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] This invention relates to the field of pickup truck air conditioning, and more particularly to a self-cleaning control method for pickup truck air conditioning. Background Technology

[0002] When pickup trucks operate in off-road conditions, they face harsh environments, making it easy for dust and dirt to accumulate on the surface of the evaporator core of the air conditioning system. Especially in the high temperatures of summer, this accumulated dust and dirt can easily breed bacteria and mold on the surface of the evaporator core. Once the particulate matter accumulates to a certain thickness, it can ferment on the surface of the core, becoming a source of unpleasant odors inside the vehicle. How to solve the problem of self-cleaning in automotive air conditioning systems has always been a key research focus and hot topic in this field.

[0003] In the prior art, Chinese invention patent CN113085482A discloses a method for self-cleaning dust on the surface of an air conditioner evaporator by using frosting, defrosting, and air drying. However, the existing technical solution cannot effectively control the compressor speed in real time, which can easily lead to energy waste in the vehicle and is not conducive to energy conservation and environmental protection. At the same time, the existing technical solution cannot accurately judge the thickness of the frost layer on the core, which can easily lead to excessively long defrosting time and excessive temperature changes inside the vehicle. Moreover, for small car air conditioners using parallel flow cores, if the thickness of the frost layer on the core cannot be accurately judged, resulting in an excessively thick frost layer on the core, it can cause the brazing positions on the core to fall off, thereby causing irreversible damage to the evaporator core. Summary of the Invention

[0004] The purpose of this invention is to provide a self-cleaning control method for pickup truck air conditioners.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The self-cleaning control method for pickup truck air conditioning described in this invention employs an air conditioning system consisting of a compressor, controller, electronic expansion valve, four-way reversing valve, evaporator, condenser, and condenser fan, and includes the following steps:

[0007] S1, rapid cooling;

[0008] After entering the self-cleaning mode, the evaporator core temperature protection logic is disconnected, the compressor speed is controlled to increase to the first preset value, the condenser fan speed is increased accordingly, the electronic expansion valve opening remains unchanged, the blower speed in the evaporator is reduced by one level, the external circulation damper is closed, the internal circulation damper is opened, and rapid cooling is achieved.

[0009] S2, forms a frost layer;

[0010] The frost thickness of the evaporator core fins is acquired in real time, and the growth rate of the frost thickness is calculated. When the growth rate is greater than 0 and less than or equal to a first preset value, the compressor speed is controlled to decrease at a linear rate, the condenser fan speed is reduced accordingly, and the opening of the electronic expansion valve remains unchanged until the frost thickness meets the requirements, and then the operation is maintained for a certain period of time.

[0011] S3, defrost and dust removal;

[0012] Switch the direction of the four-way reversing valve and close the internal circulation damper and open the external circulation damper to introduce the high-temperature gas discharged from the compressor and the high-temperature air in the external environment into the evaporator core until the frost layer thickness of the evaporator core fins is 0. Then, control the blower in the evaporator to run at the lowest speed until the preset drainage time, and then switch the direction of the four-way reversing valve to enter the normal cooling mode.

[0013] Furthermore, 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.

[0014] Furthermore, 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.

[0015] Furthermore, the frost thickness sensor only starts working after the self-cleaning module is activated, in order to reduce the number of circuit ports used.

[0016] Furthermore, the frost layer thickness meets the following requirements: the frost layer thickness growth rate is 0 or the frost layer thickness reaches a preset thickness.

[0017] Furthermore, in step S1, if the evaporator core temperature protection logic is not disconnected, an alarm is triggered and execution is terminated until the alarm is cleared.

[0018] Furthermore, in step S3, once the frost layer thickness is detected to be 0, the drainage time begins immediately. The blower in the evaporator is reduced to its lowest speed to facilitate the rapid and effective dripping of condensate from the core surface under gravity, achieving efficient cleaning of the core surface and preventing the water in the water box from being unable to drain properly due to negative pressure caused by excessive blower speed.

[0019] The advantages of this invention are that it automatically cuts off the protection function of the original temperature sensor of the evaporator core when self-cleaning is initiated, preventing the activation of the vehicle air conditioner's own core protection logic and blocking the self-cleaning process. After self-cleaning is initiated, the degree of frost formation on the core is fed back through frost thickness monitoring and a set time. The compressor speed is controlled by the frost formation rate, effectively reducing the vehicle's energy consumption during self-cleaning and preventing damage to the core during repeated self-cleaning processes. During defrosting and dust removal, this invention adopts a bidirectional heating principle to achieve rapid melting of frost on the core, effectively reducing dust and particulate matter on the evaporator core and achieving the self-cleaning purpose of the vehicle air conditioner. Attached Figure Description

[0020] Figure 1 This is a diagram of a car's air conditioning system.

[0021] Figure 2 This is a schematic diagram of the airflow direction inside the driver's compartment of a car.

[0022] Figure 3 This is a flowchart of the method described in this invention. Detailed Implementation

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

[0024] like Figure 1 , Figure 2 The diagram shown illustrates the air conditioning system used in the self-cleaning control method for pickup truck air conditioning according to the present invention. 1 represents the air conditioning system compressor, 2 is a four-way reversing valve, 3 is a condenser fan, 4 is the condenser assembly, 5 is an electronic expansion valve, and 6 is the evaporator assembly. The evaporator assembly 6 consists of a blower 9 and an evaporator core 10. Figure 2 In the diagram showing the airflow direction inside the cab, 7 is the internal circulation damper, which opens only when the cab's internal circulation function is activated. 8 is the external circulation damper, which opens only when the external circulation function is activated. The internal circulation damper 7 and the external circulation damper 8 cannot be opened simultaneously. Figure 2 11 is a frost thickness sensor installed on the evaporator core 10.

[0025] Based on the above-mentioned air conditioning system, the self-cleaning control method for pickup truck air conditioning according to the present invention specifically includes the following steps:

[0026] S1, rapid cooling;

[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 controller on 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 compressor 1, condenser fan 3, and blower 9 to increase heat exchange and achieve rapid cooling. Specifically, the external circulation damper 8 is closed, the internal circulation damper 7 is opened, the compressor 1 frequency is increased to the first preset frequency, and the condenser fan 3 speed is increased to the first preset speed; the electronic expansion valve 5 remains unchanged; and the blower 9 operates at a reduced speed. These operations achieve rapid cooling and increase 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 monitored value among all the monitored values. The maximum monitored value can be the value of the point with the largest frost thickness among all monitored values, or the value of the point with the largest rate of increase of frost thickness among all monitored values.

[0031] The vehicle controller acquires the frost thickness in real time and calculates the rate of frost growth. When the frost growth rate exceeds a first preset value, the current operating state of the air conditioning system remains unchanged. When the frost growth rate is greater than 0 and less than or equal to the first preset value, the compressor 1 is controlled to reduce its frequency and the condenser fan 3 to reduce its speed until the frost thickness reaches the target and is maintained for a certain period of time. The determination that the frost thickness has reached the target can be based on the frost growth rate being 0 or the frost thickness on the surface of the evaporator core 10 reaching the preset thickness value.

[0032] Specifically, compressor 1 reduces its frequency to a second preset frequency at a first linear rate. Once compressor 1 reaches the second preset frequency, condenser fan 3 reduces its speed to a second preset speed to reduce vehicle energy consumption. The opening of electronic expansion valve 5 remains unchanged. Then, the air conditioning system operates under this condition until the frost thickness growth rate reaches zero or the frost thickness on the evaporator core 10 reaches a preset thickness. After this, compressor 1 maintains its current speed for a certain period of time, and condenser fan 3 and electronic expansion valve 5 also maintain their current operating states, allowing dust and dirt on the surface of the evaporator core 10 to adhere to the frost surface to the maximum extent.

[0033] It should be noted that the frost thickness sensor only starts working after the self-cleaning module is activated. At other times, the frost thickness sensor remains stationary 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 of the evaporator core 10 reaches the preset thickness and the compressor 1, condenser fan 3, and electronic expansion valve 5 maintain their current operation for a certain period of time, the rapid defrosting and dust removal self-cleaning step will begin. By switching the direction of the four-way reversing valve 2, the high-temperature gas discharged from the compressor 1 is directly introduced into the evaporator core 10. At the same time, the internal circulation damper 7 is closed and the external circulation damper 8 is opened to introduce high-temperature air from the outside environment onto the evaporator core 10. The defrosting process of the evaporator core 10 is accelerated through these two methods until the frost thickness on the surface of the evaporator core 10 is 0.

[0036] Once the frost layer thickness on the evaporator core 10 fins reaches zero, the drainage and dust removal process begins. At this time, the blower 9 in the evaporator is reduced to its lowest speed to facilitate the rapid and effective dripping of condensate from the frost layer on the surface of the evaporator core 10 under 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 6. This not only achieves efficient cleaning of the evaporator core 10 surface but also prevents water from flowing into the drain box and creating negative pressure due to excessive airflow from the blower 9, which would prevent the water in the drain box from draining properly. After maintaining this state for the preset drainage time, the four-way reversing valve 2 is switched to enter the normal cooling mode.

[0037] 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:

[0038] After the self-cleaning mode is activated, it checks whether the evaporator core temperature sensor signal is disconnected / shielded. If it is not disconnected / shielded, an alarm is triggered. After the alarm is cleared, it checks again whether the evaporator core temperature sensor signal is disconnected / shielded. If the evaporator core temperature sensor signal is disconnected, it enters the rapid cooling stage. The external circulation damper 8 is closed, the internal circulation damper 7 is opened, the compressor 1 frequency is increased to the first preset frequency, and the condenser fan 3 speed is increased to the first preset speed; the electronic expansion valve 5 remains open; and the blower 9 operates at a reduced speed.

[0039] 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.

[0040] When the rate of increase of the frost thickness is greater than 0 and less than or equal to the first preset value, the compressor 1 reduces its frequency to the second preset frequency at the first linear rate. After the compressor 1 reduces its frequency to the second preset frequency, the condenser fan 3 reduces its speed to the second preset speed. The opening of the electronic expansion valve 5 remains unchanged. The actual frost thickness of the evaporator core 10 is detected again in real time to determine the relationship between the frost thickness of the evaporator core 10 and the set rate.

[0041] When the frost thickness growth rate is 0 or the frost thickness of the evaporator core 10 reaches the preset thickness, the current state is maintained for a set time. Then, the four-way reversing valve 2 is switched, the internal circulation damper 7 is closed, and the external circulation damper 8 is opened. The frost thickness of the evaporator core 10 is detected in real time, and it is determined whether the frost 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, switch the four-way reversing valve 2 and simultaneously close the external circulation damper to 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, a four-way reversing valve, an evaporator, a condenser, and a condenser fan, characterized in that: Includes the following steps, S1, rapid cooling; After entering the self-cleaning mode, the evaporator core temperature protection logic is disconnected, the compressor speed is controlled to increase to the first preset value, the condenser fan speed is increased accordingly, the electronic expansion valve opening remains unchanged, the blower speed in the evaporator is reduced by one level, the external circulation damper is closed, the internal circulation damper is opened, and rapid cooling is achieved. 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 thickness of the evaporator core fins is acquired in real time, and the growth rate of the frost thickness is calculated. When the growth rate is greater than 0 and less than or equal to a first preset value, the compressor speed is controlled to decrease at a linear rate, the condenser fan speed is reduced accordingly, and the opening of the electronic expansion valve remains unchanged until the frost thickness meets the requirements, and then the operation is maintained for a certain period of time. Specifically: 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 compressor frequency is reduced and the condenser fan speed is reduced until the frost thickness reaches the standard and is maintained for a certain period of time. The frost thickness is determined to be at the standard when the frost thickness growth rate is 0 or the frost thickness on the surface of the evaporator core reaches the preset thickness value. The compressor reduces its frequency to a second preset frequency at a first linear rate. After the compressor reduces its frequency to the second preset frequency, the condenser fan reduces its speed to a second preset speed to reduce vehicle energy consumption. The opening of the electronic expansion valve remains unchanged. Then, the air conditioning system operates under this condition until the frost thickness growth rate is 0 or the frost thickness of the evaporator core reaches the preset thickness. The compressor then maintains its current speed for a certain period of time, and the condenser fan and electronic expansion valve also maintain their current operating state, so that dust and dirt on the surface of the evaporator core adhere to the frost surface to the maximum extent. S3, defrost and dust removal; Switch the direction of the four-way reversing valve and close the internal circulation damper and open the external circulation damper to introduce the high-temperature gas discharged from the compressor and the high-temperature air in the external environment into the evaporator core until the frost layer thickness of the evaporator core fins is 0. Then, control the blower in the evaporator to run at the lowest speed until the preset drainage time, and then switch the direction of the four-way reversing valve to enter the normal cooling mode.

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 layer thickness is detected to be 0, the drainage time begins immediately. The blower in the evaporator is reduced to its lowest speed to facilitate the rapid and effective dripping of condensate from the core surface under gravity, achieving efficient cleaning of the core surface and preventing the water in the water box from failing to drain properly due to negative pressure caused by excessive blower speed.

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