Safe and energy-saving control method for air conditioner of electric vehicle

Abstract

The invention relates to the field of automobile intelligent control, in particular to a safe and energy-saving control method for an electric automobile air conditioner. According to the invention, a humiture sensor or an all-in-one sensor technology installed on a front windshield is employed. According to the environment temperature outside the vehicle, the temperature of the glass surface in the vehicle and the relative humidity of air in the vehicle, the fogging risk grade is determined; and the in-vehicle air conditioner control operation is executed based on the fogging risk level. The energy consumption of the air conditioning system can be optimized on the premise that the safe view is guaranteed, and refined and safe energy-saving management of the heat management control system can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of automobile intelligent control, and in particular to a safe and energy-saving control method for an air conditioner of an electric vehicle. Background Art

[0002] The cruising range of new energy vehicles, especially pure electric passenger vehicles, has always been the focus of customers, and even the primary factor in car purchase. The automobile air conditioning system is one of the three small electrics of electric vehicles, and the energy consumption of the air conditioning system ranks second to that of pure electric vehicles. Among them, the PTC heater and the electric compressor are the main energy-consuming parts of the air conditioning system. The heat source for heating the passenger compartment mainly comes from the PTC heater. The power to maintain the thermal comfort of the passenger compartment generally requires about 2 kilowatts, which consumes a lot of energy; the use of a heat pump system also requires 1 kilowatt. One of the ways to prevent fogging is to increase the proportion of external circulation fresh air, or even full external circulation fresh air, to avoid condensation and fogging or frosting on the relatively high temperature and humid air in the car and the relatively low temperature glass. It is particularly important to optimize the energy consumption of the air conditioning system while ensuring a safe field of view.

[0003] At present, there are some air conditioning circulation technologies and windshield temperature and humidity sensor technologies, but there is no way to combine the two to create a refined, safe and energy-saving thermal management control system. Summary of the invention

[0004] The present invention aims to solve the problem that when the passenger compartment of a new energy vehicle is heated at low temperature, a large proportion of the air conditioning external circulation air intake needs to be controlled to enter the air conditioning box in order to prevent the glass from fogging and frosting, and the heating energy consumption and heating performance of the passenger compartment are limited due to the high priority of preventing fogging and frosting. Provide a thermal management control system that prevents fogging and frosting with a minimum amount of fresh air from the external circulation, minimizes heating energy consumption, and improves heating performance, so as to achieve the best balance between visual safety, passenger comfort, and energy consumption. The specific technical solution is as follows: A safe and energy-saving control method for an electric vehicle air conditioner comprises a multi-in-one sensor arranged inside a front windshield and connected to a controller, wherein the multi-in-one sensor measures the windshield temperature (T-wg), the humidity inside the windshield, i.e., the humidity inside the vehicle (RH-in), and the temperature inside the windshield, i.e., the temperature inside the vehicle (T-in); the control method is performed according to the following steps: Step 1, based on the in-vehicle humidity (RH-in) and in-vehicle temperature (T-in), obtain the in-vehicle air dew point temperature (Td); Step 2, calculating the fogging temperature difference (ΔT) based on the windshield temperature (T-wg) and the dew point temperature of the air inside the vehicle (Td); Step 3: Confirm the fogging risk level, which is divided into five levels: L0, L1, L2, L3, and L4; Step 4: Adjust the air conditioning mode according to the fogging risk level.

[0005] Furthermore, in step 2, ΔT=T-wg-Td.

[0006] Further, step 3, the confirmation method is as follows: step 31: confirm the correction coefficient k based on the windshield temperature T-wg, and the correction coefficient value is: windshield temperature -20℃~-10℃, k is 0.5; -10℃~10℃, k is 0.3; 10℃~20℃, k is 0.6; step 32, calculate the fogging temperature difference threshold T=ΔT×k; step 33, confirm the fogging risk level according to the fogging temperature difference threshold T, and the confirmation range is: T>14℃ is L0 level, 14℃~12℃ is L1 level, 12℃~5℃ is L2 level, 5℃~3℃ is L3 level, T<3℃ is L4 level.

[0007] Furthermore, in step 4, the air conditioning mode is adjusted as follows: L0: No risk of fogging, the air conditioner does not change the existing operating status; L1 switches to external loop; L2 switches to external circulation and AC starts; L3 switches to external circulation, AC starts, foot blowing and window blowing; triggered when air outlet mode ≠ face blowing and air outlet target temperature - ambient temperature > -2℃; L4 switches to external circulation, AC starts, and windows are blown; it is triggered when the air outlet target temperature - ambient temperature > -2°C or the ambient temperature < 20°C.

[0008] Furthermore, it also includes step 5, fog risk level switching strategy: when the fog risk level changes from high to low, the risk level must change to low for at least 2 minutes before switching, and when the risk level changes from low to high, it is switched immediately.

[0009] The present invention uses a temperature and humidity sensor or an all-in-one sensor technology installed on the front windshield. According to the ambient temperature outside the vehicle, the temperature of the glass surface inside the vehicle, and the relative humidity of the air inside the vehicle, the fogging risk level is determined; and the air conditioning control operation inside the vehicle is performed based on the fogging risk level. The present invention can optimize the energy consumption of the air conditioning system while ensuring a safe field of view, and can achieve refined and safe energy-saving management of the thermal management control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the installation of the all-in-one sensor in the present invention. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] like Figure 1 As shown, the method of the present invention requires that an all-in-one sensor be arranged on the inner side of the front windshield and connected to a controller, and the all-in-one sensor measures the windshield temperature (T-wg), the humidity inside the windshield, i.e., the humidity inside the vehicle (RH-in), and the temperature inside the windshield, i.e., the temperature inside the vehicle (T-in).

[0013] The specific steps are as follows: Step 1, based on the in-vehicle humidity (RH-in) and in-vehicle temperature (T-in), obtain the in-vehicle air dew point temperature (Td); It can be directly obtained by querying the following table of ambient temperature, relative humidity and dew point comparison chart:

[0014] Step 2, calculating the fogging temperature difference (ΔT) based on the windshield temperature (T-wg) and the dew point temperature of the air inside the vehicle (Td); Step 3: Confirm the fogging risk level, which is divided into five levels: L0, L1, L2, L3, and L4; Step 4: Adjust the air conditioning mode according to the fogging risk level.

[0015] Furthermore, in step 2, ΔT=T-wg-Td.

[0016] Further, step 3, the confirmation method is as follows: step 31: confirm the correction coefficient k based on the windshield temperature T-wg, and the correction coefficient value is: windshield temperature -20℃~-10℃, k is 0.5; -10℃~10℃, k is 0.3; 10℃~20℃, k is 0.6; step 32, calculate the fogging temperature difference threshold T=ΔT×k; step 33, confirm the fogging risk level according to the fogging temperature difference threshold T, and the confirmation range is: T>14℃ is L0 level, 14℃~12℃ is L1 level, 12℃~5℃ is L2 level, 5℃~3℃ is L3 level, T<3℃ is L4 level.

[0017] Furthermore, in step 4, the air conditioning mode is adjusted as follows: L0: No risk of fogging, the air conditioner does not change the existing operating status; L1 switches to external loop; L2 switches to external circulation and AC starts; L3 switches to external circulation, AC starts, foot blowing and window blowing; triggered when air outlet mode ≠ face blowing and air outlet target temperature - ambient temperature > -2℃; L4 switches to external circulation, AC starts, and windows are blown; it is triggered when the air outlet target temperature - ambient temperature > -2°C or the ambient temperature < 20°C.

[0018] Furthermore, it also includes step 5, fog risk level switching strategy: when the fog risk level changes from high to low, the risk level must change to low for at least 2 minutes before switching, and when the risk level changes from low to high, it is switched immediately.

[0019] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A safe and energy-saving control method for electric vehicle air conditioning, characterized in that: An all-in-one sensor is arranged inside the front windshield and connected to the controller. The all-in-one sensor measures the windshield temperature T-wg, the humidity inside the windshield, i.e., the humidity inside the vehicle RH-in, and the temperature inside the windshield, i.e., the temperature inside the vehicle T-in. The control method is performed according to the following steps: Step 1, based on the in-vehicle humidity RH-in and the in-vehicle temperature T-in, obtain the in-vehicle air dew point temperature Td; Step 2, calculating the fogging temperature difference ΔT based on the windshield temperature T-wg and the dew point temperature Td of the air inside the vehicle; Step 3: Confirm the fogging risk level, which is divided into five levels: L0, L1, L2, L3, and L4; Step 4: Adjust the air conditioning mode according to the fogging risk level.

2. The electric vehicle air conditioner safety and energy-saving control method according to claim 1, characterized in that: In step 2, ΔT=T-wg - Td.

3. The electric vehicle air conditioner safety and energy-saving control method according to claim 1 is characterized in that: Step 3, the confirmation method is as follows: Step 31: confirm the correction coefficient k based on the windshield temperature T-wg, and the value of the correction coefficient is: windshield temperature -20℃~-10℃, k is 0.5; -10℃~10℃, k is 0.3; 10℃~20℃, k is 0.6; Step 32, calculate the fogging temperature difference threshold T=ΔT×k; Step 33, confirm the fogging risk level according to the fogging temperature difference threshold T, and the confirmation range is: T>14℃ is L0 level, 14℃~12℃ is L1 level, 12℃~5℃ is L2 level, 5℃~3℃ is L3 level, T<3℃ is L4 level.

4. The electric vehicle air conditioner safety and energy-saving control method according to claim 1, characterized in that: In step 4, the air conditioning mode is adjusted as follows: L0: No risk of fogging, the air conditioner does not change the existing operating status; L1 switches to external loop; L2 switches to external circulation and AC starts; L3 switches to external circulation, AC starts, foot and window blowing; Triggered when air outlet mode ≠ blowing on the face and air outlet target temperature - ambient temperature > -2°C; L4 switches to external circulation, AC starts, and windows are blown; it is triggered when the air outlet target temperature - ambient temperature > -2°C or the ambient temperature < 20°C.

5. The electric vehicle air conditioner safety and energy-saving control method according to claim 1 is characterized in that: It also includes step 5, fog risk level switching strategy: when the fog risk level changes from high to low, the risk level must change to low for at least 2 minutes before switching, and when the risk level changes from low to high, it switches immediately.

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