Method of operating an aerosol-generating device for generating an aerosol from an aerosol-forming substrate and aerosol-generating device operable with such a method

Abstract

A method of operating an aerosol-generating device for generating an aerosol from an aerosol-forming substrate, and an aerosol-generating device or system for generating an aerosol according to such method, the method comprising the steps of determining over a predefined determination window during a user session a value of an operational parameter associated with the generation of the aerosol, comparing the determined value with one or more reference values; and determining, based on the comparison of the determined value with the one or more reference values, an adjustive number of user puffs for the user session and / or an adjustive operating time for the user session.

Description

[0001] Method of OPERATING AN AEROSOL-GENERATING DEVICE FOR GENERATING AN AEROSOL FROM AN AEROSOL-FORMING SUBSTRATE AND AEROSOLGENERATING device OPERABLE WITH SUCH A METHOD

[0002] The present disclosure relates to a method of operating an aerosol-generating device or system for generating an aerosol from an aerosol-forming substrate. The invention further relates to an aerosol-generating device or system for generating an aerosol from an aerosol-forming substrate, in particular according to such a method.

[0003] Aerosol-generating devices configured to generate an aerosol from an aerosol-forming substrate are generally known from the state of the art. For example, the aerosol may be generated by heating an aerosol-forming substrate that is capable of releasing volatile compounds when heated. As the released compounds cool down, they condense to form an aerosol that is inhalable by a user when puffing on the device.

[0004] Once a user session is started, the volatile compounds in the aerosol-forming substrate get depleted. As a consequence, the quality of the aerosol produced may deteriorate during the course of a user session, or the aerosol-forming substrate may partially or fully deplete during the user session. Therefore, the aerosol-generating device may be configured to limit the user session in order to prevent the generation of lower quality aerosol. In addition, limiting the user session may be used to approximate the experience of consuming a traditional cigarette.

[0005] In some aerosol-generating devices, the duration of a user session is determined purely by a finite operating time or by a fixed number of puffs that can be taken by a user. However, such limitations do not take into consideration the diversity of user behavior. For example, one user may take long or strong puffs, thus depleting the aerosol-forming substrate within the finite operating time of the user session time or within the predetermined number of puffs. Vice versa, another user or the same user under different conditions may take short or less-intensive puffs, so that at the end of the finite operating time or after the fixed number of puffs, there is still unconsumed substrate available. To mitigate this problem, it has been proposed to use the generated aerosol volume as a parameter for determining the duration of the user session. During the user session, the aerosol volume generated during a plurality of user puffs is determined until a maximum aerosol volume for the user session has been reached. However, this method has the disadvantage that the computation of the generated aerosol volume may be difficult to achieve, in particular when the environmental conditions, such as high humidity, low temperatures, atmospheric pressure, etc., differ from test and calibration conditions. As a result, the computation of the generated aerosol volume may be subject to an error margin.

[0006] Therefore, it would be desirable to have an aerosol-generating device or system with the advantages of known solutions, whilst mitigating their limitations. In particular, it would be desirable to have a method for operating an aerosol-generating device or system and an aerosolgenerating device or system operable with such a method that can more reliably determine the optimal duration of a user session in due consideration of the diversity of user behavior, in order to prevent the generation of lower quality aerosol. In addition, it would be desirable to optimize use of the available aerosol-forming substrate, for example to avoid discarding aerosol-generating articles that have only been partially consumed, thereby reducing waste and optimizing the consumption of the aerosol-forming substrate.

[0007] According to an aspect of the present invention, there is provided a method of operating an aerosol-generating device or system for generating an aerosol from an aerosol-forming substrate. The method comprises the steps of determining over a predefined determination window during a user session a value of an operational parameter associated with the generation of the aerosol, comparing the determined value with one or more reference values and determining, based on the comparison of the determined value with the one or more reference values, an adjustive number of user puffs for that user session and / or an adjustive operating time for that user session. Since the operational parameter is associated with the generation of the aerosol and hence with a user’s behavior, the method according to the present invention has the advantage that the comparison of the determined value of the operational parameter with the one or more reference values allows for taking into consideration a user’s behavior and extend the user session, either in terms of additional user puffs and / or additional operating time, or shorten the user session, either in terms of user puffs or operating time, according to the user’s behavior.

[0008] As used herein, the term “predefined determination window” refers to a predetermined measurement frame with a finite length, in particular a finite length in terms of time or number of user puffs. For example, the predefined determination window may correspond to a measurement time frame or a user puff frame during which the aerosol-forming substrate is at or above a predefined operational temperature. The operational temperature may be a temperature that allows the generation of aerosol, or may be a temperature slightly below the temperature necessary for aerosol generation, wherein the aerosol-forming substrate may be further heated to generate aerosol upon detection of a puff being taken by a user. In particular, such a predefined determination window, and hence the method and the device / system disclosed herein, may be particularly suited for a “heat-not-burn” aerosol-generation.

[0009] The term “aerosol-forming substrate” denotes, as used herein, a substrate formed from or comprising an aerosol-forming material that is capable of releasing volatile compounds upon heating in order to generate an aerosol. Preferably, the aerosol-forming substrate is intended to be heated rather than combusted in order to release the aerosol-forming volatile compounds. The aerosol-forming substrate may be a solid aerosol-forming substrate, a liquid aerosol-forming substrate, gel-like aerosol-forming substrate, or any combination thereof. For example, the aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds, which are released from the substrate upon heating. Alternatively or additionally, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol. The aerosol-forming substrate may also comprise other additives and ingredients, such as nicotine, flavorants or botanicals. The aerosol-forming substrate may also be a paste-like material, a sachet of porous material comprising aerosol-forming substrate, or, for example, loose tobacco mixed with a gelling agent or sticky agent, which could include a common aerosol former such as glycerin, and which is compressed or molded into a plug. For example, WO 2020 / 207733 A1 and WO 2022 / 248378 A1 disclose aerosol-forming substrates that are preferably tobacco-free and are herewith incorporated by reference in their entirety.

[0010] As used herein, the term “aerosol-generating device” describes an electrically operated device for interaction with an aerosol-forming substrate in order to generate an aerosol by heating the aerosol-forming substrate, resistively and / or inductively via at least one susceptor element, or by dielectric heating. Preferably, the aerosol-generating device is a puffing device for generating an aerosol that is directly inhalable by a user through the user's mouth. In particular, the aerosolgenerating device is a hand-held aerosol-generating device.

[0011] According to the present disclosure, the term “adjustive number of user puffs” refers to a number of user puffs determined according to an aspect of the method of the present invention and used to either extend the length of the user session, by allowing the user to take a determined number of adjustive additional user puffs in addition to a predefined number of (planned) user puffs or a predefined (planned) operating time, or to shorten the length of the user session by removing the determined number of adjustive user puffs from a predefined planned number of user puffs. Likewise, the term “adjustive operating time” refers to a time value determined according to an aspect of the method of the present invention and used to either extend the length of the user session, by allowing the user to continue the user session for an adjustive additional operating time in addition to a predefined number of (planned) user puffs or a predefined (planned) operating time, or to shorten the length of the user session by removing the determined adjustive operating time from a predefined planned operating time.

[0012] As will be explained later in more detail, the operational parameter may be associated with the volume of aerosol generated during the user session.

[0013] Therefore, the method according to the present invention allows, for example, to grant an adjustive additional number of user puffs during a user session in the case the user is taking mild and / or short puffs and the method determines that the aerosol-forming substrate is not depleted and the adjustive additional number of user puffs can be granted for that user session. The method according to the present invention also allows, for example, to shorten the user session in the case the user is taking strong or very long puffs and the method determines that the aerosolforming substrate may be depleted within a predefined planned number of user puffs and / or a predefined planned operating time.

[0014] As used herein, “volume of aerosol” or “aerosol volume” refer to a value indicative of the amount of aerosol generated during a user puff, for example a volume of air drawn during that user puff, a volume of air including aerosol drawn during that user puff, a quantity of air combined with aerosol exiting, in a flow direction of the airflow through the device, a downstream side of the aerosol-forming substrate during that user puff, or an amount of aerosol-forming substrate that has been volatilized during that user puff.

[0015] In general, the predefined determination window may correspond to a predefined number of user puffs, the predefined number of user puffs being equal to or smaller than a predefined planned number of user puffs for the user session. That is, the predefined determination window may in particular correspond to a predefined planned number of user puffs for the user session. For example, the predefined number of planned user puffs for the user session may correspond to the average number of puffs inhaled by a user when smoking a traditional cigarette and can be thereby used to approximate the experience of consuming a traditional cigarette.

[0016] Alternatively, the predefined determination window may correspond to a predefined number of user puffs that is smaller than the predefined planned number of user puffs for the user session. For example, a number N of user puffs may be planned for the user session, with the predefined determination window corresponding to M user puffs of the user session, with M being smaller than N (M < N). Therefore, the value of the operational parameter is determined over the predefined determination window of M user puffs, is compared with the one or more reference values and an adjustive number of user puffs for that user session and / or an adjustive operating time for that user session is determined based on the comparison. For example, once the predefined planned number N of user puffs have been drawn, the user session may be continued by adding the previously determined adjustive number of user puffs for the user session and / or an adjustive operating time for the user session to the predefined planned number of user puffs for the user session or to the predefined number of user puffs or to the predefined planned operating time for the user session or to the predefined operating time.

[0017] Alternatively, the determined adjustive number of user puffs for the user session may be subtracted from the predefined planned number of user puffs for the user session.

[0018] Preferably, as a non-limiting example, a difference between the predefined planned number of user puffs for the user session and the predefined number of user puffs is at most four (4) user puffs, in particular three (3) user puffs, preferably two (2) user puffs. Hence, a difference between the predefined planned number N of user puffs for the user session and the predefined determination window corresponding to M user puffs is at most four (4) user puffs, in particular three (3) user puffs, preferably two (2) user puffs. This has the advantage that the determination of an adjustive number of user puffs for the user session and / or adjustive operating time for the user session may be performed before reaching the predefined planned number of user puffs for the user session and the user session may already be extended or shortened depending on the user’s behavior without an idle time for determining the adjustive number of user puffs or adjustive operating time.

[0019] In this regard, as a non-limiting example, the predefined number of user puffs may be in a range between 2 and 14, in particular between 7 and 13, more particularly between 9 and 12, for instance 12.

[0020] As a non-limiting example, the predefined planned number of user puffs may be at least two (2), in particular at least three (3), more particularly at least four (4), preferably at least six (6), more preferably at least seven (7), even more preferably at least eight (8), particularly preferred at least nine (9), more particularly preferred at least ten (10), even more particularly preferred at least eleven (11), specifically twelve (12), more specifically thirteen (13) and even more specifically fourteen (14). In some preferred cases, the predefined planned number of user puffs may be even at least fifteen (15), sixteen (16), seventeen (17), eighteen (18), nineteen (19), or twenty (20).

[0021] Alternatively, as a non-limiting example, the predefined planned number of user puffs may be 2, in particular 3, more particularly 4, even more particularly 5, preferably 6, more preferably 7, even more preferably 8, particularly preferred 9, more particularly preferred 10, even more particularly preferred 11 , specifically 12, more specifically 13 and even more specifically 14. In some preferred cases, the predefined planned number of user puffs granted may be 15, 16, 17, 18, 19 or 20.

[0022] As a non-limiting example, the predefined planned number of user puffs may also be in a range between two (2) and twenty (20), in particular between five (5) and eighteen (18), more particularly between ten (10) and sixteen (16), preferably between twelve (12) and fifteen (15), more preferably between thirteen (13) and fourteen (14), for instance fourteen (14). The predefined planned number of user puffs respectively the range, as disclosed above, may be chosen such as to approximate the experience of consuming a traditional cigarette.

[0023] According to another preferred implementation of the method, the predefined determination window may correspond to a predefined operating time, the predefined operating time being equal to or shorter than a predefined planned operating time for the user session. That is, the predefined determination window may in particular correspond to a predefined planned operating time for the user session. For example, the predefined planned operating time for the user session may correspond to the average time a traditional cigarette is normally smoked and can be thereby used to approximate the experience of consuming a traditional cigarette. Alternatively, the predefined determination window may correspond to a predefined operating time. According to this preferred implementation, the predefined operating time, hence the predefined determination window, is shorter than the predefined planned operating time for the user session. For example, an operating time of X seconds may be planned for the user session, with the predefined determination window corresponding to Y seconds of operating time, with Y being shorter / smaller than X (Y < X). Therefore, the value of the operational parameter is determined over the predefined determination window of Y seconds, is compared with the one or more reference values and an adjustive number of user puffs for the user session and / or an adjustive operating time for the user session is determined based on the comparison. For example, once the predefined minimum operating time X has elapsed, the user session may be continued by adding the previously determined adjustive number of user puffs for the user session and / or the adjustive operating time for the user session to the predefined planned number of user puffs for the user session or to the predefined number of user puff or to the predefined planned operating time for the user session or to the predefined operating time.

[0024] Alternatively, the determined adjustive operating time for the user session may be subtracted from the predefined planned operating time for the user session.

[0025] Preferably, as a non-limiting example, a difference between the predefined planned operating time for the user session and the predefined operating time is at most 240 seconds, in particular 180 seconds, preferably 120 seconds. Hence, a difference between the predefined planned operating time of X seconds for the user session and the predefined determination window (corresponding to Y seconds of operating time) is at most 240 seconds, in particular 180 seconds, preferably 120 seconds. This has the advantage that the determination of an adjustive number of user puffs for the user session and / or adjustive operating time for the user session may be performed before reaching the predefined planned operating time for the user session and the user session may already be extended or shortened depending on the user’s behavior without an idle time for determining the adjustive number of user puffs or adjustive operating time.

[0026] The adjustive operating time for the user session may be in addition to the predefined planned operating time for the user session or in addition to the predefined operating time or in addition to a predefined number of user puffs or a predefined planned number of user puffs for the user session.

[0027] The predefined determination window may, in a preferred implementation of the method, correspond to a predefined number of user puffs, in particular a predefined minimum number of user puffs granted for each user session, and a predefined operating time, in particular a predefined minimum operating time granted for each user session. That means that the predefined determination window is associated to both a predefined number of user puffs and a predefined operating time, wherein the value of the operational parameter is determined over the predefined number of user puffs or the predefined operating time, whichever happens earlier. For example, the predefined determination window may correspond to a predefined number N of user puffs and a predefined operating time T granted for the user session. If the number N of granted user puffs is achieved before the operating time T has elapsed, the value of the operational parameter is determined over the predefined determination window corresponding to the number N of predefined user puffs. Vice-versa, if the operating time T has elapsed before achieving the predefined number N, the value of the operational parameter is determined over the predefined determination window corresponding to the predefined operating time T.

[0028] As already cited above, the operational parameter is associated with the generation of the aerosol. Therefore, different approaches exist for measuring the aerosol generation.

[0029] Preferably, the operational parameter is representative of an energy provided to generate the aerosol during the predefined determination window. This may be in particular an energy associated with power supplied by a power supply of the aerosol-generating device to generate the aerosol. Current, voltage or both current and voltage supplied by the power supply to generate the aerosol may be used for determining the power supplied. In aerosol-generating devices, the aerosol-forming substrate is heated by a heater to generate the aerosol. The heater may be a resistive heater, a convection heater, an induction heater, a dielectric heater, a combination of these heater types or any other type of heater. The induction heater may comprise an induction coil and at least one inductively heatable susceptor element. To generate the aerosol, the aerosolgenerating substrate is heated by the heater to a predefined operating temperature. During a user puff, the heater cools and a greater amount of power is necessary to maintain the heater to the predefined operating temperature. Therefore, by monitoring an operational parameter representative of an energy associated with power supplied by a power supply to generate the aerosol, in particular a peak or bump in the power supplied by the power supply, a value representative of the generated aerosol during the predefined determination window may be determined, and, in addition, also a user puff may simultaneously be detected. For example, for one user puff, the energy provided to generate the aerosol may be determined by integrating the power P supplied by the power supply during the user puff (tstart, tend) minus a factor A that takes into consideration the energy that would be anyway provided to the aerosol-generating device, in particular to keep the heater at the predefined operating temperature, hence the energy that would be provided even without a user puff according to the following equation: Therefore, the value of the operational parameter may be determined as the sum of the energy provided for each user puff of a plurality of N user puffs during the predefined determination window according to the following equation:

[0030] N

[0031] E ~ ' Epuff i i = 1

[0032] Alternatively, the operational parameter may be an arithmetic mean energy per user puff provided to generate the aerosol during the predefined determination window. According to this preferred implementation of the method, the operational parameter is representative of an energy provided to generate the aerosol during the predefined determination window, in particular an energy associated with power supplied by a power supply of the aerosol-generating device to generate the aerosol, divided by the number N of user puffs that have been provided during the predefined determination window according to the following equation:

[0033] Alternatively, the energy provided to generate the aerosol may be determined by integrating the power P supplied by the power supply during the predefined determination window (tstart PDW, tend PDW) minus a factor A that takes into consideration the energy that would be anyway provided to the aerosol-generating device, in particular to keep the heater at the predefined operating temperature, hence the energy that would be provided even without a user puff according to the following equation:

[0034] Therefore, the value of the operational parameter may be determined without the need of determining the start time and stop time (tstart, tend) of each user puff, which may be prone to errors. Therefore, a computational error can be reduced and the value of the operational parameter can be reliably determined, in particular across a variety of environmental conditions.

[0035] The operational parameter may be also determined as an arithmetic mean energy per user puff provided to generate the aerosol during the predefined determination window according to the following equation:

[0036] _ E

[0037] E =N

[0038] Alternatively, the operational parameter is a volume of aerosol generated during the predefined determination window. The volume of generated aerosol may be preferably determined by simple correlation of the energy provided to generate the aerosol during the predefined determination window with the generated aerosol volume, as known from the state of the art. Of course, the volume may be also determined by means of a flow sensor, but such a sensor could increase the complexity of the aerosol-generating device and may clog with aerosol particles, dirt, etc., potentially requiring special designs of such sensing mechanism. By a simple correlation, the generated aerosol volume may be determined with existing components of the aerosol-generating device, in particular by means of a controller already present in the aerosolgenerating device.

[0039] Likewise, as for the arithmetic mean energy per user puff, the operational parameter may be preferably an arithmetic mean volume of aerosol generated per user puff, that means a sum of the aerosol volume generated during each user puff of a plurality of N user puffs during the predefined determination window, divided by the number N of user puffs or a volume of aerosol generated during the predefined determination window divided by the number N of user puffs.

[0040] The determination of the value of the operational parameter may be performed continuously during the predefined determination window by updating a sum of the value of the operational parameter after every user puff, or may be determined at the end of the predefined determination window.

[0041] In order to determine the adjustive number of user puffs for the user session and / or the adjustive operating time for the user session to account for a user’s behavior, the method may comprise, in the step of comparing the determined value with the one or more reference values, a comparison of the determined value with a set of reference ranges defined by the one or more reference values and the allocation of the determined value to one of the reference ranges, wherein each reference range is associated with an adjustive number of user puffs for the user session and / or with an adjustive operating time for the user session. For example, the set of reference ranges may comprise two reference ranges, and the determined value is compared with the reference ranges and allocated to the reference range comprising the determined value. Then, the adjustive number of user puffs for the user session and / or the adjustive operating time for the user session is determined.

[0042] The set of reference ranges may comprise, as cited above, at least two reference ranges, but may in particular comprise three reference ranges, preferably four reference ranges, even more preferred five reference ranges.

[0043] Preferably, as a non-limiting example, a first reference range may be associated with six (6) adjustive user puffs, a second reference range may be associated with four (4) adjustive user puffs, a third reference range may be associated with two (2) adjustive user puffs and a fourth reference range may be associated with zero adjustive user puffs. Preferably, the adjustive user puffs are adjustive additional user puffs.

[0044] Likewise, in the case where an adjustive operating time is determined, as a non-limiting example, a first reference range may be associated with 60 seconds of adjustive operating time, a second reference range may be associated with 40 seconds of adjustive operating time, a third reference range may be associated with 20 seconds of adjustive operating time and a fourth reference range may be associated with zero adjustive operating time. Preferably, the adjustive operating time is an adjustive additional operating time.

[0045] As already mentioned, the determined value may be an arithmetic mean volume of aerosol generated per user puff during the predefined determination window: In such a case, as a nonlimiting example, a first reference range may preferably extend from above 20 milliliters up to 30 milliliters and may be associated with six adjustive user puffs, a second reference range may extend from above 30 milliliters and up to 40 milliliters and may be associated with four adjustive user puffs, a third reference range may extend from above 40 milliliters up to 50 milliliters and may be associated with two adjustive user puffs, and a fourth reference range may start above 50 milliliters and may be associated with zero adjustive user puffs. For example, if it is determined that the arithmetic mean volume of aerosol generated per user puff during the predefined determination window is 45 milliliters, two adjustive user puffs may be determined for that user session. Preferably, the adjustive user puffs are adjustive additional user puffs.

[0046] Preferably, only two reference ranges may be provided. The first reference range may be associated with adjustive user puffs, in particular six adjustive user puffs, and the second reference range may be associated with zero adjustive user puffs.

[0047] Likewise, the first reference range may be associated with adjustive operating time, in particular 360 seconds of adjustive operating time, and the second reference range may be associated with zero adjustive operating time.

[0048] Although in the above description different possibilities of reference ranges have been discussed, it should be pointed out that providing a reference range associated to zero adjustive user puffs or zero adjustive operating time is not necessary. For example, the reference ranges and the predetermined determination window may be selected such that adjustive user puffs and / or adjustive operating time is always determined.

[0049] The method may further comprise the step of terminating the user session after the predefined planned number of user puffs for the user session plus the adjustive number of user puffs determined for the user session, or after the predefined number of user puffs plus the adjustive number of user puffs determined for the user session, or after the predefined planned operating time for the user session plus the adjustive operating time determined for the user session, or after the predefined operating time plus the adjustive operating time determined for the user session. The user session may be also terminated after the predefined planned number of user puffs for the user session minus the adjustive number of user puffs determined for the user session or after the predefined planned operating time for the user session minus the adjustive operating time determined for the user session. The method may also comprise determining both an adjustive number of user puffs for the user session and an adjustive operating time for the user session. For example, the user session may be extended until the adjustive number of user puffs has been provided or the adjustive operating time has elapsed, whichever happens earlier, in the case where the adjustive number of user puffs are adjustive additional user puffs and the adjustive operating time is an adjustive additional operating time.

[0050] The start of the user session and in particular also of the predefined determination window may be preferably determined by identifying a first user puff.

[0051] In another preferred implementation of the method, the start of the user session may be determined by identifying the insertion of an aerosol-generating article comprising the aerosolforming substrate into a receiving cavity of the aerosol-generating device. This has the advantage that the user session may be automatically started without the need for a user to perform further actions. For example, at least one of a capacitive sensor, an inductive sensor, an optical sensor, a microswitch and combinations thereof may be used to identify the insertion of the aerosolgenerating article.

[0052] For example, determining the start of the user session may trigger the activation of a heater for heating the aerosol-forming substrate to the predefined operating temperature. In addition, after determining the start of the user session, the method may comprise the step of determining the start of the predefined determination window after a predefined period of time or upon determining that the aerosol-forming substrate has reached a predefined operating temperature. Alternatively, or additionally, the start of the predefined determination window may be also determined by identifying a first user puff.

[0053] The insertion of the aerosol-generating article may also trigger a recognition step, to recognize the type of aerosol-generating article that has been inserted into the receiving cavity and hence the type of the aerosol-forming substrate present in the aerosol-generating article. The type of aerosol-forming substrate present in the aerosol-generating article may be associated with a specific operational parameter to be determined and / or with at least one specific reference value for the aerosol-forming substrate that is / are then used in the method when the specific aerosolgenerating article has been identified. For example, a first type of aerosol-generating article may be associated with a first set of one or more reference values, and a second type of aerosolgenerating article may be associated with a second set of one or more reference values. Upon recognition of the type of aerosol-generating article that has been inserted into the receiving cavity (first type or second type), the associated set of one or more reference values is retrieved and used in the comparation step of the method.

[0054] The predefined determination window may, in a preferred, non-limiting implementation of the method, correspond to a predefined number of twelve (12) user puffs. In addition, the user session is associated to a predefined maximum operating time, for example 360 seconds. A predefined number of planned user puffs for the user session can correspond to fourteen (14) user puffs, granted by default. The value of the operational parameter is determined over the predefined determination window of twelve (12) user puffs or 360 seconds of maximum operating time, whichever happens earlier. Then, the determined value of the operational parameter is compared with a reference value. If the determined value of the operational parameter is above the reference value, then an adjustive number of zero (0) user puffs is determined for the user session, that means no additional puffs are granted, and the user session is continued until the predefined planned number of fourteen (14) user puffs has been taken, or the predefined maximum operating time of 360 seconds has elapsed, whichever happens earlier. It the determined value of the operational parameter is below or equal to the reference value, then an adjustive additional number of four (4) user puffs for the user session in addition to the predefined planned number of fourteen (14) user puffs for the user session is determined, and the user session is extended accordingly to a total of eighteen (18) user puffs (of which twelve (12) have been already taken). The user session is the continued until the eighteenth user puff has been taken or the predefined maximum operating time of 360 seconds has elapsed, whichever happens earlier.

[0055] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate capable of releasing volatile compounds when heated which can form an aerosol. Preferably, the aerosol-generating article is a heated aerosol-generating article. That is, an aerosol-generating article which comprises at least one aerosol-forming substrate that is intended to be heated rather than combusted. The aerosol-generating article may be a consumable, in particular a consumable to be discarded after a single use. For example, the article may be a cartridge including a liquid aerosol-forming substrate to be heated. As another example, the article may be a rod-shaped article, in particular a tobacco article, resembling conventional cigarettes.

[0056] As used herein, the term “aerosol-generating system” refers to a system comprising at least one aerosol-generating device and at least one aerosol-generating article. The aerosolgenerating system may further comprise additional components, such as a companion device used for example, for storing the aerosol-generating device and (re-)charging a power supply of the aerosol-generating device.

[0057] According to another aspect of the present invention, there is provided an aerosolgenerating device for generating an aerosol from an aerosol-forming substrate. The aerosol generating device comprising a power supply for supplying power to generate the aerosol; and a controller configured to perform the method according to the present disclosure. Therefore, the above described method applies accordingly to the aerosol-generating device according to the present invention.

[0058] It has been already discussed above that a user puff may be determined by monitoring the operational parameter, in particular when the operational parameter is representative of an energy provided to generate the aerosol, but alternatively or additionally, the device may further comprise at least one puff sensor. The at least one puff sensor may be a pressure sensitive sensor, a temperature sensor, a flow measurement sensor or an optical sensor. The pressure sensitive sensor may be a microphone, a piezoelectrical sensor, a strain gauge sensor or a diaphragm sensor. The temperature sensor may be in particular a thermistor, a thermocouple, a pyrometer or a resistance thermometer. The flow measurement sensor may be in particular an electromagnetic flow sensor, an ultrasonic flow sensor, or an obstructive-type flow sensor with cantilevers. The optical sensor may be a diffraction sensor configured to detect a diffraction caused by the generated aerosol. The at least one puff sensor may be used to detect a user puff independently from the monitoring of the operational parameter, but is preferably used to validate, correct and / or reject a user puff determined via the monitoring of the operational parameter and vice-versa.

[0059] The aerosol-generating device may have different configurations for heating the aerosolforming substrate, such as a resistive heater, a convection heater, an induction heater, a dielectric heater, a combination of these heater types or any other type of heater. For example, the aerosolgenerating device may further comprise at least one resistive heater connected to the power supply for heating the aerosol-forming substrate.

[0060] Alternatively or additionally, the aerosol-generating device may further comprise at least one induction coil connected to the power supply for heating at least one susceptor element.

[0061] The at least one susceptor element may be part of the aerosol-generating device, hence the aerosol generating device may further comprise at least one susceptor inductively heatable by the induction coil.

[0062] The aerosol-generating device may further comprise, additionally or alternatively to the at least one susceptor, a receiving cavity for receiving an aerosol-generating article comprising the aerosol-forming substrate and at least one susceptor inductively heatable by the induction coil.

[0063] 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.

[0064] Example Ex1 : A method of operating an aerosol-generating device for generating an aerosol from an aerosol-forming substrate, the method comprising the steps of determining over a predefined determination window during a user session a value of an operational parameter associated with the generation of the aerosol; comparing the determined value with one or more reference values; and determining, based on the comparison of the determined value with the one or more reference values, an adjustive number of user puffs for the user session and / or an adjustive operating time for the user session.

[0065] Example Ex2: The method according to Example Ex1 , wherein the predefined determination window corresponds to a predefined number of user puffs, the predefined number of user puffs being equal to or smaller than a predefined planned number of user puffs for the user session.

[0066] Example Ex3: The method according to Example Ex2, wherein a difference between the predefined planned number of user puffs for the user session and the predefined number of user puffs is at most four user puffs, in particular three user puffs, preferably two user puffs.

[0067] Example Ex4: The method according to any one of Examples Ex2 or Ex3, wherein the adjustive number of user puffs for the user session is in addition to the predefined planned number of user puffs for the user session or in addition to the predefined number of user puffs or in addition to a predefined operating time, in particular a predefined planned operating time for the user session.

[0068] Example Ex5: The method according to any one of Examples Ex2 or Ex3, wherein the adjustive number of user puffs for the user session is subtracted from the predefined planned number of user puffs for the user session.

[0069] Example Ex6: The method according to any one of Examples Ex2 to Ex5, wherein the predefined number of user puffs is in a range between 2 and 14, in particular between 7 and 13, more particularly between 9 and 12, for instance 12.

[0070] Example Ex7: The method according to any one of Examples Ex2 to Ex6, wherein the predefined planned number of user puffs for the user session is at least two, in particular at least three, more particularly at least four, preferably at least six, more preferably at least seven, even more preferably at least eight, particularly preferred at least nine, more particularly preferred at least ten, even more particularly preferred at least eleven, specifically twelve, more specifically thirteen and even more specifically fourteen.

[0071] Example Ex8: The method according to any one of Examples Ex2 to Ex7, wherein the predefined planned number of user puffs for the user session is 2, in particular s, more particularly 4, even more particularly 5, preferably 6, more preferably 7, even more preferably 8, particularly preferred 9, more particularly preferred 10, even more particularly preferred 11 , specifically 12, more specifically 13 and even more specifically 14.

[0072] Example Ex9: The method according to any one Examples Ex2 to Ex8, wherein the predefined planned number of user puffs for the user session is in a range between 2 and 20, in particular between 5 and 18, more particularly between 10 and 16, preferably between 12 and 15, more preferably between 13 and 14, for instance 14. Example Ex10: The method according to Example Ex1 , wherein the predefined determination window corresponds to a predefined operating time, the predefined operating time being equal to or shorter than a predefined planned operating time for the user session.

[0073] Example Ex11 : The method according to Example Ex10, wherein a difference between the predefined planned operating time for the user session and the predefined operating time is at most 240 seconds, in particular 180 seconds, preferably 120 seconds.

[0074] Example Ex12: The method according to any one of Examples Ex10 or Ex11, wherein the adjustive operating time for the user session is in addition to the predefined planned operating time for the user session or in addition to the predefined operating time or in addition to a predefined number of user puffs, in particular a predefined planned number of user puffs for the user session.

[0075] Example Ex13: The method according to any one of Examples Ex10 or Ex11, wherein the adjustive operating time is subtracted from the predefined planned operating time for the user session.

[0076] Example Ex14: The method according to any one of the Examples Ex 1 to Ex13, wherein the operational parameter is representative of an energy provided to generate the aerosol, in particular an energy associated with power supplied by a power supply of the aerosol-generating device to generate the aerosol.

[0077] Example Ex15: The method according to any one of the preceding Examples Ex1 to Ex13, wherein the operational parameter is an arithmetic mean energy per user puff provided to generate the aerosol.

[0078] Example Ex16: The method according to any one of the preceding Examples Ex1 to Ex13, wherein the operational parameter is a volume of generated aerosol.

[0079] Example Ex17: The method according to any one of the preceding Examples Ex1 to Ex13, wherein the operational parameter is an arithmetic mean volume of aerosol generated per user puff.

[0080] Example Ex18: The method according to any one of the preceding Examples Ex1 to Ex17, wherein the step of comparing the determined value with the one or more reference values comprises comparing the determined value with a set of reference ranges defined by the one or more reference values and allocating the determined value to one of the reference ranges, wherein each reference range is associated with an adjustive number of user puffs for the user session and / or with an adjustive operating time for the user session.

[0081] Example Ex19: The method according to Example Ex18, wherein the set of reference ranges comprises at least two reference ranges, in particular three reference ranges, preferably four reference ranges, even more preferred five reference ranges. Example Ex20: The method according to Example Ex18 or Ex19 wherein a first reference range is associated with six adjustive user puffs, a second reference range is associated with four adjustive user puffs, a third reference range is associated with two adjustive user puffs and a fourth reference range is associated with zero adjustive user puffs.

[0082] Example Ex21 : The method according to Example Ex18 or Ex19, wherein a first reference range is associated with 60 seconds of adjustive operating time, a second reference range is associated with 40 seconds of adjustive operating time, a third reference range is associated with 20 seconds of adjustive operating time and a fourth reference range is associated with zero adjustive operating time.

[0083] Example Ex22: The method according to Example Ex18 or Ex19, wherein the determined value is an arithmetic mean volume of aerosol generated per user puff, and wherein a first reference range extends from above 20 milliliters up to 30 milliliters and is associated with six adjustive user puffs, a second reference range extends from above 30 milliliters and up to 40 milliliters and is associated with four adjustive user puffs, a third reference range extends from above 40 milliliters up to 50 milliliters and is associated with two adjustive user puffs and a fourth reference range starts above 50 milliliters and is associated with zero adjustive user puffs.

[0084] Example Ex23: The method according to Example Ex18 or Ex19, wherein a first reference range is associated with adjustive user puffs, in particular six user puffs, and a second reference range is associated with zero adjustive user puffs.

[0085] Example Ex24: The method according to Example Ex18 or Ex19, wherein a first reference range is associated with adjustive operating time, in particular 360 seconds of adjustive operating time and a second reference range is associated with zero adjustive operating time.

[0086] Example Ex25: The method according to any one of the preceding Examples Ex1 to Ex24, wherein the method further comprises terminating the user session after the predefined planned number of user puffs for the user session plus the adjustive number of user puffs determined for the user session; or after the predefined number of user puffs plus the adjustive number of user puffs determined for the user session; or after the predefined planned operating time for the user session plus the adjustive operating time determined for the user session; or after the predefined operating time plus the adjustive operating time determined for the user session; or after the predefined planned number of user puffs for the user session minus the adjustive number of user puffs determined for the user session, or after the predefined planned operating time for the user session minus the adjustive operating time determined for the user session.

[0087] Example Ex26: The method according to any one of the preceding Examples Ex1 to Ex25, wherein the method further comprises determining the start of the user session and preferably of the predefined determination window by identifying a first user puff. Example Ex27: The method according to any one of the preceding Examples Ex1 to Ex25, wherein the method further comprises determining the start of the user session by identifying the insertion of an aerosol-generating article comprising the aerosol-forming substrate into a receiving cavity of the aerosol-generating device.

[0088] Example Ex28: The method according to Example Ex27, wherein the method further comprises, after determining the start of the user session, the step of determining the start of the predefined determination window after a predefined period of time or upon determining that the aerosol-forming substrate has reached a predefined temperature.

[0089] Example Ex29: The method according to Example Ex27, wherein the method further comprises, after determining the start of the user session, the step of determining the start of the predefined determination window by identifying a first user puff.

[0090] Example Ex30: An aerosol-generating device or system for generating an aerosol from an aerosol-forming substrate, the aerosol generating device comprising a power supply for supplying power to generate the aerosol; and a controller configured to perform the method according to any one of the preceding Examples Ex1 to Ex29.

[0091] Example Ex31 : The aerosol-generating device according to Example Ex30, wherein the device further comprises at least one puff sensor, the at least one puff sensor being preferably a pressure sensitive sensor, in particular a microphone, or a temperature sensor, or a flow measurement sensor, or an optical sensor.

[0092] Example Ex32: The aerosol-generating device according to Example Ex30 or Ex31 , wherein the device further comprises at least one resistive heater connected to the power supply for heating the aerosol-forming substrate.

[0093] Example Ex33: The aerosol-generating device according to Example Ex30 or Ex31 , wherein the device further comprises at least one induction coil connected to the power supply for heating at least one susceptor element.

[0094] Example Ex34: The aerosol-generating device according to Example Ex33, wherein the device further comprises at least one susceptor inductively heatable by the induction coil.

[0095] Example Ex35: The aerosol-generating device according to Example Ex33, the device further comprising a receiving cavity for receiving an aerosol-generating article comprising the aerosol-forming substrate and at least one susceptor inductively heatable by the induction coil.

[0096] Examples will now be further described with reference to the figures in which:

[0097] Fig. 1 schematically shows an aerosol-generating article for use with an aerosol-generating device according to an aspect of the present invention;

[0098] Fig. 2 schematically shows an aerosol-generating device according to an aspect of the present invention; Fig. 3 schematically shows a flowchart of a method according to an aspect of the present invention;

[0099] Fig. 4 schematically shows a plot of the power supplied to generate an aerosol during a user session;

[0100] Fig. 5 schematically shows a table of reference ranges and associated adjustive additional number of user puffs according to an embodiment of the present invention;

[0101] Fig. 6 schematically shows a table of reference ranges and associated adjustive additional operating times according to another embodiment of the present invention;

[0102] Fig. 7 schematically shows a table of reference ranges ad associated adjustive additional number of user puffs and adjustive additional operating times according to yet another embodiment of the present invention,

[0103] Fig. 8 schematically shows a flowchart of a method according to an alternative of the present invention,

[0104] Fig. 9 schematically shows a plot of the power supplied to generate an aerosol during a user session according to the method of Fig. 8,

[0105] Fig. 10 schematically shows a table of reference ranges and associated adjustive additional number of user puffs used in the method according to the Figs. 8 and 9,

[0106] Fig. 11 schematically shows a table of reference ranges and associated adjustive additional number of user puffs and adjustive additional operating time used in the method according to the Figs. 8 and 9,

[0107] Fig. 12 schematically shows a flowchart of a method according to yet another alternative of the present invention, and

[0108] Fig. 13 schematically shows a table of reference ranges and associated adjustive number of user puffs used in the method according to Fig. 12.

[0109] Fig. 1 shows schematically an inductively heatable aerosol-generating article 10 comprising a susceptor element 1 (not to scale). The aerosol-generating article 10 is a substantially rodshaped consumable comprising five elements sequentially arranged in coaxial alignment: a distal front plug element 11 , a substrate element 12, a first tube element 13, a second tube element 14, and a filter element 15. The distal front plug element 11 is arranged at a distal end 16 of the aerosol-generating article 10 to cover and protect the distal front end of the substrate element 12, whereas the filter element 15 is arranged at a proximal end 17 of the aerosol-generating article 10. Both the distal front plug element 11 and the filter element 15 may be made of the same filter material. The filter element 15 preferably serves as a mouthpiece, preferably as part of a mouthpiece together with the second tube element 14. However, the present invention is not limited to inductive heating, and the aerosol-generating article 10 may be adapted to other types of heaters, such as a resistive heater, a convection heater, a dielectric heater, a combination of these heater types or any other type of heater.

[0110] In a non-limiting example, the filter element 15 may have a length of 10 millimeters to 14 millimeters, for example, 12 millimeters, whereas the distal front plug element 11 may have a length of 3 millimeters to 6 millimeters, for example, 5 millimeters. The substrate element 12 comprises an aerosol-forming substrate 18 to be heated as well as a susceptor element 1 that is configured and arranged to heat the aerosol forming substrate 18. For this, the susceptor element 1 is fully embedded in the aerosol forming substrate 18 such as to be in direct thermal contact with the aerosol forming substrate 18. The substrate element 12 may have a length of 10 millimeters to 14 millimeters, for example, 12 millimeters. Each one of the first and the second tube element 13, 14 is a hollow cellulose acetate tube having a central air passage 19, 20, wherein a cross-section of the central air passage 20 of the second tube element 14 is larger than a crosssection of the central air passage 19 of the first tube element 13. The first and second tube element 13, 14 may have a length of 6 millimeters to 10 millimeters, for example, 8 millimeters.

[0111] In use, volatile compounds released from the substrate element 12 upon heating are drawn through the first and second tube element 13, 14 and the filter element 15 towards the proximal end 17 of the aerosol-generating article 10 when a user is taking a user puff, cool down and condense to form an aerosol. Each of the aforementioned elements 11 , 12 ,13, 14, 15 may be substantially cylindrical. In particular, all elements 11 , 12 , 13, 14, 15 may have the same outer cross-sectional shape and dimensions.

[0112] In addition, the elements may be circumscribed by one or more outer wrappers such as to keep the elements together and to maintain the desired cross-sectional shape of the rod-shaped article. The distal front plug element 11 , the substrate element 12 and the first tube element 13 are circumscribed by a first wrapper 21 , whereas the second tube element 14 and the filter element 15 are circumscribed by a second wrapper 22. The second wrapper 22 also circumscribes at least a portion of the first tube element 13 (after being wrapped by the first wrapper 21) to connect the distal front plug element 11 , the substrate element 12 and the first tube element 13 being circumscribed by the first wrapper 21 to the second tube element 14 and the filter element 15. Preferably, the first and the second wrapper 21 , 22 are made of paper. In addition, the second wrapper 22 may comprise perforations around its circumference (not shown). The wrappers 21 , 22 may further comprise adhesive that adheres the overlapped free ends of the wrappers to each other.

[0113] As shown in Fig. 2, the aerosol-generating article 10 according to Fig. 1 is exemplarily configured for use with an inductively heating aerosol-generating device 23. Together, the aerosol-generating device 23 and the aerosol-generating article 10 form an aerosol-generating system 24. The aerosol-generating device 23 comprises a cylindrical receiving cavity 25 defined within a proximal portion 26 of the aerosol-generating device 23 for receiving a least a distal portion of the aerosol-generating article 10 therein. The aerosol-generating device 23 further comprises an inductive heating arrangement including an induction coil 27 for generating an alternating, in particular high-frequency magnetic field within the cylindrical receiving cavity 25. The induction coil 27 is a helical coil circumferentially surrounding the cylindrical receiving cavity 25. The induction coil 27 is arranged such that the susceptor element 1 of the aerosol-generating article 10 is exposed to a magnetic field upon inserting the aerosol-generating article 10 into the cylindrical receiving cavity 25 of the aerosol-generating device 23. Thus, when activating the inductive heating arrangement, the susceptor element 1 heats up due to eddy currents and / or hysteresis losses that are induced by the alternating magnetic field, depending on the magnetic and electric properties of the susceptor materials of the susceptor element 1. The susceptor element 1 is heated until reaching a predefined operating temperature sufficient to vaporize the aerosol-forming substrate 18 surrounding the susceptor element 1 within the aerosol generating article 10. Within a distal portion 28, the aerosol-generating device 23 further comprises a DC power supply 29 and a controller 30 (only schematically illustrated in Fig. 2) for powering and controlling the heating process. Apart from the induction coil 27, the inductive heating arrangement preferably is at least partially integral part of the controller 30. A puff sensor 31 connected (schematically represented by the dashed line) to the controller 30 may be optionally arranged within the receiving cavity 25 for detecting a user puff. The puff sensor 31 may be a temperature sensor or a pressure sensitive sensor, for example a microphone.

[0114] A flowchart of method according to the present disclosure for operating an aerosolgenerating device, for example the aerosol-generating device 23 of Fig. 2 is shown schematically in Fig. 3, while Fig. 4 schematically shows a plot of the power supplied by the power supply 29 to the induction coil 27 over time during a user session 2. The method will be described in the following with references to the aerosol-generating device 23, but it should be appreciated that the method according to the present disclosure may be implemented in other aerosol-generating devices, for example aerosol-generating devices comprising a resistive heating arrangement or aerosol-generating devices comprising an inductive heating arrangement with an induction coil 27 and at least one susceptor element, the susceptor element being part of the aerosol-generating device, or aerosol-generating devices with dielectric heating arrangements, convective heater arrangements, or a combination of these heating arrangements or any types of heater arrangements.

[0115] As shown in Fig. 3, in a first step 100, during the user session 2, a value of an operational parameter 3 is determined by the controller 30. The operational parameter 3 is chosen such as to be associated with the generation of the aerosol. For example, the operational parameter 3 may be representative of the energy provided by the power supply 29 to the induction coil 27 for heating the susceptor element 1 , volatilize the aerosol-forming substrate 18 and therefore generate the aerosol, and may be determined by monitoring a current and / or a voltage supplied by the power supply 29 to the induction coil 27. The aerosol-generating device 23 may be configured to detect the insertion of the aerosol-generating article 10 comprising the susceptor element 1 into the receiving cavity 25. Detection of the insertion of the aerosol-generating article may be performed, for example, by the controller 30 determining a change of an electrical property of the heating arrangement comprising the induction coil 27 and the susceptor element 1 , wherein the change of the electrical property of the heating arrangement is associated with the susceptor element 1 being inserted, at least partially, into the receiving cavity 25. Upon detection of the insertion of the aerosol-generating article 10 into the receiving cavity 25, the aerosol-generating device 23 starts heating the at least one susceptor element 1 and therefore the aerosol-forming substrate 18 of the aerosol-generating article 10 until a predefined operating temperature has been reached. Once the predefined operating temperature has been reached, the user session 2 is started at a time to.

[0116] At the time tstart upi, a user starts taking a first user puff UP1 which lasts until the time tend UPI . At the time tstartupi, the controller 30 also determines the start of the predefined determination window 4. In the example shown in Fig. 4, the predefined determination window corresponds to a predefined amount of an exemplary number of fourteen (14) user puffs that have been predefined as a planned number of user puffs for the user session 2. It should be pointed out that the start of the user session 2 may correspond with the start of the predefined determination window 4, but this is not mandatory. For example, both the user session 2 and the predefined determination window 4 may start at the time to, at the time tstartupi or any time between to and tstart UPI . Also, the predefined determination window 4 may be started before the first user puff UP1 is taken.

[0117] Cooling of the aerosol-forming substrate 18 and of the at least one susceptor element 1 caused by the airflow of the first user puff UP1 is sensed by the controller 30 and the power supplied by the power supply 29 is adapted accordingly to keep at least one susceptor element 1 at the predefined operating temperature, hence the peak (or bump) between tstart upi and tend upi in Fig. 4. The peak (or bump) between tstart UPI and tend UPI may be used by the controller 30 to determine the first user puff UP1. Alternatively, the above cited puff sensor 31 may be used. For example, the puff sensor 31 may be used to determine the start and the stop of the first user puff UP1 and the controller 30 may then use the power supplied by the power supply 29 to the induction coil 27 to validate, correct and / or reject the user puff determined by means of the puff sensor 31.

[0118] As the user session 2 continues, the user takes a plurality of user puffs, wherein in Fig. 4 only the first two user puffs UP1 and UP2 and the fourteenth and last user puff UP14 of the predefined determination window 4 are shown for simplicity’s sake. It should be noted that the intensity and / or duration of the user puffs may vary. As shown in Fig. 4, the first user puff UP1 has a greater length in terms of time and a greater intensity in terms of power delivered by the power supply 29 as compared to the second user puff UP2. The fourteenth user puff LIP14 has the same length in terms of time as the second user puff UP2, but a greater intensity. In other words, the first user puff UP1 , compared to the second user puff UP2, was a longer and intense user puff, while the fourteenth user puff LIP14, also compared to the second user puff UP2, had the same duration, but was more intense than the second user puff UP2. Is should also be appreciated that, in the example of Fig. 4, the power supplied by the power supply 29 between the user puffs is constant at a value PBL, which is the baseline power that is supplied to the induction coil 27 to keep the at least one susceptor element 1 at the predefined operating temperature. It should also be noted that such a trend of power delivered by the power supply 29 may also present if other types of heater, as explained above, are used.

[0119] Once the controller 30 determines that the fourteenth and last user puff LIP14 granted for the user session 2 has been drawn, the predefined determination window 4 is terminated at tend upi4 and a value of the operational parameter 3 associated with the generation of aerosol during the predefined determination window 4 is determined. In the example shown in Fig. 4, the power supplied by the power supply 29 during the predefined determination window 4 is used to determine the energy that has been used to generate the aerosol during each user puff. For example, for the first user puff UP1 , the energy that has been used to generate the aerosol of the first user puff EUPI corresponds to the integral calculus of the power signal during the first user puff UP1 (from tstart UPI to tend UPI) minus the energy A that is anyway provided to the induction coil 27 even without a user puff being taken according to:

[0120] In the example of Fig. 4, A is equal to PBL X (tend UPI - tstart UPI), but it should be clear that, since PBL may vary over time, this equation is merely exemplary. The energy EUPI provided to generate the aerosol during the first user puff UP1 is then correlated to the volume VUPI of aerosol generated during the first user puff UP1. The volume of aerosol generated for every user puff UP1, UP2 ... LIP14 is determined and the value of the operational parameter 3 is determined according to (VUPI + VUP2 + ...+ VUPi4) / 14 as an arithmetic mean volume of aerosol generated per user puff. The determination of the value of the operational parameter 3 may be performed at the end of the predefined determination window, but, for instance, may be also performed continuously by updating a sum of the volume of aerosol generated after every user puff. In a second step 110, the determined value of the operational parameter 3, hence the arithmetic mean volume of aerosol generated per user puff, is compared with one or more reference values RF.

[0121] In Fig. 5 a table showing in the left column four exemplary and non-limiting reference ranges defined by a plurality of reference values is depicted. The reference values are expressed in milliliters of generated aerosol per user puff. The first reference value RF1 is 20 milliliters, the second reference value RF2 is 30 milliliters, the third reference value RF3 is 40 milliliters and the fourth reference value RF4 is 50 milliliters. The first reference range extends from above the first reference value RF1 (20 milliliters) up to the second reference value RF2 (30 milliliters), the second reference range extends from above the second reference value RF2 (30 milliliters) up to the third reference value RF3 (40 milliliters), the third reference range extends from above the third reference value RF3 (40 milliliters) up to the fourth reference value RF4 (50 milliliters), and the fourth reference range starts above the fourth reference value RF4 (50 milliliters). The determined value of the operational parameter 3 is hence allocated to one of the reference ranges in the second step 110. For example, the value of the operational parameter 3 for the user session 2 may be determined in step 100 to be 33 milliliters. In this case the value of the operational parameter 3 is higher than the second reference value RF2 and lower than the third reference value RF3 and is therefore allocated to the second reference range of the table shown in Fig. 5.

[0122] In a third step 120, a number of adjustive additional user puffs 6 for the user session 2 and / or an adjustive additional operating time 7 for the user session 2 is determined, based on the comparison of step 110.

[0123] As depicted in Fig. 5, the second reference range is associated to four adjustive additional user puffs 6 for the user session 2, as shown in the right column of the table of Fig. 5. Therefore, in step 120, four adjustive additional user puffs 6 are determined for the user session 2, and the user session 2 is continued in a step 140 until the four adjustive additional user puffs 6 have been drawn. After the four adjustive additional user puffs 6 have been drawn, it is determined, in a step 130, for example by the controller 30, that the user session 2 is terminated. Once the user session 2 is terminated in step 130, the aerosol-generating device 23 may be automatically turned off.

[0124] As another example, the value of the operational parameter 3 may have been determined in step 100 to be 55 milliliters. In this case, the value of the operational parameter 3 is higher than the fourth reference value RF4 and is hence allocated to the fourth reference range of the table shown in Fig. 5, which is associated to zero adjustive additional user puffs 6 for the user session 2. In this case, since no adjustive additional user puffs 6 have been determined for the user session 2, the step 130 is performed and the user session 2 is terminated.

[0125] In Fig. 6, another example of a table showing in the left column the four exemplary reference ranges as in Fig. 5 is depicted, but the reference ranges are associated to an adjustive additional operating time 7 for the user session 2. The first reference range is associated with 60 seconds of adjustive additional operating time 7, and the second, third and fourth reference ranges are respectively associated with 40, 20 and zero seconds of adjustive additional operating time 7 for the user session 2.

[0126] If the value of the operational parameter 3 has been determined to be 33 milliliters in step 100, the method is performed as cited above until step 120, with the only difference that 40 seconds of adjustive additional operating time 7 are determined instead of four adjustive additional user puffs 6. Therefore, the user session 2 is continued in step 140 until the determined 40 seconds of adjustive additional operating time 7 have elapsed, and the user session 2 is then terminated in step 130. Analogously, if the value of the operational parameter 3 has been determined to be 55 milliliters, the value of the operational parameter 3 is allocated to the fourth reference range corresponding to zero seconds of adjustive additional operating time 7 in step 120, and the user session 2 is terminated in step 130.

[0127] Another example of a table showing in the left column the four exemplary reference ranges of Fig. 5 and Fig. 6 is shown in Fig. 7. However, the reference ranges are both associated with an adjustive additional number of user puffs 6 and an adjustive additional operating time 7 for the user session 2. Going back to the example where the value of the operational parameter 3 has been determined to be 33 milliliters in step 100, the method is performed as cited above until step 110, however, in step 120, both an adjustive additional number of user puffs 6 and an adjustive additional operating time 7 for the user session 2 are determined by allocating the determined value of the operational parameter 3 to the second reference range (4 adjustive additional user puffs and 40 seconds of adjustive additional operating time respectively). Therefore, in step 140, the user session 2 is continued until the determined number of adjustive additional user puffs 6 (for example but not limited to 4 additional user puffs) has been reached or the adjustive additional operating time (40 seconds of additional operating time) has elapsed, whichever happens earlier, and the user session is then terminated in step 130.

[0128] Although the above description of Figs. 3-7 refers to a predefined determination window 4 of fourteen user puffs granted for the user session 2 (predefined minimum number of user puffs granted for the user session), the predefined determination window 4 may correspond to a predefined number of user puffs being equal or smaller than the predefined planned number of user puffs for the user session. The predefined determination window 4 may also have a finite length in terms of a predefined planned operating time for the user session 2, or may correspond to a predefined operating time being equal to or shorter than the predefined planned operating time for the user session. The predefined determination window 4 may also have a finite length in terms of time and number of user puffs. In the latter case, the predefined determination window 4 may be determined as terminated when the predefined operating time, or the predefined planned operating time for the user session, or the predefined number of user puffs, or the predefined planned number of user puffs for the user session 2 has been reached, whichever happens earlier. Also, since the energy provided to generate the aerosol during the predefined determination window is correlated to the volume of generated aerosol during the predefined determination window, the value of the operational parameter 3 may not necessarily be the arithmetic mean volume of generated aerosol, but may be, for example, the energy provided to generate the aerosol, the arithmetic mean energy per user puff provided to generate the aerosol or the volume of generated aerosol, with respective reference values being provided accordingly.

[0129] Fig. 8 schematically shows a flowchart of a method according to an alternative of the present invention, and Fig. 9 a plot of the power supplied by the power supply 29 to the induction coil 27 over time during a user session 2 according to the alternative of the method of the present invention according to Fig. 8. The method substantially corresponds to the method described above with respect to the Figs. 3-7, but the predefined determination window 4, as shown in Fig. 9, corresponds to a predefined number of twelve user puffs UP1 to LIP12. However, for the user session 2, a predefined number of fourteen user puffs UP1 to LIP14 has been planned.

[0130] As shown in Fig. 8, the value of the operational parameter 3, in this example the total volume of aerosol generated, is determined according to step 100 over the predefined determination window 4 of twelve user puffs UP1 to LIP12.

[0131] In Fig. 10 a table showing in the left column two exemplary reference ranges defined by a reference value RF and in the right column associated adjustive additional number of user puffs 6 is depicted.

[0132] In step 110, the determined value of the operational parameter 3, is compared with the reference value RF.

[0133] The determined value of the operational parameter 3, hence the total volume of generated aerosol during the predefined determination window 4, may be lower than the reference value RF. In this case, in step 120, an adjustive additional number of six user puffs 6 for the user session 2 is determined. The user session 2 is then continued with the determined six adjustive additional user puffs in step 140. The six adjustive additional user puffs are however in addition to the predefined number of twelve user puffs UP1 to LIP12 (the predefined determination window 4). Hence, the user session 2 has a length of eighteen user puffs UP1 to LIP18, and is terminated after the eighteenth user puff LIP18 has been taken in step 130.

[0134] If, however, the determined value of the operational parameter 3 is equal to or higher than the reference value RF, a number of zero adjustive additional user puffs 6 is determined in step 120. Since a number of fourteen user puffs UP1 to UP 14 has been planned for the user session 2, the user session 2 is continued in step 150 with the remaining two user puffs UP13 and UP14, and is terminated in step 130. In Fig. 11 a table showing in the left column two exemplary reference ranges defined by a reference value RF, in the middle column associated adjustive additional number of user puffs 6 and in the right column associated adjustive additional operating time 7 is depicted.

[0135] In step 110, the determined value of the operational parameter 3, is compared with the reference value RF.

[0136] The determined value of the operational parameter 3, hence the total volume of generated aerosol during the predefined determination window 4, may be lower than the reference value RF. In this case, in step 120, an adjustive additional number of six user puffs 6 and an adjustive additional operating time 7 of 360 seconds for the user session 2 is determined. The user session 2 is then continued with the determined six adjustive additional user puffs 6 and the 360 seconds of adjustive additional operating time in step 140. The six adjustive additional user puffs 6 and the 360 seconds of adjustive additional operating time 7 are however in addition to the predefined number of twelve user puffs UP1 to LIP12 (the predefined determination window 4). Hence, the user session 2 is continued, after the twelfth user puff LIP12, either until the six adjustive additional user puffs 6 (LIP13 to LIP18) have been taken or until the 360 seconds of adjustive additional operating time 7 have elapsed, whichever happens earlier. The user session 2 is then terminated in step 130.

[0137] If, however, the determined value of the operational parameter 3 is equal to or higher than the reference value RF, an adjustive additional number of zero additional user puffs 6 and zero additional seconds of adjustive additional operating time 7 are determined in step 120. Since fourteen user puffs UP1 to UP 14 have been planned for the user session 2, the user session 2 is continued in step 150 with the remaining two user puffs UP13 and UP14, and is terminated in step 130.

[0138] Fig. 12 schematically shows a flowchart of a method according to an alternative of the present invention. Fig. 13 schematically shows in the left column two exemplary reference ranges defined by a reference value RF, and in the right column associated adjustive number of user puffs 6. The method substantially corresponds to the method described above, wherein the predefined determination window 4 corresponds to a predefined number of twelve user puffs UP1 to UP12. However, for the user session 2, a predefined number of fourteen user puffs UP1 to UP14 has been planned.

[0139] As shown in Fig. 12, the value of the operational parameter 3, in this example the total volume of aerosol generated, is determined according to step 100 over the predefined determination window 4 of twelve user puffs UP1 to UP12.

[0140] In step 110, the determined value of the operational parameter 3, is compared with the reference value RF. The determined value of the operational parameter 3, hence the total volume of generated aerosol during the predefined determination window 4, may be lower than the reference value RF. In this case, in step 120, an adjustive number of six user puffs 6 for the user session 2 is determined. The plus sign in brackets denotes that the adjustive number of six user puffs 6 are adjustive additional user puffs.

[0141] The user session 2 is then continued with the determined six (6) adjustive additional user puffs in step 140. The six adjustive additional user puffs are however in addition to the predefined number of twelve user puffs UP1 to LIP12 (the predefined determination window 4). Hence, the user session 2 has a length of eighteen user puffs UP1 to LIP18, and is terminated after the eighteenth user puff LIP18 has been taken in step 130.

[0142] If, however, the determined value of the operational parameter 3 is equal to or higher than the reference value RF, a number of one adjustive user puff 6 is determined in step 120. The minus sign in brackets denotes that the adjustive number of one user puff 6 is to be subtracted from the predefined planned number of user puffs for the user session.

[0143] As cited above, the predefined determination window 4 corresponds to twelve user puffs UP1 to LIP12, and fourteen user puffs UP1 to UP 14 have been planned for the user session 2. In step 120, however, one adjustive user puff 6 to be subtracted has been determined, and therefore, one adjustive user puff 6 is subtracted from the planned number of fourteen user puffs UP1 to UP14. As a consequence, the user session 2 has now a length of thirteen user puffs UP1 to UP13. The user session 2 is therefore continued in step 150 with the remaining user puff UP13, and is terminated in step 130.

[0144] With a method and an aerosol-generating device operated with such a method, as described above, it is therefore possible to reliably adapt the user session 2 to a behavior of the user by enabling the possibility to add adjustive additional user puffs and / or adjustive additional operating time or to remove adjustive user puffs and / or to remove adjustive operating time, depending on the amount of generated aerosol and the depletion of the aerosol-forming substrate 18 during the predefined determination window 4, while preventing the generation of low quality aerosol.

[0145] 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 ± 5% 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

CLAIMS1. A method of operating an aerosol-generating device for generating an aerosol from an aerosol-forming substrate, the method comprising the steps of: determining over a predefined determination window during a user session a value of an operational parameter associated with the generation of the aerosol; comparing the determined value with one or more reference values; and determining, based on the comparison of the determined value with the one or more reference values, an adjustive number of user puffs for the user session and / or an adjustive operating time for the user session.

2. The method according to claim 1 , wherein the predefined determination window corresponds to a predefined number of user puffs, the predefined number of user puffs being equal to or smaller than a predefined planned number of user puffs for the user session.

3. The method according to claim 2, wherein a difference between the predefined planned number of user puffs for the user session and the predefined number of user puffs is at most four user puffs, in particular three user puffs, preferably two user puffs.

4. The method according to any one of claims 2 or 3, wherein the adjustive number of user puffs for the user session is in addition to the predefined planned number of user puffs for the user session or in addition to the predefined number of user puffs or in addition to a predefined operating time, in particular a predefined planned operating time for the user session.

5. The method according to any one of claims 2 to 4, wherein the predefined number of user puffs is in a range between 2 and 14, in particular between 7 and 13, more particularly between 9 and 12, for instance 12.

6. The method according to any one of claims 2 to 5, wherein the predefined planned number of user puffs for the user session is at least two, in particular at least three, more particularly at least four, preferably at least six, more preferably at least seven, even more preferably at least eight, particularly preferred at least nine, more particularly preferred at least ten, even more particularly preferred at least eleven, specifically twelve, more specifically thirteen and even more specifically fourteen.

7. The method according to any one of claims 2 to 6, wherein the predefined planned number of user puffs for the user session is 2, in particular 3, more particularly 4, even more particularly 5, preferably 6, more preferably 7, even more preferably 8, particularly preferred 9, more particularly preferred 10, even more particularly preferred 11 , specifically 12, more specifically 13 and even more specifically 14.

8. The method according to any one claims 2 to 7, wherein the predefined planned number of user puffs for the user session is in a range between 2 and 20, in particular between 5 and 18, more particularly between 10 and 16, preferably between 12 and 15, more preferably between 13 and 14, for instance 14.

9. The method according to claim 1 , wherein the predefined determination window corresponds to a predefined operating time, the predefined operating time being equal to or shorter than a predefined planned operating time for the user session.

10. The method according to claim 9, wherein the adjustive operating time for the user session is in addition to the predefined planned operating time for the user session or in addition to the predefined operating time or in addition to a predefined number of user puffs, in particular a predefined planned number of user puffs for the user session.

11. The method according to any one of the preceding claims, wherein the operational parameter is representative of an energy provided to generate the aerosol, in particular an energy associated with power supplied by a power supply of the aerosol-generating device to generate the aerosol.

12. The method according to any one of the preceding claims 1 to 10, wherein the operational parameter is an arithmetic mean energy per user puff provided to generate the aerosol.

13. The method according to any one of the preceding claims 1 to 10, wherein the operational parameter is a volume of generated aerosol.

14. The method according to any of the preceding claims 1 to 10, wherein the operational parameter is an arithmetic mean volume of aerosol generated per user puff.

15. The method according to any one of the preceding claims, wherein the step of comparing the determined value with the one or more reference values comprises comparing the determined value with a set of reference ranges defined by the one or more reference values and allocating the determined value to one of the reference ranges, wherein eachreference range is associated with an adjustive number of user puffs for the user session and / or with an adjustive operating time for the user session.

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