A control method for reducing the fogging probability of a vehicle air conditioner and a vehicle

Abstract

This invention discloses a control method and a vehicle for reducing the probability of fogging in automotive air conditioning. The method includes, after the automatic air conditioning is turned on, determining whether a constant temperature control condition is met. If the constant temperature control condition is met, determining whether the humidity inside the vehicle is below a set threshold. If so, the compressor is allowed to shut off; otherwise, the compressor is prohibited from shutting off. The advantage of this invention is that it can effectively reduce the probability of fogging in vehicles and is suitable for low-end models or low-cost developed models.

Description

Technical Field

[0001] This invention relates to the field of automotive defrosting and defogging control, and particularly to a control method for reducing the probability of fogging in automotive air conditioning and an automotive vehicle. Background Technology

[0002] With the development of the times and the progress of industry, people have higher and higher demands for living standards. As the main means of travel and transportation, passenger cars need to be continuously improved in terms of convenience, comfort and intelligence. For example, the automatic defogging function, which was previously only available in B-class cars, is now gradually becoming a standard feature. However, the hardware resources required for this feature, such as humidity-sensitive chips, NTC thermistor high-precision resistors and spectral sensing circuits, are indispensable.

[0003] If the low-end model adopts the stacked hardware configuration to achieve this automatic function, it will not only require the same hardware configuration, but also need to complete the calibration of automatic defogging road test conditions in spring, autumn and winter. This poses a huge challenge to many projects with limited investment and short development cycles. It also requires paying the price of increased quality risk, and there may be a result that the established goals at the time of project initiation cannot be achieved.

[0004] Currently, the key trigger condition for automatic defogging functions in passenger vehicles is the determination of the probability of fogging. This probability calculation requires the inclusion of factors such as the windshield dew point temperature, glass temperature, interior temperature, and interior humidity. Some automakers also use algorithms that incorporate sunlight intensity. All these variables require sensor hardware acquisition circuitry, increasing costs. For lower-spec models, these costs are unacceptable, preventing the provision of automatic defogging functions and failing to meet the fogging avoidance needs of low-spec or A0-class vehicles. Furthermore, the commonly available automatic defogging function automatically triggers the air conditioning to turn on. Under certain conditions, when drivers are focused on driving, the sudden noise and blowing of the air conditioning blower can cause discomfort and potentially lead to startling and impaired driving. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a control method and automobile for reducing the probability of fogging in automotive air conditioning, which can effectively reduce the probability of vehicle fogging and is suitable for low-end models or low-cost models.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a control method for reducing the probability of fogging in a vehicle air conditioner, comprising determining whether a constant temperature control condition is met after the automatic air conditioner is turned on; if the constant temperature control condition is met, determining whether the humidity inside the vehicle is lower than a set threshold; if so, allowing the compressor to disconnect from operation; otherwise, prohibiting the compressor from disconnecting from operation.

[0007] Determine whether the constant temperature condition is met based on the air outlet temperature data or the evaporator temperature data.

[0008] If the target air outlet temperature is higher than the actual air outlet temperature and the difference is greater than the set temperature threshold, then the constant temperature control conditions are met.

[0009] When the target evaporator temperature is higher than the actual evaporator temperature and the difference is greater than the set temperature threshold, it is determined that the constant temperature control conditions are met.

[0010] The system determines whether the humidity inside the vehicle is below a set threshold. If the humidity inside the vehicle is above the set threshold, it controls the compressor to keep running and maintains low speed or low displacement.

[0011] While controlling the compressor to operate at low speed or low displacement, the air conditioning mixing damper is adjusted to direct warm air to maintain constant temperature control inside the vehicle.

[0012] While adjusting the mixing damper towards the warm air direction, the vehicle interior temperature is monitored in real time, and the opening of the damper is adjusted according to the temperature fluctuations inside the vehicle.

[0013] The system uses an in-vehicle humidity sensor to acquire air humidity data. When the constant temperature control conditions are met, the system controls the compressor to start and run continuously when the humidity exceeds a humidity threshold of 60% to 70%.

[0014] The control method is integrated into the air conditioning controller and starts working after the driver manually turns on the air conditioning or turns on the air conditioning with the one-button defogging function.

[0015] An automobile, the automobile including the aforementioned control method for reducing the probability of fogging in an automotive air conditioner.

[0016] The advantages of this invention are: it effectively reduces the probability of vehicle fogging, making it suitable for low-spec models or low-cost developed models. It solves the fogging problem in some low-spec models, vehicles with relatively low hardware configurations and short development cycles, and for models that cannot be calibrated through road tests in typical spring, autumn, and winter environments. Through software control methods, the probability of fogging is significantly reduced, thereby improving the user experience and reliability. It provides a low-cost solution to the fogging problem in spring and autumn, facilitating the development and use of low-spec models and even A0-class vehicles. Attached Figure Description

[0017] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0018] Figure 1 This is a flowchart of the control method of the present invention. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0020] The main purpose of this invention is to address the issue of low-spec vehicles with relatively low hardware configurations and short development cycles that cannot be calibrated under typical spring, autumn, and winter conditions. However, it also aims to provide a feasible solution to reduce the risk of windshield fogging during vehicle operation. This algorithm eliminates the need for separate automatic defogging calibration; all calibration is conducted concurrently with automatic air conditioning comfort road test calibration. In spring and autumn, the target air outlet temperature is 3°C higher than the actual air outlet temperature (calibrated value, generally between 3°C and 5°C). The mapping relationship is: when the target evaporator temperature is 2°C higher than the actual evaporator temperature (calibrated value, generally between 1°C and 3°C), the compressor can be shut off to achieve constant temperature control inside the vehicle. In addition, in-vehicle humidity is added as a supplementary criterion. After the improvement, if the target evaporator temperature is met but the in-vehicle humidity is not, the compressor continues to operate at low speed or with low displacement. The mixing damper angle is adjusted towards the heating direction to ensure constant temperature control inside the vehicle, effectively controlling in-vehicle humidity and reducing the risk of windshield fogging.

[0021] like Figure 1 As shown, a control method for reducing the probability of fogging in a vehicle air conditioner includes determining whether a constant temperature control condition is met after the automatic air conditioner is turned on. If the constant temperature control condition is met, determining whether the humidity inside the vehicle is lower than a set threshold. If so, the compressor is allowed to shut off; otherwise, the compressor is prohibited from shutting off.

[0022] The control method in this solution is integrated into the air conditioning controller and begins to operate after the driver manually turns on the air conditioning or activates it via the one-button defogging function. In other words, the automatic air conditioning activation only begins after the driver manually turns on the air conditioning or activates it via the one-button defogging function. If the air conditioning is off, it is activated manually by the driver or passengers via the one-button defogging function, which better aligns with human-computer interaction logic and avoids perceptible abrupt user experience issues.

[0023] After the air conditioner is turned on, it is necessary to determine whether the constant temperature control conditions are met. Under normal circumstances, the compressor should be shut down after the constant temperature control conditions are met. However, in order to reduce the probability of fogging of the glass, the humidity inside the vehicle should also be judged after the constant temperature control conditions are met. The final decision is made based on the humidity inside the vehicle to determine whether to control the compressor to continue running or allow the compressor to be shut off.

[0024] In this solution, the temperature control condition is determined based on either the outlet air temperature or the evaporator temperature data. Specifically, if the target outlet air temperature is higher than the actual outlet air temperature and the difference is greater than the set temperature threshold, the temperature control condition is considered met. Alternatively, if the target evaporator temperature is higher than the actual evaporator temperature and the difference is greater than the set temperature threshold, the temperature control condition is considered met. The set temperature threshold can be calibrated according to actual conditions, such as a target outlet air temperature 3℃ higher than the actual outlet air temperature (calibration value, generally between 3℃ and 5℃) or a target evaporator temperature 2℃ higher than the actual evaporator temperature (calibration value, generally between 1℃ and 3℃). In this scheme, the target air outlet temperature is 3℃ higher than the actual air outlet temperature (standard value, generally between 3℃ and 5℃). When the target evaporator temperature is 2℃ higher than the actual evaporator temperature (standard value, generally between 1℃ and 3℃), the compressor needs to be shut down to ensure constant temperature control. However, directly shutting down the compressor will cause the glass to fog up. Therefore, humidity conditions are added to the judgment of whether to shut down the compressor. After the constant temperature air conditioning conditions are met, the humidity conditions are further judged to control the operation of the compressor.

[0025] The system determines whether the humidity inside the vehicle is below a set threshold. If the humidity is above the threshold, the compressor continues to run at a low speed or low displacement to maintain a constant temperature and dehumidify, preventing fogging of the windshield due to excessive humidity. If the humidity is below the threshold, the compressor is allowed to shut off, with the compressor's shutdown adjusted according to the actual operating needs of the air conditioning controller. Otherwise, the compressor is prohibited from shutting off and must continue running. However, to minimize the compressor's impact while still achieving the goal of dehumidification and reducing fogging, the compressor operates at a low speed or low displacement while the air conditioning's mixing damper directs air towards warmer air to maintain a constant temperature inside the vehicle, effectively controlling humidity and reducing the risk of windshield fogging.

[0026] The preferred method is to monitor the interior temperature in real time while adjusting the mixing damper to direct warm air. The opening of the damper is adjusted according to the temperature fluctuations inside the vehicle. This is because adjusting the mixing damper is to maintain a constant temperature inside the vehicle. When the temperature fluctuates, the opening of the damper can be adjusted to ensure a constant temperature inside the vehicle, thereby achieving the goal of constant temperature control and reducing the risk of fogging.

[0027] For humidity data, an in-vehicle humidity sensor is used to acquire air humidity data. When the humidity exceeds a certain threshold (60%–70%), and the constant temperature control conditions are met, the compressor is started and runs continuously. During the spring or autumn road test calibration of the automatic air conditioning in lower-configuration models, the following mapping is used: when the target air outlet temperature is 3°C higher than the actual air outlet temperature (calibrated value, generally between 3°C and 5°C), and the target evaporator temperature is 2°C higher than the actual evaporator temperature (calibrated value, generally between 1°C and 3°C), the compressor needs to be shut off to ensure constant temperature control. At the same time, a specific parameter (calibrated value, generally between 60% and 70% of the vehicle's humidity HR) is added as a supplementary judgment condition: if the target evaporator temperature is higher than the actual evaporator temperature and the vehicle's humidity HR is lower than the characteristic parameter, the compressor is allowed to be disconnected. Otherwise, the compressor continues to run at a low speed or a low displacement, and the mixing damper is adjusted to direct the warm air to ensure constant temperature control inside the vehicle, thereby achieving effective control of the humidity inside the vehicle and reducing the risk of windshield fogging.

[0028] Since fogging typically occurs in spring, autumn, and winter, and even when the outside temperature is low, the system uses an outside temperature sensor to collect outside temperature data after the air conditioning is turned on. Based on this data, it determines whether to activate the control method described in the above embodiment. If the outside temperature is below a set threshold, the control method is activated; otherwise, it is not.

[0029] This solution also provides a car that includes the control method for reducing the probability of fogging of the vehicle air conditioner in the above embodiments. By integrating the control method into the car, the purpose of reducing the risk of windshield fogging can be achieved.

[0030] This solution can reduce the risk of fogging. The principle and analysis are explained below:

[0031] Based on the principle of mirror fogging, the fundamental factor causing fogging is the temperature of the glass itself. Fogging is measured by the relative humidity and temperature of the air in contact with the glass surface. The dew point temperature (Tdp) of the mirror can be calculated from the relative humidity and the glass temperature. Simply put, if the air temperature (Tx) on the glass surface is greater than the dew point temperature (Tdp), fogging will not occur; if the air temperature (Tx) on the glass surface is less than the dew point temperature (Tdp), fogging will occur.

[0032] The probability F of fog formation can be obtained as: F = g(Tdp, Tx), where g represents the relationship function between the probability and Tdp and Tx.

[0033] The relationship between dew point temperature Tdp is: Tdp = f1(Tg, HR), where f1 represents the relationship function between Tg, HR and dew point temperature.

[0034] Because the vehicle is equipped with humidity and glass temperature sensors, humidity (HR) and glass temperature (Tg) can be directly collected. However, the air temperature (Tx) near the glass needs to be calculated and calibrated in conjunction with the interior temperature and the status of the air conditioning.

[0035] Based on road tests and analysis, the detailed relationships between the fogging probability F and the dew point temperature Tdp, the air temperature around the glass Tx, the glass temperature Tg, the air humidity HR, and the interior temperature Ti can be obtained as follows:

[0036] F = g(Tdp, Tx) = g(Tdp, f2(Tg, Ti)) = g(f1(Tg, HR), f2(Tg, Ti)), where f2 is the relational function. However, through extensive calibration work, it has been found that the most influential factor in this formula is humidity (HR), i.e., lim(F→HR), or this approximate principle applies to most spring and autumn environments with temperatures ranging from 5°C to 25°C.

[0037] Therefore, during the spring or autumn road test calibration of automatic air conditioning in lower-configuration models, the following mapping relationship is adopted: when the target air outlet temperature is 3℃ higher than the actual air outlet temperature (calibrated value, generally between 3℃ and 5℃), and the target evaporator temperature is 2℃ higher than the actual evaporator temperature (calibrated value, generally between 1℃ and 3℃), the compressor needs to be shut off to ensure constant temperature control. At the same time, a specific parameter (calibrated value, generally between 60% and 70%) of whether the vehicle interior humidity (HR) is lower than 65% is added as a supplementary judgment condition. If the target evaporator temperature is higher than the actual evaporator temperature and the vehicle interior humidity (HR) is lower than the characteristic parameter, the compressor is allowed to be disconnected. Otherwise, the compressor continues to run at a low speed or a low displacement and the mixing damper is adjusted to the direction of warm air to ensure constant temperature control inside the vehicle, thereby achieving effective control of vehicle interior humidity and reducing the risk of windshield fogging.

[0038] In addition, the strategy described in this invention patent eliminates the need for the air conditioner to be turned on automatically due to the risk of fogging, compared to the traditional solution. It also eliminates the need to accurately calculate the fogging probability F, thus eliminating the need for a glass temperature sensor. This allows more models to adopt this strategy while also solving the problem of sudden changes in airflow caused by active start-up.

[0039] The following is a comparison table of the vehicle hardware BOM of this solution compared to existing technologies:

[0040] As can be seen from the table, this solution can save at least one glass temperature sensor, thereby saving vehicle development costs.

[0041]

[0042] This solution is suitable for low-cost vehicle development, reducing costs while simultaneously decreasing the probability of fogging. The fogging reduction control scheme can be implemented using in-vehicle components, significantly saving costs. Another objective of this invention is to address the issue that current conventional automatic defogging functions automatically trigger the air conditioning to start based on a high fogging probability. This results in a sudden increase in air conditioning fan noise and airflow without driver warning. The proposed optimization extends the compressor's operating time after the air conditioning is turned on, reducing interior humidity and thus lowering the risk of fogging. If the air conditioning is off, passengers still need to manually turn it on or activate it using the one-button defogging function, which aligns better with human-machine interaction logic and avoids noticeable abrupt user experience issues.

[0043] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A control method for reducing the probability of fogging in automotive air conditioning, characterized in that: This includes determining whether constant temperature control conditions are met after the automatic air conditioning is turned on; if so, determining whether the humidity inside the vehicle is below a set threshold; if so, allowing the compressor to shut off; otherwise, prohibiting the compressor from shutting off; determining whether constant temperature conditions are met based on vent temperature data or evaporator temperature data; determining whether constant temperature control conditions are met when the target vent temperature is higher than the actual vent temperature and the difference is greater than the set temperature threshold; or determining whether constant temperature control conditions are met when the target evaporator temperature is higher than the actual evaporator temperature and the difference is greater than the set temperature threshold; and determining whether the humidity inside the vehicle is below a set threshold. If the humidity inside the vehicle is above the set threshold, controlling the compressor to continue running at a low speed or low displacement.

2. The control method for reducing the probability of fogging in a vehicle air conditioner as described in claim 1, characterized in that: While controlling the compressor to operate at low speed or low displacement, the air conditioning mixing damper is adjusted to direct warm air to maintain constant temperature control inside the vehicle.

3. The control method for reducing the probability of fogging in a vehicle air conditioner as described in claim 2, characterized in that: While adjusting the mixing damper towards the warm air direction, the vehicle interior temperature is monitored in real time, and the opening of the damper is adjusted according to the temperature fluctuations inside the vehicle.

4. A control method for reducing the probability of fogging in a vehicle air conditioner as described in any one of claims 1-3, characterized in that: The system uses an in-vehicle humidity sensor to acquire air humidity data. When the constant temperature control conditions are met, the system controls the compressor to start and run continuously when the humidity exceeds a humidity threshold of 60% to 70%.

5. A control method for reducing the probability of fogging in a vehicle air conditioner as described in any one of claims 1-3, characterized in that: The control method is integrated into the air conditioning controller and starts working after the driver manually turns on the air conditioning or turns on the air conditioning with the one-button defogging function.

6. A car, characterized in that: The vehicle includes the control method for reducing the probability of fogging in the vehicle air conditioner as described in any one of claims 1-5.

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