Aerosol generator for reducing the high-temperature aerosol effect

Abstract

The present invention relates to an aerosol generating device comprising a cavity for receiving an aerosol-forming substrate, an electric heater arranged to heat the aerosol-forming substrate, such as to provide a user with an inhalable aerosol experience when the aerosol-forming substrate is received in the cavity, a rechargeable power source capable of providing at least a first experience and a second experience without an intermediate recharge between the first experience and the second experience, and a controller arranged to control the supply of power from the rechargeable power source to the electric heater. The controller is arranged to determine a rate of temperature rise of the electric heater during a first period of the first experience by determining the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience. The controller is further arranged to prevent power from being supplied to the heater in the second experience if the rate of temperature rise of the electric heater during the first period of the first experience falls below a predetermined speed threshold and the second experience is started before the expiration of a predetermined time interval from the first experience. The present invention relates to an aerosol generating system comprising the aerosol generating device. The present invention relates to a method of controlling the aerosol generating device and a computer program for executing the method.

Description

Technical Field

[0001] The present invention relates to an aerosol generating device and a corresponding method for reducing the high temperature aerosol effect. The present invention also relates to an aerosol generating system comprising an aerosol generating device.

Background Art

[0002] One type of aerosol generating system is an electrically operated aerosol generating system. Known hand-held electrically operated aerosol generating systems generally comprise an aerosol generating device comprising a battery, a control electronic circuit, and an electric heater for heating an aerosol generating article specially designed for use in the aerosol generating device. The aerosol generating article comprises an aerosol forming substrate. In some embodiments, the aerosol forming substrate is in the form of a plug such as a tobacco plug, and the electric heater incorporated within the aerosol generating device is inserted into the aerosol forming substrate when the smoking article is inserted into the aerosol generating device.

[0003] Typically, the aerosol generating device is configured to generate heat using the electric heater according to a predetermined heating profile. However, changes in the aerosol forming substrate can result in undesirable changes in the user experience. For example, in a high humidity environment, the aerosol forming substrate may exhibit a high water content. Since water is aerosolized at the typical operating temperature of the aerosol generating device, a high water content can result in an unnecessarily high aerosol temperature (high temperature aerosol effect) perceived by the user.

[0004] A high water content can also result in a lower rate of temperature rise at the start of the user experience. Therefore, this rate of temperature rise may be used to determine whether the aerosol forming substrate has a normal or high water content.

[0005] New generation aerosol generating articles may include an aerosol forming substrate that absorbs less humidity than the substrates used in conventional aerosol generating articles. Due to the modified aerosol forming substrate, the influence of the high temperature aerosol effect is reduced for these aerosol generating articles.

[0006] However, such aerosol generating articles can be used in an aerosol generating device that can provide two or more user experiences to the user without intermediate recharging of the on-board power supply. Recent experiments have shown that in such aerosol generating devices, aerosol generating articles with increased humidity have a reduced resistance to the high temperature aerosol effect during continuous experiences.

[0007] It would be desirable to provide an aerosol generating device that reduces or overcomes at least some of the disadvantages associated with well-known aerosol generating devices.

[0008] In particular, it would be desirable to provide an aerosol generating device that enables reduction of the high temperature aerosol effect in a multi-experience aerosol generating device.

[0009] It is further desirable to provide an aerosol generating device that enables selection of a particularly suitable heating profile for an aerosol generating device that provides a plurality of user experiences without the need for intermediate recharging.

[0010] To further improve the overall user experience, it would be desirable to provide an aerosol generating device and corresponding method that enable improved communication with the user.

[0011] According to an embodiment of the present invention, there is provided an aerosol generating device comprising a cavity for receiving an aerosol-forming substrate, and an electric heater disposed to heat the aerosol-forming substrate when the aerosol-forming substrate is received in the cavity, such as to provide a user with an inhalable aerosol experience. The aerosol generating device also comprises a rechargeable power source capable of providing at least a first experience and a second experience without performing an intermediate recharge between the first experience and the second experience, and a controller disposed to control the supply of power from the rechargeable power source to the electric heater.

[0012] The controller is arranged to determine the rate of temperature increase of the electric heater during a first period of the first experience by determining the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience.

[0013] The controller is further arranged to prevent power from being supplied to the heater in the second experience if the rate of temperature increase of the electric heater during the first period of the first experience is below a predetermined rate threshold and if the second experience is started before the expiration of a predetermined time interval from the first experience.

[0014] The determined rate of temperature increase may indicate the water content of the aerosol-forming substrate received in the cavity. A determined relatively low rate of temperature increase may indicate a relatively high water content. A determined relatively high rate of temperature increase may indicate a relatively low water content. In conventional aerosol generating devices using an aerosol-forming substrate having a high tobacco content, the generation of the high-temperature aerosol effect was closely related to the water content of the aerosol-forming substrate.

[0015] In contrast, in aerosol generating devices that enable multiple user experiences, it has been observed that other factors also play an important role in the formation and generation of the high-temperature aerosol effect. In particular, when an aerosol-forming substrate with a low tobacco content is used, the occurrence of the high-temperature aerosol effect is generally reduced. However, for aerosol-forming substrates with a high water content, it has been observed that the high-temperature aerosol effect occurs mainly during continuous user experiences, especially when a continuous user experience is performed immediately after a previous user experience.

[0016] Accordingly, the present invention aims to reduce the high-temperature aerosol effect by forcing a time delay between user experiences when an aerosol-forming substrate with a high water content is detected. For this purpose, in a first period of a first user experience, the rate of temperature rise of the electric heater is determined. If the determined rate is below a predetermined rate threshold, the aerosol-forming substrate is considered to have a high water content. The controller is configured to force a time delay during continuous user experiences when an aerosol-forming substrate with a high water content is used. Next, the continuous user experience may be started only after the expiration of a predetermined time interval from the previous experience.

[0017] The present invention is directed to an aerosol generating device that enables at least two consecutive user experiences without the need for intermediate recharging. The aerosol generating device may enable up to 20 or more consecutive user experiences without the need for intermediate recharging.

[0018] The present invention is particularly useful for aerosol devices that enable more than one user experience without intermediate recharging. Accordingly, the present invention is generally described with reference to a first experience and a second experience. However, the present invention is not limited to the first and second experiences, but may be generally useful for controlling any two consecutive user experiences.

[0019] Accordingly, it is of course that the terms "first experience" or "previous experience" are used synonymously to mean the first user experience among two consecutive user experiences.

[0020] Similarly, the terms "second experience" or "consecutive experience" are used synonymously to mean the second user experience among two consecutive user experiences.

[0021] The first period of the first experience is preferably long enough to ensure a measurable temperature rise of the electric heater over a wide range of water contents of the aerosol-forming substrate. The first period is preferably at least about 1 second, more preferably at least about 2 seconds, and even more preferably at least about 3 seconds.

[0022] The first period of the first experience is preferably short enough to minimize the time before the controller changes the power supply to the electric heater during the second period to provide the desired user experience. The first period is preferably less than about 15 seconds, more preferably less than about 14 seconds, even more preferably less than about 13 seconds, even more preferably less than about 12 seconds, even more preferably less than about 11 seconds, and even more preferably less than about 10 seconds.

[0023] The controller may be arranged to determine the rate of temperature rise of the electric heater by determining the time taken for a predetermined temperature rise of the electric heater to occur. The controller may be arranged to determine the rate of temperature rise of the electric heater during a portion of the first period. The controller may be arranged to determine the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period, and the determined time is the determined rate of temperature rise.

[0024] The first predetermined temperature preferably exceeds any expected ambient temperature. Advantageously, the first predetermined temperature that exceeds the ambient temperature may minimize or eliminate any change in the ambient temperature at a determined temperature rise rate of the electric heater. The first predetermined temperature is preferably at least about 50 degrees Celsius, preferably at least about 60 degrees Celsius, preferably at least about 70 degrees Celsius, preferably at least about 80 degrees Celsius, preferably at least about 90 degrees Celsius. The first predetermined temperature may be 100 degrees Celsius. The first predetermined temperature may be at least about 150 degrees Celsius. The first predetermined temperature may be at least about 200 degrees Celsius.

[0025] It is understood that the numerical values specified herein include values within a range around the specified values, based on variations resulting from manufacturing tolerances and the accuracy of measuring instruments.

[0026] The second predetermined temperature preferably falls below the target operating temperature of the electric heater during the second period. Advantageously, the second predetermined temperature that falls below the target operating temperature may facilitate the determination of the temperature rise rate of the electric heater before the controller needs to start adjusting the supply of power to the electric heater during the second period. The second predetermined temperature is preferably less than about 400 degrees Celsius, preferably less than about 320 degrees Celsius, preferably less than about 290 degrees Celsius, preferably less than about 280 degrees Celsius, preferably less than about 270 degrees Celsius, preferably less than about 260 degrees Celsius. The second predetermined temperature may be 250 degrees Celsius.

[0027] The controller is preferably arranged to supply power to the electric heater from the power source at a constant speed during a first period of the first experience. Advantageously, supplying power to the electric heater at a constant speed during the first period may facilitate an accurate determination of the rate of temperature rise of the electric heater during the first period. The controller may be arranged to supply power to the electric heater from the power source with any desired duty cycle during the first period. The controller may be arranged to supply power to the electric heater from the power source with a duty cycle of at least about 50 percent during the first period. The controller may be arranged to supply power to the electric heater from the power source with a duty cycle of at least about 85 percent during the first period. The controller may be arranged to supply power to the electric heater from the power source with a duty cycle of at least about 90 percent during the first period. The controller may be arranged to supply power to the electric heater from the power source with a duty cycle of at least about 95 percent during the first period.

[0028] The controller may be arranged to evaluate the rate of temperature rise of the heater element during the first period of the first experience at any point during use of the aerosol generator.

[0029] The controller may be arranged to evaluate the rate of temperature rise of the heater element of the first experience when the user starts a second experience. At this point, the controller may determine the temperature rise of the heater element of the first experience and, at the same time, determine the elapsed time since the first experience. If the controller determines that the determined rate of temperature rise is below a predetermined threshold and the elapsed time since the first experience is below a predetermined time interval, the activation of the electric heater for the second experience is prevented.

[0030] The predetermined time interval may be in the range of 100 to 300 seconds. The predetermined time interval may be in the range of 120 to 280 seconds. The predetermined time interval may be in the range of 150 to 200 seconds. The predetermined time interval may be about 180 seconds.

[0031] On the other hand, when the controller determines that the determined speed exceeds a predetermined threshold value, or the elapsed time after the first experience exceeds a predetermined time interval, the activation of the heater is enabled and the user can perform a second user experience.

[0032] Advantageously, the controller may be arranged to first determine the elapsed time between two consecutive user experiences. If the elapsed time exceeds a predetermined time interval, the second experience can be executed under any circumstances. Therefore, in this situation, it is no longer necessary to evaluate the rate of temperature rise of the heater element in the first experience. In this way, the complexity of the controller scheme can be reduced and the required controller operations are fewer.

[0033] However, the above procedure may be recognized as inconvenient because information that a further user experience is temporarily unavailable is delivered by the aerosol generator only after the user has already decided to start the next user experience. Therefore, it may be more convenient for the user to be notified in advance, preferably at the end of the first user experience, about the availability of the next user experience. In this way, the user can be notified about the availability or unavailability of the next user experience, for example, before the user can insert a new aerosol-generating article into the aerosol generator.

[0034] Therefore, the controller of the aerosol generator may be arranged to determine the rate of temperature rise of the electric heater at the end of the first experience. If the controller determines that the determined rate of temperature rise of the electric heater exceeds a predetermined threshold rate, there is no need to impose a time delay before the next user experience is delivered. The aerosol can indicate to the user by any suitable means that consecutive experiences are available.

[0035] If the controller determines that the determined speed is below a predetermined threshold, the activation of the electric heater for implementing the second experience is prevented, and the second user experience may be started only after the expiration of a predetermined time interval from the first experience.

[0036] To inform the user of the need to have a timeout before the next user experience can be started, the controller may be configured to warn the user via a suitable user interface. By informing the user of the required time delay before the next user experience can be started, the user can already adapt to the required waiting time. This can help enhance the usefulness of the aerosol generating device for the user.

[0037] The user interface may include means for indicating to the user the duration of the required timeout period. The user interface may include acoustic, visual, tactile, sensory, or any other suitable means.

[0038] The visual user interface means may include a suitable light source. Advantageously, a light source with low power consumption may be used. Such suitable light sources include light emitting diodes (LEDs), micro LEDs or organic LED (OLED) devices. These light sources may be operated in a blinking mode to attract the user's attention. For example, a red LED may be operated in a blinking mode throughout the timeout period to inform the user that the aerosol generating device is not yet ready for operation. When the timeout period has elapsed, the blinking of the LED may stop. This may notify the user that the aerosol generating device is ready for the next experience.

[0039] The controller may include a power storage element. The controller may be arranged to communicate with the power storage element. The controller may be arranged to write to and read from the power storage element parameters or other information related to the control of the aerosol generator. The controller may be arranged to store the increase rate of the electric heater determined in the last user experience. The controller may be arranged to store the last used heating profile in the power storage element. The power storage element may be a memory element.

[0040] The controller may be arranged to determine the initial temperature of the electric heater, and may further be arranged to prevent the supply of power to the electric heater if the initial temperature of the electric heater exceeds a predetermined temperature threshold. Usually, if the controller requires a forced timeout between two user experiences, the electric heater should have enough time to cool. In this situation, the electric heater is most likely to have an initial temperature well below the predetermined temperature threshold.

[0041] However, if the determined rate of temperature rise of the electric heater during the first experience exceeds a predetermined threshold rate and the controller does not require a time delay before the next user experience, the initial temperature of the electric heater may rise and may exceed the predetermined temperature threshold at the start of successive experiences. If the controller determines that the initial temperature of the electric heater exceeds the predetermined temperature threshold, the supply of power to the electric heater may be prevented. The controller may be configured to periodically monitor the temperature of the electric heater.

[0042] The controller may further be arranged to start the supply of power from the power source to the electric heater when the initial temperature of the electric heater drops below the predetermined temperature threshold.

[0043] The predetermined temperature threshold for the initial temperature of the electric heater can be from about 50 degrees Celsius to about 150 degrees Celsius, from about 60 degrees Celsius to about 120 degrees Celsius, or preferably from about 80 degrees Celsius to about 100 degrees Celsius. The predetermined temperature threshold for the initial temperature of the electric heater may be 80 degrees Celsius.

[0044] To facilitate determining the rate of temperature rise of the electric heater, it is preferable that the controller is arranged to determine the temperature of the electric heater. The electric heater comprises at least one resistive heating element, and it is preferable that the controller is arranged to determine the temperature of at least one resistive heating element based on the resistance of at least one resistive heating element. The controller may comprise a circuit arranged to measure the resistance of at least one resistive heating element. The controller may be arranged to determine the temperature of at least one resistive heating element by comparing the measured resistance with a calibration curve of resistance versus temperature.

[0045] The electric heater preferably comprises a plurality of resistive heating elements. The resistive heating elements are preferably electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of the desired power to the electric heater while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate the electric heater may facilitate reducing or minimizing the physical size of the power source.

[0046] The electric heater may comprise an electrically insulated substrate, and at least one resistive heating element is provided on the electrically insulated substrate.

[0047] The electrically insulated substrate is preferably stable at the operating temperature of the electric heater. The electrically insulated substrate is preferably stable at a temperature of up to about 400 degrees Celsius, more preferably stable at about 500 degrees Celsius, more preferably stable at about 600 degrees Celsius, more preferably stable at about 700 degrees Celsius, and more preferably stable at about 800 degrees Celsius. The operating temperature of the electric heater during use may be at least about 200 degrees Celsius. The operating temperature of the electric heater during use may be less than about 700 degrees Celsius. The operating temperature of the electric heater during use may be less than about 600 degrees Celsius. The operating temperature of the electric heater during use may be less than about 500 degrees Celsius. The operating temperature of the electric heater during use may be less than about 400 degrees Celsius.

[0048] The electrically insulated substrate may be a ceramic material such as zirconia or alumina. The electrically insulated substrate preferably has a thermal conductivity of 2 watts per meter per Kelvin or less.

[0049] Suitable materials for forming at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped ceramics or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetai (registered trademark), and iron-manganese-aluminum-based alloys.

[0050] In some embodiments, at least one resistive heating element comprises one or more stamped portions of an electrically resistive material (such as stainless steel). Alternatively, at least one resistive heating element may comprise a heating wire or filament (e.g., a wire of Ni—Cr (nickel-chromium), platinum, tungsten, or an alloy).

[0051] The electric heater may be arranged for insertion into the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity. The electric heater may be located within the cavity. The electric heater may be an elongate electric heater. The elongate electric heater may be blade-shaped. The elongate electric heater may be pin-shaped. The elongate electric heater may be conical-shaped. The elongate electric heater may be blade-shaped.

[0052] The controller may be arranged to adjust the supply of power from the power source to the electric heater according to a first heating profile or a second heating profile during a second period of each user experience.

[0053] The controller may be arranged to adjust the supply of power from the power source to the electric heater based on a comparison between the determined rate of temperature rise of the electric heater during a first period of the experience and a predetermined rate threshold according to a first heating profile or a second heating profile during a second period of each user experience.

[0054] As described above, when the aerosol-forming substrate has a relatively low water content, the determined rate of temperature rise of the electric heater during a first period of the experience may exceed a predetermined rate threshold. The controller may be arranged to supply power from the power source to the electric heater according to a first heating profile when the determined rate of temperature rise of the electric heater during a first period of the experience exceeds the above-mentioned predetermined rate threshold. The first heating profile may also be referred to as a "standard heating profile".

[0055] Also, as described above, when the aerosol-forming substrate has a relatively high water content, the determined temperature rise rate of the electric heater during the first period of the experience may be below a predetermined rate threshold. The controller may be arranged to supply power from the power source to the electric heater according to a second heating profile when the temperature rise rate of the electric heater during the first period of the experience is below the above-mentioned predetermined rate threshold. Therefore, the second heating profile may also be referred to as a "wet heating profile".

[0056] The two heating profiles may differ with respect to the total power delivered during the experience. The two heating profiles may differ with respect to the load cycle or load cycles applied during the experience. The two heating profiles may differ with respect to the target operating temperature during the experience.

[0057] In an embodiment where the controller determines the temperature rise rate of the electric heater by determining the time taken for a predetermined temperature rise of the electric heater, the first threshold may be a time threshold. The controller is arranged to supply power to the electric heater according to the first heating profile when the determined time is below the first time threshold. The controller is arranged to supply power to the electric heater according to the second heating profile when the determined time is above the first time threshold. The first time threshold may be a time between about 3 seconds and about 10 seconds. The first threshold may be a time between about 5 seconds and about 7 seconds. The first threshold may be a time of 5.7 seconds.

[0058] The controller is also preferably arranged to determine the ambient temperature.

[0059] When the determined ambient temperature is below the ambient temperature threshold, the controller is preferably arranged to supply power from the power source to the electric heater according to the first heating profile.

[0060] The inventors of the present invention have recognized that when the ambient temperature is low, the rate of temperature rise of an aerosol-forming substrate having a normal water content may be significantly lower. In other words, in a low-temperature environment, the determined rate of temperature rise of a given electric heater when used with an aerosol-forming substrate having a normal water content may be similar to the determined rate of temperature rise of the given electric heater when used with an aerosol-forming substrate having a high water content at normal ambient temperature.

[0061] The inventors of the present invention have recognized that when the ambient temperature is low, it is not always necessary to supply power to the electric heater according to a second heating profile for an aerosol-forming substrate having a high water content. In particular, advantageously, the cold ambient air entering the aerosol-generating device during use is sufficient to maintain the temperature of the generated aerosol at an acceptable level for the user, even when the aerosol-forming substrate has a high water content. The ambient temperature threshold is preferably from about 15 degrees Celsius to about 25 degrees Celsius, more preferably from about 17 degrees Celsius to about 23 degrees Celsius. The ambient temperature threshold may be 18 degrees Celsius.

[0062] The aerosol-generating device may comprise a temperature sensor arranged to sense the ambient temperature, and the controller is arranged to determine the ambient temperature based on a signal received from the temperature sensor. The temperature sensor may comprise a thermistor. The temperature sensor may comprise a thermocouple. The temperature sensor may comprise a semiconductor temperature sensor.

[0063] According to an embodiment of the present invention, there is provided an aerosol-generating system comprising an aerosol-generating device according to the present invention, according to any of the embodiments described herein, and an aerosol-generating article comprising an aerosol-forming substrate.

[0064] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate that releases a volatile compound capable of forming an aerosol when heated.

[0065] The aerosol-forming substrate may contain tobacco.

[0066] The aerosol-forming substrate may comprise a tobacco plug. The tobacco plug may comprise one or more of powders, granules, pellets, fragments, spaghetti, shreds, or sheets containing one or more of tobacco leaves, fragments of tobacco stems, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. Optionally, the tobacco plug may contain additional tobacco or non-tobacco volatile flavor compounds that are released upon heating of the tobacco plug. Optionally, the tobacco plug may also contain capsules containing, for example, additional tobacco or non-tobacco volatile flavor compounds. Such capsules may melt during heating of the tobacco plug. Alternatively, or in addition, such capsules may be crushed before, during, or after heating of the tobacco plug.

[0067] When the tobacco plug contains homogenized tobacco material, the homogenized tobacco material may be formed by aggregating particulate tobacco. The homogenized tobacco material may be in the form of a sheet. The homogenized tobacco material may have an aerosol former content greater than 5 percent on a dry weight basis. Alternatively, the homogenized tobacco material may have an aerosol former content of 5 to 30 weight percent on a dry weight basis. The sheet of homogenized tobacco material may be formed by aggregating particulate tobacco obtained by grinding one or both of tobacco leaf lamina and tobacco leaf stems, or by otherwise comminuting them finely, or alternatively or additionally, the sheet of homogenized tobacco material may contain one or more of, for example, tobacco dust, tobacco fines and other particulate tobacco by-products formed during the processing, handling and transportation of tobacco. The sheet of homogenized tobacco material may contain one or more native binders (i.e., tobacco endogenous binders), or one or more foreign binders (i.e., tobacco exogenous binders), or a combination thereof, to assist in aggregating the particulate tobacco. Alternatively or additionally, the sheet of homogenized tobacco material may contain other additives including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof. The sheet of homogenized tobacco material is preferably formed by a casting process of the type generally comprising casting a slurry containing particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form the sheet of homogenized tobacco material, and removing the sheet of homogenized tobacco material from the support surface.

[0068] The aerosol-generating article may have an overall length of approximately 30 millimeters to approximately 100 millimeters. The aerosol-generating article may have an outer diameter of approximately 5 millimeters to approximately 13 millimeters.

[0069] The aerosol-generating article may comprise a mouthpiece positioned downstream of the tobacco plug. The mouthpiece may be located at the downstream end of the aerosol-generating article. The mouthpiece may be a cellulose acetate filter plug. The mouthpiece preferably has a length of approximately 7 millimeters, but can have a length of approximately 5 millimeters to approximately 10 millimeters.

[0070] The tobacco plug may have a length of approximately 10 millimeters. The tobacco plug may have a length of approximately 12 millimeters.

[0071] The diameter of the tobacco plug may be from approximately 5 millimeters to approximately 12 millimeters.

[0072] In a preferred embodiment, the aerosol-generating article has an overall length of approximately 40 millimeters to approximately 50 millimeters. The aerosol-generating article preferably has an overall length of approximately 45 millimeters. The aerosol-generating article preferably has an outer diameter of approximately 7.2 millimeters.

[0073] According to an embodiment of the present invention, there is provided a method of controlling an aerosol-generating device having a cavity for receiving an aerosol-forming substrate, a rechargeable power source capable of providing at least a first experience and a second experience without an intermediate recharge between the first experience and the second experience, and an electric heater arranged to heat the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity. The method includes the step of controlling the supply of power from the power source to the electric heater. The method also includes the step of determining the rate of temperature rise of the electric heater during a first period of the first experience by determining the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience. The method further includes the step of preventing power from being supplied to the heater in the second experience if the rate of temperature rise of the electric heater during the first period of the first experience is below a predetermined rate threshold and the second experience is started before the expiration of a predetermined time interval from the first experience.

[0074] The controller may evaluate the rate of temperature rise of the heater element during the first period of the first experience at any point during the use of the aerosol generator.

[0075] The controller may evaluate the rate of temperature rise of the heater element of the first experience when the user starts the second experience. At this point, the controller may determine the temperature rise of the heater element of the first experience and, at the same time, may determine the elapsed time since the first experience. If the controller determines that the determined rate of temperature rise is below a predetermined threshold and the elapsed time after the first experience is below a predetermined time interval, the activation of the electric heater for performing the second experience is prevented.

[0076] The predetermined time interval may be in the range of 100 to 300 seconds. The predetermined time interval may be in the range of 120 to 280 seconds. The predetermined time interval may be in the range of 150 to 200 seconds. The predetermined time interval may be about 180 seconds.

[0077] On the other hand, if the controller determines that the determined speed exceeds the predetermined threshold or the elapsed time after the first experience exceeds the predetermined time interval, the activation of the heater is enabled and the user can perform the second user experience.

[0078] Advantageously, the controller may first determine the elapsed time between two consecutive user experiences. If the elapsed time exceeds the predetermined time interval, the second experience can be executed under any circumstances. Thus, in this situation, the evaluation of the rate of temperature rise of the heater element in the first experience is no longer necessary. In this way, the complexity of the controller scheme can be reduced and the required controller operations are fewer.

[0079] The controller of the aerosol generator may evaluate the temperature rise rate of the electric heater at the end of the first experience. If the controller determines that the determined temperature rise rate of the electric heater exceeds a predetermined threshold rate, there is no need to enforce a time delay before the next user experience is delivered. The controller may indicate to the user by any suitable means that a continuous experience is available. This may be done via a visual user interface such as a blinking green LED.

[0080] If the controller determines that the temperature rise rate of the electric heater is below a predetermined threshold, the activation of the electric heater for implementing the second experience is prevented, and the second user experience can only be started after the expiration of a predetermined time interval from the first experience.

[0081] To inform the user of the need to have a timeout before the next user experience can be started, the controller may warn the user via a suitable user interface. By informing the user of the required time delay before the next user experience can be started, the user can already adapt to the required waiting time. This can help enhance the usefulness of the aerosol generator for the user.

[0082] The user interface may include means for indicating to the user the duration of the required timeout period. The user interface may include acoustic, visual, tactile, sensory, or any other suitable means.

[0083] The visual user interface means may include a suitable light source. Advantageously, a light source with a low power consumption may be used. Such suitable light sources include light emitting diodes (LEDs), micro LEDs or organic LED (OLED) devices. These light sources may be operated in a blinking mode to attract the user's attention. For example, a red LED may be operated in a blinking mode throughout a timeout period to inform the user that the aerosol generating device is not yet ready for operation. When the timeout period elapses, the blinking of the LED may stop. This may inform the user that the aerosol generating device is ready for the next experience.

[0084] 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 of the features of another example, embodiment, or aspect described herein.

Example

[0085] Example A: An aerosol generating device, a cavity for receiving an aerosol-forming substrate, an electric heater arranged to heat the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity so as to provide the user with an inhalable aerosol experience, a rechargeable power source capable of providing at least a first experience and a second experience without intermediate recharging between the first experience and the second experience, a controller arranged to control the supply of power from the rechargeable power source to the electric heater, wherein the controller is arranged to determine the rate of temperature rise of the electric heater during the first period of the first experience by determining the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience, An aerosol generator, wherein the controller is further arranged to prevent power from being supplied to the heater in a second experience if, during a first period of a first experience, the temperature rise rate of the electric heater falls below a predetermined rate threshold and the second experience is started before the expiration of a predetermined time interval from the first experience.

[0086] Example B: The aerosol generator according to Example A, wherein the controller comprises a storage element, and the storage element stores the temperature rise rate determined during the last experience.

[0087] Example C: The aerosol generator according to Example A or B, wherein the controller is arranged to check the temperature rise rate and the elapsed time interval between the first experience and the second experience when the user starts the second experience.

[0088] Example D: The aerosol generator according to Example A or B, wherein the controller is arranged to check the temperature rise rate at the end of the first experience.

[0089] Example E: The aerosol generator according to Example D, wherein when the controller determines that the temperature rise rate has fallen below a predetermined threshold, the user is warned of the required timeout via the user interface.

[0090] Example F: The aerosol generator according to Example E, wherein the user alert includes indicating to the user the duration of the timeout. Example G: The aerosol generator according to Example E or F, wherein the user alert includes visually indicating to the user, via an optical element throughout the timeout interval, that the device is not ready for a second experience.

[0091] Example H: The controller is arranged to determine the initial temperature of the electric heater, and the controller is further arranged to supply power from the power source to the electric heater when the initial temperature of the electric heater is below a predetermined temperature threshold, the aerosol generator according to any of the preceding embodiments.

[0092] Example I: The controller is arranged to determine the initial temperature of the electric heater, and the controller is further arranged to prevent the supply of power to the heater when the initial temperature of the electric heater exceeds a predetermined temperature threshold, the aerosol generator according to Example H.

[0093] Example J: The temperature threshold is within the range of 60 degrees Celsius to 120 degrees Celsius, the temperature threshold is within the range of 80 degrees Celsius to 100 degrees Celsius, or the temperature threshold is about 80 degrees Celsius, the aerosol generator according to Example H or I.

[0094] Example K: The electric heater includes a resistive heating element, and the controller is arranged to determine the temperature of the resistive heating element based on the resistance of the resistive heating element, the aerosol generator according to any of Examples H to J.

[0095] Example L: The controller is arranged to supply power from the power source to the electric heater at a constant rate during the first period of the first experience, the aerosol generator according to any of the preceding embodiments.

[0096] Example M: The controller is arranged to supply power from the power source to the electric heater according to a first heating profile during the second period of each experience, the aerosol generator according to any of the preceding embodiments.

[0097] Example N: An aerosol generator according to any of the preceding embodiments, wherein the controller is arranged to adjust the power supply from the power source to the electric heater based on a determined temperature rise rate of the electric heater during a first period of the first experience.

[0098] Example O: An aerosol generator according to any of the preceding embodiments, wherein the controller is arranged to supply power from the power source to the electric heater according to a second heating profile when the determined temperature rise rate of the electric heater during the first period of the experience is below a predetermined threshold during a second period of the experience.

[0099] Example P: An aerosol generator according to any of the preceding embodiments, wherein the controller is arranged to determine the ambient temperature, and the controller is arranged to supply power from the power source to the electric heater according to a first heating profile when the determined ambient temperature is below an ambient temperature threshold.

[0100] Example Q: An aerosol generator according to Example P, further comprising a temperature sensor arranged to sense the ambient temperature, and the controller is arranged to determine the ambient temperature based on a signal received from the temperature sensor.

[0101] Example R: An aerosol generator according to any of Examples A to M, and An aerosol generating article comprising an aerosol-forming substrate, an aerosol generation system.

[0102] Example S: An aerosol generation system according to Example R, wherein the aerosol-forming substrate contains tobacco.

[0103] Example T: A method of controlling an aerosol generating device having a cavity for receiving an aerosol-forming substrate, a rechargeable power source, and an electric heater arranged to heat the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity to provide a user with an inhalable aerosol experience, wherein the rechargeable power source is capable of providing at least a first experience and a second experience without performing an intermediate recharge between the first experience and the second experience, the method comprising: controlling the supply of power from the power source to the electric heater; determining a rate of temperature increase of the electric heater during a first period of the first experience by determining the time taken for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience; preventing power from being supplied to the heater in the second experience if the rate of temperature increase of the electric heater during the first period of the first experience falls below a predetermined rate threshold and if the second experience is initiated before the expiration of a predetermined time interval from the first experience.

[0104] Example U: The method according to Example T, wherein the controller is arranged to check the rate of temperature increase and the elapsed time interval between the first experience and the second experience when the user is initiating the second experience.

[0105] Example V: The method according to Example T, wherein the controller is arranged to check the rate of temperature increase at the end of the first experience.

[0106] Example W: The method according to Example V, wherein if the controller determines that the rate of temperature increase has fallen below a predetermined threshold, the user is warned of the required timeout via a user interface.

[0107] Example X: The method according to Example W, wherein the user alert includes indicating to the user the duration of the timeout.

[0108] Example Y: The method according to Example W or X, wherein the user alert includes visually indicating via an optical element throughout a timeout interval during which the device is not ready for a second experience.

[0109] Example Z: The method according to any one of Examples T to Y, wherein the timeout interval is 60 to 420 seconds, the timeout interval is 120 to 360 seconds, the timeout interval is 150 to 210 seconds, and the timeout interval is about 180 seconds.

[0110] Example ZA: The method according to any one of Examples T to Z, wherein the controller determines an initial temperature of the electric heater and supplies power to the electric heater from a power source when the initial temperature of the electric heater is below a predetermined temperature threshold.

[0111] Example ZB: The method according to any one of Examples T to ZA, wherein the controller determines an initial temperature of the electric heater and prevents power from being supplied to the heater when the initial temperature of the electric heater exceeds a predetermined temperature threshold.

[0112] Example ZC: The method according to Example ZA or ZB, wherein the temperature threshold is within the range of 60 degrees Celsius to 120 degrees Celsius, the temperature threshold is within the range of 80 degrees Celsius to 100 degrees Celsius, or the temperature threshold is about 80 degrees Celsius.

[0113] Example ZD: The method according to any one of Examples ZA to ZC, wherein the electric heater includes a resistive heating element and the controller is arranged to determine the temperature of the resistive heating element based on the resistance of the resistive heating element.

[0114] Example ZE: The method according to any one of Examples T to ZD, wherein the step of controlling the power supply from the power source to the electric heater during the first period includes supplying power to the electric heater from the power source at a constant speed during the first period.

[0115] Example ZF: The method according to any one of Examples T to ZE, wherein the controller supplies power from the power source to the electric heater according to a first heating profile during a second period of each experience.

[0116] Example ZG: The method according to any one of Examples T to ZF, wherein the controller adjusts the power supply from the power source to the electric heater based on the determined temperature rise rate of the electric heater during the first period of the first experience.

[0117] Example ZH: The method according to any one of Examples T to ZG, wherein when the determined temperature rise rate of the electric heater during the first period of the first experience is below a predetermined threshold, the controller supplies power from the power source to the electric heater according to a second heating profile during the second period of the second experience.

[0118] Example ZI: The method according to any one of Examples T to ZH, wherein the controller determines the ambient temperature, and when the determined ambient temperature is below the ambient temperature threshold, the controller supplies power from the power source to the electric heater according to a first heating profile.

[0119] Example ZJ: The method according to Example ZI, further comprising a temperature sensor arranged to sense the ambient temperature, and the controller determines the ambient temperature based on a signal received from the temperature sensor.

[0120] Example ZK: A computer program that, when executed on a computer or other processing device, executes the method according to any one of Examples T to ZJ.

[0121] Features described with respect to one embodiment may equally apply to other embodiments of the present invention.

[0122] Although only by way of illustration, the present invention will be further described with reference to the following accompanying drawings.

Brief Description of the Drawings

[0123]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0124] FIG. 1 shows a cross-sectional view of an aerosol generating device 10 according to an embodiment of the present invention. The aerosol generating device 10 comprises a generally cylindrical housing 12 having a front housing portion 13 and a rear housing portion 15. The front housing portion 13 is slidably removable from the rear housing portion 15 and is shown in FIG. 1 in a partially removed position.

[0125] The front housing portion 13 includes an outer wall 17 and an inner wall 19, and the inner wall 19 defines a cavity 14 for receiving the aerosol forming substrate. A plurality of air inlets 16 for admitting air into the aerosol generating device 12 are defined between the outer wall 17 and the inner wall 19 at the end of the front housing portion 13.

[0126] The rear housing portion 15 includes a cylindrical wall 21 received between the outer wall 17 and the inner wall 19 of the front housing portion 13 when the front housing portion 13 is received within the rear housing portion 15. The cylindrical wall 21 defines a plurality of elongated slots 23.

[0127] Also, the aerosol generating device 10 includes an electric heater 18 positioned on the rear housing portion 15 and extending through an opening 25 defined by the inner wall 19 and into the cavity 14 when the front housing portion 13 is received within the rear housing portion 15. In use, air flows into the aerosol generating device 10 through the air inlets 16, through the slots 23 defined by the cylindrical wall 21, and through the opening 25 into the cavity 14.

[0128] The electric heater 18 includes a base portion 20 and an elongated electrically insulated substrate 22 extending from the base portion 20. The elongated electrically insulated substrate 22 is formed from a ceramic material. The elongated electrically insulated substrate 22 is in the shape of a blade to facilitate insertion of the elongated electrically insulated substrate 22 into the aerosol forming substrate when the aerosol forming substrate is received within the cavity 14.

[0129] The elongated electric heater 18 also includes a plurality of resistive heating elements 24 positioned on the elongated electrically insulated substrate 22.

[0130] The aerosol generating device 10 also further includes a power source 26, a controller 28, and a temperature sensor 29. The controller 28 may be arranged to perform several functions, including controlling the supply of power from the power source 26 to the resistive heating element 24 of the electric heater 18. The power source 26 includes a rechargeable battery.

[0131] The aerosol generating device 10 further includes a power storage element 32 and a user interface 34. The controller 28 is arranged to write to and read from the power storage element 32. In particular, the controller 28 is arranged to store in the power storage element 32 the acceleration rate of the electric heater 18 determined in the last user experience. In this embodiment, the user interface 34 is an LED. The controller 28 is configured to notify the user of the current state of the aerosol generating device 10 via the user interface 34.

[0132] FIG. 2 shows a cross-sectional view of an aerosol generating system 50 comprising the aerosol generating device 10 of FIG. 1 and an aerosol generating article 52 received within the cavity 14 of the aerosol generating device 10. The aerosol generating device 10 is illustrated in FIG. 2 together with a front housing portion 13 fully received within a rear housing portion 15.

[0133] The aerosol generating article 52 includes an aerosol-forming substrate 54 in the form of a tobacco plug, a hollow acetate tube 56, a polymer filter 58, a mouthpiece 60, and an outer wrapper 62. When the aerosol generating article 52 is received within the cavity 14 of the aerosol generating device 10, the elongated electrically insulated substrate 22 and the resistive heating element 24 of the electric heater 18 are received within the tobacco plug.

[0134] The controller 28 of the aerosol generating device 10 is arranged to execute the method 100 illustrated in FIG. 3 when the aerosol generating article 52 is inserted into the cavity 14 and when the aerosol generating device 10 is switched on by the user.

[0135] At the start of the device, the experience is initiated. In step 102, the decision controller 28 determines the ambient temperature using the temperature sensor 29. If the ambient temperature is below 18 degrees Celsius, in step 104, power is supplied from the power source 26 to the electric heater 18 to preheat the electric heater 18.

[0136] To generate the aerosol and provide an experience to the user, power is supplied from the power source 26 to the electric heater 18 according to a first heating profile (step 116). For this purpose, the controller 28 is arranged to supply energy to the electric heater 18 in two consecutive periods. The controller 28 is arranged to supply a constant power from the power source 26 to the electric heater 18 at a constant rate during the first period of the current user experience. The controller 28 is also arranged to determine the rate of temperature rise of the electric heater 18 during this first period. For this purpose, the controller 28 is arranged to determine (step 112) and store (step 114) the time required for the electric heater 18 to be heated from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius during the first period of the user experience. The corresponding data is stored in the power storage element 32 of the aerosol generating device 10. Irrespective of the determined rate of temperature rise of the electric heater 18 during the first period of the current experience, the controller 28 is configured to supply power from the power source 26 to the electric heater 18 during the second period of the current experience according to the first heating profile of step 116 to provide a user experience. The first heating profile typically corresponds to a standard heating profile used under low ambient temperature conditions and also for aerosol generating articles having a normal water content.

[0137] If it is determined that the ambient temperature is below 18 degrees Celsius, steps 112 and 114 of determining and storing the required heating time of the electric heater 18 may be omitted. Such an omission reduces the amount of controller operation required and thereby simplifies the design of the controller scheme.

[0138] When the ambient temperature exceeds 18 degrees Celsius at the start of the experience, the controller 28 determines the elapsed time from the previous user experience in step 106. If the elapsed time from the previous experience exceeds 180 seconds, the controller supplies power from the power supply 26 to the electric heater 18 to preheat the device and is arranged to continue in step 104 in the same manner as the method described above.

[0139] However, if the controller 28 determines in step 106 that the elapsed time from the previous user experience is less than 180 seconds, the controller is arranged to check the rate of temperature rise of the electric heater 18 during the previous user experience. For this purpose, the controller 28 reads out the stored period determined and stored by the controller 28 in the previous user experience from the power storage element 32 of the aerosol generator 10. If the time taken to raise the temperature of the electric heater 18 from 100 degrees Celsius to 250 degrees Celsius is less than 5.7 seconds in the previous user experience, the aerosol formation substrate 54 of the aerosol generating article 52 is considered to have a normal water content. In this case, the risk of occurrence of the high-temperature aerosol effect in the second user experience using the same aerosol generating article 52 is considered low. Therefore, the controller 28 supplies power to the electric heater 18 for preheating (step 104) and continues to provide the user experience according to the first heating profile (step 116).

[0140] If, in step 108, the controller 28 determines that the time taken to raise the temperature of the electric heater 18 from 100 degrees Celsius to 250 degrees Celsius during a previous user experience exceeded 5.7 seconds, the aerosol forming substrate 54 of the aerosol generating article 52 is considered to have an increased water content. In this case, the risk of a high temperature aerosol effect occurring during the current user experience may be higher. To reduce the likelihood of the high temperature aerosol effect occurring, the controller 28 forces a timeout of the electric heater 18 in step 110 and loops the controller 28 to resume the user experience, thereby preventing the supply of electrical energy to the electric heater 18. This procedure is repeated until it is determined in step 106 that the elapsed time from the previous user experience exceeds 180 seconds. When this timing threshold is reached, the controller 28 continues to supply power to the electric heater 18 for preheating (step 104). This embodiment, where the timeout period is included between two consecutive experiences and a standard heating profile is always applied, is particularly envisaged for use in an aerosol generating system where the occurrence of the high temperature aerosol effect is expected to be caused not by an increase in the water content of the aerosol forming substrate but by early consecutive experiences.

[0141] The operation of the controller 28 of the aerosol generating device 10 illustrated in the figure of FIG. 4 is mostly the same as that described in the context of FIG. 3. The main difference is that the controller 28 is arranged to select the heating profile used in the current experience based on the determined rate of temperature rise of the electric heater 18, which is determined in step 112. If, in step 112, the controller 28 determines that the time required for the electric heater 18 to be heated from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius is less than 5.7 seconds, the aerosol forming substrate 54 of the aerosol generating article 52 is considered to have a normal water content and the controller 28 selects a standard heating profile in step 116.

[0142] If in step 112, controller 28 determines that the time required for the electric heater 18 to be heated from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius exceeds 5.7 seconds, the aerosol forming substrate 54 of the aerosol generating article 52 is considered to have an increased water content, and controller 28 selects a wet heating profile in step 118. In each case, the required time Δt is stored in the power storage element 32 in step 114. This parameter is read by controller 28 during the next user experience in step 108. In step 108, for the previous user experience, the required time Δt prev exp is determined to exceed 5.7 seconds, a 180 - second timeout is enforced. Δt prev exp If the stored parameter of Δt is less than 5.7 seconds, or the parameter Δt prev exp has not yet been stored, controller 29 continues to pre - heat the electric heater 18.

[0143] The operation of controller 28 of the aerosol generating device 10 illustrated in the figure of FIG. 5 includes an additional check - in step 120 that is performed after step 108. If in step 106, controller 28 determines that the elapsed time from the last experience is less than 180 seconds, and further if in a previous experience, the heating rate Δt prev exp is determined to have exceeded a predetermined threshold, there is a possibility that the electric heater 18 is still at an elevated temperature. However, consistent aerosol generation can be reliably obtained only when the temperature of the electric heater 18 is below a predetermined temperature threshold. In the embodiment of FIG. 5, the predetermined temperature threshold is set at 80 degrees Celsius. In step 120, if it is determined that the current heater temperature T blade exceeds this threshold, controller 28 prevents the supply of power to the electric heater 18. When the temperature T blade of the electric heater 18 is below the predetermined temperature threshold, the controller starts pre - heating the electric heater 18 in step 104 as described above in the context of FIGS. 3 and 4.

[0144] In FIGS. 6, 7, and 8, slightly different operations of the controller 28 are described. After the start of the device and the start of the experience, the controller 28 uses the temperature sensor 29 in step 102 to determine the ambient temperature again. If the ambient temperature is below 18 degrees Celsius, in step 116, power is supplied from the power supply 26 to the electric heater 18 according to the standard heating profile. Optionally, an additional preheating step 104 may be included as described above with reference to FIGS. 3-5. After the experience is delivered to the user, the aerosol generator 10 is ready for a continuous user experience.

[0145] In step 102, if the controller 28 determines that the ambient temperature is above 18 degrees Celsius, the controller 28 continues to supply power to the electric heater 18. If the controller 28 determines in step 112 that the time required for the electric heater 18 to be heated from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius is less than 5.7 seconds, the aerosol formation substrate 54 of the aerosol generating article 52 is considered to have a normal water content, and the controller 28 provides a user experience according to the first heating profile (step 116). Again, after the experience is delivered to the user, the aerosol generator 10 is ready for a continuous user experience.

[0146] In operation 112, if the controller 28 determines that the time taken for the temperature of the electric heater 18 to rise from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius exceeds 5.7 seconds, the aerosol forming substrate 54 of the aerosol generating article 52 is considered to have an increased water content. However, since the current experience is the first user experience, the controller 28 nevertheless continues to provide the user experience according to the standard heating profile in operation 116. In contrast to previous situations, after the experience is delivered to the user, the aerosol generating device 20 is not ready for a continuous user experience. Instead, since the controller 28 has determined that the currently used aerosol generating article 52 includes an aerosol forming substrate 54 with an increased water content, the controller 28 enforces a 180 - second timeout (operation 122) before it can initiate the next user experience. The user may be directly notified of the need for a timeout at the end of the current user experience. For this purpose, a user interface 34 in the form of a red LED is provided. The controller 28 activates the LED to blink throughout the timeout period. When the blinking of the LED stops, the next user experience can be initiated.

[0147] The operation of the controller 28 of the aerosol generating device 10 shown in the diagram of FIG. 7 is mostly the same as that described in the context of FIG. 6. The main difference is that the controller 28 is arranged to select the heating profile used in the current experience based on the determined rate of temperature rise of the electric heater 18, which is determined in operation 112. If the controller 28 determines in operation 112 that the time required for the electric heater 18 to be heated from a first predetermined temperature of 100 degrees Celsius to a second predetermined temperature of 250 degrees Celsius exceeds 5.7 seconds, the aerosol forming substrate 54 of the aerosol generating article 52 is considered to have an increased water content, and the controller 28 may select a wet heating profile in operation 118, as shown in the diagram of FIG. 7.

[0148] The operation of the controller 28 of the aerosol generator 10 shown in the figure of FIG. 8 includes an additional check-in step 120 that is performed after checking the ambient temperature in step 102. In step 102, if the controller 28 determines that the ambient temperature exceeds 18 degrees Celsius, the controller 28 determines the current temperature of the electric heater 18 in step 120. In step 120, if the current heater temperature T blade is determined to exceed the threshold temperature of 80 degrees Celsius, the controller 28 prevents the supply of power to the electric heater 18. When the temperature T of the electric heater 18 blade is below a predetermined temperature threshold, the controller starts the supply of power to the electric heater 18 as described above with respect to the figure of FIG. 7.

Claims

1. Aerosol generator, A cavity for receiving the aerosol-forming substrate, To provide the user with an inhalable aerosol experience, an electric heater is provided to heat the aerosol-forming substrate when the aerosol-forming substrate is received in the cavity, A rechargeable power supply capable of providing at least the first and second experiences without intermediate recharging between the first and second experiences, The system includes a controller arranged to control the supply of power from the rechargeable power source to the electric heater, The controller is configured to determine the rate at which the electric heater's temperature rises during the first period of the first experience by determining the time it takes for the electric heater's temperature to rise from a first predetermined temperature to a second predetermined temperature during the first period of the first experience. Aerosol generator, wherein the controller is further configured to prevent power from being supplied to the electric heater during a second experience if the rate of temperature rise of the electric heater falls below a predetermined rate threshold during the first period of the first experience and the second experience begins before the expiration of a predetermined time interval from the first experience.

2. The aerosol generator according to claim 1, wherein the controller comprises an energy storage element, and the controller is configured to store the temperature rise rate determined during the last experience.

3. The aerosol generator according to claim 1, wherein the controller is configured to check the rate of temperature rise and the elapsed time interval between the first experience and the second experience when the user begins the second experience.

4. The aerosol generator according to claim 1, wherein the controller is configured to check the rate of temperature rise at the end of the first experience.

5. The aerosol generator according to claim 4, wherein if the controller determines that the temperature rise rate has fallen below a predetermined threshold, the user is warned of the necessary timeout via the user interface.

6. The aerosol generator according to claim 5, wherein the user warning includes indicating to the user the duration of the timeout.

7. The aerosol generator according to claim 5, wherein the user warning visually indicates through an optical element throughout the timeout interval that the device is not ready for the second experience.

8. The aerosol generator according to claim 7, wherein the controller is configured to determine the initial temperature of the electric heater, and the controller is further configured to prevent the supply of power to the electric heater when the initial temperature of the electric heater exceeds the predetermined temperature threshold described above.

9. The aerosol generator according to claim 8, wherein the temperature threshold is within the range of 60 degrees Celsius to 120 degrees Celsius, or within the range of 80 degrees Celsius to 100 degrees Celsius, or the temperature threshold is approximately 80 degrees Celsius.

10. The aerosol generator according to claim 1, wherein the controller is configured to supply power from the power source to the electric heater according to a first heating profile during a second period of each experience.

11. The aerosol generator according to claim 1, wherein the controller is arranged to adjust the supply of power from the power source to the electric heater based on the determined rate of temperature rise during the first period of the first experience.

12. The aerosol generator according to claim 1, wherein the controller is configured to supply power from the power source to the electric heater in accordance with a second heating profile during a second period of the experience, if the determined rate of temperature rise of the electric heater during the first period of the first experience falls below a predetermined threshold.

13. The aerosol generator according to claim 1, wherein the controller is configured to determine the ambient temperature, and the controller is configured to supply power from the power source to the electric heater according to a first heating profile when the determined ambient temperature falls below an ambient temperature threshold.

14. Aerosol generation system, an aerosol generator according to any one of claims 1 to 13, An aerosol generating system comprising an aerosol generating article having an aerosol-forming substrate.

15. A method for controlling an aerosol generator having a cavity for receiving an aerosol-forming substrate, a rechargeable power supply, and an electric heater disposed to heat the aerosol-forming substrate when it is received in the cavity, for example, to provide a user experience of an inhalable aerosol, The rechargeable power supply can provide at least the first experience and the second experience without performing intermediate recharging between the first experience and the second experience. The method described above is A step of controlling the power supply from the power source to the electric heater, A step of determining the rate at which the temperature of the electric heater rises during the first period of the first experience by determining the time required for the temperature of the electric heater to rise from a first predetermined temperature to a second predetermined temperature, A method comprising the step of preventing power from being supplied to the electric heater during a second experience if, during the first period of the first experience, the rate of temperature rise of the electric heater falls below a predetermined rate threshold, and the second experience begins before the expiration of a predetermined time interval from the first experience.

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