AEROSOL-GENERATING DEVICE WITH MEANS FOR DETECTING AT LEAST ONE OF THE INSERTION OR THE EXTRACTION OF AN AEROSOL-GENERATING ARTICLE INTO OR FROM THE DEVICE

Abstract

An aerosol-generating device to heat an aerosol-forming substrate configured to form an inhalable aerosol when heated, including: a cavity to removably receive an article including the substrate and an inductively heatable susceptor to heat the substrate; a DC power supply; an inductive heating arrangement connected to the power supply and to generate an alternating magnetic field within the cavity to inductively heat the susceptor in a heating operation when the article is received in the cavity; and control circuitry to generate power pulses for intermittently powering on the arrangement, measure for each power pulse a property of the arrangement, detect whether a change of the property has occurred as compared previous power pulses due to the susceptor becoming present within or absent from the cavity when the article is inserted or extracted, and detect insertion or extraction of the article in response to detecting of a change of the property.

Claims

1.-15. (canceled)

16. An aerosol-generating device to heat an aerosol-forming substrate configured to form an inhalable aerosol when heated, the aerosol-generating device comprising: a cavity configured to removably receive at least a portion of an aerosol-generating article, the aerosol-generating article including the aerosol-forming substrate and an inductively heatable susceptor configured to heat the aerosol-generating substrate; a DC power supply; an inductive heating arrangement connected to the DC power supply and configured to generate an alternating magnetic field within the cavity to inductively heat the inductively heatable susceptor in a heating operation when the aerosol-generating article is received in the cavity; and control circuitry configured to: generate power pulses for intermittently powering on the inductive heating arrangement, measure for each power pulse at least one property of the inductive heating arrangement, detect whether a change of the at least one property of the inductive heating arrangement has occurred as compared to one or more previous power pulses due to the inductively heatable susceptor becoming present within or absent from the cavity when the aerosol-generating article is inserted into or extracted from the cavity, and detect at least one of insertion of the aerosol-generating article into the cavity or extraction of the aerosol-generating article from the cavity in response to detecting of a change of the at least one property of the inductive heating arrangement.

17. The aerosol-generating device according to claim 16, wherein the control circuitry is further configured to disable the heating operation of the inductive heating arrangement: in response to detecting the extraction of the aerosol-generating article from the cavity during a heating operation in order to stop the heating operation, or after a previous heating operation, and until after detecting the extraction of the aerosol-generating article from the cavity in order to prevent a user from re-heating a depleted aerosol-generating article of a previous heating operation.

18. The aerosol-generating device according to claim 16, wherein the control circuitry is further configured to enable activation of the heating operation of the inductive heating arrangement: in response to detecting the extraction of the aerosol-generating article from the cavity during a heating operation, and after disabling the heating operation in order to cease disablement of the heating operation, or after a previous heating operation, and in response to detecting the extraction of the aerosol-generating article from the cavity, thus allowing a user to insert a new aerosol-generating article and to start a next heating operation.

19. The aerosol-generating device according to claim 16, wherein the control circuitry is further configured to start the heating operation of the inductive heating arrangement in response to detecting the insertion of the aerosol-generating article into the cavity.

20. The aerosol-generating device according to claim 16, wherein the control circuitry further comprises a motion sensor configured to detect movements of the aerosol-generating device.

21. The aerosol-generating device according to claim 20, wherein the control circuitry is further configured to start generating power pulses in response to detecting a movement of the aerosol-generating device.

22. The aerosol-generating device according to claim 20, wherein the control circuitry is further configured to stop generating power pulses in response to detecting for a predetermined idle time movements of the aerosol-generating device not reaching a predetermined motion threshold or in response to detecting for a predetermined idle time no movements.

23. The aerosol-generating device according to claim 16, wherein the control circuit is further configured to detect the extraction of the aerosol-generating device from a power charging unit.

24. The aerosol-generating device according to claim 23, wherein the control circuit is further configured to start generating the power pulses in response to detecting the extraction of the aerosol-generating device from the power charging unit.

25. The aerosol-generating device according to claim 16, wherein the control circuit is further configured to detect the insertion of the aerosol-generating device into a power charging unit.

26. The aerosol-generating device according to claim 25, wherein the control circuit is further configured to stop generating the power pulses in response to detecting the insertion of the aerosol-generating device into the power charging unit.

27. The aerosol-generating device according to claim 16, wherein the control circuit is further configured to start generating power pulses for detecting the extraction of the aerosol-generating article in response to detecting a stop of the heating operation of the aerosol-generating device.

28. The aerosol-generating device according to claim 16, wherein the control circuitry is further configured to stop the heating operation of the inductive heating arrangement in response to detecting the extraction of the aerosol-generating article from the cavity.

29. The aerosol-generating device according to claim 16, wherein the control circuitry comprises a measurement device configured to measure a current indicative of the at least one property of the inductive heating arrangement.

30. An aerosol-generating article for an aerosol-generating device according to claim 16, wherein the aerosol-generating article is removably receivable in the cavity of the aerosol-generating device, and wherein the aerosol-generating article comprises an aerosol-forming substrate and an inductively heatable susceptor configured to heat the aerosol-generating substrate.

Description

[0300] The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0301] FIGS. 1-2 schematically illustrate an exemplary embodiment of an aerosol-generating system according to the present invention, including an aerosol-generating device and an aerosol-generating article for use with the device;

[0302] FIG. 3 schematically illustrates the inductive heating arrangement of the aerosol-generating device according to FIGS. 1 and 2;

[0303] FIGS. 4-5 schematically illustrate operational details of the method according to the present invention; and

[0304] FIG. 6 schematically illustrates different operation modes of the aerosol-generating device according to FIG. 1, in particular the different operational modes of the method according to the present invention.

[0305] FIG. 1 and FIG. 2 schematically illustrate an exemplary embodiment of an aerosol-generating system 1 according to the present invention which is used for generating an inhalable aerosol by heating an aerosol-forming substrate. The system 1 comprises an aerosol-generating article 10 which includes the aerosol-forming substrate 21 to be heated, and an aerosol-generating device 100 for heating the substrate upon engaging the article 10 with the device 100.

[0306] As can be particularly seen in FIG. 1, the aerosol-generating article 10 has a substantially rod-shape resembling the shape of a conventional cigarette. In the present embodiment, the article 10 comprises four elements sequentially arranged in coaxial alignment: a substrate element 20 arranged at a distal end of the article 10, a support element 40 with a central air passage, an aerosol-cooling element 50, and a filter element 60 arranged at a proximal end of the article 10 which serves as a mouthpiece. The substrate element 20 comprises the aerosol-forming substrate 21 to be heated as well as a susceptor 30 which is in direct physical contact with substrate 21 and used to inductively heat the substrate 21. This will be described in more detail below. The four elements have a substantially cylindrical shape with substantially the same diameter. In addition, the four elements are circumscribed by an outer wrapper 70 such as to keep the four elements together and to maintain the desired circular cross-sectional shape of the rod-like article 10. The wrapper 70 preferably is made of paper. Further details of the article 10, in particular of the four elements, are disclosed, for example, in WO 2015/176898 A1.

[0307] The elongate aerosol-generating device 100 basically has two portions: a proximal portion 102 and a distal portion 101. In the proximal portion 102, the device 100 comprises a cavity 103 for removably receiving at least a portion of the aerosol-generating article 10. In the distal portion 101, the device 100 comprises a power source 150 and a controller 160 for powering and controlling operation of the device 100. For heating substrate, the device 100 comprises an inductive heating arrangement 110 including an induction coil 118 for generating an alternating, in particular high-frequency magnetic field within the cavity 103. In the present embodiment, the induction coil 118 is a helical coil which is arranged in the proximal portion 102 of the device such as to circumferentially surround the cylindrical receiving cavity 103. The coil 118 is arranged such that the susceptor 30 of the aerosol-generating article 10 experiences the electromagnetic field upon engaging the article 10 with the device 100. The alternating magnetic field is used to inductively heat the susceptor 30 within the aerosol-generating article 10 when the article 10 is received in the cavity 103. Thus, upon inserting the article 10 into the cavity 103 of the device 100 (see FIG. 2) and activation of the heating arrangement 110, the alternating electromagnetic field within the cavity 103 induces eddy currents and/or hysteresis losses in the susceptor 30, depending on the magnetic and electric properties of the susceptor material. As a consequence, the susceptor 30 heats up until reaching a temperature sufficient to vaporize the aerosol-forming substrate 21 surrounding the susceptor 30 within the article 10. In use of the system, when a user takes a puff, that is, when a negative pressure is applied at the filter element 60 of the article 10, air is drawn into the cavity 103 at the rim of the article insertion opening 105 of the device 100. The air flow further extends towards the distal end of the cavity 103 through a passage which is formed between the inner surface of the cylindrical cavity 103 and the outer surface of the article 10. At the distal end of the cavity 103, the air flow enters the aerosol-generating article 10 through the substrate element 20 and further passes through the support element 40, the aerosol cooling element 50 and the filter element 60 where it finally exits the article 10. In the substrate element 20, vaporized material from the aerosol-forming substrate 21 is entrained into the air flow. Subsequently, when passing through the support element 40, the cooling element 50 and the filter element 60 the air flow including the vaporized material cools down such as to form an aerosol escaping the article 10 through the filter element 60.

[0308] FIG. 3 shows further details of the inductive heating arrangement 110 used to generate an alternating magnetic field within the cavity 103. According to the present embodiment, the inductive heating arrangement 110 comprises a DC/AC inverter which is connect to the DC power source 150 shown in FIGS. 1 and 2. The DC/AC inverter includes a Class-E power amplifier which in turn includes the following components: a transistor switch 111 comprising a Field Effect Transistor T (FET), for example a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), a transistor switch supply circuit indicated by the arrow 112 for supplying the switching signal (gate-source voltage) to the transistor switch 111, and an LC load network 113 comprising a shunt capacitor C1 and a series connection of a capacitor C2 and inductor L2. The inductor L2 corresponds to the induction coil 118 shown in FIGS. 1 and 2 used to generate an alternating magnetic field within the cavity 103. In addition, there is provided a choke L1 for supplying a DC supply voltage +V_DC from to the DC power source 150. Also shown in FIG. 3 is the ohmic resistance R representing the total equivalent resistance or total resistive load 114, which—in use of the system, that is, when the article is inserted in the cavity 103 of the device 100—is the sum of the ohmic resistance of the inductor coil 118, marked as L2, and the ohmic resistance of the susceptor. Otherwise, in case no article is inserted in the cavity 103, the equivalent resistance or resistive load 114 only corresponds to the ohmic resistance of the inductor coil 118.

[0309] Further details of the inductive heating arrangement 110 according to the present embodiment, in particular with regard to its working principle, are disclosed, for example, in WO 2015/177046 A1.

[0310] For various purposes, in particular for automatically enabling or disabling the heating process and/or for preventing a user from re-heating of a depleted aerosol-generating article, it might be desirable to detect at least one of the insertion of an aerosol-generating article into the receiving cavity 103 and the extraction of an aerosol-generating article from the receiving cavity 103. For this, the aerosol-generating device according to the present embodiment may be operated in at least one of an article insertion detection mode or an article extraction detection mode.

[0311] According to the present invention, article insertion and/or extraction detection is realized via the heating arrangement 110 itself. Advantageously, this enables to avoid additional assembly space for separate sensor means. The basic idea for detecting the insertion and/or extraction of the article into or from the cavity is to detect a change of at least one property of the inductive heating arrangement due to the presence or extraction of the susceptor when an aerosol-generating article 10 is received in or extracted from the cavity 103.

[0312] In the present embodiment, it is the total resistive load 114 of the heating arrangement 110 which is used as a property of the inductive heating arrangement indicative of the presence or absence of an article 10 in the receiving cavity 103. As explained above, the value of the total equivalent resistance or total resistive load 114 depends on the presence or absence of the susceptor 30 in the vicinity of the induction coil 118. When the article is inserted in the cavity 103 of the device 100, the total equivalent resistance 118 corresponds to the sum of the ohmic resistance of the inductor coil 118 and the ohmic resistance of the susceptor 30, whereas it corresponds to the ohmic resistance of the inductor coil 118 only, when no article is received in the cavity 103.

[0313] This change of the equivalent resistance 118 may be detected via the DC current I_DC provided from the DC power source 150 to the inductive heating arrangement 110, that is, to the LC load network 113. For this, the aerosol-generating device comprises a current measurement device 140 arranged in series connection between the DC power supply 150 and the LC load network 113. Accordingly, when an aerosol-generating article 10 is inserted into the cavity 103 of the aerosol-generating device 100, the presence of the susceptor 30 increases the equivalent resistance 118 of the heating arrangement due to an increase of the resistive load 114. This in turn causes a decrease of the DC current feeding the inductive heating arrangement 110. The decrease of the DC current I_DC is detected by the current measurement device 140 which in turn may be used as a trigger signal to activate heat operation of the inductive heating arrangement 110 for heating the substrate 21.

[0314] Vice versa, when an aerosol-generating article 10 is extracted from the cavity 103, the absence of the susceptor 30 causes a decrease of the equivalent resistance 118 of the heating arrangement due to a decrease of the resistive load 114. This in turn causes an increase of the DC current feeding the inductive heating arrangement 110.

[0315] Both, the decrease as well as the increase of the DC current (ΔI_DC) may be detected by the current measurement device 140.

[0316] In order to reduce the overall power consumption when the aerosol-generating device 100 is in an article detection mode (e.g. either in an article insertion detection mode or an article extraction detection mode), the heating assembly is not operated in a continuous mode, but in a pulsed mode. For this, the aerosol-generating device 100 comprises a switch 130 that is arranged and configured to control a supply of power from the DC power supply 150 to the inductive heating arrangement 110. In the present embodiment, the switch 130 is arranged in series connection between the DC power supply 150 and the LC load network 113. During the article detection mode, the switch is intermittently opened and closed such as to generate power pulses for intermittently powering on the inductive heating arrangement 130. In contrast, during the heating mode of the aerosol-generating device 100 the switch may be permanently closed to continuously apply a DC voltage from the DC power supply to the inductive heating arrangement 110. It is also possible that the switch may be intermittently closed and opened during the heating mode of the aerosol-generating device such as to generate heating power pulses for pulsed heating of the aerosol-forming substrate. Accordingly, this mode may be denoted as pulsed heating mode.

[0317] As shown in FIG. 3, the switch 130 and the current measurement device 140 are both part of a control circuitry which also includes a microprocessor 160. The microprocessor 160 is configured to control the switch 130 used to generate power pulses for intermittently powering on the inductive heating arrangement 110, to read out the measurement device 140 for measuring the current I_DC supplied from the DC power supply to the inductive heating arrangement 110 and to control the transistor switch driver circuit 112 of the inductive heating arrangement 110. The control circuitry may be or may be art of an overall controller of the aerosol-generating device 100.

[0318] In the article insertion/extraction detection mode, the microprocessor 160 starts driving the switch 130 by closing it for a pre-determined closing time interval, thereby generating of a current pulse having a pulse duration T1 corresponding to the closing time interval. The pulse duration T1 may be in a range between 1 microsecond and 500 microseconds, in particular between 10 microseconds and 300 microseconds, preferably between 15 microseconds and 120 microseconds, most preferably between 30 microseconds to 100 microseconds. At the end of the closing time interval, the microprocessor 160 opens the switch 130 again for a pre-determined opening time interval, thereby interrupting the current passage to the heating arrangement. The opening time interval corresponds to the time interval between two consecutive power pulses, which for article detection may be in a range between 50 milliseconds and 2 seconds, in particular between 100 milliseconds and 2 seconds, preferably between 500 milliseconds and 1 second. Closing and opening of the switch 130 may occur at regular time intervals such as to generate periodic power pulses for periodically powering on the inductive heating arrangement. Thus, the sum of the closing time interval and the opening time interval, or the sum of the pulse duration and the time interval between two consecutive power pulses corresponds to the periodicity of the pulse series. In general, the time interval between two consecutive probe power pulses T2 should be selected such as to balance the effect of energy depletion and user experience performance. The pulse duration T1 should be kept as minimal as possible but such to provide a reliable measurement of current pulse.

[0319] FIG. 4 is a graph showing the evolution of current pulses I_DC with time t according to an exemplary embodiment of the method of the present invention. According to this embodiment, a series of current pulses is generated with a pulse duration T1 of 100 microseconds and a time interval between two consecutive power pulses T2 of 1 second. It will be appreciated that these values are only exemplary and may change.

[0320] As long as no aerosol-generating article has been inserted, the current measuring device 140 measures for each pulse a current having a value I_NA (where the “NA” stands for “no article”). As explained, the measured value I_NA depends on the ohmic load 114, which equals the ohmic resistance of the inductor L2. In contrast, when user inserts an aerosol-generating article into the cavity 103, the ohmic load 114 is increased, since now the ohmic load equals the ohmic resistance of the inductor L2 and the ohmic resistance of the susceptor 21. Due to the increase of the ohmic load the current absorbed by heating assembly decreases. Accordingly, the current measuring device 140 measures a current pulse having a value of I_A (where the “A” stands for “article inserted”) which is lower than I_NA. The difference ΔI_DC between I_NA and I_A is recorded by the microcontroller 160 which triggers the start of the heating mode.

[0321] The article insertion detection mode may be triggered, for example, by extracting the aerosol-generating device 100 from a power charging unit. For this, the aerosol-generating device may be configured to detect the extraction of the device from a power charging unit.

[0322] While FIG. 4 shows the article insertion detection mode only, FIG. 5 shows both, the evolution of current pulses I_DC during the article insertion detection mode (see left half of FIG. 5) as well as during the article extraction detection mode (see right half of FIG. 5). For the evolution of current pulses I_DC during the article insertion detection mode, reference is made to the above description of FIG. 4. The evolution of current pulses I_DC during the article extraction detection mode is reversed. That is, during the article extraction detection mode the current measuring device 140 measures for each pulse a current having a value of I_A as long as an aerosol-generating article is still received in the cavity 103. As soon as the article is extracted from the cavity, the ohmic load 114 is decreased which causes the current absorbed by the heating assembly to increase. Accordingly, the current measuring device 140 measures a current pulse having a value I_NA. The difference ΔI_DC between I_A and I_NA is also recorded by the microcontroller 160, thus indicating the extraction of the article from the cavity.

[0323] FIG. 6 shows an exemplary embedment of the method according to the present invention for operating an aerosol-generating device, in particular an aerosol-generating device 100 according to FIG. 1. In particular, FIG. 6 schematically illustrates flow diagram representing the different operational modes of the aerosol-generating device according to the present invention.

[0324] Typically, a user starts a new user experience by extracting the aerosol-generating device 100 from a power charging unit used for charging the DC power supply 150 of the device 100. This step is indicated by arrow 1150. During charging as indicated by box 1100, the device 100 is either off or in a standby mode. Advantageously, extraction 1150 of the aerosol-generating device 100 from power charging unit may be used trigger an article insertion detection mode—indicated by box 1200—for detecting the insertion of the aerosol-generating article into the cavity of the aerosol-generating device. In the article insertion detection mode 1200, a sequence of probe power pulses is generated to intermittently power on the inductive heating arrangement. At the same time, a property of the inductive heating arrangement—preferably the total resistive load of the heating arrangement—is measured for each pulse and detected whether a change of that property has occurred as compared to previous pulses, thus indicating the insertion of an aerosol-generating article into the cavity. In response to detecting such a change, the article insertion detection mode 1200 is stopped, followed by activating a heating operation of the inductive heating arrangement—as indicated by box 1300—in order to operate the device in a heating mode for heating the aerosol-forming substrate. Preferably, the detection of the insertion of an article triggers the start of the heating operation 1300, as indicate by arrow 1250. The heating operation may comprise different heating steps, such as a pre-heating step and a main heating step.

[0325] The heating operation 1300 may stop after a pre-determined number of puffs or a pre-determined heating time has elapsed. Alternatively, the heating operation 1300 may be stopped manually, for example by receiving a user input from a switch.

[0326] Once the heating operation 1300 has stopped, the device is operated in an article extraction detection mode, as indicate by box 1400. Preferably, the article extraction detection mode 1400 starts in response to a stop of the heating operation 1300, in particular in response to detecting a stop of the heating operation 1300. In the article extraction detection mode 1400—like in the article insertion detection mode 1200—a sequence of probe power pulses is generated to intermittently power on the inductive heating arrangement. At the same time, a property of the inductive heating arrangement—preferably again the total resistive load of the heating arrangement—is measured for each pulse and detected whether a change of that property has occurred as compared to previous pulses, thus indicating the extraction of an aerosol-generating article from the cavity.

[0327] During the article extraction detection mode 1400, activation of a new heating operation is disabled in order to prevent a user from re-heating a depleted aerosol-generating article of a previous heating operation. As soon as the extraction of the aerosol-generating article is detected, as indicated by arrow 1450, the article extraction detection mode 1400 is stopped and activation of a new heating operation is enabled again, allowing a user to insert a new aerosol-generating article and to start the next heating operation. Accordingly, a next article insertion detection mode 1200 may be started in response to detecting the extraction of an aerosol-generating article.

[0328] In order to reduce the power consumption and, thus, to increase the overall operation time of the device addition, the device may be operated in a stand-by mode—indicated by box 1500—prior to operating the device in the (next) article insertion detection mode, in particular after the article extraction detection mode 1400 is stopped, that is, in response to detecting the extraction of an aerosol-generating article of a previous user experience. In the stand-by mode, the device is monitored for movements using a movement sensor, for example an accelerometer. In response to detecting movements of the device or movements of the device reaching or exceeding a pre-determined motion threshold, the (next) article insertion detection mode is started, as indicated by arrow 1550 in FIG. 6. Preferably, the device is continuously monitored for movements until movements of the device or movements of the device reaching or exceeding a pre-determined motion threshold are detected.

[0329] In order to reduce the power consumption, the device may be operated in an idle state monitoring mode during at least one of operating the device in the article extraction detection mode or operating the device in the article insertion detection mode. In the idle state monitoring mode, like in the stand-by mode, the device is monitored for movements using a movement sensor. In response to detecting for a predetermined idle time movements of the device not reaching a pre-determined motion threshold or even no movements, operation of the device in the article extraction detection mode or in the article insertion detection mode, respectively.

[0330] In another configuration of the idle state monitoring mode, detection is not stopped in response to detecting for a predetermined idle time movements of the device not reaching a pre-determined motion threshold or even no movements. Instead, the number of probe power pulses per time unit may be reduced, for example, by a factor of two or three.

[0331] In yet another configuration of the idle state monitoring mode,

[0332] According to another alternative configuration, the number of probe power pulses per time unit may be first reduced in response to detecting for a predetermined first idle time movements of the device not reaching a pre-determined motion threshold or even no movements. In FIG. 6, this is indicated by box 1600 for the article extraction detection mode, and by box 1700 for the article insertion detection mode. Only subsequently, the generation of probe power pulses may be stopped in response to detecting for a predetermined second idle time starting after the first idle time movements of the device not reaching the pre-determined motion threshold or even no movements.

[0333] In any of these configurations, once the generation of probe power pulses has been stopped due to the device being in an idle state, as indicated by arrows 1650 and 1750, the device may switch into the stand-by mode 1500 in order to monitor the device for movements and subsequently—in response to detecting an appropriate movement—to (re)start operation of the device in the article extraction detection mode 1400 or in the article insertion detection mode 1200, respectively, as indicated by arrows 1550.

[0334] The stand-by mode may be stopped in response to detecting the inserting of the device into the charging unit.

[0335] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A±5 percent A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.