Self-cleaning control method for a pickup truck air conditioner

Abstract

The application discloses a self-cleaning control method for a pickup truck air conditioner. When starting self-cleaning, the original temperature sensor protection function of the core body is automatically cut off to prevent triggering the automobile air conditioner self-core protection logic start and blocking the self-cleaning process. After starting self-cleaning, the frost thickness monitoring and setting time are used to feedback the frost degree of the core body, the compressor speed is controlled through the frost rate, the vehicle energy consumption in the self-cleaning process is effectively reduced, and the damage of the core body in the repeated self-cleaning process is avoided. When defrosting and dust removing, the bidirectional heating principle is adopted to realize the purpose of quickly melting the frost on the core body, the dust and particulate matters on the evaporator core body can be effectively reduced, and the self-cleaning purpose of the automobile air conditioner is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pickup truck air conditioners, in particular to a self-cleaning control method for a pickup truck air conditioner. BACKGROUND

[0002] When the pickup truck is driven in off-road conditions, the environment it faces is relatively harsh, and dust, dirt, etc. are easy to accumulate on the surface of the pickup truck air conditioner evaporator core. Especially in the summer high temperature environment, the dust and dirt accumulated on the surface of the pickup truck air conditioner evaporator core is more likely to breed bacteria, mold, etc. on the surface of the core. After the particulate matter accumulates to a certain thickness, it will ferment on the surface of the core and become a source of odor in the vehicle. How to solve the problem of self-cleaning of the automobile air conditioner has always been a research focus and hotspot in the field.

[0003] In the prior art, Chinese invention patent CN113085482A discloses a method for self-cleaning of dust on the surface of an air conditioner evaporator by frosting, defrosting and air drying. However, the prior art solution cannot effectively control the speed of the compressor in real time, which is easy to cause waste of vehicle energy and is not conducive to energy saving and environmental protection. At the same time, the prior art solution cannot accurately determine the frost layer thickness of the core, which is easy to cause the defrosting time to be too long and the temperature in the vehicle to change too much; and for small vehicle air conditioners using parallel flow cores, if the frost layer thickness of the core cannot be accurately determined, the frost layer of the core will be too thick, which will cause the partial brazing position of the core to fall off, thereby causing irreversible damage to the evaporator core. SUMMARY

[0004] The present application aims to provide a self-cleaning control method for a pickup truck air conditioner.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution:

[0006] The self-cleaning control method for a pickup truck air conditioner disclosed by the present application adopts an air conditioning system composed of a compressor, a controller, an electronic expansion valve, an evaporator, a condenser, a condenser fan and an evaporator surface electric heating wire, comprising the following steps,

[0007] S1, rapid refrigeration;

[0008] After entering the self-cleaning mode, the evaporator core temperature protection logic is disconnected, the electronic expansion valve opening degree is adjusted to a first preset opening degree, the condenser fan speed is increased to a first preset speed, the compressor frequency remains unchanged, the evaporator blower speed is reduced by one step, and rapid refrigeration is realized.

[0009] S2, forming a frost layer;

[0010] Real-time acquisition of the frost thickness of the evaporator core fin, calculation of the growth rate of the frost thickness; when the growth rate is greater than 0 and less than or equal to a first preset value, the electronic expansion valve is controlled to reduce the opening degree to a second preset opening degree at a linear rate, the condenser fan speed is reduced to a second preset speed, and the compressor speed is unchanged, until the frost thickness meets the requirements, and the operation state is maintained for a certain time;

[0011] S3, defrosting and dust removal;

[0012] The electric heating wire is started, the electronic expansion valve is controlled to reduce the opening degree to a third preset opening degree at a linear rate, the compressor is reduced to a first preset frequency, the condenser fan speed is reduced to a third preset speed, the inner circulation air door is closed, and the outer circulation air door is opened, until the frost thickness of the evaporator core fin is 0, then the evaporator blower is controlled to run at the lowest speed for a preset drainage time, the electric heating wire and the outer circulation air door are closed, and the normal refrigeration mode is entered.

[0013] Further, the evaporator core temperature protection logic is that when the evaporator core temperature sensor detects that the evaporator core temperature decreases to 2℃, the compressor stops working, and when the evaporator core temperature sensor detects that the evaporator core temperature increases to 5℃, the compressor starts.

[0014] Further, the frost thickness is monitored in real time by a plurality of frost thickness sensors installed at different positions of the evaporator core fin, and the actual frost thickness is determined by the maximum monitoring value.

[0015] Further, the frost thickness sensor only starts to work after the self-cleaning module is started, so as to reduce the number of circuit ports used.

[0016] Further, the frost thickness meets the requirements when the frost thickness growth rate is 0 or the frost thickness reaches a preset thickness.

[0017] Further, in S1, if the evaporator core temperature protection logic is not disconnected, an alarm is given and the execution is terminated until the alarm is eliminated.

[0018] Further, in S3, after detecting that the frost thickness is 0, the drainage time is entered, and the evaporator blower is reduced to the lowest speed to run, so that the condensed water on the core surface can quickly and effectively drip under the action of gravity, achieving the purpose of efficient cleaning of the core surface, and avoiding that the water in the water box cannot be normally discharged due to the negative pressure formed by the too large air speed of the blower.

[0019] The advantage of the present application is that when starting the self-cleaning, the original temperature sensor protection function of the core body is automatically cut off to prevent triggering the car air conditioner core body protection logic to start and block the self-cleaning process. After starting the self-cleaning, the frost thickness monitoring and setting time are used to feedback the frosting degree of the core body, and the compressor speed is controlled through the frosting rate, which effectively reduces the energy consumption of the whole vehicle during the self-cleaning process, and avoids the damage of the core body in the repeated self-cleaning process. In the defrosting and dust removal process, the bidirectional heating principle is adopted to achieve the purpose of rapid melting of the frost on the core body, which can effectively reduce the dust and particulate matter on the evaporator core, and achieve the self-cleaning purpose of the car air conditioner. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the air conditioning system diagram of the car.

[0021] Figure 2 is the internal wind field flow direction diagram of the cab of the car.

[0022] Figure 3 is the flow chart of the method described in the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] As shown in Figure 1 , Figure 2 , the air conditioning system diagram used in the self-cleaning control method for the air conditioner of the pickup truck described in the present application is shown, wherein 1 is the compressor of the air conditioning system, 2 is the condenser fan, 3 is the condenser assembly, 4 is the electronic expansion valve, and 5 is the evaporator assembly. The evaporator assembly 5 is composed of a blower 9 and an evaporator core 10. Figure 2 In the internal wind field flow direction diagram of the cab, 7 is the internal circulation air door, which is opened only when the internal circulation function of the cab is opened. 8 is the external circulation air door, which is opened only when the external circulation function of the cab is opened. The internal circulation air door 7 and the external circulation air door 8 cannot be opened at the same time. Figure 2 In the evaporator core 10, 11 is a frost thickness sensor installed on the evaporator core 10. 12 is an electric heating wire installed on the surface of the evaporator.

[0025] Based on the above-mentioned air conditioning system, the self-cleaning control method for the air conditioner of the pickup truck described in the present application specifically includes the following steps:

[0026] S1, rapid refrigeration;

[0027] Due to vehicle driving environment and prolonged use of the air conditioning system, a large amount of dust and dirt easily accumulates on the evaporator core 10, requiring cleaning. At this time, the user can activate the self-cleaning module via the center console, or the system can automatically determine whether the conditions for activating the self-cleaning mode have been met. After entering self-cleaning mode, the evaporator core 10 temperature protection logic used during normal air conditioning operation must first be disconnected. According to the evaporator core 10 temperature protection logic during normal air conditioning operation: when the evaporator core 10 temperature sensor detects that the evaporator core 10 temperature has dropped to 2℃, the compressor stops working; when the evaporator core 10 temperature sensor detects that the evaporator core 10 temperature has risen to 5℃, the compressor starts. Because the self-cleaning process can easily trigger the evaporator core 10 temperature protection logic used during normal air conditioning operation, failing to disconnect or disable the evaporator core 10 temperature protection logic will affect the normal operation of the self-cleaning mode. In this invention, if the temperature signal of the evaporator core 10 can still be detected and received after entering the self-cleaning mode, it indicates that the temperature protection logic of the evaporator core 10 has not been disconnected or shielded. An alarm will be triggered and the execution of subsequent steps will be terminated. The subsequent self-cleaning method steps can only continue after the alarm fault is cleared.

[0028] After the evaporator core 10 temperature protection logic is disconnected during normal air conditioner operation, the vehicle control system will control the electronic expansion valve 4, condenser fan 2, and blower 9 to increase heat exchange and achieve rapid cooling. Specifically, the electronic expansion valve 4 is adjusted to a first preset opening, the condenser fan 2 speed is increased to a first preset speed to increase system heat dissipation, the compressor 1 frequency remains unchanged, and the blower 9 in the evaporator 5 operates at a reduced speed. Through these operations, rapid cooling is achieved, increasing the system's heat exchange.

[0029] S2, forms a frost layer;

[0030] The frost thickness of the evaporator core 10 is monitored in real time by several frost thickness sensors 11 installed at different positions on the fins of the evaporator core 10. The actual frost thickness of the evaporator core 10 is determined by the maximum value among all the monitored values. The maximum value can be the value of the largest frost thickness among all monitored values, or the value of the point where the frost thickness increases at the highest rate among all monitored values.

[0031] The vehicle controller acquires the frost thickness in real time and calculates the frost thickness growth rate. When the frost thickness growth rate is greater than a first preset value, the current operating state of the air conditioning system remains unchanged. When the frost thickness growth rate is greater than 0 and less than or equal to the first preset value, the opening of the electronic expansion valve 4 and the speed of the condenser fan 2 are controlled until the frost thickness reaches the target and is maintained for a certain period of time. The determination that the frost thickness reaches the target can be based on the frost thickness growth rate being 0 or the frost thickness on the surface of the evaporator core 10 reaching the preset thickness value.

[0032] Specifically, the electronic expansion valve 4 reduces its opening to a second preset opening at a first linear rate. After the electronic expansion valve 4 reduces its opening to the second preset opening, the condenser fan 2 speed decreases to the second preset speed to reduce vehicle energy consumption. The compressor 1 frequency remains unchanged. Then, the air conditioning system operates under this condition until the frost thickness growth rate reaches 0 or the frost thickness of the evaporator core 10 reaches a preset thickness. After that, the electronic expansion valve 4 is maintained at its current opening to allow the system to run for a certain period of time, so that dust and dirt on the surface of the evaporator core 10 adhere to the frost surface to the maximum extent. At the same time, the condenser fan 2 speed and the compressor 1 frequency are maintained at the same operating time.

[0033] It should be noted that the frost thickness sensor 11 only starts working after the self-cleaning module is activated. At other times, the frost thickness sensor 11 is in a static state and does not send signals, in order to reduce the number of circuit ports used.

[0034] S3, defrost and dust removal;

[0035] When the frost thickness growth rate reaches 0, or the frost thickness on the evaporator core 10 reaches a preset thickness and remains in the current operating state for a certain period of time, the rapid defrosting, dust removal, and self-cleaning step will begin. Specifically, the electric heating wire 12 is activated, the electronic expansion valve 4 is controlled to reduce its opening at a second linear rate to a third preset opening, the compressor 1 is reduced to a first preset frequency, the condenser fan 2 is reduced to a third preset speed, the internal circulation damper 7 is closed, and the external circulation damper 8 is opened to introduce high-temperature ambient air into the evaporator core 10, thereby achieving rapid defrosting until the frost thickness on the surface of the evaporator core 10 is 0. After that, the drainage and dust removal stage begins. At this time, the blower 9 in the evaporator 5 is controlled to operate at the lowest speed, facilitating the rapid and effective dripping of condensate from the frost layer on the surface of the evaporator core 10 under the action of gravity. This also ensures that condensate mixed with dust and particles on the surface of the evaporator core 10 is quickly discharged from the drain box in the evaporator assembly. This not only achieves efficient cleaning of the evaporator core surface but also prevents water from flowing into the drain box and creating negative pressure due to excessive blower speed, which would prevent the water in the drain box from draining properly. After maintaining this state until the preset drainage time, the electric heating wire 12 is turned off, the external circulation damper is closed, and the air conditioning system returns to its pre-self-cleaning operating state, entering normal cooling mode.

[0036] like Figure 3 As shown, the specific implementation process of the self-cleaning control method for the evaporator core used in automotive air conditioning according to the present invention is described as follows:

[0037] After the self-cleaning mode is activated, it checks whether the temperature sensor signal of the evaporator core 10 is disconnected / shielded. If it is not disconnected / shielded, an alarm is triggered. After the alarm is cleared, it checks again whether the temperature sensor signal of the evaporator core 10 is disconnected / shielded. If the temperature sensor signal of the evaporator core 10 is disconnected, it enters the rapid cooling stage. The opening of the electronic expansion valve 4 is adjusted to the first preset opening, the speed of the condenser fan 2 is increased to the first preset speed, the frequency of the compressor 1 remains unchanged, and the blower speed in the evaporator 5 is reduced by one level to achieve rapid cooling.

[0038] The frost thickness of the evaporator core 10 is detected in real time, and the relationship between the frost thickness of the evaporator core 10 and the set rate is determined. When the growth rate of the frost thickness is greater than the first preset value, the current operating state of the air conditioning system remains unchanged, the frost thickness of the evaporator core 10 is detected, and the relationship between the frost thickness of the evaporator core 10 and the set rate is determined.

[0039] When the rate of increase of the frost layer thickness is greater than 0 and less than or equal to the first preset value, the electronic expansion valve 4 reduces its opening to the second preset opening at the first linear rate. After the electronic expansion valve 4 reduces its opening to the second preset opening, the speed of the condenser fan 2 is reduced to the second preset speed to reduce vehicle energy consumption. The frequency of the compressor 1 remains unchanged. Then, the air conditioning system operates under this operating condition and detects the actual frost layer thickness of the evaporator core 10 in real time again to determine the relationship between the frost layer thickness of the evaporator core 10 and the set rate.

[0040] When the frost thickness growth rate is 0 or the frost thickness of the evaporator core 10 reaches the preset thickness, the current state of the system is maintained to allow the system to run for a certain period of time, so that the dust and dirt on the surface of the evaporator core 10 can adhere to the frost surface to the maximum extent.

[0041] Then, the electric heating wire 12 is activated, and the electronic expansion valve 4 is controlled to reduce its opening to the third preset opening at a linear rate. The compressor 1 is reduced to the first preset frequency, and the condenser fan 2 is reduced to the third preset speed. At the same time, the internal circulation damper 7 is closed and the external circulation damper 8 is opened. The frost layer thickness of the evaporator core 10 is detected in real time, and it is determined whether the frost layer thickness is 0.

[0042] Once the frost layer thickness reaches 0, reduce the speed of blower 9 to the lowest setting. Determine whether to maintain this state until the preset drainage time is met. If the preset drainage time is met, turn off electric heating wire 12, close the external circulation damper, and enter normal cooling mode.

Claims

1. A self-cleaning control method for a pickup truck air conditioner, comprising an air conditioning system consisting of a compressor, a controller, an electronic expansion valve, an evaporator, a condenser, a condenser fan, and an electric heating wire on the evaporator surface, characterized in that: Includes the following steps, S1, rapid cooling; After entering self-cleaning mode, the evaporator core temperature protection logic is disconnected, the opening of the electronic expansion valve is adjusted to the first preset opening, the condenser fan speed is increased to the first preset speed, the compressor frequency remains unchanged, and the blower speed in the evaporator is reduced by one level to achieve rapid cooling. The evaporator core temperature protection logic is as follows: when the evaporator core temperature sensor detects that the evaporator core temperature drops to 2°C, the compressor stops working; when the evaporator core temperature sensor detects that the evaporator core temperature rises to 5°C, the compressor starts. S2, forms a frost layer; The frost layer thickness of the evaporator core fins is acquired in real time, and the growth rate of the frost layer thickness is calculated. When the growth rate is greater than 0 and less than or equal to a first preset value, the electronic expansion valve is controlled to reduce its opening to a second preset opening at a linear rate, the condenser fan speed is reduced to a second preset speed, and the compressor speed remains unchanged until the frost layer thickness meets the requirements, and then the operation is maintained for a certain period of time. S3, defrost and dust removal; Start the electric heating wire, control the electronic expansion valve to reduce the opening to the third preset opening at a linear rate, reduce the compressor frequency to the first preset frequency, reduce the condenser fan speed to the third preset speed, close the internal circulation damper, open the external circulation damper, until the frost layer thickness of the evaporator core fins is 0, control the blower in the evaporator to run at the lowest speed until the preset drainage time, then turn off the electric heating wire and the external circulation damper, and enter the normal cooling mode; Specifically: The system continuously monitors the frost thickness of the evaporator core, determines the relationship between the frost thickness and the set rate, and maintains the current operating state of the air conditioning system unchanged when the frost thickness increases at a rate greater than the first preset value. It continues to monitor the frost thickness of the evaporator core and determines the relationship between the frost thickness and the set rate. When the rate of increase of the frost thickness is greater than 0 and less than or equal to the first preset value, the electronic expansion valve reduces its opening to the second preset opening at the first linear rate. After the electronic expansion valve opening is reduced to the second preset opening, the condenser fan speed is reduced to the second preset speed to reduce vehicle energy consumption. The compressor frequency remains unchanged. Then, the air conditioning system works under this operating condition and detects the actual frost thickness of the evaporator core in real time again to determine the relationship between the frost thickness of the evaporator core and the set rate. When the frost thickness growth rate is 0 or the frost thickness of the evaporator core reaches the preset thickness, the system is maintained in its current state for a certain period of time to allow dust and dirt on the surface of the evaporator core to adhere to the frost surface to the maximum extent.

2. The self-cleaning control method for pickup truck air conditioning according to claim 1, characterized in that: The frost thickness is monitored in real time by several frost thickness sensors installed at different positions on the evaporator core fins, and the actual frost thickness is determined by the maximum monitored value.

3. The self-cleaning control method for pickup truck air conditioning according to claim 2, characterized in that: The frost thickness sensor only starts working after the self-cleaning module is activated, in order to reduce the number of circuit ports used.

4. The self-cleaning control method for pickup truck air conditioning according to claim 1, characterized in that: The frost layer thickness must meet the following requirements: the frost layer thickness growth rate is 0 or the frost layer thickness reaches a preset thickness.

5. The self-cleaning control method for pickup truck air conditioning according to claim 1, characterized in that: In step S1, if the evaporator core temperature protection logic is not disconnected, an alarm will be triggered and execution will be terminated until the alarm is cleared.

6. The self-cleaning control method for pickup truck air conditioning according to claim 1, characterized in that: In step S3, once the frost thickness is detected to be 0, the drainage time begins immediately. The blower in the evaporator is reduced to the lowest speed to facilitate the rapid and effective dripping of condensate on the core surface under the action of gravity, achieving the purpose of efficient cleaning of the core surface and avoiding the formation of negative pressure due to excessive blower speed, which would prevent the water in the water box from being discharged normally.

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