Control method for reducing fogging probability of automotive air conditioner and automobile

Abstract

The method comprises the steps that after an automatic air conditioner is started, whether a constant-temperature control condition is met or not is judged, if the constant-temperature control condition is met, whether the humidity in the automobile is lower than a set threshold value or not is judged, if yes, a compressor is allowed to be disconnected, and if not, the compressor is allowed to be disconnected. Otherwise, the compressor is forbidden to stop working. The method has the advantages that the fogging probability of the vehicle can be effectively reduced, and the method is suitable for low-configuration vehicle types or vehicle types developed at low cost.

Description

Technical Field

[0001] The invention relates to the field of automobile defrosting and defogger control, and in particular to a control method for reducing fogging probability of a vehicle air conditioner and a vehicle. Background Art

[0002] With the development of the times and industrial progress, people have higher and higher demands for living standards. As the main means of travel and transportation, passenger cars need to continuously improve their configurations and functions in terms of convenience, comfort and intelligence. For example, the automatic defog function was previously only available in Class B cars, but it is now gradually becoming popular as a standard feature. However, the hardware resources required for this configuration include humidity-sensitive chips, NTC thermistors, high-precision resistors, spectrum sensing circuits, etc.

[0003] If low-end models use stacked hardware configuration to achieve this automatic function, they not only need to add the same hardware configuration, but also need to complete the spring, autumn and winter automatic defogger road test condition calibration work. This poses a huge challenge to many projects with limited investment and short development cycle, and also requires the cost of increased quality risks, and may result in failure to achieve the established goals when the project was established;

[0004] The key condition for triggering the automatic defog function of passenger cars in the current industry is the judgment of the probability of fogging, and the calculation of the probability of fogging requires the dew point temperature of the front windshield, the glass temperature, the temperature inside the car, and the humidity inside the car to be included in the calculation. The algorithms used by some car companies also need to collect and include the intensity of sunlight. This series of variables needs to be implemented based on the sensor hardware acquisition circuit, which will also increase the cost. For low-end models, these costs are not acceptable, and the automatic defog function cannot be provided on low-end models, which cannot meet the needs of low-end or A0-class vehicles to avoid fogging. In addition, the automatic defog function currently commonly configured in the market will automatically trigger the air conditioner to turn on. Under some working conditions, when the owner concentrates on driving the vehicle, the sudden noise of the air conditioner blower and the feeling of blowing wind often cause discomfort to the driver, and there may be consequences of frightening and affecting driving. Summary of the invention

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

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a control method for reducing the probability of fogging of a vehicle air conditioner, including judging whether the constant temperature control conditions are met after the automatic air conditioner is turned on, and when the constant temperature control conditions are met, judging whether the humidity in the vehicle is lower than the set threshold value, if so, allowing the compressor to disconnect, otherwise prohibiting the compressor from disconnecting.

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

[0008] When the target air outlet temperature is higher than the actual air outlet temperature and the difference is greater than the set temperature threshold, it is determined that the constant temperature control condition is 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 condition is met.

[0010] Determine whether the humidity in the vehicle is lower than a set threshold. If the humidity in the vehicle is greater than the set threshold, control the compressor to keep running and maintain low speed or low displacement.

[0011] While controlling the compressor to maintain low speed or low displacement operation, adjust the air conditioning blending door towards the warm air direction to maintain constant temperature control in the vehicle.

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

[0013] The on-board humidity sensor in the car is used to obtain air humidity data. When the constant temperature control conditions are met, when the humidity is greater than the humidity threshold, the compressor is controlled to start and run continuously; the humidity threshold is 60% to 70%.

[0014] The control method is integrated in an air-conditioning controller and starts to work after the driver manually turns on the air-conditioning or the one-button defog function turns on the air-conditioning.

[0015] A car comprises the control method for reducing the fogging probability of a vehicle air conditioner.

[0016] The advantages of the present invention are that it can effectively reduce the probability of vehicle fogging, and is suitable for low-end models or models developed at low cost. It can solve the fogging problem of some low-end models, vehicles with low hardware configuration and relatively short development cycle, and models that cannot cover the regular spring, autumn and winter environments for road test calibration. The probability of fogging is greatly reduced through a software control method, thereby improving the user experience of the vehicle and improving reliability. It can achieve a low-cost solution to the fogging problem in the spring and autumn seasons existing in the prior art, and facilitate the development and use of low-end models and even A0-class vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0018] Figure 1 This is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0020] The main purpose of the patent of this invention is to solve the problem of some low-end models. The hardware configuration of the whole vehicle is not very high and the development cycle is relatively short. It is impossible to cover the models for road test calibration in the conventional spring, autumn and winter environments. However, there must be a feasible solution to reduce the risk of fogging of the front windshield during vehicle driving. The algorithm does not need to carry out a separate automatic defog condition calibration. All calibration work is carried out simultaneously with the 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 (calibration amount, 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 (calibration amount, generally between 1°C and 3°C), the prerequisite for turning off the compressor to achieve constant temperature control in the car is met, and the humidity parameter in the car is added as a supplementary judgment condition. After the improvement, if the evaporator target temperature is met but the humidity in the car is not met, the compressor is kept working at a low speed or controlled at a low displacement, and the mixing damper angle is adjusted to the heating direction to ensure constant temperature control in the car, so as to achieve effective control of the humidity in the car and reduce the risk of fogging of the windshield.

[0021] like Figure 1 As shown, a control method for reducing the probability of fogging of a vehicle air conditioner includes, after the automatic air conditioner is turned on, determining whether the constant temperature control conditions are met, and when the constant temperature control conditions are met, determining whether the humidity in the vehicle is lower than a set threshold, if so, allowing the compressor to disconnect, otherwise prohibiting the compressor from disconnecting.

[0022] The control method in this solution is integrated in the air-conditioning controller and starts working after the driver manually turns on the air-conditioning or the one-button defogger function turns on the air-conditioning, that is, the automatic air-conditioning starts only after the driver manually turns on the air-conditioning or turns on the air-conditioning through the one-button defogger function. If the air-conditioning is in the off state, the air-conditioning is turned on manually by the driver or the one-button defogger function, which is more in line with the human-computer interaction logic and avoids the perception of abrupt experience problems.

[0023] After the air conditioner is turned on, determine whether the constant temperature control conditions are met. Under normal circumstances, the compressor needs to be controlled to be turned off after the constant temperature control conditions are met. However, in order to reduce the probability of glass fogging, the humidity in the car needs to be judged after the constant temperature control conditions are met. Based on the humidity in the car, it is finally determined whether to control the compressor to continue running or allow the compressor to be disconnected.

[0024] In this solution, it is determined whether the constant temperature condition is met based on the air outlet temperature data or the evaporator temperature data. Specifically, when the target air outlet temperature is higher than the actual air outlet temperature and the difference is greater than the set temperature threshold, it is determined that the constant temperature control condition is met. Or 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 condition is met. The set temperature threshold can be calibrated and set according to actual conditions, such as the target air outlet temperature is 3°C higher than the actual air outlet temperature (calibration amount, generally between 3°C and 5°C) or the target evaporator temperature is 2°C higher than the actual evaporator temperature (calibration amount, generally between 1°C and 3°C). In this solution, when the target outlet temperature is 3°C higher than the actual 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 turned off to ensure constant temperature control. However, directly turning off the compressor will create the risk of glass fogging. Therefore, in the judgment of whether to turn off the compressor, the humidity condition is added. The operating state of the compressor is controlled by further judging whether the humidity condition is met after the constant temperature air conditioning condition is met.

[0025] Among them, it is judged whether the humidity in the car is lower than the set threshold. If the humidity in the car is greater than the set threshold, the compressor is controlled to keep running and keep running at a low speed or low displacement. The purpose of this is to maintain constant temperature and dehumidification to avoid glass fogging caused by excessive humidity. If the humidity is less than the set threshold, the compressor is allowed to disconnect and run. At this time, the compressor is adjusted and controlled to disconnect according to the actual working requirements of the air-conditioning controller; otherwise, the compressor is prohibited from disconnecting and running. At this time, the compressor needs to be kept running continuously, but in order to reduce the impact of the compressor and meet the purpose of dehumidification and reducing fogging, the operation of the compressor at this time is to control the compressor to keep running at a low speed or low displacement while adjusting the air-conditioning mixing damper to the warm air direction to maintain constant temperature control in the car, realize effective control of the humidity in the car, and reduce the risk of windshield fogging.

[0026] It is preferred to monitor the temperature inside the vehicle in real time while adjusting the mixing damper toward the warm air direction, and adjust the opening size of the mitigation damper according to the temperature fluctuation inside the vehicle. Because adjusting the mixing damper is to maintain constant temperature control in the vehicle, when the temperature fluctuates, the constant temperature control in the vehicle can be ensured by adjusting the size of the damper opening, thereby meeting the purpose of constant temperature control and reducing the risk of fogging.

[0027] For humidity data, the on-board humidity sensor in the car is used to obtain air humidity data. When the constant temperature control conditions are met, the compressor is controlled to start and run continuously when the humidity is greater than the humidity threshold; the humidity threshold is 60% to 70%. In the spring or autumn automatic air conditioning road test calibration process of low-configuration models, the following is adopted: the target air outlet temperature is 3°C higher than the actual air outlet temperature (calibration quantity, generally between 3°C and 5°C) mapping relationship. When the target evaporator temperature is 2°C higher than the actual evaporator temperature (calibration quantity, generally between 1°C and 3°C), the compressor needs to be shut down to ensure constant temperature control. The specific (calibration quantity, generally between 60% and 70%) parameter of whether the humidity HR in the car is lower than 65% is added as a supplementary judgment condition. If the evaporator target temperature is higher than the actual evaporator temperature and the humidity HR in the car is lower than the characteristic parameter, the compressor is allowed to be disconnected. Otherwise, the compressor is kept on at a low speed or a low displacement and the mixing damper is adjusted to the warm air direction to ensure constant temperature control in the car, so as to achieve effective control of the humidity in the car and reduce the risk of fogging of the windshield.

[0028] Since fogging usually occurs in spring, autumn, winter and other seasons, or even when the outside temperature is low, after the air conditioner is turned on, the outside temperature sensor collects the outside temperature data, and determines whether to start the control method in the above embodiment based on the outside temperature data. When the outside temperature is lower than the set threshold, the control method in this embodiment is started, otherwise it is not started.

[0029] The present solution also provides a car, which includes the control method for reducing the fogging probability of the vehicle air conditioner in the above embodiment. By integrating the control method in the car, the purpose of reducing the fogging risk of the windshield is achieved.

[0030] This solution can reduce the risk of fogging. The following is an introduction and analysis of the principle:

[0031] According to the mirror fogging principle, the basic factor of fogging is the temperature of the glass itself. The relative humidity and air temperature of the air that the glass surface contacts can be used to measure the mirror dew point temperature Tdp. In simple terms, if the air temperature Tx on the glass surface is greater than the dew point temperature Tdp, it will not fog. If the air temperature Tx on the glass surface is less than the dew point temperature Tdp, it will fog.

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

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

[0034] Since the car is equipped with a humidity sensor and a glass temperature sensor, the humidity HR and the glass temperature Tg can be directly collected. However, the air temperature Tx near the glass needs to be calculated and calibrated in combination with the interior temperature and the air conditioning status of the car.

[0035] After road tests and analysis, the detailed relationship between the fogging probability F and the dew point temperature Tdp, the air temperature near 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 relationship function. However, through a large number of calibration work, it is found that the most influential factor in this formula is humidity HR, that is, l im(F→HR), or this approximate principle applies in most spring and autumn environments with a temperature range of 5℃ to 25℃;

[0037] Therefore, in the spring or autumn automatic air-conditioning road test calibration process of lower-configuration models, the following is adopted: the target air outlet temperature is 3°C higher than the actual air outlet temperature (calibration amount, generally between 3°C and 5°C) mapping relationship; when the target evaporator temperature is 2°C higher than the actual evaporator temperature (calibration amount, generally between 1°C and 3°C), the compressor needs to be shut down to ensure constant temperature control. At the same time, the specific (calibration amount, generally between 60% and 70%) parameter of whether the humidity HR in the vehicle is lower than 65% is added as a supplementary judgment condition. If the evaporator target temperature is higher than the actual evaporator temperature and the humidity HR in the vehicle is lower than the characteristic parameter, the compressor is allowed to be disconnected. Otherwise, the compressor is kept on at a low speed or a low displacement and is turned on by adjusting the mixing damper towards the warm air direction to ensure constant temperature control in the vehicle, thereby effectively controlling the humidity in the vehicle and reducing the risk of windshield fogging.

[0038] In addition, compared with the automatic defogger of the traditional solution, the strategy described in this invention patent eliminates the active start-up of the air conditioner due to the risk of fogging, and there is no need to accurately calculate the fogging probability F, so the glass temperature sensor can be eliminated, allowing more vehicle models to be equipped with this strategy while also solving the problem of sudden changes in air volume caused by active startup.

[0039] The comparison table of vehicle hardware BOM of this solution with the existing technology is as follows:

[0040] It can be seen from the table that 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. It can reduce costs while reducing the probability of fogging. The control solution for reducing the probability of fogging can be achieved by reusing the components in the car, which greatly saves costs. At the same time, another purpose of the patent of this invention is to combine the current conventional automatic defogger function to automatically trigger the air conditioner to start up based on the high probability of fogging, so that the working sound of the air conditioner blower and the feeling of blowing suddenly appear from nothing, and the driver has no prediction. Optimization is proposed for this type of problem. After the air conditioner is turned on, the working time of the compressor is extended, and the humidity in the car is reduced, thereby reducing the risk of fogging; if the air conditioner is in the off state at this time, the driver still needs to manually turn on the air conditioner or start the air conditioner with the one-button defogger function. This is more in line with the human-computer interaction logic and avoids the perception of abrupt experience problems.

[0043] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A control method for reducing the probability of fogging of a vehicle air conditioner, characterized in that: This includes determining whether the constant temperature control conditions are met after the automatic air conditioner is turned on. When the constant temperature control conditions are met, determining whether the humidity in the vehicle is lower than a set threshold. If so, the compressor is allowed to disconnect, otherwise the compressor is prohibited from disconnecting.

2. A control method for reducing fogging probability of a vehicle air conditioner as claimed in claim 1, characterized in that: Whether the constant temperature condition is met is determined based on the air outlet temperature data or the evaporator temperature data.

3. A control method for reducing fogging probability of a vehicle air conditioner as claimed in claim 2, characterized in that: When the target air outlet temperature is higher than the actual air outlet temperature and the difference is greater than the set temperature threshold, it is determined that the constant temperature control condition is met.

4. A control method for reducing fogging probability of a vehicle air conditioner as claimed in claim 2, characterized in that: 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 condition is met.

5. A control method for reducing fogging probability of a vehicle air conditioner according to any one of claims 1 to 4, characterized in that: Determine whether the humidity in the vehicle is lower than a set threshold. If the humidity in the vehicle is greater than the set threshold, control the compressor to keep running and maintain low speed or low displacement.

6. A control method for reducing fogging probability of a vehicle air conditioner as claimed in claim 5, characterized in that: While controlling the compressor to maintain low speed or low displacement operation, adjust the air conditioning blending door towards the warm air direction to maintain constant temperature control in the vehicle.

7. A control method for reducing fogging probability of a vehicle air conditioner as claimed in claim 6, characterized in that: While adjusting the blending damper toward the warm air direction, the temperature inside the vehicle is monitored in real time, and the opening of the damper is adjusted according to the temperature fluctuations inside the vehicle.

8. A control method for reducing fogging probability of a vehicle air conditioner according to any one of claims 1 to 7, characterized in that: The on-board humidity sensor in the car is used to obtain air humidity data. When the constant temperature control conditions are met, when the humidity is greater than the humidity threshold, the compressor is controlled to start and run continuously; the humidity threshold is 60% to 70%.

9. A control method for reducing fogging probability of a vehicle air conditioner according to any one of claims 1 to 7, characterized in that: The control method is integrated in an air-conditioning controller and starts to work after the driver manually turns on the air-conditioning or the one-button defog function turns on the air-conditioning.

10. An automobile, characterized in that: The automobile includes a control method for reducing the fogging probability of a vehicle air conditioner as described in any one of claims 1-9.

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