Aerosol-forming device and system

Abstract

An aerosol-forming device (1) is described, comprising a heating device (6a) configured to heat at least a part of an aerosol-forming substrate (23) or article (20) to form aerosol, wherein the heating device (6a) comprises at least two opposing heating elements (6,7) defining a heating volume (30a) therebetween that is configured to receive at least a part of the aerosol-forming article (20); and control circuitry (5) configured to control a temperature of the heating elements (6,7) during a usage session based on controlling a supply of power from a power source (15) of the aerosol-forming device (1) to the heating device (6a), wherein the control circuitry (5) is configured to increase the temperature of the heating elements (6,7) in a first phase of the usage session from an initial temperature to a first target temperature; decrease the temperature of the heating elements (6,7) in a second phase of the usage session; and increase the temperature of the heating elements (6,7) in a third phase of the usage session.

Description

[0001] AEROSOL-FORMING DEVICE AND SYSTEM

[0002] The present disclosure generally relates to the field of aerosol-forming devices and systems for generating aerosol, also referred to as aerosol-generating devices and aerosol-generating systems. In particular, the present disclosure relates to an electronic aerosol-forming device and an electronic aerosol-forming system configured to generate or form aerosol, for example aerosol inhalable by a user in one or more user inhalations or puffs. Further, the present disclosure relates to a method of controlling or operating an aerosol-forming device or system.

[0003] Aerosol-forming or aerosol-generating devices are typically designed as handheld devices that can be used by a user for consuming or experiencing, for instance in one or more usage sessions, aerosol generated from an aerosol-forming substrate or an aerosol-forming article. Therein, aerosol is typically generated by heating at least a part of the substrate to a certain temperature sufficient to release aerosol from the substate. The aerosol-forming devices the present disclosure pertains to are, in particular, directed to the field of heated tobacco products (HTP), heat-not-burn (HNB) devices, tobacco and tobacco-substitute products. However, the present disclosure is also applicable to other types of inhalers, dispensers, or atomizers, for example inhalers, dispensers, vaporizers or atomizers for medical or pharmaceutical applications.

[0004] Typical aerosol-forming systems can be designed as one-part systems or devices including an aerosol-forming device that can be operated by a user to generate aerosol, for example from a removable or non-removable aerosol-forming article. Alternatively, aerosol-forming systems can be designed as two-part systems or devices comprising an aerosol-forming device and a companion device for storing and / or charging the aerosol-forming device. In either design or configuration, the aerosol-forming system or device can be used by a user for consuming or inhaling, for instance in one or more usage sessions, aerosol generated based on heating an aerosol-forming article or substrate couplable to or at least partly insertable into the aerosolforming system. In the context of the present disclosure, an aerosol-forming device can refer to both a one-part device and a two-part device, unless explicitly specified otherwise.

[0005] The aerosol-forming article, also referred to as aerosol-generating article, can comprise an aerosol-generating or aerosol-forming substrate. Therein, the aerosol-forming substrate may include a solid material, a liquid material, or both liquid and solid material. Exemplary aerosolforming substrates can comprise solid substrate material with one or more ingredients, such as tobacco material, tobacco cast leaves (TCL) material or cannabis-based material.

[0006] The solid, liquid, or a mixed-form of solid and liquid aerosol-forming substrate may contain one or more ingredients, active ingredients or active agents, which may be vaporized during a usage session and inhaled by the user in one or more user inhalations. A user inhalation is synonymously and interchangeably used herein with “puff” of the user. Exemplary ingredients of the aerosol-forming article or substrate include nicotine, nicotine-containing substances, water,aroma, sugar, moisturising agent, botanicals, preservative, flavouring, for example cocoa, liquorice, menthol and lactic acid or other additives or ingredients. Other exemplary ingredients of the aerosol-forming substrate include one or more pharmaceutical agents, one or more drugs, one or more adjuvants or other active agents. Accordingly, the aerosol formed from a corresponding substrate may contain one or more of these ingredients, active ingredients or active agents and / or may be inhalable by the user in one or more user inhalations or puffs.

[0007] The aerosol-forming article may be configured in shape and size to be removably inserted at least partly into the aerosol-forming device or system. In some conventional systems or devices, the aerosol-forming article is usually formed as a stick, cuboid or have another geometry. The aerosol-forming article may be at least partly inserted into a heating volume, heating cavity or heating chamber of the aerosol-forming device for aerosol consumption.

[0008] For generating the aerosol during use or consumption, heat can be supplied by a heating element, heating device, heater arrangement or heat source to heat at least a portion or part of the aerosol-forming substrate. At least a part of the heating device can be arranged in the handheld device or a handheld part of the aerosol-forming device. Alternatively or additionally, at least a part of or the entire heating device can be fixedly associated with or arranged within an aerosol-forming article.

[0009] Exemplary heating elements, heating devices, or heater arrangements can be based on one or more of resistive heating, inductive heating, conductive heating, convective heating, infrared heating or other radiative heating, dielectric heating and microwave heating using electrical energy supplied via, drawn from or stored in an energy storage or battery of the aerosolforming device.

[0010] Typically, aerosol-forming devices comprise an energy storage or power source, for example a rechargeable energy storage, providing the electrical energy needed to operate the aerosol-forming device and especially for heating the aerosol-forming substrate and / or article, for example to generate aerosol in one or more usage sessions using one or more aerosol-forming articles.

[0011] To actually store electrical energy, the energy storage may include one or more battery cells, one or more rechargeable battery cells, one or more accumulators, one or more capacitors or one or more other devices or components for storing electrical energy. Exemplary energy storages may include a plurality of rechargeable battery cells, such as for example between two and ten, preferably between two and four battery cells. Further, exemplary re-chargeable battery cells may be based on lithium-ion battery cells. For example, a cathode material may comprise lithium-cobalt-oxide (LCO), lithium-manganese-oxide (LMO), lithium-nickel-manganese-cobalt-oxide (NMC or NCM), lithium-iron-phosphate (LFP), and / or lithium-nickel-cobalt-aluminum-oxide(NCA). Alternatively or additionally, an anode material may comprise carbon (e.g. graphite), silicon and / or lithium-titanate-oxide (LTO).

[0012] The aerosol-forming device the present disclosure pertains to may, for example, refer to a handheld, battery-powered, lightweight and / or portable device. However, the present disclosure is not limited in this respect, but can be implemented in various forms and designs of aerosolforming devices and systems.

[0013] In the context of the present disclosure, the aerosol-forming device and / or the aerosolforming system may be a portable device and / or system. It may be battery powered. Particularly, the aerosol-forming device and / or the aerosol-forming system may be pocket-size, hand-held, suitable for one-hand use and / or may weigh less than 300 g, preferably less than 200 g. It may be shaped and / or sized to fit snugly into a user’s hand. It may be carried in jacket and / or trouser pockets. Particularly, the aerosol-forming device and / or the aerosol-forming system may be configured to provide aerosol for human inhalation and / or human consumption, particularly inhalation and / or consumption through the mouth.

[0014] As used herein, the term “usage session” may, generally, refer to a period of time, during which a user may use the aerosol-forming device to generate, consume, experience or inhale aerosol. In a single usage session, an aerosol-forming article may be consumed by the user completely or partly. Also, a plurality of aerosol-forming articles may be consumed by the user in a single usage session. Further, the user may take one or more puffs or user inhalations during a usage session. Generally, a usage session may be finite in time. In otherwords, a usage session may have a start, an end and a duration. The duration of the usage session as measured by time may be influenced by use during the usage session. Optionally, the duration of the usage session, for example monitored by a control circuitry of the aerosol-forming device, may have a maximum duration, for example determined by a maximum time from the start of the usage session. The duration of the usage session may be less than the maximum time if one or more monitored parameters reach a predetermined threshold before the maximum time from the start of the usage session. By way of example, the one or more monitored parameters may comprise one or more of: i) a cumulative puff count of a series of puffs drawn by a user since the start of the usage session, and ii) a cumulative volume of aerosol evolved from the aerosol-forming substrate since the start of the usage session. Other parameters can be used instead or in addition.

[0015] As noted above, in the majority of conventional aerosol-forming systems or devices, the aerosol-forming article is formed as a cylindrical stick or has a cylindrical rod-shape. These cylindrical rod-shape aerosol-forming articles are typically designed for use with aerosol-forming devices having tubular cavities or heating chambers. Primarily inductive and resistive heating technologies are used in conventional aerosol-forming devices, however, other heatingtechnologies such as infra-red, microwave, or dielectric heating can also be used to heat the aerosol-forming article for aerosol consumption.

[0016] The cylindrical geometry of conventional aerosol-forming articles, however, may result in non-uniform heat distribution along a radial direction of the cross section of the article, which can be non-favorable or sub-optimal in terms of taste, user experience, and inefficient and limited use of aerosolisable material of the substrate. Apart from the potentially non-uniform heat distribution, insertion of the stick-like shaped aerosol-forming article into the cavity or removal therefrom, can possibly damage the aerosol-forming article, which may be non-favorable in terms of user experience.

[0017] Therefore, it may be desirable to provide for an improved aerosol-forming device, system and corresponding method, which at least partly mitigates or overcomes the drawbacks of conventional systems and devices.

[0018] These advantages may be achieved by the features described herein.

[0019] Aspects of the present disclosure relate to an aerosol-forming device, an aerosol-forming system, and to a method of operating or controlling an aerosol-forming device or system. It is noted that any disclosure presented herein with reference to an or one aspect of the present disclosure, equally applies to any other aspect of the present disclosure, unless explicitly stated otherwise. In particular, it is emphasized that any disclosure presented herein with respect to an aerosol-forming device equally applies to an aerosol-forming system comprising such aerosolforming device and optionally a charger case or companion device, and vice versa.

[0020] According to an aspect, there is provided an aerosol-forming device, also referred to herein as aerosol-generating device, for forming aerosol from an aerosol-forming substrate or article. The aerosol-forming device comprises a heating device configured to heat at least a part of an aerosol-forming substrate or article to form aerosol, wherein the heating device comprises at least two opposing heating elements defining a heating volume therebetween that is configured to receive at least a part of the aerosol-forming article. The two opposing heating elements may be configured to heat the aerosol-forming from two opposing or opposite sides of the substrate or article. The aerosol-forming device further comprises a control circuitry configured to control and / or regulate a temperature of at least one of the heating elements, preferably both heating elements, during a usage session based on controlling a supply of power from a power source of the aerosol-forming device to the heating device. Therein, the control circuitry is configured to:

[0021] increase the temperature of one of or both heating elements in a first phase of the usage session from an initial temperature to a first target temperature;

[0022] decrease the temperature of one of or both the heating elements in a second phase of the usage session; andincrease the temperature of one of or both the heating elements in a third phase of the usage session.

[0023] The two opposing heating elements may be arranged opposite to each other and spaced apart from each other, such that the aerosol-forming article or substrate can be received at least partly in the heating volume and, for example, can be heated from two opposite sides of the aerosol-forming substrate or article. This arrangement or configuration can allow to heat the aerosol-forming substrate, when placed or situated in the heating volume between the two opposing heating elements, uniformly and quickly to generate aerosol for consumption or inhalation by the user. Uniform heating may include or mean that a heat or temperature distribution across the aerosol-substrate may advantageously be uniform in one or more spatial directions, preferably all three spatial directions, for example such that cool areas or spots can be avoided or reduced. In turn, this can improve taste as well as heating efficiency.

[0024] Specifically, the course of the temperature over the three phases of the usage session with the corresponding increases in the first and third phases and the decrease in the second phase, can allow heating the aerosol-forming substrate with a specific temperature gradient that can propagate through the substrate during at least a part of the phases of the usage session. For example, this can allow heating the majority or preferably the entire substrate within a predefined period of time and with a predefined, preferably uniform, heat or temperature distribution in one or more spatial directions of the substrate.

[0025] The two opposing heating elements of the heating device may be spaced apart from each, such that the aerosol-forming article and / or substrate can be accommodated between the two heating elements. For example, the two heating elements may be arranged and configured to contact two opposing sides or faces of the aerosol-forming article, in particular two opposing main faces of the article. This configuration can allow for a rapid and uniform heating of the substrate.

[0026] The two opposing heating elements may generally define a heating chamber or be arranged in a heating chamber of the aerosol-forming device. The heating volume can refer to the space between the two heating elements, where the aerosol-forming article can be placed for aerosol consumption. Accordingly, the heating volume may refer to a part, portion or subspace of the heating chamber.

[0027] The control circuitry, as used herein, may refer to a control means for controlling operation of the heating device, the heating elements of the heating device, optionally the power source or energy storage of the device, and further optionally one or more other functions of the aerosolforming device. The control circuitry may include one or more processors, for example a microcontroller unit (MCU), and / or one or more other data processors. The control circuitry may generally be configured to execute programmed instructions, for example stored in a data storage or memory of the device, to manage the heating process of an aerosol-forming substrate or articlebased on controlling the heating device, controlling a further heating device, controlling power supply to one or both heating elements of the heating device, and / or controlling the power source or energy storage of the aerosol-forming device. The control circuitry may be implemented partly in software and partly in hardware. At least a part of the control circuitry and / or at least a part of its functionalities may be implemented as Application-Specific Integrated Circuit (ASIC), on a printed circuit board with one or more discrete components, as a microcontroller-based implementation, as Field-Programmable Gate Array (FPGA), or hybrid implementation using a combination thereof.

[0028] The “power source” may also be referred to herein as energy storage of the aerosol-forming device or system. The energy storage or power source may be a rechargeable energy storage, providing the electrical energy needed to operate the aerosol-forming device and especially for heating the aerosol-forming substrate and / or article, for example to generate aerosol in one or more usage sessions using one or more aerosol-forming articles. As mentioned above, to actually store electrical energy, the energy storage may include one or more battery cells, one or more rechargeable battery cells, one or more accumulators, one or more capacitors such as supercapacitors or one or more other devices or components for storing electrical energy.

[0029] The initial temperature of the heating elements may refer to the temperature at start of the usage session, for example when the aerosol-forming device is activated by the user in order to be used for aerosol consumption. For example, the initial temperature can substantially correspond to the room or ambient temperature. Alternatively, the initial temperature may also differ from the room or ambient temperature, for example when the device is still at an elevated temperature, because it was recently used by the user.

[0030] Further, the term “target temperature”, for example first, second, third or fourth target temperature, can refer to a temperature of the heating elements that should be reached at least once or at least for an instant of time during the respective phase of the usage session. For example, the target temperature of a particular phase may be reached towards or at the end of the respective phase of the usage session, or may be reached between the start and the end of the respective phase. Also, the temperature of the heating elements in a given phase of the usage session may at least during a part of the respective phase be higher than or lower than the target temperature of the respective phase.

[0031] By heating the heating elements, the temperature of the main faces of the aerosol-forming article and the temperature of the substrate can be increased. Accordingly, a temperature of the heating elements may correspond to or at least be indicative of the temperature of the main faces and / or the substrate of the aerosol-forming article.

[0032] Also, it should be noted that “a temperature of the substrate” may refer to a mean or average temperature of the substrate across its volume or mass, or the temperature of the substrate at atleast one of the main faces. Alternatively or additionally, “a temperature of one or both heating elements” may refer to the average temperature over the volume or heating surface of the heating elements.

[0033] The aerosol-forming article can have a substantially rectangular parallelepiped, oblong and / or cuboid shape defining two opposing main faces and two opposing side faces or lateral faces. The aerosol-forming article may further include an aerosol-forming substrate arranged between the two opposing main faces.

[0034] Optionally, the aerosol-forming article can comprise an air inlet and an air outlet or aerosoloutlet located opposite of each other on the smallest faces of the rectangular parallelepiped shaped aerosol-forming article. The air inlet of the aerosol-forming article may also be referred to herein as upstream air inlet of the article, and the air or aerosol outlet of the article may also be referred to herein as downstream air or aerosol outlet of the aerosol-forming article.

[0035] As used herein, “upstream” may refer to a location that comes before a particular point of reference in the direction of the airflow. Unless specified otherwise, the reference point or location is the heating chamber, heating volume and / or aerosol-forming article, when placed or situated in the heating chamber or volume. For example, an upstream part or element of the device may refer to a part or element where the air comes from before reaching the heating chamber, heating volume and / or aerosol-forming article.

[0036] As used herein, “downstream” may refer to a location that comes after a particular point of reference in the direction of the airflow, in particular after the heating chamber, heating volume and / or aerosol-forming article. For example, a downstream part or element of the device may refer to a part or element where the air goes or flows to after leaving the reference point, in particular the heating chamber, heating volume and / or article.

[0037] The substrate may include primarily solid substrate material. Alternatively or additionally, the aerosol-forming substrate may be a solid substrate. For example, the substrate may include tobacco-based material, herbs, Cannabis-based material, or other solid substrate material. Optionally, however, also moisture, gel, other liquid constituents and / or one or more active ingredients may be comprised in the substrate.

[0038] The heating volume defined by the two opposing heating elements and / or the heating chamber may have a substantially rectangular parallelepiped shape and / or may be configured to receive or removably receive a substantially rectangular parallelepiped shaped aerosol-forming article. For example, the heating chamber and / or heating volume may comprise two opposing main surfaces, which may optionally be substantially flat or planar. Optionally, each of the two main surfaces may be defined or provided by one of the heating elements of the heating device.

[0039] The two heating elements of the heating device can be arranged and configured to heat two opposing main faces of the aerosol-forming article, when the aerosol-forming article is at leastpartly arranged in the heating volume or heating chamber. The heating elements of the heating device may be configured to receive at least a part of the aerosol-forming article and / or substrate therebetween, such that the heating elements contact the two opposing main faces or surfaces of the aerosol-forming article.

[0040] For example, the heating elements of the heating device may be substantially flat or planar. Alternatively or additionally, at least a part of the heating elements may be curved or convex towards respective main face or surface of the aerosol-forming article. The heating elements may be plate-like formed or may comprise a heating structure, for example one or more heating branches or tracks.

[0041] It is noted that the terms “substantially flat or planar” are to be construed broadly herein. Specifically, the terms flat or planar with reference to the heating elements, heating volume or heating chamber may merely mean or include a configuration, design and / or arrangement of one or more of these components to receive a rectangular parallelepiped shaped aerosol-forming article having a rectangular parallelepiped shape. For example, this can mean that the heating elements, heating chamber and / or heating volume is curved or convex towards the aerosolforming article. Also, the two opposing main faces of the aerosol-article may be referred to herein as substantially flat or planar, which can include slightly curved or structured surfaces of the aerosol-forming article.

[0042] The heating elements of the heating device can have substantially similar or identical sizes, geometries, shapes and / or thicknesses. This may allow heating the aerosol-forming substrate similarly or identically from the two opposing main faces, for example to generate a specific temperature gradient propagating through the substrate from the two opposing main faces of the aerosol-forming article towards the center thereof and towards each other. Alternatively, however, the heating elements may differ in one or more of size, geometry, shape and thickness.

[0043] The heating device may be configured to heat at least a part of the substrate of the aerosolforming article by conductive heating. Accordingly, the heating elements of the heating device may be configured to heat the substrate or article by conduction. Generally, conductive heating can be advantageous in terms of providing rapid and efficient heat transfer, optionally in a simple design, which can lead to quick vaporization of substrate material.

[0044] As used herein, heating by conduction may involve or include a direct transfer of heat or thermal energy from one or both heating elements to the aerosol-forming article or substrate. For example, at least a part of the heating device, and / or at least one of, preferably both heating elements may be configured or arranged to contact or directly contact the aerosol-forming article or substrate to heat the article or substrate.The heating elements of the heating device can include electrically conductive material and may be configured to be resistively heated. Accordingly, the heating elements may be resistive heating elements, also referred to as Joule-type heating elements.

[0045] As used herein, “resistive heating” means that the electrical resistance of the respective component is used to generate heat or thermal energy. Specifically, when applying electrical power to an electrically conductive element, at least a part of the electrical energy is converted to thermal energy or heat due to the electric losses in the material. This effect can be used to heatup at least a part of the heating elements of the heating device to increase their temperature and heat the substrate. Further, the resistively generated heat can at least partly be transferred to the aerosol-forming article or substrate based on conduction.

[0046] Alternatively, the two opposing heating elements may each include a susceptor configured to be inductively heated. For example, the heating device may comprise one or more heating coils configured to heat the heating elements based on or by induction.

[0047] For inductive heating, an alternating magnetic field may be generated by the one or more heating coils. The heating elements and / or susceptors may be at least partly arranged in the alternating filed, such that eddy currents can be induced in the susceptors of the heating elements, which are at least partly converted to heat in the susceptor material, thereby heating the heating elements.

[0048] Also, a combination of resistive and inductive heating elements may be used. For example, one heating element may be heated resistively and the other one may be heated by induction. Further optionally, the heating device may include one or more further heating elements, for example, configured to heat one or more lateral side faces of the aerosol-forming article. The heating elements heating the main faces and the one or more further heating elements heating the lateral side faces of the aerosol-forming article can employ different heating technologies. For instance, the heating elements may be resistive heating elements and the one or more further heating elements may be heated inductively, or vice versa.

[0049] The control circuitry can be configured to gradually, continuously or step-wise increase the temperature of the heating elements in the first phase of the usage session from the initial temperature to the first target temperature. Accordingly, the heating elements may be heated to one or more intermediate temperatures between the initial temperature and the first target temperature.

[0050] In an example, the first target temperature may be reached towards or at an end of the first phase of the usage session. Alternatively, the control circuitry can be configured to heat the heating elements to the first target temperature as fast as possible or at an intermediate time between the start and the end of the first phase, and to maintain the first the target temperature for the remaining time of the first phase. The latter can particularly allow reducing a waiting forthe user to start inhaling aerosol, which for example should occur towards or at the end of the first phase and / or at the start of the second phase.

[0051] For example, the control circuitry can be configured to increase the temperature of the heating elements and / or the substrate at the start of the first phase, for instance upon activation of the device by the user, about 100°C within about 0.05 to 1 seconds, or about 100°C within about 0.05 to 0.5 seconds, for example about 100°C within 0.075 to 0.25 seconds, preferably about 100°C within about 0.1 to 0.2 seconds. Optionally, the control circuitry may be configured to confirm or determine that the first target temperature has been reached, and to maintain the first target temperature for the remaining time of the first phase. Generally, the heating performed in the first phase can allow to quickly bring the substrate to an elevated temperature sufficient to release one or more ingredients thereof to generate aerosol, and for example prepare the substrate for aerosol consumption by the user, thereby reducing waiting time for the user to start inhalation, for example at the end of the first phase and / or beginning of the second phase.

[0052] The control circuitry can, for example, be configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature below the first target temperature. Therein, the control circuitry can be configured to gradually, continuously or step-wise decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to the second target temperature. Accordingly, the heating elements may be heated to one or more intermediate temperatures between the first target temperature and the second target temperature.

[0053] In an example, the second target temperature may be reached towards or at an end of the second phase of the usage session. Alternatively, the control circuitry can be configured to heat the heating elements to the second target temperature, for example decrease the temperature from the first to the second target temperature, at an intermediate time between the start and the end of the second phase, and to maintain the second the target temperature for the remaining time of the second phase.

[0054] The increase or boost of the temperature to the first target temperature in the first phase can, for example, lead to vaporization of at least a part, preferably the majority, of moisture or liquid constituents of the substrate. Such vaporization may also be accompanied by a cooling effect caused by the phase change of the liquid constituents from liquid to gaseous phase. This cooling can, for example, be compensated by heating the substrate to the first target temperature in the first phase which can be higher than the second target temperature in the second phase. Also, increasing the temperature of the heating elements in the first phase as fast as possible can allow reducing the waiting time for the user to start inhaling aerosol. After at least a part of the moisture or liquid constituents have been released from the substrate in the first phase, the temperature can be lowered to the second target temperature below the first target temperature.Overall, this can allow for a fast heating of the substrate, and can also lead to a homogenous taste during a single usage session or across several usage sessions.

[0055] The control circuitry can further be configured to increase the temperature of the heating elements in the third phase of the usage session from the second target temperature to a third target temperature above the second target temperature. Therein, the control circuitry can be configured to gradually, continuously or step-wise decrease the temperature of the heating elements in the third phase of the usage session from the second target temperature to the third target temperature. Accordingly, the heating elements may be heated to one or more intermediate temperatures between the second target temperature and the third target temperature.

[0056] The third target temperature may, for example, be reached towards or at an end of the third phase and / or of the usage session. With increasing duration of the usage session, an increasing amount or volume of aerosol has already been released from the substrate. Hence, increasing the temperature to the third target temperature can ensure that a sufficient amount or volume of aerosol can be released per unit time, thereby ensuring a substantially homogenous taste and experience over the duration of the usage session.

[0057] Alternatively, however, the control circuitry can be configured to heat the heating elements to the third target temperature, for example increase the temperature from the second to the third target temperature, at an intermediate time between the start and the end of the third phase, and to maintain the third the target temperature for the remaining time of the third phase.

[0058] In an example, the second target temperature of the second phase can be in a range from about 200°C to about 290°C, in particular from about 210°C to about 280°C, for example from about 220°C to about 270°C, preferably from about 220°C to about 250°C. Alternatively or additionally, the third target temperature of the third phase can be in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C. Alternatively or additionally, the first target temperature of the first phase can be in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C. These temperature ranges for the first, second and third phases, respectively, the first, second and third target temperatures, have been found by the inventors to lead to specific temperature gradients or heat profiles that can propagate through the substrate with advancing time from the start of the usage session, thereby resulting in a well-defined, preferably uniform heat distribution across the substrate over time.

[0059] The control circuitry can further be configured to maintain the temperature of the heating elements substantially constant during a fourth phase of the usage session. For example, the control circuitry can be configured to increase the temperature of the heating elements in the third phase of the usage session from the second target temperature to the third target temperatureabove the second target temperature, and substantially maintain the third target temperature during the fourth phase. Alternatively, however, the control circuitry may be configured to increase the temperature of the heating elements from the third target temperature to a fourth target temperature above the third target temperature. An optional increase to the fourth target temperature may be gradual, continuous or step-wise, and hence one or more intermediate temperatures may be reached between the third and fourth target temperature.

[0060] Generally, the fourth phase of the usage session may be optional. Accordingly, either the third phase can mark the end of the usage session or the optional fourth phase can mark the end of the usage session. However, optionally further phases may be used. When maintaining the heating elements at their temperature in the fourth phase, for example the third target temperature or an even higher fourth target temperature, a considerably high amount or volume of aerosol per unit time may be released from the substrate towards the end of the usage session. Hence, heating according to the optional fourth phase may result in an intense aerosol experience, which might be favorable in at least some scenarios or at least for some users.

[0061] In a non-limiting example, a duration of the first phase of the usage session may be between about 2 seconds and about 75 seconds, for example between about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 35 seconds. Such time periods for the first phase have been found optimal for quickly heating the substrate to the first target temperature, for example thereby releasing liquid constituents and moisture from the substrate. The first phase may further serve or allow to quickly bring the substrate to an elevated temperature sufficient to release aerosol from the substrate, such that the user can start inhaling the released aerosol in one or more user inhalations. For example, the user may typically start inhaling aerosol in the first phase, for example after reaching the first target temperature, towards or at the end of the first phase. Optionally, however, the user may also start inhaling aerosol in the second or even third phase.

[0062] In a further non-limiting example, a duration of the second phase of the usage session may be between about 2 seconds and about 100 seconds, for example between about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 30 seconds. Such time periods for the second phase have been found optimal allow the temperature gradient generated in the first phase to propagate through the substrate volume, thereby leading to a substantially uniform heat distribution across the substrate volume.

[0063] For instance, the control circuitry can be configured to signal to the user that the aerosolforming device is ready for being used upon reaching a predefined period of time from start of the usage session, for example from the time the aerosol-forming device was activated for aerosol consumption. Such predetermined period of time can refer to a heat-up phase for preparing the substrate and aerosol-forming device for aerosol consumption by the user in one or more userinhalations or puffs. For example, the predefined period of time for the heat-up phase can range from about 5 seconds, to about 35 seconds, for example from about 10 seconds to about 30 seconds, preferably from about 15 seconds to about 25 seconds, even more preferably about 20 seconds. Hence, depending on the durations of the first and second phases, the heat-up phase may be terminated in the first phase or the second phase.

[0064] Alternatively or additionally to a predefined fixed period of time for the heat-up phase, the control circuitry can be configured to signal to the user that the aerosol-forming device is ready for being used upon reaching a predetermined temperature, for example the first target temperature, the second target temperate, a temperature below the first target temperature, or a temperature between the first and second target temperatures.

[0065] Signaling to the user that the aerosol-forming device is ready for being used can include generating or triggering one or more user interface or user interface components of the aerosolforming device. For example, one or more of an acoustic, haptic and visual signal may be provided by the control circuitry upon termination of the heat-up phase based actuating or operating the one or more user interfaces or user interface components of the aerosol-forming device.

[0066] In a further non-limiting example, a duration of the third phase of the usage session may be between about 50 seconds and about 800 seconds, for example between about 150 seconds and about 600 seconds, preferably between about 200 seconds and about 450 seconds. As mentioned above, the user typically starts aerosol consumption in the first phase or second phase, and the third phase can constitute the major part of the time of a usage session where the user inhales aerosol in one or more user inhalations. The forementioned periods of time for the third phase have been found optimal in terms of user experience. Also, a substantially homogenous aerosol dose can be generated within these periods of time, which can further improve user experience and taste.

[0067] In an example, a duration of the third phase of the usage session can be longer than a duration of the first phase and longer than a duration of the second phase of the usage session. The third phase can constitute the phase where the user primarily experiences or inhales aerosol released from the heated substrate, whereas at least a part of the first phase and optionally also of the second phase can constitute a preparatory time period to prepare the substrate for the aerosol consumption or experience by the user. Accordingly, the preparatory time period may be shorter than the actual use time period where the user consumes aerosol. Hence, waiting times can be reduced and user experience can be improved.

[0068] In an example, the first phase can correspond to an initial boost in temperature to release moisture and liquid constituents from the substrate, and to pre-heat the substrate to a considerably high temperature sufficient to release one or more ingredients from the substrate, which can also be referred to herein as preparing the substrate for the subsequent aerosolexperience by the user. The descend or decrease in temperature of the second phase can allow for the temperature gradient generated during the first phase to propagate through the substrate and form a substantially or more uniform heat distribution across the substrate volume. Also, the decrease in temperature may allow to adjust an amount or volume of aerosol released per unit time from the substrate, which can be referred to as tuning of the released aerosol. In the third phase, the temperature can be gradually increased or ramped up to the third target temperature, which may allow to compensate for an increasing depletion of the substrate. Overall, an optimal user experience can be provided by this heating approach.

[0069] One or more of the duration of the first phase, the first target temperature, the duration of the second phase, the second target temperature, the duration of the third phase, the third target temperature, the duration of the fourth phase, and the fourth target temperature can be predefined or fixed, for example stored in corresponding data at the aerosol-forming device. Alternatively, any one or more of the duration of the first phase, the first target temperature, the duration of the second phase, the second target temperature, the duration of the third phase, the third target temperature, the duration of the fourth phase, and the fourth target temperature can be adjusted or modified by the control circuitry, for example based on or in accordance with an the initial temperature, the room or ambient temperature or other parameters.

[0070] The control circuitry can be configured to control the temperature of the heating elements based on at least one heating profile defining a course of the temperature of the heating elements over time during the usage session, preferably wherein the at least one heating profile is stored in a data storage of the aerosol-forming device. One or more heating profiles may be stored at the aerosol-forming device, for example in the form of temperature and time values or value pairs corresponding to one or more target temperatures that should be reached at the associated time after start of the usage session, for example after activation of the user or initiation of the usage session by the user. Accordingly, the at least one heating profile can be indicative of or define one or more target temperatures of the heating elements with respect to time during the usage session. The temperatures indicated or defined by the heating profile may be in the range from 125°C to 350°C. That is, a minimum temperature defined by the heating profile may be 125°C and / or a maximum temperature defined by the heating profile may be 350°C. Alternatively or additionally to temperature values, also one or more other parameters correlated with the temperature of the heating elements, such as for example electrical resistances or electrical power supplied to the heating elements, can be stored at the aerosol-forming device as heating profile.

[0071] Generally, the one or more heating profiles may be considered as instructions for the control circuitry at which time after start of the usage session which temperature should be reached by the heating elements. Accordingly, the control circuitry can be configured to control or operate theheating elements and / or power source, such that the heating elements are heated as defined in the one or more heating profiles.

[0072] The control circuitry can be configured to control the temperature of the heating elements based on a plurality of predetermined heating profiles, each defining one or more target temperatures of the heating elements with respect to time during the usage session. For example, different heating profiles may be stored at the aerosol-forming device for different types of substrate or aerosol-forming article. Alternatively or additionally, different heating profiles may correspond to different strengths or intensities of aerosol experiences, for example according to different habits or preferences of different users.

[0073] In an example, each heating profile may define a maximum duration for a usage session, wherein the control circuitry may be configured to stop or decrease the supply of power to the heating elements upon reaching the maximum duration of the usage session defined in one of the heating profiles currently applied for the usage session. Accordingly, the control circuitry may terminate the usage session after or upon reaching the maximum duration. This may ensure that the substrate cannot be overheated, for example in case it is already fully depleted.

[0074] When storing a plurality of heating profiles at the aerosol-forming device, the different heating profiles can differ from each other in one or more of a maximum duration of a usage session and an average temperature of the heating elements during the usage session. Different durations and average temperatures may allow to provide heating profiles tailored to specific aerosol-forming articles or substrates, and / or tailored to different user preferences. Optionally, different heating profiles can different in one or more of the phases defined therein, one or more target temperatures, one or more maximum temperatures, one or more average temperatures during one or more phases, and other characteristics.

[0075] In an example, the longer the maximum duration of a usage session associated with one of the heating profiles may be, the lower may be the average temperature of the heating elements during the respective usage session. Alternatively or additionally, the shorter the maximum duration of a usage session associated with one of the heating profiles may be, the higher may be the average temperature of the heating elements during the respective usage session.

[0076] In other words, a heating profile among the plurality of heating profiles that may be associated with a longer maximum duration of a usage session than another heating profile among the plurality of heating profiles, can be associated with a smaller average temperature of the heating elements than said other heating profile. Alternatively or additionally, a heating profile among the plurality of heating profiles that may be associated with a shorter maximum duration of a usage session than another heating profile among the plurality of heating profiles, can be associated with a higher average temperature of the heating elements than said other heating profile.Accordingly, a shorter usage session may be compensated by higher average temperature throughout the usage session, and vice versa. This may allow the release of similar or comparable amounts or volumes of aerosol from a given substrate across the plurality of heating profiles, but within different durations or time periods of the usage session. Accordingly, the same dose or amount of aerosol may be inhaled by the user, but within different periods of time according to the different heating profiles defining different maximum durations for the usage session. For example, this can allow providing a long aerosol experience with a long maximum duration of the usage session, but low average temperature. Alternatively or additionally, a medium or short aerosol experience with a medium or short maximum duration of the respective usage session, but with higher average temperatures compared to the long experience can be provided to the user.

[0077] As used herein, an average temperature during the usage session may refer to the average temperature from start or initiation of the usage session to end or termination of the usage session.

[0078] In an example, different heating profiles can differ from one another at least partly in terms of one or more of the duration of the first phase, an average temperature of the heating elements during the first phase, a maximum temperature of the heating elements during the first phase, the duration of the second phase, an average temperature of the heating elements during the second phase, a maximum temperature of the heating elements during the second phase, a minimum temperature of the heating elements during the second phase, the duration of the third phase of the usage session, an average temperature of the heating elements during the third phase, and a maximum temperature of the heating elements during the third phase.

[0079] The control circuitry can be configured to apply one of the plurality of heating profiles based on a user input at a user interface of the aerosol-forming device. For example, the control circuitry may be configured to select one of the plurality of heating profiles based on the user input. Therein, the user input may be indicative of the user’s preference in terms of length or intensity of the aerosol experience, which may optionally be selected by the user on the user interface. Accordingly, the user may select its preferred experience or type of experience, and the control circuitry may select the corresponding or associated heating profile. Alternatively or additionally, the user input may be indicative of a type of aerosol-forming article to be used in the current usage session. For example, the user may select one type among a plurality of types of aerosol-forming articles at the user interface, and the control circuitry may select the corresponding heating profile.

[0080] Selecting of a heating profile by the control circuitry can optionally include one or more of loading the selected heating profile, accessing data associated with the selected heating profile at a data storage of the aerosol-forming device or an external data storage, and retrieving theselected heating profile or data associated therewith from a smartphone or server communicatively couplable with the aerosol-forming device.

[0081] Alternatively or additionally, selecting of a heating profile by the control circuitry can optionally include enabling the selected heating profile at the aerosol-forming device, loading settings associated with the selected heating profile, and operating the heating device and / or heating elements in accordance or correspondence with the selected heating profile.

[0082] The control circuitry can optionally be configured to apply and / or select one of the plurality of heating profiles based on a type of the aerosol-forming article. Accordingly, the aerosol-forming device can be configured to automatically select a heating profile based on the type of aerosolforming article used. This can allow for a seamless adaption of the heating of the aerosol-forming device without requiring user selection or interaction, for example via user interface. Hence, user experience can be improved.

[0083] The aerosol-forming device can, for example, comprise at least one sensor for determining a type of the aerosol-forming article, wherein the control circuitry can be configured to apply and / or select one of the plurality of heating profiles based on determining the type of aerosol-forming article by means of the at least one sensor.

[0084] In an example, the at least one sensor may be configured to detect or determine one or more indicia on the aerosol-forming article to determine the type of the article. For instance, a code, barcode, QR code, visible code, invisible code, RFID tag or the like may be comprised by the aerosol-forming article. The at least one sensor may be configured to read the code, barcode, QR code, visible code, invisible code, RFID tag, and provide a corresponding signal to the control circuitry. The control circuitry, or optionally the sensor itself, can then determine the type of the aerosol-forming article, such that the control circuitry can select the heating profile associated with the respect type of aerosol-forming article.

[0085] The control circuitry can be configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature upon determining that the heating elements have reached the first target temperature. Alternatively or additionally, the control circuitry can be configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to the second target temperature upon determining that a duration of the first phase has expired, elapsed or has been reached, for example a predetermined, nominal or maximum duration of the first phase from the start of the first phase. Accordingly, a time-based control, a temperature-based control or both a time- and temperature-based control of the heating device and / or its heating elements can be applied or utilized by the control circuitry in the first and / or second phase of the usage session to operatively control the one or more of the heating device, the heating elements of the heating device and the power source.As used herein, controlling the heating elements or heating device can include controlling the power supply, power source or energy storage of the aerosol-forming device.

[0086] The control circuitry can further be configured to increase the temperature of the heating elements in the third phase of the usage session from a second target temperature to a third target temperature upon determining that the heating elements have reached the second target temperature. Alternatively or additionally, the control circuitry can be configured to increase the temperature of the heating elements in the third phase of the usage session from the second target temperature to the third target temperature upon determining that a duration of the second phase has expired, elapsed or has been reached, for example a predetermined, nominal or maximum duration of the second phase from the start of the second phase and / or the end of the first phase. Accordingly, time-based control, temperature-based control or both time- and temperature-based control of the heating device and / or its heating elements can be applied or utilized by the control circuitry in the second and / or third phase of the usage session to operatively control the one or more of the heating device, the heating elements of the heating device and the power source.

[0087] Optionally, upon determining that the duration of the third phase has expired, elapsed or has been reached, the control circuitry can be configured to at least reduce the power supply to the heating elements and / or heating device. For example, the control circuitry can be configured to deactivate, cut or completely stop the supply of power to the heating elements and / or heating device, thereby terminating the usage session.

[0088] The control circuitry can further be configured to maintain, in a fourth phase of the usage session, a third target temperature of the heating elements upon determining that the heating elements have reached the third target temperature. Optionally, however, the temperature of the heating elements may be increased from the third target temperature to a fourth target temperature. Alternatively or additionally, the control circuitry can be configured to maintain, in the fourth phase of the usage session, the third target temperature of the heating elements upon determining that a duration of the third phase has expired, elapsed or has been reached, for example a predetermined, nominal or maximum duration of the third phase from the start of the third phase and / or the end of the second phase. Accordingly, time-based control, temperaturebased control or both time- and temperature-based control of the heating device and / or its heating elements can be applied or utilized by the control circuitry in the third and / or fourth phase of the usage session to operatively control the one or more of the heating device, the heating elements of the heating device and the power source.

[0089] A duration of the fourth phase can be between about 25 seconds and about 300 seconds, for example between about 50 seconds and about 150 seconds.In an example, the control circuitry can be configured to maintain the temperature of the heating elements at the third target temperature reached in the third phase of the usage session for a duration of the fourth phase, for example a predetermined, nominal or maximum duration of the fourth phase of the usage session, upon determining that a duration, for example predetermined, nominal or maximum duration, of the third phase has elapsed expired or has been reached. Accordingly, time-based control may be applied by the control circuitry in the fourth phase to operatively control the one or more of the heating device, the heating elements of the heating device and the power source. Alternatively or additionally, temperature-based control may be applied to terminate the fourth phase, for example upon reaching a fourth target temperature.

[0090] Optionally, upon determining that the duration of the third or fourth phase has expired, elapsed or has been reached, or the third or fourth target temperatures have been reached, the control circuitry can be configured to at least reduce the power supply to the heating elements and / or heating device. For example, the control circuitry can be configured to deactivate, cut or completely stop the supply of power to the heating elements and / or heating device, thereby terminating the usage session.

[0091] The control circuitry can further be configured to control the supply of power to both heating elements, such that the temperatures of both heating elements are substantially equal. Accordingly, the control circuitry can be configured to control the power source or energy storage, such that the temperatures of both heating elements are substantially equal. This may include providing similar or identical power levels, voltages and / or currents to the heating elements. This may ensure a similar or identical heating of the aerosol-forming substrate from the two opposing main faces of the aerosol-forming article. Hence, the substrate may be rapidly and homogenously heated from two sides.

[0092] The control circuitry can be configured to control the temperature of the heating elements based on controlling one or more of an electrical voltage supplied to the heating elements or an induction or heating coil, and an electrical current supplied to the heating elements or an induction coil. Accordingly, depending on the type of heating device or heating technology applied, the temperature of the heating elements may be controlled differently. In case of resistive heating, one or more of the electrical power level, the voltage and current supplied to the heating elements may be controlled or regulated by the control circuitry. In case of inductive heating one or more of the one or more of the electrical power level, the voltage and current supplied to one or more induction or heating coils can be controlled or regulated by the control circuitry.

[0093] The control circuitry can further be configured to determine the temperature of the heating elements based on determining an electrical resistance of the heating elements. Optionally, the control circuitry can be configured to regulate or control the temperature of the heating elements based on determining or measuring the electrical resistance of the heating elements. Generally,utilizing the electrical resistance to determine the temperature may allow for a precise and reliable determination of the temperature without requiring a dedicated temperature sensor. Optionally, however, a temperature sensor may be used instead of or in addition to measuring the electrical resistance.

[0094] It should be noted that any reference to a “resistance” of the heating elements in the following, relates to the electrical resistance, unless explicitly stated otherwise.

[0095] Also, any reference to or disclosure related to a determination or measurement of a temperature of heating elements can include a determination or measurement of the electrical resistance of the heating elements, and vice versa. The same applies to any heating device described herein.

[0096] In an example, the control circuitry may be configured to monitor or determine the electrical resistance of the heating elements during the usage session. Therein monitoring the resistance may include determining the electrical resistance with a predetermined repetition or sampling frequency, for example in the Hertz to Kilohertz or even Megahertz range. Further optionally, the control circuitry can be configured to adjust the temperature of the heating elements as defined in one of the heating profiles based on determining the electrical resistance of the heating elements.

[0097] The electrical resistance of a material depends on the temperature of the material, which particularly applies to electrically conductive materials that show an increase in the electrical resistance with increasing temperature. Therefore, the temperature of one of or both the heating elements of the heating device can be precisely and reliably determined based on determining or measuring the electrical resistance thereof. Similarly, also changes in the temperature of the heating device and / or the heating elements can be reliably and precisely determined based on determining changes in the electrical resistance of the respective component.

[0098] For example, the electrical resistance of heating elements can be measured or determined by the control circuitry by or based on one or more of determining a voltage across or supplied to the heating elements, determining a current across or supplied to the heating elements, and determining a voltage drop across a shunt resistor.

[0099] For example, the heating elements may be connected in series, and the control circuitry may be configured to regulate or control the temperature of one or both heating elements based on determining the total electrical resistance of both heating elements. Determining the total resistance rather than individual resistance values for each heating element may reduce complexity of the control circuitry.

[0100] The control circuitry can further be configured to regulate or control the temperature of the heating elements based on determining an electrical resistance of the heating elements, forexample total resistance of both heating elements, and based on one or more predetermined calibration values associating the electrical resistance with a temperature of the heating elements.

[0101] Optionally, one or more conversion or calibration values for computing one or more temperature values based on determined one or more resistance values of the heating elements may be stored in a data storage or memory of the aerosol-forming device, for example in the form of a look-up table, correlation table or matrix. The control circuitry may access or process the one or more conversion or calibration values to compute temperature values based on determined resistance values. Alternatively or additionally, one or more conversion or calibration values for computing one or more resistance values based on determined one or more temperature values may be stored in a data storage or memory of the aerosol-forming device, for example in the form of a look-up table, conversion table or matrix. The control circuitry may access or process the one or more conversion or calibration values to compute resistance values based on determined temperature values.

[0102] The control circuitry may be configured to initiate the usage session and / or increase the temperature of the heating elements from the initial temperature to the first target temperature in response to or upon determining one or more of:

[0103] a sensor signal of at least one sensor of the aerosol-forming device;

[0104] insertion of an aerosol-forming article at least partly into the aerosol-forming device; coupling of an aerosol-forming article to the aerosol-forming device;

[0105] mechanical decoupling of the aerosol-forming device from a companion device; and a control signal from one or more user interfaces triggered by a user of the aerosol-forming device. Such events or actions may reliably indicate the user’s intention to activate or use the aerosol-forming device for aerosol consumption, and hence may constitute reliable triggers for the control circuitry to activate the heating device and start the usage session, respectively the first phase thereof.

[0106] In an example, one or more sensors configured to provide a sensor signal indicative of a potential imminent use of the aerosol-forming device for aerosol-consumption may be used to trigger initiation of the usage session and heating of the heating elements. Non-limiting examples of sensors that could be used for this purpose include, accelerometers, motion detection sensors, inertial sensors, gyroscopes, presence detection sensors, proximity detection sensors, near field sensors, touch sensors (temperature based or other), capacitive sensors and others.

[0107] The control circuitry can be configured to continuously heat the aerosol-forming article or substrate during the usage session. Continuous heating may mean that the temperature of the heating elements is kept at a value above room or ambient temperature throughout the usage session. Also, continuous heating may include heating the heating device or heating elements with pulses of voltage and / or current having a comparatively high repetition or pulse frequency,for example a pulse repetition in the range of deciseconds, milliseconds, microseconds or even higher. For example, continuous heating may include heating based on pulse width modulation (PWM), on-off or bang-bang type heating, or other heating where the electric power delivery to the heating elements may not be continuous.

[0108] The aerosol-forming device may further comprise an upstream airflow path arranged upstream of the heating device, the heating chamber and / or the heating volume, wherein the upstream airflow path is in fluid communication with an external environment of the aerosolforming device, such that air is drawable by a user in a user inhalation from the external environment through the upstream airflow path towards the heating volume, heating chamber and / or heating device. The aerosol-forming device may further comprise an upstream heating device arranged in thermal contact with the upstream airflow path and configured to convectively heat air in the upstream airflow path to heat at least heat a part of a substrate of the aerosolforming article.

[0109] Generally, the upstream heating device may allow preheating the incoming air or airflow caused by the user inhalation, such that air at elevated temperature can reach the aerosol-forming article or substrate when placed in the heating volume. Hence, the substrate can be heated more rapidly to the respective target temperatures in the respective phases of the usage session. Also the airflow may flow through the aerosol-forming article, thereby providing supplementary heating from the inside of the article to the heating from the two opposing main faces of the aerosolforming article provided by the heating elements of the heating device.

[0110] The upstream airflow path may refer to an airflow path where the air comes from before reaching the heating chamber, heating device and / or heating volume. Further, an airflow through the heating chamber, heating volume and / or aerosol-forming article that is caused by a user inhalation may be substantially directed along a longitudinal axis of the aerosol-forming device and / or article.

[0111] The upstream airflow path can be in fluid communication with the external environment or a surrounding of the aerosol-forming device. This may mean that the upstream airflow path is fluidly coupled or connected to the surrounding or external environment of the device. The airflow through the upstream airflow path may also be referred to herein as upstream airflow. Unless explicitly stated otherwise in the following, a reference to an airflow path or the airflow path, refers to the upstream airflow path.

[0112] For example, the upstream airflow path may be fluidly coupled to the external environment via one or more air inlets, also referred to herein as main air inlets or device inlets. Optionally, the upstream airflow path and the one or more air inlets may be fluidly interconnected by one or more airflow path structures or elements configured to guide or convey the air from the one or more air inlets towards or to the upstream airflow path. The one or more airflow path structures or elementsmay, for example, be defined by one or more walls or components arranged in a housing or device body of the aerosol-forming device.

[0113] The upstream heating device being arranged in thermal contact with the upstream airflow path may mean or include that at least a part of the upstream heating device is thermally coupled to the upstream airflow path, such that heat or thermal energy can be exchanged between the upstream heating device and the upstream airflow path or the airflowthrough the upstream airflow path. For example, at least a part of the upstream heating device may be arranged in or protrude into the upstream airflow path, such that air can pass along at least a part of the surface of the upstream heating device. Alternatively or additionally, the upstream heating device may exchange heat or thermal energy with the air in the upstream airflow path via at least one thermally conductive element.

[0114] The upstream heating device may include a resistive heating device or resistive heating element configured to heat air in the upstream airflow path to at least heat a part of the substrate of the aerosol-forming article by convective heating.

[0115] As used herein, convective heating can relate to heat transfer from a heating device, in particular the upstream heating device, that involves the movement of hot air or gas to heat the aerosol-forming substrate or article. For instance, the upstream heating device can be configured to be resistively heated and to heat the air around, for example flowing past, the upstream heating device or at least a part thereof. The heated air may then be conveyed or guided through the upstream airflow path towards the heating chamber, where the aerosol-forming article or substrate may be situated. Hence, the aerosol-forming substrate or article can be heated by the flow of hot or heated air generated by the upstream heating device. The airflow for efficiently heating the aerosol-forming article or substrate may be provided or driven by the actual user inhalation or puff.

[0116] The upstream heating device may be configured to perform a puff-on-demand heating operation, also referred to as response-to-draw operation. Alternatively or additionally, the control circuitry may be configured to control the upstream heating device to perform a puff-on-demand heating operation. For example, the control circuitry can be configured to regulate or control a supply of electrical power to the upstream heating device in accordance or correspondence with the occurrence of one or more user inhalations taken or performed by the user. In particular more power or a higher power level, for example higher voltage and / or current, may be supplied to the upstream heating device during a puff or user inhalation compared to times when no user inhalation occurs. Optionally, the upstream heating device may only be supplied with electrical power during a user inhalation, and / or no electrical power may be supplied at other times. Generally, puff-on-demand heating of the upstream heating device can reduce energy consumption and allow operation of the aerosol-forming device in an energy efficient manner.In the context of the present disclosure, a "puff-on-demand" heating operation may refer to a method of controlling the upstream heating device based on or in accordance with a user inhalation or puff being performed or occurring. For instance, upstream heating device may be activated only during at least a part of the user inhalation or only powered at a power level sufficient to generate aerosol during at least a part of the user inhalation, rather than being continuously heated throughout an entire usage session. Puff-on-demand heating can be designed to optimize energy efficiency and, for example, enhance user experience by providing aerosol only when needed, thereby reducing unnecessary heating and potential degradation of the aerosol-forming substrate. A puff-on-demand heating operation of the aerosol-forming device, as used herein, may include or refer to operation of the aerosol-forming device, respectively, the upstream heating device, according to a puff-on-demand heating scheme. Further, it is noted that the terms puff and user inhalation are synonymously and interchangeably used herein.

[0117] The aerosol-forming device may, in an example, comprise a puff sensor configured to detect a user inhalation at the aerosol-forming device. Alternatively or additionally, the control circuitry may be configured to detect a user inhalation, for example start, occurrence or termination thereof, based on a puff sensor. Exemplary puff sensors can include pressure sensors, acoustic sensors, flow sensors, capacitive sensors and accelerometer-based sensors.

[0118] In yet a further example, the control circuitry may be configured to determine a user inhalation at the aerosol-forming device based on determining a change in a temperature of at least one of the heating device and the upstream heating device caused by a change in the airflow through the upstream airflow path resulting from the user inhalation.

[0119] Accordingly, the aerosol-forming device, respectively, the control circuitry thereof can detect or determine a temperature change caused by the change in the airflow through the upstream airflow path that is induced by or results from the user inhalation or puff taken by the user. For example, if the user inhales, air or fresh air may be drawn from the external environment into the upstream airflow path, such that an airflow, also referred to as upstream airflow, is generated in the upstream airflow path. The fresh air drawn from the external environment may substantially have room or ambient temperature, and hence can depart a cooling effect onto the heating device and / or upstream heating device. Therefore, the change in temperature, which in this example is a decrease in temperature, can be indicative of the user inhalation, of a start of the user inhalation and / or of occurrence of the user inhalation at the aerosol-forming device. Hence, by determining the change in temperature of one of or both the heating device and upstream heating device, the control circuitry can gain information about or can be enabled to detect the user inhalation at the aerosol-forming device. Moreover, if the user stops inhaling, the airflow through the upstream airflow path stops or is at least reduced, which can cause a further change in the temperature of one of or both the heating device and the upstream heating device. Specifically, termination orstop of the user inhalation can lead to or cause an increase in temperature of one of or both the heating device and the upstream heating device, which can be determined or detected by the control circuitry. Thereby, the control circuitry can be enabled to detect or determine termination or stop of the user inhalation at the aerosol-forming device.

[0120] Hence, based on determining one or more changes in the temperature of one of or both the heating device and the upstream heating device, the control circuitry can be enabled or configured to detect one or more user inhalations. In turn, this can allow for an operational control of one or more of the heating device, the upstream heating device and the power source or energy source in accordance or correspondence with the one or more detected changes in the temperature of one or both the heating device and the upstream heating device.

[0121] The control circuitry may be configured to determine or detect one or more of the user inhalation, occurrence of the user inhalation, a duration of the user inhalation, an onset of the user inhalation, and a start of the user inhalation at the aerosol-generating device based on determining or detecting a change or decrease in the temperature of at least one of the heating device and the upstream heating device.

[0122] Alternatively or additionally, a change in temperature, in particular an increase in temperature, of one or both the heating device and the upstream heating device may occur when the user stops inhaling, respectively when the user inhalation is terminated or ended. Accordingly, the control circuitry can be configured to determine or detect one or more of the user inhalation, termination of the user inhalation, an end of the user inhalation and a duration of the user inhalation based on determining or detecting a change or an increase in the temperature of one of or both the heating device and the upstream heating device.

[0123] Accordingly, the control circuitry can be configured to detect or determine a user inhalation at the aerosol-forming device based on one of or both detecting a decrease in the temperature and an increase in the temperature of one of or both the heating device and the upstream heating device. Hence, the control circuitry can provide the functionality of a puff sensor based on determining changes in the temperature of the heating device and / or the upstream heating device.

[0124] At least in some configurations or designs, the upstream heating device may have a lower thermal mass compared to the heating device. This can be particularly true in case the upstream heating device is designed or configured as convective heater that can heat the aerosol-forming article or substrate by convective heating. Due to the lower thermal mass, the temperature of the upstream heating device may adapt more quickly to the temperature of the air surrounding or flowing past the upstream heating device, when compared to the heating device. Hence, a response time for detecting an actual change in the temperature of the upstream heating device, and hence a response time for detecting the user inhalation, can be reduced by using the upstream heating device compared to relying on the heating device, at least in certain designsand configurations of the two heating devices. Hence, utilizing the upstream heating device as temperature sensor and / or as puff detection sensor, can allow for a fast and precise control of the aerosol-forming device.

[0125] The control circuitry can be configured to control a supply of power to the upstream heating device based on detecting a user inhalation at the aerosol-forming device. For instance, the control circuitry can be configured to supply electrical power to the upstream heating device in response to or upon detecting a user inhalation at the aerosol-forming device. Alternatively or additionally, the control circuitry may be configured to reduce or stop the supply of electrical power to the upstream heating device at times where no user inhalation occurs. Hence, the upstream heating device can be operated in correspondence with the occurrence of user inhalations, thereby allowing for an energy efficient operation of the aerosol-forming device.

[0126] The control circuitry can further be configured to, in response to detecting a user inhalation at the aerosol-forming device, increase a temperature of the upstream heating device to a target temperature for the upstream heating device. Optionally, also the temperature of the heating elements may be increased in response to detecting the user inhalation. In particular, the control circuitry can be configured to immediately increase the temperature of the upstream heating device, and optionally heating device, upon detecting a user inhalation. This may ensure that the substrate can be quickly heated when the user inhales.

[0127] The control circuitry can be configured to increase the temperature of the heating elements in response to detecting a user inhalation at the aerosol-forming device to the target temperature of the upstream heating device. Alternatively or additionally, the control circuitry can be configured to increase or boost the temperature of the heating elements during a user inhalation at the aerosol-forming device.

[0128] For example, when increasing the temperature of the upstream heating device and / or when powering the upstream heating device upon detecting a user inhalation, the temperature of the upstream heating device and / or substrate can increase about 100°C within about 0.05 to 1 seconds, for example about 100°C within about 0.05 to 0.5 seconds, or for example about 100°C within 0.075 to 0.25 seconds, preferably about 100°C within about 0.1 to 0.2 seconds. In an example, the temperature of the upstream heating device may increase from ambient temperature to about 300°C within about 100 ms and / or to about 500°C within about 700 ms.

[0129] A target temperature of the upstream heating device, to which it may be heated during occurrence of a user inhalation, may be in a range from about 270°C to about 500°C, for example from about 270°C to about 450°C, or for example from about 270°C to about 320°C, in particular from about 280°C to about 310°C, preferably about 300°C. These temperature ranges have been found to lead to rapid heating of the substrate at minimum risk for overheating.The control circuitry may further be configured to decrease or stop a supply of electrical power to the upstream heating device in response to detecting that a user inhalation at the aerosol-forming device has ended. This may allow reducing the overall energy consumption.

[0130] The control circuitry can further be configured to control the temperature of the upstream heating device based on at least one predetermined heating profile defining at least one target temperature of the upstream heating device, to which the upstream heating device is to be heated during a user inhalation. For example, a single target temperature that shall be applied or reached in each user inhalation may be defined. Alternatively, different target temperatures for different user inhalations during a single usage session may be defined. For instance, the target temperature may gradually or step-wise increase or decrease from a start of the usage session towards an end thereof.

[0131] In an exemplary implementation, the at least one heating profile of the upstream heating device can define one or more user inhalations of a usage session, during which one or more user inhalations a power supplied to the upstream heating device can be smaller than a power supplied during other user inhalations of the usage session. Optionally, the power supplied during said user inhalations may be zero, which may mean that upstream heating device can be deactivated or not heated during said user inhalations.

[0132] The control circuitry can be configured to determine a number of user inhalations occurring during the usage session, for example based on counting the number of user inhalations or puffs from start of the usage session, and to control the power supplied to the upstream heating device for each user inhalation as defined in the heating profile. Hence, the upstream heating device can be controlled based on a puff count or number.

[0133] For example, the one or more user inhalations, during which the power supplied to the upstream heating device can be smaller than the power supplied during other user inhalations of the usage session, may correspond to one or more user inhalations during one of the first, phase, the second phase, the third phase, the fourth phase or any other phase. For example, the one or more user inhalations, during which the power supplied to the upstream heating device can be smaller than the power supplied during other user inhalations of the usage session, may correspond to the first one or more user inhalations during a usage session or to the last one or more user inhalations of a usage sessions. Reducing the power supplied to the upstream heating device or deactivating the upstream heating device during predefined user inhalations may allow to tune the generation of aerosol in the substrate, thereby improving user experience and taste.

[0134] Optionally, the control circuitry may be configured to, respectively the heating profile of the upstream heating device may define one or more user inhalations at a time between start and end of the usage session, and / or one or more user inhalations at the end of the usage session, where the power to the upstream heating should be reduced or cut completely.The aerosol-forming device may store a plurality of heating profiles for the upstream heating device, and the control circuitry may be configured to select one of the heating profiles, for example based on a user input or based on determining a type of the aerosol-forming article, as explained above with respect to selection of a heating profile for the heating device by the control circuitry. Accordingly any disclosure herein about the selection of a heating profile equally applies to both selection of a heating profile for the upstream heating device and selection of a heating profile for the heating device.

[0135] For example, different heating profiles for the upstream heating device may differ in one or more target temperatures for one or more user inhalations during a usage session, a duration of the usage session, and a number of user inhalations, at which the control circuitry is supposed to reduce or cut the power supplied to the upstream heating device.

[0136] The control circuitry can be configured to control the temperature of the heating elements based on at least one predetermined heating profile associated with the heating device, and to control the temperature of the upstream heating device based on at least one predetermined heating profile associated with the upstream heating device. Therein, the at least one predetermined heating profile associated with the heating device can differ from the at least one heating profile associated with the upstream heating device. In particular, the heating profile of the heating device may instruct the control circuitry to perform continuous heating throughout the usage session with the heating device, and the heating profile for the upstream heating device may instruct the control circuitry to perform a puff-on-demand heating during the usage session with the upstream heating device. Accordingly, each heating device may be independently and separately controlled by the control circuitry, thereby allowing to fine-tune and optimize the heating of the substrate.

[0137] As noted above, the aerosol-forming article can have a substantially rectangular parallelepiped and / or cuboid shape defining two opposing main faces and two opposing side faces or lateral faces, the aerosol-forming article including an aerosol-forming substrate arranged between the two opposing main faces, preferably wherein the aerosol-forming article comprises an air inlet and an air outlet or aerosol-outlet located opposite of each other on the smallest faces of the rectangular parallelepiped shaped aerosol-forming article. The air inlet of the aerosolforming article may also be referred to herein as upstream air inlet of the article, and the air or aerosol outlet of the article may also be referred to herein as downstream air or aerosol outlet of the aerosol-forming article.

[0138] The aerosol-forming device may have a longitudinal axis, a transverse axis, and a normal axis, each being transverse, in particular orthogonal, to each other. The longitudinal direction of the aerosol-forming device may be parallel to the longitudinal axis and / or may extend from a proximal end or portion towards a distal end or portion of the aerosol-forming device. Therein, theproximal end or portion may be associated with a downstream element of the device, also referred to as mouthpiece portion, or a mouthpiece that can be contacted by a user’s mouth during aerosol generation or consumption. The longitudinal axis may be coaxial to or define a center axis and / or an insertion axis of the aerosol-forming device for inserting the aerosol-forming article into the device. Unless otherwise stated, a reference to a longitudinal axis may mean the center axis or longitudinal center axis. A transverse direction of the aerosol-forming device may be parallel to the transverse axis, and a normal direction of the aerosol-forming device may be parallel to the normal axis. When the transverse axis and the longitudinal axis of the aerosol-forming device are both arranged, oriented or aligned in a horizontal plane, the normal axis of the aerosol-forming device defines a vertical axis of the aerosol-forming device. Therefore, the normal axis or direction may also be referred to herein as vertical axis or direction of the aerosol-forming device.

[0139] The heating chamber, as used herein, may generally refer to a space or volume within the aerosol-forming device that is configured to at least partly receive or accommodate the aerosolforming article in order to heat it during a usage session. The heating chamber may also be referred to herein as or may comprise a heating volume of the aerosol-forming device. At least a part of the heating device may define at least a part of the heating chamber. For example, the heating device may comprise at least two opposing and spaced-apart heating elements which define the heating chamber and / or heating volume, for example as the space between the opposing heating elements.

[0140] The longitudinal axis of the aerosol-forming device may define or be coaxial to a longitudinal axis of the heating chamber and / or heating volume. The transverse axis of the aerosol-forming device may define or be coaxial to a transverse axis of the heating chamber and / or heating volume. The normal axis of the aerosol-forming device may define or be coaxial to a normal axis of the heating chamber and / or heating volume.

[0141] Accordingly, at least when the aerosol-forming article is at least partly inserted in the heating chamber and / or heating volume, the longitudinal axis of the aerosol-forming device may define or be coaxial to a longitudinal axis of the aerosol-forming article. The transverse axis of the aerosolforming device may define or be coaxial to a transverse axis of the aerosol-forming article. The normal axis of the aerosol-forming device may define or be coaxial to a normal axis of the aerosolforming article.

[0142] Further, the longitudinal direction may define and / or may be parallel to an insertion direction, along which the aerosol-forming article may be inserted into the heating chamber and / or heating volume. Accordingly, the longitudinal axis may define and / or may be parallel to the insertion axis.

[0143] An extension, length or size of the aerosol-forming device, the heating chamber, the heating volume and / or the aerosol-forming article may be longer in longitudinal direction than in directions transverse, for example orthogonal, thereto. Specifically, the aerosol-forming device, the heatingchamber, the heating volume and / or the aerosol-forming article, respectively, may have a length measured along the longitudinal direction or axis, a width measured along the transverse direction or axis, and a thickness or height measured along the normal axis or direction of the aerosolforming device, the heating chamber, heating volume and / or the aerosol-forming article, respectively. The transverse axis may also be referred to herein as width axis, and the transverse direction may also be referred to herein as width direction. Further, the normal axis may also be referred to herein as height or thickness axis, and the normal direction may also be referred to herein as height or thickness direction of the aerosol-forming device, the heating chamber, heating volume and / or the aerosol-forming article, respectively.

[0144] The aerosol-forming article may have a substantially rectangular parallelepiped shape. Alternatively or additionally, the aerosol-forming article may be plate-like or cuboid formed. The aerosol-forming article may comprise two opposing main surfaces, which may be substantially flat or planar. When the aerosol-forming article is inserted into the aerosol-forming device, a surface normal vector of the two opposing main surfaces may be parallel to the normal axis of the aerosol-forming device. Further, the aerosol-forming article may comprise two end faces or surfaces, in particular substantially flat or planar end faces, which are arranged opposite to each other and are spaced apart from each other in longitudinal direction of the aerosol-forming device, when the aerosol-forming article is inserted into the aerosol-forming device. The two end faces or surfaces may form the smallest surfaces of the aerosol-forming article, and are thus also referred to as smallest faces or surfaces of the aerosol-forming article. Moreover, the aerosol-forming article may comprise two lateral faces or side faces, in particular substantially flat or planar lateral faces or surfaces, which are arranged opposite to each other and are spaced apart from each other in transverse direction of the aerosol-forming device, when the aerosol-forming article is inserted into the aerosol-forming device. Accordingly, each of the lateral faces or side faces of the aerosol-forming article may have a surface normal vector substantially parallel to the transverse axis of the aerosol-forming device, when the aerosol-forming article is inserted into the aerosol-forming device.

[0145] The heating chamber and / or heating volume may have a substantially rectangular parallelepiped shape and / or may be configured to receive a substantially rectangular parallelepiped shaped aerosol-forming article. The heating chamber and / or heating volume may comprise two opposing main surfaces, which may be substantially flat or planar. Optionally, each of the two main surfaces may be defined or provided by heating elements of the heating device of the aerosol-forming device, for example substantially flat or planar heating elements. A surface normal vector of the two opposing main surfaces may be parallel to the normal axis of the aerosolforming device. Further, the heating chamber and / or heating volume may comprise two end faces or surfaces, in particular substantially flat or planar end faces, which are arranged opposite toeach other and are spaced apart from each other in longitudinal direction of the aerosol-forming device. The two end faces or surfaces may form the smallest surfaces of the heating chamber and / or heating volume. It is noted that these surfaces or faces may refer to an open volume provided by the heating chamber and / or heating volume. For example, at least one of the end faces or surfaces may be an open end, for example defining an insertion opening for the aerosolforming article. Moreover, the heating chamber and / or heating volume may comprise two lateral faces, in particular substantially flat or planar lateral faces or surfaces, which are arranged opposite to each other and are spaced apart from each other in transverse direction of the aerosol-forming device. Accordingly, each of the lateral faces of the heating chamber and / or heating volume may have a surface normal vector substantially parallel to the transverse axis of the aerosol-forming device.

[0146] As mentioned above, the aerosol-forming article may have an air inlet, for example arranged at a distal end of the article, and air or aerosol outlet, for example arranged at a proximal end of the article. The air inlet and aerosol-outlet may be located opposite of each other on the smallest faces or surfaces of the substantially rectangular parallelepiped shaped aerosol-forming article. The air inlet and the air outlet and may be spaced apart from each other along the longitudinal direction.

[0147] The aerosol-forming article may have a length, for example as measured along the insertion axis and / or along the longitudinal direction or axis of the aerosol-forming device or article, in a range between 20 mm and 40 mm, preferably between 25 mm and 35 mm, more preferably about 30 mm. The aerosol-forming article may have a width, for example as measured along the transverse direction of the aerosol-forming device or article, in a range between 7 mm and 15 mm, preferably between 9 mm and 13 mm, more preferably about 11 mm. The aerosol-forming article may have a thickness or height, for example as measured along the normal direction of the aerosol-forming device or article, of between 1 mm and 10 mm, for example between 2 mm and 5 mm, preferably between 2.5 mm and 4 mm, more preferably about 3.1 mm. Therein, the length may refer to a minimum, mean or maximum length, the width may refer to a minimum, mean or maximum width and the thickness may refer to a minimum, mean or maximum thickness, respectively, height of the aerosol-forming article.

[0148] The aerosol-forming substrate may have a substantially planar, cuboid, or rectangular parallelepiped shape and may be located between a top and bottom cover sheet inside the aerosol-forming article, wherein the substrate may have a length, for example as measured along the insertion axis and / or along the longitudinal direction of the aerosol-forming device or article, of about 8 mm to 15 mm, preferably about 12 mm. The substrate may further have a width, for example as measured perpendicularly to the insertion direction and / or along the transverse direction of the aerosol-forming device or article, of about 6 mm to 13 mm, preferably about 8mm. Therein, the length may refer to a minimum, mean or maximum length, and the width may refer to a minimum, mean or maximum width of the aerosol-forming substrate.

[0149] The substrate may particularly be or include a solid substrate material, although it is not limited thereto. Alternatively or additionally, the aerosol-forming substrate may be a solid substrate. For example, the substrate may include tobacco-based material, herbs, Cannabisbased material, or other solid substrate material. Optionally, however, also moisture, other liquid constituents and / or one or more active ingredients may be comprised in the substrate. It is noted, though, that the present disclosure is not limited to solid substrates or substrates containing solid material, but can be applied to vaporizers or vaping devices that generate aerosol by vaporizing liquid substrate material.

[0150] A weight or mass of the aerosol-forming substrate weight may be in a range between about 100 mg and about 260 mg, more preferably between about 130 mg and about 240 mg, even more preferably about 150 mg and about 210 mg, most preferably about 180 mg.

[0151] The aerosol-forming substrate may comprise a plurality of granules or beads of substrate material, wherein a bulk density of the aerosol-forming substrate may be in a range of about 0.4 g / cm3to about 0.8 g / cm3, preferably about 0.6 g / cm3. Therein, the bulk density may be defined as the mass of the particles divided by the total volume they occupy. This volume can include the space between granules or beads as well as the space within the particles themselves.

[0152] The aerosol-forming substrate may comprise a plurality of granules or beads of substrate material, wherein a density of single granules or beads of the substrate may be at least 0.75 grams per cubic centimetre, more preferably at least 0.8 grams per cubic centimetre, more preferably at least 0.9 grams per cubic centimetre, more preferably at least 1 gram per cubic centimetre, more preferably at least 1.1 grams per cubic centimetre, more preferably at least 1.2 grams per cubic centimetre.

[0153] The aerosol-forming substrate may comprise a plurality of granules or beads of substrate material, wherein a density of single granules or beads of the substrate of the may be less than or equal to 2 grams per cubic centimetre, more preferably less than or equal to 1.95 grams per cubic centimetre, more preferably less than or equal to 1.9 grams per cubic centimetre, more preferably less than or equal to1.85 grams per cubic centimetre, more preferably less than or equal to 1.8 grams per cubic centimetre.

[0154] The aerosol-forming article can comprise a cavity, also referred to as substrate chamber, and a frame positioned between the two opposing main faces of the aerosol-forming article. The frame may at least partly define the cavity. The cavity may be configured and / or arranged to accommodate or receive the aerosol-forming substrate. In particular, the cavity may be at least partially, preferably entirely filled with aerosol-forming substrate.The cavity may have a length, for example measured along the longitudinal axis of the aerosol-forming article or device, of at least 10 millimetres, or at least 12 millimetres. The cavity may have a length of less than or equal to 20 millimetres, or less than or equal to 15 millimetres. For example, the cavity may have a length of between 10 millimetres and 20 millimetres, or between 12 millimetres and 15 millimetres.

[0155] The cavity may have a width, for example measured along the transverse axis or width direction of the aerosol-forming device, of at least 5 millimetres, or at least 6 millimetres. The cavity may have a width of less than or equal to 10 millimetres, or less than or equal to 8 millimetres. For example, the cavity may have a width of between 5 millimetres and 10 millimetres, or between 6 millimetres and 8 millimetres.

[0156] The cavity may have a depth or thickness, for example measured along the normal direction of the aerosol-forming device, of at least 2 millimetres, or at least 3 millimetres. The cavity may have a depth of less than or equal to 5 millimetres, or less than or equal to 4 millimetres. For example, the cavity may have a depth of between 2 millimetres and 5 millimetres, or between 3 millimetres and 4 millimetres, for example between 2.5 millimetres and 4 mm millimetres.

[0157] The cavity may have a volume of at least 200 cubic millimetres, or at least 250 cubic millimetres. The cavity may have a volume of less than or equal to 400 cubic millimetres, or less than or equal to 350 cubic millimetres. For example, the cavity may have a volume of between 200 cubic millimetres and 400 cubic millimetres, or between 250 cubic millimetres and 350 cubic millimetres. The cavity may substantially be completely filled with substrate material, for example a plurality of beads or granules. Accordingly, the dimensions of the cavity may correspond to dimensions, volumes and sizes of the aerosol-forming substrate may substantially correspond to or define the dimensions, volumes and sizes of the aerosol-forming substrate.

[0158] The aerosol-forming substrate may have a length, for example measured along the longitudinal axis of the aerosol-forming article or device, of at least 10 millimetres, or at least 12 millimetres. The aerosol-forming substrate may have a length of less than or equal to 20 millimetres, or less than or equal to 15 millimetres. For example, the aerosol-forming substrate may have a length of between 10 millimetres and 20 millimetres, or between 12 millimetres and 15 millimetres.

[0159] The aerosol-forming substrate may have a width, for example measured along the transverse axis or width direction of the aerosol-forming device, of at least 5 millimetres, or at least 6 millimetres. The aerosol-forming substrate may have a width of less than or equal to 10 millimetres, or less than or equal to 8 millimetres. For example, the aerosol-forming substrate may have a width of between 5 millimetres and 10 millimetres, or between 6 millimetres and 8 millimetres.The aerosol-forming substrate may have a depth or thickness, for example measured along the normal direction of the aerosol-forming device, of at least 2 millimetres, or at least 3 millimetres. The aerosol-forming substrate may have a depth or thickness of less than or equal to 5 millimetres, or less than or equal to 4 millimetres. For example, the aerosol-forming substrate may have a depth or thickness of between 2 millimetres and 5 millimetres, or between 3 millimetres and 4 millimetres, for example between 2.5 millimetres and 4 mm millimetres.

[0160] The aerosol-forming substrate may have a volume of at least 200 cubic millimetres, or at least 250 cubic millimetres. The aerosol-forming substrate may have a volume of less than or equal to 400 cubic millimetres, or less than or equal to 350 cubic millimetres. For example, the aerosol-forming substrate may have a volume of between 200 cubic millimetres and 400 cubic millimetres, or between 250 cubic millimetres and 350 cubic millimetres.

[0161] The main faces or surfaces of the aerosol-forming article may comprise or be made of a cover sheet, which may comprise paper-based material, for example rolling paper, which may be fixed to the frame and, together with the frame, may define the substrate chamber or cavity, which may be filled with any type of aerosol-forming substrate, in particular solid substrate material, for example in bulk form or in the form of a plurality of granules or beads. Accordingly, each of the main faces or surfaces of the aerosol-forming article may comprise or constitute a cover-sheet, which may be heated by the first heating device and / or the heating elements thereof.

[0162] A distance or separation between the two opposing heating elements of the first heating device may be such that the aerosol-forming article fits therebetween, and / or such that the two opposing heating elements contact the two opposing main faces of the article. Accordingly, a distance or separation between the heating elements, for example measured along the normal direction of the aerosol-forming device or article, may substantially correspond to, be equal to, match or be slightly smaller than the thickness of the aerosol-forming article, such that heating surfaces of the heating elements of the first heating device may contact the two opposing main faces of the aerosol-forming article, for example when the aerosol-forming article is inserted into the heating chamber. Alternatively or additionally, a distance or separation between the two opposing heating elements of the first heating device, for example as measured along the normal direction of the aerosol-forming device or article, may be between 1 mm and 10 mm, for example between 2 mm and 5 mm, preferably between 2.5 mm and 4 mm, more preferably about 3.1 mm.

[0163] The heating chamber and / or heating volume may be configured to at least partially receive the aerosol-forming article having a length, e.g. as measured along the insertion axis in longitudinal direction, and / or parallel to the longitudinal axis, in a range between 20 mm and 40 mm, preferably between 25 mm and 35 mm, more preferably about 30 mm, having a width, e.g. measured in transverse direction of the aerosol-forming device, in a range between 7 mm and 15 mm, preferably between 9 mm and 13 mm, more preferably about 11 mm, and a thickness orheight, e.g. measured in normal direction of the aerosol-forming device, of between 1 mm and 10 mm, for example between 2 mm and 5 mm, preferably between 2.5 mm and 4 mm, more preferably about 3.1 mm. Therein, the length may refer to a minimum, mean or maximum length, the width may refer to a minimum, mean or maximum width and the thickness may refer to a minimum, mean or maximum thickness, respectively, height of the aerosol-forming article.

[0164] The heating chamber and / or heating volume may be configured to have an insertion depth along the insertion axis in a range between 10 mm and 35 mm, preferably in a range between 15 mm and 30 mm, more preferably between 15 mm and 25 mm. The insertion depth may refer to a distance by which the aerosol-forming article can be inserted into the heating chamber and / or heating volume. The insertion depth may for example correspond to a distance, for example minimum, mean or maximum distance, between a proximal end face of the heating chamber or heating volume and a distal end face of the heating chamber or heating volume. The insertion depth may refer to a minimum, mean or maximum distance or insertion depth.

[0165] The insertion depth may define or substantially correspond to a length of the heating chamber and / or heating volume, for example measured in longitudinal direction of the aerosolforming device. Accordingly, a length of the heating chamber and / or heating volume may be in a range between 10 mm and 35 mm, preferably in a range between 15 mm and 30 mm, more preferably between 15 mm and 25 mm. The length may refer to a minimum, mean or maximum length.

[0166] The heating chamber and / or heating volume may be configured to have an insertion depth that is shorter than a length of the aerosol-forming article. Accordingly, the aerosol-forming article, when inserted into the heating chamber and / or heating volume, may protrude from a proximal end of the heating chamber or heating volume, for example by about 1 mm to 30 mm, for example 2 mm to 20 mm, preferably about 5 mm to 15 mm, more preferably about 5 mm to about 10 mm.

[0167] The heating chamber and / or heating volume may have a width, for example measured along the transverse direction of the aerosol-forming device, between the two inner small side faces or lateral faces between 7.2 mm and 15.2 mm, preferably between 9.2 mm and 13.2 mm, more preferably about 11.2 mm. The width may be minimum, mean or maximum width.

[0168] The heating chamber and / or heating volume may have a width, for example measured along the transverse direction of the aerosol-forming device, between the two inner small side faces or lateral faces to provide for an interference fit, a press-fit, or a friction-fit with the small side surfaces or lateral faces of aerosol-forming article. Hence, the aerosol-forming article may be laterally positioned or fixed in the heating chamber or heating volume.

[0169] The heating chamber and / or heating volume may have a height or thickness, for example measured along the normal direction of the aerosol-forming device, between two inner large side faces or main faces of a heater casing or heating elements between 2 mm and 10 mm, morepreferably between 3 mm and 8 mm, even more preferably between 4 mm and 6 mm. The height may be minimum, mean or maximum height.

[0170] The aerosol-forming device may further comprise a device body, also referred to as body or body part, defining a main axis of extension of the aerosol-forming device, which may be parallel to the longitudinal axis of the device and / or the insertion direction for inserting the aerosolforming article into the aerosol-forming device. The aerosol-forming device may further comprise a downstream element movably attached to the device body or body, such that the device body and the downstream element are movable relative to each other between an open position and a use position, wherein access to the heating chamber and / or heating volume is provided in the open position, such that the aerosol-forming article is removable from or insertable into the heating chamber and / or heating volume in the open position, and wherein the heating chamber and / or heating volume is closed in the closed position. The downstream element may also be referred to herein as mouthpiece portion, and may generally refer to a part of the device or the housing thereof that is displaceable or movable relative to the device body.

[0171] The downstream element of the aerosol-forming device may be slidably and / or rotatably attached or coupled to the device body, such that the downstream element is movable, for example relative to the device body, from the open position to the use position. The downstream element and the device body may be moved or displaced relative to each other along the longitudinal direction, parallel to the longitudinal axis between the open position and the use position, or in another direction.

[0172] The use position and the open position of the aerosol-forming device may generally refer to two different configurations of the aerosol-forming device. Also, the terms open position and closed position may be used herein with reference to one or more elements or components of the aerosol-forming device, thereby describing different configurations of said components or elements.

[0173] For example, between the open position and the use position, the device body may be moved or displaced relative to the downstream element of the aerosol-forming device. The device body may be moved relative to the downstream element, for example parallel to the longitudinal axis or along the longitudinal direction of the aerosol-forming device. The aerosol-forming device being in the open position, respectively, being in the closed position, may be interchangeably or synonymously used herein with the device body and / or downstream element being in the open position, respectively, being in the closed position.

[0174] In the use position, the heating chamber and / or heating volume may be closed and / or covered by the downstream element and the device body. Accordingly, the heating chamber and / or heating volume may not be accessible, respectively, may be inaccessible for a user to insert the aerosol-forming article or remove it therefrom. Alternatively or additionally, the aerosol-forming article may only be inserted into the heating chamber and / or heating volume when the device body and the downstream element are displaced or moved relative to each other out of the use position, for example are displaced towards the open position. Optionally, generation of aerosol may only be allowed in the use position.

[0175] In the open position, the heating chamber and / or heating volume may be accessible, for example for inserting an aerosol-forming article into or removing it from the heating chamber and / or heating volume

[0176] A relative displacement or movement of the device body and the downstream element from the open position towards or into the use position may refer to a displacement or movement of the downstream element from a proximal end towards a distal end of the aerosol-forming device, and / or may refer to a displacement or movement of the device body from a distal end towards a proximal end of the aerosol-forming device. Accordingly, the device body and the downstream element may be moved or displaced towards each other, for example along or parallel to the longitudinal axis of the aerosol-forming device, when moving the device body and the downstream element from the open position towards or into the use position. Alternatively or additionally, the device body and the downstream element may be moved or displaced away from each other, for example along or parallel to the longitudinal axis of the aerosol-forming device, when moving the device body and the downstream element from the use position towards or into the open position. Alternatively or additionally, the device body and the downstream element may be moved away from each other based on rotating at least one of the device body and the downstream element.

[0177] As used herein, the terms “distal” and “proximal” describe the locations of components or elements in relation to a user holding or using the aerosol-forming device, for example using the aerosol-forming device to consume or inhale aerosol. Therein, “distal” can refer to a location or element that is farther away from the user, and “proximal” can refer to a location or element that is closer to the user.

[0178] The aerosol-forming device may further comprise an interconnection mechanism arranged between the downstream element and the device body, and permitting the movement between the open and the use position, wherein the movement includes a rotational movement, a linear movement, or combination of a rotational and linear movement. In particular, any mechanism described herein for moving or displacing the device body and the downstream element relative to each other between the open position and use position can be used.

[0179] The aerosol-forming device may further comprise a heating module arranged at least partly in the device body, wherein the heating chamber and / or heating volume is arranged in the heating module, optionally, wherein the heating module is removable from the device body of the aerosolforming device.The heating module may be slidably arranged inside the device body to slide along the main axis of extension or longitudinal axis, wherein a spring biasing mechanism may optionally be configured to push the heating module to be at least partially outside the device body when the downstream element is in the open position. In other words, in the open position, the heating module may protrude from an end of the device body. For instance, this may allow to remove or replace the heating module.

[0180] The aerosol-forming device may further comprise an upstream fluidic interconnection element configured to provide a fluidic connection between the upstream airflow path upstream and the aerosol-forming article, wherein the upstream fluidic interconnection element comprises a blade structure surrounding the upstream airflow path along a central axis of the upstream airflow path, the blade structure having a first end configured to face an upstream air inlet of the aerosol-forming article, and a second end arranged opposite of the first end, wherein an outer wall of the blade structure has a sloped or tapered shape thereby increasing a thickness of the blade structure in a direction from the first end to the second end. In particular, the upstream fluidic interconnection element or its blade structure can be configured to cut or press into a wall or frame around an upstream air inlet of the aerosol-forming article, to provide for a fluidic connection and / or fluidic coupling between the upstream airflow path and the substrate of the aerosol-forming article.

[0181] By means of the blade structure of the upstream fluidic interconnection element cutting or pressing into the wall or frame surrounding the upstream air inlet, a substantially or at least partially sealed or fluid-tight coupling between the upstream airflow path and the substrate of the aerosol-forming article can be ensured or provided.

[0182] A cross-sectional area of an opening provided around an outer edge of the blade structure may be larger than a cross-sectional area of the upstream air inlet of the aerosol-forming article. This may ensure that the cross-sectional area of the upstream air inlet of the aerosol-forming article is not decreased by the blade structure at least partially pressing or cutting into the wall around or surrounding the upstream air inlet. Accordingly, the upstream air inlet may be kept open to let air pass therethrough.

[0183] A cross-sectional area of an opening provided around an outer edge of the blade structure may have one or more of a circular shape, an oval shape, a rectangular shape, and an irregular shape.

[0184] For example, a cross-sectional area of a flow path provided by the blade structure may have a rectangular shape with rounded corners. By means of the rectangular shape with rounded corners obstructions for air flowing therethrough may advantageously be avoided.

[0185] The aerosol-forming device may further comprise a downstream airflow path configured to provide an aerosol from the aerosol-forming article to an aerosol outlet of the device, and adownstream fluidic interconnection element configured to fluidically interconnect the downstream airflow path with the aerosol-forming article, wherein the downstream fluidic interconnection element includes a blade structure configured to cut or press into a wall around a downstream air outlet of the aerosol-forming article, to provide for a sealed fluidic connection between the aerosolforming article and the downstream airflow path.

[0186] By means of the blade structure of the downstream fluidic interconnection element cutting or pressing into the wall or frame surrounding the downstream air outlet, a substantially or at least partially sealed or fluid-tight coupling between the substrate of the aerosol-forming article and the downstream airflow path can be ensured or provided.

[0187] The downstream fluidic interconnection element, with or including the blade structure, may be in fluidic interconnection with the downstream airflow path and optionally with a mouthpiece of the aerosol-forming device, which mouthpiece may be movable relative to the heating chamber by either a rotational movement, a linear movement, or a combination of a rotational and linear movement. Accordingly, air flowing or passing through the downstream fluidic interconnection element with the associated blade structure may flow into downstream airflow path and optionally into the mouthpiece. In other words, the downstream fluidic interconnection element may guide the air or air flow from the aerosol-generating article and the downstream air outlet into the downstream airflow path and optionally into the mouthpiece, for example towards a user’s mouth.

[0188] The blade structure of the downstream fluidic interconnection element may be tapered or conical towards a center axis of the downstream airflow path, such that one or more tapered or conical walls of the blade structure are configured to press against an inner wall an inner wall of the aerosol-forming article, preferably wherein the blade structure of the downstream fluidic interconnection element forms a cutting end edge, such that the cutting end edge of the blade structure is configured to cut into the wall around a downstream aerosol outlet of the aerosolforming article. The downstream air outlet may also be referred to herein as aerosol outlet or downstream aerosol outlet of the aerosol-forming article.

[0189] The downstream and upstream fluidic interconnection elements may be formed and shaped corresponding to each other or identically, and may be arranged opposite to each other at the air inlet and aerosol outlet of the aerosol-forming article.

[0190] In an exemplary configuration, the upstream heating device may be arranged at least partly within, at, in thermal contact with or close to the upstream airflow path upstream. For instance, at least a part of the upstream heating device may protrude into the upstream airflow path, for example protrude from a wall of the upstream airflow path. Optionally, at least a part of a surface of the upstream heating device may be in direct contact with air in the upstream airflow path. Generally, this can allow to efficiently heat the air in the upstream airflow path, which can then heat the aerosol-forming article based on convective heating.In an example, at least a part or portion of the upstream airflow path upstream of the heating chamber or heating volume may be slit-like shaped. Hence, at least a part or portion of the upstream airflow path may be comparatively narrow, such that the airflow therethrough can be quickly and efficiently heated.

[0191] Alternatively or additionally, the upstream heating device may comprise a slit-shaped air channel and a resistive heating element or resistive heating device, for example a substantially or preferably planar resistive heating element, arranged inside the slit-shaped air channel, such that two narrow airflow channels are formed above and below the resistive heating element, respectively, on two opposite sides of the resistive heating element. The slit-shaped or slot shaped air channel may also be referred to herein as convective heating chamber. For instance, the air channels or gaps may be formed on two opposite sides, for example, on two planar sides or surfaces, of the resistive heating element.

[0192] By means of the upstream heating device with the resistive heating element, an efficient pre-heating or flash heating of the airflow may be ensured, for example such that air with elevated temperature can be directed into or towards the aerosol-forming article for generating aerosol.

[0193] The two narrow air flow channels (or air flow channels or gaps) may have a width in a range between 3 mm to 15 mm, and have a height of less than 0.5 mm and more than 0.05 mm, preferably less than 0.3 mm and more than 0.1 mm, preferably less than 0.25 mm to 0.1 mm. The width may, for example, be measured along the transverse or width direction of the aerosolforming device, and the height may be measured along the normal or height direction of the aerosol-forming device, or vice versa. Such dimensions, heights and / or widths may allow for an efficient and fast heating of the air flowing through the air flow channels.

[0194] In an example, two opposing walls forming the slit-shaped air channel of the upstream heating device and having the resistive element therebetween may not be heated. The walls may be made from an insulating material, avoiding heat transfer from the convective heating chamber into other parts of the device through other paths than the heated air flow. This may provide for efficient heating.

[0195] Generally, the configuration or design of the upstream heating device can ensure that the upstream heating device and / or its resistive heating element has a low thermal mass or generally low mass, which can allow to change its temperature based on a small airflow, while the walls of the convective heating chamber, respectively, the walls defining the slit-shaped air channel of the upstream heating device can have low thermal conductivity, to avoid taking on heat and thereby providing for a high thermal capacity to the upstream airflow path. Preferably, the walls should have a low thermal conductivity and a high specific heat capacity. Further, the walls should withstand the heat and comprise tox-appropriate material. For example, a ceramic material, zirconia, alumina or a combination thereof can be used for the walls defining the convectiveheating chamber and / or defining the walls of the slit-shaped air channel of the upstream heating device.

[0196] The two opposing walls forming the slit-shaped air channel of the upstream heating device and having the resistive element therebetween may have a structured, for example roughened or ragged, surface for causing an air flow turbulence. Additionally or alternatively, the surface of the resistive heating element may be structured, for example roughened or ragged, to cause turbulences. Also such air flow turbulence may be beneficial in terms of an efficient heating, for example as it may allow for a more homogenous temperature distribution.

[0197] An air flow direction in the upstream heating device may be in axis with an air flow direction in the heating chamber and / or heating volume. For example, the air flow direction may be substantially parallel or along the longitudinal axis of the aerosol-forming device and / or article. By being in axis, obstructions in the flow path can be avoided, thereby also potentially preventing overheating.

[0198] The resistive heating element of the upstream heating device may be formed as a meandering or serpentine structure, wherein the meandering or serpentine structure may extend in-plane of the resistive heating element. For example, the resistive heating element may extend in a plane, and the meandering or serpentine structure may be directed along an extension direction thereof in said plane, wherein portions of the meandering or serpentine structure may alternately traverse the actual extension direction of the meandering or serpentine structure. The extension direction of the meandering or serpentine structure may, for example, extend in a direction transverse to the longitudinal direction of the aerosol-forming device, for example along the transverse or normal direction thereof.

[0199] For example, the resistive heating element of the upstream heating device may comprise a strip of a metal sheet, for example stainless steel, which may be perforated and / or include one or more perforation openings or holes. In other words, the resistive heating element may comprise a meshed metal strip. The strip may be bent into a stack of serpentine branches spanning between the two terminals of the resistive heating element. The branches may all be formed similarly, for example by having the same dimensions and / or extensions. The direction in which the stack of serpentine branches extends may be referred to as the stack direction, and the stack direction may be perpendicular or parallel to the longitudinal axis or direction of the aerosolforming device. The resistive heating element may be configured and / or arranged so that the air flowing through the convective heating chamber passes through the perforations forming the mesh of the strip, particularly along the stack direction. By flowing along the stack direction, the air may pass through perforations of every single branch in the stack, which ensures efficient and quick heat transfer to the air in the upstream airflow path. Also this configuration or design can ensure that the upstream heating device and / or its resistive heating element has a low thermalmass or generally low mass, which can allow to change its temperature based on a small airflow in a short period of time. Hence, temperature changes, and thus user inhalations, can be detected quickly and reliably.

[0200] The heating chamber and / or heating volume of the aerosol-forming device may be configured to removably receive the aerosol-forming article, the aerosol-forming article having a substantially rectangular parallelepiped shape defining two opposing main faces and an aerosolforming substrate arranged between the opposing main faces. Therein, the heating device can comprise two opposing heating elements, for example resistive heating elements, forming a substantially rectangular parallelepiped heating volume therebetween for removably and at least partially receiving the aerosol-forming article, the heating volume arranged at least partially inside the heating chamber. Further, at least one of the two heating elements can be made of an electrically conductive material. Accordingly, at least one of, preferably both, the heating elements may be configured to heat the substrate or article.

[0201] In an example, both heating elements of the heating device can be made from electrically conductive material and both heating elements can be configured to heat the substrate or article from the two opposing main faces or surfaces of the aerosol-forming article. Optionally, the heating device may comprise one or two further heating elements which may be arranged opposite to each other in transverse direction and may be configured to heat the one or more lateral surfaces or faces of the aerosol-forming substrate.

[0202] The heating device and / or the heating elements thereof may be arranged inside the heating chamber and define the heating volume, wherein upon insertion of the aerosol-forming article into the heating chamber, at least a part of the heating device and / or at least one of the heating elements thereof can be configured to move towards an adjacent side face of the heating chamber so that at least one heating element is pressed against one of the main faces of the aerosolforming article. For example, at least a part of at least one of the heating elements may be moved by the insertion of the aerosol-forming article into the heating chamber.

[0203] Preferably, both heating elements can be moved towards the aerosol-forming article, such that both heating elements are pressed against a respective one of the main faces of the aerosolforming article. This can ensure good thermal contact between the one or both heating elements and the aerosol-forming article, thereby ensuring efficient heat transfer and heating of the substrate.

[0204] At least one of the heating elements, preferably both heating elements, of the heating device can include a heating plate formed as a meandering track in the shape of a leaf spring. Optionally, the at least one heating element, preferably both heating elements, of the heating device can include a heating plate with a plurality of parallelly-arranged heating tracks arranged in parallel to an insertion direction and / or longitudinal axis of the aerosol-forming device.The aerosol-forming device may further include a heater casing made of a non-conductive material forming an outer shell around the two opposing heating elements of the heating device. The heater casing may be part of a heater module or heating module of the aerosol-forming device. Therein, two smaller inner side faces or lateral faces of the heater casing may form or define the inner small side faces or lateral faces of the heating chamber and / or heating volume. Generally, the heater casing may insulate the housing or device body of the aerosol-forming device, such that heat dissipation can be reduced, for example such that the housing may not heat-up that much during a usage session and / or such that the heat is confined to the interior of the aerosol-forming device

[0205] For example, the two heating elements of the heating device may oppose each other in normal direction and the small or smaller inner side faces of the heater casing may refer to lateral faces of the inner casing that define or constitute two lateral faces of the heating chamber and / or heating volume, wherein the two lateral faces of the heater casing and / or the heating chamber may oppose each other in transverse direction of the aerosol-forming device.

[0206] According to a further aspect of the present disclosure, there is provided an aerosol-forming system comprising an aerosol-forming device, as described hereinabove and hereinbelow. The aerosol-forming system comprises one or both an aerosol-forming article for generating aerosol, and a companion device for charging and / or storing the aerosol-forming device.

[0207] As mentioned above, any disclosure herein related to the aerosol-forming device equally applies to the aerosol-forming system, and vice versa.

[0208] The companion device may also be referred to as charger case. The aerosol-forming device may be mechanically couplable to the companion device in order to store the aerosol-forming device and / or in order to charge an energy storage or power source of the aerosol-forming device via the companion device.

[0209] A mechanical coupling of the aerosol-forming device and the companion device may, in the context of the present disclosure, include a contact between a part or surface of the companion device and a part or surface of the aerosol-forming device. For instance, when coupling the aerosol-forming device with the companion device, a part of a housing or outer surface of the aerosol-forming device may be in contact or direct contact with a part of a housing, compartment or surface of the companion device. Accordingly, a mechanical coupling of the aerosol-forming device and the companion device can include a mechanical or physical contact between the aerosol-forming device and the companion device.

[0210] For example, the aerosol-forming device may be mechanically couplable to the companion device based on at least partly inserting the aerosol-forming device into the companion device, for example into a cavity, compartment or recess of the companion device. Alternatively oradditionally, the companion device may be mechanically couplable with the aerosol-forming device based on at least partly receiving the aerosol-forming device in the companion device.

[0211] In an exemplary configuration, the companion device may comprise a compartment, cavity or recess for at least partly receiving the aerosol-forming device, for example, such that the aerosol-forming device is at least partly encompassed in or surrounded by the companion device.

[0212] Alternatively or additionally, the aerosol-forming device may be mechanically couplable to the companion device based on attaching a housing of the aerosol-forming device to the companion device. To attach the housing to the companion device, the companion device may, for example, comprise engagement means configured to engage with the housing of the aerosolforming device or corresponding engagement elements formed at or by the housing of the aerosol-forming device.

[0213] The control circuitry of the aerosol-forming device or a dedicated charging circuitry of the aerosol-forming device may be configured to charge the energy storage or power source of the aerosol-forming device upon, based on or in response to mechanically coupling the aerosolforming device with the companion device.

[0214] According to a further aspect of the present disclosure, there is provided a method of controlling an aerosol-forming device or system comprising a heating device configured to heat at least a part of an aerosol-forming article to form aerosol, wherein the heating device comprises two opposing heating elements defining a heating volume therebetween that is configured to receive at least a part of the aerosol-forming article. The method comprises:

[0215] increasing a temperature of the heating elements in a first phase of a usage session from an initial temperature to a first target temperature, based on controlling a supply of power to the heating elements by a control circuitry of the aerosol-forming device; decreasing the temperature of the heating elements in a second phase of the usage session; and

[0216] increasing the temperature of the heating elements in a third phase of the usage session.

[0217] The aerosol-forming device may comprise the elements, functions and characteristics, as described hereinabove and hereinbelow. Accordingly, any disclosure herein related to the aerosol-forming device or system equally applies to the method, and vice versa.

[0218] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0219] Example 1 : An aerosol-forming device, comprising: a heating device configured to heat at least a part of an aerosol-forming substrate or article to form aerosol, wherein the heating device comprises at least two opposing heating elements defining a heating volume therebetweenthat is configured to receive at least a part of the aerosol-forming article; and control circuitry configured to control a temperature of at least one of the heating elements during a usage session based on controlling a supply of power from a power source of the aerosol-forming device to the heating device, wherein the control circuitry is configured to: increase the temperature of one of or both heating elements in a first phase of the usage session from an initial temperature to a first target temperature; decrease the temperature one of or both heating elements in a second phase of the usage session; and increase the temperature one of or both heating elements in a third phase of the usage session.

[0220] Example 2: The aerosol-forming device according to the preceding example, wherein the aerosol-forming article has a substantially rectangular parallelepiped shape defining two opposing main faces and two opposing side faces, the aerosol-forming article including an aerosol-forming substrate arranged between the two opposing main faces.

[0221] Example 3: The aerosol-forming device according to any one of the preceding examples, wherein the heating volume defined by the two opposing heating elements have a substantially rectangular parallelepiped shape and / or is configured to removably receive at least a part of a substantially rectangular parallelepiped shaped aerosol-forming article.

[0222] Example 4: The aerosol-forming device according to any one of the preceding examples, wherein the two heating elements are arranged and configured to heat two opposing main faces of the aerosol-forming article, when the aerosol-forming article is at least partly arranged in the heating volume.

[0223] Example 5: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature below the first target temperature.

[0224] Example 6: The aerosol-forming device according to the preceding example, wherein the control circuitry is configured to increase the temperature of heating elements in the third phase of the usage session from the second target temperature to a third target temperature above the second target temperature.

[0225] Example 7: The aerosol-forming device according to any one of the preceding examples, wherein a second target temperature of the second phase is in a range from about 200°C to about 290°C, in particular from about 210°C to about 280°C, for example from about 220°C to about 270°C, preferably from about 220°C to about 250°C; and / or

[0226] wherein a third target temperature of the third phase is in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.Example 8: The aerosol-forming device according to any one of the preceding examples, wherein the first target temperature is in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.

[0227] Example 9: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is further configured to: maintain the temperature substantially constant during a fourth phase of the usage session.

[0228] Example 10: The aerosol-forming device according to the preceding example, wherein the control circuitry is configured to increase the temperature of the heating elements in the third phase of the usage session from a second target temperature to a third target temperature above the second target temperature, and to substantially maintain the third target temperature during the fourth phase.

[0229] Example 11: The aerosol-forming device according to any one of the preceding examples, wherein a duration of the first phase of the usage session may be between about 2 seconds and about 75 seconds, for example between about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 35 seconds.

[0230] Example 12: The aerosol-forming device according to any one of the preceding examples, wherein a duration of the second phase of the usage session may be between about 2 seconds and about 100 seconds, for example between about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 30 seconds.

[0231] Example 13: The aerosol-forming device according to any one of the preceding examples, wherein a duration of the third phase of the usage session may be between about 50 seconds and about 800 seconds, for example between about 150 seconds and about 600 seconds, preferably between about 200 seconds and about 450 seconds.

[0232] Example 14: The aerosol-forming device according to any one of the preceding examples, wherein a duration of the third phase of the usage session is longer than a duration of the first phase and longer than a duration of the second phase of the usage session.

[0233] Example 15: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to control the temperature of the heating elements based on at least one heating profile defining a course of the temperature of the heating elements over time during the usage session, preferably wherein the at least one heating profile is stored in a data storage of the aerosol-forming device.

[0234] Example 16: The aerosol-forming device according to the preceding example, wherein the at least one heating profile is indicative of or defines one or more target temperatures of the heating elements with respect to time during the usage session.Example 16A: The aerosol-forming device according to Example 15 or 16, wherein temperatures indicated or defined by the heating profile are in the range from 125°C to 350°C.

[0235] Example 17: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to control the temperature of the heating elements based on a plurality of predetermined heating profiles, each defining one or more target temperatures of the heating elements with respect to time during the usage session.

[0236] Example 18: The aerosol-forming device according to the preceding example, wherein each heating profile defines a maximum duration for a usage session, and

[0237] wherein the control circuitry is configured to stop or decrease the supply of power to the heating elements upon reaching the maximum duration of the usage session defined in one of the heating profiles currently applied for the usage session.

[0238] Example 19: The aerosol-forming device according to example 17 or 18, wherein different heating profiles differ from each other in one or more of a maximum duration of a usage session and an average temperature of the heating elements during the usage session.

[0239] Example 20: The aerosol-forming device according to the preceding example, wherein the longer the maximum duration of a usage session associated with one of the heating profiles is, the lower is the average temperature of the heating elements during the respective usage session; and / or

[0240] wherein the shorter the maximum duration of a usage session associated with one of the heating profiles is, the higher is the average temperature of the heating elements during the respective usage session.

[0241] Example 21: The aerosol-forming device according to example 19 or 20, wherein a heating profile among the plurality of heating profiles that is associated with a longer maximum duration of a usage session than another heating profile among the plurality of heating profiles, is associated with a smaller average temperature of the heating elements than said other heating profile; and / or

[0242] wherein a heating profile among the plurality of heating profiles that is associated with a shorter maximum duration of a usage session than another heating profile among the plurality of heating profiles, is associated with a higher average temperature of the heating elements than said other heating profile.

[0243] Example 22: The aerosol-forming device according to any one of examples 17 to 21, wherein different heating profiles differ from one another at least partly in terms of one or more of the duration of the first phase, an average temperature of the heating elements during the first phase, a maximum temperature of the heating elements during the first phase, the duration of the second phase, an average temperature of the heating elements during the second phase, a maximum temperature of the heating elements during the second phase, a minimum temperatureof the heating elements during the second phase, the duration of the third phase of the usage session, an average temperature of the heating elements during the third phase, and a maximum temperature of the heating elements during the third phase.

[0244] Example 23: The aerosol-forming device according to any one any one of examples 17 to 22, wherein the control circuitry is configured to apply one of the plurality of heating profiles based on a user input at a user interface of the aerosol-forming device.

[0245] Example 24: The aerosol-forming device according to any one any one of examples 17 to 23, wherein the control circuitry is configured to apply one of the plurality of heating profiles based on a type of the aerosol-forming article.

[0246] Example 25: The aerosol-forming device according to any one of examples 17 to 24, further comprising at least one sensor for determining a type of the aerosol-forming article, and wherein the control circuitry is configured to apply one of the plurality of heating profiles based on determining the type of aerosol-forming article by means of the at least one sensor.

[0247] Example 26: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature upon determining that the heating elements have reached the first target temperature.

[0248] Example 27: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to increase the temperature of the heating elements in the third phase of the usage session from a second target temperature to a third target temperature upon determining that the heating elements have reached the second target temperature.

[0249] Example 28: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to maintain, in a fourth phase of the usage session, a third target temperature of the heating elements upon determining that the heating elements have reached the third target temperature.

[0250] Example 29: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature upon determining that a predetermined duration of the first phase has elapsed.

[0251] Example 30: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to increase the temperature of the heating elements in the third phase of the usage session from a second target temperature to a third target temperature upon determining that a predetermined duration of the second phase has elapsed.Example 31: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to terminate the usage session upon determining that a predetermined duration of the third phase or a fourth phase has elapsed.

[0252] Example 32: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to maintain the temperature of the heating elements at a third target temperature reached in the third phase of the usage session for a predetermined duration of a fourth phase of the usage session upon determining that a predetermined duration of the third phase has elapsed.

[0253] Example 33: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to control the supply of power to both heating elements, such that the temperatures of both heating elements are substantially equal.

[0254] Example 34: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to control the temperature of the heating elements based on controlling one or more of an electrical voltage supplied to the heating elements or an induction coil, an electrical current supplied to the heating elements or an induction coil, and a frequency of an alternating electric field generated between the two opposing heating elements.

[0255] Example 35: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to determine the temperature of the heating elements based on determining an electrical resistance of the heating elements.

[0256] Example 36: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to regulate or control the temperature of the heating elements based on determining an electrical resistance of the heating elements.

[0257] Example 37: The aerosol-forming device according to example 35 or 36, wherein the two heating elements are connected in series, and wherein the control circuitry is configured to regulate or control the temperature of one or both heating elements based on determining the total electrical resistance of both heating elements.

[0258] Example 38: The aerosol-forming device according to the preceding example, wherein the control circuitry is configured to determine the total electrical resistance of both heating elements based on determining a voltage and a current supplied to the heating device.

[0259] Example 39: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to regulate or control the temperature of the heating elements based on determining an electrical resistance of the heating elements and based on one or more predetermined calibration values associating the electrical resistance with a temperature of the heating elements.Example 40: The aerosol-forming device according to the preceding example, wherein the one or more calibration values are stored in a data storage of the aerosol-forming device.

[0260] Example 41: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to initiate the usage session and / or increase the temperature of the heating elements from the initial temperature to the first target temperature in response to one or more of:

[0261] a sensor signal of at least one sensor of the aerosol-forming device;

[0262] insertion of an aerosol-forming article at least partly into the aerosol-forming device; coupling of an aerosol-forming article to the aerosol-forming device;

[0263] mechanical decoupling of the aerosol-forming device from a companion device; and a control signal from one or more user interfaces triggered by a user of the aerosol-forming device.

[0264] Example 42: The aerosol-forming device according to any one of the preceding examples, wherein the heating device includes a conductive heating device configured to heat the substrate of the aerosol-forming article by conductive heating.

[0265] Example 43: The aerosol-forming device according to any one of the preceding examples, wherein the two opposing heating elements include resistive heating elements configured to be resistively heated, and / or

[0266] wherein the two opposing heating elements include susceptors configured to be inductively heated.

[0267] Example 43A: The aerosol-forming device according to any one of the preceding examples, wherein a distance or separation between the two opposing heating elements of the heating device may be such that the aerosol-forming article fits therebetween and / or such that the two opposing heating elements contact the two opposing main faces of the article.

[0268] Example 43B: The aerosol-forming device according to any one of the preceding examples, wherein a distance or separation between the two opposing heating elements of the heating device is between 1 mm and 10 mm, for example between 2 mm and 5 mm, preferably between 2.5 mm and 4 mm, more preferably about 3.1 mm.

[0269] Example 45: The aerosol-forming device according to any one of the preceding examples, wherein the heating device is configured to continuously heat the aerosol-forming article during the usage session.

[0270] Example 46: The aerosol-forming device according to any one of the preceding examples, further comprising:

[0271] an upstream airflow path arranged upstream of the heating device, wherein the upstream airflow path is in fluid communication with an external environment of the aerosol-forming device,such that air is drawable by a user in a user inhalation from the external environment through the upstream airflow path towards the heating volume; and

[0272] an upstream heating device arranged in thermal contact with the upstream airflow path and configured to convectively heat air in the upstream airflow path to heat at least heat a part of a substrate of the aerosol-forming article.

[0273] Example 47: The aerosol-forming device according to the preceding example, wherein the upstream heating device is configured to perform a puff-on-demand heating operation; and / or wherein the control circuitry is configured to control the upstream heating device to perform a puff-on-demand heating operation.

[0274] Example 48: The aerosol-forming device according to any one of the preceding examples, further comprising a puff sensor configured to detect a user inhalation at the aerosolforming device.

[0275] Example 49: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to determine a user inhalation at the aerosolforming device based on determining a change in a temperature of at least one of the heating device and an upstream heating device arranged in thermal contact with an upstream airflow path of the aerosol-forming device.

[0276] Example 50: The aerosol-forming device according to any one of examples 46 to 49, wherein the control circuitry is configured to control a supply of power to the upstream heating device based on detecting a user inhalation at the aerosol-forming device.

[0277] Example 51 : The aerosol-forming device according to any one of examples 46 to 50, wherein the control circuitry is configured to supply electrical power to the upstream heating device in response to detecting a user inhalation at the aerosol-forming device.

[0278] Example 52: The aerosol-forming device according to any one of examples 46 to 51, wherein the control circuitry is configured to, in response to detecting a user inhalation at the aerosol-forming device, increase a temperature of the upstream heating device to a target temperature for the upstream heating device.

[0279] Example 53: The aerosol-forming device according to the preceding example, wherein the target temperature of the upstream heating device is in a range from about 270°C to about 500°C, for example from about 270°C to about 450°C, or for example from about 270°C to about 320°C, in particular from about 280°C to about 310°C, preferably about 300°C.

[0280] Example 54: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to increase the temperature of the heating elements in response to detecting a user inhalation at the aerosol-forming device; and / or wherein the control circuitry is configured to increase or boost the temperature of the heating elements during a user inhalation at the aerosol-forming device.Example 55: The aerosol-forming device according to any one of examples 46 to 54, wherein the control circuitry is configured to decrease or stop a supply of electrical power to the upstream heating device in response to detecting that a user inhalation at the aerosol-forming device has ended.

[0281] Example 56: The aerosol-forming device according to any one of the preceding examples, wherein the control circuitry is configured to control the temperature of the upstream heating device based on at least one predetermined heating profile defining at least one target temperature of the upstream heating device, to which the upstream heating device is to be heated during a user inhalation.

[0282] Example 57: The aerosol-forming device according to the preceding example, wherein the at least one heating profile of the upstream heating device defines one or more user inhalations of a usage session, during which one or more user inhalations a power supplied to the upstream heating device is smaller than a power supplied during other user inhalations of the usage session.

[0283] Example 58: The aerosol-forming device according to the preceding example, wherein said one or more user inhalations are one or more user inhalations during one of the first phase and the second phase of the usage session, preferably during the first phase of the usage session.

[0284] Example 59: The aerosol-forming device according to example 57 or 58, wherein said one or more user inhalations correspond to the first one or more user inhalations during a usage session.

[0285] Example 60: The aerosol-forming device according to any one of examples 46 to 59, wherein the control circuitry is configured to control the temperature of the heating elements based on at least one predetermined heating profile associated with the heating device, and wherein the control circuitry is configured to control the temperature of the upstream heating device based on at least one predetermined heating profile associated with the upstream heating device, and

[0286] wherein the at least one predetermined heating profile associated with the heating device differs from the at least one heating profile associated with the upstream heating device.

[0287] Example 61 : The aerosol-forming device according to any one of examples 46 to 60, wherein the aerosol-forming device comprises a main air inlet configured to receive an airflow from the external environment of the aerosol-forming device, wherein the main air inlet is in fluid communication with the upstream airflow path.

[0288] Example 62: The aerosol-forming device according to any one of the preceding examples, further comprising:a device body defining a main axis of extension of the aerosol-forming device and / or defining an insertion direction for inserting the aerosol-forming article into the aerosol-forming device; and

[0289] a downstream element movably attached to the device body, such that the device body and the downstream element are movable relative to each other between an open position and a use position, wherein access to the heating volume and / or heating chamber is provided in the open position, such that the aerosol-forming article is removable from or insertable into the heating volume and / or heating chamber, and wherein the heating volume and / or heating chamber is closed in the closed position.

[0290] Example 63: The aerosol-forming device of the previous example, further comprising: an interconnection mechanism arranged between the downstream element and the device body, and permitting the movement between the open and the use position, wherein the movement includes a rotational movement, a linear movement, or combination of a rotational and linear movement.

[0291] Example 64: The aerosol-forming device according to any one of the preceding examples, further comprising a heating module arranged at least partly in a device body, wherein the heating volume is arranged in the heating module, optionally, wherein the heating module is removable from the device body of the aerosol-forming device.

[0292] Example 65: The aerosol-forming device according to any one of examples 46 to 64, wherein the upstream heating device is arranged in the upstream airflow path upstream of the heating volume, preferably wherein the upstream airflow path upstream of the heating volume is slit-like shaped.

[0293] Example 66: The aerosol-forming device according to any one of examples 46 to 65, wherein the upstream heating device comprises a slit-shaped or slit-like shaped air channel and a resistive heating element, for example a substantially or preferably planar resistive heating element, arranged inside the slit-shaped air channel, such that two narrow air flow channels are formed above and below the resistive heating element.

[0294] Example 67: The aerosol-forming device according to the preceding example, wherein the resistive heating element of the upstream heating device is formed as a meandering or serpentine structure, extending in-plane of the resistive heating element.

[0295] Example 68: The aerosol-forming device according to example 66 or 67, wherein the resistive heating element is formed from a single sheet of metal; and / or wherein the resistive heating element comprises at least one strip of a metal sheet, optionally wherein the strip of metal sheet is perforated and / or includes one or more perforation openings or holes.

[0296] Example 69: The aerosol-forming device according to any one of examples 66 to 68, wherein the resistive heating element comprises at least one strip of a metal sheet, the at leastone strip being bent or formed into a stack of a plurality of serpentine-like formed branches, preferably the branches of the stack spanning between two terminals of the resistive heating element; and optionally wherein the stack extends along a stack direction perpendicular or parallel to a longitudinal axis of the aerosol-forming device.

[0297] Example 70: An aerosol-forming system comprising an aerosol-forming device according to any one of the preceding examples and one or more of: an aerosol-forming article for generating aerosol; and a companion device for one or more of storing the aerosol-forming device and charging the aerosol-forming device.

[0298] Example 71 : A method of controlling an aerosol-forming device or system comprising a heating device configured to heat at least a part of an aerosol-forming article to form aerosol, wherein the heating device comprises two opposing heating elements defining a heating volume therebetween that is configured to receive at least a part of the aerosol-forming article, the method comprising: increasing a temperature of the heating elements in a first phase of a usage session from an initial temperature to a first target temperature, based on controlling a supply of power to the heating elements by a control circuitry of the aerosol-forming device; decreasing the temperature of the heating elements in a second phase of the usage session; and increasing the temperature of the heating elements in a third phase of the usage session.

[0299] Examples will now be further described with reference to the figures in which:

[0300] Figure 1 shows an aerosol-forming system comprising an aerosol-forming device;

[0301] Figure 2 shows an aerosol-forming article;

[0302] Figure 3 shows an aerosol-forming article;

[0303] Figure 4 shows a schematic exploded view of a heating module for an aerosol-forming device;

[0304] Figure 5 shows a schematic exploded view of a heating module and heating chamber for an aerosol-forming device;

[0305] Figure 6 shows a schematic exploded view of a heating module for an aerosol-forming device;

[0306] Figure 7 shows a cross-sectional view of a heater module and an upstream heating device for an aerosol-forming device;

[0307] Figure 8 illustrates an airflow path through the aerosol-forming device;

[0308] Figure 9 illustrates a heating profile for a heating device of an aerosol-forming device; Figure 10 illustrates a heating profile for a heating device of an aerosol-forming device; Figure 11 illustrates a heating profile for a heating device of an aerosol-forming device; Figure 12 illustrates a heating profile for an upstream heating device of an aerosol-forming device;Figure 13 illustrates a heating profile for an upstream heating device of an aerosol-forming device; and

[0309] Figure 14 shows a flow chart illustrating a method of controlling an aerosol-forming device or system.

[0310] Herein, identical reference numerals are used, where possible, to designate identical elements that are common to the figures. Also, the images in the drawings are simplified and schematic for illustration purposes and may not be depicted true to scale.

[0311] The present disclosure shows and describes several embodiments which may comprise alternative or supplementary solutions for specific cases or considerations. However, it is noted that the present disclosure pertains to a complete device which may comprise any combination of features described herein. In particular, Figures 1 to 14 show and illustrate exemplary aerosolforming systems, aerosol-forming devices and / or various components, elements, and features thereof. While some of Figures 1 to 14 may show some elements or components in greater detail and according to an exemplary embodiment, the variations, examples and embodiments of Figures 1 to 14 can be combined with each other. Especially, it is noted that any of the features of any of the described embodiments may be freely combined with any other features of any other embodiments of the present disclosure. The disclosure is presented in embodiments for explanatory purposes only, and the presentation as specific embodiments does not mean that the features of one embodiment may not be complementary to other features, for example of other embodiments.

[0312] In the following, it can be mutually referred to any of Figures 1 to 14 which each show and illustrate exemplary aerosol-forming systems, aerosol-forming devices, one or more components, one or more features or one or more functions thereof.

[0313] Figure 1 shows an aerosol-forming system 4 for generating aerosol, for example for consumption or inhalation by a user in one or more usage sessions. The system 4 may comprise an aerosol-forming device 1 or aerosol-generating device 1 for generating aerosol and optionally a companion device 3 for at least partially receiving the aerosol-forming device 1. The companion device 3 may be a charging device for charging the aerosol-forming device 1 and / or an energy storage 15 or battery thereof.

[0314] The aerosol-forming device 1 may comprise an insertion opening for at least partially inserting an aerosol-forming article or aerosol-generating article 20, which is explained in more detail below with reference to Figures 2 and 3. The aerosol-forming article 20 may comprise an aerosol-forming substrate 23, such as a tobacco containing substrate and / or other active ingredient. The aerosol may be inhaled by a user, optionally using a mouthpiece 901. The aerosol may contain nicotine.The aerosol-forming device 1 may further include processing circuitry or control circuitry 5, for example with at least one processor, microcontroller or controller 17. For generating aerosol during use or consumption of the aerosol-forming article 20, the aerosol-forming device 1 may comprise a heating device 6a, which may also be referred to herein as first heating device 6a of the aerosol-forming device 1 or system 4, arranged at a heating chamber 30 of the aerosolforming device 1. The heating chamber 30 may comprise or define a heating volume 30a. As will be explained in greater detail hereinbelow, the heating chamber 30 and / or heating volume 30a can be sized and shaped to accommodate or receive at least a part of the aerosol-forming article 20 to heat the substrate 23.

[0315] The heating device 6a can be configured to perform a first heating operation to heat the substrate 23. For example, the heating device 6a may be configured to heat the substrate 23 or article 20 by or based on conductive heating in a continuous heating operation during a usage session.

[0316] For this purpose, the heating device 6a can comprise at least one, preferably two heating elements 6, 7 or a heater device for applying heat to at least a portion of the aerosol-forming substrate 23 and / or at least a part of the aerosol-forming article 20. Instead of the heating element 6, 7, a non-heat or non-thermal aerosolization device can be used, for example an ultrasonic device (not shown) may also be used to generate aerosol from the aerosol-forming article.

[0317] In particular, the heating device 6a can comprise two opposing heating elements 6, 7, which are spaced apart from each other to form the heating volume 30a therebetween, and to receive the aerosol-forming article 20 for aerosol consumption.

[0318] The control circuitry 5 and / or the processor 17 may be configured to control actuation, activation and / or deactivation of the heating device 6a and / or of the heating elements 6, 7.

[0319] In the following, heating elements 6, 7 will be described with a focus on resistive heating elements 6, 7, also referred to herein as Joule-type heating elements. However, the heating device 6a does not necessarily have to be a resistive / Joule-type heater heating device, but other heating means or approaches can be used, as also described herein. For instance, the heating elements 6, 7 may alternatively be configured as inductive heaters, or radiation-based heaters such as infrared heaters. It is possible that the two heating elements 6, 7 may be acting as external susceptors to the substrate that are heated by one or more coils wound around the two heating elements 6, 7 supplied with an AC voltage, for example a coil, induction coil or heating coil that is part of a heater casing 35, as will be described hereinbelow. The coil axis may coincide with the insertion axis for the aerosol-forming article 20 into the heating chamber 30 or heating volume 30a. The features described for the heating device 6a and / or the optionally resistive heating elements 6, 7 herein may also be applicable to these alternatives.The aerosol-forming device 1 exemplary shown in Figure 1 may comprise an upstream heating device 70 arranged upstream of the heating chamber 30 and in thermal contact with an upstream airflow path 40a. The upstream heating device 70 may be optional only and may provide supplementary heating. The upstream airflow path 40a is arranged upstream of the heating chamber 30 or heating volume 30a, and fluidly connected or coupled to a surrounding, exterior or external environment of the aerosol-forming device 1 via one or more air inlets 46, also referred to herein as main air inlet 46 or device air inlet 46. When a user performs a user inhalation, air can be drawn by the user through the optional mouthpiece 901 or an end of the device 1, wherein the mouthpiece 901 or end of the device 1 can be fluidly coupled to the upstream airflow path 40a and air inlet 46, such that fresh air is drawn via the air inlet 46 through the upstream airflow path 40a and towards the upstream heating device 70, the heating chamber 30 and / or the heating volume 30a. As will be described in greater detail hereinbelow with reference to Figure 8, for example, the upstream airflow path 40a may be a section or part of a complex or multi-section airflow path structure in the aerosol-forming device 1.

[0320] As the upstream heating device 70 is in thermal contact with the upstream airflow path 40a, the upstream heating device 70 can heat the airflow towards the heating chamber 30 and aerosolforming article 20.

[0321] Also, since the upstream heating device 70 as well as the heating device 6a are subject to a changes in the airflow caused by the user inhalation, a temperature or change in the temperature of one or both the first heating device 6a and upstream heating device 70 can be used by the control circuitry 5 to detect one or more of a start, onset, occurrence, duration, end and termination of a user inhalation.

[0322] The upstream heating device 70 can be configured to perform a second heating operation, which may differ from the first heating operation performed by the heating device 6a. For example, the heating device 6a may be configured to provide a continuous heating to the aerosol-forming article 20 or substrate 23 during a usage session, and the upstream heating device 70 may be configured for a puff-on-demand heating, which can mean that the upstream heating device 70 can be activated, operated, and / or powered by the control circuitry 5 in accordance or correspondence with occurrence of a user inhalation or puff.

[0323] Further, the upstream heating device 70 may be particularly configured to heat the aerosolforming article 20 and / or substrate 23 based on convection. This can mean that the upstream heating device 70 is configured to heat the airflow in the upstream airflow path 40a towards the heating chamber 30 and indirectly heat the aerosol-forming substrate 23 or article 20 via the heated airflow. Therefore, the upstream heating device 70 may also be referred to herein as upstream heating device 70 or convective heater assembly 70. In a non-limiting example, the upstream heating device 70 may include at least one resistive heating element 71 to heat theairflow in the airflow path 40a. Other heating means or elements can be used instead or in addition. Details of an exemplary upstream heating device 70 with resistive heating element 71 is shown in Figure 7.

[0324] For powering the heating device 6a, the at least one heating element 6, 7, and / or the upstream heating device 70 with electrical power, the aerosol-forming device 1 may further comprise at least one energy storage 15 or power source 15, for example in the form of a removable and / or rechargeable battery, for storing electrical energy or power.

[0325] The control circuitry 5 can be configured to control one or more of the energy storage 15, power source 15, the heating device 6a, the at least one heating element 6, 7, and the upstream heating device 70, for example to heat the aerosol-forming substrate 23 or article 20 in a usage session. In particular, the control circuitry 5 can be configured to control a supply of electrical power from the energy source 15 to the heating device 6a and / or the upstream heating device 70, thereby controlling the heating, a heating operation, activation and / or deactivation of the heating device 6a and / or the upstream heating device 70.

[0326] Both the aerosol-forming device 1 and the companion device 3 may each comprise an energy storage 15, 15a and the energy storage 15, 15a may be electrically coupled to the respective device 1, 3. In particular, energy storages 15, 15a may be removably couplable to the aerosol-forming device 1 and / or the companion device 3. In other words, energy storages 15, 15a may be a replaceable energy storages or batteries. The connection between the energy storages 15, 15a and the respective devices 1 , 3 may be configured so that the devices 1 , 3 may be run by electrical energy provided by the respective energy storage 15, 15a. Additionally, the connection between the energy storages 15, 15a and the aerosol-forming device 1 and / or the companion device 3 may be configured so that data may be transmitted between the processing or control circuitries of the aerosol-forming device 1 and / or the companion device 3 and the energy storages 15, 15a.

[0327] The aerosol-forming device 1 may further comprise at least one electrical connector 12 for coupling to a corresponding at least one electrical connector 13 of the companion device 3 and / or an electrical connector of an external power supply (not shown), e.g., a USB connector with a USB charger. In an example, energy storage 15 of the aerosol-forming device 1 may be charged based on coupling the device 1 to the companion device 3, for example based on at least partly inserting the device 1 into a compartment or recess of the companion device 3. Upon mechanically coupling the devices 1, 3, an electrical connection between the one or more electrical connectors 12 of the aerosol-forming device 1 may be coupled with the one or more electrical connectors 13 of the companion device 3 to charge the energy storage 15 of the aerosolforming device 1 via the energy storage 15a of the companion device 3. The energy storage 15aof the companion device 3 can, for example, be re-charged via connection to a main power supply, e.g., a USB charger. Any of the charging processes can also be performed wirelessly.

[0328] The aerosol-forming device 1 may further comprise a communications arrangement 9 or communication circuitry 9 with one or more communications interfaces 10 for communicatively coupling the aerosol-forming device 1 with the companion device 3, server, smartphone or other devices, for example, via an Internet connection, a wireless LAN connection, a WiFi connection, a Bluetooth connection, a mobile phone network, a mobile data connection for example but not limited to a 3G / 4G / 5G connection, an edge connection, an LTE connection, a BUS connection, a wireless connection, a wired connection, an optical data connection such as but not limited to IrDa, a radio connection, a near field connection, and / or an loT connection.

[0329] The aerosol-forming device 1 may further comprise a data storage 11 or memory for storing information, program code or data. Data storage 11 may also store collected values of sensors and / or one or more mathematical functions or formulas, software and computer instructions that can be executed by the control circuitry 5 and / or processor 17. One or more sensors 16 may be arranged on, at or in the aerosol-forming device 1 or the companion device 3 to collect data. One or more of the sensors 16 may for example be temperature sensors, strain sensors, accelerometers or any other suitable sensors.

[0330] The aerosol-forming device 1 may further comprise user interface components, for example comprising an input element or input device 19, for example in the form of a pushbutton, touch display or a capacitive button. The input device 19 may be used as a power button to activate or deactivate the heating device 6a and / or the upstream heating device 70 thereby to activate or deactivate the aerosol-forming device 1.

[0331] Upon activation of the aerosol-forming device 1, the heating device 6a and optionally the upstream heating device 70 may be activated and heat may be applied to at least a part of the aerosol-forming article 20, such that aerosol can be generated for consumption or inhalation by the user, for example in a usage session. The actual control or operation of the heating device 6a and the upstream heating device 70 will be described in more detail hereinbelow.

[0332] The aerosol generating device 1 and / or the companion device 3 may each comprise one or more output elements, such as a display device 18 and / or one or more LEDs, for outputting a signal and / or displaying information to a user, for example a user interface such as a GUI, or haptic and acoustic data output devices. The display device 18 may be, for example, a touchscreen and may therefore be configured as both an output and an input element.

[0333] Figure 2 shows three different views of an exemplary aerosol-forming article 20, or consumable, which may be used with the aerosol-forming device 1 of Figure 1 or any of the other figures. In the top left, an end view is shown. Bottom left shows a perspective view, and the right side of Figure 2 shows a side view of the aerosol-forming article 20. A further detailed view of theaerosol-forming article 20 of Figure 2 is shown in Figure 3, which shows a perspective view at the top of Figure 3 and a cross-sectional view along a longitudinal axis A-A at the bottom of Figure 3.

[0334] Although the present disclosure is applicable to conventional and not limited in use of rectangular parallelepiped shaped aerosol-forming articles, Figures 2 and 3 and many other Figures illustrate an aerosol-forming article 20 that may have a flat or planar shape. Other shapes or geometries of the aerosol-forming article 20 are possible and encompassed by the present disclosure.

[0335] The aerosol-forming article shown in Figures 2 and 3, for example, can have the basic shape or footprint of a rectangle, optionally with rounded corners. For instance, the aerosolforming article 20 may be a cuboid or parallelepiped or rectangular parallelepiped, optionally with rounded corners. It may have a length L which is greater than its width W, which is in turn greater than its thickness T.

[0336] For example, the length L of the aerosol-forming article 20 may be from 20 mm to 40 mm, for example from 25 mm to 35 mm. In a non-limiting example, the length L of the aerosol-forming article 20 may be 30 mm. The width W of the aerosol-forming article 20 may be from 7 mm to 15 mm, for example from 9 mm to 13 mm. In a non-limiting example, the width W of the aerosolforming article 20 may be 11 mm. The thickness T of the aerosol-forming article 20 may be from 1 mm to 10 mm, for example 2 mm to 5 mm, for example from 2.5 mm to 4 mm. In a non-limiting example, the thickness T of the aerosol-forming article 20 may be 3.1 mm.

[0337] The aerosol-forming article 20 may comprise a frame 21 and an aerosol-forming substrate 23, which may be arranged in a centre section of the article 20 The centre section of the article 20 may also be referred to as central section or middle section of the article 20. The frame 21 may comprise or be made of a cellulose fibre material, for example a cardboard material. The frame 21 may define the circumference or perimeter of the aerosol-forming article 20 along the edges and / or corners.

[0338] The aerosol-forming article 20 comprises two opposing sides, surfaces or main faces 20a, 20b that make up the majority of the surface of the aerosol-forming article 20. The main faces or surfaces 20a, 20b may comprise or be made of a cover sheet, which may comprise paper-based material, for example rolling paper, which may be fixed to the frame 21 and, together with the frame 21, may define a substrate chamber 22 or cavity 22, which may be filled with any type of aerosol-forming substrate or capsule mentioned herein, or a combination of one or more substrate and a capsule. In particular, solid substrate material may be used. The substrate 23 material may be heated via the covers or cover sheets on the main faces 20a, 20b of the article 20.

[0339] The aerosol-forming substrate 23 may comprise a plurality of granules or beads of substrate material, wherein a bulk density of the aerosol-forming substrate 23 may be in a range of about 0.4 g / cm3to about 0.8 g / cm3, preferably about 0.6 g / cm3. Therein, the bulk density may be definedas the mass of the particles divided by the total volume they occupy. This volume can include the space between granules or beads as well as the space within the particles themselves.

[0340] The aerosol-forming substrate 23 may comprise a plurality of granules or beads of substrate material, wherein a density of single granules or beads of the substrate may be at least 0.75 grams per cubic centimetre, more preferably at least 0.8 grams per cubic centimetre, more preferably at least 0.9 grams per cubic centimetre, more preferably at least 1 gram per cubic centimetre, more preferably at least 1.1 grams per cubic centimetre, more preferably at least 1.2 grams per cubic centimetre.

[0341] The aerosol-forming substrate 23 may comprise a plurality of granules or beads of substrate material, wherein a density of single granules or beads of the substrate of the may be less than or equal to 2 grams per cubic centimetre, more preferably less than or equal to 1.95 grams per cubic centimetre, more preferably less than or equal to 1.9 grams per cubic centimetre, more preferably less than or equal to1.85 grams per cubic centimetre, more preferably less than or equal to 1.8 grams per cubic centimetre.

[0342] The cavity 22 or substrate chamber 22 of the aerosol-forming article 20 may be configured and / or arranged to accommodate or receive the aerosol-forming substrate 23. In particular, the cavity 22 may be at least partially, preferably entirely filled with aerosol-forming substrate 23, for example a plurality of granules or beads, or bulk material.

[0343] The cavity 22 and / or substrate 23 may have a length, for example measured along the longitudinal axis of the aerosol-forming article 20 or device, of at least 10 millimetres, or at least 12 millimetres. The cavity 22 and / or substrate 23 may have a length of less than or equal to 20 millimetres, or less than or equal to 15 millimetres. For example, the cavity 22 and / or substrate 23 may have a length of between 10 millimetres and 20 millimetres, or between 12 millimetres and 15 millimetres.

[0344] The cavity 22 and / or substrate 23 may have a width, for example measured along the transverse axis or width direction of the aerosol-forming device, of at least 5 millimetres, or at least 6 millimetres. The cavity 22 and / or substrate 23 may have a width of less than or equal to 10 millimetres, or less than or equal to 8 millimetres. For example, the cavity 22 and / or substrate 23 may have a width of between 5 millimetres and 10 millimetres, or between 6 millimetres and 8 millimetres.

[0345] The cavity 22 and / or substrate 23 may have a depth or thickness, for example measured along the transverse axis or thickness direction of the aerosol-forming device, of at least 2 millimetres, or at least 3 millimetres. The cavity 22 and / or substrate 23 may have a depth of less than or equal to 5 millimetres, or less than or equal to 4 millimetres. For example, the cavity 22 and / or substrate 23 may have a depth of between 2 millimetres and 5 millimetres, or between 3 millimetres and 4 millimetres.The cavity 22 and / or substrate 23 may have a volume of at least 200 cubic millimetres, or at least 250 cubic millimetres. The cavity 22 and / or substrate 23 may have a volume of less than or equal to 400 cubic millimetres, or less than or equal to 350 cubic millimetres. For example, the cavity 22 and / or substrate 23 may have a volume of between 200 cubic millimetres and 400 cubic millimetres, or between 250 cubic millimetres and 350 cubic millimetres. The cavity 22 may substantially be completely filled with substrate material, for example a plurality of beads or granules. Accordingly, the dimensions of the cavity may correspond to dimensions, volumes and sizes of the aerosol-forming substrate.

[0346] The main faces or surfaces 20a, 20b of the aerosol-forming article 20 may comprise or be made of a cover sheet, which may comprise paper-based material, for example rolling paper, which may be fixed to the frame 21 and, together with the frame 21, may define the substrate chamber 22 or cavity 22, which may be filled with any type of aerosol-forming substrate 23, in particular solid substrate material, for example in bulk form or in the form of a plurality of granules or beads. Accordingly, each of the main faces or surfaces 20a, 20b of the aerosol-forming article 20 may comprise or constitute a cover-sheet, which may be heated by the first heating device 6a and / or the heating elements 6, 7 thereof.

[0347] The present disclosure provides an aerosol-forming device 1 which may be configured to use such an aerosol-forming article 20. In particular, the heating chamber 30 and / or heating volume 30a of the aerosol-forming device 1 may be configured, shaped and arranged to removably accommodate or receive a rectangular parallelepiped shaped aerosol-forming article 20, as described herein. Optionally, the heating chamber 30 and / or heating volume 30a may be defined by or comprise a heating module 34 configured to removably accommodate such an aerosol-forming article 20 with predominantly planar form factor, maximizing the heating efficiency and increasing the consumable extraction, without quickly depleting the aerosol. To do so, a full contact between the at least one heating element 6, 7 of the heating device 6a and the aerosolforming article 20 may be ensured during the heating phase or usage session. As will be shown below, substantially flat or planar heating elements 6, 7 may provide the benefit of keeping a high ratio of surface heated versus substrate volume, which, in turn, can provide for a faster and more homogeneous substrate heating.

[0348] The aerosol-forming article 20 may also comprise an airflow path through the frame 21 and the substrate 23 in the substrate chamber. A detailed view of the aerosol-forming article 20 is given in Figure 3. The aerosol-forming article 20 may be predominantly flat or planar. It may be shaped as a rectangular parallelepiped or cuboid. It may comprise the frame 21 or consumable frame 21 having a cavity 22 designed to accommodate the aerosol-forming substrate 23.

[0349] The aerosol-forming article 20 can have a substantially rectangular parallelepiped shape defining two opposing main faces 20a, 20b, which constitute the majority of the surface of thearticle 20. The aerosol-forming article 20 further defines two opposing side faces 20e, 20f or lateral faces 20e, 20f. The two opposing side faces or lateral faces 20e, 20f may extend parallel to a longitudinal direction of the aerosol-forming article 20. The aerosol-forming article 20 further defines or comprises two opposing smallest faces or surfaces 20c, 20d, which oppose each other in longitudinal direction of the aerosol-forming article 20.

[0350] On the sides or main faces 20a, 20b of the cavity 22, where no frame 21 may be located, the cavity 22 may be closed off from the outside environment by a sheet of cellulose fiber material, for example paper or rolling paper, or paper-like material. Such a sheet may be provided on both sides of the aerosol-forming article 20.

[0351] The frame 21 or article 20 may further comprise a consumable air inlet 24 arranged at one of the smallest faces 20c and an air or aerosol outlet 25 arranged at the opposite smallest face 20d, which may be arranged substantially in-axis with a direction of longitudinal extension of the aerosol-forming article 20 at the smallest faces 20c, 20d. Accordingly, the air inlet 24 and the aerosol outlet 25 can define a longitudinal direction or axis of the aerosol-forming article 20.

[0352] The air inlet 24 and the air outlet 25 may be arranged at the smallest opposing faces or surfaces 20c, 20d of the aerosol-forming article 2. The air inlet 24 and the air outlet 25 may be fluidically connected to a consumable air inlet channel 26 and a consumable air outlet channel 27, respectively. These channels 26, 27 may be configured to be in fluid communication with the consumable cavity 22.

[0353] The air inlet 24, the air inlet channel 26, the air outlet channel 27 and the air or aerosol outlet 25 each may have a cross-section shaped to correspond in surface area and ratio with the cross-section of the aerosol-forming article 20 and also the substrate 23. For example, the crosssection of the air inlet 24, the air inlet channel 26, the air outlet channel 27 and the air or aerosol outlet 25 is smaller than the cross-section of the aerosol-forming article 20, but the shape of the cross sections may be similar to each other. In other words, the air inlet 24, the air inlet channel 26, the air outlet channel 27 and the air outlet 25 may have a rectangular cross-section, optionally with rounded corners. Therefore, the cross-section may be in the shape of an oblong or ovally-shaped or oval-shaped hole. In this way, the air flowing through the airflow path provided by this cross-section may enter and stream through the similarly arranged substrate 23 in an optimal way. The cross-section as used herein may be perpendicular to a longitudinal axis of the aerosolforming article 20 and / or the direction of the airflow path through the aerosol-forming article 20.

[0354] An exemplary heating concept for the aerosol-forming article 20 as described above is shown in Figure 4 and subsequent Figures. The aerosol-forming device 1 can optionally comprise a heating module 34, as shown in Figure 4. The heating module 34, also referred to as heater module 34, may comprise at least part of or the entire heating device 6a. In particular, the heating module 34 may comprise the two opposing heating elements 6, 7 of the heating device 6a, forexample substantially flat or planar heating elements 6, 7, which may be arranged parallel and opposite to each other, for example in a sandwich configuration with the aerosol-forming article 20 between them.

[0355] An interior of or the entire heating module 34 may define the heating chamber 30. The space between the two heating elements in transverse direction of the device 1 can define the heating volume 30a, which can be a part or subspace of the heating chamber 30. The aerosolforming article 20 may be at least partially or fully inserted into the heating chamber 30 or heating volume 30a. Outer walls of the heating chamber 30 may be defined or provided by an optional heater casing 35, which may also contain the heating elements 6, 7. The heater casing 35 may be arranged in an insulating casing 2 to prevent heat from the heating elements 6, 7 from dissipating and / or reaching the user’s fingers, and for concentrating the heat to the heating chamber 30. The heating elements 6, 7 may be arranged parallel to the two main surfaces 20a, 20b of the aerosol-forming article 20 and define a heating volume therebetween to heat the aerosol-forming substrate 23. The heating elements 6, 7 may be arranged parallel to an inner surface of the heating chamber 30 and / or heater casing 35. The heating chamber 30 may be a substantially cuboid receptacle or space configured to at least partially receive the aerosolforming article 20. It may be defined by at least one side or two parallel, opposite sides configured as a planar cavity surface extending substantially in a plane. The heating element 6 and / or the heating element 7 may extend substantially in a plane parallel to the plane of the planar cavity surface.

[0356] A more detailed view of the heating chamber 30 and heating volume 30a and its arrangement in the aerosol-forming device 1 is shown in Figures 5 and 6. The heating chamber 30 may comprise the two heating elements 6, 7 of the heating device 6a. The two heating elements 6, 7 are also referred to herein as first heating element 6 and second heating element 7 of the heating device 6a. The heating elements 6, 7 are arranged in a parallel configuration and opposed to each other. In the specific embodiment shown, the two heating elements 6, 7 may be resistive or Joule-type heaters that transfer heat by heat conduction to the substrate 23 of the aerosol-forming article 20. However, other heating technologies or a combination of different heating technologies may be used.

[0357] The heating chamber 30 may further comprise an insulation casing 2 or insulating casing 2 which may act as an outer first insulation element and may provide an airgap for the airflow. The airgap may have a constant size or cross-section along its extension or may have sections differing in size or cross-section, as will be described with reference to Figure 10. The heating chamber 30 may further comprise the heater casing 35 which may be defined at least at one side by a planar cavity surface extending substantially in a plane and which may be configured to enclose the heating elements 6 and 7, wherein the heating elements 6, 7 may be further held inplace by a clamp element 8. The heater casing 35 may have a rectangular cross section and may be configured such to receive at least a portion of an aerosol-forming article 20 that is substantially planar (like the one shown in Figures 2 and 3) and to heat the aerosol-forming article 20 from the outside. In addition, an air space or the heating volume 30a may be provided between the heating elements 6,7 and the inner walls of the heating chamber 30, respectively, that may be thermally insulated.

[0358] The heater casing 35 and / or the heating chamber 30 may have walls with heat-reflecting properties. This may allow to reduce the thermal losses when resistively heating and concentrate the heat within the heating chamber 30 and heating volume 30a, and may also provide for an integrated mechanism for a user being able to firmly hold the aerosol-forming device 1 at a given place without being subjected to unsafe or unpleasant temperatures. The heater casing 35 may also be designed with grooves, channels or any generic means along inner walls of the heating chamber 30 to provide an air flow channel for the air flow through portions of the aerosol-forming device 1, for example a channel that is formed at the longer side faces of the rectangular parallelepiped shape heating chamber 30.

[0359] As shown in Figure 6, the heating elements 6, 7 of the heating device may be curved or convex towards or in direction of the two opposing main surfaces 20a, 20b of the aerosol-forming article. This can ensure good thermal contact. Further optionally, the heating elements 6, 7 may be formed as heating plates or may have a heating structure in the form of heating tracks, as shown in Figure 6. For instance, the heating elements can be substantially flat or planar, which however does not exclude that at least a part of the heating elements is curved or convex towards the substrate 23.

[0360] As further shown in Figure 6, the upstream heating device 70 can be configured as a convective heater assembly 70, which may be arranged upstream the aerosol-forming article 20, the heating chamber 30, the heating volume 30a and upstream the heating device 6a, respectively, the heating elements 6, 7 thereof, in order to heat the air entering the aerosolforming article 20.

[0361] Upstream heating device 70 may comprise at least one resistive heating element 71 or convective heater 71 which may be a resistive component which may transfer heat by convection to the surrounding air. The resistive heating element 71 may be arranged inside a convective heater casing 72 and may be held in place by a bottom cap 75.

[0362] As also shown in Figure 6, the heater casing 35 and / or the insulation casing 2 may be composed by two shells, for example an upper shell and a bottom shell, which may be designed to be engaged and / or combined during assembly. Heater casing 35 and / or insulation casing 2 may be made of a plastic material such as polyether ether ketone (PEEK) and / or polyaryletherketone (PAEK) and / or polyetherimide (PEI), preferably PEEK. Heater casing 35 canalso have thermal insulation properties like insulating casing 2, for example having a high thermal resistivity or low thermal conductivity, preferably a thermal conductivity below 1 W / (m • K), more preferably below 0.5 W / (m • K).

[0363] It is also possible that the entire heating module 34 comprising the heating chamber 30 may be removably placed inside the body 800 or device body 800 of the aerosol-forming device 1, for example with electric connection terminals that may be arranged to be in parallel with the main axis of extension or the longitudinal axis of the aerosol-forming device 1, and which can interconnect to corresponding terminals inside the body 800 of device 1. The longitudinal axis of the device 1 may be the same as and / or parallel to the insertion axis or the insertion direction of the aerosol-forming article 20 into the heating chamber 30. The connection may be formed only by the movement of the heating chamber 30 when being inserted into the device body 800.

[0364] As indicated in Figure 5, the aerosol-forming device 1 can include a device body 800 or body 800 and a downstream element 802. The downstream element 802 can also be referred as second housing part or mouthpiece portion 802. Optionally, the mouthpiece 901 may be arranged at the downstream element 802.

[0365] The downstream element 802 may be movably attached to the device body 800, such that the device body 800 and the downstream element 802 can be movable relative to each other between an open position and a use position. In the open position access to the heating chamber 30 and / or heating volume 30a can be provided, such that the aerosol-forming article 20 is removable from or insertable into the heating chamber 30 and / or heating volume 30a. In the closed position, as shown in Figure 5, the heating chamber 30 and / or heating volume 30a is closed and cannot be accessed by the user. Also the heater module 34 may be removed from or inserted into the device body 800 in the open position.

[0366] The downstream element 802 and the device body 800 can be coupled to each other via an interconnection mechanism 802 arranged between the downstream element 802 and the device body 800, and permitting the movement between the open and the use position. Therein, the movement can include a rotational movement, a linear movement, or combination of a rotational and linear movement.

[0367] Figure 7 shows a cross-sectional view of a heater module 34 and a upstream heating device 70 for an aerosol-forming device 1. The top depiction of Figure 7 shows a top view of the section of the device 1 comprising the heating chamber 30.

[0368] With reference to Figure 7, the heating chamber 30 may be associated with the upstream heating device 70 or convective heater assembly 70, for example to boost the extraction of the aerosol compounds from the aerosol-forming article 20. The bottom depiction of the Figure shows a lateral or side view of the upstream heating device 70.The upstream heating device 70 may contribute to the definition of the upstream airflow path 40a and may be arranged upstream the heating chamber 30 and / or heating volume 30a to guarantee a continuous route for the airflow through the aerosol-forming device 1. The air may therefore enter the convective heating assembly 70, be heated, and then enter the heating chamber 30 and / or heating volume 30a with the aerosol-forming article 20. Preferably, the convective heater assembly 70 or upstream heating device 70 is arranged such that an airflow path from the resistive heating element 71 to the upstream inlet 24 of article 24 is as short as possible, to avoid a drop of temperature to the air after passing the resistive heating element 71. In a variant, it is also possible that the resistive heating element 71 protrudes into the upstream air inlet 24 of the article 20, when the article 20 is in an inserted position.

[0369] The upstream heating device 70 may include the resistive heating element 71 and a convective heater casing 72, wherein the convective heater casing 72 may have a convective heating chamber 73 configured to receive the resistive heating element 71, without getting in direct contact with inner walls of the convective heating chamber 73. This configuration may define two gaps 74 above and below the heating element 71 (best visible in the lateral cross-sectional view of the bottom of Figure 7) which allows a convective heat exchange between the resistive heating element 71 and the surrounding air passing through the gaps 74. In other words, the gaps 74 may form a part of the airflow channel through the aerosol-forming device 1 leading through the upstream heating device 70.

[0370] The resistive heating element 71 of the upstream heating device 70 can be formed as a meandering or serpentine structure, extending in-plane of the resistive heating element 71. Alternatively or additionally, the resistive heating element 71 can comprise at least one strip of a metal sheet, optionally wherein the strip of metal sheet is perforated and / or includes one or more perforation openings or holes. Alternatively or additionally, the resistive heating element 71 can comprise at least one strip of a metal sheet, the at least one strip being bent or formed into a stack of a plurality of serpentine-like formed branches, preferably the branches of the stack spanning between two terminals of the resistive heating element 71.

[0371] Further, a bottom cap 75 can ensure that the upstream heating device 70 and the heating chamber 30 are held together. Preferably, the convective heater casing 72 is made of a material that has low thermal conductivity, so that a heating of the inner walls of the heater casing 72 is reduced, with the goal to provide the heating energy preferentially or predominantly to the incoming air. For example, preferably, the heater casing 72 is not made of metal, but of a thermoplastic with high temperature resistivity and low thermal conductivity, preferably PEEK or PEI.

[0372] The dimensions of the cavity or heating volume 30a provided by the heating chamber 30 may reflect the dimensions of the aerosol-forming article 20 in order to ensure that the article 20can be inserted to the heating chamber 30 or volume 30a and arranged between heating elements 6,7, although a part of the aerosol-forming article 20 may protrude out of the heating chamber 30 and heating volume 30a. Preferably, the fit should be a light press-fit or a light interference fit with the aerosol-forming article 20 between heating elements 6, 7. For example, the heating chamber 30 and / or heating volume 30a may have a length L3 of from 10 mm to 35 mm, for example of from 15 mm to 30 mm or from 15 mm to 25 mm. This may also be referred to as the insertion depth of the heating chamber 30 and / or heating volume 30a. The heating chamber 30 and / or heating volume 30a may have a width W3 of between 7.2 mm and 15.2 mm, preferably between 9.2 mm and 13.2 mm, more preferably about 11.2 mm. The heating chamber 30 and / or heating volume 30a may have a thickness T3 of between 2 mm and 10 mm, more preferably between 3 mm and 8 mm, even more preferably between 4 mm and 6 mm. These values may pertain to the inside clearances of the heating chamber 30 and / or heating volume 30a in the respective directions. Again, these values are purely exemplary, and any other suitable dimensions may be chosen.

[0373] A benefit of using substantially flat or planar heating elements 6, 7, which can include slightly curved or convex shapes, for the heating device 6a as described may be the provision of a faster and more homogeneous substrate heating. This may be achieved by the high ratio of surface heated to substrate volume. To further improve aerosol extraction from the aerosol-forming article 20, the contact pressure between the aerosol-forming article 20 and the heating element 6, 7 may be increased.

[0374] According to at least some aspects of the present disclosure, heating elements 6, 7 can be provided, that allow to firmly contact a to-be-heated surface of the aerosol-forming article 20 for example at a location where the substrate 23 is located inside the article 20. The heating elements 6, 7 can be resistive or Joule-type heater elements, but other types of heating are also possible, for example inductive heating with elements 6, 7 acting as susceptors. In addition, an air space may be provided around the heating elements 6, 7 to thermally insulate the heating chamber 30 and the heater casing 35.

[0375] Figure 6 also schematically shows a fluidic interconnection element 88, which is also referred to as upstream fluidic interconnection element 88. The fluidic interconnection element 88 may be configured to provide for a fluidic connection between the air inlet 24 of the article 20 and the upstream airflow path 40a. A further or downstream fluidic interconnection element may connect the aerosol outlet 26 of the article 20 to the downstream element 802 or an airflow path therein.

[0376] The fluidic interconnection element 88 can have a blade or blade structure, which may surround the upstream airflow path 40a. The blade may define an opening of the fluidic interconnection element 88 through which the airflow path 40a can be arranged. The openingmay have an oblong shape, for example in cross-section, for example perpendicular to the air flow direction

[0377] The blade structure may be tapered on both the inside and the outside surface of the fluidic interconnection element 88, i.e. both the inside surface contacting the air in the airflow path or channel and the surface directed away from the airflow path or channel. Alternatively, the blade structure may be tapered only or exclusively on the outside surface of the fluidic interconnection element 88. By only tapering the outside surface of the fluidic interconnection element 88 and leaving the inside surfaces completely flat and smooth, the airflow in the airflow path or channel may not be influenced in any way. A tapered inside surface may, otherwise, act as a flow restriction, possibly negatively affecting the airflow. Additionally, by leaving the inside surface of the fluidic interconnection element 88 straight and only tapering the outside surface, when the fluidic interconnection element 88 is inserted into the frame 21 of the aerosol-forming article 20 by penetration, the material of the frame 21 may be only or substantially only displaced by the tapered outside surface, displacing the material in a direction away from the airflow path 40a or channel. In this way, no displaced material of the frame 21 is displaced or otherwise pressured into the airflow path or channel, which would again possibly affect the airflow negatively and impact aerosol formation. This can be avoided by the specific shape of the hollow blade structure as explained herein.

[0378] Figure 8 shows several cross-sections through an aerosol-forming device 1, and illustrates an exemplary airflow through the aerosol-forming device 1. The top of Figure 8 shows a crosssection through heating chamber 30 or module arranged in the aerosol-forming device 1, and the middle and bottom sections of Figure 8 show a cross-section primarily through the heating module 34. It is noted that the airflow path shown and described with reference to Figure 8 is exemplary only. Many variations are possible.

[0379] Via one or more air inlets 46, device inlets 46 or main air inlets 46, air can enter the body 800, downstream element 802 and / or housing of the aerosol-forming device 1. The exemplary airflow path through the aerosol-forming device 1 of Figure 8 may begin with a first airflow path portion 40 beginning at the air inlet 46. The device air inlet 46 may comprise a peripheral gap between the mouthpiece portion 900 and the device body 800. The peripheral gap may be continuous around the entire device 1, or may have several, potentially separate, sections or portions or openings around the device body 800. In another variant, there is one gap on each side between downstream element 802 and device body 800.

[0380] The gap forming the device air inlet 46 may have a diameter or clearance of at most 0.05 mm or at most 0.075 mm or at most 0.1 mm or at most 0.125 mm or at most 0.15 mm or at most 0.175 mm or at most 0.2 mm. The gap or clearance may be provided around a portion of the perimeter or the circumference of the aerosol-forming device 1, the portion for example being atleast 50 % or at least 75 % or at least 90 % of the perimeter or the circumference. Alternatively, the device air inlet 46 may be configured as one or more lateral holes or channels. The lateral holes may be placed at the interface of an outer surface of the downstream element 802 and the device body 800. This placement of the device air inlets 46 may present several advantages, as it may allow for easy cleaning of the airflow path to remove obstructions when the mouthpiece 901 is removed, and it may allow to conceal or make the inlets less visible. Finally, obstruction by the hand and / or fingers of the user may be made less likely. That the device air inlet 46 may be hidden may also enhance design aspects, e.g., the device air inlet 46 may be arranged inside a groove, behind a hinge, or behind a snap, or the like.

[0381] The airflow path may proceed in a second airflow path portion 41 , which may be provided by a gap between the insulation casing 2 and the heater casing 35, or through a channel inside the heater casing 35 itself. The insulating casing 2 and the heater casing 35 may have a rectangular parallelepiped shape. This makes several suitable airflow paths possible between these two elements. For example, there may be two parallel flow path portions on two opposite sides of the aerosol-forming article 20. In these, the air may flow parallel to an axis of longitudinal extension of the aerosol-forming article 20 along the larger side surfaces, or there may be two parallel flow path portions at the two smaller side surfaces of the aerosol-forming article 20 or consumable. In the latter option, the air may flow parallel to the axis of longitudinal extension of the aerosol-forming article 20 along the smaller lateral sides. Also, a combination of these flow paths may be used. With the two parallel flow path portions 41 on the smaller side surfaces 20e, 2 Of , and the heater elements 6, 7 arranged to face the larger side surfaces 20a, 20b of the aerosolforming article 20, it is possible to separate a heating of the substrate 23 and a heating of the incoming airflow, such that the air heating is mainly performed by the upstream heating device 70, and not by the heater elements 6, 7. In case the upstream heating device 70 is operated on a puff-basis, e.g. is only heated when a puff occurs, this separation of these heating aspects allows to save energy and better control a temperature of the heat departed to the airflow by the upstream heating device 70.

[0382] Once the airflow reaches the bottom or distal end part of the insulation casing 2, which may mean the part of the insulating casing 2 opposite the mouthpiece 901 , it may then be redirected towards the upstream heating device 70 that may accommodate the resistive heating element 71. For this, there may be provided a further airflow path portion 48 which leads the air radially or laterally inwards towards the longitudinal central axis of the aerosol-forming device 1. The airflow path from the entry into the upstream heating device 70 parallel to the longitudinal axis of the device 1 onwards may constitute the upstream airflow path 40a, as described herein, which is exemplary shown as third airflow path portion 42 in Figure 8.The air may enter the upstream heating device 70 and pass along the resistive heating element 71. In one variant, the airflow may change direction from a direction parallel to the longitudinal axis of the aerosol-forming device 1 by approximately 90° to progress towards a center axis or longitudinal axis of the aerosol-forming device 1, and then may change direction again by 90° to pass through the upstream heating device 70 which may be arranged in parallel with the longitudinal axis of the aerosol-forming device 1. Therefore, the airflow may change flow direction by 180° or make a U-turn between the second airflow path portion 41 and third airflow path portion 42. This U-turn may be the further airflow path portion 48. In another variant, the resistive heating element 71 may be arranged orthogonal to the longitudinal axis of the aerosolforming device 1, and the airflow may pass through the resistive heating element 71 while progressing towards the center axis or longitudinal axis of the aerosol-forming device 1. In this case, the upstream heating device 70 may be part of or arranged in the further airflow path portion 48. The airflow may then change direction again by 90° to leave the resistive heating element 71 and / or the upstream heating device 70 to directly enter the aerosol-forming article 20 through air inlet 24, optionally via the upstream fluidic interconnection element 88. The third airflow path portion 42 may then shorten. Two parallel airflow path portions 41 can be fluidically reunited, for example merged or combined, at element or portion 42. This allows for redundancy if one of them is blocked. The parallel arrangement reduces the overall resistance-to-draw.

[0383] The passage of the air through the resistive heating element 71 and / or the upstream heating device 70 may be particularly relevant because it may allow the air coming from the outside environment and having ambient temperature (passing through airflow path portions 40 and 41) to be heated by the resistive heating element 71 in very close proximity before arriving at the substrate 23. The bottom and / or distal end part of the insulating casing 2, which is directed away from the mouthpiece 901 or inhalation side of the device 1, may be referred to as the convective heating chamber 73, and may be configured with a convective or heat exchange heater placed therein to heat up the air upstream of the article 20. Different configurations of the upstream heating device 70 and resistive heating element 71 are possible. In general, it may be desirable to use a resistive heating element 71 with a heating surface as large as possible, so that a large air surface may come into contact with the heated surfaces of the resistive heating element 71.

[0384] To actually control the energy storage 15 or power source 15, the heating device 6a, the heating elements 6, 7 and optionally the upstream heating device 70, the aerosol-forming device 1 may store one or more heating profiles 200 for the heating device 6a and optionally one or more heating profiles 300 for the upstream heating device 70, for example in a data storage 11 or memory 11 of the aerosol-forming device 1.Exemplary heating profiles 200 for the heating device 6a are shown in Figures 9, 10 and 11, and exemplary heating profiles 300 for the upstream heating device 70 are shown in Figures 12 and 13.

[0385] It is noted that Figures 9 to 13 illustrate exemplary temperature profiles 200, 300, wherein Figures 9 to 13 particularly show measured temperatures of the heating device 6a and the upstream heating device 70a. More specifically, the temperature values shown in Figures 9 to 11 may correspond to measured temperature values of the heating elements 6, 7 of the heating device 6a. These temperature values can be average temperature values of the surfaces of the heating elements 6, 7, which contact the aerosol-forming substrate 23 or article 20. Likewise, the temperature values shown as curve 302 in Figures 12 to 13 may correspond to measured temperature values of the upstream heating device 70 and / or its resistive heating element 71. The actual heating profile 300 may rather be represented by the dashed curve 304 in Figures 12 and 13. These temperature values can be average temperature values of the surface of the resistive heating element 71 that is exposed to air. As can be seen in Figures 9 to 13, the measured temperature values fluctuate around the course of the temperature defined in the respective heating profiles 200, 300. Hence, the measured temperature values shown in Figures 9 to 13 illustrate the heating profiles 200, 300 and the one or more target temperatures defined therein. It should further be noted that the fluctuations in the temperature profiles 300 of the upstream heating device 70 shown in Figures 12 to 13 occurring between the puffs or user inhalations result from measurement only and do not represent the actual heating profile 300 of the upstream heating device 70. As explained in detail herein, the upstream heating device 70 may be deactivated between puffs or user inhalations, or may at least be powered at the first power level, respectively, a comparatively low power level.

[0386] Generally, each heating profile 200, 300 may define one or more temperatures or temperature values, optionally each temperature associated with a particular time from the start of the usage session. For example, the temperatures indicated or defined by the heating profile may be in the range from 125°C to 350°C.

[0387] Generally, each of the heating profiles 200, 300 may be configured to instruct, or may be considered as instructions for, the control circuitry 5 to heat the heating elements 6, 7 of the heating device 6a and / or the upstream heating device 70, such that the one or more temperatures are reached substantially at the associated time from the start of the usage session.

[0388] Figure 9 illustrates an exemplary heating profile 200 for the heating device 6a of the aerosolforming device 1. As noted above, the heating device 6a can be configured to heat the substrate 23 in a continuous heating operation during a usage session.

[0389] The heating profile 200 is illustrated in Figure 9 in the form of a curve 202 of a temperature (in °C) of the heating device 6a and / or the heating elements 6, 7 thereof versus time (in seconds)during a usage session. However, the heating profile 200 may alternatively or additionally be defined in terms of one or more other parameters indicative of or correlated with the temperature of the heating device 6a and / or its heating elements 6, 7, such as the electrical resistance of the heating device 6a.

[0390] The heating profile 200 defines a plurality of target temperature that the heating elements 6, 7 should preferably both be heated to, for example simultaneously or synchronously, based on corresponding control by the control circuitry 5. Accordingly, the control circuitry 5 may be configured to operate the heating device 6a and the heating elements 6, 7, such that at least a part of the heating device 6a reaches the one or more temperatures as defined for the respective moment or time during the usage session, for example from start of the usage session.

[0391] The exemplary heating profile 200 shown in Figure 9 has a maximum duration of about 500 seconds (around 8 minutes), and a maximum heating temperature of about 280 to 290 °C. Generally, the maximum duration may vary between 3 minutes and 12 minutes, and the target temperatures defined by the heating profile 200 may be in the range of about 200°C to about 300°C. The heating profile 200 of Figure 9 may correspond to a comparatively long usage session with a comparatively low average temperature of the heating elements 6, 7 across the usage session, when compared to the shorter heating profiles 200 or the heating profiles 200 defining shorter maximum durations shown in Figures 10 and 11.

[0392] When the aerosol-forming device 1 is started or activated by the user for aerosol consumption, the control circuitry 5 can be configured to operate or power the heating device 6a according to the heating profile 200. Accordingly, the heating profile 200 for the heating device 6a, and optionally the heating profile 300 for the upstream heating device 70, may be started upon activation of the device 1 by the user for aerosol-consumption. The actual usage session, where user may inhale aerosol in one or more user inhalations, may start after a predetermined period of time or heat-up phase after activation of the aerosol-forming device 1 by the user for aerosol consumption, respectively after start of the heating profile 200. The predetermined period of time for the heat-up phase may be between about 5 seconds and about 35 seconds, for example about 20 seconds. Alternatively or additionally, a usage session may start upon reaching a predetermined temperature, for example a temperature close to, corresponding to or above the volatilization temperature of the substrate 23. Accordingly, the heating device 6a and optionally the upstream heating device 70 may be powered or operated by the control circuitry 5 upon activation of the device 1 by the user according to one or more heating profiles 200, 300, and the usage session where the user takes one or more user inhalations may start afterwards, for example after expiry of the predetermined time and / or after reaching a predetermined temperature. Hence, the temperature profile 200 may show a timely evolution of the temperature of the heating device 6a and / or its heating elements 6, 7, for example starting at 0 seconds inFigures 9 to 13, where the heating device 6a may begin to heat, while the usage session may only start once a predetermined temperature of the substrate 23 has been reached and / or a predetermined period of time has expired or elapsed.

[0393] When the aerosol-forming device 1 is started or activated by the user for aerosol consumption, the control circuitry 5 can be configured to rapidly increase the temperature of the heating device 6a, during a first phase 204 of the usage session from an initial temperature to a first target temperature of the first phase 204. The initial temperature may substantially correspond to the room or ambient temperature. The first phase may primarily serve to boost the temperature of the heating elements 6, 7, which may contact the aerosol-forming article 20 from two the two opposing main faces 20a, 20b, thereby rapidly increasing the temperature of the substrate 23. Also, moisture and other liquid constituents of the substrate 23 may be vaporized during the first phase 204, which may be beneficial in terms of taste, reduction of hot-aerosol effect, and lead to a more homogenous aerosol consumption for the user during the usage session.

[0394] In the example shown in Figure 9, the first target temperature may be about 285°C, which may also correspond to the maximum temperature of the usage session as defined by the respective heating profile 200. Generally, however, as shown in Figures 9 to 11, the first target temperature may be in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.

[0395] The control circuitry 5 is configured to increase the temperature of the heating elements 6, 7 from the initial temperature to the first target temperature at the beginning of the usage session at 0 seconds preferably as fast as possible, for example by supplying maximum power to the heating elements 6, 7. For the example, the temperature of the heating elements 6, 7 may rise within less than 10 seconds to more than 200°C.

[0396] Generally, however, as shown in Figures 9 to 11, a temperature rise in the first phase 204 or at least at the beginning of the first phase 204 may be about 200°C within about 1 to 20 seconds, for example about 200°C within 2 to 15 seconds, preferably about 200°C within about 5 to 10 seconds. Towards reaching the first target temperature of the first phase 204, for example when heating to temperatures above about 150°C to about 220°C, the temperature rise or increase may slow down, for example to a temperature rise of about 100°C within about 20 to 30 seconds, for example about 100°C within 20 seconds, preferably about 100°C within 5 to 15 seconds. For instance reaching the first target temperature of the first phase 204, the temperature rise may be about 80°C within 10 to 15 seconds.

[0397] Upon reaching the first target temperature, for example at about 18 seconds to about 22 seconds, the control circuitry 5 can be configured to maintain the first target temperature for therest of the first phase 204 of the usage session. A duration of the first phase in the example of Figure 9 is about 30 seconds to about 40 seconds. Generally, however, as shown in Figures 9 to 11, the duration of the first phase 204 of the usage session may be between about 2 seconds and about 75 seconds, for example between about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 35 seconds.

[0398] The first target temperature may be above a volatilization temperature. The volatilization temperature may also be referred to as vaporization temperature and may denote a temperature sufficient to vaporize one or more ingredients from the substrate 23. Accordingly, at least upon reaching the first target temperature in the first phase 204 at about 18 to 22 seconds after start of the usage session, inhalable aerosol can be generated.

[0399] Optionally, the control circuitry 5 can be configured to signal to the user when the device 1 is ready for aerosol consumption. For example, a fixed predetermined period of time for a heatup phase from the start of a usage session may be defined in the device 1 or heating profile 200. Upon reaching this predetermined period of time, the control circuitry may actuate one or more user interface components 18 or output elements 18, thereby signaling to the user that they can start inhaling aerosol in one or more user inhalations. The predetermined period of time for the heat-up phase may be between about 5 seconds and about 35 seconds, for example about 20 seconds. Alternatively or additionally, the control circuitry 5 may indicate to the user when the first target temperature is reached, which may optionally mark the start of the actual user inhalations.

[0400] The control circuitry 5 may be configured to maintain the first target temperature for about 5 seconds to about 30 seconds, for example about 7 seconds to about 15 seconds.

[0401] Further, the control circuitry 5 can be configured to decrease the temperature of the heating elements 6, 7 from the first target temperature to a second target temperature in a second phase 206 of the usage session. The descend or decrease in temperature in the second phase 206 can allow the temperature gradients generated in the substrate 23 in the first phase 204 to propagate through the substrate volume 23, thereby leading to a more uniform heat distribution across the substrate volume, which can lead to a well-defined and homogenous aerosol consumption through the rest of the usage session.

[0402] In the example shown in Figure 9, the second target temperature is about 220°C. Generally, however, as shown in Figures 9 to 11, the second target temperature of the second phase 206 can be in a range from about 200°C to about 290°C, in particular from about 210°C to about 280°C, for example from about 220°C to about 270°C, preferably from about 220°C to about 250°C.

[0403] The duration of the second phase 206 in the example of Figure 9 is about 10 seconds to about 20 seconds. Generally, however, as shown in Figures 9 to 11 , the duration of the second phase 206 may be between about between about 2 seconds and about 100 seconds, for examplebetween about 5 seconds and about 50 seconds, preferably between about 10 seconds and about 30 seconds.

[0404] An exemplary temperature drop or decrease in the second phase 206 from the first target temperature to the second target temperature may be about 10°C within about 1 to 25 seconds, for example about 10°C within 2 to 10 seconds, in particular about 10°C within about 5 to 10 seconds. Such exemplary temperature drops are shown in Figures 9 to 11. In particular, in the example of Figure 9, the temperature drop in the second phase 206 is about 60°C within about 20 to 25 seconds, whereas a temperature drop of about 60°C within about 50 seconds is shown in Figure 10 and a drop of about 40°C within 25 seconds is shown in Figure 11.

[0405] The control circuitry 5 can be configured to increase the temperature of the heating elements 6, 7 upon reaching the second target temperature to a third target temperature in a third phase 208 of the usage session. In the example of Figure 9, the third target temperature is about 285°C and corresponds to the first target temperature. Also, the third target temperature is reached towards or at the end of the usage session or third phase 208 of the usage session, such that the temperature is gradually increased in the third phase 208 from the second target temperature to the third target temperature. The gradual increase in temperature may compensate for the progressing depletion with progressing time from the start of the usage session.

[0406] Generally, the third target temperature of the third phase 208 can be in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.

[0407] The third phase 208 may refer to the majority of time of the usage session, and the user may inhale aerosol throughout the third phase 208 in one or more user inhalations. In the example of Figure 9, the duration of third phase 208 is about 450 seconds. Generally, however, as shown in Figures 9 to 11, the duration of the third phase 208 may be between about 50 seconds and about 800 seconds, for example between about 150 seconds and about 600 seconds, preferably between about 200 seconds and about 450 seconds.

[0408] Upon reaching the third target temperature and a maximum duration of the usage session, which may also be defined in the heating profile 200, the control circuitry 5 may deactivate the energy storage 15 and / or a power supply to the heating elements 6, 7, thereby terminating the usage session.

[0409] As shown in the exemplary heating profiles 200 of Figures 9 to 11 , a temperature rise or increase in the third phase 208 from the second target temperature to the third target temperature may be about 10°C within about 10 to 120 seconds, for example about 10°C within 15 to 100 seconds, in particular about 10°C within about 20 to 50 seconds. Such exemplary temperature increases are shown in Figures 9 to 11. In particular, in the example of Figure 9, the temperatureincrease in the third phase 208 is about 60°C within about 450 seconds, whereas a temperature increase of about 30°C within about 275 seconds is shown in Figure 10 and an increase of about 40°C within 75 seconds is shown in Figure 11.

[0410] It should be noted that the control circuitry 5 may be configured to switch between the subsequent phases of the usage session based on temperature, based on time or both. For instance, the control circuitry 5 can be configured to maintain the first target temperature in the first phase 204 for a predetermined period of time and switch to the second phase 206 upon reaching this time. Alternatively or additionally, the control circuitry 5 may be configured to switch to the third phase 206 upon reaching the second target temperature or optionally maintain the second target temperature for a predetermined period of time. Any combination of time and temperature-based control to switch or change between subsequent phases 204, 206, 208 of a usage session can be implemented.

[0411] Also, it should be noted that for each phase at least one target temperature and optionally at least one time from start of the usage session or respective phase of the usage session, at which the target temperature should be reached can be defined in the heating profile 200. The control circuitry 5 can be configured to heat the heating elements 6, 7 gradually or step-wise from an initial temperature at the start of each phase 204, 206, 208 to the target temperature of the respective phase 204, 206, 208. For this purpose, the control circuitry 5 may apply a function or formula to smoothly increase or decrease the temperature. Alternatively, one or more intermediate temperature values and optionally one or more intermediate times since start of the usage session or the respective phase 204, 206, 208 may be defined in the heating profile 200, which can enable the control circuitry 5 to smoothly or gradually change the temperature of the heating elements 6, 7, according to the heating profile.

[0412] The control circuitry 5 may also be configured to apply one of the plurality of heating profiles 200 based on a user input at a user interface 18 or input device 19 of the aerosol-forming device 1. For example, the control circuitry 5 may be configured to select one of the plurality of heating profiles 200, as shown in Figures 9 to 11, based on the user input. Therein, the user input may be indicative of the user’s preference in terms of length or intensity of the aerosol experience, which may optionally be selected by the user on the user interface 18 or input device 19. Accordingly, the user may select its preferred experience or type of experience, and the control circuitry 5 may select the corresponding or associated heating profile 200. Alternatively or additionally, the user input may be indicative of a type of aerosol-forming article 20 to be used in the current usage session. For example, the user may select one type among a plurality of types of aerosol-forming articles 20 at the user interface 18 or input device 19, and the control circuitry 5 may select the corresponding heating profile 200.Selecting of a heating profile 200 by the control circuitry 5 can optionally include one or more of loading the selected heating profile 200, accessing data associated with the selected heating profile 200 at a data storage 11 of the aerosol-forming device 1 or an external data storage, and retrieving the selected heating profile 200 or data associated therewith from a smartphone or server communicatively couplable with the aerosol-forming device 1. The same applies to the one or more heating profiles 300 of the upstream heating device 70.

[0413] Alternatively or additionally, selecting of a heating profile 200 by the control circuitry 5 can optionally include enabling the selected heating profile 200 at the aerosol-forming device 1, loading settings associated with the selected heating profile 200, and operating the heating device 6a and / or heating elements 6, 7 in accordance or correspondence with the selected heating profile 200.

[0414] The control circuitry 5 can optionally be configured to apply and / or select one of the plurality of heating profiles 200 based on a type of the aerosol-forming article 20. Accordingly, the aerosolforming device 1 can be configured to automatically select a heating profile 200 based on the type of aerosol-forming article 20 used. This can allow for a seamless adaption of the heating of the aerosol-forming device 1 without requiring user selection or interaction, for example via user interface 19. Hence, user experience can be improved.

[0415] The aerosol-forming device 1 can, for example, comprise at least one sensor for determining a type of the aerosol-forming article 20, wherein the control circuitry 5 can be configured to apply and / or select one of the plurality of heating profiles 200 based on determining the type of aerosol-forming article 20 by means of the at least one sensor. In an example, the at least one sensor may be configured to detect or determine one or more indicia on the aerosolforming article 20 to determine the type of the article 20. For instance, a code, barcode, QR code, visible code, invisible code, taggant code, RFID tag or the like may be comprised by the aerosolforming article 20. The at least one sensor may be configured to read the code, barcode, QR code, visible code, invisible code, taggant code, RFID tag, and provide a corresponding signal to the control circuitry 5. The control circuitry 5, or optionally the sensor itself, can then determine the type of the aerosol-forming article 20, such that the control circuitry 5 can select the heating profile 200 associated with the respect type of aerosol-forming article 20. Other means to identify the aerosol-forming article 20 can be used.

[0416] The heating profiles 200 shown in any of Figures 9 to 11 may be specifically tailored to the design and configuration of the two opposing heating elements 6, 7 contacting the main faces 20a, 20c of the rectangular parallelepiped shaped aerosol-forming article 20, for example as shown in Figures 2 and 3.

[0417] In particular, the first phase 204 can correspond to an initial boost in temperature to release moisture and liquid constituents from the substrate 23 and pre-heat the substrate 23 to atemperature above the volatilization temperature, sufficient to release one or more ingredients from the substrate 23. The descend or decrease in temperature of the second phase 206 can allow for the temperature gradient generated during the first phase 204 to propagate through the substrate 23 and form a substantially or more uniform heat distribution across the substrate volume. Also, the decrease in temperature may allow to adjust an amount or volume of aerosol released per unit time from the substrate 23, which can be referred to as tuning of the released aerosol. In the third phase 208, the temperature can be gradually increased or ramped up to the third target temperature, which may allow to compensate for an increasing depletion of the substrate. Overall, an optimal user experience can be provided by this heating approach.

[0418] Figures 10 and 11 each illustrate a further exemplary heating profile 200 for the heating elements 6, 7 and / or the heating device 6a. Similar to Figure 9, Figures 10 and 11 each show measured temperature values around the target temperatures defined in the heating profile 200 for the heating device 6a of the aerosol-forming device 1 in the form of a curve 202 of a temperature (in °C) of the heating device 6a and / or the heating elements 6, 7 thereof versus time (in seconds) during a usage session. Any disclosure presented hereinabove with respect to the heating profile 200 of Figure 9, equally applies to the heating profiles 200 of any of Figures 10 and 11. In the following, primarily the difference between the heating profiles 200 of Figures 9, 10 and 11 are discussed.

[0419] The heating profile 200 of Figure 10 is rather similar in shape compared to the heating profile 200 of Figure 9. A maximum duration of the usage session as defined by profile 200 of Figure 10 is about 375 seconds, which is shorter than the maximum duration of a usage session defined by the heating profile 200 of Figure 9.

[0420] Further, the first target temperature defined by the heating profile 200 of Figure 10 is about 285 °C, which corresponds to the first target temperature of the heating profile 200 of Figure 9. Also the duration of the first phases 204 is very similar or identical.

[0421] However, the second target temperature that is reached at the end of the second phase 206 is about 240°C and is higher in the example shown in Figure 10 compared to the example of Figure 9. This may mean that the temperature is less lowered in the second phase 206 of the usage session in the heating profile 200 of Figure 10 that has a shorter maximum duration of the usage session defined.

[0422] As a consequence, the temperature of the heating element 6, 7 at the start of the third phase 208, where the temperature is ramped up to the third target temperature, is higher in the example of Figure 10 compared to Figure 9. The third target temperature of Figure 10 corresponds to the third target temperature shown in Figure 9. Overall, this leads to a higher average temperature of the heating elements 6, 7, throughout the usage session for the heating profile 200 shown in Figure 10 compared to that of Figure 9.Accordingly, the shorter maximum duration of the usage session defined by the heating profile 200 of Figure 10 can be compensated by a higher average temperature of the heating elements 6, 7 throughout the usage session. This way, a similar or substantially identical amounts or volumes of aerosol may be released when applying the heating profiles 200 of any of Figures 9 and 10, however within different maximum durations of the usage session. Accordingly, the same amount of aerosol can be inhaled within a shorter period of time when applying the heating profile 200 of Figure 10 when compared to applying the heating profile 200 of Figure 9. Hence, the aerosol experience may be more intense in the example of Figure 10.

[0423] Generally, a plurality of heating profiles 200 can be defined which may differ in maximum duration of the usage session and average temperature during the usage session, and optionally one or more other aspects, such as for example a maximum temperature reached in the usage session, a maximum or average temperature reached in one or more phases 204, 206, 208 of the usage session, or a duration of one or more phases. 204, 206, 208. For example, a long, medium and short heating profile 200 having a long, medium and short duration of the usage session defined therein can be stored at the aerosol-forming device 1. Optionally more or less heating profiles differing in maximum duration of the usage session may be stored.

[0424] Therein, the longer the maximum duration of a usage session associated with one of the heating profiles 200 can be, the lower can be the average temperature of the heating elements 6, 7 during the respective usage session. Alternatively or additionally, the shorter the maximum duration of a usage session associated with one of the heating profiles 200 can be, the higher can be the average temperature of the heating elements 6, 7 during the respective usage session. Hence, a shorter duration of the usage session can be compensated with a higher average temperature, and vice versa.

[0425] Figure 11 illustrates a further exemplary heating profile 200 which can be applied by the control circuitry 5 to heat the heating elements 6, 7. The heating profile 200 shown in Figure 11 defines a maximum duration of the usage session of about 200 seconds, and hence defines shorter usage sessions than the heating profiles of Figures 9 and 10.

[0426] Also, the temperature of the heating elements 6, 7 is higher in the example of Figure 11 compared to Figures 9 and 10. Accordingly, Figure 11 depicts a heating profile 200 defining a short maximum duration for the usage session and having a high average temperature throughout the usage session. Hence, the heating profile 200 may correspond to an intense aerosol experience.

[0427] While the first target temperature and the duration of the first phase 204 of the heating profile 200 of Figure 11 is similar or identical to the examples of Figures 9 and 10, the second target temperature is about 260°C. In addition, the third target temperature in the example of Figure 11 is about 300°C and thus higher than in the examples shown in Figures 9 and 10.Moreover, the duration of the third phase 208 of the example of Figure 11 is about 75 seconds, which is much shorter than the duration of the third phases 206 of the heating profiles 200 of Figures 9 and 10. Accordingly, the temperature is kept at a higher value in the second phase 206 and then ramped up to a higher temperature within shorter time in the third phase 208. This can lead to an intense aerosol experience.

[0428] In the example of Figure 11, the third phase 208 does not mark the end of the usage session, but the usage session or heating profile 200 defines a fourth phase 210, in which the third target temperature is maintained for the rest of the usage session or until the end of the usage session. Accordingly, the control circuitry 5 may be configured to, upon reaching the third target temperature, maintain the third target temperature in the fourth phase 210 of the usage session.

[0429] A duration of the fourth phase 210 in the example of Figure 11 is about 50 seconds. Generally, the duration of the fourth phase 210 can be between about 25 seconds and about 300 seconds, for example between about 50 seconds and about 150 seconds.

[0430] The control circuitry 5 can be configured to regulate the temperature of the heating device 6a, and / or the heating elements 6, 7 thereof based on measuring the resistance or electrical resistance of one or both heating elements 6, 7. The electrical resistance changes with the temperature, and hence the temperature can be controlled based on measuring the electrical resistance and controlling the energy storage 15 and / or heating elements 6, 7. The heating elements 6, 7 can be connected together in series. The control circuitry 5 can measure the current and the voltage to get the total resistance for both heating elements 6, 7 in series. The electrical resistance of the heater material can increase with the temperature. So, the total electrical resistance value given as the sum of the resistances of both heating elements 6, 7 can be used to regulate the temperature. In fact, the heating device 6a can act as temperature sensor.

[0431] The resistances of the heating elements 6, 7 can be very close to each other and the mechanical design around the heating device 6a can be symmetric so that both heating elements 6, 7 can have substantially the same temperature. Contact surfaces of the heating elements 6, 7 that contact the two opposing main faces 20a, 20b of the aerosol-forming article 20 can have the same width for the area in contact with the article 20.

[0432] A calibration in order to determine the temperature to resistance relation can be operated with thermocouples placed at the center of the article 20. A calibration process can be carried out with a fake aerosol-forming article 20 with two thermocouples inside the device 1 and then going through different fix temperature targets. Then based on this data, one or more, for example three, reference or calibration values of resistance versus temperature can be set or stored in the device memory. The same approach can be applied for the upstream heating device 70.Figure 12 illustrates a heating profile 300 for the upstream heating device 70 of an aerosolforming device 1, as described herein. As noted above, the upstream heating device 70 can be configured to heat the substrate 23 by convection in a puff-on-demand heating operation.

[0433] The heating profile 300 is illustrated in Figure 12 in the form of measured temperature values fluctuating around a temperature curve 304 with target temperatures (in °C) that the upstream heating device 70 or its resistive heating element 71 should reach versus time (in seconds) during a usage session, and specifically during each puff or user inhalation. Curve 304 can also reflect different power levels, at which the upstream heating device 70 and / or resistive heating element 71 can be operated during a usage session, which are indicated at the second y-axis of Figure 12. Moreover, curve 302 in Figure 12 shows the actual temperature of the upstream heating device 70 and / or resistive heating element 71 during the usage session.

[0434] Similar to the heating profiles 200 for the heating device 6a, the heating profile 300 for the upstream heating device 70 can define one or more target temperatures that should be reached during one or more, for example all, user inhalations during a usage session. Therein, the same target temperatures may be defined for all puffs or user inhalations, or at least some target temperatures may be different for some user inhalations. For instance, the target temperature may increase or decrease with progressing time from the start of the usage session.

[0435] The exemplary heating profile 300 shown in Figure 12 has a maximum duration of about 350 seconds and hence may be selected simultaneously to or upon selecting heating profile 200 of Figure 10 for the heating device 6a.

[0436] In the example of Figure 12, the target temperatures are identical for all user inhalations, such that the heating profile 300 comprises or defines a series of identical pulses or peaks 301, which correspond to the duration of single user inhalations or puffs taken by the user during the usage session. When a user inhalation occurs, the upstream heating device 70 can be operated by the control circuitry 5 at a second power level P2, such that the upstream heating device 70 and / or the resistive heating element 71 thereof is heated to a target temperature between about 270°C to about 500°C, for example from about 270°C to about 450°C, or for example from about 270°C to about 320°C, in particular from about 280°C to about 310°C, preferably about 300° C, as shown in the example of Figure 12.

[0437] At times where no puff or user inhalation occurs, the upstream heating device 70 and / or resistive heating element 71 can be operated by the control circuitry 5 at a first power level which can be much lower than the second power level P2. In an example, the first power level PT can be below about 80%, below about 70%, below about 60%, below about 50%, below about 40%, below about 30%, below about 20%, below about 10%, below about 5%, or below about 2% of the second power level P2. Accordingly, powering the upstream heating device 70 at the first power level PT at times where no user inhalation occurs, may only require a fraction of theenergy or power required to power the upstream heating device 70 at the second power level P2during a puff or user inhalation to generate aerosol. Hence, a significant amount of electrical energy can be saved by this approach.

[0438] It should be noted that the first power level PT can be zero, which can mean that the voltage and current to the upstream heating device 70 can be cut completely between two consecutive puffs, respectively, that the upstream heating device 70 is deactivated when no user inhalation occurs. Alternatively, the first power level PT can be non-zero, for example such that the upstream heating device 70 is heated to a pre-heating temperature at times where no puff or user inhalation occurs. Also a combination thereof may be applied, which means for or after some puffs the power level may be reduced to zero and for or after some other puffs in a usage session a non-zero power level PT may be applied.

[0439] As noted above, Figures 12 and 13 show measured temperature values of the resistive heating element 71 and / or upstream heating device 70. Therefore, fluctuations in the measured temperature values are shown in Figures 12 and 13 that occur between user inhalations or puffs. These fluctuations result from measurement only and do not correspond to the temperature profiles 300, shown in dashed line 304, of the upstream heating device 70 between puffs or user inhalations, where the second heating device 70 may be deactivated or powered at the constant power level P^

[0440] The upstream heating device 70 and / or its resistive heating element 71 can be activated or switched to the second power level P2in correspondence of the occurrence of a puff or user inhalation. This can provide a boost of energy to preheat the incoming air in the upstream airflow path 40a, which then will cross the substrate 23 placed between the heating elements 6, 7 of the heating device 6a. For controlling the upstream heating device 70 in correspondence with the user inhalations taken by the user, the user inhalations can be detected by the control circuitry 5 based on determining one or more of a change in the temperature of the heating device 6a and a change in the upstream heating device 70. Alternatively or additionally, a dedicated puff sensor may be used.

[0441] The heating profile 300 can be applied in addition to one of the heating profiles 200 for the heating device 6a. The duration of the usage session shown in Figure 12 is exemplary only, and can for example be adapted in accordance with a maximum duration defined by the currently selected heating profile 200 for the heating device 6a.

[0442] When the upstream heating device 70 is powered at the first power level P-, , it can be preheated to a pre-heating temperature. The pre-heating temperature, to which the upstream heating device 70 may optionally be heated, may be above about 25°C, above about 30°C, preferably above about 40°C, more preferably above about 50°C, and even more preferably above about 60°C. Alternatively or additionally, the pre-heating temperature can be below about 120°C, belowabout 100°C, preferably below about 90°C, more preferably below about 80°C, and even more preferably below about 70°C.

[0443] The upstream heating device 70 can particularly be used as puff or inhalation sensor based on sensing, monitoring or determining one or more changes in the temperature of the upstream heating device 70 by the control circuitry 5, because the upstream heating device 70 and / or its resistive element 71 can have a much lower thermal mass compared to the heating elements 6, 7 of the heating device 6a. Alternatively or additionally, however, one or more changes in the temperature of the heating device 6a or its heating elements 6, 7 can be determined by the control circuitry 5 to detect a user inhalation.

[0444] Figure 13 illustrates another exemplary heating profile 300 for the upstream heating device 70 and / or its resistive hating element 71. Unless stated otherwise, the disclosure about the heating profile 300 of Figure 12 equally applies to the heating profile 300 of Figure 13.

[0445] The exemplary heating profile 300 shown in Figure 13 has a maximum duration of about 500 seconds and hence may be selected simultaneously to or upon selecting heating profile 200 of Figure 9 for the heating device 6a.

[0446] The heating profile 300 of Figure 13 defines user inhalations 301a, during which the upstream heating device 70 is heated to the defined target temperature, analogue to user inhalations 301 shown in the heating profile 300 of Figure 12. In contrast to the example of Figure 12, however, the heating profile 300 of Figure 13 defines one or more user inhalations 301b, 301c of a usage session, during which the power supplied to the upstream heating device 70 is smaller than the power supplied during other user inhalations 301a of the usage session, or during which the power is cut completely, respectively, the upstream heating device 70 is deactivated, switched off or not powered. Alternatively or additionally, the target temperatures defined for the one or more user inhalations 301b, 301 c may be lower than the target temperatures defined for the user inhalations 301a.

[0447] For example, the heating profile 300 may define a number or count of user inhalations since the start of the usage session and a corresponding target temperature or power level for the upstream heating device 70. Optionally, the control circuitry 5 may be configured to determine the number or count of user inhalations during a usage session and apply the respective target temperature and / or power level based thereon.

[0448] The heating profile 300 of Figure 13 specifically defines that during the second and third user inhalations 301b from the start of the usage session, no power is supplied to the upstream heating device 70, respectively that the target temperature is reduced to ambient or room temperature. Any one or more user inhalations after the first user inhalation in a usage session can be skipped, respectively the power supply may be reduced. These user inhalations 301b may be in the first phase 204 or second phase 206 of the usage session. This may allow to tune theamount of aerosol generated in the third phase 206 of the usage session. It is noted that also more than two user inhalations 301b or only one may be defined in the heating profile 300.

[0449] Moreover, the heating profile 300 defines three further user inhalations 301c at the end of the usage session, for example at the end of the third phase 208 or fourth phase 210, during which the upstream heating device 70 is deactivated or at least powered at a lower power level compared to user inhalations 301 a (or operated at a low target temperature, e.g., ambient or room temperature). This may allow to compensate for the high temperature of the substrate 23 towards the end of the usage session. It is noted that also more or less than three user inhalations 301c may be defined in the heating profile 300.

[0450] With respect to user inhalations 301b and 301c, it is also noted that usually a user does not take puffs in perfect intervals as shown in Figure 12-13. For example, the missing or skipping of puff heating at user inhalations 301b can be puff-count based, as explained above, and / or can be time-period based, for example meaning that the user simply did not take puffs in the intervals 301b. For example, if no puffs are taken between 15-100 seconds as shown in Figure 13, there may be no need to skip the upstream air heating by the second heating device 70. Accordingly, the missing or skipping of powering the second heating device 70 at user inhalations 301b and / or 301 c can be enforced or caused by one or more of a puff count from the start of the usage session, a puff count from the start of the first puff, and a given or predetermined time period after start of the heating and / or the usage session. Alternatively or additionally, a threshold, temperature may be defined for the first heating device 6a, and upon reaching this threshold temperature, the second heating device 70 may not be powered during a user inhalation, for example as shown with user inhalation or interval 301c in Figure 13. Again, it is emphasized that any one or more user inhalations 301b, 301c after the first user inhalation in a usage session can be skipped by the control circuitry 5 for aerosol tuning.

[0451] Also it is emphasized that during the second phase 206, the third phase 208 and / or the fourth phase 210 one or more user inhalations 310b, 301c may be defined, during which the upstream heating device 70 may not be powered or powered at a lower power level, respectively, at operated at a lower target temperature compared to other user inhalations.

[0452] Moreover, at which user inhalations 301b, 301c of a usage session the power to the upstream heating device 70 may be reduced or cut completely may depend on a number of factors, and in particular on the heating profile 200 selected for the heating device 6a. Hence, by defining one or more user inhalations 301b, 301c, at which the power or target temperature is reduced, can allow to adapt the overall heating, for example to the heating profile 200 selected for the heating device 6a. Optionally, the heating profiles 200 of the heating device 6a may each define a heating profile 300 for the upstream heating device 70, or vice versa. Alternatively or additionally, the control circuitry 5 may be configured to select a heating profile 300 for theupstream heating device 70 based on the selected heating profile 200 for the heating device 6a, or vice versa.

[0453] Figure 14 shows a flow chart illustrating a method of controlling an aerosol-forming device 1 or system 4 comprising a heating device 6a configured to heat at least a part of an aerosolforming article 20 or substrate 23 to form aerosol, wherein the heating device 6a comprises two opposing heating elements 6, 7 defining a heating volume 30a therebetween that is configured to receive at least a part of the aerosol-forming article 20. The aerosol-forming device 1 or system 4 can be any one of the devices 1 or systems 4 described herein.

[0454] At step S1, the method may comprise increasing a temperature of the heating elements 6, 7 in a first phase 204 of a usage session from an initial temperature to a first target temperature, based on controlling a supply of power to the heating elements 6, 7, by a control circuitry 5 of the aerosol-forming device 1.

[0455] At step S2, the method may comprise decreasing the temperature of the heating elements 6, 7 in a second phase 206 of the usage session, for example to a second target temperature.

[0456] At step S3, the method may comprise increasing the temperature of the heating elements 6, 7 in a third phase 208 of the usage session. For example, the temperature may be increased to a third target temperature in the third phase 208.

[0457] Any one or more further functions or steps described with reference to any of the previous figures can be performed in the course of the method of Figure 14.

[0458] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

[0459] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in theart and practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0460] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS1. An aerosol-forming device, comprising:a heating device configured to heat at least a part of an aerosol-forming substrate or article to form aerosol, wherein the heating device comprises at least two opposing heating elements defining a heating volume therebetween that is configured to receive at least a part of the aerosolforming article; andcontrol circuitry configured to control a temperature of the heating elements during a usage session based on controlling a supply of power from a power source of the aerosol-forming device to the heating device, wherein the control circuitry is configured to:increase the temperature of the heating elements in a first phase of the usage session from an initial temperature to a first target temperature;decrease the temperature of the heating elements in a second phase of the usage session; andincrease the temperature of the heating elements in a third phase of the usage session, wherein a second target temperature of the second phase is in a range from about 200°C to about 290°C, in particular from about 210°C to about 280°C, for example from about 220°C to about 270°C, preferably from about 220°C to about 250°C; and / orwherein a third target temperature of the third phase is in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.

2. The aerosol-forming device according to the preceding claim, wherein the heating volume defined by the two opposing heating elements has a substantially rectangular parallelepiped shape and / or is configured to removably receive at least a part of a substantially rectangular parallelepiped shaped aerosol-forming article.

3. The aerosol-forming device according to any one of the preceding claims, wherein the two heating elements are arranged and configured to heat two opposing main faces of the aerosolforming article, when the aerosol-forming article is at least partly arranged in the heating volume.

4. The aerosol-forming device according to any one of the preceding claims, wherein the control circuitry is configured to decrease the temperature of the heating elements in the second phase of the usage session from the first target temperature to a second target temperature below the first target temperature.

5. The aerosol-forming device according to the preceding claim, wherein the control circuitry is configured to increase the temperature of heating elements in the third phase of the usage session from the second target temperature to a third target temperature above the second target temperature.

6. The aerosol-forming device according to any one of the preceding claims, wherein the first target temperature is in a range from about 270°C to about 320°C, in particular from about 275°C to about 310°C, for example from about 275°C to about 300°C, preferably from about 280°C to about 290°C.

7. The aerosol-forming device according to any one of the preceding claims, wherein the control circuitry is further configured to:maintain the temperature substantially constant during a fourth phase of the usage session.

8. The aerosol-forming device according to any one of the preceding claims, wherein the control circuitry is configured to control the temperature of the heating elements based on at least one heating profile defining a course of the temperature of the heating elements over time during the usage session, preferably wherein the at least one heating profile is stored in a data storage of the aerosol-forming device.

9. The aerosol-forming device according to the preceding claim, wherein different heating profiles differ from each other in one or more of a maximum duration of a usage session and an average temperature of the heating elements during the usage session.

10. The aerosol-forming device according to the preceding claim, wherein the longer the maximum duration of a usage session associated with one of the heating profiles is, the lower is the average temperature of the heating elements during the respective usage session; and / or wherein the shorter the maximum duration of a usage session associated with one of the heating profiles is, the higher is the average temperature of the heating elements during the respective usage session.

11. The aerosol-forming device according to any one of the preceding claims, further comprising:an upstream airflow path arranged upstream of the heating device, wherein the upstream airflow path is in fluid communication with an external environment of the aerosol-forming device, such90 / 91that air is drawable by a user in a user inhalation from the external environment through the upstream airflow path towards the heating volume; andan upstream heating device arranged in thermal contact with the upstream airflow path and configured to convectively heat air in the upstream airflow path to heat at least heat a part of a substrate of the aerosol-forming article.

12. The aerosol-forming device according to the preceding claim, wherein the upstream heating device is configured to perform a puff-on-demand heating operation; and / or wherein the control circuitry is configured to control the upstream heating device to perform a puff-on-demand heating operation.

13. The aerosol-forming device according to claim 11 or 12, wherein the control circuitry is configured to control the temperature of the upstream heating device based on at least one predetermined heating profile defining at least one target temperature of the upstream heating device, to which the upstream heating device is to be heated during a user inhalation.

14. The aerosol-forming device according to the preceding claim, wherein the at least one heating profile of the upstream heating device defines one or more user inhalations of a usage session, during which one or more user inhalations a power supplied to the upstream heating device is smaller than a power supplied during other user inhalations of the usage session.

15. An aerosol-forming system comprising an aerosol-forming device according to any one of the preceding claims and one or more of: an aerosol-forming article for generating aerosol; and a companion device for one or more of storing the aerosol-forming device and charging the aerosolforming device.

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