Aerosol generating device

Abstract

The present application discloses an aerosol generating device, comprising: a liquid storage unit for storing a liquid capable of generating an aerosol; a heating element for heating the liquid; a liquid transfer unit for transferring the liquid stored in the liquid storage unit to the heating element; a power supply for providing power to the heating element; and a circuit configured to determine, after a preset time point after the heating element starts heating, whether the liquid stored in the liquid storage unit has been reduced to a threshold value; wherein the preset time point is determined based on the moment when the resistance change rate of the heating element decreases to 1% to 30% of the resistance change rate of the heating element when heating is started. After the resistance change rate of the heating element decreases to 1% to 30%, the present application can accurately determine whether a dry burn occurs in the second half of each puff, thereby avoiding the generation of unwanted harmful gases and burnt odors, preventing damage to the user's health, and improving the user's puffing experience.

Description

Technical Field

[0001] The present application relates to the technical field of smoking articles, and in particular to an aerosol generating device. Background Art

[0002] One type of aerosol generating device generates smoke for users to inhale by heating tobacco oil. It generally consists of two parts: an atomizer and a battery assembly. The atomizer stores tobacco oil and is equipped with an atomizer core for heating the tobacco oil. The battery assembly can power the atomizer core to generate heat and generate high temperature to heat the tobacco oil.

[0003] Patent document with application publication number CN103338665A discloses an electrically operated aerosol generating system. Between 0 seconds and 0.2 seconds of each puff, since the slope of the temperature curve increases as the liquid storage portion becomes empty, the linear characteristics of the temperature rise rate in the "emptying" region between X1 and X2 puffs can be used to measure the amount of aerosol-forming substrate remaining in the liquid storage portion, thereby making it possible to judge changes in temperature levels more quickly and helping to reduce the risk of aerosol characteristics becoming poor.

[0004] The problem with this method is that the heater temperature rises sharply between 0 seconds and 0.2 seconds of each puff, and this period is very short and the temperature data fluctuates greatly. Therefore, the slope method cannot accurately determine whether the amount of the liquid storage portion has decreased to the threshold during this period. Summary of the Invention

[0005] The present application provides an aerosol generating device to solve the problem of how to accurately identify a dry burn of the aerosol generating device when the aerosol generating device is being inhaled.

[0006] The present application provides an aerosol generating device, comprising:

[0007] a liquid storage unit, used for storing a liquid capable of generating an aerosol;

[0008] a heating element for heating the liquid;

[0009] a liquid transfer unit for transferring the liquid stored in the liquid storage unit to the heating element;

[0010] a power source for providing power to the heating element;

[0011] a circuit configured to determine whether the liquid stored in the liquid storage unit has decreased to a threshold value after a preset time point after the heating element starts heating;

[0012] The preset time point is determined according to the moment when the resistance change rate of the heating element decreases to 1% to 30% of the resistance change rate of the heating element when the heating is started.

[0013] The aerosol generating device experiences dry burning most of the time during the second half of each puff. After the resistance change rate of the heating element decreases to 1% to 30%, it is advantageously possible to accurately determine whether dry burning occurs during the second half of each puff, thereby avoiding the generation of unwanted harmful gases and burnt odors, preventing damage to the user's health, and improving the user's puffing experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The implementation of the objectives, functional features, and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. One or more embodiments are exemplarily illustrated by the figures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings are not intended to be proportional.

[0015] Figure 1 Schematic diagram of an aerosol generating device provided in an embodiment of the present application;

[0016] Figure 2 Schematic diagram of a resistance detection circuit in an aerosol generating device provided in an embodiment of the present application;

[0017] Figure 3 This is a schematic diagram of another resistance detection circuit in the aerosol generating device provided in an embodiment of the present application;

[0018] Figure 4 Schematic diagram of the control process of the aerosol generating device provided in an embodiment of the present application;

[0019] Figure 5 Schematic diagram of the control process of the aerosol generating device provided in the embodiment of the present application;

[0020] Figure 6 is another schematic diagram of a control process of an aerosol generating device provided in an embodiment of the present application;

[0021] Figure 7 This is another curve diagram of the control process of the aerosol generating device provided in the embodiment of the present application. DETAILED DESCRIPTION

[0022] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In order to facilitate understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "left", "right", "inside", "outside" and similar expressions used in this specification are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the relevant listed items.

[0024] Figure 1 Schematic diagram of an aerosol generating device provided in an embodiment of the present application.

[0025] like Figure 1 As shown, the aerosol generating device comprises a mouthpiece 11 , a liquid storage unit 12 , a liquid delivery unit 13 , a heating element 14 , a circuit 15 , a power source 16 and a sensor 17 .

[0026] The mouthpiece 11 is used for the user to inhale the aerosol generated by heating.

[0027] Liquid storage unit 12 is used to store the liquid that can generate aerosol.Liquid state can be for comprising the liquid that contains the tobacco material that contains volatile tobacco flavor component, can also be for comprising the liquid of non-tobacco material.For example, liquid can comprise water, solvent, ethanol, plant extract, spices, flavoring agent or vitamin mixture.Spice can comprise menthol, peppermint, spearmint oil, various fruity fragrance components etc., but is not limited to this.Flavoring agent can comprise the composition that can provide multiple fragrance or local flavor to the user.Vitamin mixture can be for being mixed with at least a material in vitamin A, vitamin B, vitamin C and the vitamin E, but is not limited to this.In addition, liquid can comprise the aerosol forming agent as glycerol and propylene glycol.

[0028] The liquid transfer unit 13 can transfer the liquid stored in the liquid storage unit 12 to the heating element 14. For example, the liquid transfer unit 13 can be made of cotton fiber, ceramic fiber, glass fiber, etc., but is not limited thereto.

[0029] The heating element 14 is a component used to heat the liquid transferred through the liquid transfer unit 13. For example, the heating element 14 can be a metal wire, a metal plate, a ceramic heater, etc., but is not limited thereto. Furthermore, the heating element 14 can be formed of a conductive heating wire, such as a nickel-chromium wire, and can be arranged to be wound around the liquid transfer unit 13. The heating element 14 can be heated by supplying an electric current and transfers heat to the liquid in contact with the heating element 14 to heat the liquid and thereby generate an aerosol. In this example, the heating element 14 is made of a material having a characteristic temperature coefficient of resistance, such as 316 stainless steel, titanium, nickel, or a nickel-chromium alloy.

[0030] The circuit 15 can control the overall operation of the aerosol-generating device. Specifically, the circuit 15 controls not only the operation of the power supply 16 and the heating element 14, but also the operation of other components in the aerosol-generating device. Furthermore, the circuit 15 can determine whether the aerosol-generating device is operational by checking the status of its components.

[0031] Circuit 15 includes at least one processor. The processor may include a logic gate array, or may include a combination of a general-purpose microprocessor and a memory storing programs executable in the microprocessor. In addition, those skilled in the art will appreciate that circuit 15 may include another type of hardware.

[0032] The power supply 16 provides power for operating the aerosol generating device. For example, the power supply 16 can provide power to heat the heating element 14 and can provide power required to operate the circuit 15. In addition, the power supply 16 can provide power required to operate sensors, motors, etc. provided in the aerosol generating device.

[0033] The power source 16 may be, but is not limited to, a lithium iron phosphate (LiFePO4) battery. For example, the power source 16 may be a lithium cobalt oxide (LiCoO2) battery or a lithium titanate battery. The power source 16 may be a rechargeable battery or a disposable battery.

[0034] The sensor 17 is used to detect the user's puffing action and generate a corresponding electrical signal, so that the circuit 15 controls the operation of the power supply 16, the heating element 14, etc. according to the electrical signal. The sensor 17 can be a common pressure sensor, a pressure difference sensor, an airflow sensor, etc.

[0035] An air inlet is provided at a position adjacent to the sensor 17 of the aerosol generating device. When the aerosol generating device is inhaled, air enters through the air inlet, flows through the sensor 17, power supply 16, circuit 15, heating element 14, etc., and then flows out through the nozzle 11. The dotted arrow in the figure roughly shows the airflow path.

[0036] It should be noted that Figure 1Only the components relevant to this embodiment are shown. A person skilled in the art will appreciate that the aerosol generating device may further include components other than Figure 1 Other common components other than those shown.

[0037] Figure 2 This is a schematic diagram of a resistance detection circuit provided in an embodiment of the present application.

[0038] like Figure 2 As shown, Ri is a heating element 14, and R1 is a sampling resistor. The heating element 14 and the sampling resistor R1 are connected in series between a power supply 16 (denoted as VBAT in the figure) and the push-pull output port 10 of the processor. The processor's first voltage sampling port ADC1 is connected to one end of the sampling resistor R1, and the processor's second voltage sampling port ADC2 is connected to the other end of the sampling resistor R1. Compared to the prior art, the switch connected in series with the sampling resistor R1 and its associated resistor (with a relatively large resistance) are omitted.

[0039] When the resistance value of the heating element 14 needs to be detected, the push-pull output port IO outputs a low level, and then the processor obtains the voltage V through the first voltage sampling port ADC1. ADC1 , the voltage V is obtained through the second voltage sampling port ADC2 ADC2 , and then the resistance of the heating element 14 can be obtained by the following formula:

[0040] Ri=(V BAT -V ADC2 )×R1 / (V ADC2 -V ADC1 )

[0041] Figure 3 This is another resistance detection circuit schematic provided in an embodiment of the present application.

[0042] like Figure 3 As shown, the circuit 15 includes a switch tube Q8, a heating element 14 (connected to the D+ and D- terminals in the figure), and a sampling resistor R4, which are sequentially connected in series between the positive and negative poles of the power supply 16 (shown as VBAT in the figure), and U1 is a sensor 17. The control end of the switch tube Q8 is connected to the control port OUT_CTR of the processor, and the switching tube Q8 can be controlled to be turned on or off through the control port OUT_CTR. The first voltage sampling port AT-DET of the processor is set between the switch tube Q8 and the heating element 14, and the second voltage sampling port OUT1-ADC of the processor is set between the heating element 14 and the sampling resistor R4. Compared with the prior art, the switch tube and its associated resistor (with a larger resistance) connected in series with the sampling resistor R1 are also omitted, and the main circuit is used to realize the detection of the resistance value.

[0043] Specifically, when the sensor 17 detects the suction, the processor controls the switch tube Q8 to be turned on through the control port OUT_CTR, and then the processor obtains the voltage V through the first voltage sampling port AT-DET. AT-DET , the voltage V is obtained through the second voltage sampling port OUT1-ADC OUT1-ADC , and then the resistance of the heating element 14 can be obtained by the following formula:

[0044] Ri=V AT-DET ×R4 / V OUT1-ADC -R4

[0045] based on Figure 2-Figure 3 The resistance detection circuit, circuit 15, is configured to determine whether the liquid stored in the liquid storage unit 12 has decreased to a threshold value after a preset time point after the heating element 14 starts heating;

[0046] The preset time point is determined according to the moment when the resistance change rate of the heating element 14 decreases to 1% to 30% of the resistance change rate of the heating element 14 when the heating is started.

[0047] In this example, after the resistance change rate of the heating element decreases to 1% to 30%, it is determined whether the liquid stored in the liquid storage unit 12 has been reduced to the threshold value. This can avoid the problem of inaccurate judgment caused by large fluctuations in the previous temperature (or real-time resistance) data. Preferably, the judgment can be made after the resistance change rate of the heating element decreases to 5% to 30%; more preferably, the judgment can be made after the resistance change rate of the heating element decreases to 5% to 25%; more preferably, the judgment can be made after the resistance change rate of the heating element decreases to 5% to 20%; more preferably, the judgment can be made after the resistance change rate of the heating element decreases to 10% to 20%.

[0048] In one example, the preset time point is after 600ms (including 600ms); preferably, the preset time point is after 800ms (including 800ms); further preferably, the preset time point is after 1000ms (including 1000ms).

[0049] In one example, the circuit 15 is configured to determine whether the liquid stored in the liquid storage unit 12 has decreased to a threshold value based on the difference between the resistance change rate of the heating element 14 and a preset resistance change rate.

[0050] Specifically, if the resistance change rate of the heating element 14 is greater than the preset resistance change rate, it is determined that the liquid stored in the liquid storage unit 12 has decreased to a threshold value.

[0051] Furthermore, the circuit 15 is configured to determine whether the liquid stored in the liquid storage unit 12 has decreased to a threshold value based on the number of times the resistance change rate of the heating element 14 continuously exceeds a preset resistance change rate.

[0052] Specifically, if the resistance change rate of the heating element 14 is continuously greater than the preset resistance change rate for more than a first preset number of times, it is determined that the liquid stored in the liquid storage unit 12 has decreased to a threshold value.

[0053] In this example, the circuit 15 is configured to store the real-time resistance value of the heating element 14 in a preset buffer and calculate the resistance change rate of the heating element 14:

[0054] K j =(R N+j -R 0+j ) / R 0+j , where K j is the resistance change rate of the heating element 14, N is the length of the preset buffer zone, and j is a natural number.

[0055] For example: assuming N=5, when j=0, K0=(R5-R0) / R0; when j=1, K1=(R6-R1) / R1; when j=2, K2=(R7-R2) / R2; when j=3, K3=(R8-R3) / R3; and so on.

[0056] In this example, there is generally liquid in the first half of each pumping, but no liquid in the second half (for example, insufficient liquid supply), which causes the resistance change rate of the heating element 14 to be continuously greater than the preset resistance change rate for more than a first preset number of times.

[0057] In one example, the circuit 15 is configured to determine whether the liquid stored in the liquid storage unit 12 has decreased to a threshold value based on the real-time resistance value of the heating element 14 and the over-temperature threshold value.

[0058] In this example, the circuit 15 is configured to:

[0059] If the real-time resistance of the heating element 14 exceeds the over-temperature threshold, the power output to the heating element 14 is reduced in order to maintain the temperature of the heating element 14 at a preset temperature, or to maintain the real-time resistance of the heating element 14 at a resistance value corresponding to the preset temperature;

[0060] If the power output to the heating element 14 is reduced to the preset power, but the temperature of the heating element 14 is still not successfully maintained at the preset temperature, or the real-time resistance of the heating element 14 is still not successfully maintained at the resistance value corresponding to the preset temperature, it is determined that the liquid stored in the liquid storage unit 12 has been reduced to a threshold value.

[0061] The over-temperature threshold is the resistance value corresponding to the maximum atomization temperature that the aerosol generating device can accept during puffing. The over-temperature threshold can be a default threshold or a dynamic threshold, determined based on the material of the heating element 14. The preset temperature is the atomization temperature that the aerosol generating device is expected to maintain during puffing to achieve optimal atomization effect.

[0062] Failure to successfully maintain the temperature of the heating element 14 at the preset temperature, or failure to successfully maintain the real-time resistance of the heating element 14 at the resistance value corresponding to the preset temperature, means that during the period when the power output to the heating element 14 is reduced to the preset power, the real-time resistance or temperature of the heating element 14 continues to rise; specifically, the real-time resistance of the heating element 14 exceeds the resistance value corresponding to the preset temperature, or the temperature of the heating element 14 exceeds the preset temperature.

[0063] In this example, continuous suction generally causes the temperature of the heating element 14 to be too high. Even if the liquid supply is normal, the temperature of the heating element 14 cannot be successfully maintained at the preset temperature, or the real-time resistance of the heating element 14 cannot be successfully maintained at the resistance value corresponding to the preset temperature.

[0064] In one example, the circuit 15 is configured to:

[0065] Before a preset time point, obtaining an initial resistance value and M real-time resistance values ​​of the heating element 14;

[0066] Calculating the difference between each real-time resistance value and the initial resistance value;

[0067] Compare the M difference values ​​with the M preset difference values ​​one by one;

[0068] If the difference value exceeds the preset difference value continuously for more than a second preset number of times, it is determined that the liquid in the liquid storage unit 12 has been reduced to a threshold value.

[0069] In this example, the difference value exceeds the preset difference value more than a second preset number of times, typically due to the absence of liquid or very low liquid content in the liquid storage unit 12. Therefore, N different values ​​are set to identify the difference. The N preset difference values ​​are empirical values ​​or test values, for example, obtained through extensive testing and integration of test data. N is a positive integer. Generally, N is between 8 and 16, preferably between 8 and 14, and more preferably between 8 and 12. The detection interval of the N real-time resistance values ​​is between 40 ms and 100 ms, preferably between 40 ms and 80 ms.

[0070] In one example, the circuit 15 is configured to:

[0071] Before a preset time point, obtaining a real-time resistance value of the heating element;

[0072] comparing the real-time resistance value of the heating element with a preset maximum threshold;

[0073] If the real-time resistance value of the heating element is greater than a preset maximum threshold value, it is determined that the liquid stored in the liquid storage unit has decreased to a threshold value.

[0074] In this example, if the liquid storage unit 12 contains no liquid or very little liquid, the real-time resistance of the heating element 14 can be compared with a preset maximum threshold to determine whether the liquid stored in the liquid storage unit 12 has decreased to a threshold. Generally, the preset maximum threshold is greater than the over-temperature threshold.

[0075] It should be noted that in the above example, if the liquid in the liquid storage unit 12 has decreased to a threshold value, the power output to the heating element 14 is stopped. This avoids the generation of unwanted harmful gases and burnt odors, prevents damage to the user's health, and improves the user's smoking experience.

[0076] Figure 4 This is a schematic diagram of the control process of the aerosol generating device provided in the embodiment of the present application. The control process is described with reference to a specific case, specifically including:

[0077] Step S21, starting the aerosol generating device;

[0078] Step S22: Obtain the initial resistance value and 10 real-time resistance values ​​of the heating element 14; for example, the initial resistance value R0 and the real-time resistance values ​​R1 to R10;

[0079] Step S23, calculating the difference between each real-time resistance value and the initial resistance value; for example: R1-R0 (denoted as D1), R2-R0 (denoted as D2) ... R10-R0 (denoted as D10), and then obtaining 10 difference values;

[0080] Step S24: compare the 10 difference values ​​with the 10 preset difference values ​​one by one; assuming that the 10 preset difference values ​​are d1, d2, ..., d10, then compare the size of D1 with d1, the size of D2 with d2, ..., the size of D10 with d10;

[0081] Step S25: determine whether the difference value exceeds the preset difference value for more than 4 times in a row;

[0082] Step S26: If the difference exceeds the preset difference more than four times in a row, stop supplying power to the heating element 14 (step S32); otherwise, obtain the real-time resistance of the heating element 14 again 800 ms after the aerosol generating device is activated;

[0083] Step S27: Calculate the resistance change rate of the heating element 14 based on the real-time resistance of the heating element 14 obtained again;

[0084] Step S28, determining whether the resistance change rate exceeds the preset resistance change rate for more than four consecutive times; if the resistance change rate exceeds the preset resistance change rate for more than four consecutive times, stopping the power output to the heating element 14 (step S32); otherwise, continuing the comparison and determination;

[0085] Step S29: determining whether the real-time resistance value of the heating element 14 exceeds the over-temperature threshold value based on the real-time resistance value of the heating element 14 obtained again;

[0086] Step S30: If the real-time resistance of the heating element 14 exceeds the over-temperature threshold, the power output of the heating element 14 is reduced; otherwise, the comparison and judgment are continued;

[0087] Step S31 , determining whether the preset temperature is successfully maintained; if the preset temperature is not successfully maintained, reducing the power output of the heating element 14 ; otherwise, continuing the comparison and determination.

[0088] It should be noted that, in the above control process, after the aerosol generating device is started, it is feasible to only implement steps S26 to S32 , and it is also feasible to implement steps S22 to S25 after the aerosol generating device is started again.

[0089] like Figure 5 As shown, curve K1 represents the curve when the heating element 14 experiences dry burning between activation of the aerosol generating device and puffing (e.g., as shown by A in the figure), while curve K2 represents the curve when the heating element 14 does not experience dry burning between activation of the aerosol generating device and puffing. The ordinate in the figure represents the resistance of the heating element 14 (milliohms), and the abscissa represents the number of resistance measurements. It should be noted that for ease of illustration, the curves between curves K1 and K2 are not shown; reference should be made to curves K1 and K2 for further understanding.

[0090] In the first 800ms, by obtaining the initial resistance value and 10 real-time resistance values ​​of the heating element 14, calculating the difference between each real-time resistance value and the initial resistance value, and comparing the 10 differences with 10 preset differences one by one, it is determined whether the difference exceeds the preset difference for more than 4 times in a row, and whether dry burning of the heating element 14 occurs can be identified.

[0091] It should be noted that within the first 800ms, due to the extremely short duration and large temperature fluctuations, the slope method or the resistance change rate method cannot accurately determine whether the amount of liquid stored has decreased to the threshold, which can easily lead to false positives and affect the user's puffing experience. This example reduces or avoids false positives by performing a one-to-one comparison of multiple differences.

[0092] like Figure 6 As shown, curve K3 is a curve when the heating element 14 dry-burns when the aerosol generating device is puffed, and curve K4 is a curve when the heating element 14 does not dry-burn when the aerosol generating device is puffed (dry-burning occurs from the time the aerosol generating device is started to the time it is puffed).

[0093] After 800ms, the real-time resistance of the heating element 14 is again acquired, the resistance change rate of the heating element 14 is calculated, and the determination of whether the resistance change rate exceeds the preset resistance change rate more than four times in a row is made. This allows the determination of whether the heating element 14 has dry-burned. As shown by point B in the figure, the slope of curve K3 increases significantly after this point, confirming that the heating element 14 has dry-burned while the aerosol generating device is being puffed.

[0094] It should be noted that the above Figure 6 The described judgment method is not suitable for the entire suction stage, e.g. Figure 5 The situation shown. Since the resistance data fluctuates greatly from the time when the heating element 14 starts heating to a certain time point (for example, the T1 time point in the figure), the above judgment method can easily lead to misjudgment, thereby affecting the user's smoking experience. The time point can be determined according to the moment when the resistance change rate of the heating element 14 is reduced to 1% to 30% of the resistance change rate of the heating element 14 when the heating is started. Taking the T1 time point as an example, it can be determined through calculation that the moment when the resistance change rate of the curve K3 is reduced to 1% of the resistance change rate of the heating element 14 when the heating is started is the T1 moment. According to the horizontal axis, the sampling start time and the sampling interval time, it can be inferred that T1 = 800ms. Therefore, using the above judgment method after 800ms can reduce or avoid the occurrence of misjudgment.

[0095] like Figure 7 As shown, curve K5 is a curve when the heating element 14 dry-burns when the aerosol generating device is puffed, and curve K6 is a curve when the heating element 14 does not dry-burn when the aerosol generating device is puffed.

[0096] After 800ms, the real-time resistance value of the heating element 14 is again obtained and compared with the over-temperature threshold. If the real-time resistance value of the heating element 14 exceeds the over-temperature threshold, the power output to the heating element 14 is reduced. If the temperature of the heating element 14 is successfully maintained at the preset temperature, it can be determined that the heating element 14 has not dry-burned during puffing of the aerosol generating device. As shown in D in the figure, at this point, the real-time resistance value of the heating element 14 exceeds the over-temperature threshold, and after the power output to the heating element 14 is reduced, the temperature of the heating element 14 is successfully maintained at the preset temperature.

[0097] As shown at point C in the diagram, the real-time resistance of the heating element 14 exceeds the over-temperature threshold at this point. Even after reducing the power output to the heating element 14, the temperature of the heating element 14 is still not maintained at the preset temperature, and the resistance of the heating element 14 continues to rise. Therefore, it can be determined that the heating element 14 is dry-burning during puffing of the aerosol generating device.

[0098] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of this application. However, the present application can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of this application. The purpose of providing these embodiments is to make the understanding of the disclosure of this application more thorough and comprehensive. In addition, the above-mentioned technical features can be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of this application; further, it is obvious to those skilled in the art that improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. An aerosol generating device, characterized in that include: a liquid storage unit, used for storing a liquid capable of generating an aerosol; a heating element for heating the liquid; a liquid transfer unit for transferring the liquid stored in the liquid storage unit to the heating element; a power source for providing power to the heating element; a circuit configured to determine, after a preset time point after the heating element starts heating, whether the liquid stored in the liquid storage unit has decreased to a threshold value based on a difference between a resistance change rate of the heating element and a preset resistance change rate; The preset time point is determined according to the moment when the resistance change rate of the heating element decreases to 1% to 30% of the resistance change rate of the heating element when the heating is started; The circuit is configured to: Before a preset time point, obtaining an initial resistance value and M real-time resistance values ​​of the heating element; Calculating the difference between each real-time resistance value and the initial resistance value; Compare the M difference values ​​with the M preset difference values ​​one by one; If the difference value exceeds the preset difference value continuously for more than the preset number of times, it is determined that the liquid stored in the liquid storage unit has been reduced to a threshold value.

2. The aerosol generating device according to claim 1, wherein The preset time point is after 600ms.

3. The aerosol generating device according to claim 2, wherein: The preset time point is after 800ms.

4. The aerosol generating device according to claim 3, wherein: The preset time point is after 1000ms.

5. The aerosol generating device according to claim 1, wherein The circuit is configured to determine whether the liquid stored in the liquid storage unit has decreased to a threshold value based on the number of times the resistance change rate of the heating element continuously exceeds the preset resistance change rate.

6. The aerosol generating device according to any one of claims 1 to 5, characterized in that: The circuit is configured to store the real-time resistance value of the heating element after a preset time point in a preset buffer, and calculate the resistance change rate of the heating element: K j =(R N+j -R 0+j ) / R 0+j , where K j is the resistance change rate of the heating element, N is the length of the preset buffer zone, and j is a natural number.

7. The aerosol generating device according to claim 1 or 2, characterized in that: The circuit is configured to determine whether the liquid stored in the liquid storage unit has decreased to a threshold value based on the real-time resistance value of the heating element and the size of the over-temperature threshold value after a preset time point.

8. The aerosol generating device according to claim 7, wherein: The circuit is configured to: If the real-time resistance of the heating element exceeds the over-temperature threshold, the power output to the heating element is reduced in order to maintain the temperature of the heating element at a preset temperature, or to maintain the real-time resistance of the heating element at a resistance corresponding to the preset temperature; If the power output to the heating element is reduced to the preset power, but the temperature of the heating element is still not successfully maintained at the preset temperature, or the real-time resistance of the heating element is still not successfully maintained at the resistance value corresponding to the preset temperature, it is determined that the liquid stored in the liquid storage unit has been reduced to a threshold value.

9. The aerosol generating device according to claim 1, wherein the circuit comprises a processor and a sampling resistor; The processor has a first voltage sampling port, a second voltage sampling port and a push-pull output port; The heating element and the sampling resistor are connected in series between the positive electrode of the power supply and the push-pull output port; and both ends of the sampling resistor are connected to the first voltage sampling port and the second voltage sampling port respectively.

10. The aerosol generating device according to claim 1, wherein the circuit comprises a processor, a switch tube, a heating element, and a sampling resistor connected in series between the positive and negative electrodes of a power supply; The processor has a first voltage sampling port, a second voltage sampling port and a control port; The control port is connected to the control end of the switch tube to control the on or off of the switch tube; The first voltage sampling port is provided between the switching tube and the heating element, and the second voltage sampling port is provided between the heating element and the sampling resistor.

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