Aerosol generating device and method for controlling aerosol generation

Abstract

10. A method of controlling aerosol generation in an aerosol generating device, comprising: adjusting the temperature of a heating element to increase the temperature from an initial 5 temperature to a first temperature, said first temperature being maintained for a first predetermined period of time; adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period of time, the second predetermined period of time following the first predetermined period of time; and controlling power during heating of an aerosol-forming substrate such that the temperature of the heating element is constant and equal to a third temperature for a third predetermined time period, the third temperature corresponding approximately to the first temperature, and the third predetermined period of time following the second predetermined period of time.

Description

[Technical field]

[0001] The present disclosure relates to a method of controlling aerosol generation in an aerosol generating device configured to heat an aerosol-generating article comprising a solid or gel aerosol-forming substrate, and also to an aerosol generating device and a system comprising the aerosol generating device and the aerosol-generating article. [Background technology]

[0002] The aerosol generating device may comprise an electrically operated heat source configured to heat an aerosol generating article including an aerosol-forming substrate to generate an aerosol. Typically, in a heated aerosol generating article, the aerosol is generated by the transfer of heat from the heat source to a physically separate aerosol-forming substrate. In use, volatile compounds are released from the aerosol-forming substrate by the transfer of heat from the heat source to the aerosol-forming substrate and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol that is inhaled by the user.

[0003] A number of handheld aerosol generating devices configured to heat an aerosol-forming substrate of a heated aerosol-generating article are known in the art. These include electrically operated aerosol generating devices in which aerosol is generated by the transfer of heat from one or more electric heating elements of the aerosol generating device to the aerosol-forming substrate of the heated aerosol-generating article. Known handheld electrically operated aerosol generating devices typically comprise a battery, control electronics, and one or more electric heating elements for heating the aerosol-forming substrate of the heated aerosol-generating article.

[0004] It would be desirable to provide an aerosol generating device, and a method of controlling aerosol production in an aerosol generating device, whereby a large amount of volatile compounds is delivered to the user from the first puff, and whereby good delivery of volatile compounds is maintained throughout the user experience. Summary of the Invention

[0005] According to one embodiment, a method for controlling aerosol generation in an aerosol generating device is provided. The device comprises a heating chamber configured to at least partially receive an aerosol-generating article including an aerosol-forming substrate, a heating system associated with a heating element configured to heat the aerosol-forming substrate, and a power source providing power to the heating system. The method includes controlling the power during heating of the aerosol-forming substrate to adjust the temperature of the heating element to increase the temperature from an initial temperature to a first temperature, the first temperature being maintained for a first predetermined period of time; adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period of time, the second predetermined period of time following the first predetermined period of time; and adjusting the temperature of the heating element to be constant and equal to a third temperature within a third predetermined period of time, the third temperature approximately corresponding to the first temperature, and the third predetermined period of time following the second predetermined period of time, to form an aerosol for inhalation by a user.

[0006] Heating the aerosol-forming substrate to form an aerosol for inhalation by a user in three heating modes, with the temperature of the heating element adjusted to each temperature, allows for improved control of aerosol delivery. Specifically, toward the end of a user session in the third heating mode, the amount of desired volatile compound vaporized for inhalation by the user will be depleted. Increasing the temperature of the heating element to approximately the first temperature allows the amount of desired volatile compound vaporized in the aerosol inhaled by the user to remain consistent with that in the first and second heating modes.

[0007] The second predetermined period of time may immediately follow the first predetermined period of time. The third predetermined period of time may immediately follow the second predetermined period of time.

[0008] As used herein with respect to the present invention, the term "aerosol-generating device" is used to describe a device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol. The aerosol-generating device may be a hand-held, electrically operated device.

[0009] As used herein with respect to the present invention, the term "aerosol-generating article" is used to describe an article that includes an aerosol-forming substrate that is heated to generate an inhalable aerosol for delivery to a user. The aerosol-generating article may be disposable.

[0010] As used herein with respect to the present invention, the term "aerosol" is used to describe a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets in a gas. Aerosols can be visible or invisible. Aerosols may include solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, as well as vapors of substances that are normally liquid or solid at room temperature.

[0011] As used herein with respect to the present invention, the term "aerosol-forming substrate" is used to describe a substrate that includes an aerosol-generating material that has the ability to release, upon heating, a volatile compound capable of generating an aerosol.

[0012] The power source is preferably a battery, such as a lithium ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for a period of approximately six minutes, or a multiple of six minutes. In another example, the power source may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heating system.

[0013] As used herein with respect to the present invention, the term "mode" refers to an operating mode that the controller is programmed to implement. For example, in a calibration mode, the controller is configured to implement a pre-programmed calibration process. In a pre-heat mode, the controller is configured to implement a pre-programmed pre-heat process. In a heating mode, the controller is configured to implement a heating process. The term "phase" may be used interchangeably with the term "mode" herein. The controller may be a microcontroller. The controller may comprise a microprocessor, such as a programmable microprocessor. The controller may comprise a non-volatile memory. The aerosol generating device may comprise an interface configured to allow transfer of data from an external device to the controller and from the controller to the external device. The interface may allow software to be uploaded to the controller for execution on the programmable microprocessor. The interface may be a wired interface, such as a micro USB port, or a wireless interface.

[0014] The heating system may include a heating element. The heating system may be configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0015] The heating element may be a resistive heating element which, in use, engages the aerosol-forming substrate to heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0016] The heating system may be inductively coupled to a heating element inside the aerosol-forming substrate, and the heating element may be configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0017] As used herein, the term "inductive coupling" refers to the heating of a heating element, such as a susceptor, when penetrated by an alternating magnetic field. The heating may be caused by the generation of eddy currents in the heating element. The heating may be caused by magnetic hysteresis losses.

[0018] The heating element may be a susceptor. As used herein, the term "susceptor" refers to an element that includes a material capable of converting the energy of a magnetic field into heat. When the susceptor is located in an alternating magnetic field, the susceptor heats up. The heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. The susceptor may be an elongated susceptor. As used herein with respect to the present invention, the term "elongated" is used to describe a susceptor that has a length that is greater than its width. For example, the length of the susceptor may be at least twice its width.

[0019] In the case of internal heating, the first temperature may be 245-285 degrees C. By heating the heating element in a first heating mode to a temperature within this range for a first predetermined period of time, the thermal inertia of the aerosol-forming substrate is overcome and the amount of desired volatile compounds vaporized in the aerosol inhaled by the user is improved from the first puff.

[0020] Controlling the power may further include increasing the temperature of the heating element from ambient temperature to an initial temperature in a preheat mode. The initial temperature may be between 140 and 170 degrees Celsius. The preheat mode may have a duration of between 10 and 20 seconds.

[0021] The pre-heating mode ensures that whatever the physical state of the aerosol-forming substrate (e.g. dry or wet), the duration of the pre-heating phase is sufficient for the aerosol-forming substrate to reach a minimum operating temperature in order to be ready to provide continuous power and reach the first operating temperature as quickly as possible to generate enough aerosol to be inhaled by the user. This is particularly advantageous for aerosol-forming substrates with a high aerosol former content (greater than 30 weight percent), since such substrates typically have a high moisture content after reaching thermal equilibrium.

[0022] Controlling the power may further include calibrating the heating element in a calibration mode, the calibration mode being followed by a pre-heat mode.

[0023] Calibrating the heating element during heating of the aerosol-forming substrate to generate the aerosol (as opposed to during production) advantageously provides a more accurate determination of the calibration values ​​used in temperature control, and thus improved temperature control is achieved.

[0024] The heating system may comprise a heating element, which may be configured to externally heat the aerosol-forming substrate. The heating element may be a resistive heater. The first temperature may be between 180 and 230 degrees Celsius.

[0025] By heating the heating element to a temperature within this range for a first predetermined period of time in a first heating mode, the thermal inertia of the aerosol-forming substrate is overcome and the amount of desired volatile compounds vaporized in the aerosol inhaled by the user is improved from the first puff.

[0026] Controlling the power may further include, in the pre-heat mode, increasing the temperature of the heating element from ambient temperature to an initial temperature, which may be between 140 and 170 degrees Celsius.

[0027] The pre-heating mode ensures that whatever the physical state of the aerosol-forming substrate (e.g. dry or wet), the duration of the pre-heating phase is sufficient for the aerosol-forming substrate to reach a minimum operating temperature in order to be ready to provide continuous power and reach the first operating temperature as quickly as possible to generate enough aerosol to be inhaled by the user. This is particularly advantageous for aerosol-forming substrates with a high aerosol former content (greater than 30 weight percent), since such substrates typically have a high moisture content after reaching thermal equilibrium.

[0028] The one or more second temperatures may correspond approximately to the first temperature. This advantageously reduces the programming required for the controller and therefore the firmware complexity.

[0029] The one or more second temperatures may be different from the first temperature.

[0030] Adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period may include decreasing the temperature of the heating element from the first temperature.

[0031] Reducing the temperature of the heating element in the second heating mode allows the amount of desired volatile compounds vaporized in the aerosol inhaled by the user to remain consistent with the amount in the first heating mode, thereby providing the same sensory experience to the user.

[0032] The one or more second temperatures may be between 190 and 220 degrees Celsius when the aerosol-forming substrate is internally heated. The one or more second temperatures may be between 180 and 230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0033] Reducing the temperature of the heating element from the first temperature may include two successive temperature steps.

[0034] The temperature of the first temperature step may be lower than the temperature of the second temperature step.

[0035] Having two temperature steps within the second heating mode allows for improved control of the amount of vaporized desired volatile compound in the aerosol inhaled by the user, thereby providing the same sensory experience to the user. Furthermore, if the temperature of the second heating step is higher than the temperature of the first heating step, the amount of vaporized desired volatile compound remains consistent even as the amount of desired volatile compound depletes over time with heating.

[0036] Adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period may include increasing the temperature of the heating element from the first temperature.

[0037] The second predetermined period may have a duration of 100 to 280 seconds.

[0038] The power may be controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile of a plurality of heating profiles, each heating profile defining a manner of regulating the temperature of the heating element during each of the heating modes. The heating profiles may be selected based on identifying the aerosol-generating article.

[0039] The power may be controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile of a plurality of heating profiles, each heating profile defining a manner in which the temperature of the heating element is adjusted during the second heating mode.

[0040] The heating profile may be selected based on at least one of identifying the aerosol-generating article and identifying the aerosol-forming substrate.

[0041] The third predetermined period may have a duration between 30 seconds and 120 seconds.

[0042] According to a further embodiment, an aerosol generating device is provided, comprising a heating chamber configured to at least partially receive an aerosol-generating article including an aerosol-forming substrate, a heating system associated with a heating element configured to heat the aerosol-forming substrate, a power source providing power to the heating system, and a controller, the controller being configured to control the power during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user such that in a first heating mode, the controller adjusts the temperature of the heating element to rise from an initial temperature to a first temperature, the first temperature being maintained for a first predetermined period of time, in a second heating mode, the controller adjusts the temperature of the heating element to one or more second temperatures during a second predetermined period of time, the second predetermined period of time following the first predetermined period of time, and in a third heating mode, the controller adjusts the temperature of the heating element to be constant and equal to a third temperature within a third predetermined period of time, the third temperature approximately corresponding to the first temperature, and the third predetermined period of time following the second predetermined period of time.

[0043] The second predetermined period of time may immediately follow the first predetermined period of time. The third predetermined period of time may immediately follow the second predetermined period of time.

[0044] The heating system may include a heating element. The heating system may be configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0045] The heating element may be a resistive heating element which, in use, engages the aerosol-forming substrate to heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0046] The heating system may be inductively coupled to a heating element internal to the aerosol-forming substrate, the heating element being configured to internally heat the aerosol-forming substrate. The first temperature may be between 245 and 285 degrees Celsius.

[0047] Controlling the power may further include, in the pre-heat mode, increasing the temperature of the heating element from an ambient temperature to an initial temperature.

[0048] The initial temperature may be between 140 and 170 degrees Celsius.

[0049] The preheat mode may have a duration of 10 to 20 seconds.

[0050] Controlling the power may further include calibrating the heating element in a calibration mode, the calibration mode being followed by a pre-heat mode.

[0051] The heating system may comprise a heating element configured to externally heat the aerosol-forming substrate. The heating element may be a resistive heater. The first temperature may be between 180 and 230 degrees Celsius.

[0052] Controlling the power may further include, in the pre-heat mode, increasing the temperature of the heating element from ambient temperature to an initial temperature, which may be between 140 and 170 degrees Celsius.

[0053] The one or more second temperatures may correspond approximately to the first temperature.

[0054] The one or more second temperatures may be different from the first temperature.

[0055] Adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period may include decreasing the temperature of the heating element from the first temperature.

[0056] The one or more second temperatures may be between 190 and 220 degrees Celsius when the aerosol-forming substrate is internally heated. The one or more second temperatures may be between 180 and 230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0057] Reducing the temperature of the heating element from the first temperature may include two successive temperature steps.

[0058] The temperature of the first temperature step may be lower than the temperature of the second temperature step.

[0059] Adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period may include increasing the temperature of the heating element from the first temperature.

[0060] The second predetermined period may have a duration of 100 to 280 seconds.

[0061] The power may be controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile of a plurality of heating profiles, each heating profile defining a manner of regulating the temperature of the heating element during each of the heating modes. The heating profiles may be selected based on identifying the aerosol-generating article.

[0062] The power may be controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile of a plurality of heating profiles, each heating profile defining a manner of regulating the temperature of the heating element during the second heating mode. The heating profiles may be selected based on identifying the aerosol-generating article.

[0063] The third predetermined period may have a duration between 30 seconds and 120 seconds.

[0064] According to a further embodiment, there is provided a system comprising an aerosol generating device as described above and an aerosol-generating article including an aerosol-forming substrate.

[0065] The aerosol-forming substrate may comprise one or more aerosol formers, the aerosol-forming substrate comprising a total aerosol former content of 30 weight percent or more.

[0066] As used herein with respect to the present invention, the term "aerosol former" is used to describe a compound that, in use, facilitates the formation of an aerosol and is preferably substantially resistant to thermal decomposition at the operating temperatures of the aerosol-generating article or aerosol-generating system comprising the aerosol-forming substrate.

[0067] As used herein with respect to the present invention, the term "total aerosol former content" is used to describe the combined content of all aerosol formers in an aerosol-forming substrate.

[0068] Unless otherwise stated, the weight percentages of the components of the aerosol-forming substrate listed herein are based on the dry weight of the aerosol-forming substrate.

[0069] The one or more aerosol formers may include at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanedioate, and dimethyl tetradecanedioate.

[0070] The aerosol-forming substrate may be a non-tobacco substrate.

[0071] As used herein with respect to the present invention, the term "non-tobacco substrate" is used to refer to an aerosol-forming substrate that comprises non-tobacco materials.

[0072] The aerosol-forming substrate may be a solid or a gel.

[0073] As used herein with respect to the present invention, the term "solid" is used to describe an aerosol-forming substrate that has a stable size and shape and does not flow at 23°C.

[0074] As used herein with respect to the present invention, the term "gel" is used to describe an aerosol-forming substrate that includes two or more components, one of which is a liquid. A gel is predominantly liquid by weight. A gel is a substantially dilute crosslinked system that, when at steady state, does not exhibit flow, although the liquid phase may still diffuse throughout the system.

[0075] The aerosol-forming substrate may be a solid film.

[0076] As used herein with respect to the present invention, the term "film" is used to describe a solid aerosol-forming substrate having a thickness that is substantially less than its width or length.

[0077] As used herein with respect to the present invention, the term "thickness" is used to describe the smallest dimension between opposing substantially parallel surfaces of a solid aerosol-generating film.

[0078] The aerosol-forming substrate may further comprise nicotine.

[0079] As used herein with respect to the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salt. In embodiments in which the aerosol-forming substrate comprises nicotine base or nicotine salt, the amounts of nicotine recited herein are the amounts of free base nicotine or the amounts of protonated nicotine, respectively.

[0080] The aerosol-forming substrate may comprise natural nicotine, or synthetic nicotine, or a combination of natural and synthetic nicotine.

[0081] The aerosol-forming substrate may further comprise one or more cellulosic agents and one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid.

[0082] The aerosol-forming substrate may have a total cellulosic content of at least 35 percent by weight, and a total carboxylic acid content of at least 0.5 percent by weight.

[0083] As used herein with respect to the present invention, the term "cellulosic agent" is used to describe a cellulosic material. Examples of cellulosic agents include cellulosic film formers, cellulosic reinforcing agents, and cellulosic binders. For example, when an aerosol-forming substrate includes a plurality of cellulosic agents consisting of a cellulosic film former, a cellulosic reinforcing agent, and a cellulosic binder, the term "total cellulosic agent content" describes the combined cellulosic film former content, cellulosic reinforcing agent content, and cellulosic binder content of the aerosol-forming substrate.

[0084] As used herein with respect to the present invention, the term "total carboxylic acid content" is used to describe the combined content of all carboxylic acids in an aerosol-forming substrate. For example, if an aerosol-forming substrate comprises multiple carboxylic acids consisting of benzoic acid and fumaric acid, the term "total carboxylic acid content" describes the combined benzoic acid content and fumaric acid content of the aerosol-forming substrate.

[0085] The aerosol-forming substrate may comprise water.

[0086] The aerosol-forming substrate may have a water content of from 5 percent to 35 percent by weight.

[0087] As used herein, the terms "puffing" and "inhalation" are used interchangeably and are intended to mean the act of a user drawing an aerosol into their body through their mouth or nose. Inhalation includes situations where the aerosol is drawn into the user's lungs, and also situations where the aerosol is only drawn into the user's mouth or nasal passages before being expelled from the user's body.

[0088] As used herein, a "use session" refers to a period of use of a device beginning with activation of the device by a user. A use session may include a pre-heat phase in which the aerosol generating device is configured to supply power to the heating system to heat the aerosol-forming substrate to generate an aerosol. A use session may include a calibration phase for calibrating the heating system to more precisely control the temperature of the heating element. A use session may include a main phase during which the user may inhale the generated aerosol. The main phase may be long enough for multiple puffs. The main phase may be long enough for three, four, five, or six puffs. The main phase may be long enough for seven or more puffs. At the end of the use phase, the aerosol generating device may be configured to stop supplying power to the heating system. The aerosol-forming substrate may be removed from the aerosol generating device at the end of the use session. The aerosol-forming substrate may be replaced in a subsequent use session. The duration of the use session between the start of the use session and the end of the use session may be at least one, two, three, four, five, or six minutes. Preferably, a usage session may have a duration of about a quarter of a minute.

[0089] As used herein, when referring to an aerosol generating device, the terms "upstream" and "forward," as well as "downstream" and "rearward," are used to describe the relative positions of components or portions of components of the aerosol generating device with respect to the direction in which air flows through the aerosol generating device during use. An aerosol generating device according to the invention comprises a proximal end through which aerosol exits the device during use. The proximal end of the aerosol generating device may also be referred to as the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol-generating article may also be referred to as the upstream end. Components or portions of components of the aerosol generating device may be described as being upstream or downstream of one another based on their relative positions with respect to the airflow path of the aerosol generating device.

[0090] As used herein, when referring to an aerosol-generating article, the terms "upstream" and "forward," as well as "downstream" and "backward," are used to describe the relative location of a component or part of a component of the aerosol-generating article with respect to the direction in which air flows through the aerosol-generating article during use of the aerosol-generating article. The aerosol-generating article according to the present invention comprises a proximal end through which aerosol exits the article during use. The proximal end of the aerosol-generating article may also be referred to as the mouth end or the downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol-generating article may also be referred to as the upstream end. The components or parts of the components of the aerosol-generating article may be described as being upstream or downstream from each other based on their relative location between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article. The forward of a component or part of a component of the aerosol-generating article is the part that is at the end closest to the upstream end of the aerosol-generating article. The back of a component or part of a component of the aerosol-generating article is the part that is at the end closest to the downstream end of the aerosol-generating article.

[0091] As used herein, "aerosol cooling element" refers to a component of an aerosol-generating article located downstream of an aerosol-forming substrate, such that in use, the aerosol formed by the volatile compounds released from the aerosol-forming substrate passes through and is cooled by the aerosol cooling element before being inhaled by the user. The aerosol cooling element has a large surface area but produces a low pressure drop. Filters and other mouthpieces that produce a high pressure drop, such as filters made of bundles of fibers, are not considered to be aerosol cooling elements. Chambers and cavities within the aerosol-generating article are not considered to be aerosol cooling elements.

[0092] As used herein, the term "mouthpiece" refers to the portion of an aerosol-generating article, device, or system that is placed into the mouth of a user for directly inhaling the aerosol.

[0093] The present invention is defined in the claims. However, below 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 the other examples, embodiments, or aspects described herein.

[0094] Example 1: A method of controlling aerosol generation in an aerosol-generating device, the device comprising: a heating chamber configured to at least partially receive an aerosol-generating article including an aerosol-forming substrate; a heating system associated with a heating element configured to heat the aerosol-forming substrate; and a power source providing power to the heating system, the method comprising: controlling the power during heating of the aerosol-forming substrate to: adjust the temperature of the heating element to increase the temperature from an initial temperature to a first temperature, the first temperature being maintained for a first predetermined period of time; adjust the temperature of the heating element to one or more second temperatures during a second predetermined period of time, the second predetermined period of time following the first predetermined period of time; and adjust the temperature of the heating element to be constant and equal to a third temperature within a third predetermined period of time, the third temperature corresponding approximately to the first temperature, and the third predetermined period of time following the second predetermined period of time.

[0095] Example 2: The method according to example 1, wherein the heating system comprises a heating element and the heating system is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0096] Example 3: A method according to example 2, wherein the heating element is a resistive heating element, and in use, the heating element engages the aerosol-forming substrate to heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0097] Example 4: A method according to example 1, wherein the heating system is inductively coupled to a heating element inside the aerosol-forming substrate, the heating element being configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0098] Example 5: The method according to one of Examples 2-4, wherein the first temperature is between 245 and 285 degrees Celsius.

[0099] Example 6: The method according to one of Examples 1-5, wherein controlling the power further comprises increasing the temperature of the heating element from an ambient temperature to an initial temperature in a pre-heat mode.

[0100] Example 7: The method according to example 6, wherein the initial temperature is 140-170 degrees Celsius.

[0101] Example 8: The method according to example 6 or 7, wherein the preheat mode has a duration of 10 to 20 seconds.

[0102] Example 9: The method according to one of Examples 6-8, wherein controlling the power further comprises calibrating the heating element in a calibration mode, the calibration mode following the pre-heat mode.

[0103] Example 10: A method according to example 1, wherein the heating system comprises a heating element, the heating element being configured to externally heat the aerosol-forming substrate.

[0104] Example 11: The method according to example 10, wherein the heating element is a resistive heater.

[0105] Example 12: The method according to example 10 or 11, wherein the first temperature is 180 to 230 degrees Celsius.

[0106] Example 13: The method according to one of Examples 10-12, wherein controlling the power further comprises increasing the temperature of the heating element from an ambient temperature to an initial temperature in a pre-heat mode.

[0107] Example 14: The method according to example 13, wherein the initial temperature is 140-170 degrees Celsius.

[0108] Example 15: The method according to any of the preceding examples, wherein the one or more second temperatures correspond approximately to the first temperature.

[0109] Example 16: The method according to one of examples 1-14, wherein the one or more second temperatures are different from the first temperature.

[0110] Example 17: The method according to one of Examples 1-14, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period of time includes reducing the temperature of the heating element from the first temperature.

[0111] Example 18: The method according to example 17, wherein the one or more second temperatures are between 190 and 220 degrees Celsius.

[0112] Example 19: The method according to example 17 or 18, wherein decreasing the temperature of the heating element from the first temperature comprises two successive temperature steps.

[0113] Example 20: The method according to example 19, wherein the temperature of the first temperature step is lower than the temperature of the second temperature step.

[0114] Example 21: The method according to one of Examples 1-14, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period of time includes increasing the temperature of the heating element from the first temperature.

[0115] Example 22: The method according to any one of the preceding examples, wherein the duration of the second predetermined period is between 100 seconds and 280 seconds.

[0116] Example 23: A method according to one of the preceding examples, wherein power is controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile of a plurality of heating profiles, each heating profile defining how to regulate the temperature of the heating element during each of the heating modes.

[0117] Example 24: The method according to example 23, further comprising selecting a heating profile based on identifying the aerosol-generating article.

[0118] Example 25: A method according to one of Examples 1 to 22, wherein power is controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile among a plurality of heating profiles, each heating profile defining a manner in which the temperature of the heating element is adjusted during the second heating mode.

[0119] Example 26: The method according to example 25, further comprising selecting a heating profile based on at least one of identifying the aerosol-generating article and identifying the aerosol-forming substrate.

[0120] Example 27: The method according to any one of the preceding examples, wherein the duration of the third predetermined period is between 30 seconds and 120 seconds.

[0121] Example 28: An aerosol generating device comprising: a heating chamber configured to at least partially receive an aerosol-generating article comprising an aerosol-forming substrate; a heating system associated with a heating element configured to heat the aerosol-forming substrate; a power source to provide power to the heating system; and a controller configured to control the power during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user: in a first heating mode, adjust the temperature of the heating element to increase from an initial temperature to a first temperature, the first temperature being maintained for a first predetermined period of time; in a second heating mode, adjust the temperature of the heating element to one or more second temperatures during a second predetermined period of time, the second predetermined period of time following the first predetermined period of time; and in a third heating mode, adjust the temperature of the heating element to be constant and equal to a third temperature within a third predetermined period of time, the third temperature approximately corresponding to the first temperature, and the third predetermined period of time following the second predetermined period of time.

[0122] Example 29: An aerosol-generating device according to example 28, wherein the heating system comprises a heating element, and the heating system is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0123] Example 30: An aerosol generating device according to example 29, wherein the heating element is a resistive heating element, and in use the heating element engages the aerosol-forming substrate to heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0124] Example 31: An aerosol generating device according to Example 28, wherein the heating system is inductively coupled to a heating element inside the aerosol-forming substrate, and the heating element is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0125] Example 32: The aerosol generating device according to one of Examples 28 to 31, wherein the first temperature is 245 to 285 degrees Celsius.

[0126] Example 33: An aerosol generating device according to one of Examples 28 to 32, wherein controlling the power further comprises increasing the temperature of the heating element from ambient temperature to an initial temperature in the pre-heat mode.

[0127] Example 34: The aerosol generating apparatus according to Example 33, wherein the initial temperature is 140 to 170 degrees Celsius.

[0128] Example 35: An aerosol generating device according to Example 33 or 34, wherein the preheating mode has a duration of 10 to 20 seconds.

[0129] Example 36: An aerosol generating device according to one of Examples 33 to 35, wherein controlling the power further comprises calibrating the heating element in a calibration mode, the calibration mode following the pre-heating mode.

[0130] Example 37: An aerosol generating device according to 28, wherein the heating system comprises a heating element configured to externally heat the aerosol-forming substrate.

[0131] Example 38: An aerosol generating device according to Example 37, wherein the heating element is a resistance heater.

[0132] Example 39: The aerosol generating apparatus according to Example 37 or 38, wherein the first temperature is 180 to 230 degrees Celsius.

[0133] Example 40: An aerosol generating device according to one of Examples 37-39, wherein controlling the power further comprises increasing the temperature of the heating element from ambient temperature to an initial temperature in the pre-heat mode.

[0134] Example 41: The aerosol generating apparatus according to Example 40, wherein the initial temperature is 140 to 170 degrees Celsius.

[0135] Example 42: An aerosol generating device according to one of Examples 28 to 41, wherein the one or more second temperatures correspond substantially to the first temperature.

[0136] Example 43: An aerosol generating device according to one of Examples 28 to 41, wherein the one or more second temperatures are different from the first temperature.

[0137] Example 44: An aerosol generating device according to one of Examples 28 to 41, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period includes lowering the temperature of the heating element from the first temperature.

[0138] Example 45: The aerosol generating device according to Example 44, wherein the one or more second temperatures are between 190 and 220 degrees Celsius.

[0139] Example 46: An aerosol generating device according to example 44 or 45, wherein reducing the temperature of the heating element from the first temperature comprises two successive temperature steps.

[0140] Example 47: An aerosol generating device according to Example 46, wherein the temperature of the first temperature step is lower than the temperature of the second temperature step.

[0141] Example 48: An aerosol generating device according to one of Examples 28 to 41, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period includes increasing the temperature of the heating element from the first temperature.

[0142] Example 49: An aerosol generating device according to Examples 28 to 48, wherein the duration of the second predetermined period is 100 seconds to 280 seconds.

[0143] Example 50: An aerosol generating device according to one of Examples 28 to 49, wherein power is controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile among a plurality of heating profiles, each heating profile defining a manner in which the temperature of the heating element is adjusted during each of the heating modes.

[0144] Example 51: An aerosol generating device according to Example 50, further comprising selecting a heating profile based on identifying the aerosol-generating article.

[0145] Example 52: An aerosol generating device according to one of Examples 28 to 49, wherein power is controlled during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user based on a heating profile among a plurality of heating profiles, each heating profile defining a manner in which the temperature of the heating element is adjusted during the second heating mode.

[0146] Example 53: An aerosol generating device according to Example 52, further comprising selecting a heating profile based on identifying the aerosol-generating article.

[0147] Example 54: An aerosol generating device according to Examples 28 to 53, wherein the duration of the third predetermined period is 30 seconds to 120 seconds.

[0148] Example 55: A system comprising an aerosol-generating device according to one of Examples 28 to 54 and an aerosol-generating article including an aerosol-forming substrate.

[0149] Example 56: The system according to example 55, wherein the aerosol-forming substrate comprises one or more aerosol formers and the aerosol-forming substrate comprises a total aerosol former content of 30 weight percent or more.

[0150] Example 57: The system according to Example 56, wherein the one or more aerosol formers include at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanedioate, and dimethyl tetradecanedioate.

[0151] Example 58: A system according to one of Examples 55-57, wherein the aerosol-forming substrate is a non-tobacco substrate.

[0152] Example 59: A system according to one of Examples 55 to 58, wherein the aerosol-forming substrate is a solid or a gel.

[0153] Example 60: A system according to one of Examples 55 to 59, wherein the aerosol-forming substrate further comprises nicotine.

[0154] Example 61: A system according to one of Examples 55-60, wherein the aerosol-forming substrate further comprises one or more cellulosic agents and one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid.

[0155] Example 62: A system according to Example 61, wherein the aerosol-forming substrate has a total cellulosic agent content of at least 35 weight percent, and a total carboxylic acid content of at least 0.5 weight percent.

[0156] Example 63: A system according to one of Examples 55 to 62, wherein the aerosol-forming substrate comprises water.

[0157] Example 64: A system according to Example 63, wherein the aerosol-forming substrate has a water content of 5 weight percent to 35 weight percent.

[0158] The embodiments will now be further described with reference to the figures. [Brief description of the drawings]

[0159] [Figure 1] FIG. 1 is a schematic cross-sectional view of an aerosol-generating article comprising an aerosol-forming substrate and a susceptor. [Diagram 2] FIG. 2 is a schematic cross-sectional view of an aerosol generating system comprising the aerosol generating article shown in FIG. 1 and an electrically operated aerosol generating device comprising an inductor. [Diagram 3] FIG. 3 is a graph of DC current versus time illustrating the remotely detectable change in electrical current that occurs as the susceptor material undergoes the phase transition associated with its Curie point. [Figure 4] FIG. 4 is a graph of conductance versus time illustrating the change in conductance corresponding to changes in temperature of the susceptor during user operation of the aerosol generating device. [Diagram 5] FIG. 5 shows a schematic cross-sectional view of an aerosol-generating article including an aerosol-forming substrate. [Figure 6] FIG. 6 shows a schematic cross-sectional view of an aerosol generating system comprising the aerosol-generating article shown in FIG. 5 and an electrically operated aerosol generating device comprising a resistive heater for internally heating the aerosol-forming substrate from within the aerosol-forming substrate. [Figure 7] FIG. 7 shows a schematic cross-sectional view of an aerosol generating system comprising the aerosol-generating article shown in FIG. 5 and an electrically operated aerosol generating device comprising a resistive heater for externally heating the aerosol-forming substrate. [Figure 8] FIG. 8 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 6 or FIG. [Figure 9] FIG. 9 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 10] FIG. 10 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 11] FIG. 11 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 12] FIG. 12 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 13] FIG. 13 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 14] FIG. 14 is a graph of temperature versus time illustrating a portion of a heating profile during user operation of the aerosol generating device illustrated in FIG. 2, FIG. 6, or FIG. [Figure 15] FIG. 15 is a flow diagram of a method for controlling aerosol generation in an aerosol generating device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0160] FIG. 1 is a schematic cross-sectional view of an aerosol-generating article 10 in which an aerosol-forming substrate of the aerosol-generating article is inductively heated.

[0161] FIG. 2 is a schematic cross-sectional view of an aerosol generating system 100 comprising the aerosol generating article 10 shown in FIG. 1 and an electrically operated aerosol generating device 110 comprising an inductor.

[0162] The aerosol-generating article 10 shown in Figure 1 comprises an aerosol-generating rod 12, a proximal section 14 located downstream of the aerosol-generating rod 12, and a distal section 16 located upstream of the aerosol-generating rod 12. As shown in Figure 1, the aerosol-generating article 10 has an upstream or distal end 18 and a downstream or proximal end 20.

[0163] The proximal section 14 of the aerosol-generating article 10 comprises a support element 22 located immediately downstream of the aerosol-generating rod 12, an aerosol cooling element 24 located immediately downstream of the support element 22, and a mouthpiece element 42 located immediately downstream of the aerosol cooling element 24.

[0164] The support element 22 comprises a first hollow tubular segment 26. The first hollow tubular segment 26 is in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 26 defines an interior cavity 28 that extends from an upstream end 30 of the first hollow tubular segment to a downstream end 32 of the first hollow tubular segment 20.

[0165] The aerosol cooling element 24 includes a second hollow tubular segment 34. The second hollow tubular segment 34 is in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 34 defines an interior cavity 36 that extends from an upstream end 38 of the second hollow tubular segment to a downstream end 40 of the second hollow tubular segment 34.

[0166] As indicated by the vertical dashed line in FIG. 1, the aerosol-generating article 10 includes a ventilation zone 60 provided at a location along the second hollow tubular segment 34 .

[0167] Mouthpiece element 42 is in the form of a cylindrical plug of low density cellulose acetate.

[0168] The aerosol-generating rod 12 comprises an aerosol-forming substrate. The aerosol-forming substrate may be a solid or a gel. The aerosol-forming substrate comprises one or more aerosol formers, such as glycerin or propylene glycol. The total aerosol former content of the aerosol-forming substrate may be greater than 30 percent by weight. The total aerosol former content of the aerosol-forming substrate may be greater than 40 percent by weight. The total aerosol former content of the aerosol-forming substrate may be greater than 45 percent by weight. The aerosol-forming substrate may be a non-tobacco substrate that does not comprise a tobacco-containing material. Alternatively, the aerosol-forming substrate may comprise a tobacco-containing material. Additionally, the aerosol-forming substrate may comprise water. The aerosol-forming substrate may have a water content of between 5 percent by weight and 35 percent by weight.

[0169] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise one or more cellulosic agents. The aerosol-forming substrate may comprise one or more carboxylic acids. The one or more carboxylic acids may be selected from fumaric acid, maleic acid, and malic acid.

[0170] The aerosol-forming substrate may be a solid aerosol-generating film, and the aerosol-generating rod 12 may comprise an assembly of crimped paper sheets coated with a solid aerosol-generating film.

[0171] The aerosol-generating article 10 comprises a heating element, such as a susceptor 44, located within the aerosol-generating rod 12. As shown in Figure 2, the susceptor 44 is surrounded by the aerosol-forming substrate and extends along the longitudinal axis of the aerosol-generating rod 12 from the upstream end of the aerosol-generating rod 12 to the downstream end of the aerosol-generating rod 12. The susceptor 44 is in direct contact with the aerosol-generating substrate.

[0172] The susceptor 44 may be in the form of a strip having a length of 12 millimeters, a width of 5 millimeters, and a thickness of 60 micrometers. The susceptor 44 includes at least two different materials. The susceptor 44 includes at least two layers, a first layer of a first susceptor material disposed in physical contact with a second layer of a second susceptor material. The first susceptor material and the second susceptor material may each have a Curie temperature, where the Curie temperature of the second susceptor material is lower than the Curie temperature of the first susceptor material. The first material may not have a Curie temperature. The first susceptor material may be aluminum, iron, or stainless steel. The second susceptor material may be nickel or a nickel alloy.

[0173] The distal section 16 of the aerosol-generating article 10 includes an upstream element 46 located immediately upstream of the aerosol-generating rod 12 .

[0174] The upstream element 46 is in the form of a cylindrical plug of cellulose acetate surrounded by a stiff wrapper.

[0175] The aerosol generating system 100 shown in FIG. 2 comprises the aerosol generating article 10 shown in FIG. 1 and a handheld, electrically operated aerosol generating device 110.

[0176] The aerosol generating device 110 comprises a housing 112 defining a heating chamber 114 configured to receive a distal portion of the aerosol-generating article 10 .

[0177] The aerosol generating device 110 includes a power source (not shown) and a heating system (not shown). The heating system includes a controller, a DC / AC converter, and an inductor 116. The power source may be a battery, such as a rechargeable lithium-ion battery. The inductor 116 includes an induction coil. The controller controls the supply of power from the power source to the induction coil.

[0178] In use, the varying or alternating electromagnetic field generated by the induction coil of the inductor 116 induces eddy currents in the susceptor 44 in the aerosol-generating rod 12 of the aerosol-generating article 10, causing heating of the susceptor 44. The heat generated in the susceptor 44 is transferred by conduction to the aerosol-forming substrate in the aerosol-generating rod 12 of the aerosol-generating article 10.

[0179] A user inhales on the mouthpiece element 42 of the aerosol-generating article 10. As the user inhales on the mouthpiece element 42, air is drawn into the aerosol-generating article 10 through the distal end 18. The drawn-in air passes through the upstream element 46 to the aerosol-generating rod 12. Heating of the aerosol-forming substrate releases volatile and semi-volatile compounds, which form an aerosol that is entrained in the drawn-in air as it flows through the aerosol-generating rod 12. The drawn-in air and entrained aerosol pass through the intermediate hollow section 50 of the aerosol-generating article 10, where they cool and condense. The cooled aerosol then passes through the mouthpiece element 42 of the aerosol-generating article 10 into the user's mouth.

[0180] FIG. 3 shows the DC current I drawn from the power source as the temperature of the susceptor 44 (indicated by the dashed line) increases. DC 3 illustrates the relationship of I to time. More specifically, FIG. 3 illustrates the remotely detectable change in DC current that occurs as the susceptor material undergoes a phase transition associated with its Curie point. DC is measured at the input side of the DC / AC converter. For the purposes of this example, the voltage of the power source V DC may be assumed to remain approximately constant.

[0181] As the susceptor 44 is inductively heated, the apparent resistance of the susceptor 44 increases. This increase in resistance is due to the DC current I drawn from the power source. DC, which at constant voltage decreases as the temperature of the susceptor 44 increases. The high frequency alternating magnetic field provided by the inductor induces eddy currents in close proximity to the susceptor surface, an effect known as the skin effect. The resistance within the susceptor 44 depends partly on the electrical resistivity of the first susceptor material, partly on the resistivity of the second susceptor material, and partly on the depth of the skin layer in each material available for the induced eddy currents, and the resistivity is consequently temperature dependent.

[0182] When the second susceptor material reaches its Curie temperature, it loses its magnetic properties. This causes an increase in the surface area available for eddy currents in the second susceptor material, which causes a decrease in the apparent resistance of the susceptor 44. The result is a decrease in the detected DC current I DC There is a temporary increase in resistance, which then begins to drop as the skin depth of the second susceptor material begins to increase, which is seen as a valley (minimum) 310 in FIG.

[0183] As heating continues, the current continues to increase until it reaches a maximum skin depth which coincides with the point at which the second susceptor material loses its naturally occurring magnetic properties. This point is called the Curie temperature and is seen in FIG. 3 as a hill (maximum) 320. At this point, the second susceptor material undergoes a phase change from a ferromagnetic or ferrimagnetic state to a paramagnetic state. At this point, the susceptor 160 is at a known temperature (the Curie temperature, which is a temperature characteristic of a specific material).

[0184] If inductive heating of the susceptor 44 continues after the Curie temperature is reached, the eddy currents generated within the susceptor 44 will flow against the resistance of the susceptor 44, which will cause Joule heating to continue within the susceptor 44, causing the resistance to increase again (resistance has a polynomial dependence on temperature, which for most metallic susceptor materials can be approximated for our purposes to a third order polynomial dependence) and the current will begin to decrease again.

[0185] Thus, when the second susceptor material is heated through a (known) temperature range, it undergoes a reversible phase transition between the valleys 310 and hills 320 shown in Figure 3. As can be seen from Figure 3, the apparent resistance of the susceptor 44, and therefore the onset and end of the reversible phase transition, depend on at least the DC current I drawn from the power source. DC It can be detected remotely by monitoring the DC supply voltage V DC is known, but the DC supply voltage V DC , DC current I DC Thus, the apparent resistance of the susceptor 44, and therefore the onset and end of the phase transition, can be monitored in addition to the conductance value (where conductance is the DC current I DC DC supply voltage V DC ) or resistance (where resistance is the DC supply voltage V DC DC current I DC The DC current I DC , the conductance value, and the resistance value may be referred to as power source parameters.

[0186] As can be seen from FIG. 3, the apparent resistance of the susceptor 44 (and correspondingly the current drawn from the power source I DC ) may vary with the temperature of the susceptor 44 in a strictly monotonic relationship between the onset and end of the reversible phase transition, in other words, between the valleys 310 and the hills 320. The strictly monotonic relationship allows for an unambiguous determination of the temperature of the susceptor 44 from a determination of the apparent resistance (R) or apparent conductance (1 / R), since each determined value of apparent resistance represents only one single value of temperature, and therefore there is no ambiguity in the relationship. The monotonic relationship between the temperature of the susceptor 44 and the apparent resistance in the temperature range in which the second susceptor material undergoes a reversible phase transition allows for the determination and control of the temperature of the susceptor 44, and therefore the temperature of the aerosol-forming substrate.

[0187] The controller adjusts the supply of power provided to the heating system based on the measurement of the power source parameter. The heating system receives a DC current I DC The heating system may optionally include a current sensor (not shown) for measuring a DC supply voltage V DC A voltage sensor (not shown) may be provided to measure the DC current I. The current sensor and the voltage sensor are located on the input side of the DC / AC converter. DC , and optionally a DC supply voltage V DC is the AC power P AC is provided by a feedback channel to the controller to control the further supply of

[0188] The controller may control the temperature of the susceptor 44 by maintaining the measured power source parameter value at a target value that corresponds to a target operating temperature of the susceptor 44. In other words, the controller adjusts the power source parameter value by controlling the power provided to the heating system to regulate the temperature of the susceptor 44.

[0189] To take advantage of the strictly monotonic relationship between the apparent resistance (or apparent conductance) of the susceptor 44 and the temperature of the susceptor 44, during user operation to generate an aerosol, a power source parameter measured at the input side of the DC / AC converter is maintained between a first calibration value corresponding to a first calibration temperature and a second calibration value corresponding to a second calibration temperature. The second calibration temperature is the Curie temperature of the second susceptor material (hill 320 of the current plot in FIG. 3). The first calibration temperature is a temperature at or above the temperature of the susceptor at which the skin depth of the second susceptor material begins to increase, leading to a temporary drop in resistance (valley 310 of the current plot in FIG. 3). Hence, the first calibration temperature is a temperature at or above the temperature at maximum permeability of the second susceptor material. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature. At least the second calibration value is determined by calibration of the susceptor 44, as described in more detail below. The first calibration value and the second calibration value may be stored as calibration values ​​in the memory of the aerosol generating device 110.

[0190] Since the power source parameters will have a polynomial dependence on temperature, the power source parameters will behave in a nonlinear manner as a function of temperature. However, the first and second calibration values ​​are chosen such that this dependence may be approximated as linear between the first and second calibration values, since the difference between the first and second calibration values ​​is small, and such that the first and second calibration values ​​are in the upper part of the operating temperature range. Thus, to adjust the temperature to the target operating temperature, the power source parameters are adjusted according to the first and second calibration values ​​through a linear equation.

[0191] For example, if the first calibration value and the second calibration value are conductance values, a target conductance value G corresponding to the target operating temperature is R teeth,

number

[0192] The first and second calibration values ​​are obtained by performing a calibration process. The controller is programmed to perform the calibration process each time the user operates the aerosol generating device 110. For example, the controller may be configured to enter a calibration mode to perform the calibration process when the user switches on the aerosol generating device 110. The controller may be programmed to enter the calibration mode each time the user inserts an aerosol-generating article 10 into the aerosol generating device 110. Thus, the calibration process is performed during a first heating phase of the aerosol generating device before the main phase in which the user inhales the generated aerosol.

[0193] During the calibration process, the controller controls the DC / AC converter to continuously or continuously supply power to the inductor 116 to heat the susceptor 44. The controller controls the current I drawn by the power source. DC , and optionally a power supply voltage V DC As the susceptor 44 heats up, the measured current decreases until a valley (first turning point) 310 is reached and the current I DC begins to increase. This first turning point 310 corresponds to a local minimum conductance or current value (local maximum resistance value). The controller may record the power source parameter value at the first turning point 310 as a first calibration value.

[0194] The temperature of the susceptor 44 at the first calibration value is the first calibration temperature. As the controller continues to control the power provided by the DC / AC converter to the inductor 116, the controller continues to monitor the power source parameter until a hill (second turning point) 320 is reached. The second turning point corresponds to a maximum current (corresponding to the Curie temperature of the second susceptor material) before the measured current begins to decrease. This second turning point 320 corresponds to a local maximum conductance or current value (local minimum resistance value). The control circuit records the power source parameter value at the second turning point 320 as the second calibration value. The temperature of the susceptor 44 at the second calibration value is the second calibration temperature. When the second turning point 320 is detected, the controller controls the DC / AC converter to discontinue providing power to the inductor 116, resulting in a decrease in the temperature of the susceptor 44 and a corresponding decrease in the measured current.

[0195] Due to the shape of graph 300, this process of successively heating the susceptor 44 to obtain the first and second calibration values ​​may be repeated at least once during the calibration mode. Preferably, the controller adjusts the power based on the power source parameter values ​​obtained from the smallest iteration of the calibration process, which is more reliable since heat has had more time to distribute within the aerosol-forming substrate and susceptor 44.

[0196] The controller is configured to detect turning points 310 and 320 by measuring a sequence of power source parameter values. With reference to Figure 3, the sequence of measured power source parameter values ​​forms a curve, with each value being greater or less than the previous value. The controller is configured to measure the calibration value at the point where the curve begins to flatten out. In other words, the controller records the calibration value when the difference between successive power source parameter values ​​falls below a predefined threshold.

[0197] To further improve the reliability of the calibration process, the controller may be optionally programmed to perform a pre-heating process before the calibration process. For example, if the aerosol-forming substrate is particularly dry or in similar conditions, the calibration process may be performed before heat spreads into the aerosol-forming substrate, reducing the reliability of the calibration value. If the aerosol-forming substrate is wet, the susceptor 44 takes longer to reach the valley temperature (due to the water content in the aerosol-forming substrate).

[0198] To perform the preheating process, the controller is configured to continuously provide power to the inductor 116. As described above with respect to FIG. 3, the measured current begins to decrease with increasing temperature of the susceptor 44 until a turning point 310 corresponding to a minimum measured current (conductance) is reached. At this stage, the controller is configured to wait for a predetermined period of time to allow the susceptor 44 to cool before continuing heating. Thus, the controller controls the DC / AC converter to interrupt the provision of power to the inductor 116. After the predetermined period of time, the controller controls the DC / AC converter to provide power until the turning point 310 corresponding to the minimum measured current is again reached. At this point, the controller controls the DC / AC converter to again interrupt the provision of power to the inductor 116. The controller again waits for the same predetermined period of time to allow the susceptor 44 to cool before continuing heating. This heating and cooling of the susceptor 44 is repeated for a predetermined duration of the preheating process 410. The predetermined duration of the preheating process is 10 to 20 seconds, preferably 11 seconds. The duration of the calibration process is 10-20 seconds. If the aerosol-forming substrate is dry, the first current minimum of the pre-heating process is reached within the predetermined period and the interruption of power is repeated until the end of the predetermined period. If the aerosol-forming substrate has a higher moisture content, the first current minimum of the pre-heating process 410 is reached towards the end of the predetermined period. Thus, carrying out the pre-heating process for a predetermined duration ensures that, regardless of the physical state of the aerosol-forming substrate, there is enough time for the aerosol-forming substrate to reach a minimum operating temperature in order to be ready to be continuously powered and reach the first maximum. This allows for the earliest possible calibration without still running the risk that the aerosol-forming substrate has not reached the first calibration temperature beforehand.

[0199] Specifically, aerosol-forming substrates containing higher aerosol former content (e.g., greater than 30 weight percent) and higher water content (e.g., greater than 5 weight percent) will have higher thermal inertia. Thus, the preheating process ensures that the minimum operating temperature is reached before calibration.

[0200] The pre-heating process may be performed in response to receiving a user input, such as a user activation of the aerosol generating device 110. Additionally or alternatively, the control circuitry may be configured to detect the presence of an aerosol-generating article 10 in the aerosol generating device 110, and the pre-heating process may be performed in response to detecting the presence of an aerosol-generating article 10 in the heating chamber of the aerosol generating device 110.

[0201] 4 is a graph of conductance versus time showing a heating profile of the susceptor 44. The graph illustrates five stages of the heating profile: a pre-heating process 410 performed during a pre-heating mode, a calibration process 420 performed during a calibration mode, and a main phase in which a user inhales an aerosol, including heating modes 430, 440, and 450. Although FIG. 4 is illustrated as a graph of conductance versus time, it will be understood that the controller may be configured to control the heating of the susceptor 44 during each stage of the heating profile based on any measured power source parameter, such as resistance or current, as discussed above.

[0202] Once the calibration process 420 is complete, the controller is configured to discontinue providing power to the heating system to allow the susceptor to cool to the initial temperature. Once the susceptor temperature is detected to be at the initial temperature or after the susceptor temperature has been at the initial temperature for a predetermined period of time, the controller is configured to control the power provided to the heating system to increase the temperature of the susceptor 44 from the initial temperature to a first temperature. Specifically, the controller controls the power provided to the heating system to adjust the conductance to correspond to the first operating temperature of the susceptor 44 for a first predetermined period of time. In one embodiment, the conductance during the first heating mode 430 is 0.75×ΔG, or in other words, 75 percent of the difference in measured conductance between the hills 320 and the valleys 310.

[0203] The first operating temperature is selected so that the desired volatile compounds are vaporized from the substrate while not releasing undesirable compounds that vaporize or evolve at higher temperatures. Additionally, heating the susceptor 44 to the maximum operating temperature of the susceptor 44 immediately after the calibration process 420 improves the amount of desired volatile compounds vaporized, thereby providing improved delivery to the user from the first puff. The first operating temperature of the susceptor 44 may be the maximum operating temperature of the susceptor 44.

[0204] FIG. 5 is a schematic cross-sectional view of an aerosol-generating article 500;

[0205] FIG. 6 is a schematic cross-sectional view of an aerosol generating system 600 comprising the aerosol-generating article 500 of FIG. 5 and an electrically operated aerosol generating device 610 comprising a resistive heater configured to heat the aerosol-generating article 500 from within the aerosol-generating article 500.

[0206] The aerosol-generating article 500 has generally the same structure as the aerosol-generating article 10 described above with respect to Figure 1, where like elements are indicated by like reference numerals. However, it should be noted that the aerosol-generating article 500 does not include a susceptor 44. In addition, the aerosol-generating article does not include an upstream element 46.

[0207] The aerosol generating device 610 comprises a heating chamber 630 for receiving the aerosol generating article 500. A heating element 620 is located within the heating chamber and is positioned to engage the distal end 18 of the aerosol generating article 500. The heating element 620 is an electrically resistive heating element shaped in the form of a blade terminating at a point. The heating element 620 may be formed from a ceramic substrate with one or more resistive heating tracks formed from platinum or another suitable material and disposed on one or both sides of the blade. Alternatively, the heating element 620 may be one or more heating needles or rods extending through the center of the aerosol forming substrate 510. Other alternatives include heating wires or filaments, such as Ni-Cr (nickel chromium), platinum, tungsten, or alloy wires or heating plates. Optionally, the heating element 620 may be disposed within or on a rigid carrier material. For example, the electrically resistive heating element 620 may be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as a ceramic material, and then coated with another insulating material, such as glass. The heater thus formed may be used to both heat the heating element and monitor its temperature during operation.

[0208] When the aerosol-generating article 500 is pushed over the tip of the heating element 620 by applying a force to the aerosol-generating article 500, the heating element 620 penetrates into the aerosol-forming substrate of the aerosol-generating rod 12. The distal end 18 of the aerosol-generating article 500 abuts the end wall 640 of the heating chamber 630, which acts as a stop, preventing further penetration.

[0209] When the aerosol-generating article 500 is properly engaged with the aerosol-generating device 610, the heating element 620 is located within the aerosol-forming substrate in contact with the aerosol-forming substrate. The heating element 620 heats the aerosol-forming substrate by conduction.

[0210] The aerosol generating device 610 includes a power source (not shown) and a heating system (not shown) electrically coupled to the power source. The heating system includes a controller and a heating element 620. The power source may be a battery, such as a rechargeable lithium ion battery. The power source is configured to provide power to the heating system to heat the heating element 620.

[0211] The controller obtains an indication of the temperature of the heating element 620 (e.g., the electrical resistance of the heating element) by measuring the electrical resistance of the heating element 620. The indication of temperature is used to adjust the current supplied to the heating element 620 to maintain the heating element 620 near a target temperature. In other words, the controller adjusts the temperature of the heating element by adjusting the current supplied to the heating element 620.

[0212] This scheme relies on three or more temperature calibration points at which the resistance of the heating element 620 is measured. For temperatures intermediate the calibration points, resistance values ​​are interpolated from the values ​​at the calibration points. The calibration point temperatures are chosen to cover the expected temperature range of the heating element 620 during operation. Calibration of the heating element 620 to obtain the calibration points may be performed at the time of manufacture, and the calibration points may be stored in the memory of the controller.

[0213] When the heating element 620 is heated, the aerosol-forming substrate is heated and a volatile substance is formed. When a user inhales on the proximal end 20 of the aerosol-generating article 500, air is drawn into the aerosol-generating article 500 and the volatile substance condenses to form an inhalable aerosol. The aerosol passes through the proximal end 20 of the aerosol-generating article 500 and into the user's mouth.

[0214] Figure 7 is a schematic cross-sectional view of an aerosol generation system comprising an aerosol-generating device 700 and an aerosol-generating article 500 in which the aerosol-forming substrate of the aerosol-generating article is externally heated. The aerosol-generating article 500 is the aerosol-generating article described above with respect to Figure 5. Although the aerosol-generating article 500 of Figure 5 does not comprise an upstream element 46, the upstream element 46 may be present in the embodiment of Figure 7.

[0215] The aerosol generating device 700 comprises a heating chamber 710 for receiving the aerosol-generating article 500. The heating chamber 710 is formed by a stainless steel tube 730 and has a base 750 at its upstream end.

[0216] The aerosol-generating article 500 is at least partially received within the heating chamber 710. As shown in Figure 7, the aerosol-generating article 500 and the stainless steel tube 730 are configured such that when the aerosol-generating article 500 is received within the heating chamber 710, a proximal end 20 of the aerosol-generating article 500, which a user of the aerosol-generating article 500 may inhale during use, protrudes outside the heating chamber 710 and outside the aerosol generating device 700.

[0217] The aerosol generating device 700 further comprises a heating system comprising a heating element 745. The heating element 745 is bent around and surrounds the upstream end of the stainless steel tube 730. The portion of the stainless steel tube 730 surrounded by the heating element 745 corresponds to the portion of the heating chamber 710 in which the aerosol-forming substrate 725 of the aerosol-generating article 500 is received when the aerosol-generating article 500 is received within the heating chamber 710.

[0218] The heating system further comprises a temperature sensor 740. The temperature sensor 740 may be a Pt1000 type temperature sensor. The temperature sensor 740 is in thermal contact with the heater track of the heating element 745 and is configured to measure the temperature of the heater track of the heating element 745.

[0219] The heating element 745 comprises a first adhesive layer, a first polyimide substrate layer, a heating track, a second adhesive layer, a second polyimide layer, and a heat shrink layer. The temperature sensor 740 is positioned between the second polyimide layer and the heat shrink layer. The temperature sensor 740 comprises a connecting wire for connecting the temperature sensor 740 to a controller 755.

[0220] A first adhesive layer is used to adhere the heating element 745 to the stainless steel tube 730. Sandwiching the heater track between the first and second polyimide layers provides a means to support the heater track in place and also provides electrical insulation between the heater track and other components of the aerosol generating device 700, particularly the stainless steel tube 730. Polyimide is advantageously flexible, electrically insulating and able to withstand the normal operating temperatures of the aerosol generating device, particularly the heater track, during use. The heater track is a continuous conductive track of stainless steel that is deposited on one of the first or second polyimide layers during manufacture. The heater track is configured to heat up when an electrical current is passed through the heater track.

[0221] In other words, the heating element 745 is a resistive heating element 745. The heater track has a resistance of 1.1 ohms at room temperature. A second adhesive layer holds the first polyimide layer and the second polyimide layer together, which keep the heater track in place.

[0222] The heat shrink layer comprises a material capable of withstanding the normal operating temperatures of the aerosol generating device, particularly the heater track, in use.

[0223] The aerosol generating device 700 further comprises a power source 775, such as a battery. The power source 775 and the temperature sensor 740 are connected to a controller 755 via wires and connections not fully shown in FIG. 7. The power source 775 is configured to power the heating element 745 and is connected to a connector of the heater track. The application of heat to the heating element 745 by the power source 775 is controlled by the controller 755.

[0224] The airflow channel 765 extends from the air inlet 760 of the aerosol-generating device 700. Upstream of the heating chamber 710, the airflow channel 765 is defined primarily by airflow channel walls 770. Downstream of the airflow channel walls 770, the airflow channel 765 passes through an air inlet defined in the base 750 of the heating chamber 710. The airflow channel 765 then extends through the heating chamber 710. When the aerosol-generating article 500 is received within the heating chamber 710, the airflow channel 765 passes through the aerosol-generating article 500 and extends through the mouthpiece 42.

[0225] During use of the aerosol-generating system, the aerosol-generating article 500 is inserted into the heating chamber 710 by a user of the system. The user then activates the device, which may be, for example, by pressing a button or by inhaling through the mouthpiece 42 of the aerosol-generating article 500, which is detected by a puff sensor, not shown in FIG.

[0226] Following activation, the controller 755 is configured to control the supply of power from the power source 775 to the heating element 745 to cause the heating track to heat.

[0227] Heat from the heating track is conducted through the stainless steel tube 730 to the aerosol-forming substrate of the aerosol-generating article 500. This heating of the aerosol-forming substrate results in the generated vapor being released into the air that is drawn into the aerosol-forming article 500 via the airflow channels 765. The vapor then cools and condenses into an aerosol. Thus, when the user inhales through the mouthpiece 42, the generated aerosol is drawn through the aerosol-forming article 500 and inhaled by the user.

[0228] Control of heating by controller 755 is based on the temperature signal received from temperature sensor 740. Controller 755 is configured to control the power provided to heating element 745 to adjust the temperature of heating element 745 based on the temperature measured by the temperature sensor.

[0229] Alternatively, the controller 755 may measure the value of the electrical resistance of the heating element 745 to obtain an indication of the temperature of the heating element 745 in the same manner as the controller of the aerosol generation device 610 described with respect to Figure 6. In such a scenario, the temperature sensor 740 is an optional component of the aerosol generation device 700. The controller 755 then adjusts the temperature of the heating element 745 by adjusting the current supplied to the heating element 745 based on the measured resistance value.

[0230] Figure 8 is a graph of heating element temperature versus time showing a portion of a heating profile for an aerosol generating device using resistive heating as described above with respect to Figures 6 and 7. During phase 810, the heating element is at an initial temperature. Phase 810 may be a pre-heat phase in which the controller is programmed to pre-heat the heating element to a predetermined initial temperature for a predetermined duration.

[0231] The pre-heating phase ensures that the duration of the pre-heating phase is sufficient for the aerosol-forming substrate to reach a minimum operating temperature, whatever the physical state of the aerosol-forming substrate (e.g. dry or wet), so as to be ready to supply continuous power and reach the first operating temperature as quickly as possible to generate sufficient aerosol to be inhaled by the user.

[0232] Specifically, since non-tobacco aerosol-forming substrates contain higher aerosol former content (e.g., greater than 30 weight percent) and higher moisture content (e.g., greater than 5 weight percent), aerosol-forming substrates containing non-tobacco materials will have higher thermal inertia than tobacco-derived aerosol-forming substrates. Thus, in the case of non-tobacco aerosol-forming substrates with higher moisture content, the pre-heating process ensures that the minimum operating temperature is reached before the main phase. The duration of the pre-heating mode is 10-20 seconds, preferably 11 seconds.

[0233] Following the pre-heat phase, the controller is configured to enter a first heating mode 820 of the main phase. The first heating mode may be entered in response to a timer indicating that a predetermined duration of the pre-heat phase 810 has elapsed, user actuation of the aerosol generating device, or after detection of a user puff. During the first heating mode 820, the controller rapidly increases the temperature of the heating element from an initial temperature to a first temperature.

[0234] The first temperature is selected such that the desired volatile compounds are vaporized from the substrate while undesirable compounds that vaporize or evolve at higher temperatures are not released. Additionally, rapidly heating the heating element to the first temperature of the heating element improves the amount of desired volatile compounds vaporized, thereby providing improved delivery from the first puff to the user. The first temperature may be the maximum operating temperature of the heating element.

[0235] During phases 820, 830, and 840, the aerosol generating device generates an aerosol for inhalation by the user, and the controller is configured to control the power provided to the heating element to regulate the temperature of the heating element according to a heating profile.

[0236] One or more heating profiles may be stored on a memory of a controller as described with respect to Figures 1, 2, 6 and 7. The controller may be configured to select a heating profile upon user operation of the device for generating an aerosol. For example, the aerosol generating device may be provided with means for identifying an aerosol-generating article or an aerosol-forming substrate and may select a heating profile based on the identification.

[0237] 9-14 are graphs of heating element temperature versus time showing exemplary heating profiles of the heating element during a main phase of heating of the aerosol-forming substrate to form an aerosol for inhalation by a user. The illustrated heating profiles define the temperature of the heating element during each heating mode, and the corresponding duration of each heating mode. However, it will be appreciated that the heating profile may include four or more heating modes.

[0238] Each of the heating profiles in Figures 9-14 shows a shaded area 910, 1010, 1110, 1210, 1310, and 1410. This shaded area corresponds to the calibration phase and optional pre-heating phase of an aerosol generating device having an inductive heating system (Figure 2), or the pre-heating phase of an aerosol generating device having a resistive heating system (Figures 6 and 7).

[0239] Each of the heating profiles in Figures 9-14 illustrates that the temperature of the heating element increases from an initial temperature (not shown) to a first temperature in a first heating mode 920, 1020, 1120, 1220, 1320, 1420. The controller may be configured to enter the first heating mode 920, 1020, 1120, 1220, 1320, 1420 in response to activation by a user of the aerosol generating device or detection of a user puff. The temperature remains constant at the first temperature for the duration of a first period. The initial temperature is above ambient temperature, between 140 and 170 degrees Celsius. In the case of induction heating, the initial temperature may be the temperature reached during the calibration process 420. For example, after reaching a maximum conductance during the calibration process at hill 320, the heating element 44 may be allowed to cool to a temperature between the first and second calibration temperatures. The temperature to which the heating element 44 is cooled may be the initial temperature. In the case of resistive heating, the initial temperature may be the preheat temperature of the heating element 620, 745.

[0240] The first temperature may be between 245 and 285 degrees Celsius when the aerosol-forming substrate is internally heated. The first temperature may be between 180 and 230 degrees Celsius when the aerosol-forming substrate is externally heated. As discussed above, by heating the heating element in the first heating mode 920, 1020, 1120, 1220, 1320, 1420 to a first temperature of the heating element, the thermal inertia of the aerosol-forming substrate is overcome and the amount of desired volatile compounds vaporized in the aerosol inhaled by the user, such as nicotine and aerosol former, is improved from the first puff.

[0241] After the first predetermined period of time, the controller enters a second heating mode 930, 1030, 1130, 1230, 1330, 1340. In the second heating mode, the controller adjusts the temperature of the heating element to one or more second temperatures during the second predetermined period of time. The one or more second temperatures may be between 190 and 220 degrees Celsius when the aerosol-forming substrate is internally heated. The one or more second temperatures may be between 180 and 230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0242] In the second heating mode 930, 1030, 1130, 1230, 1330, 1340, the controller may adjust the temperature of the heating element to approximately correspond to the first temperature, as shown in FIG.

[0243] In the second heating mode 930, 1030, 1130, 1230, 1330, 1430, the controller may adjust the temperature of the heating element to be lower than the first temperature, as shown in Figures 10, 11, 12, and 13. At the end of the first heating mode 920, 1020, 1120, 1220, 1320, 1420, heat will diffuse throughout the aerosol-forming substrate. Thus, lowering the temperature of the heating element in the second heating mode allows the amount of vaporized desired volatile compounds in the aerosol inhaled by the user to remain consistent with the amount in the first heating mode 920, 1020, 1120, 1220, 1320, 1420, thereby providing the same sensory experience to the user.

[0244] In the second heating mode 930, 1030, 1130, 1230, 1330, 1340, the controller may adjust the temperature of the heating element to be higher than the first temperature, as shown in FIG.

[0245] In the second heating mode 930, 1030, 1130, 1230, 1330, 1430, the controller may adjust the temperature of the heating element to a second temperature for the duration of the second period, as shown in Figures 9, 10, and 14. Alternatively, in the second heating mode, the controller may adjust the temperature of the heating element in multiple successive temperature steps. For example, Figure 11 shows two temperature steps having the same duration, where the temperature of the heating element is lower during the first temperature step than during the second temperature step. Figure 12 shows two temperature steps, where the temperature of the heating element is lower during the first temperature step than during the second temperature step, and where the duration of the first temperature step is shorter than the duration of the second temperature step.

[0246] In the third heating mode 940, 1040, 1140, 1240, 1340, 1440, the controller is configured to adjust the temperature of the heating element to a third temperature. The temperature of the heating element remains constant at the third temperature for a predetermined duration of a third period. As shown in Figures 9-14, the third temperature corresponds approximately to the first temperature. At this stage of the use session, the aerosol-forming substrate will have become depleted of the desired volatile compound. Thus, increasing the temperature of the heating element to approximately the first temperature allows the amount of vaporized desired volatile compound in the aerosol inhaled by the user to remain consistent with the amount in the first and second heating modes.

[0247] Each of the predetermined periods may be of equal length or of different length. For example, a first predetermined period may be shorter than a subsequent second predetermined period, for example, as shown in Figures 9, 10, 11, and 13. Additionally or alternatively, the first predetermined period may be shorter than a third predetermined period, for example, as shown in Figures 10 and 11. The second predetermined period may be longer than at least one of the first and third predetermined periods, for example, as shown in Figures 9-14. The first and third predetermined periods may have durations, for example, as shown in Figure 13.

[0248] The length of the first predetermined period may be between 40 seconds and 150 seconds, the length of the second predetermined period may be between 100 seconds and 280 seconds, and the length of the third predetermined period may be between 30 seconds and 120 seconds.

[0249] The length of the first predetermined period is selected such that the aerosol-forming substrate is capable of providing good delivery of the volatilized desired compound within the aerosol, the first predetermined period being at least shorter than the second predetermined period ensuring good aerosol delivery to the user while ensuring consistency of the user experience throughout an entire use session.

[0250] The length of the second predetermined period being at least longer than the first predetermined period, particularly when the second temperature is lower than the first temperature, provides improved control of the amount of vaporized desired volatile compound in the aerosol inhaled by the user, thereby providing a consistent user experience for as long as possible throughout an entire use session.

[0251] FIG. 15 is a flow chart illustrating a method of controlling aerosol generation in one of the aerosol generating devices by heating a heating item inserted into the heating chamber of the aerosol generating device, as described above.

[0252] The method begins at step 1510 when a user activates heating of the heating element, as described above. For example, the user may press one or more buttons on the aerosol generating device to initiate heating of the heating element. Additionally or alternatively, the user may insert an aerosol-generating article into the heating chamber of the aerosol generating device to cause heating of the heating element.

[0253] The method then proceeds to step 1520, where the controller controls the power provided to the heating system to increase the temperature of the heating element from ambient temperature to the initial temperature. During step 1520, the controller is in a pre-heat mode and maintains the temperature of the heating element at the initial temperature for a predetermined period of time.

[0254] When the aerosol generating device heats the heating element by induction (the aerosol generating device of FIG. 2), after the pre-heat mode, a calibration process follows in step 1530 to obtain a first calibration value and a second calibration value. The controller uses the first calibration value and the second calibration value to adjust the temperature of the susceptor as described above.

[0255] At step 1540, following step 1520 for an aerosol generating device using resistive heating, and following step 1530 for an aerosol generating device using inductive heating, the controller enters a first heating mode. In the first heating mode, the controller adjusts the temperature of the heating element to increase the temperature from an initial temperature to a first temperature. The first temperature is maintained for a first predetermined period of time.

[0256] At the end of the first predetermined period, the controller enters a second heating mode at step 1550. In the second heating mode, the controller adjusts the temperature of the heating element to a second temperature. The second temperature may be maintained for the second predetermined period. Alternatively, the second temperature may be a first step of a plurality of temperature steps, each having a predefined duration, where the sum of the predefined durations of each temperature step is the duration of the second predetermined period of the second heating mode. The second temperature may be lower than the first temperature, approximately equal to the first temperature, or higher than the first temperature.

[0257] At the end of the second predetermined time period, the controller enters a third heating mode in step 1560. In the third heating mode, the controller adjusts the temperature of the heating element to a third temperature. The third temperature is maintained for a third predetermined time period. The third temperature is approximately equal to the first temperature and is maintained constant for the duration of the third time period.

[0258] It is understood that the figures are for illustrative purposes and are not drawn to scale. Moreover, it will be understood that the aerosol-generating articles and aerosol-generating devices shown in the figures and described in detail above may have additional elements to those discussed. Similarly, an aerosol-generating article or aerosol-generating device according to the embodiments discussed herein may have fewer elements. Moreover, it will be apparent to one of ordinary skill in the art that the various dimensions for the elements discussed herein with respect to the various embodiments discussed herein are merely exemplary and that suitable alternative dimensions for the various elements may be selected.

[0259] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be 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 recited herein. Thus, in this context, the number A is understood as A±10%. Within this context, the number A may be considered to include a numerical value that is within the typical standard error for the measurement of the property that the number A modifies. The number A may, in some instances used in the appended claims, deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel properties 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 recited herein. Furthermore, in the context of the present invention, the expression that a number A "approximately corresponds" to a number B is to be understood as the number A being equal to B ±10%.

Claims

1. A method for controlling aerosol generation in an aerosol generation system, wherein the system An aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a non-tobacco substrate, the total aerosol-forming content of the aerosol-forming substrate is 30% by weight or more, and the water content of the aerosol-forming substrate is 5% by weight to 35% by weight; and an aerosol generating device comprising an aerosol generating device having a heating chamber configured to at least partially receive the aerosol generating article, a heating system associated with a heating element configured to heat the aerosol-forming substrate, and a power source providing power to the heating system, wherein the method comprises controlling the power during heating of the aerosol-forming substrate to form an aerosol for inhalation by a user. In the first heating mode, the temperature of the heating element is adjusted to increase the temperature from the initial temperature to a first temperature, and the first temperature is maintained for a predetermined first period of time. In a second heating mode, for adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period, wherein the second predetermined period follows the first predetermined period, A method for adjusting the temperature of the heating element to be constant and equal to a third temperature within a third predetermined period, wherein the third temperature is substantially equivalent to the first temperature, and the third predetermined period follows the second predetermined period.

2. The method according to claim 1, wherein the heating system is inductively coupled to the heating element inside the aerosol-forming substrate, and the heating element is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

3. The method according to claim 1, wherein the first temperature is 245 to 285 degrees Celsius.

4. The method according to claim 1, wherein the heating system comprises the heating element, and the heating element is configured to externally heat the aerosol-forming substrate.

5. The method according to claim 4, wherein the first temperature is 180 to 230 degrees Celsius.

6. The method according to any one of claims 1 to 5, wherein adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period is to lower the temperature of the heating element from the first temperature.

7. The method according to claim 6, wherein one or more of the second temperatures are 190 to 220 degrees Celsius.

8. an aerosol generation system, An aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a non-tobacco substrate, the total aerosol-forming content of the aerosol-forming substrate is 30% by weight or more, and the water content of the aerosol-forming substrate is 5% by weight to 35% by weight, Aerosol generator, A heating chamber configured to at least partially receive the aerosol-generating article, A heating system associated with a heating element configured to heat the aerosol-forming substrate, A power source for supplying power to the aforementioned heating system, An aerosol generator comprising a controller configured to form an aerosol for inhalation by a user.

9. The aerosol generating system according to claim 8, wherein the heating system is inductively coupled to the heating element inside the aerosol forming substrate, and the heating element is configured to internally heat the aerosol forming substrate.

10. The aerosol generating system according to claim 9, wherein the first temperature is 245 to 285 degrees Celsius.

11. The aerosol generating system according to claim 8, wherein the heating system comprises a heating element configured to externally heat the aerosol forming substrate.

12. The aerosol generating system according to claim 11, wherein the first temperature is 180 to 230 degrees Celsius.

13. The aerosol generating system according to any one of claims 8 to 12, wherein adjusting the temperature of the heating element to one or more second temperatures during the second predetermined period includes lowering the temperature of the heating element from the first temperature.

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