Pressure control method of pressure cooking utensil

Abstract

The invention provides a pressure control method of a pressure cooking utensil, and relates to the pressure cooking utensil, the pressure control method of the pressure cooking utensil comprises the following steps: S1, maintaining a first heating state, obtaining a real-time temperature T in a cooking cavity of the pressure cooking utensil, and if the real-time temperature T reaches a switching temperature T0, switching a heating device from the first heating state to a second heating state; s2, the second heating state is maintained, and whether the real-time temperature T reaches the pressure maintaining temperature T1 within the preset time t0 or not is judged; if yes, entering a pressure maintaining working stage; if not, the switching temperature T0 is increased, the increased switching temperature T0 is not larger than the pressure maintaining temperature T1, and the step S1 is executed again. The pressure control method of the pressure cooking utensil is used for solving the technical problems that the influence of waste heat is reduced due to the fact that heating is stopped only once at a fixed temperature threshold value in the prior art, but a cooking program cannot be flexibly adjusted, different cooking conditions cannot be adapted, and temperature overshoot is difficult to further reduce.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure cooking appliances, in particular to a pressure control method of a pressure cooking appliance. BACKGROUND

[0002] For a pressure cooking appliance such as a micro-pressure rice cooker or an electric pressure cooker, it is often necessary to detect the pressure in the cooking cavity and control the pressure in the cooking cavity according to a recipe.

[0003] In order to know the pressure in the cooking cavity, the prior art provides a pressure detection device for directly detecting the pressure in the cooking cavity, such as the pressure heating cooker disclosed in the prior art CN202311377248.5, wherein the pressure detection part is arranged on the metal cover provided on the upper cover, and the pressure detection part is communicated with the cooking cavity to detect the pressure change in the cooking cavity.

[0004] In addition to directly detecting the pressure in the cooking cavity, the pressure in the cooking cavity can also be known by measuring the displacement of the inner pot during cooking. For example, the electric pressure cooker disclosed in the prior art CN200710153849.2 is provided with a capacitive sensor between the inner pot and the lower shell. When the displacement of the inner pot caused by the pressure change drives the moving plate of the capacitive sensor to change the distance or effective corresponding area between the plates, the capacitive signal changes, and thus the pressure value in the cooking cavity is known.

[0005] Further, the temperature in the cooking cavity or the inner pot can also be measured to know the pressure in the cooking cavity.

[0006] For example, the cooking equipment disclosed in the prior art CN202110549903.5 detects the temperature of the pot body by a temperature measuring device, calculates the pressure in the pot body according to the corresponding relationship between the temperature and the pressure, and then controls the working of the heating device to achieve the purpose of controlling the pressure of the cooking equipment by the temperature measuring device.

[0007] In use, it is found that the heating device stops heating when the pressure or temperature in the cooking cavity meets the preset condition. However, after the heating stops, there is still "residual heat" in the heating device and the inner pot, which will continue to heat the inner pot, resulting in that the temperature and pressure exceed the preset pressure holding value.

[0008] In order to reduce the influence of the residual heat of the heating device and the inner container on the cooking process, the prior art CN202110549903.5 controls the heating device to work in a cycle mode of stopping heating for a second preset time after heating for a first preset time, until the temperature of the pot body is greater than or equal to a first temperature threshold. In this heating process, the intermittent heating mode allows the heating device to cool down during the stopping heating stage, thereby reducing the interference with the temperature measuring device. However, during the stopping heating process, even if the temperature measurement is more accurate, the inner container and the cooking cavity will still be affected by the residual heat, causing the temperature to continue to rise and exceed the original pressure holding value set by the program, thereby affecting the cooking effect.

[0009] Further, the prior art CN03152673.X controls the bottom heating device and the cover heating device to heat simultaneously during the heating step, until the pot sensor detects a first set temperature, the bottom heating device stops heating, and the cover heating device continues to assist heating, and the temperature is raised to a second set temperature by using the residual heat. By stopping the bottom heating device in advance and raising the temperature by using the residual heat, the problem of cake burning caused by excessive heating of the pot bottom is avoided.

[0010] The temperature point at which the bottom heating device stops heating (the first set temperature) and the temperature point at which the residual heat stops rising (i.e., the second set temperature) are both preset temperature points of the program. It does not take into account that in different use environments, the pot body temperature is difficult to reach the second set temperature (that is, with the assistance of the top heating device), resulting in poor cooking effect; nor does it take into account that in different use environments, the pot body temperature reaches the second set temperature faster than expected, and the pot body temperature is difficult to reach the second set temperature, resulting in poor cooking effect. SUMMARY

[0011] The present application aims to provide a pressure control method for a pressure cooking appliance, which solves the technical problem of the prior art that relies on stopping heating only once at a fixed temperature threshold, thereby reducing the influence of residual heat, but cannot flexibly adjust the cooking program, cannot adapt to different cooking conditions, and is difficult to further reduce temperature overshoot.

[0012] The embodiment of the present application provides a pressure control method for a pressure cooking appliance, comprising the following steps: S1: maintaining a first heating state, acquiring a real-time temperature T in a cooking cavity of the pressure cooking appliance, and switching a heating device from the first heating state to a second heating state if the real-time temperature T reaches a switching temperature T0, wherein the heating power of the first heating state is greater than the heating power of the second heating state;

[0013] S2: maintaining the second heating state, judging whether the real-time temperature T reaches a pressure holding temperature T1 within a preset time t0; if yes, entering a pressure holding working stage; if no, increasing the switching temperature T0, and the increased switching temperature T0 is not greater than the pressure holding temperature T1, and returning to step S1.

[0014] In some embodiments of the present application, a plurality of temperature thresholds are preset in sequence, and the increased switching temperature T0 is selected as a temperature threshold greater than the real-time temperature T.

[0015] In some embodiments of the present application, the positive difference between adjacent temperature thresholds is the same.

[0016] In some embodiments of the present application, the increased switching temperature T0 is increased to half of the sum of the real-time temperature T and the holding temperature T1.

[0017] In some embodiments of the present application, the initial switching temperature T0 is half of the sum of the pre-pressing temperature and the holding temperature T1.

[0018] In some embodiments of the present application, the heating power of the second heating state is 0W.

[0019] In some embodiments of the present application, before returning to step S1, the heating power of the first heating state is reduced by the adjustment power ΔP.

[0020] In some embodiments of the present application, the adjustment power ΔP is a fixed value.

[0021] In some embodiments of the present application, before returning to step S1, the heating power of the first heating state is reduced by the adjustment power ΔP, and the preset time t0 is reduced by a preset value Δt each time.

[0022] The embodiments of the present application provide a pressure control method of a pressure cooking appliance, and the method comprises the following steps: S1: acquiring a real-time pressure P in a cooking cavity of the pressure cooking appliance; if the real-time pressure P reaches a switching pressure P0, a heating device is switched from a first heating state to a second heating state, wherein the heating power of the first heating state is greater than the heating power of the second heating state.

[0023] S2: maintaining the second heating state, and determining whether the real-time pressure P reaches a holding pressure P1 within a preset time t0; if yes, entering a holding working phase; if no, increasing the switching pressure P0, and the increased switching pressure P0 is not greater than the holding pressure P1, and returning to step S1.

[0024] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0025] The temperature in the cooking cavity is switched to a lower heating state each time the switching temperature T0 is reached, and a waiting time t0 is maintained to observe whether the residual heat can raise the temperature in the cooking cavity to the pressure maintaining temperature T1. If the current switching temperature T0 is low (i.e. the pressure maintaining temperature T1 cannot be reached at all in the case of low heating power or relying on residual heat), the switching temperature T0 is increased before returning to step S1, and the cycle is repeated multiple times until the pressure maintaining temperature T1 is successfully reached. Compared with the conventional scheme of "stopping heating at a fixed temperature point and only once using residual heat to raise the temperature to the pressure maintaining temperature", the dynamically adjustable switching temperature T0 in the present application can also gradually approach T1 through multiple heating, thereby preventing overshooting and avoiding the problem of slow heating of the cooking cavity, and flexibly coping with different situations of pot load and residual heat difference, thereby ensuring the use experience and cooking effect. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic diagram of a pressure cooking appliance according to an embodiment of the present application.

[0027] Figure 2 is a flowchart of the cycle of steps S1 and S2 according to an embodiment of the present application.

[0028] Figure 3 is a flowchart of the selection of a temperature threshold higher than the real-time temperature T for the switching temperature T0 according to an embodiment of the present application.

[0029] Figure 4 is a flowchart of the setting of the switching temperature T0 as the intermediate value of the real-time temperature T and the pressure maintaining temperature T1 according to an embodiment of the present application.

[0030] Figure 5 is a flowchart of the gradual reduction of the heating power of the first heating state during the cycle according to an embodiment of the present application.

[0031] Figure 6 is a flowchart of the gradual reduction of the preset time t0 with the gradual reduction of the heating power of the first heating state according to an embodiment of the present application.

[0032] FIG.:

[0033] 1 - pot body, 101 - heating device, 2 - inner pot, 200 - cooking cavity, 3 - pot cover, 4 - temperature measuring device. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0035] For pressure cooker, micro-pressure rice cooker or other pressure cooking appliance, as shown in the figure, the cooking appliance generally includes a pot body 1, a pot cover 3 and an inner pot 2. The pot body 1 and the pot cover 3 are usually external structures for wrapping the whole cooking appliance, and the pot cover 3 can be rotatably connected with the pot body 1 or can be separately arranged from the pot body 1. The inner pot 2 is placed in the pot body 1, and when the pot cover 3 is closed, the inner pot 2 and the pot cover 3 form a cooking cavity 200, and the pressure cooking appliance heats the cooking cavity 200 through a heating device 101. The common heating device 101 is usually a bottom heating or IH heating. Figure 1

[0036] For bottom heating, the heating device 101 generally includes a heating disc arranged in the inner pot 2, and when the inner pot 2 is placed in the pot body 1, the heating disc is in contact with the bottom of the inner pot 2. During cooking, the heating disc generates heat and transmits the heat to the inner pot 2 by heat conduction, and then the inner pot 2 transmits the heat to the food.

[0037] For IH heating, the heating device 101 generally includes an electromagnetic coil arranged in the inner pot 2, and the arrangement of the electromagnetic coil is relatively flexible. When the inner pot 2 is placed in the pot body 1, the electromagnetic coil can not only be located below the inner pot 2, but also can be arranged around the inner pot 2. During cooking, the electromagnetic coil generates an alternating magnetic field to make the metal inner pot 2 generate eddy current, thereby achieving self-heating.

[0038] Generally, the pressure cooking appliance can directly detect the temperature in the cooking cavity 200 through a temperature measuring device 4, thereby measuring the pressure value in the cooking cavity 200. In the pressure cooking appliance, when the temperature in the cooking cavity 200 is greater than 100℃, the pressure in the cooking cavity 200 starts to increase, and for every 1℃ increase in the starting temperature, the relative pressure in the cooking cavity 200 increases by 5KPa. For example, when the temperature in the cooking cavity 200 is 106℃ (the relative pressure in the cooking cavity 200 is approximately 30kPa), 108℃ (approximately 40kPa), 110℃ (approximately 50kPa) and 112℃ (approximately 60kPa). In order to achieve pressure cooking, the pressure maintaining temperature T1 is usually higher than 100℃. When the temperature in the cooking cavity 200 reaches the set value, there is still "residual heat" in the heating device 101 and the inner pot 2, and these residual heat will continue to heat the inner pot 2 in a short time, causing the temperature and pressure in the cooking cavity 200 to exceed the originally set temperature value or pressure value (hereinafter referred to as temperature overshoot or temperature overshoot), resulting in abnormal exhaust and affecting the normal cooking of food.

[0039] In order to reduce the influence of "residual heat" on the cooking process of food, the prior art provides a residual heat heating step before the temperature in the cooking cavity 200 reaches the target temperature: in this step, the bottom heating device 101 is paused, only the top heating is retained or the residual heat is used to make the temperature rise to the target temperature.

[0040] ​However, this existing technology relies too heavily on a fixed single-point temperature threshold, resulting in limited control precision and difficulty in adjusting to environmental changes. Furthermore, the interval between the temperature threshold for stopping heating and the temperature threshold for resuming heating in this technology is relatively large (even as high as 10°C), and relying solely on a single residual heat heating step can easily affect the normal cooking of food. Specifically, if the residual heat is insufficient, the lid heating device 101 may not be able to ensure that the temperature inside the cooking cavity 200 rises to the resumption heating temperature, delaying the transition to the next stage and compromising cooking effectiveness; conversely, if the residual heat is too strong, the lid heating device 101 may cause the temperature inside the cooking cavity 200 to overshoot.

[0041] Therefore, to address the technical problem that existing technologies rely on a single, fixed temperature threshold to stop heating once, thereby reducing the impact of residual heat, but lack flexibility in adjusting the cooking program, cannot adapt to different cooking conditions, and struggle to further reduce temperature overshoot, this invention includes the following steps:

[0042] Step S1: Maintain the first heating state and obtain the real-time temperature T inside the cooking chamber 200 of the pressure cooker, i.e., monitor the real-time temperature inside the cooking chamber 200 in real time. If the real-time temperature T reaches the switching temperature T0, switch the heating device 101 from the first heating state to the second heating state. The heating power of the first heating state is greater than that of the second heating state to prevent the temperature from continuing to rise sharply. Step S2: Maintain the second heating state and determine whether the real-time temperature T reaches the pressure holding temperature T1 within a preset time t0. Observe whether the real-time temperature can slowly continue to rise to the pressure holding temperature T1 by relying on residual heat or low power during this period (e.g., 100-50s). If so, enter the pressure holding stage, indicating that the residual heat or the current low power heating is sufficient to push the temperature to the target value, and enter the pressure holding stage without further heating.

[0043] If not, it indicates insufficient residual heat or a large load, requiring continued heating; increase the switching temperature T0, and ensure that the increased switching temperature T0 is not greater than the pressure holding temperature T1, return to step S1, and repeat: first heat to high power (first heating state) to the new switching temperature T0, then observe whether the temperature inside the cooking cavity 200 can rise to the pressure holding temperature T1 under low power / residual heat conditions (second heating state), repeat multiple times until the pressure holding temperature T1 is successfully reached.

[0044] In this invention, when there is insufficient residual heat (the second heating state cannot raise the temperature to T1), the goal is no longer to raise the temperature to the holding temperature T1 through a single second heating state. Instead, T0 is increased and step S1 is repeated to dynamically adjust the switching temperature T0 and avoid overshoot. At the same time, steps S1 and S2 can be cycled multiple times to control the heating rate and achieve a stable rise to the holding temperature T1 with the help of residual heat.

[0045] The preset time t0 is the duration of the single second heating state. Because the temperature rise in the second heating state is not instantaneous, the preset time t0 is needed to verify whether the holding temperature T1 can be reached.

[0046] In general, the temperature in the cooking cavity 200 is switched to a lower heating state each time the switching temperature T0 is reached, and a waiting time t0 is maintained to observe whether the residual heat can raise the temperature in the cooking cavity 200 to the holding temperature T1. If the current switching temperature T0 is low (i.e., the holding temperature T1 cannot be reached at all in the low heating power or by relying on residual heat), the switching temperature T0 is increased before returning to step S1, and the cycle is repeated multiple times until the holding temperature T1 is successfully reached. Compared with the conventional scheme of stopping heating at a fixed temperature point and using residual heat to raise the temperature to the holding temperature only once, the dynamically adjustable T0 in the present application can gradually approach T1 through multiple heating, thereby preventing overshooting and avoiding the problem of slow temperature rise in the cooking cavity 200, and flexibly coping with different situations of the load in the pot and the residual heat, thereby ensuring the use experience and cooking effect.

[0047] In some embodiments, the second heating state described above can include two states of low-power heating or stopping heating. The stopping heating or low-power heating can be selected according to the heating power in the first heating state or the size of the residual heat. It can be understood that when the heating power in the first heating state is small or the residual heat is small, the residual heat cannot continuously increase the temperature in the cooking cavity 200, and the second heating state described above can adopt low-power heating, which has a heating power smaller than that of the first heating state, to continue to provide a small amount of energy to the cooking cavity 200, so that the cooking cavity 200 can still maintain a high temperature. When the heating power in the first heating state is large or the residual heat is large, the residual heat itself is sufficient to continuously increase the temperature in the cooking cavity 200, and the second heating state can adopt stopping heating, thereby preventing the temperature in the cooking cavity 200 from rising too high.

[0048] In some embodiments, the heating power in the first heating state and the heating power in the second heating state can refer to the total heating power of the pressure cooking appliance.

[0049] In actual use, the NTC can be directly inserted into the cooking cavity 200 to measure the temperature in the cooking cavity 200.

[0050] Embodiment one:

[0051] For an electric pressure cooker, the entire cooking process generally includes a pressure rising stage, a pressure holding stage, and a pressure reducing stage. The pressure control method involved in the present application can be applied to the pressure rising stage.

[0052] In some embodiments of the present embodiment, the maximum heating power of the electric pressure cooker can be 700W, the capacity of the cooking cavity 200 can be 3L, the holding temperature T1 can be 112℃ (approximately equal to 60KPa (relative pressure)), the initial switching temperature T0 can be 106℃ (approximately equal to 30KPa (relative pressure)), the preset time t0 can be set to 30s, the heating power in the first heating state is 700W, and the heating power in the second heating state is 50W.

[0053] In the above embodiments, as shown in Figure 2 the pressure control method is as follows:

[0054] 1. Step S1: The heating device 101 heats the inner pot 2 at 700W (first heating state), and the real-time temperature T in the cooking cavity 200 of the pressure cooking appliance is obtained. If the real-time temperature T reaches 106℃, the heating device 101 is switched from 700W (first heating state) to 50W (second heating state). Step S2 is entered: The heating power of the heating device 101 is 50W (second heating state) and is maintained for 30s (preset time t0), and it is judged whether the real-time temperature T reaches 112℃ (holding temperature T1); if yes, the pressure holding working phase is entered. If no, the switching temperature T0 is increased from 106℃ to 108℃, and step S1 is returned.

[0055] 2. Step S1: The heating device 101 heats the inner pot 2 at 700W (first heating state), and if the real-time temperature T reaches 108℃, the heating device 101 is switched from 700W (first heating state) to 50W (second heating state). Step S2 is entered: The heating power of the heating device 101 is 50W (second heating state) and is maintained for 30s (preset time t0), and it is judged whether the real-time temperature T reaches 112℃ (holding temperature T1); if yes, the pressure holding working phase is entered. If no, the switching temperature T0 is increased from 108℃ to 110℃, and step S1 is returned.

[0056] 3. Step S1: The heating device 101 heats the inner pot 2 at 700W (first heating state), and if the real-time temperature T reaches 110℃, the heating device 101 is switched from 700W (first heating state) to 50W (second heating state). Step S2 is entered: The heating power of the heating device 101 is 50W (second heating state) and is maintained for 30s (preset time t0), and it is judged whether the real-time temperature T reaches 112℃ (holding temperature T1); if yes, the pressure holding working phase is entered. If no, the switching temperature T0 is increased from 110℃ to 112℃, and step S1 is returned.

[0057] 4. Step S1: the heating device 101 heats the inner pot 2 at 700W (first heating state), and if the real-time temperature T reaches 112°C, the heating device 101 is switched from 700W (first heating state) to 50W (second heating state). Step S2: the heating power of the heating device 101 is 50W (second heating state) and is maintained for 30s (preset time t0), and it is judged whether the real-time temperature T reaches 112°C (pressure maintaining temperature T1); if yes, it enters the pressure maintaining working phase.

[0058] In the embodiment, when the residual heat is insufficient, the temperature in the cooking cavity 200 is gradually increased by multiple switching of steps S1 and S2, so as to realize more accurate temperature control; when the residual heat is sufficient, or when the temperature condition is met in the step S1, S2 cycle process, it can directly enter the pressure maintaining working phase. Therefore, the embodiment can flexibly adjust the cooking program according to the working condition, avoid the temperature overshoot in the cooking cavity 200, and take into account the cooking effect.

[0059] The preset time t0 is not fixed, and can be appropriately adjusted according to the heating power of the first and second heating states and the like. If the preset time t0 is too short, the residual heat is not fully released, and if the first heating state is entered too quickly, the temperature overshoot may still occur; if the preset time t0 is too long, the overall cooking efficiency will be slowed down. Therefore, the preset time t0 can be set according to the capacity of the cooking cavity 200 and the heating power of the first and second heating states.

[0060] For example, when the heating power of the first heating state is 1200W, the residual heat of the heating device 101 and the inner pot 2 is large, and the preset time t0 can be extended. The preset time t0 can be increased from 30s (when the first heating state power is 700W) to 40s.

[0061] For example, when the heating power of the second heating state is 0W, the temperature change in the cooking cavity 200 is small within the preset time t0, and the preset time t0 can be shortened. The preset time t0 can be shortened from 30s (when the second heating state power is 50W) to 25s.

[0062] For example, when the heating power of the first heating state is 300W, and the heating power of the second heating state is 0W, the preset time t0 can be further shortened. The preset time t0 can be shortened to 15s.

[0063] Example two:

[0064] The embodiment is provided with a plurality of temperature thresholds that increase sequentially, and the switching temperature T0 is selected to be greater than the real-time temperature T. That is, the switching temperature T0 in the embodiment can be selected from a set of "temperature thresholds that increase sequentially", and the most suitable "next target" is dynamically selected to switch heating as the actual temperature in the cooking cavity 200 changes; if the residual heat is insufficient, multiple cycles are performed, and the switching temperature T0 is sequentially selected to be a temperature threshold that increases; if the residual heat is sufficient but the temperature in the cooking cavity 200 does not reach the holding temperature T1, the switching temperature T0 can be directly selected to be a larger temperature threshold, so as to maximize the residual heat and shorten the heating cycle.

[0065] Therefore, in some embodiments of the present embodiment, the switching temperature T0 is selected from a plurality of temperature thresholds that increase sequentially. Specifically, the "temperature threshold" can be regarded as a series of temperature thresholds that are set in advance, each of which is slightly higher than the previous one but less than the holding temperature T1. For example: 106°C, 108°C, 110°C, 112°C (= holding temperature T1). In step S2, the second heating state is maintained, and it is determined whether the real-time temperature T reaches the holding temperature T1 within the preset time t0. If not, the pressure cooker adjusts the switching temperature T0 to be the next temperature threshold that is greater than the real-time temperature T, the increased switching temperature T0 is less than or equal to the holding temperature T1 and greater than the real-time temperature T, and returns to step S1.

[0066] As shown in Figure 3 , it is assumed that the initial switching temperature T0 is selected to be the first temperature threshold 106°C. When the real-time temperature T rises to 106°C in step S1, it enters step S2, switches to the second heating state, and after 30s (preset time t0), the real-time temperature T is 109°C, which does not reach the holding temperature 112°C (T1). It indicates that the original switching temperature T0 (= 106°C) is too low, and the switching temperature T0 needs to be selected to be a higher temperature threshold based on the real-time temperature T. In order to reduce the number of cycles, the switching temperature T0 needs to be selected to be a temperature threshold that is greater than the real-time temperature T. At this time, the switching temperature T0 can be selected to be 110°C, and it enters step S1. When the real-time temperature T rises to 110°C in step S1, it enters step S2, switches to the second heating state, and after 30s (preset time t0), it reaches the holding temperature 112°C (T1).

[0067] In the execution process of the embodiment, if one or more temperature thresholds are exceeded within the preset time t0 (for example, the real-time temperature T rises from 106°C to 110°C in one second heating state), the intermediate temperature thresholds are skipped, and the switching temperature T0 is directly selected to be a higher temperature threshold (for example, the switching temperature T0 is 110°C). In general, the embodiment not only reduces the probability of temperature shock, but also realizes flexible adjustment of the cooking program and shortens the heating time.

[0068] In some embodiments, there can be multiple temperature thresholds greater than the real-time temperature T, and the switching temperature T0 is generally selected as the temperature threshold closest to the real-time temperature T, so as to reduce the duration of the first heating state.

[0069] In this embodiment, the size of the positive difference between the temperature thresholds means the temperature rising interval during the duration of the first heating state. The smaller the positive difference between the temperature thresholds, the less the temperature rises in the first heating state, and the shorter the duration of the first heating state, which is beneficial to more controlled temperature rising of the cooking cavity 200. The larger the positive difference between the temperature thresholds, the longer the duration of the first heating state, and the temperature in the cooking cavity 200 can be closer to the pressure maintaining temperature T1 faster.

[0070] In some embodiments, the positive difference between adjacent temperature thresholds described above can be the same, which means that the increment of adjacent temperature thresholds is the same, and the maximum temperature rising amplitude of the first heating state is consistent in multiple cycles of steps S1 and S2, so as to achieve more smooth temperature control. For example, the temperature thresholds include 103°C, 106°C, 109°C and 112°C, and the maximum temperature rising amplitude of the first heating state is 3°C.

[0071] In some embodiments, the positive difference between adjacent temperature thresholds described above can be different, which means that the increment of adjacent temperature thresholds is not the same, and more precise control of temperature change can be achieved according to actual needs.

[0072] For example, when the temperature in the cooking cavity 200 just reaches 100°C (generally considered that the pressure in the cooking cavity 200 starts to increase at this time), and is far away from 112°C (the pressure maintaining temperature T1), the positive difference between the temperature thresholds can be relatively large. When the temperature in the cooking cavity 200 reaches 106°C, it is closer to the pressure maintaining temperature T1 (112°C), and in order to more accurately adjust the temperature in the cooking cavity 200, the positive difference between the temperature thresholds can be relatively small. Finally, the temperature thresholds include 100°C, 106°C, 108°C and 110°C, and in this process, the maximum temperature rising amplitude of the first heating state decreases from 6°C to 2°C.

[0073] Example Three:

[0074] In the embodiment, the switching temperature T0 is set to be half of the sum of the holding temperature T1 and the real-time temperature T. When the switching temperature T0 is set to be half of the sum of the holding temperature T1 and the real-time temperature T, the temperature increasing range of the first heating state is reduced when the process enters step S1 again, so that the residual heat when the process enters step S2 is reduced. If the residual heat is not enough during this period, the real-time temperature T still does not reach the holding temperature T1, but the real-time temperature T is further close to the holding temperature T1. Therefore, the temperature increasing range of the first heating state is further reduced when the process enters step S1 again, so that the temperature increasing range of the first heating state is adjusted more accurately. The pressure control method of the embodiment can dynamically adjust the switching temperature T0 without a large number of values, gradually reduce the temperature increasing range of the first heating state, and adapt to different cooking conditions while avoiding temperature overshoot.

[0075] As shown in FIG. 1, it is assumed that the initial switching temperature T0 is 104°C. Figure 4 1. Step S1, maintain the first heating state. When the real-time temperature T rises to the switching temperature T0 (104°C), enter step S2. Switch to the second heating state and continue for 15s (preset time t0). The real-time temperature T is 108°C, which does not reach the holding temperature 114°C (T1). At this time, the switching temperature T0 is half of the sum of the holding temperature T1 (114°C) and the current real-time temperature T (108°C), i.e., the switching temperature T0=(114°C+108°C) / 2=111°C.

[0076] 2. Step S1, maintain the first heating state. When the real-time temperature T rises to the switching temperature T0 (111°C), enter step S2. Switch to the second heating state and continue for 15s (preset time t0). The real-time temperature T is 112°C, which does not reach the holding temperature 114°C (T1). At this time, the switching temperature T0 is half of the sum of the holding temperature T1 (114°C) and the current real-time temperature T (112°C), i.e., the switching temperature T=(114°C+112°C) / 2=113°C.

[0077] 3. Step S1, maintain the first heating state. When the real-time temperature T rises to the switching temperature T0 (113°C), enter step S2. Switch to the second heating state and continue for 15s (preset time t0). The real-time temperature T is 114°C, which reaches the holding temperature 114°C (T1), and enters the holding working stage.

[0078] In the embodiment, the closer to the holding temperature T1, the smaller the temperature increasing range of the first heating state, so that the temperature rising process in the cooking cavity 200 is dynamically adjusted, and enough temperature increasing space is left for the second heating state to slowly approach the holding temperature T1, so as to avoid cooking problems caused by overshoot or excessive pressure.

[0079] Example Four:

[0080] In actual use, the initial switching temperature T0 is half of the sum of the upper pressure temperature and the holding temperature T1. That is, the switching temperature T0 can change with the holding temperature T1, compared with the fixed switching temperature T0. It is beneficial to avoid the switching temperature T0 being too close to the target temperature T1, thereby leaving enough space for the second heating state to rise in temperature, further preventing temperature overshoot; it can also avoid the switching temperature T0 being too close to the upper pressure temperature, thereby ensuring the heating efficiency of the pressure cooking appliance.

[0081] Generally, the temperature in the cooking cavity 200 starts to rise when it is greater than 100°C, so the upper pressure temperature is generally 100°C, and the holding temperature T1 is greater than 100°C.

[0082] Embodiment Five:

[0083] In this embodiment, the heating power of the first heating state is reduced by the adjustment power △P before returning to step S1. After entering the second heating state and maintaining for a preset time t0, although the real-time temperature T in the cooking cavity 200 does not rise to the holding temperature T1, the temperature in the cooking cavity 200 is still closer to the holding temperature T1, and the heating space of the first heating state and the second heating state is getting smaller and smaller. Therefore, the heating power of the first heating state is reduced each time before returning to step S1, so as to reduce the residual heat when entering step S2 next time, so that the temperature in the cooking cavity 200 is more stable and closer to the holding temperature T1.

[0084] As shown in FIG. 2, it is assumed that the initial power of the first heating state is 500W, and the capacity of the cooking cavity 200 is 2L. Figure 5 1. Step S1, the first heating state heats the cooking cavity 200 at a heating power of 500W, and when the real-time temperature T in the cooking cavity 200 rises to the switching temperature T0 (104°C), step S2 is entered; the switching temperature T0 is switched to the second heating state, and after 20s (preset time t0) of continuous heating at a heating power of 0W, the real-time temperature T is 108°C, which does not reach the holding temperature T1 (112°C), at which time the switching temperature T0 can be raised to 110°C.

[0085] 2. Step S1 is entered, and the heating power of the first heating state is reduced from 500W to 400W, at which time the adjustment power △P is 100W, and when the real-time temperature T rises to the switching temperature T0 (110°C), step S2 is entered; the switching temperature T0 is switched to the second heating state and maintained for 20s (preset time t0), and after that, the real-time temperature T is 112°C, which reaches the holding temperature T1 (112°C), and enters the holding working phase.

[0086] The adjustment power △P is mainly used to reduce the heating power of the first heating state next time when the switching temperature T0 cannot make the temperature of the cooking cavity 200 rise to the holding temperature T1 within the preset time t0.

[0087] In some embodiments, the adjustment power △P can be adjusted according to the initial power of the first heating state and the capacity of the cooking cavity 200. When the initial power of the first heating state is low (e.g., 500 W), the adjustment power △P can be 50 W to 150 W, preventing the heating power of the first heating state from being too small and affecting the temperature rising efficiency. When the initial power of the first heating state is large (e.g., 1200 W), the adjustment power △P can be 100 W to 200 W, preventing the heating power of the first heating state from being too large and reducing the probability of temperature shock.

[0088] In some embodiments, the adjustment power △P can be adjusted according to the capacity of the cooking cavity 200. The capacity of the cooking cavity 200 affects the upper limit of the food and liquid that can be accommodated. The larger the capacity of the cooking cavity 200, the larger the specific heat capacity in the cooking cavity 200, and the slower the temperature change, at which time a larger adjustment power △P can be selected. The smaller the capacity of the cooking cavity 200, the smaller the specific heat capacity in the cooking cavity 200, and the faster the temperature change, at which time a smaller adjustment power △P can be selected. For example, when the capacity of the cooking cavity 200 is 3 L, the initial power of the first heating state is 700 W, and the adjustment power △P can be 150 W. For example, when the capacity of the cooking cavity 200 is 2 L, the initial power of the first heating state is 700 W, and the adjustment power △P can be 125 W.

[0089] In some embodiments, the above-mentioned adjustment power △P can be a fixed value, that is, the heating power of the first heating state changes by the same amount, which can achieve more uniform temperature control. For example: the heating power of the first heating state can start from 700 W and decrease by 120 W each time the pressure maintaining temperature T1 is not reached, at which time the adjustment power △P is fixed at 120 W.

[0090] In some embodiments, the above-mentioned adjustment power △P can be a variable value, and the heating power of the first heating state changes by different amounts, which can achieve more precise control of temperature changes according to actual needs.

[0091] For example: the heating power of the first heating state can start from 700 W and decrease by the adjustment power △P each time the pressure maintaining temperature T1 is not reached, where the adjustment power △P starts from 120 W and decreases by 10 W each time, and finally the heating power of the first heating state changes as follows: 700 W, 580 W (△P = 120 W), 470 W (△P = 110 W), 370 W (△P = 100 W), 280 W (△P = 90 W), etc.

[0092] Example Five:

[0093] In this embodiment, before returning to step S1, the heating power of the above-mentioned first heating state is reduced by the adjustment power △P, and the preset time t0 is reduced by the preset value △t each time.

[0094] The difference between the present embodiment and the above embodiments mainly lies in that the preset time t0 is adjusted to be smaller along with the heating power of the first heating state before the step S2 returns to the step S1, which avoids causing temperature overshoot while taking into account the efficiency of temperature rise and can adapt to different cooking conditions.

[0095] As shown in FIG. 1, it is assumed that the initial power of the first heating state is 700 W and the capacity of the cooking cavity 200 is 5 L. Figure 6 1. In step S1, the first heating state heats the cooking cavity 200 at a heating power of 700 W. When the real-time temperature T in the cooking cavity 200 rises to the switching temperature T0 (106 ℃), the step S2 is entered. After switching to the second heating state and continuing for 25 s (the preset time t0), the real-time temperature T is 109 ℃, which does not reach the pressure maintaining temperature T1 (112 ℃), at which time the switching temperature T0 can be raised to 110 ℃. The heating power of the first heating state is reduced from 700 W to 550 W, and the preset time t0 is reduced from 30 s to 25 s, with the preset value At being 5 s.

[0096] 2. In step S1, the heating power of the first heating state is 550 W. When the real-time temperature T rises to the switching temperature T0 (110 ℃), the step S2 is entered. After switching to the second heating state and continuing for 25 s (the preset time t0), the real-time temperature T reaches the pressure maintaining temperature T1 (112 ℃), and the pressure maintaining working phase is entered.

[0097] In general, because the heating power of the first heating state is continuously reduced in the cycle, the residual heat is reduced when the step S2 is entered, so the preset time t0 can be reduced to match the current heating state, thereby enhancing the adaptability to different environments.

[0098] In some embodiments, the setting of the preset time t0 is mainly affected by the capacity of the cooking cavity 200 and the heating power of the first heating state. A smaller capacity of the cooking cavity 200 (for example, 1 L to 3 L) is more obviously affected by the residual heat, so a long preset time t0 is not needed, and the preset time t0 can be set to 10 s to 30 s. A larger capacity of the cooking cavity 200 (for example, 3 L to 5 L) is more slowly affected by the residual heat, so sufficient preset time t0 can be left for temperature rise, and the preset time t0 can be set to 20 s to 50 s. The above heating power of the first heating state affects the size of the residual heat in the second heating state. The larger the heating power of the first heating state, the more obviously the cooking cavity 200 is affected by the residual heat. The smaller the heating power of the first heating state, the more slowly the cooking cavity 200 is affected by the residual heat.

[0099] In some embodiments, the preset value Δt can also be affected by the preset time t0, in order to avoid the adjusted t0 being too small, in use, the preset value Δt≤t0_initial value x 20%. For example, when the initial preset time t0 is 30s, the maximum preset value Δt is not greater than 6s.

[0100] Embodiment six:

[0101] Step S1: maintain the first heating state, obtain the real-time pressure P in the cooking cavity 200 of the pressure cooker, and if the real-time pressure P reaches the switching pressure P0, switch the heating device 101 from the first heating state to the second heating state, the heating power of the first heating state is greater than the heating power of the second heating state;

[0102] Step S2: maintain the second heating state, and determine whether the real-time pressure P reaches the pressure maintaining pressure P1 within the preset time t0; if yes, enter the pressure maintaining working phase; if no, increase the switching pressure P0, and the increased switching pressure P0 is not greater than the pressure maintaining pressure P1, and return to step S1.

[0103] The difference between the present embodiment and the above-mentioned embodiments mainly lies in that the present embodiment directly detects the pressure value in the cooking cavity 200, and uses the pressure value as the node for switching. In pressure cooking, the pressure change directly affects the cooking effect, so directly using pressure as the control core can more accurately ensure that the food is cooked at the correct pressure. On the other hand, some food materials are particularly sensitive to temperature changes, and using temperature as a control basis can more accurately maintain the cooking temperature and avoid the influence of excessively high or low temperature on the food.

[0104] For example, the initial power of the first heating state of the micro-pressure rice cooker can be set to 500W, and the capacity of the cooking cavity 200 is 3L. 1. Step S1, the first heating state heats the cooking cavity 200 at a heating power of 500W, when the real-time pressure P in the cooking cavity 200 rises to the switching pressure P0 (such as relative pressure 15KPa), enter step S2; switch to the second heating state, and after 20s (preset time t0) of continuous heating at 0W, the real-time pressure P is 17KPa, which does not reach 20KPa (pressure maintaining pressure P1), at this time the switching pressure P0 can be increased to 18KPa.

[0105] 2. Enter step S1, maintain the first heating state, when the real-time pressure P rises to the switching pressure P0, enter step S2; switch to the second heating state and continue for 20s (preset time t0), the real-time pressure P is 20KPa, reaches the pressure maintaining pressure P1, enters the pressure maintaining working phase.

[0106] In actual use, the switching pressure P0, the preset time t0 and the pressure maintaining pressure P1 are similar to the above-mentioned embodiments, and will not be described here.

[0107] In some embodiments, the pressure cooking appliance can directly detect the pressure within the cooking cavity 200 by a piezoelectric pressure sensor or a diaphragm pressure sensor.

[0108] The preferred embodiments of the present application have been described above with the aid of drawing provided only by way of example and therefore changes in form that do not clearly depart from the spirit of the present application are intended to be included. Therefore, the above- described embodiments are intended to be illustrative, and not restrictive, of the scope of the present application. Changes, such as great changes, in form and detail can be made without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A pressure control method for a pressure cooking appliance, characterized in that, Step S1: Maintain the first heating state, obtain the real-time temperature T inside the cooking chamber of the pressure cooking appliance, and if the real-time temperature T reaches the switching temperature T0, switch the heating device from the first heating state to the second heating state. The heating power of the first heating state is greater than the heating power of the second heating state. Step S2: Maintain the second heating state and determine whether the real-time temperature T reaches the pressure holding temperature T1 within the preset time t0; if so, enter the pressure holding stage. If not, increase the switching temperature T0, and ensure that the increased switching temperature T0 is not greater than the holding temperature T1, then return to step S1.

2. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: There are multiple temperature thresholds that are preset to increase sequentially, and the temperature threshold T0 for increasing the switching temperature is selected to be greater than the real-time temperature T.

3. The pressure control method for a pressure cooking appliance according to claim 2, characterized in that: The positive difference between adjacent temperature thresholds is the same.

4. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: The switching temperature T0 is increased to half the sum of the pressure holding temperature T1 and the real-time temperature T.

5. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: The initial switching temperature T0 is half the sum of the pressure-up temperature and the pressure-holding temperature T1.

6. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: The heating power in the second heating state is 0W.

7. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: Before returning to step S1, the heating power of the first heating state is reduced by the adjustment power ΔP.

8. The pressure control method for a pressure cooking appliance according to claim 7, characterized in that: The regulating power ΔP is a fixed value.

9. The pressure control method for a pressure cooking appliance according to claim 1, characterized in that: Before returning to step S1, the heating power of the first heating state is reduced by the adjustment power ΔP, and the preset time t0 is reduced by a preset value Δt each time.

10. A pressure control method for a pressure cooking appliance, characterized in that: Step S1: Maintain the first heating state, obtain the real-time pressure P in the cooking chamber of the pressure cooking appliance, and if the real-time pressure P reaches the switching pressure P0, switch the heating device from the first heating state to the second heating state. The heating power of the first heating state is greater than the heating power of the second heating state. Step S2: Maintain the second heating state and determine whether the real-time pressure P reaches the holding pressure P1 within the preset time t0; if so, enter the holding pressure stage. If not, increase the switching pressure P0, and ensure that the increased switching pressure P0 is not greater than the holding pressure P1, then return to step S1.

Images