 204 is about 7.2 mm. The mouthpiece element 204 comprises a low-density, cellulose acetate filter segment. The RTD of the mouthpiece element 204 is about 8 mm H2O. The mouthpiece element 204 may be individually wrapped by a plug wrap (not shown).

An aerosol-generating device 100 together with an aerosol-generating article 200, as shown in Figure 1 , may be referred to as an aerosol-generating system.

The aerosol-generating device 100 of the aerosol-generating system comprises a heater assembly comprising a heating element 110. The heating element 110 surrounds the cavity 10 along a portion of the cavity in which the aerosol-forming substrate of the aerosol-generating article 200 is received. In an alternative embodiment, the heating element 110 forms a portion of the housing 11 that defines the part of the cavity that receives the aerosol-forming substrate. The heating element 110 is a resistive heating element.

An airflow channel 120 extends from an air inlet 122 of the aerosol-generating device 100. Upstream of the cavity, the airflow channel 120 is primarily defined by an airflow channel wall 124. Downstream of the airflow channel wall 124, the airflow channel 120 passes through an air outlet defined in the base 12 of the cavity. The airflow channel 120 then extends through the cavity 10. When an aerosol-generating article 200 is received in the cavity 10, the airflow channel 120 passes through the aerosol-generating article 200 and extends through a mouthpiece 204.

The aerosol-generating device 100 further comprises a power supply 130 in form of a rechargeable battery for powering the heating element 110 controllable by control circuitry 132. The power supply is connected to the control circuitry 132 and the heating element 110 via electrical wires and connections that are not shown in the Figures. The aerosol-generating device may comprise further elements, not shown in the Figures, such as a button for activating the aerosol-generating device.

A usage session of the aerosol-generating device 100 is initiated following a user of the aerosol-generating device turning the device on, for example using the button or switch on the aerosol-generating device. The usage session comprises a usage session start which corresponds to the point at which the aerosol-generating device 100 is initiated, and a usage session end which corresponds to the point at which the aerosol-generating device 100 is switched off.

Initiation of the aerosol-generating device 100 at the usage session start causes the control circuitry 132 to supply electrical power from the power supply 130 to the heating element 110 such that an electrical current passes through the heating element 110 causing the heating element 110 to heat up. Heat is transferred to the aerosol-forming substrate such that volatile compounds are vaporised from the aerosol-forming substrate.

During a usage session, a user will puff on the mouthpiece 204 of the received aerosolgenerating article 200 a plurality of times. During each user puff, inhalation on the mouthpiece 204 of the received aerosol-generating article 200 results in air being drawn through the airflow channel 120 towards the user’s mouth. During a puff, air will be drawn from outside of the aerosolgenerating device into the airflow channel 120 through air inlet 122, through the air inlet defined in the base 12 of the cavity 10 and into the cavity. Because the aerosol-generating article 200 is received in the cavity 10, the air drawn into the cavity 10 will enter the aerosol-generating article 200 at its distal end 216. Thus, the air passes through the aerosol-forming substrate 212. In doing so, volatile compounds generated by the heating of the substrate 212 will become entrained in the air. As the air continues towards the mouth end of the aerosol-generating article 200, the volatile compounds cool to form an aerosol which is then inhaled by a user of the device.

As described in more detail below, the control circuitry 132 is configured to control the supply of power to the heater assembly according to one or more of the predetermined heating profiles throughout the usage session. The control circuitry 132 comprises a memory in which a plurality of predetermined heating profiles that are different to one another are stored. The predetermined heating profiles are effectively instructions for the control circuitry to control the supply of power to the heater assembly such that heating element is heated with reference to a plurality of target temperatures. Each predetermined heating profile comprises information relating to values for the target temperatures, the order of the target temperatures and the length of time that the control circuitry is configured to supply power to the heater assembly with respect to each individual target temperature. Each predetermined heating profile is configured to ensure consistent aerosol generation throughout a usage session assuming a particular user puff behaviour.

A first predetermined heating profile and a second predetermined heating profile are stored in the memory of the control circuitry 132 and the control circuitry 132 is configured to select one of the first and second predetermined heating profiles based on a trigger condition.

In a first example, the trigger condition is dependent on a user puff behaviour. In particular, a user puff behaviour during an initial portion of the usage session is determined and the determined user puff behaviour is used to select the first or second predetermined heating profile. This is described in more detail in relation to Figures 3 to 6.

Figure 3 is a graph 300 representing first and second predetermined heating profiles stored in the memory of the control circuitry 132. Graph 300 is schematic and is not drawn to scale.

Graph 300 comprises time on the x axis 302 and temperature on the y axis 304 and shows a full usage session with the usage session start being at t=0 seconds. The usage session is split into a first period 306 and a second period 308a, 308b. As well be explained, the second period 308a is associated with the first predetermined heating profile and the second period 308b is associated with the second predetermined heating profile.

The first period comprises a first period start at t=0 seconds and further comprises a first period end which corresponds to a second period start such that the first and second period are sequential.

The first predetermined heating profile is represented by 310 on graph 300 and the second predetermined heating profile is represented by 312. Each of the first and second predetermined heating profiles comprise four target temperatures. The target temperature is changed in a step-wise manner as the usage session progresses. The first predetermined heating profile 310 has a longer overall duration than the second predetermined heating profile 312.

An initial target temperature for each of the first and second predetermined heating profiles throughout the first period 306 is the same such that an initial portion of the first predetermined heating profile is identical to an initial portion of the second predetermined heating profile.

The initial target temperature for each of the first and second predetermined heating profiles is higher than subsequent target temperatures of the predetermined heating profiles. In this way, when either the first or second predetermined heating profile is selected, power is supplied to the heater assembly to rapidly increase the temperature of the heating element at the start of the usage session.

The first predetermined heating profile 310 is different to the second predetermined heating profile 312 after the first period 306. In particular, each of the second to fourth target temperatures of the first heating profile 310 are lower than the respective second to fourth target temperatures of the second heating profile 312. Furthermore, the first predetermined heating profile 310 comprises heating the heating element to each of the second to fourth target temperatures for longer than the respective second to fourth target temperature of the second heating profile 312.

The first predetermined heating profile 310 is suitable for a different user puff behaviour to the second predetermined heating profile 312. In particular, the longer and cooler first predetermined heating profile 310 is suitable for a user puff behaviour having a longer mean average puff interval and lower mean average puff frequency than a second user puff behaviour. The second period comprises a second period end which corresponds to the usage session end. Because the first predetermined heating profile is longer that the second predetermined heating profile, the second period is different depending on which predetermined heating profile is selected. In particular, the second period 308a on the graph 300 corresponds to the second period when the first predetermined heating profile is selected and the second period 308b corresponds to the second period when the second predetermined heating profile is selected.

Figure 4 is a flow diagram of a method of controlling power supplied to the heater assembly of the aerosol-generating device 100 during a usage session. Figure 5 is a graph 500 of the temperature of the heater element 110 during a usage session in which a user follows a first user puff behaviour and in which the method of Figure 4 is applied. Graph 500 is schematic and is not drawn to scale.

Like graph 300, graph 500 comprises time on the x axis 502 and temperature on the y axis 504 and shows a full usage session with the usage session start being at t=0 seconds. The usage session is again split into a first period 306 and a second period 308a.

Step 402 of the method of controlling power supplied to the heater assembly of the aerosol-generating device 100 during a usage session comprises supplying to the heater assembly during the first period 306 according to the initial portion of the first predetermined heating profile. As described in relation to Figure 3, the target temperature during the first period 306 is high and so the temperature of the heating element 100 rapidly increases to an operation temperature at the start of the first period 306 such that aerosol is generated for a user to inhale during a user puff.

The initial portion of the first and second predetermined heating profiles are identical. So, in an alternative example, step 302 of the method comprises controlling power supplied to the heater assembly during the first period 306 according to the initial portion of the second predetermined heating profile. The graph 500 would look identical during the first period 306 regardless of whether the first or second predetermined heating profile is followed initially.

Step 404 of the method comprises determining a user puff behaviour during the first period 306 of the usage session. Specifically, the user puff behaviour is the mean average of the interval between puffs during the first period.

The mean average interval between puffs is determined by detecting individual user puffs during the first period by detecting a temporary drop in the temperature of the heating element 110. The drop in the temperature of the heating element 110 is caused by the air drawn through the aerosol-generating device 100 during a user puff having a cooling effect on the heating element 110 in use. As such, puffs are indicated by the troughs 510 in Figure 5. The troughs 510 can be used to identify individual puffs.

The interval between subsequent individual puffs can be determined once the individual puffs have been identified by measuring the time between the start of the subsequent individual puffs. Because the first period is long enough for three or more puffs to occur, several puff intervals for subsequent puffs can be calculated throughout the first period. The mean average of those puff intervals can then be calculated. The mean average interval between subsequent puffs for the first period 306 is 36 seconds.

In this example, the control circuitry 132 is configured to perform step 402 and 404 of the method 400. The aerosol-generating device 100 comprises a temperature sensor (not shown) configured to measure the temperature of the heating element 110. The control circuitry 132 is configured to receive signals from the temperature sensor and detect a user puff based on changes (specifically, reductions) in the temperature of the heating element 1110. The control circuitry is then configured to calculate the mean average puff interval based on a determined interval between subsequent puffs.

In an alternative example, the heating element 110 comprises a material having an electrical resistance that is temperature dependent. For example, the heating element 110 is preferably made of a material which increases in resistance when the temperature resistance increases and where the relationship between resistance and temperature is substantially linear, at least in the operational temperature range of the heating element 110. In this example, the control circuitry 132 is configured to monitor the electrical resistance of the heating element 110. The electrical resistance can then be used to infer or calculate a temperature of the heating element 110. In particular, the control circuitry is configured to detect a user puff based on a drop in the resistance of the heating element 110 representative of a drop in the temperature of the heating element 110.

Step 406 of the method comprises using the determined user puff behaviour for the first period to select one of a plurality of predetermined heating profiles stored in the memory of the control circuitry 132 for the second period. In particular, step 406 of the method comprises comparing the determined mean average puff interval for the first period 306 determined in step 404 of the method with a predetermined threshold value. If the determined mean average puff interval is greater than the predetermined threshold value then the first predetermined heating profile is selected. If the determined mean average puff interval is less than or equal to the predetermined threshold value then the second predetermined heating profile is selected.

In this example, the predetermined threshold value is 25 seconds. The determined mean average puff interval for the first period 306 is 36 seconds (i.e. greater than the predetermined threshold value). So, the first predetermined heating profile is selected in step 406 of the method.

Step 408 of the method comprises controlling the supply of power to the heating assembly according to the selected predetermined heating profile until the end of second period. So, as the first predetermined heating profile was selected in step 406 in the example of Figure 5, the method comprises continuing to control the supply of power to the heating assembly according to the first predetermined heating profile in the second period. The graph 500 of Figure 5 shows the outcome of the method of Figure 4 when a user follows a first user puff behaviour. Figure 6 instead shows a graph 600 of the temperature of the heater element 110 during a usage session in which a user follows the second user puff behaviour and in which the method of Figure 4 is applied. Graph 600 is schematic and is not drawn to scale.

In this case, steps 402 and 404 of the method 400 are the same as described above. However, the puff interval in Figure 6 is shorter than in Figure 5. As such, the mean average puff interval determined at step 404 of the method is shorter when the user follows the second user puff behaviour than the first user puff behaviour. The mean average puff interval for the second user puff behaviour of Figure 6 in the first period is 20 seconds.

20 seconds is less than the predetermined threshold and so at step 406 of the method, the second predetermined heating profile is selected. Step 408 of the method comprises controlling the supply of power to the heating assembly according to the second predetermined heating profile during the second period. In particular, step 408 of the method comprises controlling the supply of power to the heating assembly according to a portion of the second predetermined heating profile following the initial portion. This is the portion that corresponds to the portion of second predetermined heating profile of the second period 308b in Figure 3.

Because the second predetermined heating profile is shorter than the first predetermined heating profile, the usage session in Figure 6 is shorter than the usage session of Figure 5. Similarly, a second period 308b of Figure 6 is shorter than a second period 308a of Figure 5.

In the example described above step 402 of the method comprises supplying to the heater assembly during the first period 306 according to the initial portion of the first (or second) predetermined heating profile. In an alternative example, a first, a second and a third predetermined heating profile are each stored in the memory of the control circuitry 132.

The third predetermined heating profile has a duration corresponding to the duration of the first period 306 and is identical to the initial portion of the first and second predetermined heating profiles described in relation to Figure 3.

The first and second predetermined heating profiles of this example do not include the initial portion and correspond to the portions of the first and second predetermined heating profiled described in relation to Figure 3 for the second period 308a, 308b respectively.

In this alternative example, step 402 of the method comprises supplying to the heater assembly during the first period 306 according to the third predetermined heating profile, step 406 comprises using a determined user puff behaviour for the first period to select one of the first and second predetermined heating profiles for the second period and step 408 comprises controlling the supply of power to the heating assembly according to the selected predetermined heating profile until the end of second period.

In the examples described above, the first period has a fixed duration of 100 seconds. Of course, other durations for the first period could be used but it is advantageous for the first period to last for several puffs. In some alternative examples, the first period is not fixed. Instead, the first period end is when the control circuitry has detected that a predetermined number of puffs have occurred since the first period start. In particular, the predetermined number of puffs is three puffs. The method of controlling power supplied to the heater assembly of the aerosol-generating device 100 during a usage session in this example is fundamentally the same as that described in relation to Figure 4. The only difference is that the first period has a dynamic, rather than fixed, length.

In a second example, the trigger condition is dependent on the output, state or user manipulation of one or more user interface elements of the aerosol-generating device. In particular, the user interface element is a rocker switch. This example is described in relation to Figures 7 and 8.

Figure 7 is a schematic of a cross sectional view of a second aerosol-generating device 700 comprising an aerosol-generating article 702 received in a cavity. The first aerosolgenerating device 700 and aerosol-generating article 702 are very similar to the aerosolgenerating device 100 and aerosol-generating article 200 shown in Figure 1 and like features are labelled accordingly. Compared to the first aerosol-generating device 100, the second aerosolgenerating device 700 comprises a switch 704 which is a rocker switch having a first position and a second position. Figure 7 shows the switch 704 in the first position.

Figure 8 is a flow diagram of a method of controlling power supplied to the heater assembly of the aerosol-generating device 700 during a usage session.

Step 802 of the method comprises detecting the state of the switch 702. In this example, the state of switch 702 is the trigger condition.

Step 804 of the method comprises using the detected state of the switch 702 to select one of the plurality of predetermined heating profiles for use during the usage session. If the switch is in the first position shown in Figure 7, then step 804 of the method comprises selecting the first predetermined heating profile, as shown in Figure 3. If the switch is in the second position, then step 804 of the method comprises selecting the second predetermined heating profile, as shown in Figure 3. So, if the second state is detected, the usage session will be shorter than if the first state is detected.

Step 806 of the method comprises controlling the supply of power to the heater assembly according to the selected predetermined heating profile.

In a third example, the trigger condition is dependent on a property of an aerosolgenerating article used with the device. In particular, the trigger condition depends on the detection of a taggant incorporated in the aerosol-generating article. This is described in relation to Figures 9, W and 11.

Figure 9 is a schematic illustration of a cross-section of an aerosol-generating article 900. The aerosol-generating article 900 is very similar to the aerosol-generating 200 shown in Figure 2 and like features are labelled accordingly. The difference between the aerosol-generating articles 200 and 900 is that the aerosol-generating article 900 additionally comprises a first taggant 902. The first taggant 902 is provided as a continuous band circumscribing the downstream section of the aerosol-generating article 10. The first taggant 902 is printed on the inner surface of the tipping wrapper 252. The upstream end of the first taggant 902 is located 2 millimetres downstream of the downstream end of the aerosol-generating substrate 212. The first taggant 902 has a length of 6.5 millimetres. The upstream end of the first taggant 902 is aligned with the upstream end of the tipping wrapper 252. The downstream end of the first taggant 902 is 3.5 millimetres upstream from the ventilation zone 30. Accordingly, the entire length of the first taggant 902 overlays the hollow tubular element 220. The first taggant 902 is provided in an concentration of about 200 milligrams per square metre. In this example, the first taggant 902 comprises a first photoluminescent material.

Figure 10 is a schematic illustration of a cross-section of a third aerosol-generating device 1000 for use with the aerosol-generating article 900. The third aerosol-generating device 1000 is similar to the first aerosol-generating device 100 shown in Figure 1 and like features are labelled accordingly. Compared to the first aerosol-generating device 100, the third aerosol-generating device 1000 comprises a taggant detector 1002. When the aerosol-generating article 1000 is fully inserted into the device cavity 10, the taggant 902 of the aerosol-generating article 1000 is aligned with the taggant detector 1002 of the aerosol-generating device 1000. The taggant detector 1002 is configured to detect the first taggant 902.

An aerosol-generating system (not shown in the Figures) comprises the aerosolgenerating device 1000 and a plurality of aerosol-generating articles 900. A first aerosolgenerating article 900 of the plurality of aerosol-generating articles comprises the first taggant 902 as shown in Figure 9. A second aerosol-generating article of the plurality of aerosolgenerating articles is identical to the first aerosol-generating article 900 shown in Figure 9 but comprises a second taggant that is different to the first taggant 902.

The taggant detector 1002 is capable of distinguishing between the first taggant and the second taggant.

Figure 11 is a flow diagram of a method of controlling power supplied to the heater assembly of the aerosol-generating device 1100 during a usage session.

Step 1102 of the method comprises a user inserting an aerosol-generating article 900 comprising either the first taggant or the second taggant into the cavity of the aerosol-generating device 900.

Step 1104 of the method comprises using the taggant detector 1002 to confirm the identity of the taggant of the aerosol-generating article 900 received in the cavity. In this example, the determined identity of the taggant of the aerosol-generating article 900 is the trigger condition.

Step 1106 of the method comprises using the determined identity of the taggant of the inserted aerosol-generating article 900 to select one of the plurality of predetermined heating profiles for use during the usage session. If the first taggant is identified in step 1104, then the first predetermined heating profile is selected. If the second taggant is identified in step 1104, then the second predetermined heating profile is selected.

Step 1108 of the method comprises controlling the supply of power to the heater assembly according to the selected predetermined heating profile.

The result of the above method is that the particular aerosol-generating article that is inserted into the cartridge of the aerosol-generating device can be used to choose a heating profile. A user of the aerosol-generating device can make a selection of the aerosol-generating article dependent on their preferred puffing behaviour. As the aerosol-generating articles are identical, the selection may not be dependent on the type of aerosol-forming substrate contained in the aerosol-generating article as the aerosol-forming substrate in each of the articles may be identical.

In the example above, two different taggants are used as a way of distinguishing aerosolgenerating articles. However, in other examples, the taggants may be replaced with other identifiers that are detectable and suitable for distinguishing between two or more aerosolgenerating articles. For example, a bar code may be printed on an outer surface of the aerosolgenerating article.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1 . An aerosol-generating device for generating an aerosol from an aerosol-generating article comprising an aerosol-forming substrate, the aerosol-generating device being configured to generate the aerosol during a usage session comprising a usage session start and a usage session end, the aerosol-generating device comprising: a heater assembly for heating the aerosol-forming substrate; a power supply configured to supply power to the heater assembly; and control circuitry comprising a memory in which a plurality of predetermined heating profiles are stored, at least one of the plurality of predetermined heating profiles having a first duration and at least one of the predetermined heating profiles having a second duration different to the first duration; wherein the control circuitry is configured to detect a trigger condition and select a predetermined heating profile for use during the usage session based on the detected trigger condition, in which the selected predetermined heating profile has either the first duration or the second duration, and in which the trigger condition is dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosol-generating article used with the device.

2. An aerosol-generating device according to claim 1 , wherein the first duration is at least 30% longer than the second duration.

3. An aerosol-generating device according to any one of the preceding claims, wherein the first duration is longer than 5 minutes, preferably longer than 8 minutes.

4. An aerosol-generating device according to any one of the preceding claims, further comprising a detection assembly configured to detect at least one of a user interaction with the aerosol-generating device, or a property of an aerosol-generating article used with the device.

5. An aerosol-generating device according to claim 4, wherein the detection assembly is configured to detect an identifier of the aerosol-generating article received in the cavity and is suitable for distinguishing between a first identifier and a second identifier that is different to the first identifier.

6. An aerosol-generating device according to claim 5, wherein the control circuitry is configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether a first or second of identifier is detected.

7. An aerosol-generating device according to any one of the preceding claims, wherein the control circuitry is configured to determine a user puff behaviour during a first period of the usage session, to select a predetermined heating profile having either the first duration or the second duration dependent on the determined user puff behaviour and to control the supply of power to the heater assembly according to the selected predetermined heating profile during a second period of the usage session.

8. An aerosol-generating device according to any one of the preceding claims, further comprising one or more user interface elements.

9. An aerosol-generating device according to claim 8, wherein the one or more user interface elements are configured such that a first state or a second state are selectable using the one or more user interface elements by a user of the device.

10. An aerosol-generating device according to claim 9, wherein the control circuitry is configured to select a predetermined heating profile having either the first duration or the second duration dependent on whether the first state or second state of the user interface is selected.

11. An aerosol-generating device according to any one of the preceding claims, wherein the aerosol-generating device is configured for generating aerosol from an aerosol-forming substrate comprised in the aerosol-generating article, wherein the aerosol-generating article comprises a wrapper circumscribing the aerosol-forming substrate.

12. An aerosol-generating system comprising the aerosol-generating device of any one of the preceding claims and one or more aerosol-generating articles comprising a rod of aerosolforming substrate.

13. An aerosol-generating system according to claim 12, wherein a first aerosol-generating article of the plurality of aerosol-generating articles comprises a first identifier and wherein a second aerosol-generating article of the plurality of aerosol-generating articles comprises a second identifier that is different to the first identifier.

14. An aerosol-generating system according to claim 13, wherein, other than the for the first and second identifier, the first and second aerosol-generating articles comprise the substantially the same structure as one another.

15. A method of controlling power supplied to a heater assembly of an aerosol-generating device for generating an aerosol from an aerosol-generating article comprising an aerosolforming substrate during a usage session comprising a usage session start and a usage session end, the method comprising: detecting a trigger condition in which the trigger condition is dependent on at least one of a user interaction with the aerosol-generating device or a property of an aerosolgenerating article used with the device; selecting one of a plurality of predetermined heating profiles for use during the usage session based on the detected trigger condition, at least one of the plurality of predetermined heating profiles having a first duration and at least one of the predetermined heating profiles having a second duration different to the first duration, wherein the selected predetermined heating profile has either the first duration or the second duration.