EP4368049A1 - Control method of an aerosol generating device, and associated control system and aerosol generating system - Google Patents
Control method of an aerosol generating device, and associated control system and aerosol generating system Download PDFInfo
- Publication number
- EP4368049A1 EP4368049A1 EP22207142.5A EP22207142A EP4368049A1 EP 4368049 A1 EP4368049 A1 EP 4368049A1 EP 22207142 A EP22207142 A EP 22207142A EP 4368049 A1 EP4368049 A1 EP 4368049A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- aerosol generating
- electrically conductive
- electrodes
- conductive substrate
- measurements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- 239000000443 aerosol Substances 0.000 title claims abstract description 92
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000010438 heat treatment Methods 0.000 claims abstract description 27
- 238000002485 combustion reaction Methods 0.000 claims abstract description 9
- 239000000758 substrate Substances 0.000 claims description 92
- 238000005259 measurement Methods 0.000 claims description 27
- 238000009529 body temperature measurement Methods 0.000 claims description 13
- 241000208125 Nicotiana Species 0.000 claims description 9
- 235000002637 Nicotiana tabacum Nutrition 0.000 claims description 9
- 239000004020 conductor Substances 0.000 claims description 9
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 12
- 239000000463 material Substances 0.000 description 9
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000005070 sampling Methods 0.000 description 5
- 239000003610 charcoal Substances 0.000 description 4
- 235000019504 cigarettes Nutrition 0.000 description 3
- 230000002596 correlated effect Effects 0.000 description 3
- 235000011187 glycerol Nutrition 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 239000000796 flavoring agent Substances 0.000 description 2
- 235000019634 flavors Nutrition 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/50—Control or monitoring
- A24F40/57—Temperature control
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
- A24F40/46—Shape or structure of electric heating means
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
- A24D1/00—Cigars; Cigarettes
- A24D1/20—Cigarettes specially adapted for simulated smoking devices
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/20—Devices using solid inhalable precursors
Definitions
- the invention relates to a control method for an aerosol generating device.
- the invention also relates to a control system and an aerosol generating system associated to such a control method.
- the control method according to the invention allows operation of an aerosol generating device to generate aerosol from an aerosol generating article.
- Some aerosol generating devices deliver an inhalable aerosol by supplying electrical power using electrodes that sandwich an aerosol generating article.
- the aerosol generating article comprises a substrate formed of a mixture of tobacco material with charcoal or another conductive material which makes the substate electrically conductive. Electrical current is thus applied to the substrate through at least a pair of electrodes to directly heat the tobacco material contained therein to generate the inhalable aerosol.
- it has proven difficult so far to efficiently control power delivery to the electrically conductive substrate such that organoleptic properties of the tobacco material and aerosol generation capacity are not rapidly exhausted from the substrate due to excessive or permanent heating thereof due to inertia of the electrically conductive substrate and conductive material therein.
- An aim of the present invention is to control efficiently aerosol generation in such type of aerosol generating devices.
- the present invention provides a control method of power supply of at least a pair of electrodes comprised in an aerosol generating device, the aerosol generating device further comprising a heating space for receiving an aerosol generating article, the electrodes being arranged opposite to each other to sandwich an electrically conductive substrate of the aerosol generating article when it is received in the heating space.
- the control method comprises performing of a closed loop control based on measurements of both voltage and current supplied to the electrodes, to produce aerosol from the electrically conductive substrate without combustion.
- the control method according to the invention enables measurements of voltage and current passing through the electrically conductive substrate to control aerosol generation by the device.
- the control method of the invention uses a closed loop control, based on feedback parameters which are voltage and current supplied to the electrically conductive substrate.
- temperature measurements in the substrate are no longer required to control operation of the device.
- Such temperature measurements in the substrate can be challenging in practice due to the need of providing temperature sensors arranged for measuring temperature of the aerosol generating substrate within the mass thereof, such as thermocouples for instance, or contactless temperature sensing arrangements to infer temperature in the aerosol generating substrate in a contactless fashion, which are not always accurate.
- the method according to the invention leads therefore to a resulting control which is more accurate than any existing method relying on substrate temperature measurements.
- the closed loop control can perform a temperature control of the electrically conductive substrate, based on the measurements of voltage and current supplied to the electrodes.
- This is an indirect temperature control, since there is no need to measure the temperature of the electrically conductive substrate itself.
- This indirect temperature control is based on measuring and/or on assessing one or more parameters which are representative of this temperature while being different from this temperature.
- the temperature control of the electrically conductive substrate is performed by heating the electrically conductive substrate in such a way that the temperature of the electrically conductive substrate will simultaneously remain sufficiently high so as to generate the aerosol from the electrically conductive substrate, typically above 50°C, and sufficiently low so as to avoid combustion in the electrically conductive substrate, typically below 350°C.
- control method according to the invention can thus be more accurate than a conventional method using only temperature measurements.
- the temperature measurements are necessarily related to the environment and not only to the substrate, whereas the voltage and current measurements can characterize accurately the substrate itself. Thus, a higher accuracy of control can be achieved.
- the heating space is designed for receiving an aerosol generating article comprising a solid electrically conductive substrate.
- the substrate can be sandwiched between the electrodes .
- the electrodes being arranged opposite to each other form a gap which is substantially constant, whatever the state of the substrate (never consumed, half consumed or exhausted for example). Additionally, the electrodes remain in contact with the substrate, whatever the state of the substrate.
- the dimensions of the electrodes may be adapted to operate efficiently with the electrically conductive substrate of an aerosol generating article.
- the electrodes may cover at least 25%, advantageously 50%, preferably 75% and even more preferably 100%, of the surface area of the electrically conductive substrate of an aerosol generating article provided in the gap between the electrodes as measured in a plane parallel to electrodes contact surfaces with the aerosol generating article.
- the broader the contact surface between the electrodes and the aerosol generating article the more efficient the current can be conducted through the substrate to heat it and generate an inhalable aerosol therefrom.
- Preferred embodiments comprise one or more of the following features, which can be taken separately or in combination.
- the closed loop control does not include any substrate temperature feedback component.
- the closed loop control is performed only based on measurements of voltage and current supplied to the electrodes.
- control of the aerosol generation can be performed using a feedback on voltage and current that is more efficient than using a direct feedback on temperature. This leads to a more stable and more accurate feedback control.
- the closed loop control comprises an electrical power feedback based on measurements of voltage and current supplied to the electrodes.
- the electrical power value can be determined from the voltage and current measurements by a controller or directly by a measuring unit.
- the power input in the closed loop ranges from 5W to 80W.
- This range of power is large enough to cause aerosol generation by different types, shapes and/or compositions of electrically conductive substrates.
- the closed loop control comprises feedback based on a resistance value of the electrically conductive substrate corresponding to a ratio of the measurements of voltage to the measurements of current.
- the resistance value can be determined from the voltage and current measurements by a controller or directly by a measuring unit.
- the voltage supplied to the electrodes is generated by a DC/DC converter controlled by a PWM duty cycle.
- the pulse width modulation (PWM) method is particularly advantageous to control a DC/DC converter such as a buck converter.
- the PWM duty cycle is determined from the measurements of voltage and current supplied to the electrodes.
- PWM duty cycle parameters can also be used to determine the PWM duty cycle such as a target power and/or an input voltage, as well as parameters characterizing user settings, type and composition of the electrically conductive substrate, its shape, duration of a vaping session, etc.
- the closed loop control is further based on temperature measurements of the electrically conductive substrate.
- the temperature measurements are used independently from the closed loop control.
- the temperature measurements can for example be used to carry out a safety feature. For example, when the temperature exceeds a predetermined threshold, substrate combustion may occur. In this case, the power supply may be cut to avoid combustion.
- CO emissions after a vaping session is highly reduced in comparison with a classical RMC cigarette.
- these CO emissions can be at least 80%, advantageously 90% and preferably 95% less than CO emissions for a RMC cigarette.
- CO emissions are measured at 31 mg per portion from a cigarette of type 1R6F. These emissions are thus less than 6,2 mg, advantageously 3,1 mg and preferably 1,55 mg when the substrate is not combusted.
- Another object of the present invention is to provide a power supply control system of an aerosol generating device comprising at least a pair of electrodes and a heating space for receiving an aerosol generating article, the electrodes being arranged opposite to each other to sandwich an electrically conductive substrate of the aerosol generating article when it is received in the heating space; wherein the control system is configured to perform a closed loop control based on measurements of both voltage and current supplied to the electrodes, to produce aerosol from the electrically conductive substrate without combustion.
- Another object of the present invention is to provide an aerosol generating system, comprising:
- the electrically conductive substrate has a parallelepiped shape and its dimensions are chosen within following ranges: length comprised between 10 and 30 mm, preferably between 15 and 25 mm, width comprised between 5 and 20 mm, preferably 10 and 15mm, thickness comprised between 0,25 and 3mm, preferably between 0,5 and 2 mm.
- the electrically conductive substrate can form a flat shape which is particularly advantageous for a fast and efficient aerosol generation during the whole vaping session.
- the electrodes are arranged to be in direct or indirect contact with wide sides of the electrically conductive substrate.
- the electrically conductive substrate of the aerosol generating article comprises tobacco.
- the tobacco can for example be compressed and mixed with any other material used to enhance vapor generation and/or taste such as water, glycerin, propylene glycol (PG), flavors, etc.
- the electrically conductive substrate further includes an electrically conductive material, such as charcoal.
- FIG. 1 shows schematically an example of an aerosol generating system 100 according to the invention.
- the aerosol generating system 100 comprises an aerosol generating device 70 and an aerosol generating article 50 configured to operate with the aerosol generating device 70.
- the aerosol generating device 70 comprises a heating space 62 for receiving at least a part of the aerosol generating article 50, and a first and a second electrodes 65, 66 arranged opposite to each other to sandwich the received part of the aerosol generating article 50 inside the heating space 62.
- the heating space 62 defines a cavity delimited by opposite lateral walls 63, 64 and a bottom wall 69.
- the electrodes 65, 66 form at least partially the opposite lateral walls 63, 64 of the cavity.
- the heating space 62 is for example configured to receive the aerosol generating article 50 inserted along a direction parallel to the electrodes 65, 66, through an opening opposite to the bottom wall 69.
- the aerosol generating device 70 further comprises a control system 49 configured to control power supply to the electrodes 65, 66 according to a control method explained in further details below.
- the control system 49 connects electrically the electrodes 65, 66 to a power source such as a battery (not shown) and controls voltage applied to these electrodes 65, 66 as it will be explained in further details below.
- the aerosol generating article 50 comprises an electrically conductive substrate 53 designed to be received in the heating space 62 and sandwiched between the electrodes 65, 66 as explained above.
- the aerosol generating article 50 can further comprise a mouthpiece part extending the electrically conductive substrate 53 and designed to be in contact with a user's mouth during a vaping session or received inside a separate mouthpiece.
- the mouthpiece can be provided with the aerosol generating device 70.
- the mouthpiece part of the aerosol generating article 50 can for example comprise filtering and/or cooling means configured to filter and/or cool aerosol produced from the electrically conductive substrate 53.
- the aerosol generating article 50 may further comprise a wrapper wrapping the electrically conductive substrate 53 together with the mouthpiece part.
- a wrapper may wrap only the electrically conductive substrate 53.
- the wrapper may be at least partially made from an electrically conductive material, such as aluminum or carbon sheet, to allow conduction of electrical current between the electrodes 65, 66 through the electrically conductive substrate 53.
- the electrically conductive substrate 53 is for example flat-shaped.
- it may have a cuboid or parallelepiped shape having a thickness (dimension intending to extend between the electrodes 65, 66) at least 5 times, advantageously 10 times smaller than its length (dimension intending to extend along the insertion direction into the heating space 62) and its width.
- the dimensions of the electrically conductive substrate 53 may be within the following ranges: length comprised between 15 mm and 20 mm, for example 18mm, width comprised between 10 mm and 15 mm, for example 12mm, thickness comprised between 0,5 mm and 3 mm, for example 1 mm.
- the electrically conductive substrate 53 comprises a vaporizable material mixed with an electrically conductive material, such as charcoal, to conduct electrical current and heat the vaporizable material to form aerosol.
- the vaporizable material may comprise tobacco, for example compressed tobacco, and may further comprise any other material used to enhance vapor generation and/or taste such as water, glycerin, PG, flavors, etc. These elements can be bonded together by one or several binders.
- the proportion of the elements composing the electrically conductive substrate 53 is adapted to ensure aerosol generation through conduction of an electrical current through the substrate 53 by means of the electrodes and the electrically conductive material contained in the electrically conductive substrate.
- the proportion of the above-cited elements can be comprised withing the following ranges: TOBACCO between 20% and 30% WATER between 25% and 35% GLYCERIN between 10% and 20% CHARCOAL between 10% and 20% PG between 5% and 15% BINDER between 0,5% and 1,5%
- composition of the electrically conductive substrate 53 may be determined according to any one of the examples disclosed in WO 2022189452 A1 .
- the control system 49 comprises a controller 51, a DC/DC converter 52 and a measuring unit 54.
- the DC/DC converter 52 is configured to supply the electrodes 65, 66 with electrical power delivered by the battery, according to commands provided by the controller 51.
- PWM pulse width modulation
- the DC/DC converter 52 can be implemented at least partially or entirely by software.
- the measuring unit 54 is configured to measure current and voltage passing through the electrically conductive substrate 53 and to provide these measurements to the controller 51.
- the measuring unit 54 may comprise for this purpose voltage and current sensors arranged in contact with the electrically conductive substrate 53.
- the sensors are arranged in contact with the electrodes 65, 66.
- the measuring unit 54 further comprises a temperature sensor arranged adjacent to the electrically conductive substrate 53 and able to provide the controller 51 with temperature measurements representing an average temperature of the electrically conductive substrate 53.
- the controller 51 is for example a microcontroller configured to process the measurements provided by measuring unit 54 to generate commands to the DC/DC convertor 52. As mentioned above, these commands may correspond to a PWM duty cycle.
- the controller 51 may also carry out other functionalities of the aerosol generating device 70 such as setting user options, monitoring and charging of the battery, etc.
- the control method carried out by the control system 49 is explained below in reference to Figure 3 .
- the control method is intended to control power supply to the electrodes 65, 66 to allow internal heating of the electrically conductive substrate 53 through conduction of an electrical current by means of the electrically conductive material contained therein and between the electrodes.
- the generated heat causes aerosol generation by the electrically conductive substrate 53 without combusting it.
- the control method performs a closed loop control based on measurements of both voltage U out and current I out supplied to the electrodes 65, 66.
- the measuring unit 54 provides to the controller 51 measurements of voltage U out and current I out supplied to the electrodes 65, 66. These measurements can be determined further to one or several samplings. According to some embodiments, the number of samplings can be adapted based on the type of the vaporizable material and/or conductive material used in the substrate 53, and/or size and shape of the substrate 53. In some embodiments, the number of samplings is defined by the controller 51. In the further description, the measurements of voltage U out and current I out used for further processing are denoted as feedback current I t-1 and feedback voltage U t-1 . In case of several samplings, each feedback value can for example be determined as an averaged value of the corresponding samplings.
- the controller 51 determines a PWM duty cycle for controlling the DC/DC converter 52, using the feedback current I t-1 and feedback voltage U t-1 , as well as a target power P set and an input voltage U in .
- the input voltage U in corresponds to the voltage provided by the battery.
- the target power P set can correspond to a predetermined value which is memorized by the controller 51.
- the target power P set is determined by the controller 51 once or before each vaping session or during a vaping session. This target power P set can be determined based on various parameters, as for example user settings, type and composition of the electrically conductive substrate 53, its shape, duration of a vaping session, etc.
- a more complex process can be used by the controller 51 to determine the PWM duty cycle. Such a process in schematically shown in Figure 4 .
- the controller 51 determines first a feedback power value P t-1 by multiplying the feedback current I t-1 with the feedback voltage U t-1 , and an entrance power P e by subtracting the feedback power value P t-1 from the target power P set . Then, the controller 51 performs a summing process where a monitored power Pt is obtained from the entrance power P e and a plurality of parameters KI.
- the parameters KI are coefficient of the integral part and can be set to constant values. For example, all parameters KI can be set to a same constant value, for example 0,5.
- the controller 51 uses both monitored power Pt and feedback resistance R t-1 to determine the PWM duty cycle D. Particularly, as shown in Figure 4 , other voltage values representing voltage through some components of the control system 49 can be used for this purpose.
- the feedback resistance R t-1 is correlated with temperature measurements acquired by the measuring unit 54.
- a more accurate value characterizing the resistance of the electrically conductive substrate 53 can be obtained.
- the correlation can be performed using for example a relationship between the resistance of the electrically conductive substrate 53 and its temperature. Such a relationship can for example be determined empirically.
- the temperature measurements are used independently from the closed loop control.
- the temperature measurements can for example be used to carry out a safety feature.
- Figure 5 shows an example of a relationship between the resistance of the electrically conductive substrate 53 and its temperature.
- the measured temperature expressed in Celsius degrees
- the resistance of the electrically conductive substrate 53 expressed in ohms
- the resistance can be derived from the substrate temperature.
- step 220 the controller 51 sends the PWM duty cycle D to the DC/DC converter 52.
- the DC/DC converter 52 generates an output voltage U out on the electrodes 65, 66, using the du the PWM duty cycle D and the input voltage U in .
- the output voltage U out is applied on the electrically conductive substrate 53.
- the temperature of the electrically conductive substrate 53 can be controlled to generate aerosol without combusting the electrically conductive substrate 53.
- Figure 6 shows an example of temperature control based on power applied over time on the electrodes 65, 66.
- the temperature expressed in Celsius degrees
- the power expressed in watts
- the power can be controlled by setting a desired set point, via the curve 31.
- the control system 49 will then try to follow this curve 31 as well as possible, as is shown by the curve 32.
Landscapes
- Control Of Resistance Heating (AREA)
Abstract
This invention relates to a method of control of supply power to the heating electrodes of an aerosol generating device comprising a heating space for receiving an electrically conductive aerosol generating pad (53) and two heating electrodes, opposite to each other so as to sandwich the heating space, wherein, the control method comprises: a step of performing a closed loop control, controlling the temperature (9) of the pad (53), based on measures of both voltage (Uout) and current (Iout) which are supplied to the heating electrodes, so as to heat the pad (53) to a temperature (9) which remains: sufficiently high so as to vapor the aerosol from the pad (53), sufficiently low so as to avoid combustion in the pad (53).
Description
- The invention relates to a control method for an aerosol generating device.
- The invention also relates to a control system and an aerosol generating system associated to such a control method. Particularly, the control method according to the invention allows operation of an aerosol generating device to generate aerosol from an aerosol generating article.
- Some aerosol generating devices deliver an inhalable aerosol by supplying electrical power using electrodes that sandwich an aerosol generating article. In such a case, the aerosol generating article comprises a substrate formed of a mixture of tobacco material with charcoal or another conductive material which makes the substate electrically conductive. Electrical current is thus applied to the substrate through at least a pair of electrodes to directly heat the tobacco material contained therein to generate the inhalable aerosol. However, it has proven difficult so far to efficiently control power delivery to the electrically conductive substrate such that organoleptic properties of the tobacco material and aerosol generation capacity are not rapidly exhausted from the substrate due to excessive or permanent heating thereof due to inertia of the electrically conductive substrate and conductive material therein.
- An aim of the present invention is to control efficiently aerosol generation in such type of aerosol generating devices.
- Therefore, the present invention provides a control method of power supply of at least a pair of electrodes comprised in an aerosol generating device, the aerosol generating device further comprising a heating space for receiving an aerosol generating article, the electrodes being arranged opposite to each other to sandwich an electrically conductive substrate of the aerosol generating article when it is received in the heating space. The control method comprises performing of a closed loop control based on measurements of both voltage and current supplied to the electrodes, to produce aerosol from the electrically conductive substrate without combustion.
- The control method according to the invention enables measurements of voltage and current passing through the electrically conductive substrate to control aerosol generation by the device. Particularly, the control method of the invention uses a closed loop control, based on feedback parameters which are voltage and current supplied to the electrically conductive substrate. Thus, temperature measurements in the substrate are no longer required to control operation of the device. Such temperature measurements in the substrate can be challenging in practice due to the need of providing temperature sensors arranged for measuring temperature of the aerosol generating substrate within the mass thereof, such as thermocouples for instance, or contactless temperature sensing arrangements to infer temperature in the aerosol generating substrate in a contactless fashion, which are not always accurate. The method according to the invention leads therefore to a resulting control which is more accurate than any existing method relying on substrate temperature measurements.
- The closed loop control can perform a temperature control of the electrically conductive substrate, based on the measurements of voltage and current supplied to the electrodes. This is an indirect temperature control, since there is no need to measure the temperature of the electrically conductive substrate itself. This indirect temperature control is based on measuring and/or on assessing one or more parameters which are representative of this temperature while being different from this temperature. The temperature control of the electrically conductive substrate is performed by heating the electrically conductive substrate in such a way that the temperature of the electrically conductive substrate will simultaneously remain sufficiently high so as to generate the aerosol from the electrically conductive substrate, typically above 50°C, and sufficiently low so as to avoid combustion in the electrically conductive substrate, typically below 350°C.
- Using the voltage and current measurements of the electrically conductive substrate over time, it is possible to determine a parameter such as its resistance, which is correlated with, thus representative of, its temperature. The control method according to the invention can thus be more accurate than a conventional method using only temperature measurements. Particularly, it is clear that the temperature measurements are necessarily related to the environment and not only to the substrate, whereas the voltage and current measurements can characterize accurately the substrate itself. Thus, a higher accuracy of control can be achieved.
- Advantageously, the heating space is designed for receiving an aerosol generating article comprising a solid electrically conductive substrate. Thus, the substrate can be sandwiched between the electrodes . The electrodes being arranged opposite to each other form a gap which is substantially constant, whatever the state of the substrate (never consumed, half consumed or exhausted for example). Additionally, the electrodes remain in contact with the substrate, whatever the state of the substrate.
- The dimensions of the electrodes may be adapted to operate efficiently with the electrically conductive substrate of an aerosol generating article. Particularly, the electrodes may cover at least 25%, advantageously 50%, preferably 75% and even more preferably 100%, of the surface area of the electrically conductive substrate of an aerosol generating article provided in the gap between the electrodes as measured in a plane parallel to electrodes contact surfaces with the aerosol generating article. The broader the contact surface between the electrodes and the aerosol generating article, the more efficient the current can be conducted through the substrate to heat it and generate an inhalable aerosol therefrom.
- Preferred embodiments comprise one or more of the following features, which can be taken separately or in combination.
- According to some embodiments, the closed loop control does not include any substrate temperature feedback component. Preferably, the closed loop control is performed only based on measurements of voltage and current supplied to the electrodes.
- Hence, control of the aerosol generation can be performed using a feedback on voltage and current that is more efficient than using a direct feedback on temperature. This leads to a more stable and more accurate feedback control.
- According to some embodiments, the closed loop control comprises an electrical power feedback based on measurements of voltage and current supplied to the electrodes.
- The electrical power value can be determined from the voltage and current measurements by a controller or directly by a measuring unit.
- Preferably, the power input in the closed loop ranges from 5W to 80W.
- This range of power is large enough to cause aerosol generation by different types, shapes and/or compositions of electrically conductive substrates.
- According to some embodiments, the closed loop control comprises feedback based on a resistance value of the electrically conductive substrate corresponding to a ratio of the measurements of voltage to the measurements of current.
- The resistance value can be determined from the voltage and current measurements by a controller or directly by a measuring unit.
- According to some embodiments, the voltage supplied to the electrodes is generated by a DC/DC converter controlled by a PWM duty cycle.
- The pulse width modulation (PWM) method is particularly advantageous to control a DC/DC converter such as a buck converter.
- According to some embodiments, the PWM duty cycle is determined from the measurements of voltage and current supplied to the electrodes.
- Other parameters can also be used to determine the PWM duty cycle such as a target power and/or an input voltage, as well as parameters characterizing user settings, type and composition of the electrically conductive substrate, its shape, duration of a vaping session, etc.
- According to some embodiments, the closed loop control is further based on temperature measurements of the electrically conductive substrate.
- These measurements can be used to be then correlated with the calculated resistance of the electrically conductive substrate to further adjust the resistance value.
- According to some embodiments, the temperature measurements are used independently from the closed loop control. The temperature measurements can for example be used to carry out a safety feature. For example, when the temperature exceeds a predetermined threshold, substrate combustion may occur. In this case, the power supply may be cut to avoid combustion.
- It may be considered that combustion is avoided, if CO emissions after a vaping session is highly reduced in comparison with a classical RMC cigarette. For example, these CO emissions can be at least 80%, advantageously 90% and preferably 95% less than CO emissions for a RMC cigarette. For example, CO emissions are measured at 31 mg per portion from a cigarette of type 1R6F. These emissions are thus less than 6,2 mg, advantageously 3,1 mg and preferably 1,55 mg when the substrate is not combusted.
- Another object of the present invention is to provide a power supply control system of an aerosol generating device comprising at least a pair of electrodes and a heating space for receiving an aerosol generating article, the electrodes being arranged opposite to each other to sandwich an electrically conductive substrate of the aerosol generating article when it is received in the heating space;
wherein the control system is configured to perform a closed loop control based on measurements of both voltage and current supplied to the electrodes, to produce aerosol from the electrically conductive substrate without combustion. - Another object of the present invention is to provide an aerosol generating system, comprising:
- an aerosol generating article comprising an electrically conductive substrate;
- an aerosol generating device comprising a heating space for receiving an aerosol generating article and a pair of electrodes arranged opposite to each other to sandwich the electrically conductive substrate of the aerosol generating article when it is received in the heating space;
- According to some embodiments, the electrically conductive substrate has a parallelepiped shape and its dimensions are chosen within following ranges: length comprised between 10 and 30 mm, preferably between 15 and 25 mm, width comprised between 5 and 20 mm, preferably 10 and 15mm, thickness comprised between 0,25 and 3mm, preferably between 0,5 and 2 mm.
- Thus, the electrically conductive substrate can form a flat shape which is particularly advantageous for a fast and efficient aerosol generation during the whole vaping session. Advantageously, the electrodes are arranged to be in direct or indirect contact with wide sides of the electrically conductive substrate.
- According to some embodiments, the electrically conductive substrate of the aerosol generating article comprises tobacco. The tobacco can for example be compressed and mixed with any other material used to enhance vapor generation and/or taste such as water, glycerin, propylene glycol (PG), flavors, etc. The electrically conductive substrate further includes an electrically conductive material, such as charcoal.
- Further features and advantages of the invention will appear from the following description of embodiments of the invention, given as non-limiting examples, with reference to the accompanying drawings listed hereunder.
-
Fig. 1 shows a schematic view of an aerosol generating system according to the invention, the aerosol generating system comprising an aerosol generating device; -
Fig. 2 shows a schematic view of a control system integrated into the aerosol generating device ofFig. 1 ; -
Fig. 3 shows a diagram explaining a control method according to the invention, the control method being carried out by the control system ofFig. 2 ; -
Fig. 4 shows an exemplary process performed by the control system ofFig. 2 according to the control method; -
Fig. 5 shows an example of relationship between temperature and resistance of an electrically conductive substrate over time; and -
Fig. 6 shows an example of temperature control based on power applied to the electrically conductive substrate. -
Figure 1 shows schematically an example of anaerosol generating system 100 according to the invention. Theaerosol generating system 100 comprises anaerosol generating device 70 and anaerosol generating article 50 configured to operate with theaerosol generating device 70. - The
aerosol generating device 70 comprises aheating space 62 for receiving at least a part of theaerosol generating article 50, and a first and asecond electrodes aerosol generating article 50 inside theheating space 62. Theheating space 62 defines a cavity delimited by oppositelateral walls bottom wall 69. Theelectrodes lateral walls heating space 62 is for example configured to receive theaerosol generating article 50 inserted along a direction parallel to theelectrodes bottom wall 69. - The
aerosol generating device 70 further comprises acontrol system 49 configured to control power supply to theelectrodes control system 49 connects electrically theelectrodes electrodes - As shown in
Figure 1 , theaerosol generating article 50 comprises an electricallyconductive substrate 53 designed to be received in theheating space 62 and sandwiched between theelectrodes aerosol generating article 50 can further comprise a mouthpiece part extending the electricallyconductive substrate 53 and designed to be in contact with a user's mouth during a vaping session or received inside a separate mouthpiece. In the latter case, the mouthpiece can be provided with theaerosol generating device 70. The mouthpiece part of theaerosol generating article 50 can for example comprise filtering and/or cooling means configured to filter and/or cool aerosol produced from the electricallyconductive substrate 53. Theaerosol generating article 50 may further comprise a wrapper wrapping the electricallyconductive substrate 53 together with the mouthpiece part. In the embodiments where theaerosol generating article 50 is provided without the mouthpiece part, a wrapper may wrap only the electricallyconductive substrate 53. In any case, the wrapper may be at least partially made from an electrically conductive material, such as aluminum or carbon sheet, to allow conduction of electrical current between theelectrodes conductive substrate 53. - The electrically
conductive substrate 53 is for example flat-shaped. For example, it may have a cuboid or parallelepiped shape having a thickness (dimension intending to extend between theelectrodes 65, 66) at least 5 times, advantageously 10 times smaller than its length (dimension intending to extend along the insertion direction into the heating space 62) and its width. In this case, the dimensions of the electricallyconductive substrate 53 may be within the following ranges: length comprised between 15 mm and 20 mm, for example 18mm, width comprised between 10 mm and 15 mm, for example 12mm, thickness comprised between 0,5 mm and 3 mm, for example 1 mm. - The electrically
conductive substrate 53 comprises a vaporizable material mixed with an electrically conductive material, such as charcoal, to conduct electrical current and heat the vaporizable material to form aerosol. The vaporizable material may comprise tobacco, for example compressed tobacco, and may further comprise any other material used to enhance vapor generation and/or taste such as water, glycerin, PG, flavors, etc. These elements can be bonded together by one or several binders. Advantageously, the proportion of the elements composing the electricallyconductive substrate 53 is adapted to ensure aerosol generation through conduction of an electrical current through thesubstrate 53 by means of the electrodes and the electrically conductive material contained in the electrically conductive substrate. As an example, the proportion of the above-cited elements can be comprised withing the following ranges:TOBACCO between 20% and 30% WATER between 25% and 35% GLYCERIN between 10% and 20% CHARCOAL between 10% and 20% PG between 5% and 15% BINDER between 0,5% and 1,5% - In a general case, the composition of the electrically
conductive substrate 53 may be determined according to any one of the examples disclosed inWO 2022189452 A1 . - In reference to
Figure 2 , thecontrol system 49 comprises acontroller 51, a DC/DC converter 52 and a measuringunit 54. The DC/DC converter 52 is configured to supply theelectrodes controller 51. For example, the DC/DC converter 52 is a buck converter designed to be controlled over a PWM (PWM = pulse width modulation) duty cycle generated by thecontroller 51. The DC/DC converter 52 can be implemented at least partially or entirely by software. The measuringunit 54 is configured to measure current and voltage passing through the electricallyconductive substrate 53 and to provide these measurements to thecontroller 51. The measuringunit 54 may comprise for this purpose voltage and current sensors arranged in contact with the electricallyconductive substrate 53. According to another embodiment, the sensors are arranged in contact with theelectrodes unit 54 further comprises a temperature sensor arranged adjacent to the electricallyconductive substrate 53 and able to provide thecontroller 51 with temperature measurements representing an average temperature of the electricallyconductive substrate 53. Thecontroller 51 is for example a microcontroller configured to process the measurements provided by measuringunit 54 to generate commands to the DC/DC convertor 52. As mentioned above, these commands may correspond to a PWM duty cycle. Thecontroller 51 may also carry out other functionalities of theaerosol generating device 70 such as setting user options, monitoring and charging of the battery, etc. - The control method carried out by the
control system 49 is explained below in reference toFigure 3 . The control method is intended to control power supply to theelectrodes conductive substrate 53 through conduction of an electrical current by means of the electrically conductive material contained therein and between the electrodes. The generated heat causes aerosol generation by the electricallyconductive substrate 53 without combusting it. For this purpose, the control method performs a closed loop control based on measurements of both voltage Uout and current Iout supplied to theelectrodes - Particularly, during
step 210, the measuringunit 54 provides to thecontroller 51 measurements of voltage Uout and current Iout supplied to theelectrodes substrate 53, and/or size and shape of thesubstrate 53. In some embodiments, the number of samplings is defined by thecontroller 51. In the further description, the measurements of voltage Uout and current Iout used for further processing are denoted as feedback current It-1 and feedback voltage Ut-1. In case of several samplings, each feedback value can for example be determined as an averaged value of the corresponding samplings. - During
step 220, thecontroller 51 determines a PWM duty cycle for controlling the DC/DC converter 52, using the feedback current It-1 and feedback voltage Ut-1, as well as a target power Pset and an input voltage Uin. The input voltage Uin corresponds to the voltage provided by the battery. The target power Pset can correspond to a predetermined value which is memorized by thecontroller 51. According to another embodiment, the target power Pset is determined by thecontroller 51 once or before each vaping session or during a vaping session. This target power Pset can be determined based on various parameters, as for example user settings, type and composition of the electricallyconductive substrate 53, its shape, duration of a vaping session, etc. -
- According to another embodiment, a more complex process can be used by the
controller 51 to determine the PWM duty cycle. Such a process in schematically shown inFigure 4 . - Referring to this
Figure 4 , thecontroller 51 determines first a feedback power value Pt-1 by multiplying the feedback current It-1 with the feedback voltage Ut-1, and an entrance power Pe by subtracting the feedback power value Pt-1 from the target power Pset. Then, thecontroller 51 performs a summing process where a monitored power Pt is obtained from the entrance power Pe and a plurality of parameters KI. The parameters KI are coefficient of the integral part and can be set to constant values. For example, all parameters KI can be set to a same constant value, for example 0,5. Then, thecontroller 51 uses both monitored power Pt and feedback resistance Rt-1 to determine the PWM duty cycle D. Particularly, as shown inFigure 4 , other voltage values representing voltage through some components of thecontrol system 49 can be used for this purpose. - According to a particular embodiment, the feedback resistance Rt-1 is correlated with temperature measurements acquired by the measuring
unit 54. In this case, a more accurate value characterizing the resistance of the electricallyconductive substrate 53 can be obtained. The correlation can be performed using for example a relationship between the resistance of the electricallyconductive substrate 53 and its temperature. Such a relationship can for example be determined empirically. - According to another embodiment, the temperature measurements are used independently from the closed loop control. The temperature measurements can for example be used to carry out a safety feature.
-
Figure 5 shows an example of a relationship between the resistance of the electricallyconductive substrate 53 and its temperature. According to this example, the measured temperature, expressed in Celsius degrees, is plotted as a function of time in seconds, by thecurve 40, and the resistance of the electricallyconductive substrate 53, expressed in ohms, is plotted as a function of time in seconds, by thecurve 41. Thus, it can be observed that the resistance can be derived from the substrate temperature. - At the end of
step 220, thecontroller 51 sends the PWM duty cycle D to the DC/DC converter 52. - During
step 230, the DC/DC converter 52 generates an output voltage Uout on theelectrodes conductive substrate 53. Thus, the temperature of the electricallyconductive substrate 53 can be controlled to generate aerosol without combusting the electricallyconductive substrate 53. -
Figure 6 shows an example of temperature control based on power applied over time on theelectrodes curve 30, and the power, expressed in watts, is plotted as a function of time in seconds, by thecurve 31 for the target power and by thecurve 32 for the effectively measured power. The power can be controlled by setting a desired set point, via thecurve 31. Thecontrol system 49 will then try to follow thiscurve 31 as well as possible, as is shown by thecurve 32. As a result, the temperature θ will change in a fairly integral way:
Claims (12)
- A control method of power supply of at least a pair of electrodes (65, 66) comprised in an aerosol generating device (70), the aerosol generating device further comprising a heating space (62) for receiving an aerosol generating article (50), the electrodes (65, 66) being arranged opposite to each other to sandwich an electrically conductive substrate (53) of the aerosol generating article (50) when it is received in the heating space (62);
wherein the control method comprises performing of a closed loop control based on measurements of both voltage (Uout) and current (Iout) supplied to the electrodes (65, 66), to produce aerosol from the electrically conductive substrate (53) without combustion. - The control method according to claim 1, wherein the closed loop control comprises determining a parameter representative of a temperature of the electrically conductive substrate (53), based on the measurements of voltage (Uout) and current (Iout) supplied to the electrodes (65, 66).
- The control method according to claim 1 or 2, wherein the closed loop control comprises an electrical power (Pt-1) feedback based on measurements of voltage (Uout) and current (Iout) supplied to the electrodes (65, 66).
- The control method according to any of the preceding claims, wherein a power (Pt) input in the closed loop ranges from 5W to 80W.
- The control method according to any of the preceding claims, wherein the closed loop control comprises feedback based on a resistance value (Rt-1) of the electrically conductive substrate (53) corresponding to a ratio of the measurements of voltage (Uout) to the measurements of current (Iout).
- The control method according to any of preceding claims, wherein the voltage (Uout) supplied to the electrodes (65, 66) is generated by a DC/DC converter (52) controlled by a PWM duty cycle.
- The control method according to claim 6, wherein the PWM duty cycle is determined from the measurements of voltage (Uout) and current (Iout) supplied to the electrodes (65, 66).
- The control method according to any of preceding claims, wherein the closed loop control is further based on temperature measurements of the electrically conductive substrate (53).
- A power supply control system (49) of an aerosol generating device (70) comprising at least a pair of electrodes (65, 66) and a heating space (62) for receiving an aerosol generating article (50), the electrodes (65, 66) being arranged opposite to each other to sandwich an electrically conductive substrate (53) of the aerosol generating article (50) when it is received in the heating space (62);
wherein the control system (49) is configured to perform a closed loop control based on measurements of both voltage (Uout) and current (Iout) supplied to the electrodes (65, 66), to produce aerosol from the electrically conductive substrate (53) without combustion. - An aerosol generating system (100) comprising:- an aerosol generating article (50) comprising an electrically conductive substrate (53);- an aerosol generating device (70) comprising a heating space (62) for receiving an aerosol generating article (50) and a pair of electrodes (65, 66) arranged opposite to each other to sandwich the electrically conductive substrate (53) of the aerosol generating article (50) when it is received in the heating space (62);wherein the aerosol generating device (70) further comprises a control system (49) according to claim 9.
- The aerosol generating system (100) according to claim 10, wherein the electrically conductive substrate (53) of the aerosol generating article (50) has a cuboid shape and its dimensions are chosen within the following ranges:o length comprised between 10 and 30 mm, preferably between 15 and 25 mm,o width comprised between 5 and 20mm, preferably 10 and 15mm,o thickness comprised between 0,25 and 3mm, preferably between 0,5 and 2mm.
- The aerosol generating system (100) according to claim 11, wherein the electrically conductive substrate (53) of the aerosol generating article (52) comprises tobacco and an electrically conductive material.
Priority Applications (1)
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EP22207142.5A EP4368049A1 (en) | 2022-11-14 | 2022-11-14 | Control method of an aerosol generating device, and associated control system and aerosol generating system |
Applications Claiming Priority (1)
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EP22207142.5A EP4368049A1 (en) | 2022-11-14 | 2022-11-14 | Control method of an aerosol generating device, and associated control system and aerosol generating system |
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EP4368049A1 true EP4368049A1 (en) | 2024-05-15 |
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EP22207142.5A Pending EP4368049A1 (en) | 2022-11-14 | 2022-11-14 | Control method of an aerosol generating device, and associated control system and aerosol generating system |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2018202403A1 (en) * | 2017-05-03 | 2018-11-08 | Philip Morris Products S.A. | A system and method for temperature control in an electrically heated aerosol-generating device |
CA3103713A1 (en) * | 2018-10-19 | 2020-04-23 | Juul Labs, Inc. | Vaporizer power system |
WO2022189452A1 (en) | 2021-03-10 | 2022-09-15 | Jt International Sa | Electrically conductive consumable |
-
2022
- 2022-11-14 EP EP22207142.5A patent/EP4368049A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2018202403A1 (en) * | 2017-05-03 | 2018-11-08 | Philip Morris Products S.A. | A system and method for temperature control in an electrically heated aerosol-generating device |
CA3103713A1 (en) * | 2018-10-19 | 2020-04-23 | Juul Labs, Inc. | Vaporizer power system |
WO2022189452A1 (en) | 2021-03-10 | 2022-09-15 | Jt International Sa | Electrically conductive consumable |
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