Aerosol generator and method for controlling aerosol generation thereof

Abstract

A method for controlling aerosol generation in an aerosol generating system, the system comprising: an aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol-forming substrate contains 30 weight percent aerosol-forming material; a heating chamber configured to receive the aerosol generating article at least partially; a heating system associated with a heating element configured to heat the aerosol-forming substrate; and a heating system A method comprising a power supply for supplying power to a device, wherein the power is controlled during heating of an aerosol-forming substrate that forms an aerosol inhaled by a user, adjusting the temperature of a heating element (1540) to rise from an initial temperature to a first temperature, the first temperature being maintained for a first predetermined period, immediately after the first predetermined period, adjusting the temperature of the heating element (1550) to one or more second temperatures during a second predetermined period, immediately after the second predetermined period, adjusting the temperature of the heating element (1560) to a constant and equal third temperature during a third predetermined period, the third temperature being approximately equal to the first temperature.

Description

[Technical Field]

[0001] This disclosure relates to a method for controlling aerosol generation in an aerosol generator configured to heat an aerosol generating article comprising a solid or gel aerosol-forming substrate. This disclosure also relates to an aerosol generator and a system comprising an aerosol generator and an aerosol generating article. [Background technology]

[0002] An aerosol generator may include an electrically operated heat source configured to generate an aerosol by heating an aerosol-generating article containing an aerosol-forming substrate. Typically, in a heated aerosol-generating article, the aerosol is generated by heat transfer from the heat source to an aerosol-forming substrate that is physically separated from the heat source. During use, volatile compounds are released from the aerosol-forming substrate by heat transfer 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] Numerous handheld aerosol generators configured to heat the aerosol-forming substrate of a heated aerosol-generating article are known in the art. These include electrically operated aerosol generators in which an aerosol is generated by heat transfer from one or more electric heating elements of the aerosol generator to the aerosol-forming substrate of the heated aerosol-generating article. Known handheld electrically operated aerosol generators 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 is desirable to provide an aerosol generator and a method for controlling aerosol generation in an aerosol generator, such that a large amount of volatile compounds are delivered to the user from the initial inhalation, and that good delivery of volatile compounds is maintained throughout the entire user experience. [Overview of the Initiative]

[0005] According to one embodiment, a method is provided for controlling aerosol generation in an aerosol generating device. The device comprises a heating chamber configured to at least partially receive an aerosol generating article containing an aerosol-forming substrate, wherein the aerosol-forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol-forming substrate contains more than 30 weight percent aerosol-forming material; a heating system associated with a heating element configured to heat the aerosol-forming substrate; and a power supply for supplying power to the heating system. The method includes controlling the power while heating the aerosol-forming substrate to form an aerosol for the user to inhale, thereby adjusting the temperature of the heating element to rise from an initial temperature to a first temperature, the said first temperature being maintained for a first predetermined period; immediately thereafter the first predetermined period, adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period; immediately thereafter the second predetermined period, adjusting the temperature of the heating element to a constant and equal third temperature during a third predetermined period, the third temperature being approximately the first temperature.

[0006] By heating a cellulosic aerosol-forming substrate containing more than 0.1 weight percent and no more than 10 weight percent tobacco particles, and more than 30 percent aerosol-forming material, an improved amount of the desired volatile compound can be vaporized for user inhalation. In particular, when combined with raising the temperature of the heating element to approximately the first temperature immediately after a second predetermined period, improved aerosol delivery is achieved, consistent throughout the entire user experience, including multiple puffs, e.g., 8 to 12 or more puffs. Furthermore, the specific tobacco content allows for a reduction in nicotine content, resulting in improved sensory benefits during aerosol inhalation.

[0007] As used herein in relation to the present invention, the term "aerosol generator" is used to describe a device that generates an aerosol by interacting with an aerosol-forming substrate of an aerosol-generating article. The aerosol generator may be a handheld, electrically operated device.

[0008] As used herein in relation to the present invention, the term "aerosol-generating article" is used to describe an article comprising an aerosol-forming substrate that is heated to generate an aerosol that can be inhaled for delivery to a user. The aerosol-generating article may be disposable.

[0009] As used herein in relation to the present invention, the term "aerosol" is used to describe the dispersion of solid particles, or droplets, or combinations of solid particles and droplets, in a gas. Aerosols may be visible or invisible. Aerosols may include not only vapors of substances that are normally liquid or solid at room temperature, but also solid particles, or droplets, or combinations of solid particles and droplets.

[0010] As used herein in relation to the present invention, the term "aerosol-forming substrate" is used to describe a substrate comprising an aerosol-generating material having the ability to release a volatile compound that can generate an aerosol upon heating.

[0011] As used herein in relation to the present invention, the term "aerosol-forming compound" is used to describe a compound that facilitates aerosol formation when in use and is substantially resistant to thermal decomposition at the operating temperature of an aerosol-generating article or an aerosol-generating system comprising an aerosol-generating article or aerosol-forming substrate.

[0012] As used herein in relation to the present invention, the term "total aerosol-forming content" is used to describe the combined content of all aerosol-forming elements in the aerosol-forming substrate.

[0013] 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.

[0014] As used herein in relation to the present invention, the term "cellulose" is used to represent cellulosic substances such as cellulosic film-forming agents, cellulosic reinforcing agents, and cellulosic binders. When the aerosol-forming substrate comprises a plurality of cellulosic substances consisting of cellulosic film-forming agents, cellulosic reinforcing agents, and cellulosic binders, the term "total cellulosic agent content" describes the combined cellulosic film-forming agent content, cellulosic reinforcing agent content, and cellulosic binder content of the aerosol-forming substrate.

[0015] Preferably, the power source is 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 sufficient capacity to enable continuous aerosol generation for a period of approximately six minutes, or multiples of six minutes. In another embodiment, the power source may have sufficient capacity to enable a predetermined number of fume extractions or discontinuous startups of the heating system.

[0016] As used herein in relation to the present invention, the term "mode" refers to an operating mode programmed for a controller to perform. For example, in calibration mode, the controller is configured to perform a pre-programmed calibration process. In preheating mode, the controller is configured to perform a pre-programmed preheating process. In heating mode, the controller is configured to perform a heating process. The term "phase" may be used herein interchangeably with the term "mode."

[0017] The controller may be a microcontroller. The controller may comprise a microprocessor such as a programmable microprocessor. The controller may comprise non-volatile memory. The aerosol generating device may comprise an interface configured to enable transfer of data from an external device to the controller and from the controller to an external device. The interface may be capable of uploading software to the controller for execution on the programmable microprocessor. The interface may be a wired interface such as a micro USB port or may be a wireless interface. <U+

[0018] 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 body.

[0019] The heating element may be a resistive heating element that engages with the aerosol-forming substrate during use to heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0020] The heating system may be inductively coupled to a heating element within the aerosol-forming substrate, and the heating element may be configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0021] As used herein, the term "inductive coupling" refers to 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 within the heating element. The heating may be caused by magnetic hysteresis losses.

[0022] The heating element may be a susceptor. As used herein, the term "susceptor" refers to an element that includes a material having the ability to convert the energy of a magnetic field into heat. When the susceptor is positioned within an alternating magnetic field, the susceptor is heated. The heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced within the susceptor, depending on the electrical and magnetic properties of the susceptor material. The susceptor may be an elongate susceptor. As used herein with respect to the present invention, the term "elongate" is used to describe a susceptor having a length greater than its width. For example, the length of the susceptor may be at least twice its width.

[0023] In the case of internal heating, the first temperature may be between 245 and  285 degrees Celsius. By heating the heating element 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 the desired vaporized volatile compound in the aerosol inhaled by the user is improved from the first puff.

[0024] Controlling the power may further include increasing the temperature of the heating element from ambient temperature to an initial temperature in the preheating mode. The initial temperature may be between 140 and 170 degrees Celsius. The preheating mode may have a duration of 10 to 20 seconds.

[0025] The preheating mode supplies continuous power and is ready to reach the first operating temperature as quickly as possible in order to generate sufficient aerosol for inhalation by the user, regardless of the physical state of the aerosol-forming substrate (e.g., dry or wet). This ensures that the duration of the preheating phase is sufficient for the aerosol-forming substrate to reach the minimum operating temperature. This is particularly advantageous for aerosol-forming substrates having a high aerosol-forming agent content (greater than 30% by weight). Such substrates typically have a high moisture content after reaching thermal equilibrium.

[0026] Controlling the power may further include calibrating the heating element in calibration mode, and the calibration mode is followed by a preheating mode.

[0027] Calibrating the heating element during the heating of the aerosol-forming substrate to generate aerosols (as opposed to during manufacturing) is advantageous because it provides a more accurate determination of the calibration values ​​used in temperature control, and thus improved temperature control is achieved.

[0028] The heating system may include a heating element, which may be configured to externally heat the aerosol-forming substrate. The heating element may be a resistance heater. The first temperature may be 180 to 230 degrees Celsius.

[0029] By heating the heating element to a temperature within this range for a predetermined period, the thermal inertia of the aerosol-forming substrate is overcome, and the amount of vaporized desired volatile compounds in the aerosol inhaled by the user is improved from that of the first smoke inhalation.

[0030] Controlling the power may further include increasing the temperature of the heating element from ambient temperature to an initial temperature in preheating mode. The initial temperature may be between 140 and 170 degrees Celsius.

[0031] The preheating mode ensures that the duration of the preheating phase is sufficient for the aerosol-forming substrate to reach its minimum operating temperature, so that it can be supplied with continuous power to generate enough aerosol to be inhaled by the user, regardless of the physical state of the aerosol-forming substrate (e.g., dry or wet), and so that it can reach the first operating temperature as quickly as possible. This is particularly advantageous for aerosol-forming substrates with a high aerosol-forming content (more than 30 weight percent), as these substrates typically have a high moisture content after reaching thermal equilibrium.

[0032] One or more second temperatures may approximate the first temperature. This is advantageous because it simplifies the programming required for the controller and therefore reduces the complexity of the firmware.

[0033] One or more of the second temperatures may be different from the first temperature.

[0034] Adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period may include lowering the temperature of the heating element from the first temperature.

[0035] By lowering the temperature of the heating element over a second predetermined period, the amount of the desired volatile compound vaporized in the aerosol inhaled by the user matches the amount inhaled by the user during the first predetermined period, thereby providing the user with the same sensory experience.

[0036] One or more second temperatures may be 190-220 degrees Celsius when the aerosol-forming substrate is internally heated. One or more second temperatures may be 180-230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0037] Lowering the temperature of the heating element from a first temperature may include lowering the temperature of the heating element to a second temperature, which is maintained for a second predetermined period.

[0038] Lowering the temperature of the heating element over a second predetermined period contributes to the technical effect of achieving consistent and sufficient aerosol delivery with each inhalation throughout the entire user experience, which typically involves 8 to 12 inhalations over a period of approximately 3.5 to 6 minutes.

[0039] Lowering the temperature of the heating element from a first temperature may involve two consecutive temperature steps.

[0040] The temperature in the first temperature step may be lower than the temperature in the second temperature step.

[0041] Having two temperature steps within a second predetermined period allows for improved control over the amount of the desired volatile compound vaporized in the aerosol inhaled by the user, thereby providing the user with the same sensory experience. Furthermore, if the temperature of the second heating step is higher than the temperature of the first heating step, the amount of the desired vaporized volatile compound remains consistent, even if the amount of the desired volatile compound is depleted over time with heating.

[0042] Adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period may include raising the temperature of the heating element from the first temperature.

[0043] The duration of the second predetermined period may be between 100 and 280 seconds.

[0044] The duration of the third predetermined period may be between 30 and 120 seconds.

[0045] The duration of the first predetermined period may be shorter than at least one of the durations of the second predetermined period and the third predetermined period. The durations of the second predetermined period and the third predetermined period may be approximately the same. This provides the advantage of maintaining a constant aerosol delivery.

[0046] Power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, the heating profile defining a method for adjusting the temperature of the heating element during each predetermined period.

[0047] The power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, the heating profile defining a method for adjusting the temperature of the heating element over a second predetermined period.

[0048] The heating profile may be one of several heating profiles. This method may further include selecting a heating profile based on identifying one or more characteristics of the aerosol-generating article.

[0049] One or more characteristics of an aerosol generator may include the type of aerosol-forming substrate and the type of aerosol-generating article.

[0050] One or more aerosol-forming bodies may contain at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanediate, and dimethyl tetradecanediate.

[0051] The aerosol-forming substrate may be a solid or a gel.

[0052] The aerosol-forming substrate may further contain nicotine. The total nicotine content of the aerosol-forming substrate may be 1 to 2 weight percent.

[0053] The aerosol-forming substrate may contain one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid.

[0054] The aerosol-forming substrate may have a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent.

[0055] The aerosol-forming substrate may contain water.

[0056] The aerosol-forming substrate may have a water content of 5% to 35% by weight.

[0057] Tobacco particles can be homogeneously dispersed within the aerosol-forming substrate. This allows for the uniform generation of aerosols inhaled by the user from the desired vaporized volatile compounds throughout the aerosol-forming substrate and throughout the user experience.

[0058] Tobacco particles can be as small as 60-80 micrometers.

[0059] The aerosol-forming substrate contains tobacco particles at a weight percentage of 1 percent or less.

[0060] The aerosol-forming substrate contains more than 0.5 weight percent and less than 5 weight percent tobacco particles.

[0061] The aerosol-forming substrate may contain a total aerosol-forming material content of more than 35% by weight and less than 40% by weight.

[0062] A further embodiment provides an aerosol generating system comprising: an aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol-forming substrate contains more than 30 weight percent aerosol-forming material; 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 supply providing power to the heating system; and a controller. The controller is configured to control the power while heating the aerosol-forming substrate to form an aerosol for the user to inhale, thereby adjusting the temperature of the heating element to rise from an initial temperature to a first temperature, which is maintained for a first predetermined period; immediately thereafter, during a second predetermined period, the temperature of the heating element is adjusted to one or more second temperatures; immediately thereafter, during a third predetermined period, the temperature of the heating element is adjusted to a constant and equal third temperature, where the third temperature corresponds approximately to the first temperature.

[0063] The heating system may include a heat-generating element. The heating system may be configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate.

[0064] The heating element may be a resistance heating element that engages with the aerosol-forming substrate during use and heats the aerosol-forming substrate from within.

[0065] The heating system may be inductively coupled to an internal heating element with respect to the aerosol-forming substrate, and the heating element may be configured to internally heat the aerosol-forming substrate. The first temperature may be 245 to 285 degrees Celsius.

[0066] Controlling the power may further include increasing the temperature of the heating element from ambient temperature to the initial temperature in preheating mode.

[0067] The initial temperature may be between 140 and 170 degrees Celsius.

[0068] The preheating mode may have a duration of 10 to 20 seconds.

[0069] Controlling the power may further include calibrating the heating element in calibration mode, and the calibration mode is followed by a preheating mode.

[0070] The heating system may include a heating element configured to externally heat the aerosol-forming substrate. The heating element may be a resistance heater. The first temperature may be 180 to 230 degrees Celsius.

[0071] Controlling the power may further include increasing the temperature of the heating element from ambient temperature to an initial temperature in preheating mode. The initial temperature may be between 140 and 170 degrees Celsius.

[0072] One or more second temperatures may correspond approximately to the first temperature.

[0073] One or more of the second temperatures may be different from the first temperature.

[0074] Adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period may include lowering the temperature of the heating element from the first temperature.

[0075] One or more second temperatures may be 190-220 degrees Celsius when the aerosol-forming substrate is internally heated. One or more second temperatures may be 180-230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0076] Lowering the temperature of the heating element from a first temperature includes lowering the temperature of the heating element to a second temperature, which is maintained for a second predetermined period.

[0077] Lowering the temperature of the heating element from a first temperature may involve two consecutive temperature steps.

[0078] The temperature in the first temperature step may be lower than the temperature in the second temperature step.

[0079] Adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period may include raising the temperature of the heating element from the first temperature.

[0080] The duration of the second predetermined period may be between 100 and 280 seconds.

[0081] The duration of the third predetermined period may be between 30 and 120 seconds.

[0082] The duration of the first predetermined period may be shorter than at least one of the durations of the second predetermined period and the duration of the third predetermined period.

[0083] The duration of the second predetermined period and the duration of the third predetermined period may be approximately the same.

[0084] Power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, the heating profile defining a method for adjusting the temperature of the heating element during each predetermined period.

[0085] The power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, the heating profile defining a method for adjusting the temperature of the heating element during a predetermined period of second heating.

[0086] The heating profile may be one of several heating profiles, and the heating profile is selected based on identifying one or more characteristics of the aerosol-generating article.

[0087] One or more characteristics of an aerosol-generating article may include the type of aerosol-forming substrate and the type of aerosol-generating article.

[0088] One or more aerosol-forming bodies may contain at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanediate, and dimethyl tetradecanediate.

[0089] The aerosol-forming substrate may be a solid or a gel.

[0090] As used herein in relation 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.

[0091] As used herein in relation to the present invention, the term "gel" is used to describe an aerosol-forming substrate comprising two or more components, one of which is liquid. The gel is predominantly liquid by weight. The gel is a substantially diluted crosslinked system, which, in a steady state, does not exhibit flow, although the liquid phase may still diffuse through the system.

[0092] The aerosol-forming substrate may be a solid film.

[0093] As used herein in relation to the present invention, the term "film" is used to describe a solid aerosol-forming substrate having a thickness substantially less than its width or length.

[0094] As used herein in relation to the present invention, the term "thickness" is used to describe the minimum dimension between substantially parallel, opposing surfaces of a solid aerosol-generating film.

[0095] The aerosol-forming substrate may further contain nicotine. The total nicotine content of the aerosol-forming substrate may be 1 to 2 weight percent.

[0096] As used herein in relation 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 a nicotine base or nicotine salt, the amounts of nicotine listed herein are, respectively, amounts of free base nicotine or amounts of protonated nicotine.

[0097] The aerosol-forming substrate may contain natural nicotine, synthetic nicotine, or a combination of natural and synthetic nicotine.

[0098] The aerosol-forming substrate may contain one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid.

[0099] The aerosol-forming substrate may have a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent.

[0100] As used herein in relation to the present invention, the term “total carboxylic acid content” is used to describe the combined content of all carboxylic acids in the aerosol-forming substrate. For example, if the aerosol-forming substrate contains multiple carboxylic acids consisting of benzoic acid and fumaric acid, the term “total carboxylic acid content” describes the combined content of benzoic acid and fumaric acid in the aerosol-forming substrate.

[0101] The aerosol-forming substrate may contain water.

[0102] The aerosol-forming substrate may have a water content of 5% to 35% by weight.

[0103] Tobacco particles can be homogeneously dispersed within the aerosol-forming substrate.

[0104] Tobacco particles can be as small as 60-80 micrometers.

[0105] The aerosol-forming substrate may contain tobacco particles at a weight percentage of 1 percent or less.

[0106] The aerosol-forming substrate may contain more than 0.5 weight percent and less than 5 weight percent tobacco particles.

[0107] The aerosol-forming substrate may contain a total aerosol-forming material content of more than 35% by weight and less than 40% by weight.

[0108] As used herein, the terms “inhalation” and “smoke inhalation” are interchangeable and intended to mean the act of a user drawing an aerosol into their body through their mouth or nose. Inhalation includes situations in which the aerosol is drawn into the user’s lungs, as well as situations in which the aerosol is drawn into the user’s mouth or nasal cavity before being expelled from the user’s body.

[0109] As used herein, “usage session” refers to the period of use of the device, starting from when the user activates the device. A usage session may include a preheating phase in which the aerosol generator is configured to supply power to a heating system to heat the aerosol-forming substrate and generate aerosols. A usage session may include a calibration phase for calibrating the heating system to more accurately control the temperature of the heating element. A usage session may include a main phase in which the user may inhale the aerosol generated during that time. The main phase may be long enough for multiple inhalations. The main phase may be long enough for three, four, five, or six inhalations. The main phase may be long enough for seven or more inhalations. At the end of a usage phase, the aerosol generator may be configured to stop supplying power to the heating system. The aerosol-forming substrate may be removed from the aerosol generator at the end of a usage session. The aerosol-forming substrate may be replaced in a subsequent usage session. The duration of a usage session, from the start to the end of the usage session, may be at least one, two, three, four, five, or six minutes. Preferably, each session may have a duration of about four and a half minutes.

[0110] As used herein, when referring to an aerosol generator, the terms “upstream” and “forward,” as well as “downstream” and “backward,” are used to describe the relative position of a component or part of a component of an aerosol generator with respect to the direction through which air flows during use of the aerosol generator. The aerosol generator according to the present invention has a proximal end through which aerosols exit the device during use. The proximal end of an aerosol generator 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 an aerosol generating article may also be referred to as the upstream end. Components or parts of a component of an aerosol generator may be described as being upstream or downstream of each other based on their relative position with respect to the airflow path of the aerosol generator.

[0111] When used herein, the terms “upstream” and “front,” and “downstream” and “rear” are used to describe the relative positions of components or parts of components of an aerosol-generating article with respect to the direction in which air flows through the aerosol-generating article during use. The aerosol-generating article according to the present invention has a proximal end through which an aerosol exits the article during use. The proximal end of an aerosol-generating article may also be called the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be called the upstream end. Components or parts of components of an aerosol-generating article may be described as being upstream or downstream of each other based on their relative positions between the proximal end and the distal end of the aerosol-generating article. The front of a component or part of a component of an aerosol-generating article is the part closest to the upstream end of the aerosol-generating article. The rear of a component or part of a component of an aerosol-generating article is the part closest to the downstream end of the aerosol-generating article.

[0112] As used herein, “aerosol cooling element” refers to a component of an aerosol generating article located downstream of an aerosol-forming substrate, so that, during use, the aerosol formed by volatile compounds released from the aerosol-forming substrate passes through the aerosol cooling element 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 formed from bundles of fibers, are not considered aerosol cooling elements. Chambers and cavities within an aerosol generating article are not considered aerosol cooling elements.

[0113] As used herein, the term “mouthpiece” refers to a part of an aerosol generating article, aerosol generating device, or aerosol generating system that is positioned in the user’s mouth for direct inhalation of an aerosol. [Examples]

[0114] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of any of the features described above, for example, one or more features of other embodiments, forms, or aspects described herein.

[0115] Example 1: A method for controlling aerosol generation in an aerosol generating device, the device comprising: a heating chamber configured to at least partially receive an aerosol generating article comprising an aerosol forming substrate, wherein the aerosol forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol forming substrate contains 30 weight percent aerosol forming material; a heating system associated with a heating element configured to heat the aerosol forming substrate; and a power supply for supplying power to the heating system, wherein the method controls the power during heating of the aerosol forming substrate that forms an aerosol to be inhaled by a user to adjust the temperature of the heating element to rise from an initial temperature to a first temperature, the said first temperature is maintained for a first predetermined period, immediately thereafter for a second predetermined period the temperature of the heating element is adjusted to one or more second temperatures, immediately thereafter for a third predetermined period the temperature of the heating element is adjusted to a constant and equal third temperature, the third temperature being approximately the first temperature. Example 2: The method according to Example 1, wherein the heating system is equipped with a heating element, and the heating system is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate. Example 3: The method according to Example 2, wherein the heating element is a resistance heating element, and during use, the heating element engages with the aerosol-forming substrate to heat the aerosol-forming substrate from within. Example 4: The method according to Example 1, 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. Example 5: The method according to one of Examples 2 to 4, wherein the first temperature is 245 to 285 degrees Celsius. Example 6: The method according to one of Examples 1 to 5, further comprising controlling the power to raise the temperature of the heating element from ambient temperature to an initial temperature in preheating mode. Example 7: The method according to Example 6, wherein the initial temperature is 140 to 170 degrees Celsius. Example 8: The method according to Example 6 or 7, wherein the preheating mode has a duration of 10 to 20 seconds. Example 9: The method according to one of Examples 6 to 8, wherein controlling the power further includes calibrating the heating element in a calibration mode, and the calibration mode follows the preheating mode. Example 10: The method according to Example 1, wherein the heating system comprises a heating element, and the heating element is configured to externally heat an aerosol-forming substrate. Example 11: The method according to Example 10, wherein the heating element is a resistance heater. Example 12: The method according to Example 10 or 11, wherein the first temperature is 180-230 degrees Celsius. Example 13: The method according to one of Examples 10-12, further comprising controlling the power to increase the temperature of the heating element from ambient temperature to an initial temperature in preheating mode. Example 14: The method according to Example 13, wherein the initial temperature is 140 to 170 degrees Celsius. Example 15: The method according to any one of Examples 1 to 14, wherein one or more second temperatures are approximately corresponding to the first temperature. Example 16: The method according to one of Examples 1 to 14, wherein one or more second temperatures are different from the first temperature. Example 17: The method according to one of Examples 1 to 14, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period is a reduction in the temperature of the heating element from a first temperature. Example 18: The method according to Example 17, wherein one or more second temperatures are between 190 and 220 degrees Celsius. Example 19: The method according to Example 17 or 18, wherein lowering the temperature of the heating element from a first temperature includes lowering the temperature of the heating element to a second temperature, the said second temperature being maintained for a second predetermined period. Example 20: The method according to Example 17 or 18, wherein lowering the temperature of the heating element from a first temperature includes two consecutive temperature steps. Example 21: The method described in Example 20, wherein the temperature in the first temperature step is lower than the temperature in the second temperature step. Example 22: The method according to one of Examples 1 to 14, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period is a rise in the temperature of the heating element from a first temperature. Example 23: The method according to one of Examples 1 to 22, wherein the duration of the second predetermined period is 100 seconds to 280 seconds. Example 24: The method according to one of Examples 1 to 23, wherein the duration of the third predetermined period is 30 seconds to 120 seconds. Example 25: The method according to one of Examples 1 to 24, wherein the duration of the first predetermined period is shorter than at least one of the durations of the second predetermined period and the duration of the third predetermined period. Example 26: The method according to Example 25, wherein the duration of the second predetermined period and the duration of the third predetermined period are approximately the same. Example 27: The power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, wherein the heating profile defines a method for adjusting the temperature of the heating element during each of predetermined periods, according to one of Examples 1 to 26. Example 28: The power may be controlled during the heating of the aerosol-forming substrate to form an aerosol for inhalation by the user based on a heating profile stored in the controller's memory, wherein the heating profile defines a method for adjusting the temperature of the heating element during a predetermined period of second exothermic activity, according to one of Examples 1 to 26. Example 29: The method according to Example 27 or 28, wherein the heating profile is one of a plurality of heating profiles, and the method further comprises selecting the heating profile based on identifying one or more characteristics of an aerosol-generating article. Example 30: The method according to Example 29, wherein one or more characteristics of the aerosol generator include the type of aerosol-forming substrate and the type of aerosol-generating article. Example 31: The method according to any one of Examples 1 to 30, wherein one or more aerosol-forming bodies contain at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanediate, and dimethyl tetradecanediate. Example 32: The method according to one of Examples 1 to 31, wherein the aerosol-forming substrate is a solid or a gel. Example 33: The method according to one of Examples 1 to 32, wherein the aerosol-forming substrate further contains nicotine. Example 34: The method according to Example 33, wherein the aerosol-forming substrate has a total nicotine content of 1% to 2% by weight. Example 35: The method according to one of Examples 1 to 34, wherein the aerosol-forming substrate further comprises one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid. Example 36: The method according to Example 35, wherein the aerosol-forming substrate has a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent. Example 37: The method according to one of Examples 1 to 36, wherein the aerosol-forming substrate contains water. Example 38: The method according to Example 37, wherein the aerosol-forming substrate has a water content of 5% to 35% by weight. Example 39: The method according to one of Examples 1 to 38, wherein tobacco particles are uniformly distributed within the aerosol-forming substrate. Example 40: The method according to one of Examples 1 to 39, wherein the tobacco particles have a size of 60 to 80 micrometers. Example 41: The method according to one of Examples 1 to 40, wherein the aerosol-forming substrate contains 1 weight percent or less of tobacco particles. Example 42: The method according to one of Examples 1 to 41, wherein the aerosol-forming substrate contains more than 0.5 weight percent tobacco particles and less than 5 weight percent tobacco particles. Example 43: The method according to one of Examples 1 to 42, wherein the aerosol-forming substrate contains an aerosol-forming material content of more than 35% by weight and less than 40% by weight. Example 44: An aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol-forming substrate contains an aerosol-forming material content of 30 weight percent; an aerosol-forming substrate comprising an aerosol-forming substrate comprising a heating chamber configured to receive at least partially the aerosol-generating article; a heating system associated with a heating element configured to heat the aerosol-forming substrate; a power supply for powering the heating system; and a controller configured to control the power while heating the aerosol-forming substrate that forms an aerosol to be inhaled by the user, thereby adjusting the temperature of the heating element to rise from an initial temperature to a first temperature, where the first temperature is maintained for a first predetermined period; immediately after the first predetermined period, adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period; and immediately after the second predetermined period, adjusting the temperature of the heating element to a constant and equal third temperature during a third predetermined period, where the third temperature is configured to correspond approximately to the first temperature. Example 45: The aerosol generating system according to Example 44, wherein the heating system is equipped with a heating element and the heating system is configured to internally heat the aerosol-forming substrate from within the aerosol-forming substrate. Example 46: The aerosol generation system according to Example 45, wherein the heating element is a resistance heating element, and during use, the heating element engages with the aerosol-forming substrate to heat the aerosol-forming substrate from within. Example 47: The aerosol generation system according to Example 44, 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. Example 48: An aerosol generating system according to one of Examples 44-47, wherein the first temperature is 245-285 degrees Celsius. Example 49: An aerosol generating system according to one of Examples 44-48, wherein controlling the power supply in a preheating mode raises the temperature of the heating element from ambient temperature to an initial temperature. Example 50: The aerosol generation system according to Example 49, wherein the initial temperature is 140 to 170 degrees Celsius. Example 51: The aerosol generating system according to Example 49 or 50, wherein the preheating mode has a duration of 10 to 20 seconds. Example 52: An aerosol generating system according to one of Examples 49-51, wherein controlling the power further includes calibrating the heating element in a calibration mode, the calibration mode following the preheating mode. Example 53: The aerosol generating system according to Example 44, comprising a heating element configured to externally heat an aerosol-forming substrate. Example 54: The aerosol generation system according to Example 53, wherein the heating element is a resistance heater. Example 55: The aerosol generating system according to Example 53 or 54, wherein the first temperature is 180-230 degrees Celsius. Example 56: An aerosol generating system according to one of Examples 53-54, wherein controlling the power supply in a preheating mode raises the temperature of the heating element from ambient temperature to an initial temperature. Example 57: The aerosol generating system according to Example 56, wherein the initial temperature is 140 to 170 degrees Celsius. Example 58: An aerosol generating system according to one of Examples 44-57, wherein one or more second temperatures are approximately corresponding to a first temperature. Example 59: An aerosol generating system according to one of Examples 44 to 57, wherein one or more second temperatures are different from the first temperature. Example 60: An aerosol generating system according to one of Examples 44 to 57, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period is a reduction in the temperature of the heating element from a first temperature. Example 61: The aerosol generating system according to Example 60, wherein one or more second temperatures are 190-220 degrees Celsius. Example 62: The aerosol generating system according to Example 60 or 61, wherein lowering the temperature of the heating element from a first temperature includes lowering the temperature of the heating element to a second temperature, the said second temperature being maintained for a second predetermined period of time. Example 63: The aerosol generating system according to Example 60 or 61, wherein the temperature of the heating element is reduced from a first temperature, comprising two consecutive temperature steps. Example 64: The aerosol generating system according to Example 63, wherein the temperature in the first temperature step is lower than the temperature in the second temperature step. Example 65: An aerosol generating system according to one of Examples 44 to 57, wherein adjusting the temperature of the heating element to one or more second temperatures during a second predetermined period is a measure of raising the temperature of the heating element from a first temperature. Example 66: The aerosol generating system according to Examples 44 to 64, wherein the duration of the second predetermined period is 100 seconds to 280 seconds. Example 67: The aerosol generating system according to Examples 44 to 66, wherein the duration of the third predetermined period is 30 seconds to 120 seconds. Example 68: An aerosol generating system according to one of Examples 44 to 67, wherein the duration of the first predetermined period is shorter than at least one of the durations of the second predetermined period and the duration of the third predetermined period. Example 69: The aerosol generating system according to Example 68, wherein the duration of the second predetermined period and the duration of the third predetermined period are approximately the same. Example 70: An aerosol generating system according to one of Examples 44-69, wherein power is controlled during heating of an aerosol-forming substrate to form an aerosol for inhalation by the user based on a heating profile stored in the controller's memory, and the heating profile defines a method for adjusting the temperature of the heating element during each predetermined period. Example 71: An aerosol generating system according to one of Examples 44-69, wherein power is controlled during heating of an aerosol-forming substrate to form an aerosol for inhalation by the user based on a heating profile stored in the controller's memory, and the heating profile defines a method for adjusting the temperature of the heating element during a second predetermined period. Example 72: The aerosol generating system according to Example 70 or 71, wherein the heating profile is one of a plurality of heating profiles, and the heating profile is selected based on identifying one or more characteristics of the aerosol generating article. Example 73: The aerosol generating system according to Example 72, wherein one or more properties of the aerosol generating article include a certain type of aerosol-forming substrate and a certain type of aerosol generating article. Example 74: The aerosol generating system according to Examples 44 to 73, wherein one or more aerosol-forming bodies contain at least one of 1,3-butanediol, glycerin, 1,3-propanediol, propylene glycol, triethylene glycol, glycerol monoacetate, glycerol diacetate, glycerol triacetate, dimethyl dodecanediate, and dimethyl tetradecanediate. Example 75: An aerosol generating system according to one of Examples 44 to 74, wherein the aerosol-forming substrate is a solid or a gel. Example 76: An aerosol generating system according to one of Examples 44 to 75, wherein the aerosol-forming substrate further contains nicotine. Example 77: The aerosol generating system according to Example 76, wherein the aerosol-forming substrate has a total nicotine content of 1% to 2% by weight. Example 78: An aerosol generating system according to one of Examples 44 to 77, wherein the aerosol-forming substrate further comprises one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid. Example 79: The aerosol generating system according to Example 78, wherein the aerosol-forming substrate has a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent. Example 80: An aerosol generating system according to one of Examples 44 to 79, wherein the aerosol-forming substrate contains water. Example 81: The aerosol generating system according to Example 80, wherein the aerosol-forming substrate has a water content of 5% to 35% by weight. Example 82: An aerosol generation system according to one of Examples 44 to 81, wherein tobacco particles are uniformly distributed within an aerosol-forming substrate. Example 83: An aerosol generating system according to one of Examples 44 to 82, wherein the tobacco particles have a size of 60 to 80 micrometers. Example 84: An aerosol generating system according to one of Examples 44 to 83, wherein the aerosol-forming substrate contains 1 weight percent or less of tobacco particles. Example 85: An aerosol generating system according to one of Examples 44 to 83, wherein the aerosol-forming substrate contains more than 0.5 weight percent of tobacco particles and less than 5 weight percent of tobacco particles. Example 86: An aerosol generating system according to one of Examples 44 to 85, wherein the aerosol-forming substrate contains a total aerosol-forming material content of more than 35% by weight and less than 40% by weight.

[0116] Here, we will further describe the examples with reference to the figures. [Brief explanation of the drawing]

[0117] [Figure 1] Figure 1 is a schematic cross-sectional view of an aerosol generating article comprising an aerosol-forming substrate and a susceptor. [Figure 2] Figure 2 is a schematic cross-sectional view of an aerosol generation system comprising the aerosol generating article shown in Figure 1 and an electrically operated aerosol generating device equipped with an inductor. [Figure 3] Figure 3 is a DC current-to-time graph illustrating the remotely detectable change in current that occurs when a susceptor material undergoes a phase transition associated with its Curie point. [Figure 4] Figure 4 is a conductance-to-time graph illustrating the change in conductance corresponding to the change in susceptor temperature during user operation of the aerosol generator. [Figure 5] Figure 5 shows a schematic cross-sectional view of an aerosol generating article containing an aerosol-forming substrate. [Figure 6] Figure 6 shows a schematic cross-sectional view of an aerosol generation system comprising the aerosol generating article shown in Figure 5 and an electrically operated aerosol generating device equipped with a resistance heater for internally heating the aerosol forming substrate from within the aerosol forming substrate. [Figure 7] Figure 7 shows a schematic cross-sectional view of an aerosol generation system comprising the aerosol generating article shown in Figure 5 and an electrically operated aerosol generating device equipped with a resistance heater for externally heating the aerosol forming substrate. [Figure 8] Figure 8 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 6 or Figure 7. [Figure 9] Figure 9 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 10]Figure 10 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 11] Figure 11 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 12] Figure 12 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 13] Figure 13 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 14] Figure 14 is a temperature-time graph illustrating a portion of the heating profile during user operation of the aerosol generator shown in Figure 2, Figure 6, or Figure 7. [Figure 15] Figure 15 is a flowchart illustrating a method for controlling aerosol generation in an aerosol generator. [Modes for carrying out the invention]

[0118] Figure 1 is a schematic cross-sectional view of an aerosol generating article 10 in which the aerosol-forming substrate of the aerosol generating article is inductively heated from within.

[0119] Figure 2 is a schematic cross-sectional view of an aerosol generating system 100, which comprises the aerosol generating article 10 shown in Figure 1 and an electrically operated aerosol generating device 110 equipped with an inductor.

[0120] 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 end or distal end 18 and a downstream end or proximal end 20.

[0121] The proximal section 14 of the aerosol generating article 10 includes 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.

[0122] 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 internal cavity 28 that extends from the upstream end 30 of the first hollow tubular segment 20 to the downstream end 32 of the first hollow tubular segment 20.

[0123] The aerosol cooling element 24 comprises 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 internal cavity 36 extending from the upstream end 38 of the second hollow tubular segment 34 to the downstream end 40 of the second hollow tubular segment 34.

[0124] As shown by the vertical dashed line in Figure 1, the aerosol generating article 10 includes a ventilation zone 60 provided along the second hollow tubular segment 34.

[0125] The mouthpiece element 42 is in the form of a cylindrical plug made of low-density cellulose acetate.

[0126] 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 contains one or more aerosol-forming materials, such as glycerin or propylene glycol. The total aerosol-forming material content of the aerosol-forming substrate may be greater than 30 weight percent. The total aerosol-forming material content of the aerosol-forming substrate may be greater than 35 weight percent and less than 40 weight percent. The aerosol-forming substrate may also contain nicotine. The total nicotine content of the aerosol-forming substrate is 1 to 2 weight percent.

[0127] Additionally, the aerosol-forming substrate may contain tobacco-containing material. Specifically, the aerosol-forming substrate may contain tobacco particles uniformly dispersed within the aerosol-forming substrate. The tobacco particles may have a size of 60 to 80 micrometers. The aerosol-forming substrate may contain 0.1% or more by weight tobacco particles and 10% or less by weight tobacco particles. The aerosol-forming substrate may contain 1% or less by weight tobacco particles. The aerosol-forming substrate may contain more than 0.5% by weight tobacco particles and less than 5% by weight tobacco particles. The amount of nicotine contained in the aerosol-forming substrate can be reduced by the tobacco content. Furthermore, even relatively small amounts of tobacco, such as more than 0.1% by weight, can improve the sensory experience when inhaling the vapor by removing the harshness of the flavor.

[0128] Furthermore, the aerosol-forming substrate may contain water. The aerosol-forming substrate may have a water content of 5% to 35% by weight.

[0129] The aerosol-forming substrate may contain one or more cellulosic agents. The aerosol-forming substrate may contain one or more carboxylic acids. The one or more carboxylic acids may be selected from fumaric acid, maleic acid, and malic acid. The aerosol-forming substrate may have a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent.

[0130] The aerosol-forming substrate may be a solid aerosol-generating film, and the aerosol-generating rod 12 may include an assembly of crumpled paper sheets coated with a solid aerosol-generating film.

[0131] The aerosol generating article 10 includes a heat-generating 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 long axis of the aerosol generating rod 12 from the upstream end to the downstream end. The susceptor 44 is in direct contact with the aerosol forming substrate.

[0132] 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 comprises at least two different materials. The susceptor 44 comprises at least two layers, wherein the first layer of the first susceptor material is arranged in physical contact with the second layer of the second susceptor material. The first and second susceptor materials may each have a Curie temperature. In this case, the Curie temperature of the second susceptor material is lower than that 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.

[0133] The distal section 16 of the aerosol generating article 10 includes an upstream element 46 located immediately upstream of the aerosol generating rod 12.

[0134] The upstream element 46 is in the form of a cylindrical plug of cellulose acetate surrounded by a rigid wrapper.

[0135] The aerosol generating system 100 shown in Figure 2 comprises the aerosol generating article 10 shown in Figure 1 and a handheld, electrically operated aerosol generating device 110.

[0136] The aerosol generator 110 includes a housing 112 that defines a heating chamber 114 configured to receive the distal portion of the aerosol generating article 10.

[0137] The aerosol generator 110 comprises a power source (not shown) and a heating system (not shown). The heating system comprises 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 comprises an induction coil. The controller controls the supply of power from the power source to the induction coil.

[0138] During use, the fluctuating electromagnetic field or alternating electromagnetic field generated by the induction coil of the inductor 116 induces eddy currents in the susceptor 44 within the aerosol generating rod 12 of the aerosol generating article 10, causing the susceptor 44 to heat up. The heat generated in the susceptor 44 is transferred by conduction to the aerosol-forming substrate within the aerosol generating rod 12 of the aerosol generating article 10.

[0139] The user inhales the mouthpiece element 42 of the aerosol generating article 10. When the user inhales 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 are cooled and condensed. The cooled aerosol then passes into the user's mouth through the mouthpiece element 42 of the aerosol generating article 10.

[0140] Figure 3 shows the DC current I drawn from the power source as the temperature of the susceptor 44 (shown by the dashed line) increases. DC The relationship with time is illustrated. More specifically, Figure 3 illustrates the remotely detectable change in DC current that occurs when the susceptor material undergoes a phase transition associated with its Curie point. DC current I drawn from the power source DC This is measured at the input side of the DC / AC converter. For the purposes of this illustration, the voltage V of the power source is used.DC It is sometimes assumed that this remains nearly constant.

[0141] As susceptor 44 is inductively heated, its apparent resistance increases. This increase in resistance is due to the DC current I drawn from the power source. DC This is observed as a decrease in the susceptor 44 temperature, which decreases as the temperature of the susceptor 44 rises at a constant voltage. The high-frequency alternating magnetic field provided by the inductor induces eddy currents very close 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, the resistivity of the second susceptor material, and partly on the depth of the surface thin layer, and the resistivity is consequently temperature-dependent in each material available for the induced eddy currents.

[0142] When the second susceptor material reaches its Curie temperature, it loses its magnetic properties. This causes an increase in the surface thin layer available for eddy currents within the second susceptor material, which in turn causes a decrease in the apparent resistance of the susceptor 44. The result is a detected DC current I DC This is a temporary increase. Subsequently, as the skin thickness of the second susceptor material begins to increase, the resistance begins to decrease. This is seen in Figure 3 as a trough (minimum) of 310.

[0143] As heating continues, the current continues to increase until the second susceptor material reaches its maximum skin thickness, which coincides with the point at which it loses its spontaneously occurring magnetic properties. This point is called the Curie temperature and is shown in Figure 3 as a peak (maximum value) of 320. At this point, the second susceptor material undergoes a phase transition from a ferromagnetic or ferrimagnetic state to a paramagnetic state. At this point, susceptor 160 is at a known temperature (the Curie temperature, which is a temperature specific to the material itself).

[0144] After reaching the Curie temperature, if the induction heating of susceptor 44 continues, the eddy current generated within susceptor 44 will flow against the resistance of susceptor 44, whereby Joule heating within susceptor 44 will continue, and thereby the resistance will increase again (the resistance has a polynomial dependence on temperature, which for most metal susceptor materials can approximate a cubic polynomial dependence for the purposes of the inventors), and the current will begin to decrease again.

[0145] Thus, the second susceptor material undergoes a reversible phase transition between valley 310 and hill 320 shown in FIG. 3 when heated through the (known) temperature range. As can be seen from FIG. 3, the apparent resistance of susceptor 44, and thus the start and end of the reversible phase transition, can be remotely detected by monitoring at least the DC current I DC drawn from the power source. The DC supply voltage V DC is known, but the DC supply voltage V DC may also be monitored in addition to the DC current I DC . Therefore, the apparent resistance of susceptor 44, and thus the start and end of the phase transition, can be remotely detected by monitoring the conductance value (conductance is defined as the ratio to the DC supply voltage V DC of the DC current I DC ) or the resistance value (resistance is defined as the ratio to the DC current ID DC of the DC supply voltage V C ). The DC current I DC , the conductance value, and the resistance value can be referred to as power source parameters.

[0146] As can be seen from FIG. 3, the apparent resistance of susceptor 44 (and correspondingly, the current I DC) may change with the temperature of the susceptor 44 in a strictly monotonic relationship between the start and end of the reversible phase transition, in other words, between the valley 310 and the hill 320. The strictly monotonic relationship allows for a clear determination of the temperature of the susceptor 44 from the determination of the apparent resistance (R) or apparent conductance (1 / R). This is because 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 allows for the determination and control of the temperature of the aerosol-forming substrate.

[0147] The controller adjusts the power supply provided to the heating system based on measurements of power source parameters. The heating system uses DC current I DC The heating system may be equipped with a current sensor (not shown) for measuring the current. The heating system may optionally be supplied with a DC voltage V DC A voltage sensor (not shown) may be provided to measure the current. The current sensor and voltage sensor are located on the input side of the DC / AC converter. DC current I DC , and optionally DC supply voltage V DC AC Power P AC Further supply to the inductor 116 is controlled by a feedback channel to the controller.

[0148] The controller may control the temperature of the susceptor 44 by maintaining the measured power source parameter values ​​at a target value corresponding to the target operating temperature of the susceptor 44. In other words, the controller adjusts the power source parameter values ​​by adjusting the temperature of the susceptor 44 by controlling the power supplied to the heating system.

[0149] 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, the power source parameters measured at the input side of the DC / AC converter during user operation for aerosol generation are 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 (peak 320 in the current plot in Figure 3). The first calibration temperature is a temperature above the susceptor temperature at which the skin thickness of the second susceptor material begins to increase, leading to a temporary decrease in resistance (valley 310 in the current plot in Figure 3). Therefore, the first calibration temperature is a temperature above the temperature at which the second susceptor material is at maximum permeability. 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 the calibration of the susceptor 44, as described in more detail below. The first and second calibration values ​​may be stored as calibration values ​​in the memory of the aerosol generator 110.

[0150] Since the power source parameters will have a polynomial dependence on temperature, they will behave nonlinearly as a function of temperature. However, the first and second calibration values ​​are chosen such that the difference between the first and second calibration values ​​is small, allowing this dependence to be approximated linearly between the first and second calibration values, and such that the first and second calibration values ​​are at the upper end of the operating temperature range. Therefore, to adjust the temperature to the target operating temperature, the power supply parameters are adjusted according to the first and second calibration values ​​through a linear equation.

[0151] For example, if the first and second calibration values ​​are conductance values, the target conductance value G corresponding to the target operating temperature is... R teeth, GR=G Lower +(x×ΔG) It may also be given by the equation, where ΔG is the difference between the first conductance value and the second conductance value, and x is the ratio of ΔG. Therefore, the controller adjusts the power source parameter values ​​based on the power source parameter values ​​measured at the valley 310 during calibration, and the difference between the power source parameter values ​​measured at the hill 320 during calibration and the power source parameter values ​​measured at the valley 310.

[0152] 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 generator 110. For example, the controller may be configured to enter calibration mode to perform the calibration process when the user switches the aerosol generator 110 on. The controller may also be programmed to enter calibration mode each time the user inserts the aerosol generating article 10 into the aerosol generator 110. Therefore, the calibration process is performed during the first heating phase of the aerosol generator, before the main phase in which the user inhales the generated aerosol.

[0153] During the calibration process, the controller controls the DC / AC converter to continuously or continuously supply power to the inductor 116 in order to heat the susceptor 44. The controller controls the current I drawn by the power source. DC , and optionally the power source voltage V DC The power source parameters are monitored by measuring the current. As the susceptor 44 heats up, the measured current decreases until it reaches a trough (first turning point) 310, and then the current I DC It begins to increase. This first inversion point 310 corresponds to a minimum conductance or current value (maximum resistance value). The controller may record the power source parameter value at the first inversion point 310 as the first calibration value.

[0154] The temperature of the susceptor 44 at the first calibration value is the first calibration temperature. As the controller continues to control the power supplied to the inductor 116 by the DC / AC converter, the controller continues to monitor the power supply parameters until it reaches a hill (second turning point) 320. The second turning point corresponds to the maximum current before the measured current begins to decrease (corresponding to the Curie temperature of the second susceptor material). This second turning point 320 corresponds to a maximum conductance or current value (minimum resistance value). The control circuit records the power supply 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 interrupt the supply of power to the inductor 116, resulting in a decrease in the temperature of the susceptor 44 and a corresponding decrease in the measured current.

[0155] Due to the shape of graph 300, the process of continuously heating the susceptor 44 to obtain a first and second calibration value 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 minimum number of iterations of the calibration process, which is more reliable because it allows more time to distribute the heat within the aerosol-forming substrate and the susceptor 44.

[0156] The controller is configured to detect the transition points 310 and 320 by measuring a sequence of power source parameter values. Referring to Figure 3, the measured sequence of power source parameter values ​​forms a curve, where each value is greater than or less than a previous value. The controller is configured to measure a calibration value at the point where the curve begins to flatten. In other words, the controller records a calibration value when the difference between a series of power source parameter values ​​falls below a predetermined threshold.

[0157] To further improve the reliability of the calibration process, the controller may optionally be programmed to perform a preheating process before the calibration process. For example, if the aerosol-forming substrate is particularly dry or under similar conditions, the calibration process may be performed before heat has spread throughout the aerosol-forming substrate, reducing the reliability of the calibration value. If the aerosol-forming substrate is wet, the susceptor 44 will take longer to reach the valley temperature (due to the water content within the aerosol-forming substrate).

[0158] To carry out the preheating process, the controller is configured to continuously supply power to the inductor 116. As described above with respect to Figure 3, the measured current begins to decrease as the temperature of the susceptor 44 rises until it reaches a transition point 310 corresponding to the minimum measured current (conductance). 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 supply of power to the inductor 116. After the predetermined period, the controller controls the DC / AC converter to supply power until it again reaches the transition point 310 corresponding to the minimum measured current. At this point, the controller controls the DC / AC converter to again interrupt the supply 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 calibration process lasts for 10 to 20 seconds. If the aerosol-forming substrate is dry, the first current minimum of the preheating process is reached within a predetermined period, and power interruptions are repeated until the end of the predetermined period. If the aerosol-forming substrate has a higher moisture content, the first current minimum of the preheating process 410 is reached towards the end of the predetermined period. Therefore, performing the preheating process for a predetermined duration ensures that there is sufficient time for the aerosol-forming substrate to reach its minimum operating temperature in order to be continuously powered and ready to reach the first maximum value, regardless of the physical state of the aerosol-forming substrate. This allows for calibration as early as possible without still bearing the risk that the aerosol-forming substrate has not reached the first calibration temperature beforehand.

[0159] Specifically, aerosol-forming substrates with a higher aerosol-forming content (e.g., higher than 30 weight percent) and a higher water content (e.g., higher than 5 weight percent) will have higher thermal inertia. Therefore, the preheating process ensures that the minimum operating temperature is reached before calibration.

[0160] The preheating process may be performed in response to user input, for example, the reception of user activation of the aerosol generator 110. In addition, or otherwise, the control circuit may be configured to detect the presence of the aerosol generating article 10 in the aerosol generator 110, and the preheating process may be performed in response to the detection of the presence of the aerosol generating article 10 in the heating chamber of the aerosol generator 110.

[0161] Figure 4 is a graph of conductance against time showing the heating profile of the susceptor 44. The graph shows five stages of the heating profile: a preheating process performed during preheating mode 410, a calibration process performed during calibration mode 420, and the main heating phase, which heats the aerosol-forming substrate to produce an aerosol for the user to inhale. The main heating phase is illustrated as including heating steps having predetermined periods 430, 440, and 450, respectively. Although Figure 4 is illustrated as a graph of conductance against time, it is 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 described above.

[0162] Once the calibration process 420 is complete, the controller is configured to interrupt the supply of power to the heating system, allowing the susceptor to cool to its initial temperature. When it is detected that the susceptor temperature is at the initial temperature, or after the susceptor temperature has been at the initial temperature for a predetermined period, the controller is configured to control the power supplied to the heating system to increase the temperature of the susceptor 44 from the initial temperature to a first temperature. Specifically, the controller adjusts the conductance to control the power supplied to the heating system to correspond to a first operating temperature of the susceptor 44 for a first predetermined period. In one embodiment, the conductance during the first heating step 430 is 0.75 × ΔG, or in other words, 75 percent of the difference in measured conductance between the hill 320 and the valley 310.

[0163] The first operating temperature is chosen so that the desired volatile compounds vaporize from the substrate, but undesirable compounds that vaporize or are generated at higher temperatures are not released. Furthermore, heating the susceptor 44 to its maximum operating temperature immediately after the calibration process 420 improves the amount of the desired volatile compounds vaporized, thereby providing improved delivery from the initial smoke to the user. The first operating temperature of the susceptor 44 may also be its maximum operating temperature.

[0164] Figure 5 is a schematic cross-sectional view of the aerosol generating article 500, and

[0165] Figure 6 is a schematic cross-sectional view of an aerosol generating system 600, which comprises the aerosol generating article 500 shown in Figure 5, and an electrically operated aerosol generating device 610 equipped with a resistance heater configured to heat the aerosol generating article 500 from within.

[0166] The aerosol generating article 500 has generally the same structure as the aerosol generating article 10 described above with respect to Figure 1, where similar elements are indicated by the same reference numerals. In particular, the aerosol generating article comprises the same aerosol-forming substrate as described above with respect to Figure 1. However, it should be noted that the aerosol generating article 500 does not have a susceptor 44. In addition, the aerosol generating article 500 does not have an upstream element 46.

[0167] The aerosol generator 610 comprises a heating chamber 630 for receiving the aerosol generating article 500. The heating element 620 is located within the heating chamber and is positioned to engage with the distal end 18 of the aerosol generating article 500. The heating element 620 is an electrically resistive heating element shaped into the form of a blade terminating at a single point. The heating element 620 may be formed from a ceramic substrate having one or more resistive heating tracks, which are formed from platinum or another suitable material and are positioned 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, e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wires or heating plates. Optionally, the heating element 620 may be placed in 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 exemplary devices, the metal may be formed as a track on a suitable insulating material such as ceramic material, and then coated with another insulating material such as glass. The heater thus formed may be used for both heating a heating element in operation and monitoring its temperature.

[0168] When the aerosol generating article 500 is pushed onto the tip of the heating element 620 by applying force to the aerosol generating article 500, the heating element 620 penetrates into the aerosol forming substrate of the aerosol generating rod 12. Further penetration is prevented because the distal end 18 of the aerosol generating article 500 abuts against the end wall 640 of the heating chamber 630, which acts as a stopper.

[0169] When the aerosol generating article 500 is properly engaged with the aerosol generating device 610, the heating element 620 is in contact with the aerosol forming substrate and positioned within the aerosol forming substrate. The heating element 620 heats the aerosol forming substrate by conduction.

[0170] The aerosol generator 610 includes a power source (not shown) and a heating system (not shown) electrically connected 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 supply power to the heating system in order to heat the heating element 620.

[0171] 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. This temperature indication is used to adjust the current supplied to the heating element 620 in order to maintain it near the target temperature. In other words, the controller adjusts the temperature of the heating element by adjusting the current supplied to the heating element 620.

[0172] This scheme relies on three or more temperature calibration points where the resistance of the heating element 620 is measured. For temperatures between the calibration points, the resistance value is interpolated from the value at the calibration point. The calibration point temperatures are selected 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, or the calibration points may be stored in the controller's memory.

[0173] When the heating element 620 is heated, the aerosol-forming substrate is heated, and volatile substances are formed. When the user inhales the proximal end 20 of the aerosol-generating article 500, air is drawn into the aerosol-generating article 500, and the volatile substances condense to form an inhalable aerosol. This aerosol passes through the proximal end 20 of the aerosol-generating article 500 and enters the user's mouth.

[0174] Figure 7 is a schematic cross-sectional view of an aerosol generating system comprising an aerosol generating device 700 and an aerosol generating article 500 in which an 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. The aerosol generating article 500 in Figure 5 does not have an upstream element 46, but the upstream element 46 may be present in the embodiment of Figure 7.

[0175] The aerosol generator 700 includes a heating chamber 710 for receiving the aerosol generating article 500. The heating chamber 710 is formed from a stainless steel tube 730 and also has a base 750 at its upstream end.

[0176] 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 pipe 730 are configured such that, when the aerosol generating article 500 is received within the heating chamber 710, the proximal end 20 of the aerosol generating article 500, which the user may inhale during use, protrudes outside the heating chamber 710 and outside the aerosol generating device 700.

[0177] The aerosol generator 700 further comprises a heating system including a heating element 745. The heating element 745 is bent around the upstream end of the stainless steel pipe 730, enclosing the upstream end. The portion of the stainless steel pipe 730 enclosed by the heating element 745 corresponds to the portion of the heating chamber 710 into which the aerosol-forming substrate 725 of the aerosol-generating article 500 is received when the aerosol-generating article 500 is received into the heating chamber 710.

[0178] The heating system further includes 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.

[0179] 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 shrinkable layer. The temperature sensor 740 is positioned between the second polyimide layer and the heat shrinkable layer. The temperature sensor 740 is provided with a connecting wire for connecting the temperature sensor 740 to the controller 755.

[0180] The first adhesive layer is used to bond the heating element 745 to the stainless steel tube 730. Sandwiching the heater track between the first polyimide layer and the second polyimide layer provides a means of supporting the heater track in place and also provides electrical insulation between the heater track and other components of the aerosol generator 700, particularly the stainless steel tube 730. Polyimide is advantageously flexible, electrically insulating, and can withstand the normal operating temperatures of the aerosol generator, specifically the heater track, during use. The heater track is a continuous conductive track of stainless steel deposited on top of either the first or second polyimide layer during manufacturing. The heater track is configured to heat when an electric current passes through it.

[0181] In other words, the heating element 745 is a resistance heating element 745. The heater track has a resistance of 1.1 ohms at room temperature. The second adhesive layer holds the first polyimide layer and the second polyimide layer together, and they keep the heater track in place.

[0182] The heat-shrinkable layer contains a material that can withstand the normal operating temperature of the aerosol generator, specifically the heater track, during use.

[0183] The aerosol generator 700 further includes 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 Figure 7. The power source 775 is configured to supply power to the heating element 745 and is also connected to a connector on the heater track. Heating of the heating element 745 by the power source 775 is controlled by the controller 755.

[0184] The airflow channel 765 extends from the air intake 760 of the aerosol generator 700. Upstream of the heating chamber 710, the airflow channel 765 is mainly defined by the airflow channel wall 770. Downstream of the airflow channel wall 770, the airflow channel 765 passes through an air intake defined within 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 into the heating chamber 710, the airflow channel 765 passes through the aerosol generating article 500 and then extends through the mouthpiece 42.

[0185] During use of the aerosol generating system, the aerosol generating article 500 is inserted into the heating chamber 710 by the user of the system. The user then activates the device, which may be done, for example, by pressing a button or by inhaling through the mouthpiece 42 of the aerosol generating article 500, which is detected by a smoke extraction sensor (not shown in Figure 7).

[0186] Following startup, the controller 755 is configured to control the supply of power from the power source 775 to the heating element 745 to heat the heating track.

[0187] 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 generated vapor being released into the air drawn into the aerosol-generating article 500 via the airflow channel 765. The vapor is then cooled and condenses into an aerosol. Therefore, when the user inhales through the mouthpiece 42, the generated aerosol is drawn through the aerosol-generating article 500 and inhaled by the user.

[0188] The controller 755 controls the heating based on the temperature signal received from the temperature sensor 740. The controller 755 is configured to control the power supplied to the heating element 745 to adjust the temperature of the heating element 745 based on the temperature measured by the temperature sensor.

[0189] Alternatively, the controller 755 may measure the electrical resistance of the heating element 745 to obtain a temperature indication of the heating element 745 in the same manner as the controller of the aerosol generator 610 described with respect to Figure 6. In this scenario, the temperature sensor 740 is an optional component of the aerosol generator 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.

[0190] Figure 8 is a graph of the heating element temperature against time, showing a portion of the heating profile for an aerosol generator using resistance heating as described in relation to Figures 6 and 7. During phase 810, the heating element is at its initial temperature. Phase 810 may also be a preheating phase in which the controller is programmed to preheat the heating element to a predetermined initial temperature for a predetermined duration.

[0191] The preheating phase ensures that the duration of the preheating phase is sufficient to reach the minimum operating temperature of the aerosol-forming substrate, so that it can be supplied with continuous power to generate enough aerosol to be inhaled by the user, regardless of the physical state of the aerosol-forming substrate (e.g., dry or wet), and so that it can reach the first operating temperature as quickly as possible.

[0192] Specifically, aerosol-forming substrates containing a higher aerosol-forming material content (e.g., higher than 30 weight percent) and a higher water content (e.g., higher than 5 weight percent) will have higher thermal inertia. Therefore, in the case of aerosol-forming substrates with a higher water content, the preheating process ensures that the minimum operating temperature is reached before the main heating phase. The duration of the preheating mode is 10 to 20 seconds, preferably 11 seconds.

[0193] After the preheating phase, the controller is configured to enter a first heating step for a predetermined period 820 of the first main phase of heating. The first heating step may also be entered in response to a timer indicating that a predetermined duration of the preheating phase 810 has elapsed, user activation of the aerosol generator, or detection of user smoke extraction. During the first heating step 820, the controller rapidly raises the temperature of the heating element from the initial temperature to the first temperature.

[0194] The first temperature is selected such that the desired volatile compound vaporizes from the substrate, but undesirable compounds that vaporize or are generated at higher temperatures are not released. Furthermore, rapidly heating the heating element to the first temperature improves the amount of the desired volatile compound vaporized, thereby providing improved delivery from the first fumes to the user. The first temperature may also be the maximum operating temperature of the heating element.

[0195] During phases 820, 830, and 840, the aerosol generator is configured to generate aerosols for inhalation by the user, and the controller is configured to control the power supplied to the heating element in order to adjust the temperature of the heating element according to the heating profile.

[0196] One or more heating profiles may be stored in the memory of the controller, as described with respect to Figures 1, 2, 6, and 7. The controller may be configured to select a heating profile during user operation of the aerosol generating apparatus. For example, the aerosol generating apparatus may include means for identifying an aerosol generating article, an aerosol forming substrate, or their properties, and select a heating profile based on the results of the identification.

[0197] Figures 9–14 are graphs of the heating element temperature against time, illustrating an exemplary heating profile of the heating element during the main phase of heating the aerosol-forming substrate for user inhalation. The illustrated heating profile defines three temperature steps of a given duration during the main phase of heating. However, it should be understood that the heating profile may include more than three temperature steps.

[0198] Each of the heating profiles in Figures 9-14 shows shaded areas 910, 1010, 1110, 1210, 1310, and 1410. These shaded areas correspond to the calibration phase and optional preheating phase of an aerosol generator with an induction heating system (Figure 2), or the preheating phase of an aerosol generator with a resistance heating system (Figures 6 and 7). The controller may be configured to enter the main heating phase in response to user activation of the aerosol generator or detection of smoke extraction by the user.

[0199] The heating profiles in Figures 9 to 14 show that the temperature of the heating element rises from an initial temperature (not shown) to a first temperature during a first predetermined period of 920, 1020, 1120, 1220, 1320, and 1420. The temperature remains constant at the first temperature for the duration of the first period. The initial temperature is higher than the 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 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 at which the heating element 44 cools may be the initial temperature. In the case of resistance heating, the initial temperature may be the preheating temperature of the heating elements 620 and 745.

[0200] The first temperature may be 245-285 degrees Celsius when the aerosol-forming substrate is internally heated. The first temperature may be 180-230 degrees Celsius when the aerosol-forming substrate is externally heated. As discussed above, the heating element is heated to the first temperature over a first predetermined period of 920, 1020, 1120, 1220, 1320, and 1420, over which the thermal inertia of the aerosol-forming substrate is overcome, and the amount of vaporized desired volatile compounds in the aerosol inhaled by the user, such as nicotine and the aerosol-forming substrate, is improved from the first inhalation.

[0201] After the first predetermined period of 920, 1020, 1120, 1220, 1320, 1420, the controller adjusts the temperature of the heating element to one or more second temperatures during the second predetermined period of 930, 1030, 1130, 1230, 1330, 1430. One or more second temperatures may be 190-220 degrees Celsius when the aerosol-forming substrate is internally heated. One or more second temperatures may be 180-230 degrees Celsius when the aerosol-forming substrate is externally heated.

[0202] During the second predetermined period of 930, 1030, 1130, 1230, 1330, and 1340, the controller may adjust the temperature of the heating element to approximately correspond to the first temperature, as shown in Figure 9.

[0203] Over the second predetermined period 930, 1030, 1130, 1230, 1330, and 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 predetermined period 920, 1020, 1120, 1220, 1320, and 1420, the heat will have diffused throughout the aerosol-forming substrate. Therefore, lowering the temperature of the heating element during the second predetermined period 930, 1030, 1130, 1230, 1330, and 1430 makes it possible to maintain the same amount of vaporized desired volatile compounds in the aerosol inhaled by the user as during the first predetermined period 920, 1020, 1120, 1220, 1320, and 1420, thereby providing the user with the same sensory experience.

[0204] Alternatively, over a second predetermined period of 930, 1030, 1130, 1230, 1330, and 1340, the controller may adjust the temperature of the heating element to be higher than the first temperature, as shown in Figure 14.

[0205] During the second predetermined periods 930, 1030, 1130, 1230, 1330, and 1430, the controller may adjust the temperature of the heating element to a second temperature over the duration of the second predetermined period, as shown in Figures 9, 10, and 14. Alternatively, during the second predetermined period, the controller may adjust the temperature of the heating element in multiple consecutive temperature steps. For example, Figure 11 shows two temperature steps with 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.

[0206] Over a third predetermined period of 940, 1040, 1140, 1240, 1340, and 1440, the controller is configured to adjust the temperature of the heating element to the third temperature. The temperature of the heating element remains constant at the third temperature for the predetermined duration of the third period. As shown in Figures 9 to 14, the third temperature approximately corresponds to the first temperature. At this stage of the usage session, the desired volatile compounds in the aerosol-forming substrate are depleted. Therefore, by raising the temperature of the heating element to approximately the first temperature, the amount of vaporized desired volatile compounds in the aerosol inhaled by the user can be maintained to match the amount vaporized during the first and second predetermined periods.

[0207] Each of the predetermined periods may be of equal length. The first predetermined period may be shorter than the 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 the 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 to 14. The first and third predetermined periods may have a duration, for example, as shown in Figure 13.

[0208] The length of the first predetermined period may be between 40 and 150 seconds. The length of the second predetermined period may be between 100 and 280 seconds. The length of the third predetermined period may be between 30 and 120 seconds.

[0209] The length of the first predetermined period is selected so that the aerosol-forming substrate can provide good delivery of the desired volatile compound within the aerosol. The first predetermined period is at least shorter than the second predetermined period to ensure good aerosol delivery to the user while ensuring consistency of the user experience throughout the entire usage session.

[0210] A second predetermined period length that is at least longer than the first predetermined period provides improved control over the amount of desired volatile compounds vaporized in the aerosol inhaled by the user, particularly when the second temperature is lower than the first temperature, thereby providing a consistent user experience for as long as possible throughout the entire usage session.

[0211] Figure 15 is a flowchart illustrating a method for controlling aerosol generation in one of the aerosol generators by heating a heating article inserted into the heating chamber of the aerosol generator, as described above.

[0212] The method begins in step 1510 when the user activates the heating of the heating element, as described above. For example, the user may start heating the heating element by pressing one or more buttons on the aerosol generator. Additionally, or by other means, the user may insert an aerosol generating article into the heating chamber of the aerosol generator in order to heat the heating element.

[0213] Next, the method proceeds to step 1520, where the controller controls the power supplied to the heating system to increase the temperature of the heating element from the ambient temperature to the initial temperature. During step 1520, the controller is in preheating mode and maintains the temperature of the heating element at the initial temperature for a predetermined period of time.

[0214] When the aerosol generator heats the heating element by induction (aerosol generator in Figure 2), after the preheating mode, a calibration process follows in step 1530 to obtain a first calibration value and a second calibration value. The controller uses the first and second calibration values ​​to adjust the susceptor temperature as described above.

[0215] In step 1540, following step 1520 for aerosol generators using resistance heating, and following step 1530 for aerosol generators using induction heating, the controller enters the main phase of heating. Specifically, the controller adjusts the temperature of the heating element to increase the temperature from the initial temperature to a first temperature. The first temperature is maintained for a first predetermined period.

[0216] At the end of the first predetermined period, the controller adjusts the temperature of the heating element to a second temperature (step 1550). The second temperature may be maintained for a second predetermined period. Alternatively, the second temperature may be the first step of a plurality of temperature steps, each having a predetermined duration, where the sum of the predetermined durations of each temperature step is the duration of the second predetermined period. The second temperature may be lower than the first temperature, approximately equal to the first temperature, or higher than the first temperature.

[0217] At the end of the second predetermined period, the controller adjusts the temperature of the heating element to a third temperature (step 1560). The third temperature is maintained for the duration of the third predetermined period. The third temperature is approximately equal to the first temperature and remains constant for the duration of the third predetermined period.

[0218] It should be understood that the figures are for illustrative purposes only and are not shown in proportion to actual size. Furthermore, naturally, the aerosol generating articles and aerosol generating devices shown in the figures and described in detail above may have additional elements beyond those considered. Similarly, the aerosol generating articles or aerosol generating devices according to the embodiments considered herein may have fewer elements. Moreover, it will be apparent to those skilled in the art that the various dimensions of the elements considered in relation to the various embodiments discussed herein are merely illustrative, and that appropriate alternative dimensions may be chosen for the various elements.

[0219] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., are understood to be modified in all cases by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 10%. In this context, the number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that the number A modifies. In some cases used in the appended claims, the number A may deviate by the percentages listed above, provided that the amount of deviation of A does not substantially affect the basic and novel characteristics of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein. Furthermore, in the context of this invention, the expression that number A "approximately corresponds" to number B is understood to mean that number A is equal to B ± 10% of B.

Claims

1. A method for controlling aerosol generation in an aerosol generating system, wherein the system comprises an aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate is a cellulosic substrate containing more than 0.1 weight percent tobacco particles and 10 weight percent or less tobacco particles, and the aerosol-forming substrate contains more than 30 weight percent of the aerosol-forming material; 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 supply for supplying power to the heating system, wherein the method heats the aerosol-forming substrate to form an aerosol for inhalation by a user, The temperature of the heating element is adjusted to raise the temperature from the initial temperature to a first temperature, and in this process, the first temperature is maintained for a predetermined first period of time. Immediately after the first predetermined period, during the second predetermined period, the temperature of the heating element is adjusted to one or more second temperatures. A method comprising controlling the power such that, immediately after the second predetermined period, the temperature of the heating element is adjusted to a constant and equal temperature to the third predetermined temperature during the third predetermined period, wherein the third temperature is substantially equal to the first temperature.

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 or 2, further comprising controlling the power to raise the temperature of the heating element from the ambient temperature to the initial temperature in the preheating mode.

4. The method according to claim 3, wherein controlling the power further includes calibrating the heating element in a calibration mode, the calibration mode following the preheating mode.

5. The method according to one of claims 1 to 4, 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.

6. The method according to claim 5, wherein lowering the temperature of the heating element from the first temperature includes lowering the temperature of the heating element to a second temperature, and the second temperature is maintained for a second predetermined period of time.

7. The method according to one of claims 1 to 6, wherein the aerosol-forming substrate further contains nicotine, and the aerosol-forming substrate has a total nicotine content of 1 to 2 percent by weight.

8. Aerosol generation system, An aerosol generating article comprising an aerosol-forming substrate, wherein the aerosol-forming substrate contains more than 0.1 weight percent of tobacco particles and 10 weight percent or less of tobacco particles, and the aerosol-forming substrate is a cellulose-based substrate containing more than 30 weight percent of aerosol-forming material, 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 supply for providing power to the aforementioned heating system, A controller, wherein during heating of the aerosol-forming substrate that forms an aerosol for inhalation by the user, The temperature of the heating element is adjusted to rise from the initial temperature to the first temperature, and in this process, the first temperature is maintained for a predetermined period of time. Immediately after the first predetermined period, during the second predetermined period, the temperature of the heating element is adjusted to one or more second temperatures. An aerosol generating system comprising: a controller that adjusts the temperature of the heating element to a constant and equal temperature to the third temperature during a third predetermined period immediately following the second predetermined period, and controls the power so that the third temperature substantially corresponds to the first temperature.

9. The aerosol generating system according to claim 8, wherein one or more second temperatures substantially correspond to the first temperature.

10. The aerosol generating system according to claim 8 or 9, wherein the power is controlled during heating of the aerosol-forming substrate to form an aerosol for user inhalation based on a heating profile stored in the controller's memory, and the heating profile defines a method for adjusting the temperature of the heating element during each predetermined period.

11. The aerosol generating system according to claim 10, wherein the heating profile is one of a plurality of heating profiles, and the heating profile is selected based on identifying one or more characteristics of the aerosol generating article.

12. The system according to any one of claims 8 to 11, wherein the aerosol-forming substrate further contains nicotine, and the aerosol-forming substrate has a total nicotine content of 1 to 2 weight percent.

13. The aerosol generating system according to any one of claims 8 to 12, wherein the aerosol-forming substrate further comprises one or more carboxylic acids selected from fumaric acid, maleic acid, and malic acid, and the aerosol-forming substrate has a total cellulose content of at least 35 weight percent and a total carboxylic acid content of 1 to 2 weight percent.

14. The aerosol generating system according to any one of claims 8 to 13, wherein the aerosol-forming substrate contains water, and the aerosol-forming substrate has a water content of 5% by weight to 35% by weight.

15. The aerosol generating system according to any one of claims 8 to 14, wherein the tobacco particles are uniformly dispersed in the aerosol forming substrate, and the tobacco particles have a size of 60 to 80 micrometers.

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