A vehicle evaporative condenser de-icing method and system based on a heat pump device

Abstract

The application discloses a vehicle evaporative condenser deicing method based on a heat pump device: a triggering step: the vehicle is normally driven, and the working mode of the heat pump device meets the requirements to start acquiring the vehicle parameters in real time and judging: a judging step: acquiring the outdoor environment temperature, and judging whether the difference between the refrigerant saturation temperature under the evaporative pressure meets the preset condition, if yes, determining that the current is icing; an entering step: if the current icing meets the deicing condition, deicing operation is performed; a deicing step: when the deicing operation, the heat pump device enters the MainMode_DeIce_111 mode, and the water heater of the heat pump device starts to work. The application can accurately and timely judge the icing of the outdoor heat exchanger and quickly and effectively deice after icing, thereby not affecting other various thermal comfort requirements (including cabin, motor and battery) on the vehicle, and improving the automobile performance and driving comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile thermal management, in particular to a new energy vehicle heat pump system deicing control technology during heat pump system operation. BACKGROUND

[0002] Modern automobile new technology develops rapidly, new energy vehicle is widely popular, the pursuit of endurance mileage is always a positive topic, various technologies for improving endurance are continuously adopted, heat pump technology is an effective way to improve low-temperature endurance, various forms of heat pump are presented, air source heat pump is widely used as a high-efficiency heat pump form, its basic situation is: the system contains compressor / condenser (water-cooled or built-in air-cooled condenser), electronic expansion valve / evaporative condenser, in low-temperature heating condition (generally above-10℃), the electronic expansion valve throttles, the refrigerant evaporates in the evaporative condenser to absorb heat from the external environment, and then works through the compressor to the water-cooled condenser or the built-in air-cooled condenser to transfer to the cabin or the battery to provide heating demand heat, the energy efficiency of one version is about 1.8~2.2, which effectively saves energy.

[0003] For example, the publication number is CN109341151A, the publication date is 2019-02-15, and the patent name is "Electric vehicle air source heat pump control device", the disclosed electric vehicle air source heat pump control device has a refrigerant inlet and outlet, a cooling liquid inlet and outlet in the liquid-cooled condenser to realize heat exchange; the air conditioner main machine assembly has an evaporator and a heater, and the air conditioner compressor is connected with a gas-liquid separator; the refrigerant circuit includes a refrigerant inlet and a refrigerant outlet, and the air conditioner compressor, the outdoor heat exchanger, the gas-liquid separator and the evaporator arranged therebetween and connected; and the cooling liquid circuit includes a cooling liquid inlet and a cooling liquid outlet, and the heater arranged therebetween and connected.

[0004] However, in various external environment conditions, the actual heat pump system operation process, the surface temperature of the evaporative condenser is always lower than the ambient temperature, in the case of high humidity in the external air, ice will appear on the surface of the evaporative condenser, once the ice is formed, the heat pump system cannot work normally, and needs to be stopped and defrosted under appropriate conditions, at this time, the cabin or battery demand can only be provided by auxiliary heat sources such as HVH or PTC, and the purpose of saving energy cannot be achieved, therefore, it is very important to keep the outdoor heat exchanger of the heat pump system from icing or to quickly defrost after icing. SUMMARY

[0005] The present application relates to the field of automobile thermal management, in particular to a new energy vehicle heat pump system deicing control technology during heat pump system operation.

[0006] In order to achieve the above object, the technical scheme adopted by the present application is as follows: A vehicle evaporative condenser deicing method based on a heat pump device:

[0007] Triggering step: the vehicle is normally running, and the working mode of the heat pump device meets the requirements to start real-time acquisition and judgment on the vehicle parameters:

[0008] Judgment step: whether the difference between the outdoor environment temperature and the refrigerant saturation temperature under the evaporation pressure meets the preset condition, if yes, it is determined that the current is icing;

[0009] Entry step: whether the current icing acquisition meets the deicing condition, if yes, deicing operation is performed;

[0010] Deicing step: when the deicing operation, the heat pump device enters MainMode_DeIce_111 mode, and the water heater of the heat pump device starts to work, MainMode_DeIce_111 is the state that the waterway system three-way valve is opened and hot water enters the front end radiator.

[0011] The judgment step is to simultaneously meet: the current vehicle speed > 0, and the heat pump device mode is in MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108, the MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108 mode is that the refrigerant system is in heat pump heating or heat pump double heating mode.

[0012] The judgment step: if the outdoor environment temperature ≤ 0℃, and the difference between the refrigerant saturation temperature under the evaporation pressure > 7℃, start timing T1, otherwise do not perform deicing operation;

[0013] If the timing time ≥ 40min, it is determined that the current is icing.

[0014] The entry step needs to meet: the vehicle speed = 0 and lasts for ≥ 5min, the motor cooling level is in LV0 / 1 / 2, and there is no heating request for the battery.

[0015] The deicing step: (3WV1:V2V3(0%), 3WV3:V2V1(33%), 3WV2:V1V3(100%), CWP1:94%, MWP3: execute according to the motor cooling level request, BWP2: execute according to the battery level request), HVCH outlet water temperature = 65℃, and operation time T2 = 7min.

[0016] T2>2min or HVCH outlet water temperature = 50℃, Fan = 75%;

[0017] T2>4min, Fan=100%, AGS=75%.

[0018] Further comprising an exit step, obtaining the water heater outlet water temperature to determine the fan, AGS and running time to determine.

[0019] The exit step meets any of the following conditions:

[0020] 1) T2=7min, flag bit T1, T2 clear 0, DTC becomes historical fault;

[0021] 2) Motor cooling level: LV3 / 4, or battery request heating, or Vspd>0, exit flag bit T2 clear 0, but T1 is not clear 0, DTC historical fault is retained.

[0022] A vehicle evaporative condenser deicing system based on a heat pump device, the system is provided with a controller, the controller connects the vehicle CAN network and the heat pump device to obtain the vehicle speed, the environment temperature, the low pressure side pressure, the heat pump working mode, and outputs the control instruction to the water heater of the heat pump device of the heat pump device.

[0023] The controller is a TDU or CLM on the vehicle that executes the deicing method.

[0024] The present application can accurately and timely determine the icing of outdoor heat exchanger and quickly and effectively deice after icing, so as to not affect other various thermal comfort requirements (including cabin, motor, battery) on the vehicle, and improve the performance and driving comfort of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0025] The content expressed in each drawing in the specification of the present application is briefly described as follows:

[0026] Figure 1 Evaporative condenser icing / deicing strategy parameter input / output schematic diagram;

[0027] Figure 2 Evaporative condenser icing / deicing control strategy flow chart. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be further described in detail below with reference to the drawings, and the shape, structure, mutual position and connection relationship between parts, the action and working principle of each part, the manufacturing process and the operation and use method of each component involved in the specific embodiments of the present application will be described in further detail, to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present application.

[0029] In a certain EV model, the heat management scheme adopts an air source indirect heat pump system (with motor battery waste heat recovery). In heat pump mode, the compressor works through the water-cooled condenser, through the coaxial tube plate exchange through the electronic expansion valve 1, through the indoor evaporator (preheat indoor cold air), and then through the TXV throttling to the outdoor evaporative condenser. After heat absorption, the overheated plate exchange low pressure side returns to the compressor suction side, and operates according to this cycle principle.

[0030] In the actual driving process of the vehicle, the environment temperature and the saturation temperature under the real-time evaporation pressure of the refrigerant in the external heat exchanger form the working heat exchange environment of the outdoor heat exchanger. Therefore, the environment temperature and the saturation temperature under the real-time evaporation pressure are taken as the target for judging whether the outdoor heat exchanger can work normally. Once it cannot work normally, the vehicle driving condition is associated to simply judge the demand situation of the cabin personnel. At this time, the motor / battery demand situation is judged according to the demand signal of the motor / battery itself. Because in the actual running process, the icing process and the deicing process have a time process, and are associated with the water temperature, therefore, the time and the water temperature are taken as the reference conditions for judging after entering the deicing mode. After the overall judgment, the system running mode, the fan / AGS running condition and the HVH water temperature are controlled, and the respective signal duty cycle is taken as the output form, as shown in Figure 1 .

[0031] As shown in Figure 2 , in the actual process, the sensor collects data in the control, the ECU (engine control unit) / THCU (hybrid system control unit) calculates and judges the data, and finally outputs the PWM signal. The control strategy flow chart is explained as follows:

[0032] Vehicle normal operation process:

[0033] The heat pump system provides a heat source in a low temperature environment, and the mode is in: MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108.

[0034] 1) Icing judgment

[0035] a) Determine the icing condition according to the difference between the outdoor environment temperature and the refrigerant saturation temperature under the outdoor environment temperature-evaporation pressure.

[0036] 2) Deicing judgment

[0037] a) Determine whether it is allowed to enter the work according to the vehicle speed.

[0038] b) Determine whether it is allowed to enter the work according to the motor demand level (L1 / L2) and the battery demand.

[0039] 3) Deicing operation

[0040] a) Determine to enter de-icing operation according to the mode signal MainMode_DeIce_111 and start HVCH operation.

[0041] b) Determine the fan, AGS and running time according to the HVCH outlet water temperature.

[0042] According to the above outdoor heat exchanger icing / de-icing strategy block diagram, its control logic and parameters are developed for its icing / de-icing conditions, which are described in detail as follows:

[0043] Triggering conditions:

[0044] Determine in order as follows: ① if Vspd>0, and the mode is in MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108

[0045] ② if Tamb≤0℃&(Tamb- SatT(LP))>7℃(icing risk), increase the timer to start timing T1;

[0046] ③ if Tamb≤0℃&(Tamb- SatT(LP))≤7℃(no icing risk), do not time;

[0047] ④ if Tamb>0℃(environmental de-icing); timer T1->condition 3, stop timing->condition 4, single 2s(cumulative),

[0048] if T1>40min, issue DTC icing;

[0049] Enter execution:

[0050] if Vspd=0, and lasts≥5min, and motor cooling level: LV0 / 1 / 2, and no battery heating request; enter de-icing mode MainMode_DeIce_111(3WV1:V2V3(0%), 3WV3:V2V1(33%), 3WV2:V1V3(100%), CWP1:94%, MWP3: execute according to the motor cooling level request, BWP2: execute according to the battery level request), HVCH outlet water temperature=65℃, running time T2=7min

[0051] ① T2>2min or HVCH outlet water temperature=50℃, Fan=75%;

[0052] ② T2>4min, Fan=100%, AGS=75%

[0053] In short, upon entering execution, the positions of the three water valves are as follows: 3WV1:V2V3 (0%), 3WV3:V2V1 (33%), 3WV2:V1V3 (100%); the duty cycles of the three water pumps are as follows: CWP1:94%, MWP3: Execution according to motor cooling level, BWP2: Execution according to battery level; HVCH outlet water temperature is 65℃, and the running time T2=7min;

[0054] Exit conditions:

[0055] ① When T2 = 7min, the flag bits T1 and T2 are cleared to 0, and the DTC becomes a historical fault;

[0056] ② Motor cooling level: LV3 / 4, or battery requests heating, or Vspd>0, when exiting, flag T2 is cleared to 0, but T1 is not cleared to 0, and DTC historical faults are retained.

[0057] Execute after exiting: Maintain the previous system mode.

[0058] For heat pump devices, the de-icing control system and strategy collect air conditioning pressure signals, vehicle speed signals, engine water temperature signals, and three-electric system water temperature signals. Through logical judgment and comparison selection, it formulates a system to prevent the outdoor evaporative condenser from freezing in low-temperature environments and to de-ice in a timely manner after freezing. In this simple and efficient way, the de-icing work can be completed without the need for additional equipment and electronic components, thus constituting a low-cost, high-efficiency, and precise vehicle evaporative condenser de-icing system and method.

[0059] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for de-icing a vehicle evaporative condenser based on a heat pump device, characterized in that: Triggering steps: The vehicle is running normally, and the heat pump device's operating mode meets the requirements. Real-time acquisition and analysis of vehicle parameters then commences. Judgment steps: Obtain the outdoor ambient temperature and whether the difference between the refrigerant saturation temperature under evaporation pressure meets the preset conditions. If it does, determine that icing is currently occurring. Entry steps: Check if the current ice condition meets the de-icing requirements; if it does, proceed with the de-icing operation. De-icing step: During the de-icing operation, the heat pump device enters MainMode_DeIce_111 mode, and the water heater of the heat pump device starts to work. MainMode_DeIce_111 means that the three-way valve of the water system is open, and hot water enters the front-end radiator. The judgment step is based on the simultaneous satisfaction of: current vehicle speed > 0, and the heat pump device mode being MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108, where MainMode_HP_77 / MainMode_HP_79 / MainMode_HPBatHeat_108 modes all indicate that the refrigerant system is in heat pump heating or heat pump dual heating mode; The judgment step is as follows: if the outdoor ambient temperature is ≤0℃ and the difference between the refrigerant saturation temperature under the evaporation pressure and the temperature is >7℃, then start timing T1; otherwise, the defrosting operation is not performed. If the timer duration is ≥40 minutes, then the current state is considered frozen. The entry step requires that the vehicle speed = 0 and last for ≥ 5 minutes, the motor cooling level be LV0 / 1 / 2, and the battery have no heating request. The de-icing steps are as follows: (3WV1:V2V3(0%), 3WV3:V2V1(33%), 3WV2:V1V3(100%), CWP1:94%, MWP3: execute according to motor cooling level requirements, BWP2: execute according to battery level requirements), HVCH outlet water temperature = 65℃, running time T2 = 7min; T2 > 2 min or HVCH outlet water temperature = 50℃, Fan = 75%; T2>4min, Fan=100%, AGS=75%.

2. The vehicle evaporative condenser de-icing method based on a heat pump device according to claim 1, characterized in that: It also includes an exit step, which uses the water heater outlet water temperature to determine the fan, AGS, and running time for judgment.

3. The vehicle evaporative condenser de-icing method based on a heat pump device according to claim 2, characterized in that: The exit step satisfies any of the following conditions: 1) When T2 = 7 minutes, reset timers T1 and T2 to 0, and DTC becomes a historical fault; 2) Motor cooling level: LV3 / 4, or the battery requests heating, or Vspd>0, timer T2 is cleared to 0 when exiting, but T1 is not cleared, and DTC historical faults are retained.

4. A vehicle evaporative condenser de-icing system based on a heat pump device, characterized in that: The system is equipped with a controller, which connects to the vehicle's CAN network and the heat pump device to obtain vehicle speed, ambient temperature, low-pressure side pressure, and heat pump operating mode, and outputs control commands to the water heater of the heat pump device. The controller is a TDU or CLM on the vehicle that performs the de-icing method as described in any of claims 1-3.

Images