Vehicle air conditioner defrosting control method, electronic equipment and computer readable storage medium

Abstract

The invention discloses a vehicle air conditioner defrosting control method, electronic equipment and a computer readable storage medium, and belongs to the technical field of vehicle air conditioner control. According to the defrosting control method, when a vehicle air conditioner is in a heating mode, the heating efficiency is guaranteed through a forward airflow path of an outdoor fan and an outdoor heat exchange unit; defrosting triggering conditions are accurately judged on the basis of air conditioner operation parameters and environment parameters, an outdoor fan reverse airflow mode is adopted in the last stage of a defrosting mode, residual defrosting water drops of an outdoor heat exchange unit are removed in a reverse blowing mode, secondary frosting is prevented, it is ensured that defrosting is thorough, and excessive energy consumption is avoided.

Description

Technical Field

[0001] This invention belongs to the field of vehicle air conditioning technology, specifically relating to a defrosting and de-icing control method for parking (RV) air conditioners or original vehicle air conditioners. Background Technology

[0002] A parking air conditioner is an air conditioner that operates while the vehicle is parked and waiting or resting, relying on a battery or other power source. It is mainly used in large vehicles such as trucks, RVs, and buses. It does not rely on the vehicle's engine for power and can be directly connected to the vehicle's battery. It can work normally even when the engine is off. It uses a DC 12V / 24V / 36V / 48V vehicle battery for power. The cooling system usually uses safe and environmentally friendly R134a or R410A refrigerant. The main structural forms are split type and integrated type. The integrated parking air conditioner is installed on the top of the cab, with a high degree of integration and no need for drilling.

[0003] If the RV air conditioner is a heat pump type, it can absorb heat from the outside in winter to generate heat. When heating, the outdoor heat exchange unit becomes the "heat absorption end". At this time, the surface temperature of the outdoor heat exchange unit will be much lower than the ambient temperature, sometimes as low as -20°C. Water vapor in the air will frost on its surface. The parking / RV air conditioner needs to defrost at this time, otherwise it will seriously hinder the heat exchange efficiency. If the frost layer continues to accumulate, it will further cause the component temperature to be too low, which may trigger the "low temperature protection" function of the air conditioner and force the air conditioner to shut down. Long-term frost may also damage core components such as the fan and compressor, shortening the life of the air conditioner.

[0004] Chinese utility model patent 202120781068.3 discloses a parking air conditioner, including a housing and a compressor, evaporator module, condenser module, and piping assembly respectively disposed inside the housing. The condenser 41 of the condenser module uses a tube-fin heat exchanger or a parallel-flow heat exchanger, and is arranged vertically or inclined. However, this vertical or inclined arrangement cannot effectively increase the heat dissipation area of ​​the condenser or effectively reduce the installation height. Existing integrated parking / RV air conditioners, in pursuit of high integration and small installation thickness, such as the parking air conditioner in Chinese utility model patent 202121462881.0, use a horizontally placed condenser, hoping to increase the horizontal dimension to reduce the overall installation height. However, in actual use, it has been found that the horizontally placed condenser requires frequent defrosting. During use, because the outdoor heat exchange unit frequently switches to defrost mode, the heating operation is interrupted, reducing the efficiency of the heating mode. Therefore, improving the defrosting efficiency in heating mode is particularly important for integrated parking air conditioners. Summary of the Invention

[0005] To address the above problems, this invention provides a vehicle air conditioning defrosting control method. To achieve the above objective, this invention provides the following technical solution: a vehicle air conditioning defrosting control method, comprising: the vehicle air conditioning entering a heating operation mode, with the outdoor fan positioned above the outdoor heat exchange unit, and airflow passing through the outdoor heat exchange unit before being discharged through the outdoor fan; acquiring vehicle air conditioning operating parameters or environmental parameters, and determining, based on the parameters, that predetermined conditions are met before entering a defrosting mode; at the end of the defrosting mode, the outdoor fan rotates in reverse and blows air towards the outdoor heat exchange unit; after the defrosting mode ends, the vehicle air conditioning re-enters the heating operation mode.

[0006] In this technical solution, the airflow direction of the outdoor fan during heating is specified, ensuring heat exchange efficiency by first passing through the outdoor heat exchange unit and then being discharged. At the end of defrosting, the outdoor fan rotates in the opposite direction to blow air towards the outdoor heat exchange unit, effectively removing residual defrost water droplets from the surface of the heat exchanger, preventing secondary frosting in low-temperature environments, improving defrosting thoroughness, and enhancing the defrosting effect and efficiency. This also improves the working efficiency of the heating mode, optimizes the switching operation between defrosting and heating modes, ensures rapid restoration of heating after defrosting, reduces temperature fluctuations inside the vehicle, and enhances the user experience.

[0007] More preferably, determining that the vehicle air conditioning operating parameters or environmental parameters meet the predetermined conditions includes one or more of the following: the compressor has been running continuously for a preset time; and / or, the outer ring temperature of T meets the preset value range, while the outer disc temperature of T meets the preset value range.

[0008] In the aforementioned preferred solution, a dual condition judgment is adopted based on "compressor continuous operating time" and / or "ambient temperature + external disk temperature." This prevents frequent defrosting in a short period, protecting components and reducing energy consumption, while ensuring timely defrosting when the frost layer reaches a certain thickness to avoid a decrease in heat exchange efficiency. It allows for triggering of "one or more" conditions, enabling flexible adjustment of the triggering logic according to different vehicle usage scenarios such as extreme low temperatures and high humidity environments, adapting to various climatic conditions. Moreover, by judging through preset parameters, complex calculations are unnecessary, reducing the computational load on the control system and improving response speed.

[0009] More preferably, determining that the vehicle's air conditioning operating parameters or environmental parameters meet predetermined conditions specifically includes: The compressor runs continuously for the preset time; And / or, the T outer ring and T outer disk of any of the following simultaneously satisfy the preset value range, specifically: -28℃≤T outer ring<-10℃ and T outer disk≤-16℃; -10℃≤T_outer ring<-5℃ and T_outer disk≤-13℃; -5℃≤T outer ring<0℃ and T outer disk≤-10℃; 0℃≤T_outer ring<6℃ and T_outer disk≤-7℃; T_outer ring > 6℃ and T_outer disk ≤ -2℃.

[0010] In this preferred technical solution, the outer ring (T) is divided into five intervals, corresponding to different threshold values. This precisely matches the frost risk at different temperatures; for example, the threshold is stricter in low-temperature, low-humidity environments, while it is more lenient in high-temperature, high-humidity environments, avoiding ineffective or untimely defrosting. The five intervals of the outer ring provide corresponding conditions for environments ranging from extremely cold (-28℃) to warm (>6℃), adapting to the usage needs of vehicles in different regions and seasons, making it particularly suitable for vehicles such as RVs and trucks that need to travel across regions. The clearly defined temperature ranges allow for quantifiable execution of the control logic, facilitating engineering implementation and parameter tuning, and improving the stability of the air conditioning system.

[0011] More preferably, the defrosting mode executes at least the following sequence: compressor shutdown, four-way valve reversal, compressor startup and speed adjustment, and outdoor fan backflushing.

[0012] The defrosting mode specifically includes: compressor shutdown and outdoor fan shutdown; the four-way valve reversing after a predetermined interval; the indoor fan stopping when the T-panel temperature drops to the preset value; the compressor starting after a predetermined time after the defrosting mode begins; the compressor first running at high speed, then slowing down, and finally stopping, while the outdoor fan reverses its direction for a predetermined time; thus completing the defrosting mode.

[0013] In this preferred technical solution, timing control provides buffer time for actions such as four-way valve reversal and compressor startup, ensuring coordinated operation of all components and preventing compressor startup before the four-way valve is fully reversed, thus reducing mechanical losses. By stopping the indoor fan when the T-panel temperature drops to a predetermined value, cold air is avoided during defrosting, which is particularly suitable for the heating needs of enclosed spaces in vehicles, improving user comfort. Furthermore, a predetermined time for the outdoor fan to reverse operation is specified, specifically addressing the issue of water accumulation on the heat exchanger surface after defrosting, preventing secondary frosting, and reducing defrosting frequency.

[0014] More preferably, after entering defrost mode, when: the external coil temperature is higher than the preset temperature; and / or the cumulative defrost time reaches the preset time; the compressor will reduce its frequency and run for a predetermined time before stopping. This avoids system pressure fluctuations caused by sudden compressor shutdown, protects the compressor and reduces noise, and ensures that residual heat on the heat exchanger surface is fully dissipated. Therefore, the combination of these two parameters ensures thorough defrosting while avoiding energy waste and vehicle interior cooling caused by excessive defrosting.

[0015] This application also protects an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the aforementioned vehicle air conditioning defrosting control method.

[0016] This application also protects a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the vehicle air conditioning defrosting control method according to any one of the preceding claims.

[0017] The beneficial effects of this application will be further explained in specific embodiments. Attached Figure Description

[0018] Figure 1 This is a perspective view of the parking air conditioner in this invention after part of the upper cover has been removed; Figure 2 This is a view of the parking air conditioner in this invention after part of the upper cover and one side outdoor fan have been removed; Figure 3 For the present invention Figure 1 Top view; Figure 4 For the present invention Figure 1 Side view; Figure 5 For the present invention Figure 1 A bottom view; Figure 6 This is a flowchart of the vehicle air conditioning defrosting control method of the present invention.

[0019] In the diagram: 1. Base; 2. Indoor heat exchange unit; 3. Indoor fan; 4. Compressor; 5. Outdoor heat exchange unit; 6. Outdoor air inlet; 7. Outdoor fan; 8. Indoor air outlet; 9. Indoor air inlet; 10. Frame. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The parking air conditioner operates on the same principle as a conventional air conditioner. An indoor heat exchange unit 2, an indoor fan 3, a compressor 4, an outdoor heat exchange unit 5, an expansion valve, and a controller are installed on the base 1, forming a heat pump circulation system. The indoor heat exchange unit 2 and the outdoor heat exchange unit 5 can be selectively used as condensers or evaporators, respectively. When the indoor heat exchange unit 2 acts as a condenser, the parking air conditioner operates in heating mode; when it acts as an evaporator, it operates in cooling mode. The frame 10 is located in the driver's cab and integrates an indoor air outlet 8 and an indoor air inlet 9. On the outdoor side, due to the action of the outdoor fan 7, airflow from the outside environment is introduced through the outdoor air inlet 6, passes upwards through the outdoor heat exchange unit 5, and is further discharged upwards from the outdoor fan 7, completing the heat exchange between the outdoor air and the heat exchanger.

[0022] For roof-mounted integrated parking air conditioners, the installation method of the heat exchanger directly affects the overall thickness, heat exchange efficiency, and condensate drainage safety. Furthermore, in the air conditioning system, the outdoor heat exchanger is larger than the indoor heat exchanger, and its installation method has a greater impact on the overall height. Existing technologies often use vertical or inclined installation of the outdoor heat exchanger, which increases the overall height. However, in this embodiment, the outdoor heat exchanger 5 is placed horizontally.

[0023] In actual use, the applicant found that when switching from heating mode to defrost mode, the outdoor heat exchange unit 5, which is placed horizontally, is heated, and the frost on it melts into water droplets. However, due to the upward airflow from the outdoor fan 7 above, these water droplets cannot fall effectively due to their own gravity and thus remain on the heat exchanger. When the heating mode is switched back on, these water droplets turn back into frost. This forces the integrated parking air conditioner to frequently enter defrost mode.

[0024] Therefore, this embodiment provides a method for using the outdoor fan 7 to blow the melted water from the outdoor heat exchange unit 5 downwards during defrosting, and then switching to heating mode. By switching operating conditions and precise temperature control, the harmful effects of frost formation are avoided, thereby optimizing the defrosting mode. Details are as follows: The vehicle's air conditioning is in heating mode; determine whether to enter defrost mode. Defrost entry conditions are divided into "time-based judgment" and "temperature-based judgment": Time condition judgment Taking a 45-minute interval as an example, defrosting is only allowed to be triggered when the compressor has been running continuously for 45 minutes during heating, or when there has been a 45-minute interval since the last defrost cycle, rather than defrosting whenever the temperature condition is met. In the early stages of heating with a heat pump air conditioner, although the outdoor heat exchanger temperature is low, the frost layer has not yet formed a significant layer. If defrosting is frequently triggered at this time, it will cause heating interruption, large fluctuations in the vehicle's interior temperature, and frequent compressor start-stop cycles, increasing energy consumption and component wear.

[0025] Preferably, within a 45-minute heating cycle, heating is maintained for 40 minutes. If the conditions are met, a further 5-minute wait is required to trigger the defrost mode. Even if both time and temperature conditions are met simultaneously, defrosting should only begin after 40 minutes of continuous heating. This avoids false triggering caused by sudden temperature fluctuations, such as a brief drop in outdoor temperature causing the exterior of the T-shaped heating element to meet the requirements, but without actual frost formation. The 5-minute buffer period verifies the stability of the frost layer, ensuring that the defrosting action is necessary and effective.

[0026] Temperature condition judgment Under different outdoor ambient temperatures (T_outer ring), the water vapor content in the air varies, and the critical temperature for frost formation (T_outer plate), i.e., the outdoor heat exchanger coil temperature, also varies. In this embodiment, T_outer ring is divided into 5 intervals, corresponding to different T_outer plate thresholds: Temperature range 1: -28℃≤T outer ring<-10℃, and T outer disk≤-16℃. In low-temperature environments (below -10℃), the water vapor content in the air is low, and the frost layer forms slowly and thinly. Therefore, the T outer disk threshold is lower (-16℃), avoiding unnecessary defrosting; at the same time, it covers extremely cold regions (-28℃), adapting to the complex low-temperature outdoor scenarios of RVs.

[0027] Temperature range 2: -10℃≤T outer ring<-5℃, and T outer disk≤-13℃. Compared with the aforementioned temperature range, this temperature is slightly higher, the water vapor content in the air is slightly increased, and the risk of frost formation is increased. Therefore, the T outer disk threshold is increased (-13℃) to ensure that defrosting is triggered as soon as the frost layer accumulates to the point of affecting heat exchange.

[0028] Temperature range 3: -5℃≤T outer ring<0℃, and T outer plate≤-10℃, close to 0℃ low temperature and high humidity zone, such as rainy or snowy days, the water vapor content is high and the frost speed is fast. The T outer plate threshold is further increased (-10℃) to trigger defrosting in advance and avoid the frost layer from quickly clogging the condenser.

[0029] Temperature range 4: 0℃≤T outer ring<6℃, and T outer disk≤-7℃. The higher the temperature, the more active the water vapor, and the highest risk of frost formation. The frost layer is more likely to turn into "wet frost", so it accumulates faster. The highest threshold of T outer disk (-7℃) can block the spread of frost layer in time.

[0030] Temperature range 5: T outer ring is above 6℃ and T outer plate is ≤-2℃. The environment above 6℃ is close to the "non-frost zone". Frost may only form when the condenser temperature is extremely low (≤-2℃). The threshold is lenient to avoid false triggering. At this time, it is more likely to be condensate rather than frost.

[0031] Defrosting Procedure The defrosting process mainly consists of the following steps: compressor shutdown → four-way valve reversal → compressor startup → compressor speed adjustment → residual water treatment, i.e., the "preparation first, defrosting second, and finalization third" approach.

[0032] 1) During the defrosting cycle, the compressor and external fan are shut down. When the compressor is running, reversing can easily cause high-pressure impact and damage to the valve body. Therefore, the compressor is stopped to prepare for the subsequent reversing of the four-way valve. At the same time, the outdoor fan is stopped to prevent cold outdoor air from continuously blowing onto the condenser, which would affect the subsequent defrosting efficiency. Defrosting requires the condenser to release heat, and stopping the outdoor fan can reduce heat loss.

[0033] 2) The four-way valve reverses 35 seconds after defrosting begins. The four-way valve reversing is the core step in switching the air conditioner to a different mode, from heating mode to defrost mode (which is essentially the same as the air conditioner's cooling mode; in this mode, the indoor heat exchange unit absorbs heat, and the outdoor heat exchange unit releases heat, directly melting the surface frost). After the compressor stops, the system's high and low pressures need to balance briefly. During this time, the four-way valve reversing is smoother, avoiding valve body wear. Therefore, 35 seconds after defrosting begins, time is given for pressure balance after the compressor stops.

[0034] 3) When the temperature of the internal coil is <20℃, the internal fan will stop. In the initial stage of the reversal, the indoor heat exchange unit becomes the "heat absorption end" and the temperature will drop. If the indoor fan continues to run, it will blow cold air into the driver's cab. Stopping the indoor fan can avoid the temperature drop inside the vehicle during defrosting, which is especially suitable for the scenario where the heating needs of the small space of the RV are sensitive. In this embodiment, when the temperature of the inner coil is >20°C, even if cold air is blown, it will not be obvious. The fan will only stop when the temperature is below 20°C, so the shutdown time can be reasonably controlled.

[0035] 4) The compressor will start operating 1 minute after the defrosting cycle begins. The compressor starts operating one minute after the defrosting cycle begins, allowing sufficient time for the four-way valve to switch. The four-way valve requires mechanical action time to switch from the "heating" position to the "cooling" position. The one-minute delay ensures that the switching is fully completed, preventing "gas leakage" in the system when the compressor starts and protecting the compressor motor.

[0036] 5) Run the press at its highest speed for 4 minutes, then reduce the speed to 2 / 3 of its maximum. Initially, the frost layer is thick and requires strong heat release. The compressor should be run at its highest speed for 4 minutes. At the highest speed, the compressor outputs a larger flow of high-temperature refrigerant, and the condenser has a higher heat release power, which can quickly melt the thick frost layer. After that, the speed should be reduced to 2 / 3 of the speed to reduce energy consumption and at the same time avoid the condenser temperature from getting too high, preventing the fins from overheating and being damaged.

[0037] 6) After defrosting is complete, the compressor stops → after 30 seconds, the outdoor fan reverses direction for 20 seconds. The compressor should be stopped first to avoid system pressure fluctuations when the external fan starts, thus protecting the compressor. Reversing the operation of the external fan is the core "finishing action". After defrosting, water droplets will remain on the surface of the condenser. If not treated, they are prone to refreezing at low temperatures, forming "secondary frost". Reversing the operation can blow the water droplets away from the fins, completely eliminating the risk of secondary frost, making it suitable for the low-temperature outdoor environment of RVs and avoiding repeated defrosting.

[0038] 7) 60 seconds after defrosting ends, the four-way valve will operate and the compressor will start to resume heating. ① Allow sufficient time for the external fan to reverse, i.e., 20 seconds for water blowing + 40 seconds for shutdown buffer; ② Allow sufficient mechanical action time for the four-way valve to switch from the "cooling position" to the "heating position" to avoid system pressure imbalance when the compressor starts; Therefore, the compressor should be restarted after the system is switched on to ensure that the system is stable before resuming heating, thus avoiding the user's feeling of "sudden changes in temperature" and protecting the compressor.

[0039] In summary, a defrosting cycle takes about 7 minutes. 7 minutes is the normal and reasonable defrosting time for heat pump air conditioners. It is enough to melt a medium-thickness frost layer to avoid incomplete defrosting, and it will not cause the temperature inside the car to drop excessively due to excessive time.

[0040] Defrosting Exit Conditions The defrost termination condition uses a dual logic of either temperature or time thresholds to avoid insufficient or excessive defrosting. Defrosting withdrawal condition 1: External coil temperature > 12℃ 12℃ is the safe threshold for no frost residue. At this temperature, the condensate will not freeze, and after the frost melts, the surface temperature of the condenser will quickly rise from a negative value to above 12℃. Defrosting exit condition 2: Total defrosting time 6 minutes If a sensor malfunctions, such as a failure of the T-disk sensor, and cannot detect a temperature rise, causing the temperature conditions not to be triggered, the 6-minute time threshold can forcibly terminate defrosting to avoid indefinite or excessive defrosting. Otherwise, it will cause a sudden drop in the vehicle's interior temperature and prolonged high-load operation of the compressor, increasing energy consumption and component wear.

[0041] Preferably, after the standard is met, the compressor will run at a reduced frequency for 1 minute before shutting down. Even if the temperature or time meets the standard, the compressor will not shut down directly, but will run at a reduced frequency for 1 minute. The purpose is to completely remove excess heat, avoid residual high-temperature refrigerant in the condenser, prevent a sudden increase in system pressure when heating is resumed, and ensure that residual moisture on the condenser surface is fully evaporated, further reducing the risk of secondary frosting.

[0042] It should be noted that the specific parameter values ​​given in this embodiment should not be construed as limiting the claims, but are used to illustrate the feasibility of the technical solution given in this embodiment.

[0043] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vehicle air conditioning defrosting control method, characterized in that, include: When the vehicle's air conditioning enters the heating mode, the outdoor fan is located above the outdoor heat exchange unit, and the airflow first passes through the outdoor heat exchange unit and then is discharged through the outdoor fan. Obtain vehicle air conditioning operating parameters or environmental parameters, and enter defrost mode after determining that the predetermined conditions are met based on the parameters; At the end of the defrosting mode, the outdoor fan rotates in reverse and blows air towards the outdoor heat exchange unit; After the defrosting mode ends, the vehicle's air conditioning will switch back to heating mode.

2. The vehicle air conditioning defrosting control method according to claim 1, characterized in that, Determining that the vehicle's air conditioning operating parameters or environmental parameters meet predetermined conditions includes one or more of the following: The compressor runs continuously for a preset time X1; And / or, the outer ring temperature of T meets the preset value range ΔT1, and the outer disk temperature of T meets the preset value range ΔT2.

3. The vehicle air conditioning defrosting control method according to claim 1, characterized in that, Determining whether the vehicle's air conditioning operating parameters or environmental parameters meet the predetermined conditions specifically includes: The compressor runs continuously for a preset time X1; And / or, the T outer ring and T outer disk of any of the following simultaneously satisfy the preset value range, specifically: -28℃≤T outer ring<-10℃ and T outer disk≤-16℃; -10℃≤T_outer ring<-5℃ and T_outer disk≤-13℃; -5℃≤T_outer ring<0℃ and T_outer disk≤-10℃; 0℃≤T_outer ring< 6℃ and T_outer disk≤-7℃; T_outer ring > 6℃ and T_outer disk ≤ -2℃.

4. The vehicle air conditioning defrosting control method according to claim 1, characterized in that, The defrosting mode executes at least the following sequence: compressor shutdown, four-way valve reversal, compressor startup and speed adjustment, and outdoor fan backflushing.

5. The vehicle air conditioning defrosting control method according to claim 4, characterized in that, The defrost modes specifically include: Compressor shutdown and outdoor fan shutdown; The four-way valve reverses after a predetermined interval x2. When the temperature of the inner panel T drops to the preset value T3, the indoor fan stops. The compressor starts three preset times after the defrost mode begins. The compressor first runs at high speed, then slows down, and finally stops. Outdoor fan reverse rotation scheduled time x4; Defrosting mode complete.

6. The vehicle air conditioning defrosting control method according to claim 1, characterized in that, After entering defrost mode, If 1) the external coil temperature is higher than the preset temperature T4; and / or 2) the cumulative defrosting time reaches the preset time X5; The compressor will then reduce its frequency and run for a predetermined time of x6 before shutting down.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the vehicle air conditioning defrosting control method of any one of claims 1-6.

8. A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the vehicle air conditioning defrosting control method according to any one of claims 1-6.

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