BATTERY COOLING CONTROL WITH ELECTRONIC EXPANSION ORGAN

Abstract

Vehicle (12) comprising: a refrigerant subsystem (52) comprising a radiator (90) and an electronic expansion valve EXV (92) arranged to selectively direct refrigerant to the radiator (90); a battery coolant subsystem (54) arranged to circulate coolant through a traction battery (24) and the radiator (90); and a control unit (100) configured to set the opening of the EXV (92) based on a difference between a measured radiator capacity and a setpoint radiator capacity, in response to the EXV (92) being open and a passenger compartment air conditioning request, wherein the battery coolant subsystem (54) further comprises coolant temperature sensors (110, 112) at the radiator inlet and outlet, and the measured radiator capacity is calculated based on signals received from the coolant temperature sensors (110, 112) at the radiator inlet and outlet.

Description

TECHNICAL FIELDThe present disclosure relates to a control strategy for operating a battery cooler associated with an air conditioning system of a vehicle.PRIOR ARTThe need to reduce fuel consumption and emissions in automobiles and other vehicles is well known. Vehicles are being developed that reduce or completely eliminate dependency on internal combustion engines. Electric and hybrid vehicles are a type of vehicle that is being developed in this respect. Electric and hybrid vehicles include a traction motor that is powered by a battery, i.e., a traction battery. Traction batteries require a thermal management system for thermally regulating the temperature of the battery cells.US 2012 / 0 205 088 A1 describes a vehicle air-conditioning system which is capable of carrying out a heating operation, wherein the use of an electric heater is reduced by using a further heat source, wherein the heat source is a ventilation waste heat recovery unit in the coolant circuit which recovers heat from the exhaust air from the vehicle interior, which can optionally be used in addition to the waste heat from the engine or from the battery and from the electric heater.DE 10 2017 108 778 A1 describes a traction battery cooling system for an electrified vehicle, which has a cooling circuit, a refrigerant circuit, a plurality of flow control valves and a control system which is designed to control the operation in such a way that interior cooling is prioritized over traction battery cooling.SUMMARYIt is an object of the present invention to provide improved thermal management in a vehicle, with which sufficient cooling of a drive battery of the vehicle is ensured even when passenger compartment air conditioning is required.This object is achieved with a vehicle according to claim 1.A climate control system for a vehicle includes a refrigerant subsystem having a radiator and an electronic expansion valve (EXV) arranged to selectively direct refrigerant to the radiator. The vehicle further includes a battery coolant subsystem having conduits arranged to circulate coolant through a traction battery and the radiator. The battery coolant subsystem further includes a first temperature sensor configured to measure coolant circulating into an inlet side of the radiator and a second temperature sensor configured to measure coolant circulating from an outlet side of the radiator. A controller, i.e., a vehicle controller, is configured to, responsive to the battery, i.e., the traction battery, exceeding a threshold temperature and passenger compartment air conditioning being requested, command an opening of the EXV to a predetermined position and adjust the position based on a measured coolant temperature difference between the first temperature sensor and the second temperature sensor.According to an embodiment, a vehicle includes a refrigerant system, i.e., a refrigerant subsystem having a radiator and an electronic expansion valve (EXV) arranged to selectively direct refrigerant to the radiator, and a coolant system, i.e., a coolant subsystem, i.e., a battery coolant subsystem arranged to circulate coolant through a traction battery and the radiator. A controller, i.e., a vehicle controller, is configured to, responsive to the EXV being opened and passenger compartment air conditioning being requested, adjust an opening of the EXV based on a difference between a measured radiator capacity and a desired radiator capacity, the battery coolant subsystem further comprising coolant temperature sensors at the radiator inlet and outlet, and the measured radiator capacity is calculated based on signals received from the coolant temperature sensors at the radiator inlet and outlet.A method of controlling a vehicle climate system includes a radiator arranged to transfer heat between a refrigerant subsystem and a battery coolant subsystem. The method includes opening an electronic expansion valve associated with the radiator and configured to control refrigerant to the radiator to a predetermined position in response to a battery, i.e., a traction battery, exceeding a threshold temperature. The method further comprises adjusting the position based on a measured coolant temperature difference between coolant temperatures at the radiator inlet and outlet.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic illustration of an example electric vehicle. FIG. 2 is a schematic illustration of a climate control system of a vehicle. FIG. 3 is a flow chart illustrating logic for controlling an electronic expansion valve associated with a battery cooler. FIG. 4 is another flow diagram illustrating logic for controlling an electronic expansion valve associated with a battery cooler.DETAILED DESCRIPTIONEmbodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Accordingly, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. It will be understood by one of ordinary skill in the art that various features illustrated and described with reference to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The illustrated combinations of features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desired for particular applications or implementations.FIG. 1 illustrates a schematic of an example battery electric vehicle (BEV). However, certain embodiments may also be implemented in the context of hybrid electric vehicles. The vehicle 12 includes one or more electric machines 14 mechanically connected to a transmission 16. The electric machines 14 may be capable of functioning as a motor or generator. If the vehicle is a hybrid electric vehicle, the transmission 16 is mechanically connected to an engine (not shown). The transmission 16 is mechanically connected to the wheels 22 via a drive shaft 20. The electric machines 14 may provide propulsion and deceleration capability. The electric machines 14 also function as generators and may provide fuel economy benefits by recovering energy through generator braking.A traction battery or battery pack 24 stores energy that may be used by the electric machines 14. The traction battery 24 typically provides a high voltage direct current (DC) output from one or more battery cell arrays, sometimes referred to as battery cell stacks, within the traction battery 24. The battery cell arrays may include one or more battery cells.The battery cells (such as prismatic cells, pouch cells, cylindrical cells, or any other type of cell) convert stored chemical energy to electrical energy. The cells may include a case, a positive electrode (cathode), and a negative electrode (anode). An electrolyte may allow ions to move between the anode and cathode during discharge and then return during recharging. Ports may allow current to flow out of the cell for use by the vehicle.Different battery pack configurations are available to meet individual vehicle variables including enclosure constraints and power requirements. The battery cells may be thermally regulated with a thermal management system. Examples of thermal management systems include air cooling systems, liquid cooling systems, and a combination of air and liquid cooling systems.The traction battery 24 may be electrically connected to one or more power electronics modules 26 through one or more contactors (not shown). The one or more contactors isolate the traction battery 24 from other components when open and connect the traction battery 24 to other components when closed. The power electronics module 26 may be electrically connected to the electric machines 14 and may provide the ability to bi-directionally transfer electrical energy between the traction battery 24 and the electric machines 14. For example, a typical traction battery 24 may provide a DC voltage while the electric machines 14 may require a three-phase alternating current (AC) voltage to function. The power electronics module 26 may convert the DC voltage to a three-phase AC voltage as required by the electric machines 14. In a regeneration mode, the power electronics module 26 may convert the three-phase AC voltage from the electric machines 14 functioning as generators to the DC voltage required by the traction battery 24.In addition to providing energy for propulsion, traction battery 24 may provide energy for other vehicle electrical systems. A typical system may include a DC-DC converter 28 that converts the high voltage DC output of the traction battery 24 to a low voltage DC power supply compatible with other vehicle components. Other high voltage loads, such as air conditioning compressors and electric heaters, may be directly connected to the high voltage supply without the use of a DC-DC converter module 28. In a typical vehicle, the low voltage systems are electrically connected to the DC-DC converter and an auxiliary battery 30 (e.g., a 12 volt battery).A battery energy control module (BECM) 33 may be in communication with the traction battery 24. The BECM 33 may function as a controller for the traction battery 24, and may also include an electronic monitoring system that manages the temperature and state of charge for each of the battery cells. The traction battery 24 may have a temperature sensor 31 such as a thermistor or other temperature indicator. The temperature sensor 31 may be in communication with the BECM 33 to provide temperature data related to the traction battery 24. The BECM 33 may be part of a larger vehicle control system that includes one or more additional controllers.The vehicle 12 may be recharged by an external power source 36. The external power source 36 may be a connection to a power outlet connected to the power grid or may be a local power source (e.g., solar power). The external power source 36 is electrically connected to a vehicle charging station 38. The charging station 38 may provide circuitry and controls to regulate and manage the transfer of electrical energy between the power source 36 and the vehicle 12.The external power source 36 may provide direct current or alternating current to the charging station 38. The charging station 38 may include a charging plug 40 for plugging into a charging port 34 of the vehicle 12. The charging port 34 may be any type of port configured to transfer energy from the charging station 38 to the vehicle 12. The charging port 34 may be electrically connected to a charging station or a vehicle-side power conversion module 32. The power conversion module 32 may condition the energy supplied from the charging station 38 to provide the proper voltage and current levels to the traction battery 24. The power conversion module 32 may interface with the charging station 38 to coordinate the delivery of energy to the vehicle 12. The charge station plug 40 may include pins that mate with corresponding recesses of the charge port 34. In other embodiments, the charging station may be an induction charging station. Here, the vehicle may include a receiver that communicates with a transmitter of the charging station to wirelessly receive electric power.The various components discussed include one or more controllers to control and monitor the operation of the components. The controllers may communicate via a serial bus (e.g., controller area network (CAN)) or via dedicated electrical lines. The controller generally includes any number of microprocessors, ASICs, ICs, memory (e.g., FLASH, ROM, RAM, EPROM, and / or EEPROM), and software code to cooperate with one another to perform a series of operations. The controller also includes predetermined data or "look-up tables" based on computations and test data and stored in the memory. The controller may communicate with other vehicle systems and controllers via one or more wired or wireless vehicle connections using common bus protocols (e.g., CAN and LIN). As used herein, reference to "a controller" refers to one or more controllers.The traction battery 24, the passenger compartment, and other vehicle components are thermally regulated with one or more thermal management systems. Exemplary thermal management systems are shown in the figures and described below. Referring to FIG. 2, the vehicle 12 includes a climate control system 50 having at least a refrigerant subsystem 52 and a battery coolant subsystem 54.Portions of the various thermal management systems may be disposed within various areas of the vehicle, such as the engine compartment and the passenger compartment.The refrigerant subsystem 52 provides passenger compartment air conditioning during some modes of operation and also cools and / or warms the battery 24 during some modes of operation. the refrigerant subsystem 52 may be a compression heat pump that circulates a refrigerant that transfers thermal energy to various components of the climate control system 50. The refrigerant subsystem 52 may include a cabin control loop 56 having a compressor 57, an exterior heat exchanger 58 (e.g., condenser), a first interior heat exchanger 60 (e.g., front evaporator), a second interior heat exchanger 62 (e.g., rear evaporator), a reservoir, fittings, valves, expansion devices, and other components commonly associated with refrigerant subsystems. The evaporators can each have an associated blower 61. The condenser 58 may be disposed behind the grille near the front of the vehicle, and the evaporators may be disposed within one or more HVAC housings. It is understood that heat exchangers referred to as "condensers" may also function as evaporators if the refrigerant subsystem 52 is a heat pump. A fan 59 may circulate air via the condenser 58.The components of the passenger compartment control loop 56 are connected in a closed loop by a plurality of conduits, pipes, hoses or cables. For example, a first conduit 64 connects the compressor 57 and the condenser 58 in fluid communication, a second conduit 66 connects the condenser 58 to the intermediate heat exchanger 82, and the conduit 67 connects the evaporators 60, 62 in fluid communication with the heat exchanger 82, the front evaporator 60 is connected to a conduit 67 via the conduit 68, and the rear evaporator 62 is connected to the conduit 67 via the conduit 70. A first expander 78 is disposed on the conduit 68 and controls the flow of refrigerant to the front evaporator 60 The expander is configured to change the pressure and temperature of the refrigerant in the subsystem 52. The expansion member 78 may be a thermal expansion valve having an electronically controllable shutoff feature or it may be an electronic expansion valve. A second expansion member 80 is disposed on the conduit 70 and controls the flow of refrigerant to the rear evaporator 62. The front evaporator 60 is connected via the line 74 to a return line 76, and the rear evaporator 62 is connected via the line 72 to the return line 76. The return line 76 establishes a connection between the heat exchanger 82 and the evaporators. A conduit 77 connects the heat exchanger 82 to the compressor 57. The intermediate heat exchanger 82 is optional.The climate control system 50 includes a controller 100 in electronic communication with a plurality of the climate control components. The dashed lines in FIG. 2 illustrate electrical connections between the controller 100 and the components. The controller may interface with the various components via a data bus or dedicated cables as described above. The evaporators 60, 62 each include a temperature sensor 84, 86, respectively, configured to send a signal indicative of the temperature of the corresponding evaporator to the controller 100. Using these temperature signals and other signals, the controller 100 may determine the operating conditions of the climate control system 50.The refrigerant subsystem 52 also includes a battery control circuit 89 that includes a radiator 90 and a third expansion element 92. The battery control loop 89 may include an inlet line 94 connected to the line 66 at the fitting 96 and connected to the refrigerant inlet side 101 of the radiator 90. The expansion element 92 can be located on the inlet line 94. The expansion member 92 is configured to change the pressure and temperature of the refrigerant flowing therethrough. The expansion element may be an electronic expansion valve (EXV) having a valve that changes a size of the opening within the EXV. The EXV may include an electronic actuator (e.g., stepper motor) configured to actuate the valve to increase or decrease the size of the aperture. The actuator is controlled by the controller 100. The controller 100 may command the actuator to place the expansion device in a wide open position, a fully closed position, or a throttled position. The throttled position is a partially open position in which the controller adjusts the size of the valve opening to regulate flow through the expander. The controller 100 and the expander may be configured to continuously or periodically adjust the throttled position in response to system operating conditions. By changing the opening within the expansion member, the controller can regulate the flow, pressure, temperature and condition of the refrigerant as needed. A return line 98 connects the battery radiator 90 to the passenger compartment control loop 56, the return line 98 being connected at one end to the radiator refrigerant outlet side 102 and at the other end to the line 76.The vehicle also includes a battery thermal management system that operates in a plurality of different modes, such as a battery heating mode or a battery cooling mode. The battery thermal management system includes a battery coolant subsystem 54 (shown) that dissipates heat to the refrigerant subsystem 52 via the radiator 90 and an auto-radiator control loop (not shown) that dissipates heat to ambient air via an auto-radiator. These two control loops may operate together or independently depending on the battery cooling requirements, ambient temperature, and other factors.The battery coolant subsystem 54 connects the traction battery 24 and the radiator 90 in fluid communication. The subsystem 54 includes a pump 104 disposed on a first conduit 106 that connects between the battery 24 and the coolant inlet side 114 of the radiator 90. A second conduit 108 connects between the coolant outlet side 116 and the battery 24. A coolant inlet temperature sensor 110 is disposed on the conduit 106 near the inlet side 114. The sensor 110 is configured to output a signal indicative of a temperature of the coolant circulating into the radiator 90 to the controller 100. A coolant outlet temperature sensor 112 is disposed on the conduit 108 near the outlet side 116. The sensor 112 is configured to output a signal to the controller 100 indicative of a temperature of the coolant exiting the radiator 90.The battery cooler 90 may be of any suitable design. For example, the radiator 90 may have a vortex cell, finned tube, or tube bundle configuration that facilitates the transfer of thermal energy without mixing the heat transfer fluids in the battery coolant subsystem 54 and the refrigerant subsystem 52.In systems where the battery cooler is in fluid communication with a passenger compartment air conditioning system (such as the refrigerant subsystem 52), a potential for adverse impact on the temperature of the passenger compartment is possible if the air conditioning system does not have sufficient capacity to cool both the passenger compartment and the battery at their respective loads. For example, during a hot day, cooling the battery and the passenger compartment simultaneously via the climate control system may result in the outlet temperature of the passenger compartment evaporator rising above a desired temperature, resulting in the air flowing into the passenger compartment being warmer than requested by the driver. Occupants of the passenger compartment may feel unsatisfactory if the passenger compartment temperature does not meet the demand temperature. Thus, in situations where the combined load exceeds the capacity, car manufacturers must choose to meet the demand for the passenger compartment and the demand for the battery, respectively.In one embodiment, the system is configured to balance the demand for the passenger compartment and the demand for the battery. Here, the controller is configured to determine a capacity of the air conditioning system for receiving battery heat (referred to herein as "radiator capacity"), and based on the radiator capacity, direct an appropriate amount of refrigerant through the radiator 90 to provide that capacity. In the illustrated embodiment, the EXV 92 is used to control the percentage of refrigerant flowing to the radiator 90 over the percentage of refrigerant bypassing the radiator via the conduit 68 or 70. Depending on the conditions of the passenger compartment air conditioning system 52, the EXV 92 may send any value between zero and 100 percent of the refrigerant to the radiator.If no chiller capacity is available, the battery coolant subsystem may attempt to cool the battery using an auto-chiller in conjunction with a fan. In some cases, the radiator and fan may not be able to achieve a sufficiently low battery coolant temperature for a particular battery load. To avoid overheating, the controller may limit the power of the battery to avoid overheating.The radiator capacity is the amount of thermal energy that passes between the refrigerant subsystem 52 and the battery coolant subsystem 54 within the radiator. The radiator capacity can be calculated using Equation 1: Q = ≅ · C p(| T ein- T aus|), where ≅ is the flow rate of the coolant, C p is the specific heat, T aus is the temperature of the coolant exiting the radiator, and T ein is the temperature of the coolant entering the radiator. A set point cooler capacity may be determined by a variety of different methods depending on the design philosophy. If, for example, the passenger compartment is prioritized, the setpoint value for the cooler capacity is determined by the refrigerant subsystem capacity minus the sum of all evaporator capacities. Alternatively, the radiator capacity could be set based on battery cooling requirements, or it can be set based on a capacity that is known not to increase the evaporator temperature beyond a threshold. For example, the refrigerant subsystem 52 may have a total capacity of 5000 watts (W) and the radiator capacity may be set at 1000 W, which as determined by vehicle tests does not increase the evaporator temperature beyond a threshold even at high loads of passenger compartment air conditioning. Of course, these values are not restrictive and vary depending on the refrigerant subsystem. The controller may include one or more look-up tables having a plurality of different chiller capacities used under different operating conditions.The control logic or functions performed by the controller 100 may be represented in one or more figures by flowcharts or similar diagrams. These figures provide representative control strategies and / or control logic that may be implemented using one or more processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Thus, various illustrated steps or functions may be performed in the illustrated order, in parallel, or in some cases omitted. Although not always expressly illustrated, one of ordinary skill in the art will recognize that one or more of the illustrated steps or functions may be repeatedly performed depending on the particular processing strategy being employed. Likewise, the order of processing is not necessarily required to achieve the features and advantages described herein, but is intended to facilitate illustration and description. The control logic may be implemented primarily in software executed by a microprocessor-based vehicle, engine, and / or powertrain controller, such as controller 100. Of course, depending on the particular application, the control logic may be implemented in software, hardware, or a combination of software and hardware in one or more controllers. In an implementation in software, the control logic may be provided in one or more computer readable storage devices or media having stored thereon data representing code or instructions executed by a computer for controlling the vehicle or its subsystems. The computer readable storage devices or media may include one or more of a number of known physical devices that electronically, magnetically, and / or optically store executable instructions and associated calibration information, operating variables, and the like.FIG. 3 is a flow chart 150 of an algorithm for controlling the EXV 92 when the battery is cooled by the radiator 90. At operation 152, control determines whether the traction battery temperature exceeds or corresponds to an upper threshold temperature. If not, the battery does not require cooling via the radiator and control returns to the beginning. If yes, the controller next determines whether passenger compartment air conditioning is requested by a vehicle occupant. If the air conditioning is OFF, control passes to operation 156, and the EXV 92 is actuated to a calibrated position based on the battery needs. If the air conditioning is ON, control passes to operation 158 and the controller determines whether a measured evaporator temperature exceeds or corresponds to a desired evaporator temperature. The desired evaporator temperature may be the upper limit temperature, such as between 6 and 10 degrees Celsius, which ensures that the refrigerant subsystem has the capacity to cool the passenger compartment. If the measured evaporator temperature is above the set temperature, the air flowing into the passenger compartment is warmer than is demanded by the occupants, which is undesirable. If the measured evaporator temperature exceeds the desired evaporator temperature, control passes to 160 and the EXV 92 is closed or remains closed since the refrigerant subsystem does not have any capacity to draw battery heat via the radiator 90. The vehicle may include other controllers that are used in emergency situations where battery cooling is prioritized over passenger compartment cooling. In these strategies, the EXV may be opened even though the evaporator temperature exceeds the set point.If yes at operation 158, control passes to operation 162 and control determines whether the EXV is open. If no, control passes to operation 164 and the radiator is activated to a calibrated position. The controller 100 may include one or more look-up tables that include a plurality of calibrated positions set to provide a desired radiator capacity. The desired cooler capacity may be based on the measured evaporator temperature from operation 158. The measured radiator capacity can also be based on the temperature difference between a setpoint battery temperature and the temperature of the coolant exiting the radiator (T aus). The desired radiator capacity is the expected temperature difference between the battery and T aus. If yes at operation 162, control passes to operation 166 and the position of the EXV is adjusted based on a temperature of the battery coolant, as described in more detail below.At operation 168, the controller measures a temperature (T ein) of the coolant entering the radiator, and at operation 170, the controller measures the temperature (T aus) of the coolant exiting the radiator. For example, the controller 100 receives signals from the temperature sensors 110 and 112, i.e., the coolant temperature sensors 110 and 112, to determine the measured temperatures of the coolant. At operation 172, the controller determines the flow of coolant in the battery coolant subsystem 54. the flow may be inferred from the pump 104, or the system may include a flow sensor. Using the measured values from operations 168-172, the controller is able to calculate a measured radiator capacity using Equation 1. At operation 174, the controller determines whether the measured radiator capacity exceeds or corresponds to the desired capacity. If yes, too much heat is transferred from the battery to the refrigerant subsystem. At operation 176, the opening of the EXV is adjusted based on the difference between the measured capacitance and the target capacitance (i.e., the opening is decreased). If no at operation 174, control passes back to operation 158 and control determines whether the measured evaporator temperature exceeds or corresponds to the desired evaporator temperature.If yes at operation 158, control passes to operation 166 since the EXV is already open. At operation 166, the controller actuates the EXV (i.e., opening of the EXV is increased) based on the difference between the measured capacity and the desired capacity. Once the EXV is actuated, control passes to operations 168-176. This algorithm may be repeated at predetermined intervals until the controls are terminated.FIG. 4 is a flow diagram 200 of another algorithm for controlling the EXV 92 when the battery is cooled by the radiator 90. This algorithm is similar to that of flowchart 150 in that the controller adjusts the position of the EXV based on the temperature of the coolant. At operation 202, control determines whether the traction battery temperature exceeds or corresponds to a threshold temperature. If no, no battery cooling by the radiator is required and control passes to BEGIN. If so, control passes to operation 204 and control determines whether the passenger compartment air conditioning is ON. If the air conditioning is OFF, control passes to operation 205 and the EXV is actuated to a calibrated position based on the battery demand. If the air conditioning is ON, control passes to operation 206 and the controller determines whether the measured evaporator temperature is within a temperature operating range. If the sensed evaporator temperature is too hot or too cold, control returns to the beginning.If the measured evaporator temperature is within the operating range, control passes to operation 208. Rather than programming the controller to compare a measured radiator capacity to a desired radiator capacity to control the EXV 92, the controller may be programmed to calculate a desired temperature difference between coolant T ein entering the radiator and coolant T aus exiting the radiator using Equation 1, using a desired radiator capacity as Q. Since Q, p (the pump may have a single speed, making a constant, or could be determined prior to operation 208) and C are constants, the controller may determine a set point |T ein- T aus| which occurs at operation 208. The target temperature difference may be determined based on the optimal battery operating temperature (OptBat) and the temperature of the coolant exiting the radiator (T aus). In one embodiment, the target temperature difference OptBat-T is aus.At operations 210 and 212, the controller measures coolant temperatures via the sensors and determines T aus and T ein. At operation 216, the controller determines whether the measured temperature difference exceeds or corresponds to the desired temperature difference. If so, the opening of the EXV 92 is decreased based on |T ein- T aus| at operation 218. If no, the opening of the EXV is increased based on |T ein- T aus| at operation 220.While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The terms used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments may be combined to form further embodiments of the invention that may not be expressly described or illustrated. Although various embodiments may be described as providing or being preferred over other embodiments or implementations in the art with respect to one or more desired characteristics, one of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the particular application and implementation. These attributes may include, but are not limited to, cost, strength, life span, life cycle cost, marketability, appearance, packaging, size, operability, weight, magnetoresistance, ease of assembly, etc. Therefore, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more properties are not outside the scope of the disclosure and may be desirable for particular applications.

Claims

A vehicle (12) comprising: a refrigerant subsystem (52) comprising a radiator (90) and an electronic expansion valve EXV (92) arranged to selectively direct refrigerant to the radiator (90); a battery coolant subsystem (54) arranged to circulate coolant through a traction battery (24) and the radiator (90); and a controller (100) configured to, responsive to the EXV (92) being open and passenger compartment air conditioning being requested, adjust an opening of the EXV (92) based on a difference between a measured radiator capacity and a desired radiator capacity, wherein the battery coolant subsystem (54) further comprises coolant temperature sensors (110, 112) at the radiator inlet and outlet and the measured radiator capacity is calculated based on signals received from the coolant temperature sensors (110, 112) at the radiator inlet and outlet.The vehicle (12) of claim 1, wherein the controller (100) is further programmed to open the EXV (92) to a predetermined position in response to the traction battery (24) exceeding a threshold temperature.The vehicle (12) of claim 1, wherein the opening of the EXV (92) is increased in response to the measured radiator capacity being below the desired radiator capacity.The vehicle (12) of claim 3, wherein the opening of the EXV (92) is decreased in response to the measured radiator capacity exceeding the desired radiator capacity.

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