Aerosol generation system and related methods

Abstract

A method for controlling an aerosol generating system is provided. The aerosol generating system comprises internal heaters (114, 164, 264, 1914) configured to heat the aerosol-forming substrate (104) from inside the aerosol-forming substrate, and external heaters (24, 224, 240, 1924) configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate. The method includes raising the temperature of the internal heaters to at least the minimum preheating temperature of the internal heaters during a preheating stage, lowering the temperature of the internal heaters to a temperature lower than the minimum preheating temperature of the internal heaters during a cooling stage following the preheating stage, and raising the temperature of one or both of the internal heaters and the external heaters during a first stage following the cooling stage.

Description

[Technical Field]

[0001] This disclosure relates to an aerosol generation system and a method for controlling an aerosol generation system. [Background technology]

[0002] Some known aerosol generating systems comprise an aerosol generating device and an aerosol generating article containing an aerosol-forming substrate. During use, the aerosol generating device heats the aerosol-forming substrate of the aerosol generating article to form an aerosol.

[0003] Some known aerosol generators are equipped with an internal heater to heat the aerosol-forming substrate from within. However, using the internal heater to sufficiently heat the outer portion of the aerosol-forming substrate to form an aerosol may require heating the internal heater to a sufficiently high temperature, which carries the risk of overheating the internal heater or scorching the inner portion of the aerosol-forming substrate that is close to the internal heater. Therefore, when using an internal heater, the outer portion of the aerosol-forming substrate furthest from the internal heater is usually not heated to a temperature high enough to form an aerosol during use. This means that the outer portion of the aerosol-forming substrate is usually wasted.

[0004] Some known aerosol generators are equipped with an external heater to heat the aerosol-forming substrate from the outside. However, using an external heater to sufficiently heat the inner portion of the aerosol-forming substrate to form an aerosol may require the external heater to be heated to a sufficiently high temperature, which carries the risk of overheating the external heater or scorching the outer portion of the aerosol-forming substrate that is close to the heater. Therefore, when using an external heater, the inner portion of the aerosol-forming substrate furthest from the external heater is usually not heated to a temperature high enough to form an aerosol during use. This means that the inner portion of the aerosol-forming substrate is usually wasted.

[0005] The object of the present invention is to provide an improved aerosol generation system and an improved method for controlling the aerosol generation system. [Overview of the project]

[0006] The present disclosure provides a method for controlling an aerosol generating system. The aerosol generating system may include an internal heater. The internal heater may be configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate. The aerosol generating system may include an external heater. The external heater may be configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate. The method may include controlling the power supply to one or both of the internal heater and the external heater during a plurality of steps, the power supply may differ in at least two of the steps, or in each step.

[0007] Accordingly, according to a first aspect of the present invention, a method for controlling an aerosol generating system is provided. The aerosol generating system comprises an internal heater configured to heat an aerosol-forming substrate from inside the aerosol-forming substrate and an external heater configured to heat an aerosol-forming substrate from outside the aerosol-forming substrate. The method comprises controlling the power supply to one or both of the internal heater and the external heater during a plurality of steps, wherein the power supply differs in at least two of the plurality of steps, or in each step.

[0008] The present disclosure provides an aerosol generating system. The aerosol generating system may include an internal heater. The internal heater may be configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate. The aerosol generating system may include an external heater. The external heater may be configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate. The aerosol generating system may include a controller. The controller may be configured to control the power supply to one or both of the internal heater and the external heater during a plurality of stages, and the power supply may differ in at least two of the plurality of stages, or in each stage.

[0009] Accordingly, according to a second aspect of the present disclosure, an aerosol generating system is provided comprising an internal heater configured to heat an aerosol-forming substrate from inside the aerosol-forming substrate, an external heater configured to heat an aerosol-forming substrate from outside the aerosol-forming substrate, and a controller. The controller is configured to control the power supply to one or both of the internal heater and the external heater during a plurality of stages, wherein the power supply differs in at least two of the plurality of stages, or in each stage.

[0010] One or both of the first and second embodiments of the aerosol generating system may comprise an aerosol generating device and an aerosol generating article containing an aerosol-forming substrate. The aerosol generating device may include an external heater. The aerosol generating device or article may include an internal heater.

[0011] The present disclosure provides an aerosol generator for use as part of an aerosol generating system. The aerosol generating system may comprise an aerosol generator and an aerosol generating article comprising an aerosol-forming substrate. The aerosol generating system, for example, the apparatus or article of the system, may include an internal heater. The internal heater may be configured to heat the aerosol-forming substrate from the inside. The aerosol generator may include an external heater. The external heater may be configured to heat the aerosol-forming substrate from the outside. The aerosol generator may include a controller. The controller may be configured to control the power supply to one or both of the internal heater and the external heater during a plurality of stages, the power supply may differ in at least two of the plurality of stages, or in each stage.

[0012] Accordingly, according to a third aspect of the present disclosure, an aerosol generator is provided for use as part of an aerosol generating system. The aerosol generating system comprises an aerosol generator and an aerosol generating article including an aerosol-forming substrate. The aerosol generating system, for example, the apparatus or article of the system, includes an internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate. The aerosol generator includes an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate and a controller. The controller is configured to control the power supply to one or both of the internal heater and the external heater during a plurality of stages, the power supply being different in at least two of the plurality of stages or in each stage.

[0013] Advantageously, the presence of both internal and external heaters allows for heating of the aerosol-forming substrate from both the inside and outside. This reduces the proportion of aerosol-forming substrate that does not reach a temperature high enough to form aerosols during use, thereby reducing waste.

[0014] Advantageously, the power supply can be different at at least two of the plurality of stages or at each stage, enabling adjustment of the temperature profiles of the internal and external heaters between various stages of the usage session. As an example, the power supply during the preheating stage enables rapid heating of the aerosol-forming substrate, making it possible to shorten the time required for the first puff in the system.

[0015] The features of any one aspect may be applicable to any other aspect. For example, the device referred to in the second aspect may be the device of the third aspect. The system referred to in the third aspect may be the system of the second aspect. The controller of the second or third aspect may be configured to perform the method according to the first aspect. The controller may be configured to perform any of the steps of the methods described below.

[0016] Any of the features described below can be applied to one, two, or all of the first, second, and third aspects of the present disclosure.

[0017] References to systems, devices, articles, and substrates herein may each refer to an aerosol generation system, an aerosol generation device, an aerosol generation article, and an aerosol-forming substrate, respectively.

[0018] The apparatus may engage with an article and be configured, for example, to receive at least a portion of the article. The apparatus may include a housing. The apparatus may include a chamber. The housing may define the chamber. The chamber may be configured to receive at least a portion of the article. The chamber may have a base. The chamber may have an open end. The open end may face the base. The apparatus may be configured to receive at least a portion of the article into the chamber through the open end of the chamber. If the article is at least partially received into the chamber, the aerosol-forming substrate of the article may be fully received into the chamber. That is, if the article is at least partially received into the chamber, the entire aerosol-forming substrate of the article may be in the chamber.

[0019] The device may include a controller. A system, for example, a device in the system, may include at least one power supply. Hereafter, references to “power supply” or “that power supply” shall be deemed to refer to at least one power supply. References to power supply in this specification may refer to power supply from a power supply. Controlling the power supply to an internal or external heater may include, or may include, controlling the power supply, for example, controlling one or both of the current and voltage from at least one power supply to the internal or external heater. References to raising or lowering the temperature of an internal heater in this specification may be a result of controlling the power supply to one or both of the internal and external heaters. References to raising or lowering the temperature of an external heater in this specification may be a result of controlling the power supply to the external heater.

[0020] In particular, as will be described in more detail later, the external heater may be or include an inductor, such as an inductor coil. In this case, the terms “controlling the power supply to the external heater” and “controlling the power supply to the inductor” are used interchangeably. Similarly, as will be described in more detail later, the internal heater may be or include a susceptor. In this case, the terms “controlling the power supply to the internal heater” and “controlling the power supply to the susceptor” are used interchangeably. This interchangeable terminology applies to the descriptions and embodiments listed below. Furthermore, when the external heater is an inductor and the internal heater is a susceptor, the heating of the internal heater may be controlled by controlling the power supply to the external heater. Controlling the power supply to the internal heater may include inductive power transfer from the inductor to the internal heater.

[0021] The external heater may be, or may include, an electrical resistance heater, also known as a Joule effect heater. The external heater may be, or may include, an inductor, such as an inductor coil. The internal heater may be an electrical resistance heater. The internal heater may be, or may include, a susceptor for induction heating. Therefore, there are numerous options for the internal and external heaters. The following five paragraphs briefly examine some of the more complete options.

[0022] In the first configuration, the device comprises an internal heater and an external heater, the internal heater being or including a susceptor, and the external heater being or including an inductor, such as an inductor coil. In such embodiments, the inductor can function as an external heater by supplying power to it to resistively heat it, and the susceptor can function as an internal heater by supplying power to it to inductively heat it. Advantageously, since the inductor can both inductively heat the internal heater and resistively heat and function as an external heater, it is possible to heat the aerosol-forming substrate from both the inside and outside in a less complex configuration than a typical induction heating configuration.

[0023] In the second configuration, the device comprises an external heater, the article comprises an internal heater, the internal heater is or includes a susceptor, and the external heater is or includes an inductor, such as an inductor coil. Advantageously, since the inductor can both inductively heat the internal heater and resistively heat it to function as an external heater, it is possible to heat the aerosol-forming substrate from both the inside and outside in a less complex configuration than a typical induction heating configuration.

[0024] In the third configuration, the device is equipped with an internal heater, the device is equipped with an external heater, the internal heater is an electrical resistance heater, and the external heater is an electrical resistance heater.

[0025] In the fourth configuration, the device includes an internal heater, an external heater, and an inductor distinct from the external heater, wherein the external heater is an electrical resistance heater, and the internal heater is or includes a susceptor. In such embodiments, power can be supplied to the inductor to inductively heat the susceptor, allowing the susceptor to function as the internal heater.

[0026] In the fifth configuration, the device comprises an external heater, the device comprises an inductor separate from the external heater, the article comprises an internal heater, the external heater is an electrical resistance heater, and the internal heater is or includes a susceptor. In such embodiments, power can be supplied to the inductor to inductively heat the susceptor, enabling the susceptor to function as an internal heater.

[0027] Any additional features of the aspects of this disclosure are described below. As a person skilled in the art will understand after reading this disclosure, these additional features may relate to one or more or all of the configurations described in the five paragraphs above.

[0028] The multiple stages may include any one of the preheating stage, cooling stage, first stage, and second stage, or any combination of them, or all of them. All of the multiple stages may occur during a single usage session.

[0029] The method may include, during the first stage, controlling the power supply to one or both of the internal and external heaters to raise the temperature of the internal heater during the first stage, or maintaining the temperature of the internal heater above the ambient temperature during the first stage. The method may also include, during the second stage following the first stage, controlling the power supply to the external heater to raise the temperature of the external heater during the second stage.

[0030] Advantageously, during the first stage, the temperature of the internal heater may rise. This could result in the internal heater heating the inner portion of the aerosol-forming substrate to form an aerosol during the first stage. As the first stage progresses, and heat propagates from the internal heater outward, the internal heater may heat more of the aerosol-forming substrate that is further away from the internal heater. As will be explained in more detail later, as the first stage progresses, the temperature of the internal heater may rise to assist this. However, if the internal heater heats up too high, there is a risk of overheating and scorching the aerosol-forming substrate that is closer to the internal heater. Thus, advantageously, after the first stage, during the second stage, the temperature of the internal heater may not rise any further, while the temperature of the external heater may rise. This could result in the external heater heating the outer portion of the aerosol-forming substrate to form an aerosol during the second stage. As the second stage progresses, and heat propagates from the external heater inward, the external heater may heat more of the aerosol-forming substrate that is further away from the external heater. As will be explained in more detail later, as the second stage progresses, the temperature of the external heater may rise to assist in this process. Therefore, the inner portion of the aerosol-forming substrate may be significantly consumed during the first stage, and the outer portion of the aerosol-forming substrate may be significantly consumed during the second stage. This has the advantage of resulting in the consumption of virtually all of the aerosol-forming substrate, thus reducing the amount of wasted aerosol-forming substrate and lowering the risk of overheating and combustion of the aerosol-forming substrate.

[0031] During the first stage, increasing the temperature of the internal heater, and during the second stage, increasing the temperature of the external heater, is more advantageous than the reverse. This is because it may be possible to form aerosols more quickly using the internal heater than the external heater. This is likely because the internal heater is more likely to be in closer thermal contact with the aerosol-forming substrate than the external heater. Therefore, this has the advantage of reducing the minimum time required for the system to initially generate aerosols.

[0032] The method may include controlling the power supply to one or both of the internal and external heaters during the preheating phase to raise the temperature of the internal heater to at least the minimum preheating temperature of the internal heater. The method may also include controlling the power supply to one or both of the internal and external heaters during the cooling phase following the preheating phase to lower the temperature of the internal heater to a temperature lower than the minimum preheating temperature of the internal heater. The method may also include controlling the power supply to one or both of the internal and external heaters during a first phase following the cooling phase to raise the temperature of one or both of the internal and external heaters.

[0033] The preheating phase has the advantage of reducing the time required for aerosol generation after the user first starts the system. The cooling phase, advantageously, can reduce the risk of the heater overheating, the aerosol-forming substrate burning, or excessive aerosol-forming substrate heating up and generating aerosols during the first few puffs of a usage session, resulting in little unused aerosol-forming substrate remaining for aerosol generation after the usage session. Advantageously, the first phase may allow for the consumption of more aerosol-forming substrate. For example, if the first phase involves one or both of the internal and external heaters gradually increasing the temperature between multiple puffs, as the first phase progresses, more of the aerosol-forming substrate may be heated to a temperature sufficient to generate aerosols. Therefore, advantageously, combining these three features makes it possible to shorten the time to the first puff without compromising the user experience towards the end of the usage session, as the substrate is neither excessively consumed nor heated enough to consume the remaining substrate. These three features also work synergistically to provide the advantage of enabling more consistent aerosol generation from the start to the end of a usage session compared to conventional aerosol generation systems. In particular, raising the temperature of the internal heater during the preheating phase can allow the substrate to heat up sufficiently quickly, enabling the generation of a large amount of aerosol during the initial stages of the usage session. Then, lowering the temperature of the internal heater during the cooling phase can enable the generation of sufficient aerosol during the middle stages of the usage session while preventing the generation of excessive aerosol. Subsequently, raising the heater temperature during the first stage can enable the generation of sufficient aerosol during the latter half of the usage session, when most of the aerosol-forming substrate has already heated up and formed aerosols.

[0034] If necessary, the method includes controlling the power supply to the internal heater during any stage according to the internal heater power supply profile for that particular stage. If necessary, the method includes controlling the power supply to the external heater during any stage according to the external heater power supply profile for that particular stage. Thus, the method may also include controlling the power supply to the internal heater according to one or more of the following: the internal heater power supply profile for the preheating stage during the preheating stage, the internal heater power supply profile for the cooling stage during the cooling stage, the internal heater power supply profile for the first stage during the first stage, and the internal heater power supply profile for the second stage during the second stage. Similarly, the method may also include controlling the power supply to the external heater according to one or more of the external heater power supply profile for the preheating stage during the preheating stage, the external heater power supply profile for the cooling stage during the cooling stage, the external heater power supply profile for the first stage during the first stage, and the external heater power supply profile for the second stage during the second stage.

[0035] Any power profile may differ from any other power profile. For example, the internal heater power profile for the first stage may differ from the internal heater power profile for the second stage. The external heater power profile for the first stage may differ from the external heater power profile for the second stage. By adjusting the heater power profile for each stage, it may be possible to adjust whether or not aerosols are formed between these stages, or the amount and composition of the aerosols that are formed.

[0036] If the apparatus includes an internal heater, the internal heater may extend from the base of the chamber. The internal heater may extend into the chamber, for example toward the open end of the chamber. The internal heater may be formed as a pin, blade, or rod for penetrating the aerosol-forming substrate of an article inserted into the chamber.

[0037] If the internal heater is an electrical resistance heater, it may comprise an electrically insulated substrate and a conductive track on the electrically insulated substrate. The device may be configured to pass current through the conductive track during use. This allows the conductive track to be electrically resistively heated.

[0038] The external heater may at least partially enclose or define the chamber for receiving the article. If the external heater is an electrical resistance heater, it may be substantially tubular in shape. The external heater may comprise an electrically insulated substrate, for example, a substantially tubular electrically insulated substrate, and a conductive track on the electrically insulated substrate. The device may be configured to pass an electric current through the conductive track during use. This allows the conductive track to be electrically resistance heated.

[0039] For example, suitable electrical insulating materials for electrically insulated substrates of electrical resistance internal or external heaters may include one or more of glass, ceramics, anodized metals, coated metals, and polyimides. Ceramics may include mica, alumina, or zirconia.

[0040] For example, suitable conductive materials for the electrical resistance track of an internal or external heater include one or more semiconductors, such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilide), carbon, graphite, metals, metal alloys, and composite materials made from ceramic and metal materials. Such composite materials may include doped ceramics or undoped ceramics. A suitable example of a doped ceramic is doped silicon carbide. Suitable metals include titanium, zirconium, tantalum, and platinum group metals. Suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum alloys. The electrical resistance track may include heated wires or filaments, such as Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wires or filaments.

[0041] If the external heater is an electrical resistance heater, the external heater may include, or be formed from, one or both of a substantially magnetically transparent material and a non-inductively heatable material. This may be particularly advantageous when the system also includes an inductor, as in the fourth and fifth arrangements described above.

[0042] If the external heater is an inductor, for example, an inductor coil, or includes one, the external heater may at least partially surround or define the chamber, or may be received within the chamber. The inductor coil may be a helical coil, or may include one. The inductor may be configured to contact, and therefore directly heat, an article received within the chamber. The inductor coil may be configured to surround or encircle an article received within the chamber. This has the advantage that it may allow for a concentrated magnetic field around the susceptor and heating around the entire circumference of the article by resistive heating of the inductor coil itself.

[0043] As an alternative to a helical inductor coil, the inductor may be or may include a flat spiral coil, also known as a pancake coil. The flat spiral coil may be wound spirally in a single plane, for example, around a central point. Similar to a helical inductor coil, the flat spiral coil may be configured to generate an alternating magnetic field within the chamber when an alternating current is supplied, and may allow external heating from the resistive heating of the inductor itself. The flat spiral coil may form the side walls or base of the chamber, or may be positioned adjacent to and in contact with the side walls or base as needed.

[0044] A susceptor, also known as a susceptor element, contains or consists of one or more susceptor materials.

[0045] Suitable susceptor materials include, but are not limited to, carbon, carbon-based materials, graphene, graphite, expanded graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Suitable susceptor materials may also include ferromagnetic materials, such as ferrite iron, ferromagnetic alloys, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. The susceptor material may contain more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent, or more than 90 percent of ferromagnetic or paramagnetic material. Suitable susceptor materials may include metals, metallic alloys, or carbon.

[0046] If the external heater is an inductor or includes an inductor, the method may include controlling the power supply to the external heater during the first stage according to the external heater power supply profile of the first stage in order to inductively heat the susceptor. If the external heater is an inductor or includes an inductor, the method may also include controlling the power supply to the external heater during the second stage according to the external heater power supply profile of the second stage in order to resistively heat the inductor, for example, resistively heating the inductor more during the second stage than during the first stage.

[0047] If necessary, the inductor is heated to a higher temperature during the second stage than during the first stage, for example, by resistance heating. If necessary, the peak temperature of the inductor during the second stage is higher than the peak temperature of the inductor during the first stage, for example, by at least 20, 50, or 100 degrees Celsius. If necessary, the average temperature of the inductor during the second stage is higher than the average temperature of the inductor during the first stage, for example, by at least 20, 50, or 100 degrees Celsius. Advantageously, if the heating of the external heater is better greater during the second stage compared to the first stage, it may allow the outer portion of the aerosol-forming substrate to be significantly consumed during the second stage. As a result, there is almost no waste of the outer portion of the aerosol-forming substrate.

[0048] If necessary, the inductor temperature at the end of the second stage is higher than the inductor temperature at the start of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Advantageously, further heating of the external heater as the second stage progresses may allow the external heater to heat more of the aerosol-forming substrate that is further away from the external heater. This has the advantage of potentially allowing the initial aerosol formation from the outermost part of the aerosol-forming substrate, followed by aerosol formation from progressively more inward-located portions of the aerosol-forming substrate. As a result, there is virtually no waste of the outer portion of the aerosol-forming substrate.

[0049] Controlling the power supply to the inductor, as needed, involves controlling one or both of the frequency and magnitude of the alternating current supplied to the inductor. The inductive coupling between the inductor and the susceptor may change in response to changes in the frequency of the alternating current supplied to the inductor. The frequency is a value f associated with the alternating current that generates an alternating magnetic field that maximizes energy transfer to the susceptor. susceptor The frequency may be adjusted to have such a frequency that, as a result, most of the heat is generated by heating the susceptor. The frequency is also a value f associated with the alternating current that generates an alternating magnetic field that provides little or no energy transfer to the susceptor. inductor It may be adjusted to have such that all or most of the heat is generated by the resistive heating of the inductor. The frequency is also a value f associated with the alternating current, which results in a combination of susceptor heating and resistive heating of the inductor. total These frequencies can be adjusted to have the following characteristics. Each of these frequencies varies depending on the materials, physical properties, and configuration of the inductor and susceptor, such as the inductance of the inductor coil and the permeability of the material used for the susceptor. By adjusting the frequencies, it is possible to adjust how much of the power from the power source is used for resistive heating of the inductor and how much of the power is used for inductive heating of the susceptor.

[0050] If necessary, controlling the power supply to the external heater according to a first-stage external power supply profile includes supplying an AC current of a first frequency to the inductor. If necessary, controlling the power supply to the external heater according to a second-stage external heater power supply profile includes supplying an AC current of a second frequency different from the first frequency to the inductor. Controlling the frequency of the current to the inductor has the advantage of providing an easy way to control the heating of the internal and external heaters.

[0051] If necessary, supplying an AC current of a first frequency to the inductor results in either or both greater inductive heating of the susceptor and less resistive heating of the inductor compared to supplying an AC current of a second frequency to the inductor. If necessary, supplying an AC current of a second frequency to the inductor results in either or both greater resistive heating of the inductor and less inductive heating of the susceptor compared to supplying an AC current of a first frequency to the inductor. This has the advantage of allowing either or both greater heating of the susceptor during the first stage compared to the second stage, and greater heating of the inductor during the second stage compared to the first stage.

[0052] If necessary, controlling the power supply to the external heater according to the second-stage external heater power supply profile includes supplying DC to the inductor alone or in combination with AC current. Advantageously, supplying DC to the inductor can increase the heating of the inductor without significantly additionally heating the susceptor. Alternatively, DC may not be supplied to the inductor in the first stage.

[0053] If necessary, power is not supplied to the external heater during the first stage. If necessary, the external heater is not heated above 100 degrees Celsius during the first stage. This has the advantage of saving power during the first stage, while heating the aerosol-forming substrate to form an aerosol using an internal heater, which may be part of the apparatus and electrically resistively heated.

[0054] The method may include starting or adjusting the power supply to one or both of the internal and external heaters as a function of one or more of the following: a) the number of times smoke is extracted during the usage session, b) the time elapsed since the start of the usage session, and c) detection of smoke extraction during the usage session.

[0055] The apparatus may include a thermally conductive element, also referred to herein as a thermally conductive bridging element. The thermally conductive bridging element may be positioned between the inductor and the chamber. The thermally conductive bridging element may be in contact with the inductor. The thermally conductive bridging element may be configured to contact the outer surface of the article to be received in the chamber. The thermally conductive bridging element may define the chamber at least partially. During use, heat may be transferred from the inductor through the thermally conductive bridging element to the article. The thermally conductive bridging element has the advantage of being able to heat the aerosol-forming substrate of the article more uniformly.

[0056] At least one of the controller, which may also be referred to herein as a control circuit, and the thermally conductive bridging element may be configured to prevent inductive coupling between the thermally conductive bridging element and the inductor during use.

[0057] The controller may be configured to provide alternating current at a frequency selected to prevent inductive coupling between the thermally conductive bridging element and the inductor during use.

[0058] The thermally conductive bridging element may be formed from a non-conductive material. The thermally conductive bridging element may be formed from a material that is substantially non-inductively heatable. The thermally conductive bridging element may include at least one of polymer materials and metals. The thermally conductive bridging element may include at least one of aluminum and paramagnetic steel. The paramagnetic steel may include austenitic steel.

[0059] The power supply may be configured to supply current to the thermally conductive bridging element during use, thereby resistively heating the thermally conductive bridging element. The thermally conductive bridging element may then be considered an external heater.

[0060] The external heater or thermally conductive bridging element may include a polymer material and at least one of graphite, graphite-derived material, and hexagonal boron nitride dispersed within the polymer material. The polymer material may also be called a polymer matrix. At least one of graphite, graphite-derived material, and hexagonal boron nitride may be present as filler particles within the polymer matrix. The polymer material may be at least one of polyether ether ketone (PEEK) and liquid crystal polymer (LCP), or may include both. The external heater or thermally conductive bridging element may contain 22 to 33 weight percent of the polymer material. The graphite-derived material may include at least one of expanded graphite and graphite nanoplatelets. The external heater or thermally conductive bridging element may contain 62 to 69 weight percent of graphite, graphite-derived material, and at least one of hexagonal boron nitride. The external heater or thermally conductive bridging element may contain at least one additive dispersed within the polymer material. At least one additive may contain carbon black. The external heater or thermally conductive bridging element may contain at least one additive in an amount of 5% to 9% by weight of the external heater. Advantageously, such external heaters or thermally conductive bridging elements may be easier to manufacture compared to others. More specifically, the thermoplastic properties of the polymer matrix can enable the composite polymer material to be malleable, thereby aiding in highly precise and controlled molding. Furthermore, by controlling and adjusting the concentration and distribution of conductive filler particles dispersed within the polymer matrix, along with other parameters, such as the length and cross-sectional area of ​​the external heater, it may be possible to achieve desirable heating properties, such as resistivity.

[0061] The inductor coil may be suspended within the chamber. Advantageously, this can reduce heat loss from the coil to the housing, potentially improving the efficiency of the device.

[0062] The inductor coil may be a helical coil. The helical coil may have a first end and a second end. The housing may only be in contact with the inductor coil at the first and second ends of the inductor coil.

[0063] The device may further include an airflow channel defined between the inner surface of the housing and the outer surface of the inductor coil. The airflow channel may provide fluid communication between the open end of the chamber and the base of the chamber.

[0064] An inductor coil may be formed from a coiled wire. The coiled wire may comprise a conductive core and a coating on the conductive core. The coating may be electrically insulating. The coating may contain at least one of polymer materials, ceramics, or glass. The inductor coil may contain a metal. The metal may contain copper.

[0065] The inductor coil may include a first tubular portion of a conductive material, a second tubular portion of a conductive material, and a helical coil of a conductive material extending between the first and second tubular portions. The helical coil may be formed integrally with the first and second tubular portions. Preferably, each of the first tubular portion, the second tubular portion, and each winding of the helical coil has a maximum width extending in a direction parallel to the longitudinal axis of the inductor coil, and the maximum widths of the first and second tubular portions are greater than the maximum widths of each winding of the helical coil.

[0066] The inductor coil may have a plurality of individual openings in at least one of the first tubular portion and the second tubular portion. The plurality of individual openings may be present in both the first tubular portion and the second tubular portion. The plurality of individual openings may be distributed symmetrically in the circumferential direction extending around the longitudinal axis of the inductor coil.

[0067] The inductor coil may further comprise a first tubular portion, a second tubular portion, and a layer of electrical insulating material extending around the outer surface of the helical coil.

[0068] The power supply may comprise a first DC power supply, optionally in the form of batteries. The control circuit may comprise a DC / AC converter connected to the first DC power supply. The system, e.g., the apparatus or control circuit, may comprise power supply electronics which may be configured to operate at high frequencies. For the purposes of this application, the term “high frequency” may be understood to represent frequencies in the range of 1 to 30, or 1 to 10, or 5 to 7 megahertz. The power supply electronics may comprise a DC / AC converter connected to the first DC power supply. The DC / AC converter may comprise a Class E power amplifier comprising a first transistor switch and an LC load circuit. Class E power amplifiers are generally known and are described in detail, for example, in the article “Class-E RF Power Amplifiers,” by Nathan O. Sokal, published, for example, in the bimonthly journal QEX, January / February 2001, pp. 9-20, of the American Radio Relay League (ARRL), Newington, CT, USA. The LC load circuit may comprise a shunt capacitor and a series connection of the capacitor and an inductor coil. The power supply electronic equipment preferably includes a second DC power supply connected to the LC load circuit at a position between the capacitor and the inductor coil in order to supply DC current to the inductor coil. The second DC power supply may be the same power source as the first DC power supply. For example, they may be the same battery. The power supply electronic equipment may include a choke inductor between the second DC power supply and the capacitor. The choke inductor preferably has a higher inductance value than the inductor coil. The power supply electronic equipment may also include a choke inductor between the first DC power supply and the capacitor. The power supply electronic equipment may include a second switch between the second DC power supply and the inductor coil. The second switch may be a second transistor switch. The power supply electronic equipment may include a second capacitor connected in parallel with the inductor coil. This allows fsusceptor and f inductor This may reduce the difference between the two.

[0069] If necessary, the method includes a preheating step. The preheating step may be part of the first step, or it may end before the start of the first step. If the preheating step is part of the first step, it may start at the start of the first step. If the preheating step is part of the first step, it may end before the first step is completed, for example, before half the total time of the first step has elapsed.

[0070] If necessary, the method includes controlling the power supply to the internal heater during the preheating stage according to the internal heater power supply profile of the preheating stage. If necessary, the method includes controlling the power supply to the external heater during the preheating stage according to the external heater power supply profile of the preheating stage. If necessary, the internal heater power supply profile of the preheating stage is different from one or both of the internal heater power supply profiles of the first stage and the second stage. If necessary, the external heater power supply profile of the preheating stage is different from one or both of the external heater power supply profiles of the first stage and the second stage. Advantageously, the preheating stage may allow the system to rapidly prepare for aerosol formation.

[0071] If necessary, virtually no aerosols are formed during the preheating stage. Advantageously, this may allow more aerosols to be formed in the first and second stages.

[0072] If necessary, during the preheating phase, the internal heater is heated to at least its minimum preheating temperature. If necessary, during the preheating phase, the external heater is heated to at least its minimum preheating temperature. The minimum preheating temperature of the internal heater may be higher than the minimum preheating temperature of the external heater.

[0073] If necessary, during the preheating phase, the internal heater is heated to a higher temperature than the external heater. This may be advantageous if, in the first stage, the internal heater primarily plays the role of heating the aerosol-forming substrate to form aerosols.

[0074] If necessary, the power supplied to the internal heater during the preheating phase is one or more of the power supplied to the internal heater during the first phase and the power supplied to the internal heater during the second phase. If necessary, the peak temperature reached by the internal heater during the preheating phase is one or more of the peak temperature reached by the internal heater during the first phase and the peak temperature reached by the internal heater during the second phase. Advantageously, this may allow for rapid aerosol formation during the first phase, thereby reducing the minimum time required for the system to initially generate aerosols.

[0075] If necessary, during the preheating phase, the internal heater is heated, but the external heater is not substantially heated. During the preheating phase, the external heater must not be heated above 100 degrees Celsius. If necessary, power is not supplied to the external heater during the preheating phase. Advantageously, this saves power, especially when the external heater does not need to reach the high temperature required for the second stage.

[0076] If necessary, during at least part of the preheating phase, the temperature of the internal heater, for example, the minimum preheating temperature of the internal heater, is at least one of the following: 100, 200, or 300 degrees Celsius, and 500 or 400 degrees Celsius or lower. If necessary, during at least part of the preheating phase, the temperature of the internal heater, for example, the minimum preheating temperature of the internal heater, is 200 to 500 degrees Celsius, or 200 to 400, or 300 to 400 degrees Celsius, preferably about 350 degrees Celsius. If necessary, during at least part of the preheating phase, the temperature of the external heater, for example, the minimum preheating temperature of the external heater, is at least one of the following: 100 or 200 degrees Celsius, and 500, 400, or 300 degrees Celsius or lower. If necessary, during at least part of the preheating phase, the temperature of the external heater, for example, the minimum preheating temperature of the external heater, is 100-500 degrees Celsius, or 100-400 degrees Celsius, or 100-300 degrees Celsius, or 200-500 degrees Celsius, or 200-400 degrees Celsius, preferably about 240 degrees Celsius. Advantageously, such temperatures may offer an optimal compromise between rapid initial heating and the risk of scorching the aerosol-forming substrate.

[0077] If necessary, the temperature of the external heater is at least 210 degrees Celsius during the preheating stage and at least part of one or two or all of the first and second stages.

[0078] If necessary, the preheating phase may last for at least 5, 10, 20, or 30 seconds. If necessary, the preheating phase may last for 60, 45, or 30 seconds or less. If necessary, the preheating phase may last for 5 to 60 seconds, or 5 to 45 seconds. Advantageously, this may allow the internal heater to be sufficiently preheated without taking an unnecessarily long time that would frustrate the user.

[0079] If necessary, the method includes a cooling step. If necessary, the cooling step takes place after the preheating step, for example, immediately after the preheating step. The first step may take place after the cooling step, for example, immediately after the cooling step.

[0080] If necessary, during the cooling phase, the temperature of the internal heater will decrease, for example, from at least the minimum preheating temperature of the internal heater. If necessary, during the cooling phase, the temperature of the internal heater will decrease by at least 10, 20, 50, or 100 degrees Celsius. If necessary, during the cooling phase, the temperature of the internal heater will decrease to a temperature below 300 or 250 degrees Celsius. If necessary, during the cooling phase, the temperature of the internal heater will decrease to at least 150 or 200 degrees Celsius.

[0081] If necessary, during the cooling phase, the temperature of the external heater will decrease, for example, from at least the minimum preheating temperature of the external heater. If necessary, during the cooling phase, the temperature of the external heater will decrease by at least 10, 20, 50, or 100 degrees Celsius. If necessary, during the cooling phase, the temperature of the external heater will decrease to a temperature below 300 or 250 degrees Celsius. If necessary, during the cooling phase, the temperature of the external heater will decrease to at least 100, 150, or 200 degrees Celsius.

[0082] The temperature drop of the internal heater during the cooling phase may be greater than the temperature drop of the external heater during the cooling phase. This may be because, at least one of the reasons is that the internal heater may be at a higher temperature than the external heater at the end of the preheating phase and / or the start of the cooling phase.

[0083] Advantageously, the cooling phase reduces the risk of the heater overheating, the aerosol-forming substrate burning, or excessive heating of the aerosol-forming substrate during the first few fumigations of a usage session, resulting in little unused aerosol-forming substrate remaining for generating aerosols for fumigation after the usage session.

[0084] If necessary, power is not supplied to the internal heater for at least a portion of the cooling phase, for example, during the initial part of the cooling phase. If necessary, power is not supplied to the external heater for at least a portion of the cooling phase, for example, during the initial part of the cooling phase. Advantageously, this allows for the fastest possible cooling rate and, as a result, ensures that the initial fumes do not consume excessive aerosols.

[0085] If necessary, the cooling phase may last for at least 60, 90, 120, 150, or 180 seconds. If necessary, the cooling phase may last for 360, 300, 270, or 240 seconds or less. If necessary, the cooling phase may last for 60–360 seconds, or 60–300 seconds, or 90–270 seconds. If necessary, the cooling phase may last for the duration of at least one smoke inhalation, and optionally for at least two, three, or five smoke inhalations. If necessary, the cooling phase may last for 10, or eight, or six or less smoke inhalations. If necessary, the cooling phase may last for 1–10, or 1–8, or 2–8, or 2–8, or 2–6 smoke inhalations. Advantageously, such durations allow for optimal cooling of one or both the internal and external heaters. This ensures that, during the initial smoke inhalation of a session of use, a sufficient but not excessive amount of aerosol-forming substrate is heated to form aerosols. This also ensures that there is enough unused aerosol-forming substrate in the subsequent smoke inhalation to heat and form an aerosol.

[0086] If necessary, one or both of the first and second stages are aerosol generation stages. If necessary, the first stage immediately follows the preheating stage. If necessary, the second stage immediately follows the first stage.

[0087] If necessary, the average or peak temperature of the internal heater during the first stage shall be higher than the average temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius. If necessary, the internal heater shall be heated during the first stage, while the external heater shall not be substantially heated. During the first stage, the external heater shall not be heated above 100 degrees Celsius. If necessary, power shall not be supplied to the external heater during the first stage.

[0088] If necessary, the temperature of the internal heater is high enough to form an aerosol from the aerosol-forming substrate for at least part of the first stage. If necessary, the temperature of the internal heater is at least 150, 200, 250, or 300 degrees Celsius for at least part of the first stage. If necessary, the temperature of the internal heater is 500, 450, or 400 degrees Celsius or less for at least part of the first stage. If necessary, the temperature of the internal heater is 150-500, 200-450, or 250-400 degrees Celsius for at least part of the first stage. If necessary, the temperature of the external heater is at least 50, 100, 150, 200, 250, or 300 degrees Celsius for at least part of the first stage. If necessary, the temperature of the external heater is 500, 400, 300, or 200 degrees Celsius or less for at least part of the first stage. If necessary, the temperature of the external heater is 50–500 degrees Celsius, or 50–400 degrees Celsius, or 50–30 degrees Celsius, or 50–200 degrees Celsius, for at least part of the first stage. Advantageously, this allows for the generation of aerosols of the desired quantity and composition.

[0089] If necessary, one or both of the first and second stages may last for at least 60, 90, 120, 150, or 180 seconds. If necessary, one or both of the first and second stages may last for 360, 300, 270, or 240 seconds or less. If necessary, one or both of the first and second stages may last for 60–360, or 60–300, or 90–270 seconds. If necessary, one or both of the first and second stages may last for the duration of at least one inhalation, and optionally at least two, three, or five inhalations. If necessary, one or both of the first and second stages may last for 10 or 8 or fewer inhalations. If necessary, one or both of the first and second stages may last for 1–10, or 1–8, or 2–8, or 3–8 inhalations. Advantageously, such durations may allow for sufficient consumption of the aerosol-forming substrate.

[0090] If necessary, the temperature of one or both of the internal and external heaters is kept constant or increases during the first stage. If necessary, the temperature of one or both of the internal and external heaters at the end of the first stage is higher than its temperature at the beginning of the first stage. If necessary, the average temperature of one or both of the internal and external heaters during the first part of the first stage, e.g., the first half of the first part, is higher than or less than its average temperature during the subsequent second part of the first stage, e.g., the second half of the subsequent stage. If necessary, the temperature of one or both of the internal and external heaters increases monotonically, e.g., continuously, for at least part of the first stage. Advantageously, by increasing the heater temperature as the first stage progresses, the heaters can be made capable of sufficiently heating more of the aerosol-forming substrate that is further away from the heater as the first stage progresses, thereby forming aerosols. This can reduce the amount of wasted or unused aerosol-forming substrate.

[0091] The average temperature of the external heater during the first part of the first stage is particularly preferable to be greater than or equal to the average temperature of the external heater during the subsequent second part of the first stage. This is because, in some embodiments, it may not be necessary to increase the temperature of the external heater as the first stage progresses, and therefore not increasing the temperature of the external heater at this stage may be more energy efficient. For example, if the temperature of the internal heater does not decrease as the first stage progresses, in this case, the internal heater may allow aerosols to be generated from the outer parts of the inner part of the substrate as the first stage progresses. Therefore, it may not be necessary to heat the external heater to heat the outer part of the substrate to generate aerosols at this stage. This can be reserved for a second stage if one exists. This improves the energy efficiency of the method and allows for the provision of a constant amount of aerosol throughout the entire usage session.

[0092] The exemplary embodiments described in the two paragraphs above may be particularly preferred with respect to one or more or all of the following: The average temperature of the internal heater during the first part of the first stage is 150-300 degrees Celsius. The average temperature of the internal heater between the second part following the first stage is higher than the average temperature of the internal heater between the first part of the first stage, preferably 200-400 degrees Celsius, more preferably 250-350 degrees Celsius. The average temperature of the external heater during the second part of the first stage is less than or equal to the average temperature of the external heater during the first part of the first stage, and is preferably 150 to 250 degrees Celsius. The average temperature of the external heater during the first part of the first stage is lower than the average temperature of the internal heater during the first part of the first stage, and is preferably between 150 and 250 degrees Celsius. The average temperature of the external heater during the second part of the first stage is lower than the average temperature of the internal heater during the second part of the first stage, and is preferably between 150 and 250 degrees Celsius. An example of this will be shown later in Figure 22.

[0093] If necessary, during at least part of the first stage, the temperature of the external heater is kept constant at one or more temperatures, for example, at least 150, 200, 250, or 300 degrees Celsius and 350, or 300 degrees Celsius or less. If necessary, during at least part of the first stage, the temperature of the external heater is kept constant at a temperature, for example, between 100 and 350 degrees Celsius, or between 150 and 300 degrees Celsius, or between 200 and 300 degrees Celsius. If necessary, during at least part of the first stage, the temperature of the internal heater may be increased, for example, by at least 10, 20, 50, or 100 degrees Celsius, or by at least 200, 250, or 300 degrees Celsius, or both. Advantageously, keeping the external heater temperature constant and increasing the internal heater temperature can allow for optimal consumption of the substrate during subsequent fume extraction. This can be particularly advantageous when there is no second stage after the first stage.

[0094] If necessary, the internal heater temperature is maintained at the first internal heater temperature of the first stage for at least a portion of the first stage, for example, during the first part. If necessary, the internal heater temperature is maintained at the second internal heater temperature of the first stage, which is different from the first internal heater temperature of the first stage, during the second part following the first part of the first stage. If necessary, the internal heater temperature is maintained at the third internal heater temperature of the first stage, which is different from one or both of the first internal heater temperature of the first stage and the second internal heater temperature of the first stage, during the third part following the second part of the first stage.

[0095] If necessary, the temperature of the second internal heater in the first stage is higher than the temperature of the first internal heater in the first stage, for example, by at least 5, 10, 20, 30, or 50 degrees Celsius. If necessary, the temperature of the third internal heater in the first stage is higher than one or both of the temperatures of the first internal heater in the first stage and the second internal heater in the first stage, for example, by at least 5, 10, 20, 30, or 50 degrees Celsius. Advantageously, by sequentially maintaining the internal heater temperature at higher temperatures as the first stage progresses, it is possible to allow the internal heater to sufficiently heat more of the aerosol-forming substrate that is further away from the internal heater to form aerosols as the first stage progresses.

[0096] If necessary, the temperature of the external heater is maintained at the first external heater temperature of the first stage for at least a portion of the first stage. If necessary, the temperature of the external heater is maintained at the first external heater temperature of the first stage for the first part of the first stage. If necessary, the temperature of the external heater is maintained at a second external heater temperature of the first stage, different from the first external heater temperature of the first stage, for the second part following the first part of the first stage. If necessary, the temperature of the external heater is maintained at a third external heater temperature of the first stage, different from one or both of the first external heater temperature of the first stage and the second external heater temperature of the first stage, for the third part following the second part of the first stage.

[0097] If necessary, the temperature of the second external heater in the first stage is higher than the temperature of the first external heater in the first stage, for example, by at least 5, 10, 20, 30, or 50 degrees Celsius. If necessary, the temperature of the third external heater in the first stage is higher than one or both of the temperatures of the first external heater in the first stage and the second external heater in the first stage, for example, by at least 5, 10, 20, 30, or 50 degrees Celsius. Advantageously, by sequentially maintaining the temperature of the external heater at higher temperatures as the first stage progresses, the external heater can be prepared for the second stage, where the second heater may be more important than the internal heater for heating the substrate and forming aerosols. Advantageously, by sequentially maintaining the temperature of the external heater at higher temperatures as the first stage progresses, the external heater can be made to sufficiently heat more of the aerosol-forming substrate further away from the external heater to form aerosols as the first stage progresses.

[0098] If necessary, the external heater is heated during the second stage, but the internal heater is not heated substantially during the second stage. If necessary, power is not supplied to the internal heater during the second stage. Advantageously, since the internal heater may already be hot when the second stage begins, and the external heater may, primarily or solely, play a role in heating the outer portion of the aerosol-forming substrate to form aerosols during the second stage, power can be saved without impairing aerosol generation by hardly or not heating the internal heater during the second stage.

[0099] If necessary, the average or peak temperature of the internal heater during the second phase is higher than the average temperature of the external heater during the second phase, for example, by at least 20, 50, or 100 degrees Celsius. The external heater is primarily responsible for heating the outer portion of the substrate to form aerosols, but it may not be necessary to heat the external heater to the same high temperature as the internal heater, as the aerosol-forming substrate may already be warm when the second phase begins.

[0100] If necessary, the temperature of one or both of the internal and external heaters is at least 150, 200, 250, or 300 degrees Celsius for at least part of the second stage. If necessary, the temperature of one or both of the internal and external heaters is 500, 450, or 400 degrees Celsius or less for at least part of the second stage. If necessary, the temperature of one or both of the internal and external heaters is 150–500, 200–450, or 250–400 degrees Celsius for at least part of the second stage. Advantageously, these temperatures can enable the generation of aerosols of a desired quantity and composition. This makes it possible, in particular, to heat the outer portion of the aerosol-forming substrate to a sufficiently high temperature by using an external heater, or by using both the internal and external heaters in combination, and generate aerosols of a desired quantity and composition.

[0101] The temperature of one or both of the internal and external heaters may be at least 200, 250, 300, or 350 degrees Celsius at the end of the second stage. If necessary, the temperature of the external heater at the end of the second stage may be either or both of the following: lower than 20, 50, or 100 degrees Celsius higher than the internal heater temperature at the end of the second stage, and higher than 20, 50, or 100 degrees Celsius higher than the internal heater temperature at the end of the second stage. Advantageously, heating of the aerosol-forming substrate can be maximized without excessive risk of overheating or burning, provided that the internal and external heaters reach similar temperatures at the end of the second stage, not significantly lower than temperatures at which there is a risk of overheating or burning.

[0102] If necessary, the temperature of the external heater at the end of the second stage is higher than the temperature of the external heater at the start of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Advantageously, as the second stage progresses, by increasing the temperature of the external heater, more of the aerosol-forming substrate further away from the external heater can be heated to sufficiently high temperatures to form aerosols.

[0103] If necessary, the temperature of the internal heater is kept constant or decreases, for example, monotonically or continuously, for at least part of the second stage.

[0104] If necessary, during the first part of the second stage, for example, the first half of the second stage, the average temperature of the internal heater is greater than or equal to the average temperature of the internal heater during the second part of the second stage, for example, the second half of the second stage. During the second stage, the external heater is mainly or solely responsible for heating the aerosol-forming substrate to form aerosols, so there is no need to raise the temperature of the internal heater during the second stage.

[0105] If necessary, the temperature of the external heater is kept constant or increases during the second stage. If necessary, the temperature of the external heater at the end of the second stage is higher than the temperature of the external heater at the beginning of the second stage. If necessary, during the first part of the second stage, e.g., the first half of the second stage, the average temperature of the external heater is lower than or higher than the average temperature of the external heater during the subsequent second part of the second stage, e.g., the subsequent second half of the second stage. If necessary, the temperature of the external heater increases substantially monotonically, e.g., continuously, for at least part of the second stage. Advantageously, by increasing the temperature of the external heater as the second stage progresses, the external heater can be allowed to gradually and sufficiently heat more of the aerosol-forming substrate that is further away from the external heater to form aerosols as the second stage progresses.

[0106] If necessary, the temperature of the external heater is maintained at the first external heater temperature of the second stage for at least part of the second stage. If necessary, the temperature of the external heater is maintained at the first external heater temperature of the second stage for the first part of the second stage. If necessary, the temperature of the external heater is maintained at a second external heater temperature of the second stage, different from the first external heater temperature of the second stage, for the second part following the first part of the second stage. If necessary, the temperature of the external heater is maintained at a third external heater temperature of the second stage, different from one or both of the first external heater temperature of the second stage and the second external heater temperature of the second stage, for the third part following the second part of the second stage. If necessary, the second external heater temperature of the second stage is higher than the first external heater temperature of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. If necessary, the temperature of the third external heater in the second stage is higher than one or both of the temperatures of the first external heater in the second stage and the second external heater in the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Advantageously, as the second stage progresses, by sequentially maintaining the temperature of the external heater at higher temperatures, it is possible to allow the external heater to sufficiently heat more of the aerosol-forming substrate that is further away from the external heater to form aerosols. This can reduce the amount of wasted or unused aerosol-forming substrate on the outer portion of the aerosol-forming substrate.

[0107] If necessary, the internal heater power profile for the first stage differs from the internal heater power profile for the second stage. If necessary, the external heater power profile for the first stage differs from the external heater power profile for the second stage. Advantageously, adjusting the power profiles can make it possible to adjust aerosol formation. For example, such adjustments can make it possible to fully consume the internal portion of the substrate during the first stage, followed by fully consuming the external portion of the substrate during the second stage.

[0108] If necessary, the average or peak temperature of the external heater during the second stage is higher than the average temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius. If necessary, the average temperature difference between the internal and external heaters during the first stage is higher than the average temperature difference between the internal and external heaters during the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Advantageously, such heating of the external heater during the second stage can allow the external heater to heat the outer portion of the substrate to form an aerosol during the second stage. This prevents waste of the outer portion of the substrate.

[0109] If necessary, the average temperature difference between the internal and external heaters at the start of the second stage is greater than 20, 50, or 100 degrees Celsius. If necessary, the average temperature difference between the internal and external heaters at the end of the second stage is less than 20, 50, or 100 degrees Celsius. Advantageously, by heating the external heater during the second stage to a temperature similar to that of the internal heater, the outer portion of the substrate can be heated sufficiently to form an aerosol.

[0110] As those skilled in the art will understand after reading this disclosure, the internal heater may still contribute to heating the substrate during the second stage. However, this contribution may have a smaller effect on aerosol formation compared to the external heater during the second stage and the internal heater during the first stage.

[0111] If necessary, the start of the second stage may be triggered by a predetermined number of fumigations of the aerosol-forming substrate during the current usage session, e.g., two, three, four, or five fumigations of the aerosol-forming substrate during the current usage session, or by a predetermined time elapsed since the first fumigation of the aerosol-forming substrate, or by the activation of the internal or external heater, e.g., a predetermined time elapsed since the initial activation, or by a predetermined time elapsed since the internal or external heater reached a predetermined temperature, or by the start of a preheating phase, the end of a preheating phase, or a predetermined time elapsed since the start of the first stage, or by the activation of a user-activatable trigger, or a combination of one or more of these options. A simple example of one combination of these options is that the start of the second stage may be triggered as soon as a user-activatable trigger is activated and a predetermined time has elapsed since the start of the first stage. Advantageously, starting the second stage after such a trigger point allows the first stage to have sufficient time to form aerosols from most of the inner portion of the substrate, and at the same time, allows sufficient time for a typical aerosol-generating experience to form aerosols from most of the outer portion of the substrate during the second stage.

[0112] The method may include continuously supplying power to at least one of the internal and external heaters from at least one power source. The method may also include continuously heating at least one of the internal and external heaters. In other words, the method may include not supplying power to or heating both the internal and external heaters at the same time. If both the internal and external heaters need to be heated to or above ambient temperature at the same time or at approximately the same time, the method may include alternating between supplying power to or heating the internal heater and supplying power to or heating the external heater, for example, multiple times per second. This may advantageously reduce the maximum amount of power that the battery can supply. Alternatively, or further, this may simplify and be advantageous in controlling the power supply to the internal and external heaters.

[0113] As described above, the external heater may be an inductor, and the internal heater may be a susceptor. In this case, power can be supplied to the external heater to inductively heat the internal heater. This power may cause the temperature of the external heater to rise very slightly (e.g., less than 15 degrees Celsius). However, in this situation, this is not considered heating the internal heater.

[0114] If the method includes a preheating step in which both the internal heater and the external heater are heated, the method may include, at the start of the preheating step, heating the internal heater to a temperature of 100 or 150 degrees Celsius before the external heater is heated to a temperature of at least 50 or 90 degrees Celsius.

[0115] The method may include heating the internal heater to a temperature above 100 or 150 degrees Celsius, then alternating between heating the internal heater and the external heater, or alternating between supplying power to the internal heater and the external heater, for example, multiple times per second, so that the temperatures of the internal heater and the external heater reach or are maintained at or near their respective target temperatures, for example, between one or more or all of the remaining preheating stage, the cooling stage, the first stage, and the second stage.

[0116] As described in the two paragraphs above, at the start of the preheating phase, the method may prioritize the internal heater over the external heater. This may be advantageous because, for rapid aerosol generation after startup, it may be more important for the internal heater to reach a high temperature quickly than for the external heater to reach a high temperature quickly.

[0117] Herein, a first preferred method according to the present disclosure will be described. As those skilled in the art will understand, the interchangeable features described above may be applicable to this first preferred method. And features described in connection with this first preferred method may be applicable to the aforementioned method. The first preferred method is a method for controlling an aerosol generating system, the aerosol generating system comprising an internal heater configured to heat an aerosol-forming substrate from inside the aerosol-forming substrate and an external heater configured to heat an aerosol-forming substrate from outside the aerosol-forming substrate.

[0118] The first preferred method is, During the first stage, for example, throughout the entire first stage, the internal heater is heated or maintained at a temperature higher than a predetermined first temperature. During the first stage, for example, throughout the entire first stage, the external heater is heated or maintained at a temperature below a first predetermined temperature, A method comprising heating an external heater to a temperature higher than a first predetermined temperature during a second stage following a first stage.

[0119] Advantageously, as explained in more detail earlier, the internal heater can enable rapid aerosol generation towards the start of a session and can also heat the inner portion of the substrate to release aerosol during the first few fume extractions. An external heater may then be used to heat the outer portion of the substrate to release aerosol during subsequent fume extractions. This has the advantage of reducing the amount of substrate wasted.

[0120] As mentioned above, heating of the internal heater can be achieved by controlling the power supplied to one or both of the internal and external heaters. Heating of the external heater can be achieved by controlling the power supplied to the external heater.

[0121] During the first stage, heating or maintaining the internal heater to a temperature above a first predetermined temperature may be performed simultaneously with heating or maintaining the external heater to a temperature below the first predetermined temperature.

[0122] The first preferred method may include a preheating step. The preheating step may be performed before the first step. The features described herein in relation to the preheating step may be applied to the preheating step of the first preferred method.

[0123] The first preferred method may include a cooling step. The cooling step may occur after the preheating step, for example immediately after. The cooling step may occur before the first step, for example immediately before. The features described herein relating to the cooling step may be applied to the cooling step of the first preferred method. During the cooling step, one or both of the internal and external heaters may experience a temperature drop of at least 30 or 40 degrees Celsius in less than 10 or 15 seconds.

[0124] The first predetermined temperature may be 100 degrees Celsius or 150 degrees Celsius. As those skilled in the art will understand, the features described herein in relation to the first and second steps of this specification can be applied to the first and second steps of the first preferred method. Nevertheless, some particularly preferred features for the first and second steps are described below.

[0125] A first preferred method may include heating or maintaining the internal heater to a temperature above 100 or 150 degrees Celsius during the first stage, for example, for the entire first stage. A first preferred method may include heating or maintaining the internal heater to a temperature below 400 or 300 degrees Celsius during the first stage, for example, for the entire first stage. The temperature of the internal heater during the first stage shall not exceed 300 or 400 degrees Celsius. A first preferred method may include heating or maintaining the internal heater to a temperature between 100 and 400 degrees Celsius or between 150 and 300 degrees Celsius during the first stage, for example, for the entire first stage.

[0126] A first preferred method may include heating or maintaining the external heater at a temperature below 150 or 100 degrees Celsius during the first stage, for example, for the entire duration of the first stage. The temperature of the external heater during the first stage must not exceed 100 or 150 degrees Celsius. A first preferred method may include heating or maintaining the external heater at a temperature above 30 or 50 degrees Celsius during the first stage, for example, for the entire duration of the first stage. A first preferred method may include heating or maintaining the external heater at a temperature between 30 and 150 degrees Celsius or between 50 and 100 degrees Celsius during the first stage, for example, for the entire duration of the first stage.

[0127] The second step of the first preferred method or the method according to the first embodiment may occur after the first step, for example, immediately afterward. The start of the second step may be triggered by detecting that a predetermined number of fume extractions have been performed by the system during the current use session, for example, by detecting that three, four, five, or six fume extractions have been performed by the system during the current use session. This may be the point at which it becomes difficult to generate sufficient aerosol from inside the substrate using the internal heater without raising the temperature of the internal heater to the point where there is a risk of burning the substrate. Therefore, starting the second step at this stage may be particularly beneficial.

[0128] A first preferred method may include maintaining the temperature of the internal heater above a first predetermined temperature during the second stage, for example, for the entire duration of the second stage. A first preferred method may include maintaining the temperature of the internal heater above 100 or 150 degrees Celsius during the second stage, for example, for the entire duration of the second stage. A first preferred method may include maintaining the temperature of the internal heater below 400 or 300 degrees Celsius during the second stage, for example, for the entire duration of the second stage. The temperature of the internal heater during the second stage must not exceed 300 or 400 degrees Celsius. A first preferred method may include maintaining the temperature of the internal heater between 100 and 400 degrees Celsius or between 150 and 300 degrees Celsius during the second stage, for example, for the entire duration of the second stage.

[0129] A first preferred method may include heating the external heater to a first predetermined temperature or a temperature higher than 100 degrees Celsius or 150 degrees Celsius during the second stage. A first preferred method may include heating the external heater to a first predetermined temperature or a temperature higher than 100 or 150 degrees Celsius during the second stage, and then maintaining the external heater at a temperature higher than the first predetermined temperature or 100 or 150 degrees Celsius for the remainder of the second stage. A first preferred method may include heating the external heater to a temperature of 300 or 400 degrees Celsius or lower during the second stage. The temperature of the external heater during the second stage must not exceed 300 or 400 degrees Celsius. A first preferred method may include heating the external heater to 100-400 degrees Celsius or 150-300 degrees Celsius during the second stage. The first preferred method may include heating the external heater to a temperature of 100–400 degrees Celsius or 150–300 degrees Celsius during the second stage, and then maintaining the external heater at a temperature of 100–400 degrees Celsius or 150–300 degrees Celsius for the remainder of the second stage. The aforementioned characteristics relating to the duration of the first and second stages also apply to the first preferred method.

[0130] The first preferred method according to the first embodiment, or the second step of the method, may include two, three, four, or five consecutive parts. Each part may have the same duration, or may continue for the same number of smoke extractions detected by the system. The average temperature of the external heater between each part other than the first part may be higher than that of the preceding part, for example, at least 10, 20, or 30 degrees Celsius higher.

[0131] For example, the second stage may include three consecutive parts. The three consecutive parts may have the same duration or may continue for the same number of smoke extractions detected by the system. The average temperature of the external heater during the first part may be 30 to 150 degrees Celsius, the average temperature of the external heater during the second part occurring immediately after the first part may be 80 to 200 degrees Celsius, and the average temperature of the external heater during the third part occurring immediately after the second part may be 150 to 400 degrees Celsius. The inventors have found that during the first part, these temperature ranges can be surprisingly good because they can significantly reduce the cooling effect of the airflow on the internal heater by the external heater and help the internal heater generate aerosols from the inner part of the substrate. Next, during the second part, after the internal heater has consumed a considerable amount from the inner part of the substrate, the external heater may begin to substantially complement the internal heater by generating aerosols from the outermost part of the outer part of the substrate. Next, during the third part, the external heater becomes hot enough to heat a large portion of the outer part of the substrate, causing aerosol generation. Therefore, combining these three components offers the advantage of consistently generating high-quality aerosols throughout the entire usage session while minimizing the risk of the heater overheating and burning the substrate, and minimizing substrate waste by significantly heating both the inner and outer parts of the substrate.

[0132] A first preferred method or method according to the first embodiment may include, during the second stage, for example, for most or all of the second stage, raising the temperature of the external heater or target temperature monotonically or continuously, or monotonically or continuously, until it reaches the maximum allowable external heater temperature or target temperature.

[0133] A first preferred method or method according to the first embodiment may include, during the second stage, increasing the temperature of the external heater or target temperature in response to the detection of at least one smoke inhalation, for example, in response to the detection of at least one specific smoke inhalation, such as the fourth smoke inhalation detected during the second stage or the current usage session. The method may also include, during the second stage, increasing the temperature of the external heater or target temperature in response to the detection of a first predetermined number of smoke inhalations, for example, a first predetermined number of smoke inhalations during the current usage session or during the second stage. The method may then include, again increasing the temperature of the external heater or target temperature in response to the detection of a second predetermined number of smoke inhalations, for example, a second predetermined number of smoke inhalations during the current usage session or during the second stage. The method may also include, during the second stage, for example, during part or all of the second stage, increasing the temperature of the external heater or target temperature in response to each smoke inhalation detected during the second stage, or in response to each smoke inhalation detected during the second stage, until the maximum allowable external heater temperature or target temperature is reached. As mentioned above, the second stage may last for at least 60, 90, 120, 150, or 180 seconds, and for one or both of the durations of at least two, three, or five smoking cycles in the system.

[0134] A first preferred method or method according to the first embodiment may include, during the first part of the second stage, raising the temperature of the external heater or target temperature to, for example, 60 to 160 degrees Celsius, preferably 80 to 130 degrees Celsius, more preferably 100 to 125 degrees Celsius, in response to detecting a predetermined number of smoke extractions of the system during the second stage or the current usage session, for example, three, four, five, or six smoke extractions.

[0135] The first part of the second stage may begin at the start of the second stage. The first part of the second stage may continue for at least two predetermined number of smoke inhalations of the system during the current usage session, for example, at least two, three, or four smoke inhalations. During this first part of the second stage, the temperature of the external heater may not necessarily be high enough to generate a sufficient amount of aerosol from the outer part of the substrate. However, heating of the external heater can mean that the inner part of the substrate, which is heated mainly by the internal heater to form aerosols, is not cooled so much by the cold air passing through the substrate when the user smokes with the system. Thus, during the first part of the second stage, heating of the external heater has the advantage of helping to keep the inner part of the substrate at a suitable high temperature during smoke inhalation.

[0136] A first preferred method or method according to the first embodiment may include raising the temperature of an external heater or target temperature to, for example, 130 to 400 degrees Celsius, preferably 160 to 300 degrees Celsius, more preferably 180 to 250 degrees Celsius, in response to detecting a third predetermined number of smoke extractions of the system during the second part of the second stage, the second stage, or the current usage session, for example, six, seven, eight, nine, or ten smoke extractions.

[0137] The second part of the second stage may begin after, for example immediately after, the first part of the second stage. The second part of the second stage may continue for at least a fourth predetermined number of smoke inhalations of the system during the current usage session, for example, at least two, three, or four smoke inhalations. During this second part of the second stage, the temperature of the external heater may rise sufficiently high to generate aerosols from the outer part of the substrate.

[0138] The inventors found that the specific temperature range described in the above paragraph, when initiated in response to the number of smoke inhalations described in the above paragraph, has the advantage of enabling the delivery of a consistent, high-quality aerosol throughout the course of a typical use session.

[0139] The temperature of the external heater may be lower than the temperature of the internal heater, for example, during at least a portion of the first part or the initial part of the second stage, for example, during the initiation part. The temperature of the external heater may be higher than the temperature of the internal heater, for example, during at least a portion of the second part or the final part of the second stage, for example, during the final part.

[0140] Between the first and second stages, or both, the method may include increasing the power supply to one or both of the internal and external heaters in response to one or each of the smoke extractions. This can compensate for the smoke extraction or the cooling effect resulting from each smoke extraction.

[0141] As explained earlier, it may be preferable to heat one or more of the internal and external heaters during the preheating stage to minimize the time required to initially generate aerosols. This applies equally to the first preferred method which includes a preheating stage. Thus, the first preferred method may include heating the internal heater to at least the minimum internal heater preheating temperature and heating the external heater to at least the minimum external heater preheating temperature, or both, during the preheating stage. The minimum internal heater preheating temperature and the minimum external heater preheating temperature mentioned above apply equally here.

[0142] A system, e.g., a device, may be configured to determine or estimate the temperature of one or more of the internal heater, external heater, heating zone within the chamber, and aerosol-forming substrate. In this regard, determining the temperature of a component may mean determining the temperature at one or more locations of the component. The system, e.g., a device, may be equipped with temperature sensing means for this purpose. The temperature sensing means may be one or more dedicated temperature sensors, or may include them. Alternatively, or additionally, a controller may be configured to determine the temperature of a heater, e.g., a resistance heater, by measuring or calculating its electrical resistance. In this case, the controller may be considered to include temperature sensing means. This electrical resistance may be calculated by dividing the potential difference V across the heater by the current I flowing through the heater. The temperature of the heater may then be determined using the resistance-temperature dataset. Advantageously, the ability to precisely control the temperature of the aerosol-forming substrate has the benefit of enabling more precise control of the amount and composition of aerosols formed during use.

[0143] A system, for example, a device, may have an air intake. The mouthpiece of a system, for example, an article or device, may have an air outlet. A system, for example, an article, may have an airflow path. The airflow path may connect the air intake to the airflow outlet. During use, for example, in response to inhalation at any mouthpiece of the article or system, air may flow through the air intake, then through the article, and then through the air outlet. After flowing through the air outlet, the air may flow into the user's mouth.

[0144] The article may include a cartridge or may be in the form of a cartridge.

[0145] The article may look substantially similar to a conventional cigarette. The article may be substantially cylindrical, for example, a straight cylinder. The article may have a length of 30 mm to 120 mm, for example 40 mm to 80 mm, for example about 45 mm. The article may have an outer diameter of 3.5 mm to 10 mm, for example 4 mm to 8.5 mm, for example 4.5 mm to 7.5 mm.

[0146] The substrate may be substantially cylindrical, for example, a right cylinder. References in this specification are made to the inner and outer portions of the aerosol-forming substrate. The inner portion may be, or contain, the aerosol-forming material in the axial central portion of the aerosol-forming substrate, for example, the axial central cylindrical portion or the axial central right cylindrical portion. The outer portion may be, or contain, the aerosol-forming material in the axial outer portion of the aerosol-forming substrate. The outer portion may be cylindrical, for example, a right cylinder. The outer portion may have an annular cross-section, for example, a circular annular cross-section. There may be no aerosol-forming substrate between the inner and outer portions. The inner and outer portions may be in contact. The entire aerosol-forming material of the aerosol-forming substrate may reside within the inner and outer portions.

[0147] If necessary, the article comprises a front plug. If necessary, the article comprises an aerosol-forming substrate. If necessary, the article comprises a first hollow tube, e.g., a first hollow acetate tube. If necessary, the article comprises a second hollow tube, e.g., a second hollow acetate tube. Optionally, the second hollow tube comprises one or more vents. If necessary, the article comprises a mouth plug filter. If necessary, the article comprises a wrapper, e.g., a paper wrapper. If necessary, one or more or all of the front plug, aerosol-forming substrate, first hollow tube, second hollow tube (if present), and mouth plug filter are enclosed by the wrapper.

[0148] Optionally, a front plug is located at the upstream end of the article. Optionally, an aerosol-forming substrate is located downstream of the front plug. Optionally, a first hollow tube is located downstream of the aerosol-forming substrate. Optionally, a second hollow tube is located downstream of the first hollow tube. Optionally, a mouth plug filter is located downstream of one or both of the first and second hollow tubes. Optionally, the mouth plug filter is located at the downstream end of the article. Optionally, the downstream end of the article, which may also be referred to as the mouth end of the article, may be configured to be inserted into the user's mouth. The user may, for example, directly inhale the mouth end of the article.

[0149] One or more of the front plug, aerosol-forming substrate, first hollow tube, second hollow tube, and mouth plug filter may be substantially cylindrical, for example, a straight cylindrical shape. One or more of the front plug, aerosol-forming substrate, first hollow tube, second hollow tube, and mouth plug filter may have a diameter of 3.5 mm to 10 mm. If necessary, the front plug may have a length of 2 to 10 mm. If necessary, the aerosol-forming substrate in the article may have a length of 5 to 20 mm. If necessary, the first hollow tube may have a length of 2 to 20 mm. If necessary, the second hollow tube may have a length of 2 to 20 mm. If necessary, the mouth plug filter may have a length of 5 to 20 mm.

[0150] The housing of the device may be elongated. The housing may contain any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene.

[0151] The power source may be a battery, or may be equipped with one. The battery may be rechargeable. The battery may be a lithium-based battery, such as a lithium cobalt, lithium iron phosphate, lithium titanate, or lithium polymer battery, or a nickel-metal hydride or nickel-cadmium battery. The power source may be another form of charge storage device, such as a capacitor. The power source may have sufficient capacity to enable continuous generation of aerosol for at least 6 minutes, corresponding to the typical time it takes to smoke a conventional cigarette.

[0152] As used herein, the terms “aerosol-generating article” or simply “article” may refer to an article that can generate or release aerosols, for example, when heated.

[0153] As used herein, the term “aerosol-forming substrate” may refer to a substrate having the ability to release aerosols or volatile compounds that can form aerosols. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate may comprise one or more aerosol-forming bodies or aerosol-forming materials. The aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. Conveniently, the aerosol-forming substrate may be part of an aerosol-generating article or a smoking article.

[0154] If necessary, the aerosol-forming substrate is a solid aerosol-forming substrate. However, the aerosol-forming substrate may contain both solid and liquid components. Alternatively, the aerosol-forming substrate may be a liquid aerosol-forming substrate.

[0155] The aerosol-forming substrate may contain nicotine, if necessary. The aerosol-forming substrate may contain tobacco, if necessary. Alternatively, or additionally, the aerosol-forming substrate may contain a non-tobacco-containing aerosol-forming material.

[0156] As used herein, the term “aerosol-forming compound” may refer to any suitable known compound or mixture of compounds that promotes aerosol formation during use and is substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating article. Suitable aerosol-forming compounds are known in the art and include, but are not limited to, polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanediate and dimethyl tetradecanediate). Preferred aerosol-forming compounds are polyhydric alcohols or mixtures thereof (such as propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably glycerin). An aerosol-forming substrate may comprise one or more aerosol-forming compounds.

[0157] As used herein, the term “usage session” may refer to a period of time during which a user applies a series of inhalations to extract an aerosol from an aerosol-forming substrate. A usage session may include at least five inhalations. Inhalations may be applied to a system, for example, an article or mouthpiece of the system’s equipment. A usage session may refer to a session in which an aerosol is extracted from the aerosol-forming substrate of an aerosol-generating article. When the aerosol-forming substrate is consumed, the aerosol-generating article may be replaced and another usage session may begin.

[0158] As used herein, the term “aerosol generator” may refer to a device used in conjunction with an aerosol generating article to enable the generation or release of an aerosol.

[0159] As used herein, the term “susceptor” may refer to an element containing a material capable of converting magnetic field energy into heat. When a susceptor is located in an alternating magnetic field, it heats up. The heating of the susceptor may result from at least one of hysteresis losses and eddy currents induced within the susceptor, depending on the electrical properties and magnetism of the susceptor material.

[0160] As used herein, the term “inductively coupled” may refer to heating of a susceptor when penetrated by an alternating magnetic field. Heating may be caused by the generation of eddy currents within the susceptor. Heating may also be caused by magnetic hysteresis losses.

[0161] As used herein, the term "inhaling smoke" may refer to the act of a user inhaling an aerosol into their body through their mouth or nose.

[0162] As used herein, when referring to an aerosol-generating article, the terms “upstream” and “downstream” may be 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. An aerosol-generating article may have an upstream end through which air enters the article during use. An aerosol-generating article may have a downstream end through which air or aerosols are discharged during use.

[0163] As used herein, the term "electrical insulation" means that at room temperature (20 degrees Celsius) and 50% relative humidity, in at least one direction, e.g., all directions, 0.8 × 10⁻⁶. 4 It may refer to materials with an electrical conductivity of less than Siemens / meter.

[0164] As used herein, the term "conductive" means that at room temperature (20 degrees Celsius) and 50% relative humidity, at least 0.8 × 10⁻¹⁰ in at least one direction, e.g., all directions. 6It can sometimes refer to a material with an electrical conductivity of Siemens / meter.

[0165] As used herein, the term “thermal conductivity” may refer to a material having a thermal conductivity of at least 5, 10, 20, 50, or 100 watts / meter Kelvin in at least one direction, e.g., in all directions, at room temperature (20 degrees Celsius) and 50% relative humidity. [Examples]

[0166] 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 one or more of the features described above, for example, one or more features of other embodiments, forms, or aspects described herein.

[0167] Example 1. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method includes controlling the power supply to one or both of the internal and external heaters during a series of stages, wherein the power supply differs in at least two of the stages, or in each stage. A method comprising, if necessary, one or more or all of the following stages: a preheating stage, a cooling stage, a first stage, and a second stage. Example 2. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method is During the first stage, the power supply to one or both of the internal and external heaters is controlled to raise the temperature of the internal heater during the first stage. A method comprising controlling the power supply to an external heater during a second stage, for example immediately following the first stage, to raise the temperature of the external heater during the second stage. Example 2B. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method is During the first stage, the internal heater is heated to a temperature higher than the first predetermined temperature, or the internal heater is maintained at that temperature. During the first stage, the external heater is heated to a temperature lower than a first predetermined temperature, or the external heater is maintained at that temperature. A method comprising heating an external heater to a temperature higher than a first predetermined temperature during a second stage following a first stage. Example 2C. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method is During the first stage, the internal heater is heated to a temperature exceeding 150 degrees Celsius, or the external heater is maintained at that temperature. During the first stage, the external heater is heated or maintained at a temperature of less than 100 degrees Celsius. During the second stage following the first stage, the external heater is heated to a temperature exceeding 150 degrees Celsius, During the first part of the second stage, which is immediately after the first stage if necessary, the heating of the external heater to 80-130 degrees Celsius, and if necessary, this heating is in response to detecting a first predetermined number of smoke intakes of the system during the current usage session, for example, three, four, five, or six smoke intakes. A method comprising heating an external heater to a temperature of 130-400 degrees Celsius or 160-300 degrees Celsius, during the second part of the second stage, which is after the first part of the second stage, and if necessary immediately after, the second part of the second stage, and if necessary, the heating in response to detecting a second predetermined number of smoke intakes in the system during the current usage session, for example, six, seven, eight, nine, or ten smoke intakes. Example 3. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method is During the preheating stage, the power supply to one or both of the internal and external heaters is controlled to raise the temperature of the internal heater to at least the minimum preheating temperature of the internal heater; After the preheating stage, for example during the subsequent cooling stage, the power supply to one or both of the internal and external heaters is controlled to lower the temperature of the internal heater to a temperature lower than the minimum preheating temperature of the internal heater. The process includes, for example, controlling the power supply to one or both of the internal heater and the external heater during the first stage immediately following the cooling stage to raise the temperature of one or both of the internal heater and the external heater, and any one, two, or all of the following steps: A method that, if necessary, includes a second stage following the first stage, for example, immediately after. Example 4. The method is During the first stage, if necessary, the power supply to the internal heater is increased during the first stage, by controlling the power supply to the internal heater according to the internal heater power supply profile of the first stage, and by controlling the power supply to the external heater according to the external heater power supply profile of the first stage, or both of these. The method according to any one of Examples 1 to 3, comprising controlling the power supply to the internal heater according to the internal heater power supply profile of the second stage, and controlling the power supply to the external heater according to the external heater power supply profile of the second stage, or both, so as necessary, to raise the temperature of the external heater during the second stage. Example 5. The method according to any one of Examples 1 to 4, wherein the internal heater is or includes a susceptor, and the external heater is or includes an inductor such as an inductor coil. Example 6. The method according to Example 5, wherein the method includes controlling the power supply to an external heater according to the external heater power profile of the first stage during the first stage in order to inductively heat the susceptor. Example 7. The method according to any one of Examples 5 to 6, wherein the method includes controlling the power supply to an external heater according to the external heater power supply profile of the second stage during the second stage in order to resistively heat the inductor. Example 8. The method according to any one of Examples 5 to 7, wherein the inductor is heated to a higher temperature during the second stage than during the first stage, for example, by resistance heating. Example 9. The method according to any one of Examples 5 to 8, wherein the peak temperature of the inductor during the second stage is higher than the peak temperature of the inductor during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 10. The method according to any one of Examples 5 to 9, wherein the average temperature of the inductor during the second stage is higher than the average temperature of the inductor during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 11. The method according to any one of Examples 5 to 10, wherein the temperature of the inductor at the end of the second stage is higher than the temperature of the inductor at the start of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Example 12. The method according to any one of Examples 5 to 11, wherein controlling the power supply to the inductor includes controlling one or both of the frequency and magnitude of the alternating current supplied to the inductor. Example 13. The method according to any one of Examples 5 to 12, wherein controlling the power supply to an external heater according to a first-stage external power supply profile includes supplying an alternating current to an inductor at a first frequency. Example 14. The method according to any one of Examples 5 to 13, wherein controlling the power supply to the external heater according to the second stage external heater power supply profile includes supplying an alternating current of a second frequency different from the first frequency to the inductor. Example 15. The method according to any one of Examples 5 to 14, wherein supplying alternating current to the inductor at a first frequency, compared to supplying alternating current to the inductor at a second frequency, results in either or both increased inductive heating of the susceptor and reduced resistive heating of the inductor. Example 16. The method according to any one of Examples 5 to 15, wherein supplying an AC current to an inductor at a second frequency, compared to supplying an AC current to an inductor at a first frequency, results in either or both increased resistance heating of the inductor and reduced inductive heating of the susceptor. Example 17. The method according to any one of Examples 5 to 16, wherein controlling the power supply to the external heater according to the second-stage external heater power supply profile includes supplying DC alone or in combination with AC current to the inductor. Example 18. The method described in any one of Examples 5 to 17, wherein no DC current is supplied to the inductor during the first stage. Example 19. The method according to any one of Examples 1 to 18, wherein the method includes a preheating step. Example 20. The method according to Example 19, wherein the preheating step occurs before the first step or at the start of the first step. Example 21. The method according to Example 19 or 20, wherein the method includes controlling the power supply to the internal heater according to the internal heater power supply profile of the preheating stage, and controlling the power supply to the external heater according to the external heater power supply profile of the preheating stage, or both, during the preheating stage. Example 22. The method according to Example 21, wherein the internal heater power profile during the preheating stage is different from one or both of the internal heater power profile during the first stage and the internal heater power profile during the second stage. Example 23. The method according to Example 21 or 22, wherein the external heater power profile in the preheating stage is different from one or both of the external heater power profile in the first stage and the external heater power profile in the second stage. Example 24. The method according to any one of Examples 19 to 23, wherein substantially no aerosol is formed during the preheating stage. Example 25. The method according to any one of Examples 19 to 24, wherein the internal heater is heated to a higher temperature than the external heater during the preheating stage. Example 26. The method according to any of Examples 19 to 25, wherein the internal heater is heated during the preheating stage, but the external heater is not substantially heated. Example 27. The method according to any one of Examples 19 to 26, wherein no power is supplied to the external heater during the preheating stage. Example 28. The method according to any one of Examples 19 to 27, wherein the peak temperature reached by the internal heater during the preheating stage is greater than or equal to one or both of the peak temperature reached by the internal heater during the first stage and the peak temperature reached by the internal heater during the second stage. Example 29. The method according to any one of Examples 19 to 28, wherein the temperature of the internal heater is at least 200, 300, or 400 degrees Celsius for at least a portion of the preheating stage. Example 30. The method according to any one of Examples 19 to 29, wherein the temperature of the internal heater is 500 or 400 degrees Celsius or less for at least part of the preheating stage. Example 31. The method according to any one of Examples 19 to 30, wherein the temperature of the internal heater is 200 to 500 degrees Celsius, or 200 to 400 degrees Celsius, for at least part of the preheating stage. Example 32. The method according to any one of Examples 19 to 31, wherein the temperature of the external heater is at least 200, 300, or 400 degrees Celsius for at least a portion of the preheating stage. Example 33. The method according to any one of Examples 19 to 32, wherein the temperature of the external heater is 500 or 400 degrees Celsius or less for at least part of the preheating stage. Example 34. The method according to any one of Examples 19 to 33, wherein the temperature of the external heater is 200 to 500 degrees Celsius, or 200 to 400 degrees Celsius, for at least part of the preheating stage. Example 35. The method according to any one of Examples 19 to 34, wherein the preheating step lasts for at least 5, 10, 20, or 30 seconds. Example 36. The method according to any one of Examples 19 to 35, wherein the preheating step lasts for at least 60, 45, or 30 seconds. Example 37. The method according to any of Examples 19 to 36, wherein the preheating step lasts for 5 to 60, 5 to 45, or 10 to 45 seconds. Example 38. The method according to any of Examples 1 to 37, wherein the first step is the aerosol generation step. Example 39. The method described in any one of Examples 1 to 38, wherein the first step is immediately after the preheating step. Example 40. The method according to any one of Examples 1 to 39, wherein the average temperature of the internal heater during the first stage is higher than the average temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 41. The method according to any one of Examples 1 to 40, wherein the peak temperature of the internal heater during the first stage is higher than the peak temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 42. The method according to any of Examples 1 to 41, wherein during the first stage, the internal heater is heated, but the external heater is not substantially heated. Example 43. The method according to any of Examples 1 to 42, wherein no power is supplied to the external heater during the first stage. Example 44. The method according to any one of Examples 1 to 43, wherein the temperature of the internal heater is at least 150, 200, 250, or 300 degrees Celsius for at least part of the first stage. Example 45. The method according to any one of Examples 1 to 44, wherein the temperature of the internal heater is 500, 450, or 400 degrees Celsius or less for at least part of the first stage. Example 46. The method according to any one of Examples 1 to 45, wherein the temperature of the internal heater is 150 to 500 degrees Celsius, or 200 to 450 degrees Celsius, or 250 to 400 degrees Celsius, for at least part of the first stage. Example 47. The method according to any one of Examples 1 to 46, wherein the temperature of the external heater is at least 150, 200, 250, or 300 degrees Celsius for at least part of the first stage, and the temperature of the external heater is 500, 450, or 400 degrees Celsius or less for at least part of the first stage, or both. Example 48. It is a method, The temperature of the external heater is, for at least part of the first stage, above 30 degrees Celsius and below 100 or 150 degrees Celsius, or both. The method according to any one of Examples 1 to 47, wherein the temperature of the external heater is one or both of the following: above 100 or 150 degrees Celsius and below 300 degrees Celsius for at least part of the second stage. Example 49. The method according to any one of Examples 1 to 48, wherein the temperature of the external heater is 150 to 500 degrees Celsius, or 200 to 450 degrees Celsius, or 250 to 400 degrees Celsius, for at least part of the first stage. Example 50. The method according to any of Examples 1 to 49, wherein the first step lasts for at least 60, 90, 120, 150, or 180 seconds. Example 51. The method according to any of Examples 1 to 50, wherein the first step lasts for 360, 300, 270, or 240 seconds or less. Example 52. The method according to any of Examples 1 to 51, wherein the first stage lasts for 60 to 360 seconds, or 60 to 300 seconds, or 90 to 270 seconds. Example 53. The method according to any one of Examples 1 to 52, wherein the first stage lasts for the duration of at least one inhalation, and optionally at least two, three, or five inhalations. Example 54. The method according to any of Examples 1 to 53, wherein the first stage lasts for 10 or 8 or fewer inhalations. Example 55. The method according to any of Examples 1 to 54, wherein the first stage lasts for 1 to 10, or 1 to 8, or 2 to 8, or 3 to 8 puffs. Example 56. The method according to any one of Examples 1 to 55, wherein the temperature of the internal heater is kept constant or rises during the first stage. Example 57. The method according to any one of Examples 1 to 56, wherein the temperature of the internal heater at the end of the first stage is equal to or greater than the temperature of the internal heater at the start of the first stage. Example 58. The method according to any one of Examples 1 to 57, wherein the average temperature of the internal heater during the first part of the first stage, for example the first half, is equal to or greater than the average temperature of the internal heater during the second part of the subsequent first stage, for example the second half. Example 59. The method according to any one of Examples 1 to 58, wherein the temperature of the internal heater rises substantially monotonically, for example continuously, for at least part of the first stage, for example, at least 10, 20, or 50 degrees Celsius. Example 60. The method according to any one of Examples 1 to 59, wherein the temperature of the internal heater is maintained at the first internal heater temperature of the first stage for at least a portion of the first stage. Example 61. The method according to any one of Examples 1 to 60, wherein the temperature of the internal heater is maintained at a first internal heater temperature of the first stage during the first part of the first stage, and then maintained at a second internal heater temperature of the first stage, which is different from the first internal heater temperature of the first stage, during the second part following the first part of the first stage. Example 62. The temperature of the internal heater is maintained at a third internal heater temperature of the first stage, which is different from one or both of the first internal heater temperature of the first stage and the second internal heater temperature of the first stage, during the third stage following the second stage of the first stage. The method according to Example 61. Example 63. The method according to any one of Examples 61 and 62, wherein the second internal heater temperature in the first stage is higher than the first internal heater temperature in the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 64. The method according to any one of Examples 61, 62, and 63, wherein the third internal heater temperature in the first stage is higher than one or both of the first internal heater temperature and the second internal heater temperature in the first stage, for example by at least 20, 50, or 100 degrees Celsius higher. Example 65. The method according to any one of Examples 1 to 64, wherein the temperature of the external heater is kept constant at, for example, 100 to 300 degrees Celsius, or 150 to 300 degrees Celsius, or 200 to 300 degrees Celsius, or rises during at least part of the first stage. Example 66. The method according to any one of Examples 1 to 65, wherein the temperature of the external heater at the end of the first stage is equal to or greater than the temperature of the external heater at the start of the first stage. Example 67. The method according to any one of Examples 1 to 66, wherein the average temperature of the external heater during the first part of the first stage, for example the first half, is equal to or greater than the average temperature of the external heater during the second part of the subsequent first stage, for example the second half. Example 68. The method according to any one of Examples 1 to 67, wherein the temperature of the external heater rises substantially monotonically, for example, continuously, for at least part of the first stage. Example 69. The method according to any one of Examples 1 to 68, wherein the temperature of the external heater is maintained at the first external heater temperature of the first stage for at least a portion of the first stage. Example 70. The method according to any one of Examples 1 to 69, wherein the temperature of the external heater is maintained at a first external heater temperature of the first stage during the first part of the first stage, and then maintained at a second external heater temperature of the first stage, which is different from the first external heater temperature of the first stage, during the second part following the first part of the first stage. Example 71. The temperature of the external heater is maintained at a third external heater temperature of the first stage, which is different from one or both of the first external heater temperature of the first stage and the second external heater temperature of the first stage, during the third stage following the second stage of the first stage. The method according to Example 70. Example 72. The method according to Example 70 or 71, wherein the second external heater temperature in the first stage is higher than the first external heater temperature in the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 73. The method according to Examples 70, 71, or 72, wherein the third external heater temperature in the first stage is higher than one or both of the first external heater temperature and the second external heater temperature in the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 74. The aerosol generating article according to any of Examples 1 to 73, wherein the second step is the aerosol generation step. Example 75. The method according to any of Examples 1 to 74, wherein the second step is immediately following the first step. Example 76. The method according to any of Examples 1 to 75, wherein the external heater is heated during the second stage, but the internal heater is not heated. Example 77. The method according to any of Examples 1 to 76, wherein no power is supplied to the internal heater during the second stage. Example 78. The method according to any one of Examples 1 to 77, wherein the average temperature of the internal heater during the second stage is higher than the average temperature of the external heater during the second stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 79. The method according to any one of Examples 1 to 78, wherein the peak temperature of the internal heater during the second stage is higher than the peak temperature of the external heater during the second stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 80. The method according to any one of Examples 1 to 79, wherein the temperature of the internal heater is at least 150, 200, 250, or 300 degrees Celsius for at least part of the second stage. Example 81. The method according to any one of Examples 1 to 80, wherein the temperature of the internal heater is 500, 450, or 400 degrees Celsius or less for at least part of the second stage. Example 82. The method according to any one of Examples 1 to 81, wherein the temperature of the internal heater is 150 to 500 degrees Celsius, or 200 to 450 degrees Celsius, or 250 to 400 degrees Celsius, for at least part of the second stage. Example 83. The method according to any one of Examples 1 to 82, wherein the temperature of the external heater is at least 150, 200, 250, or 300 degrees Celsius for at least part of the second stage. Example 84. The method according to any one of Examples 1 to 83, wherein the temperature of the external heater is 500, 450, or 400 degrees Celsius or less for at least part of the second stage. Example 85. The method according to any one of Examples 1 to 84, wherein the temperature of the external heater is 150 to 500 degrees Celsius, or 200 to 450 degrees Celsius, or 250 to 400 degrees Celsius, for at least part of the second stage. Example 86. The method according to any one of Examples 1 to 85, wherein the temperature of the external heater at the end of the second stage is lower than 20, 50, or 100 degrees Celsius higher than the temperature of the internal heater at the end of the second stage, and both of the above are higher than 20, 50, or 100 degrees Celsius lower than the temperature of the internal heater at the end of the second stage. Example 87. The method according to any one of Examples 1 to 86, wherein the temperature of the external heater at the end of the second stage is higher than the temperature of the external heater at the start of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Example 88. The method according to any one of Examples 1 to 87, wherein the second step lasts for at least 90, 120, 150, or 180 seconds. Example 89. The method according to any of Examples 1 to 88, wherein the second step lasts for 360, 300, 270, or 240 seconds or less. Example 90. The method according to any of Examples 1 to 89, wherein the second stage lasts for 60 to 360 seconds, or 60 to 300 seconds, or 90 to 270 seconds. Example 91. The method according to any one of Examples 1 to 90, wherein the second stage lasts for the duration of at least one inhalation, and optionally at least two, three, or five inhalations. Example 92. The method according to any one of Examples 1 to 91, wherein the second stage lasts for 10 or 8 or fewer inhalations. Example 93. The method according to any of Examples 1 to 92, wherein the second step lasts for 1 to 10, or 1 to 8, or 2 to 8, or 3 to 8 puffs. Example 94. The method according to any one of Examples 1 to 93, wherein the temperature of the internal heater is kept constant or decreases for at least part of the second stage. Example 95. The method according to any one of Examples 1 to 94, wherein the temperature of the internal heater at the end of the second stage is equal to or less than the temperature of the internal heater at the start of the second stage. Example 96. The method according to any one of Examples 1 to 95, wherein the average temperature of the internal heater during the first part of the second stage, for example the first half, is equal to or greater than the average temperature of the internal heater during the second subsequent part of the second stage, for example the second half. Example 97. The method according to any one of Examples 1 to 96, wherein the temperature of the external heater is kept constant or rises during the second stage. Example 98. The method according to any one of Examples 1 to 97, wherein the temperature of the external heater at the end of the second stage is equal to or greater than the temperature of the external heater at the start of the second stage. Example 99. The method according to any one of Examples 1 to 98, wherein the average temperature of the external heater during the first part of the second stage, for example the first half, is equal to or greater than the average temperature of the external heater during the second subsequent part of the second stage, for example the second half. Example 100. The method according to any one of Examples 1 to 99, wherein the temperature of the external heater rises substantially monotonically, for example, continuously, for at least part of the second stage. Example 101. The method according to any one of Examples 1 to 100, wherein the temperature of the external heater is maintained at the first external heater temperature of the second stage for at least a portion of the second stage. Example 102. The method according to any one of Examples 1 to 101, wherein the temperature of the external heater is maintained at a first external heater temperature of the second stage during the first part of the second stage, and then maintained at a second external heater temperature of the second stage, different from the first external heater temperature of the second stage, during the second part following the first part of the second stage. Example 103. The temperature of the external heater is maintained at a third external heater temperature of the second stage, which is different from one or both of the first external heater temperature of the second stage and the second external heater temperature of the second stage, during the third stage following the second part of the second stage. The method as described in Example 102. Example 104. The method according to Example 102 or 103, wherein the second external heater temperature in the second stage is higher than the first external heater temperature in the second stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 105. The method according to Examples 102, 103, or 104, wherein the third external heater temperature in the second stage is higher than one or both of the first external heater temperature in the second stage and the second external heater temperature in the second stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 106. The method according to any one of Examples 1 to 105, wherein the internal heater power profile of the first stage is different from the internal heater power profile of the second stage, and the external heater power profile of the first stage is different from the external heater power profile of the second stage, or both. Example 107. The method according to any one of Examples 1 to 106, wherein the average temperature of the external heater during the second stage is higher than the average temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 108. The method according to any one of Examples 1 to 107, wherein the peak temperature of the external heater during the second stage is higher than the peak temperature of the external heater during the first stage, for example, by at least 20, 50, or 100 degrees Celsius higher. Example 109. The method according to any one of Examples 1 to 108, wherein the average temperature difference between the internal heater and the external heater during the first stage is greater than the average temperature difference between the internal heater and the external heater during the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Example 110. The method according to any one of Examples 1 to 109, wherein the average temperature difference between the internal heater and the external heater at the start of the second stage is greater than the average temperature difference between the internal heater and the external heater at the end of the second stage, for example, by at least 20, 50, or 100 degrees Celsius. Example 111. The method according to any one of Examples 1 to 110, wherein the average temperature difference between the internal heater and the external heater at either the start or end of the second stage, or both, is greater than 20, 50, or 100 degrees Celsius. Example 112. A method according to Example 1 or 3, or any of Examples 1 to 111 dependent on Example 1 or 3, or any of the other Examples 1 to 111, wherein the method further comprises a preheating step and a cooling step following the preheating step. Example 113. The method according to Example 112, wherein the cooling stage lasts for one or more of the following durations: at least 90, 120, 150, or 180 seconds, 360, 300, 270, or 240 seconds or less, 60 to 360, or 60 to 300, or 90 to 270 seconds, at least one smoke inhalation, optionally at least two, three, or five smoke inhalations, 10 or eight smoke inhalations or less, or a duration of 1 to 10, or 1 to 8, or 2 to 8, or 3 to 8 smoke inhalations. Example 114. The method according to Example 112 or 113, wherein the cooling step is immediately after the preheating step, and the first step is immediately after the cooling step. Example 115. The method according to any one of Examples 112 to 114, wherein during the cooling stage, the temperature of the internal heater is preferably lowered by at least 10, 20, 50, or 100 degrees Celsius from, for example, the minimum preheating temperature of the internal heater. Example 116. The method according to any one of Examples 112 to 115, wherein during the cooling phase, the temperature of the internal heater is reduced to a temperature below 300 or 250 degrees Celsius, and at least 150 or 200 degrees Celsius, or both. Example 117. The method according to any one of Examples 112 to 116, wherein during the cooling stage, the temperature of the external heater is preferably lowered by at least 10, 20, 50, or 100 degrees Celsius from, for example, the lowest preheating temperature of the external heater. Example 118. The method according to any one of Examples 112 to 117, wherein during the cooling phase, the temperature of the external heater is reduced to a temperature below 300 or 250 degrees Celsius, and at least one or both of the following temperatures: 100, 150, or 200 degrees Celsius. Example 119. The method according to any one of Examples 112 to 118, wherein the temperature drop of the internal heater during the cooling phase is greater than the temperature drop of the external heater during the cooling phase. Example 120. The method according to any of Examples 1 to 119 dependent on Example 3, wherein the minimum preheating temperature of the internal heater is at least one of the following: 100, 200, or 300 degrees Celsius, 500 or 400 degrees Celsius or less, and 200 to 500 degrees Celsius, or 200 to 400 degrees Celsius, or 300 to 400 degrees Celsius. Example 121. The method according to any of Examples 1 to 120 dependent on Example 3, wherein the method includes controlling the power supply to an external heater during the preheating stage to raise the temperature of the external heater to at least the minimum preheating temperature of the external heater, and optionally the minimum preheating temperature of the external heater being at least 100, 200, or 300 degrees Celsius, 500 or 400 degrees Celsius or less, and one or more of 100 to 500 degrees Celsius, or 100 to 400 degrees Celsius, or 100 to 300 degrees Celsius, or 200 to 500 degrees Celsius, or 200 to 400 degrees Celsius, or 200 to 300 degrees Celsius. Example 122. The method according to any of Examples 1 to 121, which are dependent on Example 3, wherein during the first step, the power supply to one or both of the internal heater and the external heater is controlled to raise the temperature of one or both of the internal heater and the external heater to one or more of the following: raising the temperature of the internal heater to at least 200, 250, or 300 degrees Celsius, and raising the temperature of the external heater to at least 150 or 200 degrees Celsius. Example 123. The method according to any one of Examples 1 to 122, wherein the second stage is triggered by a predetermined number of fume extractions of an aerosol-forming substrate during the current use session, for example, two, three, four, or five fume extractions of the aerosol-forming substrate during the current use session, or by the elapsed time since the first fume extraction of the aerosol-forming substrate, or by the activation of an internal or external heater, for example, by the elapsed time since the initial activation, or by the elapsed time since the internal or external heater reached a predetermined temperature, or by the start of a preheating stage, the end of a preheating stage, or by the elapsed time since the start of the first stage, or by the activation of a user-activatable trigger, or by any one or more of these options. Example 124. An aerosol generating device for use as part of an aerosol generating system, wherein the aerosol generating system is Aerosol generator and an aerosol generating article comprising an aerosol-forming substrate, It comprises an internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, Aerosol generator, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, Equipped with a controller, The controller An aerosol generator configured to control the power supply to one or both of an internal heater and an external heater during multiple stages, wherein the power supply differs in at least two of the multiple stages, or in each stage. Example 125. The aerosol generator according to Example 124, wherein the device is equipped with an internal heater. Example 126. The aerosol generator according to Example 124, wherein the article is equipped with an internal heater. Example 127. The aerosol generation system An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, Equipped with a controller, The controller An aerosol generating system configured to control the power supply to one or both of an internal heater and an external heater during multiple stages, wherein the power supply differs in at least two of the stages, or in each stage. Example 128. The aerosol generating system according to Example 127, wherein the controller is configured to perform the method described in any one of Examples 1 to 127 of the Method. Example 129. An aerosol generating system according to any one of Examples 127 to 128, wherein the system comprises an aerosol generator, and if necessary, the aerosol generator is the aerosol generator described in any one of Examples 124 to 126. Example 130. An aerosol generating system according to any one of Examples 127 to 129, wherein the system comprises an aerosol generating article containing an aerosol forming substrate. Example 131. An aerosol generating system according to any one of Examples 127 to 128, comprising an aerosol generator, optionally an aerosol generator according to any one of Examples 124 to 126, and an aerosol generating article, wherein the aerosol generator is configured to engage with and, for example, accept at least a portion of the aerosol generating article. Example 132. An aerosol generating system according to any one of Examples 127 to 122, wherein the device is equipped with an external heater. Example 133. An aerosol generating system according to any one of Examples 127 to 132, wherein the device is equipped with an internal heater. Example 134. An aerosol generating system according to any one of Examples 127 to 132, wherein the article is equipped with an internal heater. Example 135. An aerosol generating system according to any of Examples 127 to 131, wherein the device comprises an internal heater, the device comprises an external heater, the internal heater is a susceptor or includes a susceptor, and the external heater is an inductor such as an inductor coil or includes one. Example 136. An aerosol generating system according to any of Examples 127 to 131, wherein the device comprises an external heater, the article comprises an internal heater, the internal heater is or includes a susceptor, and the external heater is or includes an inductor such as an inductor coil. Example 137. An aerosol generating system according to any one of Examples 127 to 131, wherein the device is equipped with an internal heater, the device is equipped with an external heater, the internal heater is an electrical resistance heater, and the external heater is an electrical resistance heater. Example 138. An aerosol generating system according to any one of Examples 127 to 131, wherein the device comprises an internal heater, an external heater, an inductor different from the external heater, the external heater is an electrical resistance heater, and the internal heater is a susceptor, or includes the same. Example 139. An aerosol generating system according to any of Examples 127 to 131, wherein the device comprises an external heater, the device comprises an inductor different from the external heater, the article comprises an internal heater, the external heater is an electrical resistance heater, and the internal heater is a susceptor or includes the same.

[0168] Here, we will further describe the examples with reference to the figures. [Brief explanation of the drawing]

[0169] [Figure 1] Figure 1 shows a side cross-sectional view of an aerosol generator according to the first embodiment. [Figure 2] Figure 2 shows an axial cross-sectional view along line 1-1 of the aerosol generator of Figure 1. [Figure 3] Figure 3 shows a side cross-sectional view of an aerosol generation system comprising the aerosol generator of Figure 1. [Figure 4] Figure 4 shows a side cross-sectional view of an aerosol generator according to a second embodiment. [Figure 5] Figure 5 shows a side cross-sectional view of an aerosol generation system comprising the aerosol generator of Figure 4. [Figure 6] Figure 6 illustrates a possible form of an inductor coil for the devices of Figures 1-5. [Figure 7] Figure 7 illustrates the provision of a thermal bridging element between the inductor coil and the aerosol generating article. [Figure 8] Figure 8 is a block diagram showing the inductive heating arrangement of the aerosol generator described in connection with Figures 1-5. [Figure 9A] Figure 9A is a schematic diagram showing the electronic components of a first embodiment of the electrical circuit of the aerosol generator described in connection with Figures 1-5. [Figure 9B] Figure 9B is a schematic diagram showing a second embodiment of the electrical circuit of the aerosol generator described in connection with Figures 1-5. [Figure 10] Figure 10 illustrates an AC current supply for a first method of controlling an aerosol generation system according to the first or second embodiment. [Figure 11] Figure 11 illustrates a DC current supply for a first method of controlling an aerosol generation system according to the first or second embodiment. [Figure 12] Figure 12 illustrates the temperature profiles over time of the internal heater and the external heater of an aerosol generation system according to the first or second embodiment when controlled according to the first method. [Figure 13] Figure 13 illustrates an AC current supply for a second method of controlling an aerosol generation system according to the first or second embodiment. [Figure 14]Figure 14 illustrates a DC current supply for a second method of controlling an aerosol generation system according to the first or second embodiment. [Figure 15] Figure 15 illustrates the temperature profiles over time of the internal and external heaters of the aerosol generation system according to the first or second embodiment, when controlled according to the second method. [Figure 16] Figure 16 illustrates an AC current supply for a third method of controlling an aerosol generation system according to the first or second embodiment. [Figure 17] Figure 17 illustrates a DC current supply for a third method of controlling an aerosol generation system according to the first or second embodiment. [Figure 18] Figure 18 illustrates the temperature profiles over time of the internal and external heaters of the aerosol generation system according to the first or second embodiment, when controlled according to the third method. [Figure 19] Figure 19 shows a side cross-sectional view of an aerosol generator according to the third embodiment. [Figure 20] Figure 20 shows a side cross-sectional view of an aerosol generator according to the fourth embodiment. [Figure 21] Figure 21 shows a side cross-sectional view of an aerosol generator according to the fifth embodiment. [Figure 22] Figure 22 shows the temperature profiles over time for the internal and external heaters of the aerosol generation system. [Figure 23] Figure 23 shows the temperature profiles over time for the internal and external heaters of the aerosol generation system. [Figure 24] Figure 24 shows the temperature profiles over time for the internal and external heaters of the aerosol generation system. [Modes for carrying out the invention]

[0170] Figures 1 and 2 show an aerosol generator 10 according to a first embodiment. The device 10 comprises a housing 12 that defines a chamber 16 for receiving a portion of an aerosol generating article. The chamber 16 comprises an open end 18 through which the aerosol generating article may be inserted into the chamber 16, and a closed end 20 opposite the open end 18. The cylindrical wall 22 of the chamber 16 extends between the open end 18 and the closed end 20.

[0171] The apparatus 10 also includes an external heater in the form of an inductor coil 24, which includes a plurality of windings 26 placed inside the chamber 16. The plurality of windings 26 of the inductor coil 24 define a tubular space 28 that receives a portion of the aerosol-generating article when the aerosol-generating article is inserted into the chamber 16. Advantageously, positioning the inductor coil 24 in direct contact with the aerosol-generating article received inside the chamber 16 facilitates the transfer of heat generated by the resistive heating of the inductor coil 24 to the aerosol-generating article.

[0172] The inductor coil 24 comprises a first end 30 positioned toward the open end 18 of the chamber 16 and a second end 32 positioned toward the closed end 20 of the chamber 16. Each of the first end 30 and the second end 32 is housed within a portion of the cylindrical wall 22 of the chamber 16, holding the inductor coil 24 within the chamber 16. The cylindrical wall 22 of the chamber 16 can define first and second recesses, slots, or openings that receive the first end 30 and the second end 32 of the inductor coil 24, respectively. Alternatively, the first end 30 and the second end 32 of the inductor coil 24 may be fixed to the cylindrical wall 22 of the chamber 16 by overmolding the housing 12 over the first end 30 and the second end 32 of the inductor coil 24 during the manufacturing of the housing 12.

[0173] The inductor coil 24 is suspended within the chamber 16 by its first end 30 and second end 32 such that the winding 26 of the inductor coil 24 is spaced apart from the cylindrical wall 22 of the chamber 16. Thus, the inductor coil 24 contacts the housing 12 only at its first end 30 and second end 32. By spaced the winding 26 of the inductor coil 24 apart from the cylindrical wall 22 of the chamber 16, an annular gap 34 is defined between the cylindrical wall 22 of the chamber 16 and the winding 26 of the inductor coil 24. Advantageously, the annular gap 34 reduces or minimizes the transfer of heat generated by the resistive heating of the inductor coil 24 to the housing 12. Advantageously, the annular gap 34 facilitates airflow through the chamber 16 when an aerosol-generating article is received inside the chamber 16.

[0174] To facilitate the insertion of an aerosol-generating article into the chamber 16, the inductor coil 24 is arranged concentrically around the central axis 36 of the device 10. To ensure secure placement of the inductor coil 24 within the chamber 16, the first end 30 and the second end 32 of the inductor coil 24 are held by diametrically opposed portions of the cylindrical wall 22 of the chamber 16.

[0175] The housing 12 also defines a number of projections 38 extending into the chamber 16 from the closed end 20 of the chamber 16. As will be further described below, the number of projections 38 function to maintain a gap between the end of the aerosol-generating article and the closed end 20 of the chamber 16 when the aerosol-generating article is fully inserted into the chamber 16. In the embodiments shown in Figures 1 and 2, the housing 12 defines three projections 38 that are equidistant from the central axis 36 of the device 10. Those skilled in the art will understand that the housing 12 may define more or fewer projections 38, and that the arrangement of the projections 38 at the closed end 20 of the chamber 16 may be modified.

[0176] The aerosol generating device 10 also includes a controller or control circuit 40 connected to the inductor coil 24, and a power supply 42. The control circuit 40 is configured to control the power supply from the power supply 42 to the inductor coil 24. Specifically, the control circuit 40 is configured to supply an alternating current from the power supply 42 to the inductor coil 24 to generate an alternating magnetic field within the chamber 16.

[0177] Figure 3 is a cross-sectional view of an aerosol generation system 100 including the device 10 of FIG. 1 and an aerosol generating article 102.

[0178] The article 102 includes an aerosol-forming substrate 104 in the form of a tobacco plug, a first hollow acetate tube 106, a second hollow acetate tube 108, a mouthpiece 110, and an outer wrapper 112. The article 102 also includes an internal heater in the form of a susceptor element 114 disposed within the aerosol-forming substrate 104.

[0179] In use, a portion of the article 102 is inserted into the chamber 16 and the inductor coil 24 such that the aerosol-forming substrate 104 and the susceptor element 114 are disposed within the tubular space 28 defined by the inductor coil 24. The control circuit 40 supplies an alternating current from the power supply 42 to the inductor coil 24 to generate an alternating magnetic field that inductively heats the susceptor element 114, which heats the aerosol-forming substrate 104 to generate an aerosol. As will be described in more detail below, the level of inductive coupling between the inductor coil 24 and the susceptor element 114 (and as a result, the heating of the susceptor 114) is affected by the frequency of the alternating current supplied to the inductor coil 24.

[0180] The airflow through the system 100 in use is illustrated by the dashed line 116 in Figure 3. When a user inhales the mouthpiece 110 of the article 102, negative pressure is generated in the chamber 16. This negative pressure draws air into the chamber 16 through the open end 18 of the chamber. The air entering the chamber 16 then flows through the annular gap 34 between the inductor coil 24 and the cylindrical wall 22 of the chamber 16. When the airflow reaches the closed end 20 of the chamber 16, the air enters the article 102 through the aerosol-forming substrate 104. The airflow into the article 102 is facilitated by the gap maintained between the upstream end of the article 102 and the closed end 20 of the chamber 16 by a plurality of protrusions 38. As the airflow passes through the aerosol-forming substrate 104, the aerosol generated by the heating of the aerosol-forming substrate 104 is taken into the airflow. The aerosol then flows along the length of the article 102 and through the mouthpiece 110 to the user.

[0181] Figure 4 shows a cross-sectional view of the aerosol generator 150 according to the second embodiment. The device 150 is similar to the device 10 described with reference to Figures 1 and 2, and the same reference numerals are used to indicate similar parts.

[0182] Apparatus 150 differs from apparatus 10 in that it has an additional internal heater in the form of a susceptor element 164. The susceptor element 164 has an elongated shape and extends into the chamber 16 from the closed end 20 of the chamber 16. The susceptor element 164 extends along the central axis 36 of apparatus 150 such that the inductor coil 24 extends concentrically around the susceptor element 164.

[0183] Figure 5 is a cross-sectional view of an aerosol generating system 170 comprising the apparatus 150 and aerosol generating article 172 shown in Figure 4. System 170 is similar to system 100 described with reference to Figure 3, and the same reference numerals are used to indicate similar parts.

[0184] System 170 differs from system 100 in that it does not have an internal heater in the form of a susceptor element within the article 172. When the article 172 is inserted into the chamber 16, the susceptor element 164 of the apparatus 150 is received into the aerosol-forming substrate 104 of the article 172. Figures 4 and 5 show the susceptor element 164 having a pin-shaped or blade-shaped profile, thereby facilitating the penetration of the aerosol-forming substrate 104 by the susceptor element 164 during the insertion of the article 172 into the chamber 16 of the apparatus 150. Those skilled in the art will understand that the susceptor element 164 may have a profile other than the one shown in Figures 4 and 5. Thus, both systems 100 and 170 have internal and external heaters, but in system 100 of Figure 3, the article 102 has an internal heater in the form of a susceptor element 114, whereas in system 170 of Figure 5, the apparatus 150 has an internal heater in the form of a susceptor element 164. Once article 172 is inserted into chamber 16, the operation of system 170 is identical to the operation of system 100 described with reference to Figure 3.

[0185] Figure 6 illustrates possible coil structures for the devices shown in Figures 1 to 5.

[0186] The first coil structure is shown as coil structure A. Coil structure A comprises a sleeve 400. The helical coil section 410 is formed by removing material from the sleeve 400.

[0187] The insulating material may be placed in the gap where the material of the sleeve 400 has been removed. This may have the advantage of structurally reinforcing the coil structure and may also facilitate the insertion of the aerosol-generating article. Alternatively, a layer of insulating material, such as polyimide tape, may be wound around or overmolded around the helical coil section 410 or sleeve 400. This does not significantly hinder the transfer of heat to the aerosol-generating article, but may improve the structural stability of the coil structure.

[0188] A second coil structure, indicated as coil structure B, comprises a sleeve 500 similar to coil structure A, including a helical coil section 510 obtained by material removal. The sleeve 500 comprises a downstream extension 550 used to connect the sleeve to the housing 12 of the chamber 16 of the apparatus. The extension 550 comprises a through-hole 520 to allow airflow through the sleeve into the aerosol-generating article.

[0189] The third coil structure, coil structure C, comprises a sleeve 600 having a helical coil section 610 and a downstream extension region 650, which has through-holes 620 that are larger in size and number than the through-holes 520 of coil structure B. Compared to coil structure B, the larger openings 620 offer the advantage of reducing the mass of the structure and thus significantly reduce heat loss caused by heat conduction toward the end region of the sleeve.

[0190] While all the devices described so far use helical coils, other forms of inductor coils can be used. Specifically, one or more flat spiral coils or pancake coils can be used to both generate an alternating magnetic field within the chamber 16 and provide external heating from the resistance heating of the coils themselves. Such flat spiral coils may be shaped conformally to the sidewalls of the chamber and may be arranged to generate a magnetic field perpendicular to the longitudinal axis of the chamber.

[0191] While all the devices described so far use helical coils, other forms of inductor coils can be used. Specifically, one or more flat spiral coils or pancake coils can be used to both generate an alternating magnetic field within the chamber and provide external heating from the resistance heating of the coils themselves. Such flat spiral coils may be shaped conformally to the sidewalls of the chamber and may be arranged to generate a magnetic field perpendicular to the longitudinal axis of the chamber.

[0192] Figure 7 shows a cross-sectional view of the aerosol generator 250 according to a third embodiment. The device 250 is similar to the device 150 described with reference to Figures 4 and 5, and the same reference numerals are used to indicate similar parts.

[0193] The embodiment in Figure 7 differs from the embodiments in Figures 4 and 5 in the position of the inductor coil 224 and the provision of a thermal bridging element 228 between the coil 224 and the aerosol generating article 172. The inductor coil 224 is embedded or recessed within the housing of the apparatus 250, and the thermal bridging element 228, formed from a thermally conductive material, is positioned in contact with the inductor coil 224. The thermal bridging element 228 is in the form of an austenitic steel tube. The thermal bridging element 228 partially defines the cylindrical wall of the chamber, which extends between the open and closed ends of the chamber. The thermal bridging element 228 is positioned so that the aerosol generating article 172 is received within the thermal bridging element 228 and is in direct contact with the thermal bridging element 228 when the article is inserted into the chamber. Advantageously, the direct contact between the thermal bridging element 228 and the aerosol generating article 172 facilitates the transfer of heat from the thermal bridging element 228 to the aerosol generating article.

[0194] The inductor coil 224 comprises multiple windings extending around the outer surface of the thermal bridging element 228. The inductor coil 224 is arranged such that the multiple windings are in direct contact with the outer surface of the thermal bridging element 228. Advantageously, arranging the inductor coil 224 in direct contact with the outer surface of the thermal bridging element 228 facilitates the transfer of heat generated by the resistive heating of the inductor coil 224 to the thermal bridging element 228. The inductor coil 224 and the thermal bridging element 228 are arranged concentrically around the central axis of the device 250.

[0195] Here, we will explain in detail the control of the devices described in Figures 1 to 7.

[0196] Figure 8 is a block diagram illustrating an exemplary configuration of components and circuits for generating and supplying alternating current to the inductor coils of an aerosol generator, for example, the inductor coils 24 and 224 of the aerosol generators 10, 150, and 250 in Figures 1, 4, and 7. A DC power supply 310 is connected to a heating arrangement 320. The heating arrangement 320 includes a controller 330, a DC / AC converter 340, a matching circuit 350, and an inductor 240. The DC power supply 310 in Figure 8 corresponds to the power supply 42 of the aerosol generators 10, 150, and 250 in Figures 1, 4, and 7. The controller 330, DC / AC converter 340, and matching circuit 350 correspond to the control circuit 40 of the aerosol generators 10, 150, and 250 in Figures 1, 4, and 7. The inductor coil 240 corresponds to the inductor coils 24 and 224 of the aerosol generators 10, 150, and 250 in Figures 1, 4, and 7. The DC power supply 310 is configured to supply DC power to the heating arrangement 320. Specifically, the DC power supply 310 is configured to supply a DC supply voltage VDC and a DC current IDC to the DC / AC converter 340. The power supply 310 is preferably a battery, such as a lithium-ion battery. Alternatively, the power supply 310 may be another form of charge storage device, such as a capacitor. The power supply 310 may require recharging. For example, the power supply 310 may have sufficient capacity to allow continuous generation of aerosol for about six minutes, or for a time that is a multiple of about six minutes. In another example, the power supply 310 may have sufficient capacity to allow a predetermined number of fume extractions or discontinuous startups of the heating arrangement.

[0197] The DC / AC converter 340 is configured to supply a high-frequency alternating current to the inductor coil 240. As used herein, the term “high-frequency alternating current” means an alternating current having a frequency of about 500 kilohertz to about 30 megahertz. The high-frequency alternating current may have a frequency of about 1 megahertz to about 30 megahertz (e.g., about 1 megahertz to about 10 megahertz, or about 5 megahertz to about 8 megahertz).

[0198] FIG. 9A schematically illustrates a first embodiment of an electric circuit for use in supplying electrical energy to an inductor coil 240. The DC / AC converter 340 preferably comprises a class E power amplifier. The class E power amplifier includes a transistor switch 1320 including a field effect transistor 1321, for example a metal oxide semiconductor field effect transistor, a transistor switch supply circuit indicated by an arrow 1322 for supplying a switching signal (gate-source voltage) to the field effect transistor 1320, and an LC load circuit 1323 including a shunt capacitor C1 and a series connection of a capacitor C2 and an inductor coil L2. The inductor coil L2 corresponds to the inductor coil 240 of FIG. 8. Further, a DC power supply 11 including a choke inductor L1 is shown for supplying a DC supply voltage V DC and a DC current I DC is drawn from the DC power supply 11 during operation. An ohmic resistor R represents a total ohmic load 1324, which is the sum of the ohmic resistor R coil of the inductor coil L2 and the ohmic resistor R load of the susceptor element. The DC power supply 11 corresponds to the DC power supply 310 of FIG. 8.

[0199] The transistor switch supply circuit 1322 can supply a rectangular waveform switching voltage to the field effect transistor 1321. As long as the field effect transistor 1321 is conducting (in the "on" state), a substantially short circuit (low resistance) is formed, so that the entire current flows through the choke L1 and the field effect transistor 1321. When the field effect transistor 1321 is not conducting (in the "off" state), the field effect transistor 1321 basically represents an open circuit (high resistance), so that the entire current flows into the LC load circuit 1323. Switching the field effect transistor 1321 between the conducting ("on") state and the non-conducting ("off") state converts the supplied DC voltage V DC and DC current I DC into an AC voltage V AC and an AC current I AC flowing in the inductor coil L2 having a frequency f.

[0200] In the alternative operating mode, the transistor switch supply circuit 1322 is not operating, so the supplied DC current I DC It remains a direct current and is not converted to AC current.

[0201] Therefore, the circuit in Figure 9A has an AC current I AC or DC current I DC This allows supply to one of the inductor coils L2, but AC and I DC Not both simultaneously.

[0202] Figure 9B schematically illustrates a second embodiment of an electrical circuit used to supply electrical energy to the inductor coil 240. The circuit in Figure 9B includes all the components of the circuit in Figure 9A, but also includes additional circuits. These additional circuits are discussed below.

[0203] A DC power supply is provided to the inductor coil L2. S It is connected to the inductor coil L2 via transistor switch 1326. An additional choke inductor L3 is connected to the DC power supply DC S It is placed between and capacitor C2.

[0204] The transistor switch 1326 is driven by the transistor switch supply circuit indicated by arrow 1325 to supply the switching signal (gate-source voltage). DC source DC S This may be a battery, or any means generally capable of generating DC current. In particular, the battery may be a DC voltage V supplied to the DC / AC converter 340 to generate AC current IAC. DC The same power supply that generates the switch may also be used. When switch 1326 is activated, DC current DC2 The current flows through inductors L3 and L2.

[0205] The choke inductor L3 controls the AC current I AC DC power source DC SIt has the specific purpose of preventing current from flowing through it. For this purpose, advantageously, the inductance value of L3 is significantly higher than the inductance of the inductor coil L2. Similarly, the choke inductor L1 is used when AC current flows through the DC source V DC It is not permitted to flow within it.

[0206] The circuit in Figure 9B shows a) AC current I flowing through capacitor C2, inductor coil L2, and capacitor C1. AC (V DC a) DC current I through inductor L3 and inductor coil L2 (generated by), as well as b) DC current I DC2 This allows for simultaneous or alternating flow of DC current I DC2 Due to the presence of capacitor C2, the signal does not reach the choke inductor L1, and this is I DC2 It is considered an open circuit by this means.

[0207] The circuit can also operate without the choke inductor L3, as long as it is configured to operate sequentially with AC and DC currents (i.e., AC and DC are not started simultaneously).

[0208] As will be explained in detail below, AC current I AC If the frequency is such that there is almost no coupling to the susceptor element, the AC current I AC It is also possible to resistively heat the inductor coil L2. Furthermore, adding a capacitor C3 in parallel with the inductor coil L2 can sometimes be advantageous. In this way, the inductor coil L2 becomes more frequency selective. As explained below, the presence of capacitor C3 allows for frequency f susceptor From frequency f inductor coilSwitching to this configuration significantly improves the process of changing from internal heating to external heating as a result of the AC current, because the difference between the two frequency values ​​can be drastically reduced. In this way, the control may be performed more smoothly. Without capacitor C3, the two frequency values ​​may be far apart from each other, slowing down the system's response.

[0209] Although the DC / AC converter 340 is exemplified as including a Class E power amplifier, the DC / AC converter 340 may use any suitable circuit for converting DC current to AC current. For example, the DC / AC converter 340 may include a Class D power amplifier including two transistor switches. As another example, the DC / AC converter 340 may include a full-bridge power inverter having four switching transistors acting in pairs.

[0210] Returning to Figure 8, the inductor coil 240 may receive AC current from the DC / AC converter 340 via a matching circuit 350 for optimal suitability to the load, although the matching circuit 350 is not mandatory. The matching circuit 350 may comprise a small matching transformer. The matching circuit 350 may improve the power transfer efficiency between the DC / AC converter 340 and the inductor coil 240.

[0211] As shown in Figures 1, 4, and 7, the inductor coils 24 and 224 are arranged around the cavity 16 of the aerosol generators 10, 150, and 250. Therefore, during the operation of the devices 10, 150, and 250, the high-frequency alternating current I supplied to the inductor coils 24 and 224 ACThe inductor coil generates a high-frequency alternating magnetic field within the cavity 16 of the devices 10, 150, and 250. The alternating magnetic field preferably has a frequency of 1 to 30 megahertz, preferably 2 to 10 megahertz, for example, 5 to 7 megahertz. As can be seen from Figures 3, 5 and 7, when the aerosol-generating articles 102 and 172 are inserted into the cavity 16, the aerosol-forming substrate 104 of the articles is positioned adjacent to the inductor coils 24 and 224 so that the susceptor elements 114, 164, and 264 are placed within this alternating magnetic field. When the alternating magnetic field penetrates the susceptor elements 114, 164, and 264, the alternating magnetic field causes the susceptor elements to heat up. For example, eddy currents are generated within the susceptor elements 114, 164, and 264 that are consequently heated. Further heating is provided by magnetic hysteresis losses within the susceptor elements 114, 164, and 264.

[0212] Similarly, the inductor coils 24 and 224 themselves receive a DC current I DC2 by (and / or AC current I AC When resistive heating occurs, the heat is transferred to articles 102 and 172 positioned adjacent to the inductor coils 24 and 224.

[0213] The heated susceptor elements 114, 164, 264 and / or heated inductor coils 24, 224 heat the aerosol-forming substrate 104 of articles 102, 172 to a temperature sufficient to form an aerosol. The aerosol is drawn downstream through articles 102, 172 and is inhaled by the user.

[0214] The controller 330 may be a microcontroller, preferably a programmable microcontroller. The controller 330 is programmed to regulate the power supply from the DC power supply 310 to the induction heating arrangement 320 in order to control the temperature of the susceptor element.

[0215] Figures 10 to 12 illustrate possible methods for controlling the power supply to external heaters or inductor coils 24, 224, 240 in a system such as that shown in Figure 3, Figure 5, or Figure 7. Such methods can be implemented using the control circuit of Figure 9B. Figure 10 shows how the controller 40 controls the supply of AC current IAC to the inductor coils 24, 224, 240 during a time t that includes a first stage between time t0 and time t1, and a subsequent second stage between time t1 and time t2. Figure 11 shows how the controller 40 controls the supply of DC current IDC to the inductor coils 24, 224, 240 during a time t. Figure 12 shows how the temperature T, in particular the temperature Tin of the internal heaters or susceptors 114, 164, 264, and the temperature Tex of the external heaters or inductor coils 24, 224, 240, changes during a time t.

[0216] As shown in Figures 10-12, prior to time t0, no AC or DC current is supplied to the inductor coils 24, 224, 240, and the internal heater temperature Tin and the external heater temperature Tex are both stable at room temperature T0. At time t0, the preheating stage, which is part of the first stage of this embodiment, begins. In other similar embodiments, the preheating stage may be considered separate from the first stage, in which case the first stage can be considered to begin at the end of the preheating stage at time tx. At time t0, an AC current of first amplitude and first frequency is supplied to the inductor coils 24, 224, 240. The first amplitude is relatively large, and the first frequency is selected to maximize the coupling between the inductor coils 24, 224, 240 and the susceptors 114, 164, 264, and thus maximize the heating of the susceptors 114, 164, 264. As a result, the susceptors 114, 164, and 264 rapidly raise their temperature to a preheating stage temperature of approximately 380 degrees Celsius. There is little to no resistance heating of the inductor coils 24, 224, and 240 during the preheating stage. As a person skilled in the art will understand, there may be a slight delay time between the change in the power supply to the heater and the resulting change in the heater temperature. However, for the purposes of this description and the associated figures, a momentary change in the power supplied to the heater may be considered to result in a momentary change in the heater temperature. For the purposes of this specification and the associated figures, a temperature change over a period of less than approximately 5 seconds may be considered momentary. During the first or second stage, neither the internal nor the external heater exceeds the preheating stage temperature. At time tx, the preheating stage ends. The preheating stage is relatively short, about 30 seconds, and little to no aerosol is formed during the preheating stage because the aerosol-forming substrate takes time to warm up to form aerosols, and because the user has not yet started smuggling in systems 100, 170, and 270. At the end of the preheating phase, devices 10, 150, and 250 may notify the user, for example, by audible, visual, or tactile notification, that systems 100, 170, and 270 are ready for smoke extraction.

[0217] At time tx, the controller 40 adjusts the amplitude of the AC current supplied from the power supply 42 to the inductor coils 24, 224, and 240 from a first amplitude to a second amplitude. The second amplitude is smaller than the first amplitude. The frequency does not change. Therefore, the induction heating of the susceptors 114, 164, and 264 is reduced, and the susceptors 114, 164, and 264 drop to a temperature of approximately 300 degrees Celsius. This AC current is maintained from time tx to time ta. During this time, which can last for about 1 minute, the susceptors 114, 164, and 264 are held at approximately 300 degrees Celsius, and the susceptors 114, 164, and 264 heat the aerosol-forming substrate 104, mainly the innermost part of the aerosol-forming substrate 104 to produce an aerosol, or vapor that cools and condenses to form an aerosol. The user can inhale the articles 102, 172 of systems 100, 170, 270, resulting in an airflow as described above and illustrated by the dashed line 116 in Figures 3, 5, and 7, and the resulting aerosol can be inhaled. In this embodiment, the susceptors 114, 164, 264 are maintained at approximately 300 degrees Celsius simply by maintaining a constant AC current supplied to the inductor coils 24, 224, 240. However, as those skilled in the art will understand after reading this disclosure, in other embodiments, the temperature of the susceptors 114, 164, 264 can be maintained at a substantially constant temperature by determining or estimating the temperature of the susceptors 114, 164, 264 using a temperature detector, and then maintaining the temperature of the susceptors 114, 164, 264 accordingly by adjusting one or both of the amplitude and frequency of the AC current supplied to the inductor coils 24, 224, 240.

[0218] At time ta, the controller 40 adjusts the amplitude of the AC current supplied from the power supply 42 to the inductor coils 24, 224, and 240 from the second amplitude to the third amplitude. The frequency does not change. The third amplitude is greater than the second amplitude. Thus, the susceptors 114, 164, and 264 are further inductively heated, and their temperature rises to approximately 320 degrees Celsius. This AC current is maintained from time ta to time tb. During this time, which can last for about 1 minute, the susceptors 114, 164, and 264 are held at approximately 320 degrees Celsius. Heat propagates outward from the susceptors 114, 164, and 264, and comparing time tx and ta, a little more of the inner portion of the aerosol-forming substrate is sufficiently heated to form an aerosol, or vapor, which will later cool and condense in the airflow to form an aerosol. The user can inhale the articles 102 and 172 of systems 100, 170, and 270, thereby generating an airflow as described above and illustrated by the dashed line 116 in Figures 3, 5, and 7, and inhaling the formed aerosol.

[0219] At time tb, the controller 40 adjusts the amplitude of the AC current supplied from the power supply 42 to the inductor coils 24, 224, and 240 from the third amplitude to the fourth amplitude. The frequency does not change. The fourth amplitude is greater than the third amplitude. Thus, the susceptors 114, 164, and 264 are further inductively heated, and their temperature rises to approximately 340 degrees Celsius. This AC current is maintained from time tb to time t1. During this time, which can last for about 1 minute, the susceptors 114, 164, and 264 are held at approximately 340 degrees Celsius. The heat propagates outward from the susceptors 114, 164, and 264, and comparing time ta and tb, a little more of the inner portion of the aerosol-forming substrate is sufficiently heated to form an aerosol, or vapor, which will later cool and condense in the airflow to form an aerosol. The user can inhale the articles 102 and 172 of systems 100, 170, and 270, resulting in an airflow as described above and illustrated by the dashed line 116 in Figures 3, 5, and 7, and the formed aerosol can be inhaled. By time t1 at the end of the first stage, most of the inner portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol and is therefore consumed. Most of the outer portion of the aerosol-forming substrate 104, especially the outermost portion, has not been heated to a temperature sufficient to form an aerosol and is therefore not consumed.

[0220] At time t1, the first stage ends and the second stage begins. At time t1, the controller 40 adjusts the amplitude and frequency of the AC current supply from the power supply 42 to the inductor coils 24, 224, and 240. Both this amplitude and frequency are reduced. This greatly reduces the inductive coupling between the inductor coils 24, 224, and 240 and the susceptors 114, 164, and 264, and thereby greatly reduces the inductive heating of the susceptors 114, 164, and 264, so that the temperature Tin of the susceptors 114, 164, and 264 gradually decreases during the process of the second stage from time t1 to time t2. Furthermore, this AC current supply results in some resistive heating of the external heaters (inductor coils 24, 224, and 240). As those skilled in the art will understand after reading this disclosure, in some embodiments, the controller 40 can completely stop supplying AC current to the inductor coils 24, 224, and 240 during the second stage. This will cause the temperatures of susceptors 114, 164, and 264 to decrease more rapidly during the second phase.

[0221] Also, at time t1, under the control of controller 40, a DC current is supplied from power supply 42 to inductor coils 24, 224, and 240. This DC current increases substantially instantaneously at time t1, and then increases substantially linearly from time t1 to time t2. Thus, the temperature Tex of the external heater (temperature of inductor coils 24, 224, and 240) rises substantially instantaneously at time t1 due to the AC and DC currents, and then rises almost linearly during the second stage from time t1 to time t2 due to the linear increase in the DC current, reaching a final temperature of approximately 320 degrees Celsius at time t2. During the second stage, which can last about 3 minutes, heat propagates inward from the external heater, or inductor coils 24, 224, and 240. As the second stage progresses, a little more of the outer portion of the aerosol-forming substrate is sufficiently heated to form an aerosol, or vapor, which will later cool and condense in the airflow to form an aerosol. The user can inhale the articles 102 and 172 of systems 100, 170, and 270, resulting in an airflow as described above and illustrated by the dashed line 116 in Figures 3, 5, and 7, and the formed aerosol can be inhaled. By time t2 at the end of the second stage, most of the outer portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol and is therefore consumed. Thus, once the inner and outer portions of the substrate 104 are consumed, the substrate is substantially completely consumed. By time t2 at the end of the second stage, the temperature Tex of the external heater is within 50 degrees Celsius of the temperature Tin of the internal heater, and slightly lower.

[0222] As those skilled in the art will understand after reading this disclosure, another possible method for controlling the power supply to the external heater or inductor coils 24, 224, 240 would be similar to that shown in Figure 10, where no DC current is supplied. Such a method can be implemented, for example, using the control circuit shown in Figure 9A. In this case, the temperatures of the internal and external heaters can be adjusted as desired by changing the frequency and amplitude of the AC current. For example, the AC current between times t0 and t1 may be the same as that shown in Figure 10, and one or both of the amplitude and frequency of the AC current supplied to the external heater between times t1 and t2 may be gradually adjusted as the second stage progresses so that the temperature profiles Tin and Tex are similar to or even identical to those shown in Figure 12.

[0223] As a person skilled in the art will understand after reading this disclosure, embodiments similar to those illustrated in Figures 10-12 are possible, where the temperature Tin of the internal heater can be controlled to decrease gradually over a period of time, for example, from time tx to time ta, rather than rapidly decreasing over time tx. In such a case, the period between time tx and time ta can be considered a cooling phase, and the first phase can be considered to begin at time ta.

[0224] Figures 13-15 illustrate a second possible method for controlling the power supply to an external heater or inductor coils 24, 224, 240 in a system such as that shown in any of Figures 3, 5, or 7 (showing devices 100, 150, and 250 in Figures 1, 4, or 7, respectively). Such a method can be implemented, for example, using the control circuit of Figure 9B. Figure 13 shows how the controller 40 controls the supply of AC current to the inductor coils 24, 224, 240 during a time t that includes a preheating phase between times t0 and tx, a first phase between times tx and time t1, and a second phase between times t1 and time t2. Figure 14 shows how the controller 40 controls the supply of DC current IDC to the inductor coils 24, 224, 240 during the same time t. Figure 15 shows what the temperature T, in particular the temperature Tin of the internal heaters or susceptors 114, 164, and 264, and the temperature Tex of the external heaters or inductor coils 24, 224, and 240 are during the same time t.

[0225] As shown in Figures 13-15, before time t0, no AC or DC current is supplied to inductor coils 24, 224, and 240, and both the internal heater temperature Tin and the external heater temperature Tex are stable at room temperature T0.

[0226] At time t0, in this embodiment, the preheating phase, which occurs before the first phase, begins. In other similar embodiments, the preheating phase may be considered part of the first phase, in which case the first phase can be considered to begin at time t0. At time t0, an AC current of first amplitude and first frequency is supplied to the inductor coils 24, 224, 240. The first frequency is selected to maximize the inductive coupling between the inductor coils 24, 224, 240 and the susceptors 114, 164, 264, and thus maximize the heating of the susceptors 114, 164, 264. This causes the susceptors 114, 164, 264 to rapidly raise their temperature to a preheating phase temperature of approximately 380 degrees Celsius. During the first or second phase, neither the internal nor the external heaters exceed the preheating phase temperature. There is little to no resistive heating of the inductor coils 24, 224, 240 during the preheating phase. At time tx, the preheating phase is completed. The preheating phase is relatively short, about 30 seconds, and little to no aerosol is formed during the preheating phase because the aerosol-forming substrate takes time to warm up to form aerosols, and because the user has not yet started smoke extraction in systems 100, 170, and 270. At the end of the preheating phase, devices 10, 150, and 250 may notify the user that systems 100, 170, and 270 are ready for smoke extraction, for example, using audible, visual, or tactile notifications.

[0227] At time tx, the first stage begins, and the controller 40 adjusts the frequency of the AC current supplied from the power supply 42 to the inductor coils 24, 224, and 240 from the first frequency to the second frequency. The second frequency is lower than the first frequency, resulting in weaker inductive coupling between the inductor coils 24, 224, and 240 and the susceptors 114, 164, and 264 than at the first frequency. Consequently, there is less inductive heating of the susceptors 114, 164, and 264, causing them to drop to a temperature of approximately 300 degrees Celsius. This AC current is maintained during the first stage from time tx to time t1, and during the second stage from time t1 to time t2. During this time, which can last for about 5 minutes, the susceptors 114, 164, and 264 are held at approximately 300 degrees Celsius. This AC current between time tx and time t2 may also result in some resistive heating of the external heaters (inductor coils 24, 224, and 240).

[0228] Furthermore, at time tx, which marks the start of the first stage, the controller 40 supplies DC current from the power supply 42 to the inductor coils 24, 224, and 240. This DC current is held constant for approximately one minute, and then increased at time ta. The further increase in DC current and the holding period for one minute are repeated at times tb, tc, and td. The DC current resistively heats the external heater, or inductor coils 24, 224, and 240. Thus, the temperature Tex of the external heater follows a similar pattern to that of the DC current. The temperature Tex of the external heater is approximately 100 degrees Celsius between time tx and time ta, approximately 160 degrees Celsius between time ta and time tb, approximately 220 degrees Celsius between time tb and time tc, approximately 280 degrees Celsius between time tc and time td, and approximately 340 degrees Celsius between time td and time t2. Each of these periods lasts for approximately one minute. In this embodiment, the second stage can be considered to begin, for example, at time t1 between time ta and tb.

[0229] As a result, in this embodiment, the temperature of the internal heaters and susceptors 114, 164, and 264 is kept substantially constant during the first and second stages, while the temperature of the external heaters and inductor coils 24, 224, and 240 rises in five steps during the first and second stages.

[0230] During the first and second stages, the user can inhale the articles 102 and 172 of systems 100, 170, and 270, resulting in an airflow as described above and illustrated by the dashed line 116 in Figures 3, 5, and 7, and the formed aerosol can be inhaled.

[0231] During the first stage, the internal heaters and susceptors 114, 164, and 264 heat the inner portion of the substrate to form an aerosol. As the first stage progresses, heat propagates outward from the internal heaters, heating more of the substrate, but the outer portion of the substrate is not heated sufficiently to form a sufficient amount of aerosol. By time t1 at the end of the first stage, most of the inner portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol, which is then consumed.

[0232] During the second stage, the external heater is at a reasonably high temperature. The external heater, with some help from the internal heater, heats the outer portion of the substrate to form an aerosol. As the second stage progresses, the external heater temperature increases in stages, thereby further transferring heat inward from the external heater, heating more of the substrate to form an aerosol. By time t2 at the end of the second stage, most of the outer portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol and is therefore consumed. Thus, once the inner and outer portions of the substrate 104 are consumed, the substrate is substantially completely consumed at the end of the second stage.

[0233] As a person skilled in the art will understand after reading this disclosure, embodiments similar to those illustrated in Figures 13-15 are possible, where the internal heater temperature Tin is controlled to decrease gradually over a period of time tx, for example, from time tx to time ta, rather than rapidly decreasing over time tx. In such a case, the period between time tx and time ta can be considered a cooling phase, and the first phase can be considered to begin at time ta.

[0234] Figures 16-18 illustrate a third possible method for controlling the power supply to an external heater or inductor coils 24, 224, 240 in a system such as that shown in any of Figures 3, 5, or 7. Such a method can be implemented, for example, using the control circuit shown in Figure 9B.

[0235] The first stage begins at time t0 and ends at time t1, 3 minutes after t0. The second stage begins at time t1 and ends at time t2, 3 minutes after t1. There is no preheating stage.

[0236] An AC current is supplied to the inductor coils 24, 224, and 240 during the first and second stages between time t0 and time t2. The frequency and amplitude of this AC current do not change. The frequency of the AC current is selected to maximize the heating of the susceptors 114, 164, and 264. Thus, with an internal heater temperature Tin, the temperature of the susceptors 114, 164, and 264 rises substantially instantaneously to the operating temperature at time t0 and is then kept substantially constant for the remainder of the first and second stages. In this embodiment, this operating temperature is approximately 320 degrees Celsius. There is little to no resistive heating of the inductor coils 24, 224, and 240 during the first stage.

[0237] A DC current is supplied to inductor coils 24, 224, and 240 during a second phase between time t1 and time t2. The amplitude of this DC current rises instantaneously to a non-zero value at time t1, and then increases linearly from the first non-zero value at time t1 to a second, larger value at time t2. The external heater temperature Tex (temperature of inductor coils 24, 224, and 240) follows a similar pattern, rising from room temperature T0 to approximately 200 degrees Celsius within a few seconds after t1, and then rising substantially linearly to approximately 300 degrees Celsius at time t2.

[0238] As those skilled in the art will understand after reading this disclosure, the power supplied to the heaters can be controlled in many different ways to provide many different desirable temperature profiles over time for the internal and external heaters. The temperature of the external heaters (inductor coils 24, 224, 240) may be controlled by controlling one or both of the AC current and DC current supplied to the external heaters (inductor coils 24, 224, 240). The temperature of the internal heaters (susceptors 114, 164, 264) may be controlled by controlling the AC current supplied to the external heaters (inductor coils 24, 224, 240). Controlling the AC current may include controlling one or both of the amplitude and frequency. This may make it possible to adjust one or both of the inductive heating of the internal heaters (susceptors 114, 164, 264) and the resistance heating of the external heaters (inductors 24, 224, 240). The control circuit or controller may be configured to control the supply of AC and DC currents by controlling switches 1320 and 1326 shown in Figure 9. This may allow the controller to follow a specific desired temperature profile for the internal and external heaters over time. Advantageously, in the control method, for example, the method illustrated in Figures 10 to 18, the internal heater sufficiently heats the inner portion of the substrate to form an aerosol during the first stage, and then the external heater sufficiently heats the outer portion of the substrate to form an aerosol during the second stage. Also advantageously, the temperature of the external heater rises as the second stage progresses, and as a result, heat propagates inward from the outermost portion of the substrate, sufficiently heating more of the substrate and forming an aerosol. Advantageously, by the end of the second stage, most of the inner and outer portions of the substrate are sufficiently heated and can form an aerosol.

[0239] Figure 19 shows an aerosol generating system 1900 according to a third embodiment. The aerosol generating system 1900 comprises an aerosol generating device 1910 and an aerosol generating article 172, as shown in Figures 5 and 7.

[0240] Apparatus 1910 appears similar to apparatus 170 shown in Figures 4 and 5, but the inductor coil and susceptor element are replaced with an electrical resistance external heater and an electrical resistance internal heater, respectively, as will be described in more detail below. The controller 40 and power supply 42 of apparatus 170 are present in apparatus 1910 but are not visible in Figure 19. Similar reference numerals are used to indicate similar parts, and only the differences are described herein.

[0241] The device 1910 does not have an inductor coil. Instead of an inductor coil, the device 1910 has an electrically resistive external heater 1924. The external heater 1924 comprises a substantially tubular, electrically insulated substrate and a conductive track on the electrically insulated substrate. The controller 40 is configured to resistively heat the external heater 1924 when in use by controlling the supply of power from the power supply 42 to the external heater 1924, in particular by controlling the supply of current through the conductive track.

[0242] The apparatus 1910 also does not have a susceptor element. Instead of a susceptor element, the apparatus 1910 has an electrically resistive internal heater 1914. The internal heater 1914 is shaped as a pin, blade, or rod for penetrating the aerosol-forming substrate of an aerosol-generating article inserted into the chamber of the apparatus 1910. The internal heater 1914 comprises a substantially blade-shaped electrically insulated substrate and a conductive track on the electrically insulated substrate. The controller 40 is configured to resistively heat the internal heater 1914 of the apparatus 1910 when in use by controlling the supply of power from the power supply 42 to the internal heater 1914, in particular by controlling the supply of current through the conductive track.

[0243] As a person skilled in the art will understand after reading this disclosure, the controller 40 can control the power supply to the internal heater 1714 and the external heater 1724 to provide the temperature profiles shown in any of Figures 12, 15, and 18. Furthermore, as a person skilled in the art will understand after reading this disclosure, the apparatus 1910 may have two power supplies connected to the controller 40, one for supplying power to the internal heater 1914 and the other for supplying power to the external heater 1924.

[0244] Figure 20 shows an aerosol generating system 2000 according to a fourth embodiment. The system 2000 comprises an aerosol generating device 2010 and an aerosol generating article 172, as shown in Figures 5 and 7.

[0245] Apparatus 2010 appears similar to apparatus 170 shown in Figures 4 and 5, but as will be explained in more detail below, the inductor coil does not act as an external heater. Rather, a separate electrically resistive heating element is introduced. The controller 40 and power supply 42 of apparatus 170 are present in apparatus 2010 but are not visible in Figure 20. Similar reference numbers are used to indicate similar parts, and only the differences are described herein.

[0246] Similar to the apparatus 170 shown in Figures 4 and 5, the apparatus 2010 shown in Figure 20 comprises a susceptor element 164 and an inductor coil 24 for inductively heating the susceptor element 164.

[0247] However, in the embodiment shown in Figure 20, the inductor coil 24 is located within the housing of the device 2010. Furthermore, the inductor coil 24 does not act as an external heater. Instead, the device includes an electrically resistive external heater 2024. In some embodiments, the external heater 2024 is identical to the external heater 1924 shown in Figure 19. However, in the embodiment shown in Figure 20, the external heater 2024 comprises a polymer material and at least one of graphite, graphite-derived material, and hexagonal boron nitride dispersed within the polymer material. The polymer material includes at least one of polyetheretherketone (PEEK) and liquid crystal polymer (LCP). The external heater 2024 contains the polymer material in an amount of 27 weight percent of the external heater, but this amount may be 22 percent to 33 percent. The graphite-derived material includes at least one of expanded graphite and graphite nanoplatelets. The external heater contains at least one of graphite, graphite-derived material, and hexagonal boron nitride in an amount of 65 weight percent of the external heater, although this may be 62 to 69 percent. The external heater further contains additives dispersed in a polymer material, carbon black. The external heater contains additives in an amount of 7 weight percent of the external heater, although this may be 5 to 9 percent. The external heater 2024 is not an inductively heatable material and has no interaction with the alternating magnetic field generated by the inductor 24 during use, or only negligible interaction.

[0248] The controller 40 is configured to control the power supply from the power supply 42 to the external heater 2024 to heat the external heater 2024. The controller 40 is also configured to control the power supply from the power supply 42 to the inductor coil 24, in particular by controlling the supply of alternating current to the inductor coil 24 to generate an alternating magnetic field in the chamber, thereby inductively heating the susceptor element 164 (internal heater) of the device 2010 when in use.

[0249] As a person skilled in the art will understand after reading this disclosure, the controller 40 can control the power supply to the external heater 2024 and the inductor 24 to provide the temperature profiles shown in any of Figures 12, 15, and 18. Furthermore, as a person skilled in the art will understand after reading this disclosure, the apparatus 2010 may have two power supplies connected to the controller 40, one for supplying power to the internal heater 2014 and the other for supplying power to the external heater (inductor coil 24).

[0250] Figure 21 shows an aerosol generating system 2100 according to the fourth embodiment. The aerosol generating system 2100 comprises the aerosol generating device 2110 and the aerosol generating article 102 shown in Figure 3.

[0251] The aerosol generating article 2110 is similar to the aerosol generating device 100 shown in Figures 1 and 3. The controller 40 and power supply 42 of device 100 are present in device 2110 but are not visible in Figure 21. Similar reference numerals are used to indicate similar parts, and only the differences are described herein.

[0252] Similar to the apparatus 100 shown in Figures 1 and 3, the apparatus 2110 shown in Figure 21 includes an inductor coil 24.

[0253] However, in the embodiment shown in Figure 20, the inductor coil 24 is located within the housing of the device 2110. Furthermore, the inductor coil 24 does not act as an external heater. Instead, the device 2110 includes an external heater 2124, which has electrical resistance similar to the external heater in the embodiment shown in Figure 19. The external heater 2124 comprises a substantially tubular, electrically insulated substrate and conductive tracks on the electrically insulated substrate.

[0254] The controller 40 is configured to control the power supply from the power supply 42 to the external heater 2124, in particular by controlling the supply of current through the conductive track to heat the external heater 2124. The controller 40 is also configured to control the power supply from the power supply 42 to the inductor coil 24, in particular by controlling the supply of alternating current to the inductor coil 24 to generate an alternating magnetic field in the chamber, thereby inductively heating the susceptor element 114 (internal heater) of the aerosol generating article 102 when in use.

[0255] As a person skilled in the art would understand after reading this disclosure, the controller 40 can control the power supply to the external heater 2124 and the inductor 24 to provide the temperature profile shown in any of Figures 12, 15, and 18. Furthermore, as a person skilled in the art would understand after reading this disclosure, the apparatus 2110 may have two power supplies connected to the controller 40, one for supplying power to the inductor coil 24 and the other for supplying power to the external heater 2124.

[0256] Figure 22 illustrates, similar to Figures 12, 15, and 18, another possible method for controlling the power supply in an aerosol generating system having an internal heater and an external heater, illustrating the temperature profiles of the internal and external heaters as a graph of temperature T against time t. The aerosol generating system may be any aerosol generating system described herein, for example, any system illustrated in Figures 3, 5, 7, 19, 20, or 21.

[0257] In the embodiment illustrated in Figure 22, there is a preheating stage from time t0 to tz, a cooling stage from time tz to tx, and a first stage from time tx to t1. There is no second stage. The temperature Tin of the internal heater and the temperature Tex of the external heater are shown between these stages. The temperature Tin of the internal heater is shown by a solid line, and the temperature Tex of the external heater is shown by a dotted line.

[0258] Before time t0, which is the time when a system usage session can be considered to have started in response to a user activating the system, the internal and external heaters are at room temperature T0.

[0259] At time t0, the start of the preheating phase, the internal and external heater temperatures rise as quickly as possible to minimize the time required for the user to start the system and generate aerosols for the user's first smoke inhalation. The internal heater temperature Tin rises to approximately 350 degrees Celsius. The external heater temperature Tex rises to approximately 240 degrees Celsius. These temperatures are then maintained for approximately 20 seconds until time tz, when the preheating phase ends and the cooling phase begins.

[0260] At time tz, which marks the start of the cooling phase, the system may indicate to the user that the system is ready to begin smoke extraction, and the user may begin smoke extraction. Also at time tz, the power supplied to the heater is reduced or stopped to gradually lower the heater temperature.

[0261] From time tz to time tx, the temperature Tin of the internal heater decreases from approximately 350 degrees Celsius to approximately 250 degrees Celsius.

[0262] Approximately halfway through the time interval from time tz to time tx, the temperature Tex of the external heater drops from approximately 240 degrees Celsius to approximately 200 degrees Celsius. Then, for the remainder of the time until tx, the temperature Tex of the external heater is maintained at approximately 200 degrees Celsius.

[0263] The cooling phase may last for about 1 or 2 minutes. During this time, the user may inhale smoke and aerosols from the system, for example, as described in more detail for the systems in Figures 3, 5, 7, 19, 20, and 21. Advantageously, the cooling during the cooling phase allows sufficient aerosol generation to satisfy the user without consuming so much aerosol-forming substrate in the first few inhalations of the user's usage session that there is little aerosol-forming substrate left unconsumed for later inhalation.

[0264] At time tx, which marks the start of the first stage, the temperature of the internal heater is controlled to gradually increase from approximately 250 degrees Celsius at time tx to approximately 300 degrees Celsius at time t1, in this case, a linear increase. During the first stage, the temperature of the external heater is kept constant at approximately 200 degrees Celsius. The first stage may last for about 4-5 minutes, during which time the user may extract smoke with the system as desired. Advantageously, during the first stage, the temperature Tin of the internal heater increases to ensure that sufficient aerosol generation occurs during subsequent smoke extraction, even though some of the aerosol-forming substrate is consumed during the preceding smoke extraction.

[0265] As those skilled in the art will understand after reading this disclosure, the temperature Tex of the external heater can also be increased during the first stage. This can advantageously assist in aerosol generation during subsequent fume extraction.

[0266] Furthermore, as those skilled in the art will understand after reading this disclosure, the temperature Tex of the external heater can be raised, for example, from 200 degrees Celsius to 250 degrees Celsius in one minute up to time t1. In this case, this embodiment can be considered to have a second stage that begins at or immediately before the time the temperature of the external heater is raised (i.e., one minute before or immediately before time t1).

[0267] Figure 23 illustrates another possible method for controlling the power supply in an aerosol generating system having an internal heater and an external heater, similar to Figures 12, 15, 18, and 22, showing the temperature profiles of the internal and external heaters as a graph of temperature T against time t. This method is consistent with the first preferred method described above in this application. The aerosol generating system may be any aerosol generating system described herein, for example, any system illustrated in Figures 3, 5, 7, 19, 20, or 21.

[0268] In the embodiment illustrated in Figure 23, there is a preheating stage from time t0 to tz, a cooling stage from time tz to tx, a first stage from time tx to time t1, and a second stage from t1 to t2. The temperature Tin of the internal heater and the temperature Tex of the external heater are shown between these stages. The temperature Tin of the internal heater is shown by a solid line, and the temperature Tex of the external heater is shown by a dotted line.

[0269] Prior to time t0, which is the time at which a system usage session can be considered to have started in response to a user activating the system, the internal and external heaters are at room temperature T0.

[0270] At time t0, which marks the start of the preheating phase, the user starts the system. The objective during the preheating phase is to raise the temperature of both the internal and external heaters as quickly as possible. However, to avoid the need to supply power to both the internal and external heaters simultaneously from the power source, which could require an excessively large battery, the internal heater is prioritized for the first 3 seconds of the preheating phase. After these first 3 seconds, the power source alternates between supplying power to the internal heater and supplying power to the external heater multiple times per second. Thus, after the first 3 seconds of the preheating phase, the internal heater Tin is slightly cooled while power is supplied to the external heater, and the external heater is slightly cooled when power is supplied to the internal heater. This cooling and heating appears as a "noise band" in the graph shown in Figure 23, but these small temperature perturbations have been removed for clarity. However, as can be seen from Figure 23, the heating rate of the internal heater decreases slightly when the power source alternates between heating the internal heater and heating the external heater. The internal heater temperature Tin reaches approximately 200 degrees Celsius in the first 3 seconds of the preheating phase. Within the next few seconds, the internal heater temperature Tin reaches approximately 250 degrees Celsius, and the external heater temperature Tex reaches approximately 80 degrees Celsius. The controller aims to maintain these temperatures for the remainder of the preheating phase, which lasts a total of approximately 20 seconds, until the cooling phase begins at time tz.

[0271] At time tz, which marks the start of the cooling phase, the system may indicate to the user that the system is ready to begin fume extraction, and the user may begin fume extraction. Also at time tz, the power supplied to the internal heater is controlled to lower the internal heater temperature Tin. From time tz to time tx, the internal heater temperature Tin decreases from approximately 250 degrees Celsius to approximately 190 degrees Celsius. From time tz to time tx, the external heater temperature Tex is maintained at approximately 80 degrees Celsius.

[0272] The cooling phase may last for approximately one minute. During this time, the user may smoke and inhale the aerosol through the system, for example, as described in more detail for the systems in Figures 3, 5, 7, 19, 20, and 21. Advantageously, the preheating phase and the subsequent cooling phase allow for rapid aerosol generation for the first smoke inhalation and avoid consuming such a large amount of aerosol-forming substrate during the first two smoke inhalations that there is little aerosol-forming substrate left over for later smoke inhalations.

[0273] At time tx, the first stage begins. From time tx to time t2, that is, throughout the entire first and second stages, the power to the internal heater is controlled to maintain the internal heater's temperature Tin at approximately 190 degrees Celsius.

[0274] From time tx to t1, i.e., during the first stage, the temperature of the external heater is kept constant at approximately 80 degrees Celsius. The first stage may last for approximately 2 minutes, during which time the user may use the system to extract smoke as desired.

[0275] At time t1, the second stage begins. In this embodiment, the start of the second stage is triggered by the elapsed time of 3 minutes and 20 seconds from the first startup of the system (corresponding to 20 seconds for the preheating stage, 1 minute for the cooling stage, and 2 minutes for the first stage). However, the second stage can also be initiated by the detection of a specific smoke extraction in the system during the current usage session, for example, the fourth smoke extraction.

[0276] Between times t1 and t2, the power supplied to the external heater is controlled to raise the external heater temperature Tex at a nearly constant rate until it reaches the maximum allowable temperature, which in this embodiment is approximately 210 degrees Celsius. Specifically, in this embodiment, the external heater temperature rises from approximately 80 degrees Celsius at time t1 to approximately 210 degrees Celsius about 8 minutes after time t1. In this embodiment, time t2 is approximately 9 minutes after time t1. At time t2, the second stage ends, the usage session ends, and the system notifies the user accordingly. Advantageously, during the second stage, the external heater temperature Tex rises from approximately 80 degrees Celsius to approximately 210 degrees Celsius. During the early part of the second stage, the higher temperature of the external heater is advantageous because it means that the internal heater is cooled relatively less by the relatively cold air. This allows the internal heater to continue generating a considerable amount of aerosol from the inner part of the substrate. Next, during the latter part of the second stage, the external heater is hot enough to generate aerosols from the outer part of the substrate, thereby minimizing the amount of substrate wasted.

[0277] In another embodiment, there may be no preheating stage, similar to that shown in Figure 23. Instead, the startup at time t0 may initiate the first stage. Thereafter, upon startup, the controller may heat the internal heater to approximately 190 degrees Celsius and the external heater to 80 degrees Celsius. This may take less than 20 seconds. The system may then notify the user that the system is ready to begin fumigation. The second stage may then be initiated in response to a predetermined time, for example, two or three minutes, from the first startup. Alternatively, the second stage may be initiated in response to the detection of a particular fumigation in the system since startup (i.e., during the current usage session), for example, the third, fourth, fifth, or sixth fumigation. The second stage may be identical to that described with reference to Figure 23.

[0278] Figure 24 illustrates another possible method for controlling the power supply in an aerosol generating system having an internal heater and an external heater, similar to Figures 12, 15, 18, 22, and 23, showing the temperature profiles of the internal and external heaters as a graph of temperature T against time t. Similar to Figure 22, this method is consistent with the first preferred method described above in this application. The aerosol generating system may be any aerosol generating system described herein, for example, any system illustrated in Figures 3, 5, 7, 19, 20, or 21.

[0279] In the embodiment illustrated in Figure 24, there is a preheating stage from time t0 to tz, a cooling stage from time tz to tx, a first stage from time tx to time t1, and a second stage from t1 to t2. The temperature Tin of the internal heater and the temperature Tex of the external heater are shown between these stages. The temperature Tin of the internal heater is shown by a solid line, and the temperature Tex of the external heater is shown by a dotted line.

[0280] Prior to time t0, which is the time at which a system usage session can be considered to have started in response to a user activating the system, the internal and external heaters are at room temperature T0.

[0281] At time t0, which marks the start of the preheating phase, the user starts the system. The objective during the preheating phase is to raise the temperature of both the internal and external heaters as quickly as possible. However, to avoid the need to supply power to both the internal and external heaters simultaneously from the power source, which could require an excessively large battery, the internal heater is prioritized for the first 3 seconds of the preheating phase. After these first 3 seconds, the power source alternates between supplying power to the internal heater and supplying power to the external heater multiple times per second. Thus, after the first 3 seconds of the preheating phase, the internal heater Tin is slightly cooled while power is supplied to the external heater, and the external heater is slightly cooled when power is supplied to the internal heater. This cooling and heating appears as a "noise band" in the graph shown in Figure 24, but these small temperature perturbations have been omitted for clarity. However, as can be seen from Figure 24, the heating rate of the internal heater decreases slightly when the power source alternates between heating the internal heater and heating the external heater. The internal heater temperature Tin reaches approximately 200 degrees Celsius in the first 3 seconds of the preheating phase. Within the next few seconds, the internal heater temperature Tin reaches approximately 250 degrees Celsius, and the external heater temperature Tex reaches approximately 170 degrees Celsius. The system then indicates to the user that the system is ready for smoke extraction, and the user may begin smoke extraction. The controller aims to maintain these temperatures of the internal and external heaters until the first smoke extraction is detected at time tz, at which point the preheating phase ends and the cooling phase begins.

[0282] At time tz, which marks the start of the cooling phase, the power supplied to the internal and external heaters is cut off or dramatically reduced to rapidly lower their temperatures. The temperatures of the internal and external heaters are monitored during this temperature drop. When the internal heater temperature Tin drops from approximately 250 degrees Celsius to approximately 190 degrees Celsius and the external heater temperature Tex drops from approximately 170 degrees Celsius to approximately 110 degrees Celsius, in this embodiment, at approximately time tx, about 60 seconds after time tz, both the end of the cooling phase and the start of the first phase occur.

[0283] During the first stage, power is supplied to the heaters again or increased again so that the temperature Tin of the internal heater is maintained at approximately 190 degrees Celsius and the temperature Tex of the external heater is maintained at approximately 110 degrees Celsius. In this embodiment, the first stage continues until time t1 in which the third fume extraction is detected in the system, but in other embodiments it may be the fourth or fifth fume extraction. Advantageously, the preheating stage, and the subsequent cooling stage, and the first stage allow for rapid aerosol generation for the first fume extraction, while avoiding the consumption of such a large amount of aerosol-forming substrate during the first few fume extractions that there is little aerosol-forming substrate left unconsumed for later fume extraction.

[0284] At time t1, the second phase begins.

[0285] During the second phase, the power supplied to the internal heater acts as a controller to maintain the internal heater's temperature Tin at approximately 190 degrees Celsius.

[0286] During the second phase, the target temperature of the external heater increases in response to each detected smoke extraction. As described above, the first phase ends and the second phase begins when the third smoke extraction is detected in the system. The external heater temperature Tex is maintained at approximately 110 degrees Celsius until the fourth smoke extraction is detected. When the fourth smoke extraction is detected, the target temperature of the external heater increases by approximately 15 degrees Celsius to approximately 125 degrees Celsius. Therefore, the controller controls the power supply to the external heater to raise the external heater temperature Tex to 125 degrees Celsius. Similarly, with each smoke extraction that continues up to the twelfth smoke extraction, the target temperature of the external heater increases by 15 degrees Celsius. Thus, when the twelfth smoke extraction is detected, the target temperature of the external heater Tex rises from 230 degrees Celsius to 245 degrees Celsius. In this embodiment, 245 degrees Celsius is considered the maximum allowable temperature of the external heater. As a result, the target temperature of the external heater is maintained at 245 degrees Celsius for the thirteenth smoke extraction and subsequent extractions. In this embodiment, the fourteenth smoke extraction is the final smoke extraction. In response to the detection of the fourteenth smoke extraction, at time t2, the second stage ends and the system notifies the user that the usage session has ended and that power supply to the internal and external heaters will be stopped.

[0287] Advantageously, during the second phase, the temperature Tex of the external heater increases. During the early part of the second phase, the higher temperature of the external heater is advantageous because it means that the internal heater is cooled relatively less by the relatively cold air. This allows the internal heater to continue generating a considerable amount of aerosol from the inner part of the substrate. Then, during the later part of the second phase, the external heater is hot enough to generate aerosol from the outer part of the substrate, thereby minimizing the amount of substrate wasted.

[0288] For the purposes of this specification and the appended claims, unless otherwise indicated, all numerical values ​​representing quantities, amounts, percentages, etc., should be understood in all instances as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, 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 numerical values ​​that fall within the general standard error to the measured value of the characteristic that the number A modifies. In some instances 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 fundamental and novel characteristics of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. A method for controlling an aerosol generation system, wherein the aerosol generation system is An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, The system comprises an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, The method described above is During the preheating stage, the power supply to one or both of the internal heater and the external heater is controlled to raise the temperature of the internal heater to at least the minimum preheating temperature of the internal heater. During the cooling stage following the preheating stage, the power supply to one or both of the internal heater and the external heater is controlled to lower the temperature of the internal heater to a temperature lower than the minimum preheating temperature of the internal heater. The first step following the cooling step includes controlling the power supply to one or both of the internal heater and the external heater to raise the temperature of one or both of the internal heater and the external heater, A method wherein the average temperature of the external heater during the first part of the first stage is equal to or greater than the average temperature during the subsequent second part of the first stage.

2. The method according to claim 1, wherein the minimum preheating temperature of the internal heater is 200 to 400 degrees Celsius.

3. The method according to any one of claims 1 to 2, wherein the method includes, during the preheating step, controlling the power supply to the external heater to raise the temperature of the external heater to at least the minimum preheating temperature of the external heater, wherein the minimum preheating temperature of the external heater is lower than the minimum preheating temperature of the internal heater and is between 150 and 350 degrees Celsius.

4. The method according to any one of claims 1 to 3, wherein the average temperature of the internal heater during the first portion of the first stage is lower than the average temperature of the internal heater during the second portion of the first stage.

5. The method according to claim 4, wherein the average temperature of the internal heater between the first part of the first stage is 150 to 300 degrees Celsius, the average temperature of the internal heater between the second part of the first stage is 200 to 400 degrees Celsius, and the average temperature of the external heater between the first and second parts of the first stage is both 150 to 250 degrees Celsius.

6. The method described above is During the cooling stage, the power supply to one or both of the internal heater and the external heater is controlled to lower the temperature of the internal heater by at least 50 degrees Celsius. The method according to any one of claims 1 to 5, comprising one or both of the following: controlling the power supply to the external heater during the cooling step to lower the temperature of the external heater by at least 20 degrees Celsius.

7. The method according to any one of claims 1 to 6, wherein the temperature of the external heater is at least 210 degrees Celsius during at least a portion of the preheating stage and the first stage or both.

8. The method according to any one of claims 1 to 7, wherein the method includes controlling the power supply to one or both of the internal heater and the external heater during the first step to raise the temperature of the internal heater to at least 200 degrees Celsius.

9. The method according to any one of claims 1 to 8, wherein the method includes controlling the power supply to the external heater during the first step to raise the temperature of the external heater to at least 150 degrees Celsius.

10. The method according to any one of claims 1 to 9, wherein the method includes controlling the power supply to the external heater to maintain the temperature of the external heater at a constant temperature of 150 to 350 degrees Celsius during at least a portion of the first step.

11. The method according to any one of claims 1 to 10, wherein the cooling step lasts for at least 30 seconds and for at least two smoke extractions in the aerosol generating system, or both.

12. The method according to any one of claims 1 to 11, wherein the first step lasts for at least 30 seconds and for at least two inhalations in the aerosol generating system, or both.

13. The method according to any one of claims 1 to 12, wherein the internal heater comprises a susceptor and the external heater comprises an inductor.

14. An aerosol generating device for use as part of an aerosol generating system, wherein the aerosol generating system is The aerosol generator and, an aerosol generating article comprising an aerosol-forming substrate, The aerosol-forming substrate comprises an internal heater configured to heat the aerosol-forming substrate from within, The aerosol generator, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, Equipped with a controller, An aerosol generator wherein the controller is configured to perform the method according to any one of claims 1 to 13.

15. An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, Equipped with a controller, An aerosol generating system wherein the controller is configured to perform the method according to any one of claims 1 to 13.

16. A method for controlling an aerosol generating system, wherein the aerosol generating system comprises an internal heater configured to heat the aerosol forming substrate from inside the aerosol forming substrate and an external heater configured to heat the aerosol forming substrate from outside the aerosol forming substrate, and the method is During the first stage, the internal heater is heated to a temperature higher than a first predetermined temperature, or the internal heater is maintained at that temperature. During the first step, the external heater is heated to a temperature lower than the first predetermined temperature, or the external heater is maintained at that temperature. A method comprising heating the external heater to a temperature higher than a first predetermined temperature during a second step following the first step.

17. The method according to claim 16, wherein the method includes heating the internal heater to a temperature exceeding 150 degrees Celsius or maintaining the internal heater at a temperature exceeding 150 degrees Celsius during the first step.

18. The method according to claim 16 or 17, wherein the method includes heating the external heater to a temperature below 100 degrees Celsius or maintaining the external heater at a temperature below 100 degrees Celsius during the first step.

19. The method described above is The internal heater is maintained at a temperature exceeding 150 degrees Celsius throughout the entirety of the first stage. The method according to claim 16, 17, or 18, comprising one or both of the following: maintaining the external heater at a temperature below 100 degrees Celsius for the entire duration of the first step.

20. The method, during at least part of the second step, controls the temperature of the external heater or the target temperature. Monotonously or continuously, or The method according to any one of claims 16 to 19, comprising raising the temperature monotonically or continuously until the maximum allowable external heater temperature or a target temperature is reached.

21. The method according to any one of claims 16 to 20, wherein the commencement of the second stage is triggered by detecting that a predetermined number of inhalations have been performed in the system during the current use session, for example, by detecting that two, three, four, five, or six inhalations have been performed in the system during the current use session.

22. The method described above, during the second step, In response to the detection of a first predetermined number of smoke intakes, for example, during the current usage session or during the second stage, the external heater temperature or target temperature is increased. The method according to any one of claims 16 to 21, comprising increasing the temperature of the external heater or a target temperature in response to the detection of a second predetermined number of smoke intakes, for example, during the current usage session or during the second stage.

23. The method according to any one of claims 16 to 21, wherein the method includes heating the external heater to a temperature of 80 to 130 degrees Celsius during the first part of the second step.

24. The method according to claim 23, wherein raising the temperature of the external heater to 80 to 130 degrees Celsius during the first portion of the second stage is in response to detecting a predetermined number of smoke extractions in the system, for example, three, four, five, or six, during the current usage session.

25. The method according to any one of claims 16 to 21, 23, or 24, wherein the method includes raising the temperature of the external heater to a temperature of 130 to 400 degrees Celsius during the second part of the second step.

26. The method according to claim 25, wherein during the second portion of the second stage, the temperature of the external heater is raised to a temperature of 130 to 300 degrees Celsius in response to the system detecting a predetermined number of smoke inhalations, for example, six, seven, eight, nine, or ten smoke inhalations, during the current usage session.

27. The method according to any one of claims 16 to 26, wherein the method includes maintaining the temperature of the internal heater above 150 degrees Celsius during the second step, for example, for the entirety of the second step.

28. The method according to any one of claims 16 to 27, wherein the method includes a preheating step before the first step, and the method includes, at the start of the preheating step, heating the internal heater to a temperature of 100 or 150 degrees Celsius before the external heater is heated to a temperature of 50 or 90 degrees Celsius.

29. An aerosol generating device for use as part of an aerosol generating system, wherein the aerosol generating system is The aerosol generator and, an aerosol generating article comprising an aerosol-forming substrate, The aerosol-forming substrate comprises an internal heater configured to heat the aerosol-forming substrate from within, The aerosol generator, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, an aerosol generator comprising a controller, wherein the controller is configured to perform the method according to any one of claims 16 to 29.

30. An internal heater configured to heat the aerosol-forming substrate from inside the aerosol-forming substrate, An external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, an aerosol generating system comprising a controller, wherein the controller is configured to perform the method according to any one of claims 16 to 29.

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