JP7817243B2 - Smoking device with a heating profile based on smoke volume - Google Patents

Description

The present disclosure relates to a method of operating an aerosol generating device, and to an aerosol generating device. Specifically, the present disclosure relates to an aerosol generating device and a method in which the temperature of a heating element is controlled with reference to user interaction.

Aerosol-generating devices configured to generate an aerosol from an aerosol-forming substrate, such as a tobacco-containing substrate, are known in the art. Typically, an inhalable aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-forming substrate or material, which may be located within, around, or downstream of the heat source. The aerosol-forming substrate may be a liquid substrate contained within a reservoir. The aerosol-forming substrate may be a solid substrate. The aerosol-forming substrate may be a component part of a separate aerosol-generating article configured to engage with the aerosol-generating device to form an aerosol. During consumption, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol, which is inhaled by the consumer.

Some aerosol generating devices are configured to provide a user experience of finite duration. The duration of a usage session may be limited, for example, to approximate the experience of consuming a traditional cigarette. Some aerosol generating devices are configured to be used with a separate consumable aerosol-generating article. Such aerosol-generating articles include aerosol-forming substrate(s) capable of emitting volatile compounds capable of forming an aerosol. The aerosol-forming substrate is typically heated to form an aerosol. As the volatile compounds in the aerosol-forming substrate are depleted, the quality of the aerosol generated may deteriorate. Therefore, some aerosol generating devices are configured to limit the duration of a usage session to help prevent the generation of lower-quality aerosol from a substantially depleted aerosol-forming substrate of the aerosol-generating article. A user inhales aerosol from such known aerosol generating devices by applying one or more puffs to the device during a usage session. Some known aerosol generating devices may limit the duration of a usage session based on when the number of puffs applied to the device during a session reaches a predetermined limit.

It is known to provide power to a heat source to heat an aerosol-forming substrate according to different thermal profiles over the duration of a use session. Indeed, these known thermal profiles define the temperature fluctuations of the heat source as a function of the time elapsed in the use session. As the aerosol-forming substrate becomes more depleted during a use session, more energy is required to extract the remaining volatile compounds from the substrate that form the aerosol. Therefore, it is known to use thermal profiles that increase the target operating temperature of the heat source over the second half of the use session. The known thermal profiles used to operate the heat source are based on an ideal, hypothetical use session. The ideal use session may be characterized by a predetermined length of the use session. The ideal use session may additionally be based on the user's assumed or ideal puff behavior, for example, assuming that consecutive puffs of a consistent, predetermined length are applied at a predetermined rate over a finite period of time. However, if the actual use session deviates from the assumptions inherent in the ideal use session, the use of these known thermal profiles to control the temperature of the heat source may lead to inefficient extraction of aerosol from the substrate, which may be detrimental to the overall user experience. As an example, if a user applies puffs at a rate faster than expected for a known heat profile, this may result in the use session terminating earlier than would be expected in an ideal use session. As a result, the temperature of the heat source may never reach the level required later in the use session to efficiently extract the aerosol from the substrate.

It is therefore desirable to overcome the deficiencies and limitations outlined above.

According to a first aspect of the present invention, there is provided a method of operating an aerosol generating device to generate an aerosol from an aerosol-forming substrate during a use session. The aerosol generating device comprises a power supply for supplying power to a heating element to heat the aerosol-forming substrate, and a controller. The method includes monitoring a user interaction parameter indicative of use of the aerosol generating device during the use session, and using the user interaction parameter as a parameter for controlling the temperature of the heating element during the use session. Thus, the temperature of the heating element during the use session can be controlled by reference to the manner of use of the user during the use session.

The user interaction parameter may indicate the puffs taken by the user during a use session or the number of puffs taken by the user. The user interaction parameter may also indicate the volume of aerosol generated during a use session.

The value of the user interaction parameter may be associated with the target operating temperature of the heating element.

The user interaction parameter may increase over the duration of the use session. Accordingly, a cumulative value of the user interaction parameter may be recorded during the use session. The cumulative value of the user interaction parameter recorded during the use session may be associated with a target operating temperature of the heating element. The cumulative value of the user interaction parameter may have a predetermined maximum threshold, and when the maximum threshold is reached during the use session, the use session may be terminated.

By associating a user interaction parameter, or an accumulated value of the user interaction parameter, with a corresponding target operating temperature of the heater, it may be possible to adjust the target operating temperature of the heater to take into account the particular usage characteristics of an individual user. This contrasts with the known devices and thermal profiles discussed above, in which the heater temperature varies depending on the time elapsed in a usage session. The ability to adjust the target operating temperature of the heater according to the particular usage characteristics of an individual user may enable more efficient extraction of aerosol from an aerosol-forming substrate. In this way, efficient aerosol extraction from the substrate may be achieved regardless of (or less dependent on) the manner in which an individual user interacts with the aerosol-generating device. Thus, a user may be able to extract substantially all available aerosol from the substrate, for example, without being limited to applying an ideal puff at a predetermined rate. These advantages may also provide the user with an enhanced user experience over a usage session.

As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, such as part of a smoking article. The aerosol-generating device may include one or more components that are used to provide energy from a power source to the aerosol-forming substrate to generate an aerosol. For example, the aerosol-generating device may be a heated aerosol-generating device. The aerosol-generating device may be an electrically heated aerosol-generating device or a gas-heated aerosol-generating device. The aerosol-generating device may also be a smoking device that interacts with the aerosol-forming substrate of the aerosol-generating article to generate an aerosol that can be inhaled directly into the user's lungs through the user's mouth.

As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may be solid or liquid, or may contain both solid and liquid components. The aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. The aerosol-forming substrate may conveniently be part of an aerosol-generating article or a smoking article.

The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise tobacco, e.g., a tobacco-containing material containing volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may comprise homogenized tobacco material, e.g., cast leaf tobacco. The aerosol-forming substrate may comprise at least one aerosol former, such as propylene glycol or glycerin.

As used herein, the term "use session" refers to a period of time during which a user applies a series of puffs to extract an aerosol from an aerosol-forming substrate.

As used herein, the term "cumulative aerosol volume" refers to the cumulative volume of aerosol generated during a use session compared to the start of that use session.

A use session may include multiple use session phases, each of which terminates when the cumulative value of a user interaction parameter reaches a predetermined threshold for that one of the multiple use session phases. A use session may consist of 4 to 20 use session phases, preferably 8 to 14 use session phases, e.g., 10, 11, 12, 13, 14, or 15 use session phases. Each use session phase may terminate when the value of the user interaction parameter, or the cumulative value of the user interaction parameter, meets a predetermined threshold. Such thresholds may be referred to as intermediate thresholds when reached during a use session. For example, a first use session phase may terminate after the cumulative volume of aerosol generated since the start of the use session reaches a first predetermined threshold; a second use session phase subsequent to the first use session phase may terminate after the cumulative volume of aerosol generated since the start of the use session reaches a second predetermined threshold, and so on until the end of the use session.

A use session may include multiple use session stages, each of which terminates when a cumulative value of a second user interaction parameter, different from the user interaction parameter, reaches a predetermined threshold for one of the multiple use session stages. Therefore, the second user interaction parameter controlling progression through the multiple use session stages may be different from the user interaction parameter used to control the temperature of the heating element. For example, the second user interaction parameter may represent the number of puffs the user takes during the use session, and the user interaction parameter may represent the volume of aerosol generated during the use session. In one embodiment, each user puff may be considered a use session stage.

Advantageously, each use session phase may be associated with a target operating temperature for the heating element. Thus, during a first use session phase, the heating element may have a first target operating temperature, and during a second use session phase, the heating element may have a second target operating temperature. The second target operating temperature may be higher than the first target operating temperature, lower than the first operating temperature, or the same as the first operating temperature.

Advantageously, the aerosol generating device may store a predetermined thermal profile that defines the heating element temperature in relation to the value of the monitored user interaction parameter, e.g., the cumulative value of the user interaction parameter during a use session. Where the progression of the user interaction parameter during a use session is associated with progression through multiple use session stages, the thermal profile may therefore define the heating element temperature at each of the multiple use session stages. The operating temperature of the heating element during the use session may then be controlled in accordance with the predetermined thermal profile.

The predetermined thermal profile may be stored in a controller used to control the power supply. Alternatively, the predetermined thermal profile may be stored in a memory module accessible to such a controller.

Advantageously, the method may include associating a use session phase with a corresponding target operating temperature of the heater based on the value of the user interaction parameter, and controlling, for the use session phase, the supply of power from the power source to adjust the temperature of the heater to the target operating temperature associated with the use session phase.

The temperature of the heating element may be controlled with reference to the user interaction parameter and the value of at least one further parameter monitored during the use session. The at least one further parameter may be time. Thus, the temperature of the heating element may be controlled with reference to both the user interaction parameter and the value of time monitored during the use session. In this way, it may be possible to control the temperature of the heating element to take into account both the change in the value of the user interaction parameter and the rate of change of the value of the user interaction parameter. Depending on the rate of change of the user interaction parameter, the controller may apply a positive or negative correction to the target operating temperature suggested by the predetermined thermal profile. For example, a use session may be divided into six use session phases determined by the cumulative value of the aerosol volume generated during the use session.

Each use session phase may be associated with a target operating temperature of the heating element according to a predetermined thermal profile. The predetermined thermal profile may provide an optimized thermal profile for aerosol generation over the duration of the use session. The predetermined thermal profile may provide an optimized thermal profile for aerosol generation over the duration of the use session when a user interacts with the aerosol generating device according to the predetermined usage profile. The predetermined usage profile may provide an expected progression of a user interaction parameter over the duration of the use session. However, the user may interact with the aerosol generating device in a manner that causes the real-time value of the user interaction parameter to differ from that predicted by the predetermined usage profile. In this situation, the controller may be programmed to make modifications to the predetermined thermal profile to account for variations in the actual value of the user interaction parameter at a point in time during the use session compared to the expected value of the user interaction parameter at that point in time as predicted by the predetermined usage profile.

As an example, a predetermined thermal profile may be optimized for a predetermined rate of aerosol generation during a use session. The predetermined rate of aerosol generation may be provided as a predetermined use profile. However, if a user takes heavy or frequent puffs, aerosol may be generated at a rate higher than that expected by the predetermined use profile. In this situation, a target operating temperature, e.g., a target operating temperature associated with one of the use phases, may be modified to account for the higher rate of aerosol generation. Such a correction may be triggered, for example, if the time between the start of one use session phase and the start of the next use session phase is shorter than a predetermined time. Conversely, if a user takes weaker or less frequent puffs, aerosol may be generated at a rate lower than the expected consistent rate. In this situation, a target operating temperature, e.g., a target operating temperature associated with one of the use phases, may be modified to account for the lower rate of aerosol generation. Such a correction may be triggered, for example, if the time between the start of one use session phase and the start of the next use session phase is longer than a predetermined time. Thus, the temperature of the heating element may be controlled with respect to both the value of the user interaction parameter and time, e.g., the value of the user interaction parameter and a value indicative of the rate of change of the user interaction parameter. Modification of the target operating temperature may be triggered by differences in the time interval between successive puffs. Modification of the target operating temperature may be triggered by differences in the rate of aerosol generation during a use session. Depending on the manner in which the user interacts with the device over the duration of the use session, the target operating temperature may be modified to be higher for some portions of the use session and lower for other portions of the use session.

The method may therefore include monitoring a user interaction parameter indicative of use of the aerosol generating device during a use session, where the value of the user interaction parameter is associated with a target operating temperature of the heating element; monitoring a further parameter (e.g., time); and using the user interaction parameter and the further parameter (e.g., time) to control the temperature of the heating element during the use session. The controller may be programmed to use the monitored value of the further parameter to determine whether a modification of the target operating temperature has been implemented. The controller may be programmed to use a value indicative of a rate of change of the user interaction parameter to determine whether a modification of the target operating temperature has been implemented.

Advantageously, the user interaction parameter may be indicative of a volume of aerosol emitted by the aerosol-forming substrate during a use session. The method may, for example, include the steps of monitoring a parameter indicative of aerosol generation during a use session; analyzing the monitored parameter indicative of aerosol generation to identify a user puff, where the user puff is defined by a start of a puff and an end of a puff; analyzing the monitored parameter indicative of aerosol generation during the user puff to calculate a puff volume, where the puff volume is the volume of aerosol generated during the user puff; and using the puff volume as the user interaction parameter for controlling the temperature of the heater element.

The method may include analyzing monitored parameters indicative of aerosol generation to identify multiple user puffs taken during a use session, each of the multiple user puffs having a puff start and a puff end determined by analyzing the monitored parameters indicative of aerosol generation. The method may further include analyzing the monitored parameters indicative of aerosol generation during each of the multiple identified user puffs to calculate a puff volume for each of the multiple user puffs; determining a cumulative puff volume of aerosol generated during each of the multiple identified user puffs; and using the cumulative puff volume as a user interaction parameter for controlling the temperature of the heater element.

An aerosol-forming substrate, such as an aerosol-generating article, may have a maximum volume of aerosol intended to be delivered during a use session. As the aerosol is depleted from the aerosol-forming substrate, the optimal aerosol-generation temperature may change. The rate at which aerosol is delivered during a use session may be significantly affected by how the user interacts with the device during the use session. For example, a user who takes more puffs in a short period of time may deplete the available aerosol faster than a user who takes fewer puffs in the same period of time, assuming the intensity of the puffs remains the same. Similarly, a user who takes 10 long puffs or high-intensity puffs may deplete the available aerosol faster than a user who takes 10 short puffs or low-intensity puffs. Controlling the operating temperature of the heating element during a use session with reference to a user interaction parameter indicative of the volume of aerosol generated may allow for optimization of the operating temperature over the duration of the use session, regardless of how the user interacts with the device.

The volume of aerosol generated in response to an applied puff may be determined directly or indirectly. The volume may be determined directly by using an airflow sensor or the like. However, the volume is preferably determined indirectly by using a parameter indicative of aerosol generation during a use session. The parameter indicative of aerosol generation may be representative of power supplied by a power source. The current, or voltage, or both current and voltage supplied to a heater may be parameters representative of power. For example, a power source may provide power to maintain a heater at a predetermined temperature during a use session. When a user puffs on the device to generate aerosol, the heater cools and requires more power to maintain the heater at the predetermined temperature. Therefore, by monitoring a parameter representative of power supplied by the power source, a value indicative of real-time aerosol generation may be recorded. A function of the monitored parameter indicative of aerosol generation may be calculated and evaluated in real time to determine puff volume.

The step of analyzing the monitored parameters may include calculating a first characteristic of the monitored parameters and analyzing the first characteristic to determine puff onset and puff cessation. The step of analyzing the monitored parameters may include calculating a second characteristic of the monitored parameters and analyzing both the first characteristic and the second characteristic to determine puff onset and puff cessation. The more accurately puff onset and puff cessation can be determined, the more accurately the puff volume can be calculated.

When the first characteristic and the second characteristic satisfy one or more predetermined conditions, it may be determined that the start of a puff has occurred. When the first characteristic and the second characteristic satisfy one or more predetermined conditions, it may be determined that the end of a puff has occurred.

The first characteristic may be a first moving average, a first moving median, or any other suitable signal characteristic value of the monitored parameter calculated over a first time window having a duration of the first time window. The second characteristic may be a second moving average, a second moving median, or any other suitable signal characteristic value of the monitored parameter calculated over a second time window having a duration of a second time window, the duration of the second time window being different from the duration of the first time window.

The onset of a puff may be determined when a first characteristic, e.g., a first moving average, and a second characteristic, e.g., a second moving average, satisfy a predetermined relationship with respect to one another. For example, the duration of the first time window may be shorter than the duration of the second time window, and the onset of a puff may be determined when the first moving average increases relative to the second moving average and reaches a puff onset value (where the first moving average is equal to the second moving average plus a first predetermined puff onset constant).

The end of a puff may be determined when a first characteristic, e.g., a first moving average, and a second characteristic, e.g., a second moving average, satisfy a predetermined relationship with respect to one another. For example, the end of a puff may be determined when the first moving average decreases relative to the second moving average after detecting the start of a puff and reaches an end of puff value (where the first moving average is greater than the second moving average minus a first predetermined end of puff constant, and the second moving average is less than the second moving average at the start of the puff plus the second predetermined end of puff constant).

The or each puff may be determined by integrating a curve representing the monitored parameter as a function of the time between the start of the or each puff and the end of the or each puff. The or each cumulative puff may be used as a user interaction parameter.

The first characteristic may be a first moving average value of the monitored parameter calculated over a first time window having a first time window duration. The duration of the first time window is preferably between 20 ms and 1000 ms, for example, between 100 ms and 500 ms, or between 200 ms and 500 ms. The duration of the first time window may be about 250 ms, or about 300 ms, or about 350 ms, or about 400 ms, or about 450 ms.

The second characteristic may be a second moving average value of the monitored parameter calculated over a second time window having a second time window duration, the second time window duration being different from the first time window duration. The second time window duration is preferably between 100 ms and 2000 ms, e.g., between 500 ms and 1500 ms, or between 800 ms and 1400 ms. The second time window duration may be about 850 ms, or about 900 ms, or about 950 ms, or about 1000 ms, or about 1050 ms, or about 1100 ms, or about 1200 ms.

The duration of the first time window may be shorter than the duration of the second time window, and the onset of a puff may be determined when the first moving average increases relative to the second moving average and reaches a puff onset value (where the first moving average is equal to the second moving average plus a first predetermined puff onset constant). The puff onset constant may preferably be an empirically determined constant. Alternatively, the puff onset constant may be a calculated constant.

The end of a puff may be determined when the first moving average decreases relative to the second moving average after detecting the start of a puff and reaches an end of puff value (where the first moving average is greater than the second moving average minus a first predetermined puff termination constant, and the second moving average is less than the second moving average at the start of the puff plus the second predetermined puff termination constant). The first predetermined puff termination constant and the second predetermined puff termination constant may preferably be empirically determined constants. Alternatively, the first predetermined puff termination constant and the second predetermined puff termination constant may be calculated constants.

General noise in a monitored parameter may mean that the criteria for the start of a puff are met when a true puff is not occurring. To minimize recording such events as puffs, one or more predetermined verification conditions may be required to be met to verify that a puff has occurred once the start of a puff has been determined. A verification condition may be referred to as a trigger. A puff is not recorded unless the or each verification condition is met. As one example, once the start of a puff has been determined, a valid puff may be recorded only if a first verification condition is met and the end of the puff is detected. As a further example, once the start of a puff has been determined, a valid puff may be recorded only if a first verification condition is met, a second verification condition is met, and the end of the puff is detected.

According to one aspect of the present invention, there is provided an aerosol generation device for generating an aerosol from an aerosol-forming substrate during a use session. The aerosol generation device comprises a power supply for providing power to generate the aerosol, and a controller configured to monitor a user interaction parameter indicative of use of the aerosol generation device during the use session, and to use the user interaction parameter to control the temperature of the heating element during the use session. The aerosol generation device may be configured to perform any of the methods described above.

The aerosol generating device may be configured to monitor parameters indicative of aerosol generation during operation of the aerosol generating device and to analyze the monitored parameters to identify a user puff. A user puff may be defined by the start of a puff and the end of the puff. The aerosol generating device may be configured to analyze the monitored parameters during the user's puff to calculate a puff volume, which is the volume of aerosol generated during the user's puff. The aerosol generating device may be configured to control the temperature of the heating element based on the calculated puff volume.

The aerosol generating device may be configured to control the temperature of the heating element during a use session by referring to the cumulative amount of puffs generated during the use session. The aerosol generating device may be configured to control the temperature of the heating element during a use session by referring to the rate of change of the cumulative amount of puffs generated during the use session. The aerosol generating device may be configured to control the temperature of the heating element during a use session by referring to both the cumulative amount of puffs generated during the use session and the rate of change of the cumulative amount of puffs generated during the use session.

The aerosol-generating device may include a heater, and the monitored parameter may be, or may represent, the power supplied to the heater during operation of the aerosol-generating device. The heater may be an induction heater, and the monitored parameter may represent the energy absorbed by a susceptor. The heater may be a resistance heater, and the monitored parameter may represent the energy supplied to the resistance heater. The aerosol-generating device is preferably configured to receive an aerosol-generating article that includes an aerosol-forming substrate. The heating element may be provided within the aerosol-generating article; for example, the heating element may be a susceptor that forms part of the aerosol-generating article.

According to one aspect of the invention, there is provided an aerosol generating device for generating an aerosol from an aerosol-forming substrate during a use session. The aerosol generating device includes a power supply for providing power to generate the aerosol, and a controller. The aerosol generating device includes a computer-readable medium containing instructions for performing a method of monitoring a user interaction parameter indicative of use of the aerosol generating device during the use session, and a method of using the user interaction parameter as a parameter for controlling the temperature of a heating element during the use session. The computer-readable medium may include instructions for performing any of the methods described above.

The present invention is defined in the claims. However, the following provides 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 any other example, embodiment, or aspect described herein.

Example 1. A method of operating an aerosol generating device for generating an aerosol from an aerosol-forming substrate during a session of use, the aerosol generating device comprising:
a power supply for supplying power to the heating element to heat the aerosol-forming substrate;
a controller;
The method is
monitoring a user interaction parameter indicative of use of the aerosol generating device during a use session;
and using the user interaction parameter as a parameter for controlling the temperature of the heating element during a use session.
Example 2. The method of example 1, wherein the value of the user interaction parameter is associated with a target operating temperature of the heating element.
Example 3. The method of example 1 or example 2, wherein cumulative values of a user interaction parameter recorded during a use session are correlated with a target operating temperature of the heating element.
Example 3A. The method of example 2 or example 3, wherein the controller is configured to monitor a rate of change of the user interaction parameter and to modify the target operating temperature for any value of the user interaction parameter, or for any cumulative value of the user interaction parameter, based on the rate of change of the user interaction parameter.
Example 4. The method of any of Examples 1-3A, wherein the cumulative value of the user interaction parameter has a predetermined maximum threshold, and when the maximum threshold is reached during the use session, the use session is terminated.
Example 5. The method of any of Examples 1-4, wherein the usage session includes a plurality of usage session phases, each of the plurality of usage session phases ending when the cumulative value of the user interaction parameter reaches a predetermined threshold for that one of the plurality of usage session phases.
Example 6. The method of example 5, wherein the use session consists of 4 to 20 use session stages, preferably 8 to 14 use session stages, such as 10, 11, 12, 13, 14 or 15 use session stages.
Example 7. The method of example 5 or example 6, wherein each use session phase is associated with a target operating temperature for the heating element.
Example 8. The method of any of Examples 1-7, wherein the aerosol generating device stores a predetermined thermal profile that defines the heating element temperature versus the value of the monitored user interaction parameter, e.g., the cumulative value of the user interaction parameter during a use session.
Example 9. The method of example 8, wherein the operating temperature of the heating element during a use session is controlled according to a predetermined thermal profile.
Example 10. The method of any of Examples 1-9, wherein the temperature of the heating element is controlled with reference to a user interaction parameter and the value of at least one further parameter monitored during a session of use.
Example 11. The method of example 10, wherein the temperature of the heating element is controlled with reference to a user interaction parameter and a time value monitored during a use session.
Example 11A. The method of Example 11, wherein the temperature of the heating element is controlled at least in part by reference to the rate of change of a user interaction parameter.
Example 12. The method of any of Examples 1-11A, wherein the user interaction parameter is indicative of the volume of aerosol emitted by the aerosol-forming substrate during a use session.
Example 13. Monitoring a parameter indicative of aerosol generation during a use session;
analyzing the monitored parameters indicative of aerosol generation to identify a user puff, wherein a user puff is defined by a start of a puff and an end of a puff;
analyzing monitored parameters indicative of aerosol generation during a user's puff to calculate a puff volume, the puff volume being the volume of aerosol generated during a user's puff;
and using the puff volume as a user interaction parameter to control the temperature of the heater element.
Example 14. The method of any of Examples 1-14, comprising analyzing monitored parameters indicative of aerosol generation to identify multiple user puffs taken during a use session, each of the multiple user puffs having a puff start and a puff end determined by analyzing the monitored parameters indicative of aerosol generation.
Example 15. The method of Example 14, comprising analyzing monitored parameters indicative of aerosol generation during each of a plurality of identified user puffs to calculate a puff for each of the plurality of user puffs, determining a cumulative puff of aerosol generated during each of the plurality of identified user puffs, and using the cumulative puff as a user interaction parameter for controlling the temperature of the heater element.
Example 16. The method of any of Examples 1-15, wherein a function of monitored parameters indicative of aerosol generation is calculated and evaluated in real time to determine smoke puff yield.
Example 17. The method of any of Examples 1-16, wherein the step of analyzing the monitored parameter indicative of aerosol generation comprises calculating a first characteristic of the monitored parameter indicative of aerosol generation and analyzing the first characteristic to determine puff start and puff cessation.
Example 18. The method of Example 17, wherein the step of analyzing the monitored parameter indicative of aerosol generation comprises calculating a second characteristic of the monitored parameter indicative of aerosol generation, and analyzing both the first characteristic and the second characteristic to determine puff onset and puff cessation.
Example 19. The method of example 18, wherein the initiation of a puff is determined when the first characteristic and the second characteristic satisfy one or more predetermined conditions.
Example 20. The method of example 19 or example 20, wherein the end of the puff is determined when the first characteristic and the second characteristic satisfy one or more predetermined conditions.
Example 21. The method of any of Examples 17-20, wherein the first characteristic is a first moving average value of the monitored parameter calculated over a first time window having a first time window duration.
Example 22. The method of any of Examples 18-21, wherein the second characteristic is a second moving average value of the monitored parameter indicative of aerosol generation calculated over a second time window having a duration of the second time window, the duration of the second time window being different from the duration of the first time window.
Example 23. The method of example 22, wherein the onset of a puff is determined when the first moving average value and the second moving average value satisfy a predetermined relationship with respect to one another.
Example 24. The method of Example 23, wherein the duration of the first time window is less than the duration of the second time window, and the onset of a puff is determined when the first moving average increases relative to the second moving average and reaches a puff onset value (where the first moving average is equal to the second moving average plus a first predetermined puff onset constant).
Example 25. The method of Example 24, wherein the end of a puff is determined when the first moving average decreases relative to the second moving average after detecting the start of a puff and reaches an end of puff value (wherein the first moving average is greater than the second moving average minus a first predetermined end of puff constant and the second moving average is less than the second moving average at the start of the puff plus a second predetermined end of puff constant).
Example 26. The method of any of Examples 17-20, wherein the first characteristic is a first running median of a monitored parameter indicative of aerosol generation calculated over a first time window having a duration of the first time window.
Example 27. The method of any of Examples 18-21 and Example 26, wherein the second property is a second running median of the monitored parameter indicative of aerosol generation calculated over a second time window having a duration of the second time window, the duration of the second time window being different from the duration of the first time window.
Example 28. The method of example 27, wherein the onset of a puff is determined when the first moving median and the second moving median satisfy a predetermined relationship with respect to each other.
Example 29. The method of Example 28, wherein the duration of the first time window is less than the duration of the second time window, and the onset of a puff is determined when the first moving median increases relative to the second moving median and reaches a puff onset value, where the first moving median is equal to the second moving median plus a first predetermined puff onset constant.
Example 30. The method of Example 29, wherein the end of a puff is determined when the first moving median decreases relative to the second moving median after detecting the start of a puff and reaches an end of puff value, where the first moving median is greater than the second moving median minus a first predetermined puff termination constant, and the second moving median is less than the second moving median at the start of the puff plus the second predetermined puff termination constant.
Example 31. The method of any of Examples 1-30, wherein the monitored parameters indicative of aerosol generation are analyzed to detect at least one verification condition (or trigger) occurring after the start of a puff and before the end of the puff, and wherein detection of the at least one verification condition (or trigger) is required for a valid puff to be recorded.
Example 32. The method of example 31, wherein the verification condition (or trigger) is determined when the first characteristic and the second characteristic satisfy one or more predetermined conditions.
Example 33. The method of any of Examples 1-32, wherein the or each puff is determined by integration of a curve representing a monitored parameter indicative of aerosol generation as a function of the time between the start of the or each puff and the end of the or each puff.
Example 34. An aerosol generation device for generating an aerosol from an aerosol-forming substrate during a use session, the aerosol generation device comprising: a power source for providing power to generate the aerosol; and a controller configured to monitor a user interaction parameter indicative of use of the aerosol generation device during the use session, and to use the user interaction parameter to control the temperature of the heating element during the use session.
Example 35. An aerosol generating device according to example 34, configured to carry out a method as defined in any of examples 1 to 33.
Example 36. The aerosol generating device of example 34 or example 35, wherein the device is configured to monitor parameters indicative of aerosol generation during operation of the aerosol generating device, analyze the monitored parameters to identify a user puff defined by a start of a puff and an end of a puff, analyze the monitored parameters during the user's puff to calculate a puff volume, which is the volume of aerosol generated during the user's puff, and control the temperature of the heating element based on the calculated puff volume.
Example 37. An aerosol generating device according to any of Examples 34 to 36, wherein the device comprises a heater and the monitored parameter is, or is representative of, the power supplied to the heater during operation of the aerosol generating device.
Example 38. The aerosol generating apparatus of Example 37, wherein the heater is an induction heater, the heating element is a susceptor, and the monitored parameter is representative of energy absorbed by the susceptor.
Example 39. The aerosol generating device of Example 37, wherein the heater is a resistive heater, the heating element is a resistive heating element, and the monitored parameter is representative of energy supplied to the resistive heater.
Example 40. The aerosol-generating device of any of Examples 34 to 39, configured to receive an aerosol-generating article comprising an aerosol-forming substrate.
Example 41. The aerosol generating device of Example 40, wherein the heating element is provided within the aerosol-generating article, for example, the heating element is a susceptor provided within the aerosol-generating article.
Example 42. An aerosol generation device for generating an aerosol from an aerosol-forming substrate during a use session, the aerosol generation device comprising: a power source for providing power to generate the aerosol; and a controller, the aerosol generation device comprising a computer readable medium comprising instructions for performing a method of monitoring a user interaction parameter indicative of use of the aerosol generation device during the use session, and using the user interaction parameter as a parameter for controlling the temperature of the heating element during the use session.
Example 43. An aerosol generation device for generating an aerosol from an aerosol-forming substrate during a session of use, the aerosol generation device comprising: a power supply for providing power to generate the aerosol; and a controller; and the aerosol generation device comprising a computer-readable medium comprising instructions for performing the method of any of Examples 1 to 33.

The example will now be further described with reference to the following figures:

FIG. 1 illustrates a schematic side view of an aerosol generating device. FIG. 2 illustrates a schematic top view of the aerosol generating device of FIG. FIG. 3 illustrates a schematic cross-sectional side view of the aerosol generating device of FIG. 1 and an aerosol-generating article for use with the aerosol generating device. FIG. 4 illustrates a method according to the present disclosure in which the target operating temperature of the heater is adjusted depending on the cumulative aerosol volume generated during a use session. FIG. 5 illustrates a thermal profile according to the present disclosure in which the target operating temperature of the heater is defined as a function of the cumulative aerosol volume generated during a use session. FIG. 6 is a flow chart illustrating a method for controlling the operating temperature of an aerosol generating device by detecting puffs and calculating the cumulative aerosol volume generated during a use session. FIG. 7 is a graph illustrating power as a function of time during a user's puff and two moving averages of the power curve, specifically illustrating the detection points of a puff. FIG. 8 is a graph illustrating power as a function of time during a user's puff and two moving averages of the power curve, specifically illustrating the second trigger point. FIG. 9 is a graph illustrating power as a function of time during a user's puff and two moving averages of the power curves, specifically illustrating the detection of the end of the puff. FIG. 10 is a graph illustrating the detection of a puff, including identification of various trigger points used to verify a puff. FIG. 11 is a graph illustrating the calculation of energy by integrating the power signal during a detected puff.

The exemplary aerosol generating device 10 is a handheld aerosol generating device and has an elongated shape defined by a substantially circular, cylindrical housing 20 (see FIGS. 1, 2, and 3). The aerosol generating device 10 includes an open cavity 25 located at the proximal end 21 of the housing 20 for receiving an aerosol-generating article 30 including an aerosol-forming substrate 31. The aerosol generating device 10 includes a battery 26, control electronics 27, and a memory module 28 located within the housing 20. The memory module 28 is readable and writable during use. An electrically operated heater 40 is disposed within the device 10 for heating at least the aerosol-forming substrate portion 31 of the aerosol-generating article 30 when the aerosol-generating article is received within the cavity 25. The memory module 28 stores a thermal profile accessible to the control electronics 27 during use of the device 10. The thermal profile defines how the target operating temperature of the heater 40 changes over a use session.

The aerosol-generating device is configured to receive a consumable aerosol-generating article 30. The aerosol-generating article 30 is in the form of a cylindrical rod and includes an aerosol-forming substrate 31 (see FIG. 3). The aerosol-forming substrate 31 is a solid aerosol-forming substrate that includes tobacco. The aerosol-generating article 30 further includes a mouthpiece, such as a filter 32, disposed within the cylindrical rod in coaxial alignment with the aerosol-forming substrate 31. The aerosol-generating article 30 has a diameter substantially equal to the diameter of the cavity 25 of the device 10 and a length greater than the depth of the cavity 25, such that when the article 30 is received within the cavity 25 of the device 10, the mouthpiece 32 extends outside the cavity 25 and may be withdrawn by the user in the same manner as a conventional cigarette.

During use, a user inserts the article 30 into the cavity 25 of the aerosol-generating device 10 and turns on the device 10 by pressing the user button 50 (see FIG. 1 ) to activate the heater 40 to begin a use session. The heater 40 heats the aerosol-forming substrate 31 of the article 30, causing volatile compounds in the aerosol-forming substrate to be released and atomized to form an aerosol. The user draws on the mouthpiece of the article 30 and inhales the aerosol generated from the heated aerosol-forming substrate 31. After activation, the temperature of the heater 40 is increased from ambient temperature to a predetermined temperature to heat the aerosol-forming substrate. The predetermined temperature is defined in a thermal profile stored in the memory 28. After activation and during the course of a use session, the control electronics 27 of the device 10 accesses the thermal profile stored in the memory module 28 to control the supply of power from the battery 26 to the heater 40 and adjust the heater temperature according to the thermal profile. The heater 40 continues to heat the aerosol-generating article 30 until the end of the use session, at which point the heater is deactivated and allowed to cool. In certain embodiments, the heater 40 may be a resistive heating element. In certain embodiments, the heater 40 may be a susceptor disposed within a varying magnetic field so as to be heated by induction.

At the end of the usage session, the item 30 may be removed from the device 10 for disposal, and the device 10 may be connected to an external power source to charge the device 10's battery 26.

The aerosol-generating article 30 used with the device 10 has a finite amount of aerosol-forming substrate 31, and therefore, a use session must have a finite duration to prevent a user from attempting to generate aerosol when the aerosol-forming substrate 31 is depleted. A use session is configured to have a maximum duration determined by the longest period from the start of the use session. A use session is also configured to have a duration shorter than the maximum period if a user interaction parameter recorded during the use session reaches the threshold before the maximum period has elapsed. In one particular embodiment, the user interaction parameter represents the cumulative volume of aerosol generated over the duration of the use session. A maximum aerosol generation threshold, e.g., 660 ml, is defined for the cumulative volume of aerosol. Thus, in this particular embodiment, the aerosol generating device 10 is configured so that each use session has a maximum duration defined by either i) six minutes from activation of the use session or ii) the generation of a total of 660 ml of aerosol during the use session, whichever occurs first.

Figure 4 schematically illustrates a method 100 according to the present disclosure. Method 100 is performed by the aerosol generating device 10 of the present disclosure when a user applies a series of puffs to the aerosol generating device 10 during a use session. During each puff, a volume of aerosol is generated. The volume of the generated aerosol is calculated, and the cumulative volume of aerosol is recorded over the duration of the use session. The cumulative volume of aerosol is used as a user interaction parameter. In step 101, a first threshold cumulative volume of aerosol is associated with a corresponding target operating temperature of the heater 40. In step 102, the supply of power from the battery 26 is controlled by the control electronics 27 to adjust the temperature of the heater 40 to the target operating temperature associated with the first threshold volume of aerosol generated.

Steps 101 and 102 of method 100 are repeated for second, third, and fourth threshold cumulative volumes of aerosol, and so on, until the end of the use session. Method 100 thereby enables the temperature of heater 40 to be adjusted depending on the cumulative volume of aerosol generated during the use session.

Method 100 may be implemented by a combination of control electronics 27 and a thermal profile stored in memory module 28. During the course of a usage session, control electronics 27 will access memory module 28 to read the thermal profile and then control the supply of power from power source 26 to regulate the temperature of heater 40 according to the instructions provided in the thermal profile.

FIG. 5 illustrates an example thermal profile for use in practicing a method as disclosed herein, e.g., using the aerosol generating device 10 to practice the method of FIG. 4. The thermal profile of FIG. 5 defines a target operating temperature for each of multiple thresholds of cumulative aerosol volume generated during a use session. The thermal profile is preferably stored within the memory module 28 of the aerosol generating device 10. As a user applies each puff of a series of puffs to the device 10, a volume of aerosol is generated, and the cumulative volume of the aerosol is determined, e.g., by calculation or flow measurement. The control electronics 27 accesses the memory 28 to read the thermal profile, and then controls the supply of power from the battery 26 to the heater 40 to adjust the target operating temperature of the heater according to the thermal profile of FIG. 5 and the cumulative volume of aerosol generated during the use session. Thus, taking the thermal profile of FIG. 5 as an example, a use session may have a maximum aerosol volume threshold of 660 ml. Once 660 ml of aerosol has been generated, the use session ends. A use session may be divided into multiple stages, each ending when a threshold cumulative volume of aerosol generated during the use session is reached. As an example, a use session may be divided into 12 stages, each ending after a threshold volume of 55 ml of aerosol is generated. Thus, a first stage may end after a first threshold cumulative volume of 55 ml of aerosol is generated, a second stage may end after a second threshold cumulative volume of 110 ml of aerosol is generated, a third stage may end after a third threshold cumulative volume of 165 ml of aerosol is generated, and so on until the end of the use session. In the exemplary thermal profile illustrated in FIG. 5 , the heater temperature is initially raised to a target operating temperature of 350°C. After a cumulative volume of 55 ml of aerosol is generated, the target operating temperature is lowered to 320°C. After a cumulative volume of 275 ml of aerosol is generated, the target operating temperature is raised to 326°C. After generating a cumulative volume of 385 ml of aerosol, the target operating temperature is increased to 332°C. After generating a cumulative volume of 440 ml of aerosol, the target operating temperature is increased to 338°C. After generating a cumulative volume of 495 ml of aerosol, the target operating temperature is increased to 344°C. After generating a cumulative volume of 550 ml of aerosol, the target operating temperature is increased to 350°C. The operating temperature remains at 350°C until the end of the use session.

The volume of aerosol generated, and the cumulative volume of aerosol generated over the duration of a use session, may be determined by measuring the airflow through the device. For example, an airflow sensor, or airflow sensing means, may provide the volume of airflow, and the volume of aerosol generated may be calculated from this volume of airflow. Conveniently, the volume of aerosol generated, and the cumulative volume of aerosol generated, may be determined by monitoring a signal representative of the power supplied to the heater, determining user puffs by interpreting fluctuations in the signal representative of the power supplied to the heater, and calculating the volume of aerosol associated with each user puff. An advantageous method for determining the volume of aerosol generated may be as follows:

An exemplary method overview is illustrated diagrammatically in FIG. 6. A user initiates a use session by inserting an aerosol-generating article into the aerosol generating device and activating the user button 50, marking the start of the user experience 601. Power is supplied to the heater element 40 from a battery within the aerosol generating device until the heater element reaches an initial operating temperature. This temperature may be, for example, approximately 330°C, following the temperature profile of FIG. 5.

The power signal of the power supplied to the heater is monitored (602). The user then takes a puff (603). As the user puffs, the heater cools due to airflow. Therefore, the power that needs to be supplied to the heater to maintain the operating temperature increases. The power supplied is increased and the correct temperature is maintained.

The presence of a user puff is detected by analyzing the power signal 604. The start and end points of the puff are determined by this analysis.

The energy of the detected puff is then calculated (605), as is the volume of aerosol generated during the puff (606). The volumes generated during each puff are added together to provide a cumulative total of the volumes generated during the usage session 607.

If, in query step 608, the cumulative total volume equals or exceeds a predetermined maximum allowable aerosol volume for the use session (e.g., 660 ml), the use session is terminated (609).

If the cumulative total volume does not equal or exceed the predetermined maximum allowable aerosol volume for the use session, then in a further query step 610, the controller determines whether the cumulative total volume equals or exceeds a set intermediate threshold for modifying the heater's operating temperature. If not, the process returns to step 602. The session remains active and the user may take another puff.

If the cumulative total volume equals or exceeds such an intermediate threshold (e.g., the 275 ml threshold shown in FIG. 5), the heater's operating temperature is changed (e.g., increased to 326°C as shown in FIG. 5) and the process returns to step 602. The session remains active and the user can take another puff, but the operating temperature has been changed.

The use session remains active until the user generates the maximum allowable aerosol volume or until the maximum time threshold is reached. During the use session, the heater's operating temperature varies as different intermediate thresholds of cumulative aerosol volume are met, for example, as described above with respect to FIG. 5.

Many factors affect the power signal under operating conditions, and the power as a function of time in an aerosol generating device is noisy and complex. In practical applications, the power signal is subject to background noise, and it is not easy to reliably associate specific behavior with the generation of a puff. A simple threshold analysis of the power signal to determine a puff may only allow for an approximate quantification of the volume of aerosol generated. While an approximate quantification may allow for control of the temperature as a function of the aerosol volume generated, which significantly benefits the user experience, in some situations it may be desirable to provide a more accurate quantification of the aerosol volume generated.

Two moving averages of power as a function of time may be compared to provide a more accurate determination of the start and end of a puff, and therefore a more accurate quantification of cumulative aerosol volume. The relationship between the two moving averages may be analyzed in real time, and specific points, including the start and end of a puff, may be determined. The specific points determined by analysis of the two moving averages may be referred to as trigger points.

Figure 7 shows a graph illustrating the power supplied to the heater as a function of time. The function P (power) of time has a trend depicted as a rectangular curve 501 on the graph.

The first moving average 502 (MA1) is the average value of the power signal over the first time window TW1, which in this particular example is approximately 400 ms.

The second moving average 504 (MA2) is the average value of the power signal over the second time window TW2, which in this particular example is approximately 1000 ms.

In the first portion of graph 503, the heater is at a constant temperature and the user is not puffing. Therefore, the power supplied to the heater to maintain the operating temperature is constant and equal to the value shown as A on the graph. In the first portion of graph 503, because power is constant and equal to the value A, the value of first moving average 502 matches the value of power 501, and therefore the average value over time window TW1 is also constant over time. In the first portion of graph 503, because power is constant and equal to the value A, the value of second moving average 504 matches the value of power 501, and therefore the average value over time window TW2 is also constant over time.

As the user takes a puff, the heater is cooled by the resulting airflow. Therefore, the power supplied to the heater must increase to maintain the heater at its operating temperature. As depicted in Figure 7, the power increases from a value labeled A to a higher value labeled B. Once the user completes their puff, the power required to supply the heater to maintain operating temperature decreases, and the supplied power decreases back to the maintenance level labeled A.

After the power increases, the first moving average gradually increases, but not as rapidly as the power signal because it still includes the portion of the signal that is at value A. The first moving average continues to increase until it matches the power value. The first moving average then decreases again after the power decreases again.

After the power increase, the second moving average gradually increases. Because the second moving average is based on a longer time window TW2 than the first moving average, the second moving average begins to rise near the puff region, but does so more slowly than the first moving average.

Given the first and second moving averages, conditions may be established to detect a puff. First, a significant event, identified as a moving average crossover, is defined: MA1 = MA2 + δ1. An event is called a moving average crossover when the first moving average is equal to the second moving average plus a first constant (δ1). The constant δ1 is an experimentally determined value. According to a preferred specific embodiment, the first constant (δ1) is 0.22 W. The onset of a puff is determined to occur when the relationship between the first and second moving averages meets or exceeds the condition defined for a moving average crossover. That is, the onset of a puff is determined to occur when the relationship between the first and second moving averages changes from MA1 < MA2 + δ1 to MA1 = MA2 + δ1 or MA1 > MA2 + δ1. A moving average crossover corresponds to a perturbation in the power signal that is large enough to be quantified as a puff. This method has advantages when the power signal carries a large amount of background noise, and behavior corresponding to the onset of a puff may not otherwise be easy to detect.

Conditions may also be defined that, when verified, indicate the occurrence of a puff. After a moving average crossover is detected, four conditions (or triggers) may be verified by monitoring the power signal to look for a puff. These verification conditions, or triggers, may be identified as Trigger 1, Trigger 2, Trigger 3, and Trigger 4, and are defined as follows:

Trigger 1: The condition for Trigger 1 is MA1 > MA2 + δ1. Trigger 1 is tied to the start of a puff. When Trigger 1 is detected immediately after a moving average crossover, the system recognizes that such detection corresponds to the start of a puff.

Trigger 2: The condition for Trigger 2 is MA2 > MA1 + δ2. Trigger 2 identifies the peak of the puff, where δ2 is a second constant. According to a preferred specific embodiment, the second constant (δ2) is 0 W. The position of Trigger 2 is illustrated in Figure 8.

Trigger 3: The condition for Trigger 3 is MA2 > MA1 + δ3. This trigger identifies puff fading, where δ3 is the third constant.

Trigger 4: The conditions for Trigger 4 are MA1 > MA2 - δ41, and MA2 < MA2 1ST + δ42. This trigger detects the end of a puff, where δ41 is the fourth constant and δ42 is the fifth constant. δ41 and δ42 are calculated experimentally. According to a preferred specific embodiment, the fourth constant δ41 is 0.06 W, and the fifth constant δ42 is 0.31 W. The conditions for Trigger 4 are illustrated in Figure 9.

Figure 10 illustrates puff detection in a further specific example. For this specific embodiment, the first moving average (MA1) was based on a 128 ms time window, and the second moving average (MA2) was based on a 512 ms time window.

A puff is detected when a moving average crossover occurs (801). This is the point when MA1 = MA2 + δ1, where δ1 is an experimentally determined constant with a value of 0.22W.

The first trigger occurs when MA1 > MA2 + δ1, i.e., immediately after the start of a puff.

The second trigger 802 occurs when MA2 > MA1 + δ2. δ2 is an experimentally determined constant with a value of 0 W. Therefore, the second trigger occurs when MA2 > MA1.

The third trigger 803 occurs when MA2 > MA1 + δ3, where δ3 is an experimentally determined constant with a value of 0.18 W.

The fourth trigger 804 occurs when MA1 > MA2 - δ41 and MA2 < MA2 1ST + δ42. δ41 is an experimentally determined constant having a value of 0.06 W. δ42 is an experimentally determined constant having a value of 0.31 W. The puff is considered to have ended at the fourth trigger.

To improve the accuracy of puff detection, a set of time thresholds may be established between different triggers. Such thresholds facilitate effective detection of puffs at very different volumes and flows. The time threshold, or timeout, is the duration that begins after a trigger is activated. If the following trigger is not activated after a predetermined period, the detection process is reset. This allows for "falsely detected" triggers to be discarded.

A first timeout may begin after the first trigger. If the second trigger is not detected within a predetermined period, puff detection is rejected and the detection system is reset. In one particular embodiment, the first timeout may have a duration of 2.5 seconds. Therefore, if the second trigger is not detected within 2.5 seconds of the first trigger, puff detection is rejected.

A second timeout may begin after the third trigger. If the fourth trigger is not detected within a predetermined period, puff detection is rejected and the detection system is reset. In one particular embodiment, the second timeout may have a duration of 3.5 seconds. Therefore, if the fourth trigger is not detected within 3.5 seconds of the third trigger, puff detection is rejected.

After the end of the puff is identified (fourth trigger), the volume of the puff is calculated from the time integral of the power from the start of the puff to the end of the puff. The integral of power over time is equal to energy. Energy then corresponds to the heat injected into the consumable, and heat is carried away by the user along with a certain amount of cooling airflow.

As illustrated in Figure 11, it should be appreciated that the energy strictly associated with a puff may be calculated as the integral of the power signal during a puff minus the energy that would be consumed anyway even without a puff, as shown in the formula:

Energy is correlated to volume through an empirically determined relationship. Similarly, power can be correlated to airflow, which is equal to volume per unit of time.

A use session, which may be referred to as a user experience, has a maximum allowable cumulative volume of aerosol delivered. Each puff contributes to the cumulative volume. As the cumulative volume reaches various predetermined thresholds during a use session, the operating temperature of the heating element may be varied to optimize aerosol generation from the aerosol-forming substrate.

For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all instances to be modified by the term "about." Also, all ranges include the disclosed maximum and minimum points, and any intermediate ranges therebetween, which may or may not be specifically recited herein. Accordingly, in this context, the number "A" may be understood as "A" ± 10%. Within this context, the number "A" may be considered to include values that are within the usual standard error of measurement for the property that the number "A" modifies. In some cases, as used in the appended claims, the number "A" may deviate by the percentages recited above, provided that the amount by which "A" deviates does not materially affect the basic and novel property(ies) of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and any intermediate ranges therebetween, which may or may not be specifically recited herein.

Claims (15)

1. A method of operating an aerosol generating device for generating an aerosol from an aerosol-forming substrate during a session of use, the aerosol generating device comprising:
a power source for supplying power to a heating element to heat the aerosol-forming substrate;
a controller;
The method comprises:
monitoring a user interaction parameter indicative of use of the aerosol generating device during the use session;
and using the user interaction parameter as a parameter for controlling the temperature of the heating element during the use session;
the method comprising: monitoring a parameter indicative of aerosol generation during the use session;
analyzing the monitored parameters indicative of aerosol generation to identify a user puff, wherein the user puff is defined by a start of a puff and an end of a puff;
analyzing the monitored parameters indicative of aerosol generation during the user's puff to calculate a puff volume, the puff volume being the volume of aerosol generated during the user's puff;
and using the puff volume as the user interaction parameter for controlling the temperature of the heating element . The method of claim 1, wherein the value of the user interaction parameter is associated with a target operating temperature of the heating element, and the cumulative value of the user interaction parameter recorded during the usage session is associated with the target operating temperature of the heating element. A method according to any one of claims 1 to 2, wherein the aerosol generating device stores a predetermined thermal profile defining the heating element temperature relative to the value of the monitored user interaction parameter , the value of the monitored user interaction parameter being, for example, a cumulative value of the user interaction parameter during the usage session . The method of claim 3 , wherein a target operating temperature of the heating element during the use session is controlled according to the predetermined thermal profile. A method according to any one of claims 1 to 4, wherein the user interaction parameter indicates the volume of aerosol emitted by the aerosol-forming substrate during the use session. A method according to any one of claims 1 to 5, comprising analyzing the monitored parameters indicative of aerosol generation to identify multiple user puffs taken during the use session, each of the multiple user puffs having a puff start and puff end determined by analyzing the monitored parameters indicative of aerosol generation. 7. The method of claim 6, comprising: analyzing the monitored parameters indicative of aerosol generation during each of a plurality of identified user puffs to calculate a puff volume for each of the plurality of user puffs; determining a cumulative puff volume of aerosol generated during each of the plurality of identified user puffs; and using the cumulative puff volume as a user interaction parameter for controlling the temperature of the heating element . A method according to any one of claims 1 to 7, wherein the step of analyzing the monitored parameters indicative of aerosol generation includes the steps of calculating a first characteristic of the monitored parameters indicative of aerosol generation, and analyzing the first characteristic to determine the start and end of a puff. The method of claim 8, wherein the step of analyzing the monitored parameter indicative of aerosol generation includes the steps of calculating a second characteristic of the monitored parameter indicative of aerosol generation, and analyzing both the first characteristic and the second characteristic to determine the start of the puff and the cessation of the puff. The method of claim 8 or claim 9, wherein the first characteristic is a first moving average value of the monitored parameter calculated over a first time window having a first time window duration. A method according to any one of claims 8 to 10, wherein the first characteristic is a first moving median of the monitored parameter indicative of aerosol generation calculated over a first time window having a first time window duration. 1. An aerosol generation device for generating an aerosol from an aerosol-forming substrate during a use session, the aerosol generation device comprising: a power supply for providing power to generate the aerosol; and a controller configured to monitor a user interaction parameter indicative of use of the aerosol generation device during the use session, and to use the user interaction parameter to control the temperature of a heating element during the use session;
An aerosol generating device, the device being configured to monitor parameters indicative of aerosol generation during operation of the aerosol generating device, analyze the monitored parameters to identify a user's puff defined by the start of the puff and the end of the puff, analyze the monitored parameters during the user's puff to calculate a puff volume, which is the volume of aerosol generated during the user's puff, and control the temperature of the heating element based on the calculated puff volume. The aerosol generating device according to claim 12, configured to carry out a method as defined in any one of claims 1 to 11. 1. An aerosol generation device for generating an aerosol from an aerosol-forming substrate during a use session, said aerosol generation device comprising: a power supply for providing power to generate said aerosol; and a controller; said aerosol generation device comprising a computer-readable medium containing instructions for performing a method of monitoring a user interaction parameter indicative of use of said aerosol generation device during said use session; and using said user interaction parameter as a parameter for controlling the temperature of a heating element during said use session;
An aerosol generating device, the device being configured to monitor parameters indicative of aerosol generation during operation of the aerosol generating device, analyze the monitored parameters to identify a user's puff defined by the start of the puff and the end of the puff, analyze the monitored parameters during the user's puff to calculate a puff volume, which is the volume of aerosol generated during the user's puff, and control the temperature of the heating element based on the calculated puff volume. An aerosol generating device for generating an aerosol from an aerosol-forming substrate during a session of use, the aerosol generating device comprising: a power supply for providing power to generate the aerosol; and a controller; and a computer-readable medium containing instructions for carrying out the method of any one of claims 1 to 11.