Thermal management control system and method for fan, water pump and air blower of pure electric vehicle

Abstract

The invention relates to the technical field of thermal management of pure electric vehicles, in particular to a thermal management control system and method for a fan, a water pump and an air blower of a pure electric vehicle, and a fan, an air blower and a water pump are arranged in the thermal management control system. The optimal energy consumption ratio (COP) is taken as a target, compared with a traditional heat management system, only corresponding assemblies are independently controlled, the requirement for a controller and data collection are reduced, and a control mode is optimized; specifically, input control is conducted according to the environment temperature and the rotating speed of a compressor, a cooperative control method is adopted, all low-pressure assemblies are combined, the optimal energy consumption ratio of each low-pressure assembly is found out, and then cooperative control is conducted. Compared with a traditional control method, the overall structure is simplified, and the overall optimal energy consumption ratio is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management of pure electric vehicles, and in particular to a thermal management control system and method for a fan, water pump and blower of a pure electric vehicle. Background Art

[0002] At present, the energy consumption of the thermal control system of pure electric vehicles under cooling conditions accounts for 9.8% to 26.9% of the total vehicle energy consumption. The thermal management systems commonly used on the market usually only regulate high-voltage components such as compressors and solenoid valves, and lack control over low-voltage components such as fans, blowers and water pumps, resulting in high system energy consumption and low energy efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a thermal management control system and method for a fan, water pump and blower of a pure electric vehicle, aiming to solve the problems of system efficiency and high energy consumption caused by unreasonable control of low-voltage parts in existing pure electric vehicles.

[0004] To achieve the above-mentioned objectives, the present invention provides a thermal management control system for a fan, water pump and blower of a pure electric vehicle, comprising a refrigeration system module, a battery pack module, a motor electronic control heat dissipation module and a cab module. The battery pack module and the cab module are connected in parallel to the refrigeration system module. The cab achieves the purpose of cooling by heat exchange of the refrigerant through the compressor and evaporator components. The motor circuit and the battery pack circuit are heat exchanged by the coolant flowing through the outdoor radiator and the heat exchanger. The fan, blower and water pump are all included in the refrigeration system module.

[0005] Among them, the fan is the fan of the outdoor radiator and condenser. When the high-temperature and high-pressure gaseous refrigerant flows out through the compressor and enters the outdoor radiator and condenser, in order to quickly cool it to liquid state, the fan needs to be turned on to exchange heat between the refrigerant and the external environment.

[0006] The blower is driven by a motor to inhale and push the air flow through the blades. The air inside the cabin is sucked in and pushed to the evaporator of the HVAC system through the rotation of the fan blades. Here, the refrigerant is compressed by a thermal expansion valve and converted into a low-temperature gaseous refrigerant, which is used to cool the air transmitted by the blower and then blown into the cabin to complete the refrigeration cycle.

[0007] Among them, two water pumps are provided in the thermal management control system, one is a water pump for controlling the circulating cooling water circuit of the battery pack, and the other is a water pump for controlling the cooling water circuit of the motor and controller.

[0008] Furthermore, the present invention also proposes a thermal management control method for a pure electric vehicle fan water pump blower, using the thermal management control system of the pure electric vehicle fan water pump blower, comprising the following steps:

[0009] Step 1: Collect the current ambient temperature T and compressor speed x R ;

[0010] Step 2: Calculate the optimal energy efficiency ratio of the fan, battery pack circulating cooling water circuit control pump and blower under the current working conditions respectively;

[0011] Step 3: Collaborative control outputs the optimal fan speed y fan , optimal pump speed y pump , optimal blower air volume y Hvac .

[0012] Optionally, the calculation formula for the fan speed with the optimal energy efficiency ratio in step 2 is as follows:

[0013]

[0014] Where y Fan is the condensing wind speed of the fan; x R is the compressor speed.

[0015] Optionally, the calculation formula for the speed of the blower with the optimal energy efficiency ratio in step 2 is as follows:

[0016] COP Hvac =0.0047y Hvac -0.0005x R +2.9604

[0017] Where y Hvac is the HVAC air volume; x R is the compressor speed.

[0018] Optionally, the calculation formula for the speed of the water pump with the optimal energy efficiency ratio in step 2 is as follows:

[0019]

[0020] Where y Pump is the coolant flow rate; x R is the compressor speed.

[0021] The present invention provides a thermal management control system and method for a fan, water pump and blower of a pure electric vehicle, wherein a fan, a blower and a water pump are provided in the thermal management control system. With the best energy consumption ratio (COP) as the goal, compared with the traditional thermal management system, only the corresponding components are controlled separately, the demand for the controller and the collection of data are reduced, and the control mode is optimized; input control is performed specifically according to the ambient temperature and the speed of the compressor, and a control method of coordinated control is adopted to combine various low-voltage components, first find out their respective best energy consumption ratios, and then perform coordinated control. Compared with the traditional control method, the overall structure is simplified, and the overall best energy consumption ratio is also greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of a specific implementation architecture of a thermal management control system of a fan water pump blower of a pure electric vehicle of the present invention.

[0024] Figure 2 It is a control strategy flow chart of a thermal management control system and method for a fan water pump blower of a pure electric vehicle according to the present invention.

[0025] Figure 3 Schematic diagram of COP at different compressor speeds under different HVAC air volumes, condensing air speeds and coolant flow rates in a specific embodiment of the present invention when the ambient temperature is 38°C.

[0026] Figure 4 Schematic diagram of COP at different compressor speeds under different HVAC air volumes, condensing air speeds and coolant flow rates in a specific embodiment of the present invention at an ambient temperature of 42°C.

[0027] Figure 5 It is a schematic diagram of the functional relationship between the HVAC air volume, condensing wind speed, coolant flow rate, compressor speed, and COP after fitting in a specific embodiment of the present invention.

[0028] Figure 6 It is a comparison diagram of the refrigeration capacity and the condenser outlet pressure at different compressor speeds under the ambient temperature of 38° C. in the specific embodiment of the present invention and the method of the present invention.

[0029] Figure 7 38° C. ambient temperature, the COP comparison diagram of the system under different compressor speeds in the conventional control method and the method of the present invention in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] The present invention provides a thermal management control system for a fan, water pump and blower of a pure electric vehicle, including a refrigeration system module, a battery pack module, a motor electronic control heat dissipation module and a cab module. The battery pack module and the cab module are connected in parallel to the refrigeration system module. The cab mainly achieves the purpose of cooling by exchanging heat with the refrigerant through components such as a compressor and an evaporator. The motor circuit and the battery pack circuit are cooled by the coolant flowing through an outdoor radiator and a heat exchanger to exchange heat, thereby achieving the purpose of cooling the motor and the battery pack. The fan, blower and water pump are all included in the refrigeration system module. Figure 1 Shown is a schematic diagram of a specific implementation architecture of a thermal management control system for a fan water pump blower of a pure electric vehicle according to the present invention.

[0032] Furthermore, the present invention also proposes a thermal management control method for a pure electric vehicle fan water pump blower, using the thermal management control system of the pure electric vehicle fan water pump blower, comprising the following steps:

[0033] Step 1: Collect the current ambient temperature T and compressor speed x R ;

[0034] Step 2: Calculate the optimal energy efficiency ratio of the fan, battery pack circulating cooling water circuit control pump and blower under the current working conditions respectively;

[0035] Step 3: Collaborative control outputs the optimal fan speed y fan , optimal pump speed y pump , optimal blower air volume y Hvac .

[0036] Specifically, the working process of the method for controlling the fan, water pump and blower of the thermal management system of a pure electric vehicle according to the present invention is as follows: Figure 2 As shown, the input end collects the current ambient temperature T and compressor speed x R , through the three set algorithm formulas, the wind speed, air volume and flow corresponding to the optimal energy efficiency ratio (COP) value under the current working conditions are calculated as input to control the operation of fans, blowers and water pumps.

[0037] The following is a further explanation based on the system architecture and implementation steps:

[0038] The COP of a refrigeration system is an important indicator for measuring the energy efficiency of a refrigeration system, that is, the cooling capacity obtained per unit energy consumption of the system. Therefore, the COP calculation formula is as follows:

[0039]

[0040] In the formula, Q evap , Q chiller Respectively represent the cooling capacity of the evaporator and chiller; W comp , Wfan , W blower and W pump Represents the energy consumption (Kw) of the compressor, fan, blower and water pump respectively.

[0041] The fan in the present invention is a fan for an outdoor radiator and a condenser, and a dry-bulb thermometer and an anemometer are provided in the assembly. When the high-temperature and high-pressure gaseous refrigerant flows out through the compressor and enters the outdoor radiator and the condenser, in order to quickly cool it down to a liquid state, the fan needs to be turned on to exchange heat between the refrigerant and the external environment. When the temperature monitored by the dry-bulb thermometer reaches a certain height, it is fed back to the fan through the temperature sensor, and the fan is turned on. The airflow is generated by rotation, and the external air is sucked in and blown across the surface of the radiator and the condenser to achieve the purpose of cooling the refrigerant and liquefying it into a liquid. When the target temperature drops to a set range, or the wind speed is too high, the temperature sensor and the wind speed sensor will work together on the fan to adjust its wind speed. In order to make the working condition of the fan meet the optimal energy efficiency ratio (COP), the present invention adopts a more suitable control method. By inputting the ambient temperature and the compressor speed, the speed of the fan with the optimal energy efficiency ratio under the working conditions is calculated, and then the optimal fan wind speed is output. The specific algorithm is shown in the following formula:

[0042]

[0043] Where y Fan is the condensing wind speed of the fan; x R is the compressor speed.

[0044] The blower is an important component in the automotive HVAC (heating, ventilation and air conditioning). The blower is driven by a motor to suck in and push the air flow. The air inside the cabin is sucked in and pushed to the evaporator of the HVAC system through the rotation of the fan blades. Here, the refrigerant is compressed by the thermal expansion valve and becomes a low-temperature liquid refrigerant, which is used to cool the air transmitted by the blower and then blown into the cabin to complete the refrigeration cycle. In high humidity conditions, the blower can help remove moisture from the air, reduce humidity, and thus increase comfort. The wind speed of the blower is usually adjusted by changing the voltage or using a variable speed controller to control the air flow. In order to make the working condition of the blower meet the optimal energy efficiency ratio (COP), the present invention adopts a more suitable control method. By inputting the ambient temperature and the compressor speed, the wind speed of the blower with the optimal energy efficiency ratio under the working conditions is calculated, and then the optimal blower air volume is output. The specific algorithm is shown in the following formula:

[0045] COP Hvac =0.0047y Hvac -0.0005x R +2.9604

[0046] Where y Hvac is the HVAC air volume; xR is the compressor speed.

[0047] There are two water pumps in this thermal management system, one is the battery pack circulating cooling water circuit control water pump, and the other is the motor and controller cooling water circuit control water pump. The two circuits are connected in series and parallel by a four-way valve, and the connection with the outdoor radiator is controlled by a three-way valve. The present invention mainly controls the water pump 1 in the battery pack circulating cooling water circuit. When the ambient temperature is not high or there is no refrigeration demand, the water pump is driven by an electric motor to pump coolant (a mixture of water and antifreeze) to complete the water circuit circulation of the two circuits, and dissipate heat through the outdoor radiator. When the battery pack or the motor and controller need to be cooled, the water pump will work at a high load, accelerate the number of coolant cycles in the water circuit, and fully reduce the water temperature to achieve the cooling effect. The water pump of modern cars is often integrated with the thermal management control system to adjust the working state of the water pump according to the real-time data of the temperature sensor. In order to make the working condition of the water pump 1 of the battery pack circulating cooling water circuit meet the optimal energy efficiency ratio (COP), the present invention adopts a more suitable control method. By inputting the ambient temperature and the compressor speed, the flow rate of the optimal energy efficiency ratio of the water pump under the working conditions is calculated. The specific algorithm is shown in the following formula:

[0048]

[0049] Where y Pump is the coolant flow rate; x R is the compressor speed.

[0050] Furthermore, the present invention illustrates the optimal energy efficiency ratio (COP) control strategy through specific embodiments:

[0051] When adjusting the condensing wind speed, HVAC air volume and the flow rate of the coolant circuit, the system COP can be improved, thereby improving the energy efficiency of the system. Under different ambient temperatures and compressor speeds, the maximum COP can be achieved by adjusting the condensing wind speed, HVAC air volume and the flow rate of the coolant circuit. The results are as follows: Figure 3 , 4 shown.

[0052] Based on this rule, a control strategy for fans, blowers and water pumps based on the optimal energy efficiency ratio is proposed. According to the results at an ambient temperature of 38°C, the Akima piecewise cubic Hermite interpolation method is used, and polynomial fitting is used to obtain the functional relationship between condensing wind speed, HVAC air volume, coolant flow, compressor speed, and COP. The functional relationship after fitting is shown in the following three equations. The mean square error (MSE) and root mean square error (RMSE) of the fitting are both within 1.5%, and the goodness of fit (R2) is greater than 0.99, indicating a high fitting accuracy. The visualization results are shown in Figure 5 shown.

[0053] In addition, the fan, blower and water pump control strategy based on the optimal energy efficiency ratio (COP) is to use the air volume, wind speed and flow rate corresponding to the maximum COP value at different compressor speeds as input to control the operation of the blower, fan and water pump when the passenger compartment and battery pack have cooling needs. Compared with the traditional fan control based on the condenser outlet pressure (1.5Mpa) and the blower and water pump control based on the target temperature (27℃ and 32℃), the results are as follows Figure 6 and Figure 7 As shown. The results show that the difference between the chiller cooling capacity and the condenser outlet pressure under the two control methods is small; when the compressor speed is 3000-5000Rmp / min, the control based on the optimal energy efficiency ratio (COP) can provide more cooling capacity for the evaporator compared with the traditional control method. And compared with the traditional control method, the system COP can be increased by 5.45%-14.69%.

[0054] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) The control method of the present invention is simple and efficient. In the setting of the overall control process, it is only necessary to perform input control according to the ambient temperature and the compressor speed. Compared with the individual control of the corresponding components in the traditional thermal management system, the demand for the controller and data collection is greatly reduced, the control mode is optimized, and the overall structure is simplified.

[0056] (2) The present invention adopts a control strategy with the optimal cost-effectiveness ratio (COP) as the goal, which can greatly improve the overall working efficiency of the system, reduce system energy consumption, and increase the cruising range of pure electric vehicles.

[0057] The control method of the present invention is collaborative control, which combines various low-voltage components, first finds out their respective optimal energy consumption ratios, and then performs collaborative control, so that the overall optimal energy consumption ratio of the system is greatly improved compared with traditional control methods.

[0058] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A thermal management control system for a fan water pump blower of a pure electric vehicle, characterized in that: It includes a refrigeration system module, a battery pack module, a motor electronic control cooling module and a cab module. The battery pack module and the cab module are connected in parallel to the refrigeration system module. The cab achieves the purpose of cooling by exchanging heat with the refrigerant through the compressor and evaporator components. The motor circuit and the battery pack circuit are heat exchanged by the coolant flowing through the outdoor radiator and heat exchanger. The fan, blower and water pump are all included in the refrigeration system module.

2. The thermal management control system of the fan water pump blower of a pure electric vehicle as claimed in claim 1, characterized in that: The fan is the fan of the outdoor radiator and condenser. When the high-temperature and high-pressure gaseous refrigerant flows out through the compressor and enters the outdoor radiator and condenser, in order to quickly cool it to liquid state, the fan needs to be turned on to exchange heat between the refrigerant and the external environment.

3. The thermal management control system of the fan water pump blower of a pure electric vehicle as claimed in claim 2, characterized in that: The blower is driven by a motor to suck in and push the air flow. The air inside the cabin is sucked in and pushed to the evaporator of the HVAC system through the rotation of the fan blades. Here, the refrigerant is compressed by a thermal expansion valve and converted into a low-temperature gaseous refrigerant, which is used to cool the air transmitted by the blower and then blown into the cabin to complete the refrigeration cycle.

4. The thermal management control system of the fan water pump blower of a pure electric vehicle as claimed in claim 3, characterized in that: The thermal management control system is provided with two water pumps, one is a water pump for controlling the circulating cooling water circuit of the battery pack, and the other is a water pump for controlling the cooling water circuit of the motor and controller.

5. A thermal management control method for a pure electric vehicle fan water pump blower, using the thermal management control system for the pure electric vehicle fan water pump blower as claimed in claim 4, characterized in that: The following steps are involved: Step 1: Collect the current ambient temperature T and compressor speed x R ; Step 2: Calculate the optimal energy efficiency ratio of the fan, battery pack circulating cooling water circuit control pump and blower under the current working conditions respectively; Step 3: Collaborative control outputs the optimal fan speed y fan , optimal pump speed y pump , optimal blower air volume y Hvac .

6. The thermal management control method for a fan water pump blower of a pure electric vehicle as claimed in claim 5, characterized in that: The calculation formula for the fan speed with the optimal energy efficiency ratio in step 2 is as follows: Where y Fan is the condensing wind speed of the fan; x R is the compressor speed.

7. The thermal management control method for a fan water pump blower of a pure electric vehicle as claimed in claim 1, characterized in that: The calculation formula for the optimal energy efficiency ratio of the blower speed in step 2 is as follows: COP Hvac =0.0047y Hvac -0.0005x R +2.9604 Where y Hvac is the HVAC air volume; x R is the compressor speed.

8. The thermal management control method for a fan water pump blower of a pure electric vehicle as claimed in claim 1, characterized in that: The calculation formula for the speed of the water pump with the optimal energy efficiency ratio in step 2 is as follows: Where y Pump is the coolant flow rate; x R is the compressor speed.

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