Aerosol-generating device comprising a combustible fuel as a power source

Abstract

An aerosol generating device (1) comprises: a heating cavity (2) for accommodating at least a part of an aerosol generating substrate (11); a fuel tank (3) for storing a fuel; and an ignition chamber (4) in fluid communication with a fuel outlet (12) of the fuel tank (3). The ignition chamber (4) is configured to ignite the fuel from the fuel tank (3) to cause a combustion of the fuel. The ignition chamber (4) is further configured to transfer the heat resulted from the fuel combustion to the heating cavity (2). The aerosol generating device (1) further comprises a thermal energy harvesting device (5) electrically connected to one or more electrical components (6) of the aerosol generating device (1) to supply electrical energy. The thermal energy harvesting device (5) arranged such that the thermal energy harvesting device (5) receives at least a part of heat generated by the combustion of the fuel in the ignition chamber (4) and generates electrical energy. The one or more electrical components (6) comprises a fuel supply controller (7) to control delivery of the fuel from the fuel tank (3) to the ignition chamber (4).

Description

[0001] Aerosol-generating device comprising a combustible fuel as a power source

[0002] Technical field

[0003] The present invention relates to an aerosol generating device. The invention especially relates to an aerosol generating device employing a combustible fuel as a power source for heating. The invention also relates to a method of aerosol generation using such a device.

[0004] Technical background

[0005] Heat-not-burn (HNB) technology represents a significant innovation in the realm of tobacco consumption, offering a potentially less harmful alternative to traditional smoking. Unlike conventional cigarettes that bum tobacco at high temperatures, HNB devices heat tobacco to a lower temperature, sufficient to release nicotine and flavors without combustion. HNB devices generate an aerosol or vapour by heating an aerosol generating material to a temperature typically in the range between 150°C and 300°C, and in some cases as high as 350°C. This process significantly reduces the production of undesirable chemicals typically associated with burning tobacco.

[0006] The majority of HNB devices on the market today are electrically powered, often referred to as electronic cigarettes or e-cigarettes. These devices use battery-powered heating elements to control the temperature, ensuring that the tobacco is heated to an optimal level to produce vapor without reaching combustion temperatures.

[0007] In addition to electrically powered devices, there are also non-electric HNB devices that utilize combustible fuels to generate the necessary heat. These devices may offer the significant advantage of not requiring batteries or electrical components, making them a compelling alternative to existing electronic cigarettes.

[0008] Most e-cigarettes carry a large and expensive battery because a high-quality battery is essential to provide a consistent puff experience throughout the session. Without a reliable battery, the device cannot maintain the necessary power levels, leading to an inconsistent user experience. Additionally, users generally prefer not to charge theirdevices frequently, which necessitates a battery of a certain size to ensure longer usage times between charges. This requirement imposes a limitation on the size of e-cigarettes, preventing them from being smaller and more compact. Furthermore, the cost of e-cigarettes is influenced by the need for high-quality batteries and associated electronics, which cannot be significantly reduced without compromising performance and reliability. On the other hand, non-electric HNB devices use a fuel tank storing a combustible fuel for example, butane. If butane is used as fuel, the tank with a volume similar to that of an 18650 battery may provide about ten times more stick sessions than a battery-operated device. This means that the non-electric HNB device may be smaller and more portable. Moreover, devices without the need for batteries or electronic circuits may be less prone to technical malfunctions and can be more durable over time. The absence of batteries means users do not need to worry about charging their devices. This can be especially advantageous for users who are frequently on the go or in situations where access to electricity is limited. By eliminating the need for batteries, non-electric HNB devices would also reduce electronic waste.

[0009] While these devices offer these notable advantages, they also present some challenges that need to be addressed. One of the main challenges is the inability to precisely control the heating process. Without precise temperature regulation, there is a risk of overheating the tobacco, which can lead to the production of undesirable combustion. Additionally, non-electric HNB devices can experience energy loss at the initial stages of heating. Combustion fuels tend to emit more heat at the beginning of the combustion process, which can result in an initial burst of energy that is not efficiently utilized.

[0010] It is therefore desirable to provide an aerosol generating device based on a combustion fuel, which achieves an improved heating efficiency and heating control. It is also desirable to provide such an aerosol generating device which offer a reduced energy loss at initial stages of combustion of the fuel.

[0011] Summary of the Disclosure

[0012] According to a first aspect of the present invention, there is provided an aerosol generating device comprises: a heating cavity for accommodating at least a part of anaerosol generating substrate; a fuel tank for storing a fuel, the fuel tank comprising a fuel outlet; and an ignition chamber in fluid communication with the fuel outlet.

[0013] The ignition chamber is configured to ignite the fuel from the fuel tank to cause a combustion of the fuel. The ignition chamber is further configured to transfer the heat resulted from the fuel combustion to the heating cavity.

[0014] The fuel may comprise a combustible fluid fuel. In one exemplary embodiment, the fuel may comprise butane.

[0015] As it is known in fuel combustion technology, the fuel is supplied to the ignition chamber where the fuel combusts in the presence of oxygen. Therefore, the ignition chamber may be in fluid communication with the exterior atmosphere to ensure a supply of oxygen. According to some embodiment, the ignition chamber may comprise an ignition source for initiating the combustion process. Suitable ignition sources may include a ferrocerium rod with a striker, a spark plug, a piezoelectric igniter, or an electronic ignition system. The aerosol generating device may further comprise a fuel injector or nozzle for delivering the fuel into the ignition chamber. The ignition chamber may comprise an air intake system. The air intake system may include components to manage airflow, such as air filters and ducts. The ignition chamber may comprise an air exhaust system to expel the combustion gases. The ignition chamber may additionally comprise one or more sensors, such as a temperature sensor to ensure the ignition chamber remains within safe operating limits.

[0016] The ignition chamber is designed to withstand high temperatures and pressures generated during combustion. The ignition chamber may be made of heat-resistant materials.

[0017] Preferably, at least a part of walls of the heating cavity is in contact with at least a part of the ignition chamber to transfer heat from the ignition chamber by heat conduction.

[0018] Alternatively, or additionally, a heat transfer element may be arranged between the heating cavity and the ignition chamber.The aerosol generating device further comprises a thermal energy harvesting device electrically connected to one or more electrical components of the aerosol generating device to supply electrical energy.

[0019] The thermal energy harvesting device is configured to receive at least a part of the heat generated by the combustion of the fuel in the ignition chamber and generates electrical energy. The heat may be received from the heating cavity which has been heated by the heat from the ignition chamber, and / or directly from the ignition chamber.

[0020] The thermal energy harvesting device may be arranged adjacent to the heating cavity to receive the heat from the heat cavity.

[0021] Preferably, the thermal energy harvesting device is in contact with the heating cavity. In one exemplary embodiment, the heating cavity is a tubular cavity for inserting an aerosol generating stick comprising the aerosol generating substrate, and the thermal energy harvesting device is arranged to surround a periphery of the heating cavity.

[0022] As described above, thermal energy harvesting device is configured to generate electrical energy from the combustion heat, and to supply the energy to the one or more electrical component.

[0023] The one or more electrical components comprises a fuel supply controller to control delivery of the fuel from the fuel tank to the ignition chamber. The flow rate of the fuel supplied to the ignition chamber during combustion process is a primary parameter controlling the combustion reaction. The rate and efficiency of combustion reaction determines the heat generated in the ignition chamber, which in turn affects the temperature of the heating cavity.

[0024] Because the combustion is essentially a reaction between the fuel and oxygen, not only the amount of fuel but also the amount of oxygen plays a crucial role. The amount of oxygen significantly affects how the fuel is combusted. If there is insufficient oxygen, incomplete combustion may occur, leading to the production of undesirable chemicals such as carbon monoxide. If there is excess oxygen, the combustion efficiency may reduce because heat may be absorbed by the excess oxygen, although this ensures the complete combustion of the fuel.In the present invention, the fuel supply is actively controlled by the fuel supply controller, while the oxygen amount may remain unadjusted, for example, similar to that in the atmosphere. This configuration has been found effective for controlling the combustion reaction while preventing incomplete combustion.

[0025] As described above, the aerosol generating device of the present invention is configured to heat the heating cavity by heat of combustion of the fuel, while simultaneously harvesting energy from the heat of combustion of the fuel to power the one or more electrical components to control the combustion reaction. In this way, the aerosol generating device is autonomous; it does not require external electrical charging, while maintaining the benefits of electronic controls allowing a precise heat control of the heating cavity.

[0026] According to some embodiment, the fuel supply controller may comprise an electric fluid flow control device arranged between the fuel tank and the ignition chamber. The fuel supply controller may be configured to electrically control operation of the electric fluid flow control device to adjust the flow rate of the fuel from the fuel tank to the ignition chamber.

[0027] The electric fluid flow control device may comprises a pump, a valve, or a variable flow regulator.

[0028] Preferably, the electric fluid flow control device is a digital valve.

[0029] Preferably, the electric fluid flow control device is a digital valve configured to perform valve on / off operation employing pulse width modulation (PWM).

[0030] The flow control using PWM of the valve allows for very precise control over the flow rate by adjusting the duty cycle, which is the proportion of time the valve is open versus closed within each cycle. The PWM control, which requires the valve to be fully open or closed, may also reduce the energy consumption compared to a control where the valve position is continuously adjusted for altering a degree of opening of the valve.

[0031] Preferably, the one or more electrical components further comprises control unit, and / or one or more sensors. The control unit, and the one or more sensors are configured to function with the fuel supply controller to manage the fuel flow control. More specifically,these components perform functions related to fuel flow control, such as monitoring fuel pressure, temperature, and flow rate, and making real-time adjustments to maintain optimal fuel supply during the session. In addition to their primary role in fuel flow control, these electrical components may also have other functions. For instance, these electrical components are configured to shut off the fuel supply in case of a malfunction.

[0032] Furthermore, the one or more electrical components may also comprise a display, LED indicator, user interfaces, such as buttons, and a touch screen allowing users to control various functions related to fuel flow. These interfaces enable users to adjust settings, monitor system status, and customize their experience, providing greater flexibility and control. By working together, these components ensure that the fuel supply system operates smoothly, efficiently, and safely, providing a consistent and reliable user experience.

[0033] According to some preferred embodiment, the thermal energy harvesting device comprises one or more thermoelectric generators (TEGs) or pyroelectric generators. A TEG comprises a Peltier module that produce electrical energy when thermoelectric materials are exposed to a heat gradient. The Peltier module comprises one side of the module which is exposed to a heat source (a hot side) and the other side which is kept cooler (a cold side). The temperature difference between the hot and cold sides creates a voltage across the module thanks to Seebeck effect.

[0034] A pyroelectric generator comprises a pyroelectric material that undergoes a shift in its internal polarization, when the material experiences a change in temperature. The shift in polarization creates a voltage across the material, thereby generating electrical power. According to some embodiment, the thermal energy harvesting device a TEG. The TEG comprise a first side (the hot side) and a second side (the cold side), wherein electrical energy is generated when there is a temperature gradient between the first side and the second side. The TEG are arranged in the aerosol generating device such that the first side faces to the heating cavity or the ignition chamber to receive the heat, while the second side faces away from the heating cavity or the ignition chamber so that the second side may be kept at a lower temperature than the temperature at the first side.According to some embodiment, the thermal energy harvesting device may comprise a pyroelectric generator. In this case, the pyroelectric generator is arranged adjacent to the heating cavity or the ignition chamber. In this way, the pyroelectric generators may effectively receive the heat when the ignition process starts. An increase of temperature that the pyroelectric generators experience resulting in generation of electrical energy. According to some embodiment, the thermal energy harvesting device may comprise one or more thermophotovoltaic (TPV) cells that convert thermal radiation (infrared radiation) to electrical energy by the photovoltaic effect.

[0035] According to some embodiment, the thermal energy harvesting device may comprise one or more Stirling engines that drive the energy generator (e.g., a piston) by expansion of fluid (gas) when the fluid is heated, thereby generating electrical energy from thermal energy.

[0036] According to some embodiment, the thermal energy harvesting device may be at least partially in contact to an external surface of a wall of the heating cavity. In this way, the thermal energy harvesting device may efficiently receive heat from the heating cavity by heat conduction.

[0037] According to some embodiment, the thermal energy harvesting device may be arranged to at least partially surround the heating cavity. In one exemplary embodiment, the heating cavity may be a tubular cavity for inserting an aerosol generating stick comprising the aerosol generating substrate. In such a case, the thermal energy harvesting device is preferably arranged to surround a periphery of the heating cavity.

[0038] According to some embodiment, the thermal energy harvesting device may comprise a Peltier module arranged such that a hot side of the Peltier is facing to the heating cavity whereas a cold side of the Peltier module is facing way from the heating cavity.

[0039] In one exemplary embodiment, wherein the heating cavity is tubular, the Peltier module has a tubular shape comprising the hot side on an inner surface and the cold side on an outer surface. The Peltier module is designed such that the inner surface is attached to the exterior surface of a sidewall of the heating cavity.According to some embodiment, the aerosol generating device may comprise an energy storage device configured to store the energy generated by the thermal energy harvesting device.

[0040] The energy storage device may be configured to supply power to the one or more electrical components.

[0041] The amount of energy generated by the thermal energy harvesting device varies during the combustion process. For instance, the thermal energy harvesting device comprising TEG or pyroelectric generator would produce more electrical energy at the initial stages of combustion where the thermal energy harvesting device experience continuous temperature changes. Therefore, storing at least part of the electrical energy generated at this stage for subsequent use may allow a more consistent power supply to one or more electrical components throughout a session. Moreover, the stored energy remaining in the energy storage device at the end of the session can be used for the next session. This approach may enable powering the electrical components from the start of the session (at the start of the combustion process), when both the heating cavity and the ignition chamber are at ambient temperature.

[0042] According to some embodiment, the energy storage device may comprise at least one of a battery or a supercapacitor. The battery may be a rechargeable battery, such as a lithium-ion battery.

[0043] Preferably, the fuel comprises a hydrocarbon, such as butane. The aerosol generating device utilizes combustion of butane or other hydrocarbons may a rapid heating at the beginning of each session. Thanks to the highest energy density achievable by these hydrocarbon fuels, such an aerosol generating device may offer an increased number of sticks per a certain volume of a fuel tank. Alternatively, the aerosol generating device may achieve a more compact design.

[0044] According to another aspect of the present invention, there is provided a method of aerosol generation comprising steps of:

[0045] - providing the aerosol generating device according to any one of the preceding embodiments, and inserting an aerosol generating substrate in the heating chamber;- introducing the fuel from the tank to the ignition chamber, and generating heat in the ignition chamber by combusting the fuel from the fuel tank;

[0046] - generating electrical energy by the thermal energy harvesting device using at least a part of the heat generated in the ignition chamber; and

[0047] - supplying the electrical energy to the one or more electrical components.

[0048] At step of providing the aerosol generating device, the aerosol generating substrate may be a part of an aerosol generating article, for example in the form of a cigarette stick. Before starting a vaping session, the aerosol generating substrate is inserted into the heating cavity of the aerosol generating device.

[0049] At step of introducing the fuel from the tank to the ignition chamber, a user may press an ignition button to ignite the fuel. The heating cavity subsequently receives the heat generated by fuel combustion in the ignition chamber, which in turn heats the aerosol generating substrate of the aerosol generating article to generate vapor.

[0050] At step of supplying the electrical energy to the one or more electrical components, the one or more electrical components is operated to adjust the flow rate of the fuel from the fuel tank to the ignition chamber such that the temperature of the heating chamber is precisely controlled throughout the vaping session.

[0051] When the one or more electrical components include the one or more temperature sensors configured to measure the temperature of the heating cavity, the fuel supply controller may be configured such that the electric fluid flow control device adjusts the flow rate based on difference between the temperature measured by the one or more temperature sensors and a predetermined target temperature.

[0052] When the one or more electrical components include the one or more pressure sensors configured to measure the flow rate of the fuel, the fuel supply controller may be configured such that the electric fluid flow control device is operated to achieve a predetermined flow rate profile so that the temperature of the heating cavity may be maintained at the predetermined target temperature.

[0053] When the aerosol generating device comprises the energy storage device, the method may further comprise a step of storing the electrical energy generated at the step ofgenerating electrical energy by the thermal energy harvesting device to the energy storage device before or during supplying the electrical energy to the one or more electrical components at the step of supplying the electrical energy to the one or more electrical components.

[0054] Preferably, the energy storage device is configured to efficiently store energy especially at initial stages of the session.

[0055] Combustion fuels tend to emit more heat at the beginning of the combustion process. Although the initial stages of the session normally require more energy to heat up the aerosol generating substrate, this initial burst of energy may still cause significant loss of energy.

[0056] In addition, when the energy harvesting device is the generation of energy by the thermal energy harvesting device comprises the Peltier module, the generation of energy may occur more intensively at the initial stages, where a temperature increase of the heating cavity and the ignition is in progress.

[0057] In some embodiments, the heat is first transferred to the hot side of the Peltier module, resulting in an increase in the temperature of the hot side, while the cold side remains at ambient temperature. Subsequently, a part of the heat is transferred from the hot side to the cold side, causing the temperature of the cold side to start increasing. Although the temperature of the cold side begins to rise later than that of the hot side, the temperatures of both sides will become similar as the session progresses. Therefore, the maximum temperature difference between the hot side and the cold side may be achieved at the initial stages.

[0058] In one exemplary embodiment, the electrical energy generated by the thermal energy harvesting device may be stored to the energy storage device before supplying the electrical energy to the one or more electrical components. This way, the loss of energy at the initial stage may be minimized.

[0059] Alternatively, the electrical energy generated by the thermal energy harvesting device may be partially stored to the energy storage device while the rest of the electrical energy is supplied to the one or more electrical components.Brief Description of the Drawings

[0060] Figure 1A shows a schematic of an aerosol generating device and an aerosol generating article comprising an aerosol generating substrate according to an embodiment of the present invention;

[0061] Figure 1B illustrates a cross-sectional view of the aerosol generating device and the aerosol generating article comprising the aerosol generating substrate;

[0062] Figure 2 illustrates a cross-sectional view of the aerosol generating device and the aerosol generating article comprising the aerosol generating substrate according to another embodiment;

[0063] Figure 3A displays steps of a method of aerosol generating in one example;

[0064] Figure 3B displays steps of a method of aerosol generating in another example; and Figure 4 depicts a diagram showing temperature variations at a hot side and a cold side of a thermal energy harvesting device (a Peltier) over duration of a vaping session.

[0065] Detailed Description of Embodiments

[0066] Figure 1 A shows a schematic of an aerosol generating device 1 and an aerosol generating article 10 comprising an aerosol generating substrate 11 according to an embodiment of the present invention and Figure 1B illustrates a cross-sectional view of the aerosol generating device 1 and the aerosol generating article 10 comprising the aerosol generating substrate 11.

[0067] An aerosol generating device 1 comprises a heating cavity 2 designed to accommodate at least a part of an aerosol generating substrate 11. In this example, the aerosolgenerating substrate 11 is a part of an aerosol-generating article 10 in the form of a stick, similar to a cigarette.

[0068] The heating cavity 2 may be a tubular cylindrical cavity with an open end 13 and a closed end 14. The open end 13 is configured to allow the insertion of the aerosol-generating article 10. The aerosol generating device 1 is configured to heat the heating cavity 2 togenerate aerosol form the aerosol generating substrate 11 received in the heating cavity 2.

[0069] The aerosol generating device 1 utilizes combustion of a fuel as a heat source to heat the aerosol generating substrate 11. The fuel comprises a combustible fluid fuel. Preferably, the fuel may comprise butane.

[0070] The aerosol generating device 1 comprises a fuel tank 3 for storing the fuel. The fuel tank 3 comprising a fuel outlet 12.

[0071] The aerosol generating device 1 also comprises an ignition chamber 4 configured to ignite the fuel from the fuel tank 3 to cause a combustion of the fuel. The ignition chamber 4 is in fluid communication with the fuel outlet 12 to receive the fuel from the fuel tank 3. The ignition chamber 4 may comprise an ignition source for initiating the combustion process. For example, the ignition source may comprise a ferrocerium rod and a striker for scrape the ferrocerium rod to produce sparks.

[0072] The ignition chamber 4 is configured to transfer the heat resulted from the fuel combustion to the heating cavity 2.

[0073] Preferably, at least a part of walls of the heating cavity 2 is in contact with at least a part of the ignition chamber 4 to transfer heat from the ignition chamber 4 by heat conduction. As shown in Figure 1B, the ignition chamber 4 may be arranged adjacent to the closed end 14 of the heating cavity 2 such that a wall of the ignition chamber 4 is in thermal contact with a wall forming the close end of the heating cavity 2.

[0074] The aerosol generating device 1 further comprises a thermal energy harvesting device 5. The thermal energy harvesting device 5 may be arranged adjacent to the heating cavity 2 to receive the heat from the heat cavity. The thermal energy harvesting device 5 is configured to generate electrical energy from a part of the heat of the fuel combustion. Referring to Figure 1B, the thermal energy harvesting device 5 may comprise a thermoelectric generator (TEG) including a Peltier module. The Peltier module may have a tubular shape comprising a hot side on an inner surface and a cold side on an outer surface. The Peltier module may be designed such that the inner surface is attached to an external surface of a sidewall 15 of the heating cavity 2. In this way, the heat from theheating cavity 2 may be at least partially conducted from the external surface of a sidewall 15 of the heating cavity 2 to the hot side of the Peltier module.

[0075] The thermal energy harvesting device 5 is electrically connected to one or more electrical components 6 of the aerosol generating device 1 to supply electrical energy, and to supply the energy to the one or more electrical component. The one or more electrical components 6 comprises a fuel supply controller 7 to control delivery of the fuel from the fuel tank 3 to the ignition chamber 4.

[0076] For example, the fuel supply controller 7 may comprise an electric fluid flow control device 8 arranged between the fuel tank 3 and the ignition chamber 4. The fuel supply controller 7 is configured to electrically control the operation of the electric fluid flow control device 8 to adjust the flow rate of the fuel from the fuel tank 3 to the ignition chamber 4. In this example, the electric fluid flow control device 8 is a digital valve. The digital valve is configured to perform valve on / off operation employing pulse width modulation (PWM). The one or more electrical components 6 may further comprise control unit, and / or one or more sensors (not shown). The control unit, and the one or more sensors are configured to function with the fuel supply controller 7 to manage the fuel flow control. For example, the one or more sensors may comprise a temperature sensor arranged to measure temperature of the heating cavity 2. Alternatively, or additionally, the one or more sensors may comprise a temperature sensor arranged to measure temperature of the ignition chamber 4.

[0077] Furthermore, the one or more sensors may comprise a pressure sensor or a fluid flow sensor to measure a flow rate of the fuel to the ignition chamber 4.

[0078] The control unit may be configured to control the electric fluid flow control device 8. The control unit may be configured to monitor signals from the one or more sensors indicative of the state of the fuel supply, e.g., the flow rate of the fuel, and the temperature of the heating cavity 2 and / or the ignition chamber 4, and to make real-time adjustments to maintain optimal fuel supply during the session.Figure 2 illustrates a cross-sectional view of the aerosol generating device 1 according to another embodiment and the aerosol generating article 10 comprising the aerosol generating substrate 11.

[0079] The embodiment of the aerosol generating device 1 shown in Fig. 2 is similar to the embodiment shown in Figure 1 B, but it further comprises an energy storage device 9 configured to store the energy generated by the thermal energy harvesting device 5. The energy storage device 9 may comprise at least one of a battery (such as a lithium-ion battery) or a supercapacitor. The energy storage device 9 is configured to supply power to the one or more electrical components 6.

[0080] For example, during the session, the energy storage device 9 stores at least a part of the electrical energy generated by the thermal energy harvesting device 5 for subsequent uses during the session. This may allow a consistent power supply to one or more electrical components 6 throughout a session. Moreover, the stored energy remaining in the energy storage device 9 at the end of the session can be used for the next session, for example at the start of the combustion process, when both the heating cavity 2 and the ignition chamber 4 are at ambient temperature.

[0081] Figure 3A displays steps of a method 100 of aerosol generating in one example.

[0082] Before the start of a vaping session, the aerosol generating device 1, according to any one of the embodiments as described above, is provided, and an aerosol generating substrate 11 is inserted in the heating chamber (S101). The aerosol generating substrate 11 may be a part of an aerosol generating article 10, for example in the form of a cigarette stick. Before starting a vaping session, the aerosol generating substrate 11 is inserted into the heating cavity 2 of the aerosol generating device 1.

[0083] Firstly, the fuel from the tank is introduced to the ignition chamber 4, and heat is generated in the ignition chamber 4 by combusting the fuel from the fuel tank 3 (S102). For initiating the combustion process, a user may press an ignition button to ignite the fuel.

[0084] The heating cavity 2 subsequently receives the heat generated by fuel combustion in the ignition chamber 4, which in turn heats the aerosol generating substrate 11 of the aerosol generating article 10 to generate vapor.At least a part of the heat generated in the ignition chamber 4 is transferred to the thermal energy harvesting device 5, and the thermal energy harvesting device 5 generates electrical energy by the at least a part of the heat generated in the ignition chamber 4 (S103).

[0085] The electrical energy generated by the thermal energy harvesting device 5 is supplied to the one or more electrical components 6 (S104). As described earlier, the one or more electrical components 6 powered by the thermal energy harvesting device 5 are configured to control the flow of the fuel from the fuel tank 3 to the ignition chamber 4 for adjusting temperature of the heating cavity 2 to a target temperature. For example, the energy generated by the thermal energy harvesting device 5 is supplied to the fuel supply controller 7 to control delivery of the fuel from the fuel tank 3 to the ignition chamber 4. Figure 3B displays steps of a method 100’ of aerosol generating in another example. In this example, the aerosol generating device 1 comprises the energy storage device 9. The method 100’ of this embodiment is similar to the method 100 of Figure 3A, but the method 100’ further comprises a step (S105) of storing the electrical energy generated by the thermal energy harvesting device 5 to the energy storage device 9 before or during supplying the electrical energy to the one or more electrical components 6 of S104. The step of storing energy to the energy storage device 9 is further explained below. Figure 4 depicts a diagram showing temperature variations at a hot side and a cold side of a thermal energy harvesting device 5 (a Peltier) over duration of a vaping session. At the start of the session, the heat is generated at the ignition chamber 4 by combustion of the fuel. The heat is subsequently transferred to the heating cavity 2 and then to the hot side of the Peltier. Consequently, temperature of the hot side increases from the start of the session.

[0086] When temperature of the heating cavity 2 reaches a target temperature, the flow supply controller may adjust the flow of the fuel supplied to the ignition chamber 4 for stabilizing the temperature of the heating cavity. Because the hot side of the Peltier is in direct contact to the external surface of the heating cavity 2, temperature profile of the hot sidewill essentially be similar to that of the heating cavity 2. Therefore, at this stage (ti), temperature of the hot side will reach a stabilized temperature of the hot side TH.

[0087] At the cold side, temperature also increases due to heat conduction from the hot side through the Peltier module. Therefore, temperature of the cold side also starts to increase from the start of the session. However, the rate of temperature increase at the cold side may be lower than at the hot side. Due to heat transfer through the Peltier module, some delay in the temperature profile at the cold side may occur compared to the hot side. Thus, the temperature may continue to increase at the cold side even when the temperature of the hot side reaches a plateau (ti). Subsequently, at t=t2, the temperature at the cold side will stabilize at a stabilized temperature of the cold side Tc. The stabilized temperature at the cold side Tc may be lower than the stabilized temperature at the hot side TH because the cold side is located further from the heating cavity 2.

[0088] Based on the diagram, the maximum temperature difference between the hot side and the cold side may be achieved at the initial stages of the session when the temperature of the Peltier module is increasing (i. e. , t <t2). Therefore, the generation of energy will occur more intensively during the initial stages.

[0089] In one example, the electrical energy generated by the thermal energy harvesting device 5 may be stored to the energy storage device 9 before supplying the electrical energy to the one or more electrical components 6. This way, the loss of energy at the initial stage may be minimized.

[0090] Alternatively, the electrical energy generated by the thermal energy harvesting device 5 may be partially stored to the energy storage device 9 while the rest of the electrical energy generated is supplied to the one or more electrical components 6.

Claims

Claims1. An aerosol generating device (1) comprises:a heating cavity (2) for accommodating at least a part of an aerosol generating substrate (11);a fuel tank (3) for storing a fuel, the fuel tank (3) comprising a fuel outlet (12); an ignition chamber (4) in fluid communication with the fuel outlet (12), configured to ignite the fuel from the fuel tank (3) to cause a combustion of the fuel, the ignition chamber (4) further configured to transfer the heat resulted from the fuel combustion to the heating cavity (2); anda thermal energy harvesting device (5) electrically connected to one or more electrical components (6) of the aerosol generating device (1) to supply electrical energy, wherein the thermal energy harvesting device (5) is configured to receive at least a part of heat generated by the combustion of the fuel in the ignition chamber (4) and generate electrical energy,wherein the one or more electrical components (6) comprises a fuel supply controller (7) to control delivery of the fuel from the fuel tank (3) to the ignition chamber (4).

2. An aerosol generating device (1) according to claim 1, wherein the fuel supply controller (7) comprises an electric fluid flow control device (8) arranged between the fuel tank (3) and the ignition chamber (4).

3. An aerosol generating device (1) according to claim 2, wherein the electric fluid flow control device (8) comprises a pump, a valve, or a variable flow regulator.

4. An aerosol generating device (1) according to claim 3, wherein the electric fluid flow control device (8) is a digital valve configured to perform valve on / off operation employing pulse width modulation.

5. An aerosol generating device (1) according to any one of the preceding claims, wherein the one or more electrical components (6) further comprises control unit, and / or one or more sensors.

6. An aerosol generating device (1) according to any one of the preceding claims, wherein the thermal energy harvesting device (5) comprises one or more thermoelectric generators (TEGs) or pyroelectric generators.

7. An aerosol generating device (1) according to any one of the preceding claims, wherein the thermal energy harvesting device (5) is at least partially in contact to an external surface of a wall of the heating cavity (2).

8. An aerosol generating device (1) according to any one of the preceding claims, wherein the thermal energy harvesting device (5) is arranged to at least partially surround the heating cavity (2).

9. An aerosol generating device (1) according to any one of the preceding claims, wherein the thermal energy harvesting device (5) comprises a Peltier module arranged such that a hot side of the Peltier module is facing to the heating cavity (2) whereas a cold side of the Peltier module is facing way from the heating cavity (2).

10. An aerosol generating device (1) according to any one of the preceding claims, wherein the aerosol generating device (1) comprises an energy storage device (9) configured to store the energy generated by the thermal energy harvesting device (5).

11. An aerosol generating device (1) according to claim 10, wherein the energy storage device (9) is configured to supply power to the one or more electrical components (6).

12. An aerosol generating device (1) according to claim 10 or 11, wherein the energy storage device (9) comprises at least one of a battery or a supercapacitor.1913. An aerosol generating device (1) according to any one of the preceding claims, wherein the fuel comprises a hydrocarbon, such as butane.

14. A method of aerosol generation comprising steps of:providing an aerosol generating device (1) according to any one of the preceding claims and inserting an aerosol generating substrate (11) in the heating cavity (2);introducing the fuel from the tank to the ignition chamber (4), and generating heat in the ignition chamber (4) by combusting the fuel from the fuel tank (3);generating electrical energy by the thermal energy harvesting device (5) using at least a part of the heat generated in the ignition chamber (4); andsupplying the electrical energy to the one or more electrical components (6).

15. A method of aerosol generation according to claim 14, wherein when the aerosol generating device (1) comprises the energy storage device (9) of claim 12 or 13, the method further comprises a step of storing the electrical energy generated at the step of generating electrical energy to the energy storage device (9) before or during supplying the electrical energy to the one or more electrical components (6) at the step supplying the electrical energy to the one or more electrical components (6).

Images