Climate control system for a vehicle

Abstract

Vehicle (10), comprising: a refrigerant system (50) comprising an intermediate heat exchanger (126), an external heat exchanger (66) and an intermediate expansion device (84) as well as a bypass loop (88) for bypassing the external heat exchanger (66); a coolant circuit comprising an auxiliary pump (114) designed to circulate coolant through the intermediate heat exchanger (126) and a power unit (14); and a control unit (100) which is programmed to open the expansion device (84) and switch off the auxiliary pump (114) and to close a bypass valve (90) so that all the refrigerant flows through the external heat exchanger (66) to condense refrigerant in the external heat exchanger (66) in response to a request for air conditioning and when the refrigerant temperature exceeds a threshold temperature.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a control strategy for operating the vehicle during an air conditioning mode. BACKGROUND

[0002] The need to reduce fuel consumption and emissions in automobiles and other vehicles is well known. Currently, vehicles are being developed that reduce or completely eliminate reliance on internal combustion engines. Electrified vehicles are one type of vehicle currently being developed for this purpose. Generally, electrified vehicles differ from conventional motor vehicles in that they are specifically powered by one or more battery-driven electric motors. Many electrified vehicles incorporate thermal management systems that manage the heat requirements of various components during vehicle operation, including the vehicle's high-voltage traction battery and the internal combustion engine (if present).

[0003] DE 10 2011 100 198 A1 discloses a heat pump circuit system. US 4 539 943 A discloses a cooling system for a power engine. US 2005 / 0061 011 A1 discloses a device for a cooling circuit. SUMMARY

[0004] According to one embodiment, a vehicle comprises a refrigerant system having an intermediate heat exchanger, an external heat exchanger, and an expansion device located between them, as well as a bypass loop for bypassing the external heat exchanger. The vehicle also includes a coolant circuit with a pump designed to circulate coolant through the intermediate heat exchanger and a motor. A controller is programmed to open the expansion device and shut off the pump, and to close a bypass valve so that all the refrigerant flows through the external heat exchanger to condense in the external heat exchanger, in response to a request for air conditioning and when the coolant temperature exceeds a threshold temperature.

[0005] According to a further embodiment, a vehicle comprises a motor and a traction battery electrically connected to at least one electric machine. A refrigerant system of the vehicle comprises an external heat exchanger, an intermediate heat exchanger, an expansion device arranged between the heat exchangers, and a bypass loop having an inlet arranged between the heat exchangers and configured to bypass the external heat exchanger. A coolant circuit of the vehicle comprises a pump designed to circulate coolant through the motor and the intermediate heat exchanger. Grille closure flaps are arranged behind a front panel of the vehicle and in front of the external heat exchanger.A control system is programmed to close the expansion device in response to a request for air conditioning and when the refrigerant temperature is below a threshold temperature, allowing the refrigerant to bypass the external heat exchanger via the bypass loop, and to switch on the pump to transfer heat from the refrigerant system to the coolant circuit via the intermediate heat exchanger, causing refrigerant to condense in the intermediate heat exchanger.

[0006] According to yet another embodiment, a method for operating a climate control system is disclosed. The vehicle comprises grille shutter flaps and a heat exchanger connected to a cooling system, as well as an engine cooling loop containing coolant. The method includes, in response to a request for air conditioning and the coolant temperature being below a threshold temperature, transferring heat from the cooling system to the engine cooling loop via the heat exchanger and closing the grille shutter flaps. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic diagram of an example hybrid electric vehicle. Fig. Figure 2 is a perspective view of a grill closure flap arrangement. Fig. 3 is a schematic diagram showing various thermal management systems of the in Fig. 1 represents the vehicle shown. Fig. 4 is the schematic diagram of the Fig. 3, which is shown in a second air conditioning mode. Fig. 5 is a control strategy for selecting between a first and second climate control mode of the vehicle. Fig. 6 is a control strategy for switching from the second air conditioning mode to the first air conditioning mode. Fig. 7 is another control strategy for choosing between a first and a second climate control mode of the vehicle. DETAILED DESCRIPTION

[0007] Here, embodiments of the present disclosure are described. It is understood, however, that the disclosed embodiments are merely examples and that other embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed here should therefore not be interpreted as limiting, but merely as a representative basis for teaching a person skilled in the art how the present invention can be used in various ways.It is understood by the average person skilled in the art that various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to create embodiments not explicitly illustrated or described. The combinations of illustrated features provide representative embodiments for typical applications. However, various combinations and modifications of the features, consistent with the teachings of this disclosure, may be desirable for certain applications or implementations.

[0008] Fig. Figure 1 shows a diagram of a typical plug-in hybrid electric vehicle. Certain embodiments can also be implemented in connection with non-plug-in hybrid electric vehicles. With reference to the Fig. 1. A vehicle 10 comprises a powertrain 12, such as a power-split powertrain, which includes a first drive system and a second drive system. The first drive system comprises a power engine 14 and a first electric machine or generator 16. The second drive system comprises a second electric machine 18 or motor, the generator 16, and a traction battery 20. The first and second drive systems generate torque to drive one or more of the driven wheels 22 of the vehicle.

[0009] The power machine 14, e.g., an internal combustion engine, and the generator 16 can be connected to each other by a power transmission unit 24. The power transmission unit 24 can be a planetary gear set comprising a ring gear 26, a sun gear 28, and a carrier assembly 30. Other types of power transmission units are considered in this disclosure. The drive train 12 can include additional gear ratios 32 for coupling the generator 16 to the electric machine 18 and for coupling the generator and / or the engine to the differential 34 in order to distribute the torque to the wheels 22.

[0010] The vehicle 10 also includes a battery energy management module (BECM) for controlling the traction battery 20. The BECM receives input indicating certain vehicle and battery states, such as battery temperature, voltage, and current. The BECM calculates and estimates battery parameters, such as the battery state of charge (SOC) and battery performance. The BECM provides output indicating the battery state of charge (SOC) and battery performance to other vehicle systems and controllers.

[0011] Vehicle 10 incorporates multiple controllers for managing the function of various components. These controllers can communicate via a serial bus (e.g., Controller Area Network (CAN)) or dedicated electrical lines. A controller generally comprises any number of microprocessors, ASICs, ICs, memory (e.g., FLASH, ROM, RAM, EPROM, and / or EEPROM), and software code that work together to perform a range of operations. The controller also includes predefined data, or "reference tables," based on calculations and test data, stored within memory. The controller can 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). In the sense used here, a reference to "a controller" can refer to one or more controllers.

[0012] The hybrid electric vehicle 10 can operate in several different powertrain modes, including charge maintenance mode and charge depletion mode (also known as EV mode). In charge depletion mode, the battery is used as the primary source of power until the battery state of charge (SOC) drops below a threshold level, at which point the vehicle switches to charge maintenance mode. The term "charge depletion mode" as used here refers to modes in which the motor may run periodically and modes in which the motor is not used. For example, the vehicle may have a pure EV mode (also known as "EV now") in which the motor is deactivated.

[0013] With reference to the Fig. 2 The vehicle 10 comprises a front fairing with a grille. Grille closure flaps 40 are located in the engine compartment behind the grille and in front of the engine 14. The grille closure flaps 40 comprise a front fairing 41, which is attached to one or more vehicle body structures behind the front fairing of the vehicle 10. The front fairing 41 defines at least one opening 42. Several flaps 43 are pivotally attached to the front fairing 41 and are located in one or more of the openings 42. Each of the flaps 43 is movable between an open position, a closed position, and several intermediate positions via an actuator 44. The actuator 44 may include a motor that is electrically controlled by the control unit. For illustrative purposes, the upper row of flaps is shown in the open position, and the lower row of flaps is shown in the closed position.In some embodiments, the upper and lower rows of flaps operate interdependently, and in other embodiments, the upper and lower rows operate independently. Each of the flaps 43 also has a broad side 47 and a narrow side 45. In the closed position, each of the flaps 43 is oriented so that the broad side 47 faces the airflow to prevent air from entering through the openings 42. In the open position, each of the flaps is oriented so that the narrow side 45 faces the airflow to allow air to flow through the openings 42. The openings 42 and the flaps 43 work together to define an effective cross-sectional area through which air can flow. The size of the effective cross-sectional area can be increased or decreased by adjusting the flaps.

[0014] The traction battery 20, the passenger compartment, and other vehicle components are thermally controlled by one or more thermal management systems. Exemplary thermal management systems are shown in the figures and described below. With reference to the Fig. 3. The vehicle 10 comprises a passenger compartment 46 and an engine compartment 48, which are separated by a firewall 49. Parts of the various thermal management systems may be located in the engine compartment, in the passenger compartment, or in both. The vehicle 10 includes a refrigerant system 50 with a refrigerant subsystem 52, a passenger compartment heating subsystem or passenger compartment loop 54, and a ventilation subsystem 56.

[0015] The ventilation subsystem 56 can be located within the dashboard of the passenger compartment 46. The ventilation subsystem 56 includes an HVAC housing 58, which has an air inlet and an air outlet. The outlet side is connected to ducts that distribute outgoing air into the passenger compartment. A blower motor drives a fan (or a passenger compartment blower) 60 to circulate air within the ventilation subsystem 56. A mixing flap 59 is located in the housing to control the temperature of the air exiting the HVAC housing 58. The vehicle 10 may also include a battery thermal management system (not shown) to control the temperature of the traction battery 20.

[0016] The refrigerant subsystem 52 serves to provide air conditioning for the passenger compartment during some operating modes. The refrigerant subsystem 52 also serves to cool the traction battery 20 during some operating modes and to heat the battery during other operating modes. The refrigerant subsystem 52 can be a vapor-compression refrigerant subsystem that circulates a refrigerant which transfers thermal energy to various components of the refrigerant system 50. The refrigerant subsystem 52 can include a passenger compartment loop with a compressor 64, an external heat exchanger 66 (which is typically a condenser), an internal heat exchanger (which is typically an evaporator 68), a pressure accumulator 70, connectors, valves, and expansion devices. The compressor can be an electronic compressor.The heat exchanger 66 can be located behind the grille flaps 40 near the front of the vehicle, and the evaporator 68 can be located inside the HVAC housing 58. It is understood that heat exchangers designated as "condensers" can also function as evaporators in some modes. In one embodiment, the refrigerant subsystem 52 is a heat pump that can be used for both cooling and heating the passenger compartment.

[0017] The passenger compartment loop components are connected by several lines, pipes, hoses, or tubing. For example, a first line 72 connects the compressor 64 and the heat exchanger 66 so that they are in fluid communication; a second line 74 connects the heat exchanger 66 to a valve 82; a third line 76 connects the heat exchanger 66 and the evaporator 68 so that they are in fluid communication; and a fourth line 78 connects the evaporator 68 and the compressor 64 so that they are in fluid communication. An evaporator bypass line 80 is connected between the valve 82 and line 78. The valve 82 can be a solenoid valve that can be opened and closed to supply refrigerant to either line 76 or the evaporator bypass line 80, depending on the operating mode of the refrigerant subsystem 52.For example, when the air conditioner is switched on, refrigerant is routed to line 76 and not to the evaporator bypass line 80. Valve 82 can be connected to a controller 100. A heat exchanger 79 is provided to transfer thermal energy between line 76 and line 78.

[0018] A first expansion device 84 can be arranged on line 72, and a second expansion device 86 can be arranged on line 76. The expansion devices are designed to change the pressure and temperature of the refrigerant in the refrigerant subsystem 52. The expansion devices can include an electronic actuator controlled by the controller 100. The controller 100 can instruct the actuator to position 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 modulates the size of the valve opening to regulate the flow through the expansion device. The controller 100 and the expansion devices can be designed to modulate the throttled position continuously or periodically in response to system operating conditions.By changing the opening in the expansion device, the controller can regulate the flow rate, pressure, temperature, and condition of the refrigerant as needed. In alternative embodiments, a thermally controlled expansion device (TXV) or a capillary tube with shut-off valves can be used instead of the electronically controlled expansion devices.

[0019] According to the invention, the refrigerant subsystem 52 also includes a bypass loop 88 for bypassing the external heat exchanger 66. A bypass valve 90 arranged on the bypass loop 88 is actuated to selectively allow refrigerant flow through the bypass loop 88. The bypass valve 90 can be a solenoid valve electronically controlled by the controller 100. The bypass valve 90 and the expansion device 84 work together to circulate refrigerant either through the external heat exchanger 66 or through the bypass loop 88. The refrigerant subsystem 52 can include a battery loop (not shown) comprising a further evaporator (generally referred to as a cooling device) and a third expansion device for temperature control of the battery.

[0020] The passenger compartment loop 54 contains a heating heat exchanger 110, an auxiliary pump 114, a valve 116, and a line forming a closed loop for circulating coolant, such as an ethylene glycol mixture. Coolant can be circulated, for example, from the auxiliary pump 114 via line 122 to the heating heat exchanger 110. The heating heat exchanger 110 is connected to the valve 116 via line 124. The valve 116 is connected to the auxiliary pump 114 via line 128. The valve 116 can be a solenoid valve electronically controlled by the controller 100. A temperature sensor 118 can be located on line 122.

[0021] The engine 14 is thermally controlled by an engine cooling loop 130, which is configured to circulate coolant—such as an ethylene glycol mixture—through the engine 14. The engine cooling loop 130 comprises a radiator 132, a thermostat 134, and an engine coolant pump 136 (also known as a water pump), which are interconnected by several lines to form a coolant circuit. The engine cooling loop 130 and the passenger compartment loop 54 can be selectively connected to form a single coolant circuit during some operating modes and selectively disconnected to form separate coolant circuits during other modes.

[0022] The engine coolant pump 136 can be connected to an inlet port of the engine 14 via line 138. The engine coolant pump 136 can be powered by electricity supplied by the traction battery 20 or another power source. The outlet port of the engine 14 can be connected to line 128 of the passenger compartment loop 54 via line 140. An inlet of the radiator 132 can be connected to line 140 via line 142. An outlet of the radiator 132 is connected to the thermostat 134 via line 144. The thermostat 134 is connected to the engine coolant pump 136 via line 146. The engine cooling loop 130 also includes a radiator bypass 148. Depending on the coolant temperature, the thermostat 134 controls whether coolant is directed to the radiator 132 or to the radiator bypass 148.

[0023] The thermostat 134 can be electronically or mechanically controlled. The thermostat 134 can be connected to the valve 116 via line 150. The illustrated arrangement of the engine cooling loop 130 is merely an example, and many other arrangements are considered in the present disclosure. In some embodiments, a further temperature sensor can be arranged on line 140. Or the coolant temperature on line 140 can be derived based on the engine temperature. The passenger compartment loop 54 can also include an electric heater arranged on line 122.

[0024] The passenger compartment loop 54 can exchange thermal energy with the refrigerant subsystem 52 via an intermediate heat exchanger 126, which is a refrigerant-to-coolant heat exchanger. The intermediate heat exchanger 126 can have any suitable design. For example, the intermediate heat exchanger 126 can have a plate fin, tube fin, or shell-and-tube design, which allows the transfer of thermal energy without mixing the heat transfer fluids. The intermediate heat exchanger 126 can be connected to line 72 of the refrigerant subsystem 52 and to line 122 of the passenger compartment loop 54. In some operating modes, the intermediate heat exchanger 126 can transfer thermal energy from the refrigerant subsystem 52 to the passenger compartment loop 54 to heat the passenger compartment 46.In other operating modes, the intermediate heat exchanger 126 can transfer thermal energy from the refrigerant subsystem 52 to the passenger compartment loop 54 to heat the engine 14. In yet another operating mode, during air conditioning mode, the intermediate heat exchanger 126 can act as a condenser and transfer heat from the refrigerant subsystem 52 to the passenger compartment loop 54. The passenger compartment loop 54 can include a bypass line (not shown) to bypass the intermediate heat exchanger 126 when heat exchange between the passenger compartment loop 54 and the refrigerant subsystem 52 is undesirable. The bypass line can be controlled by a valve.

[0025] Refrigerant system 50 can operate in several different modes, which can be divided into two main categories: heating and air conditioning. Refrigerant system 50 can operate in several different air conditioning modes, including a primary and a secondary air conditioning mode. Refrigerant subsystem 52 operates differently in the primary and secondary air conditioning modes.

[0026] In the first air conditioning mode, the external heat exchanger 66 acts as a condenser, and the internal heat exchanger acts as an evaporator 68, which is typical for automotive refrigerant systems. In this mode, the compressor 64 compresses the refrigerant into hot vapor, which is passed through an inactive intermediate heat exchanger 126 to the expansion device 84, which is in the fully open position. As the refrigerant flows through the heat exchanger 66, it condenses into a liquid state because heat is transferred from the refrigerant to the air flowing through the heat exchanger 66. The valve 82 is in the closed position, forcing the refrigerant to flow from the heat exchanger 66 through the line 76 to the second expansion device 86. The expansion device 86 is in the throttled position. The expansion device 86 reduces the pressure and temperature of the refrigerant before it enters the evaporator 68.The evaporator 68 extracts heat from the air circulating within the HVAC housing 58 to cool the passenger compartment 46. The refrigerant then leaves the evaporator 68 and flows through the pressure accumulator 70 for recirculation and back to the compressor 64. In this mode, the bypass valve 90 is in the closed position, forcing all the refrigerant to flow through the heat exchanger 66 according to the invention. In this mode, the auxiliary pump 114 can be switched off and the valve 116 can be positioned so that no refrigerant flows through the intermediate heat exchanger 126, thus preventing heat transfer from the passenger compartment loop 54 to the refrigerant subsystem 52.

[0027] Fig. Figure 4 shows vehicle 10 operating in the second climate control mode. The bold lines indicate active lines. If the engine coolant temperature falls below a threshold temperature (Temp THIf the battery state of charge (SOC) is below a certain threshold, the refrigerant system 50 can operate in the second climate control mode. Plug-in hybrid electric vehicles (PHEVs) typically operate in a charge depletion mode when first starting with a high battery SOC. The vehicle continues in charge depletion mode until the battery SOC drops below a threshold state of charge, at which point the vehicle enters a charge maintenance mode. During charge depletion mode, the engine 14 operates intermittently, if at all. Therefore, the refrigerant temperature typically remains below the threshold temperature until the vehicle switches to charge maintenance mode. The second climate control mode is typically available when the vehicle is in charge depletion mode.

[0028] In this mode, the intermediate heat exchanger 126 is the condenser, the heat exchanger is the evaporator 68, and the external heat exchanger 66 is inactive. The intermediate heat exchanger 126 transfers thermal energy from the refrigerant to the coolant, rather than to the outside air as in a traditional automotive condenser. For this reason, no airflow is required within the engine compartment 48. Therefore, the grille flaps 40 can be closed, and the engine fan 152 can be switched off. Closing the grille flaps 40 increases the vehicle's aerodynamics, thus improving fuel efficiency and electric range. Switching off the engine fan 152 reduces the current draw of the traction battery 20 and increases battery range. This combination of improved aerodynamics and reduced current draw contributes to increasing the vehicle's electric range 10.Furthermore, this preheats the engine and other components, increasing efficiency during engine start-up and thus improving fuel economy.

[0029] In the second air conditioning mode, the compressor 64 compresses the refrigerant into a hot vapor, which is passed through an active intermediate heat exchanger 126 acting as a condenser. The expansion device 84 is closed, and the bypass valve 90 is open, allowing the refrigerant to circulate through the bypass loop 88, bypassing the external heat exchanger 66. The refrigerant is then routed through line 76 to the evaporator 68. The refrigerant flowing through the evaporator 68 evaporates and extracts heat from the air circulating within the HVAC housing 58 to cool the passenger compartment. The refrigerant is then returned to the compressor 64 via line 78.

[0030] Valve 116 is actuated so that the passenger compartment loop 54 and the engine cooling loop 130 form a single coolant circuit. The coolant within the passenger compartment loop 54 and the engine cooling loop 130 is circulated through the intermediate heat exchanger 126 to extract heat from the refrigerant subsystem 52 and condense the refrigerant. One or both of pumps 114 and 136 can be switched on to circulate the coolant. For example, both the auxiliary pump 114 and the engine coolant pump 136 are switched on to circulate coolant through the intermediate heat exchanger 126 and via line 122 to the heater core 110. In some embodiments, a heater core bypass line may be provided. From the heater core 110, coolant is routed via line 124 to valve 116. Valve 116 is actuated to allow coolant to circulate from line 124 via line 150 to the thermostat.The coolant then circulates via line 146 to the engine coolant pump 136. The engine coolant pump 136 directs the coolant through water jackets within the engine 14 and through an engine outlet channel to line 140. Line 140 contains a fitting configured to direct a portion of the coolant to line 142 and a portion to line 128 of the passenger compartment loop 54. A much larger portion of the coolant can be directed to line 128 than to line 142. The portion directed to line 128 is routed back to the auxiliary pump 114. Line 142 is connected to the radiator 132 and to the radiator bypass 148. In some embodiments, the radiator bypass 148 is instead connected to line 140. Thermostat 134 is closed because the opening temperature for the thermostat is higher than or equal to the threshold temperature.The threshold temperature can be between 25 and 50 degrees Celsius (°C). Because the thermostat 134 is closed, the radiator 132 is inactive, and any coolant in line 142 is routed through the radiator bypass 148 and back to the engine coolant pump 136.

[0031] Unlike traditional air conditioning operation, which uses airflow as the condensation medium, the engine coolant is used as the condensation medium during the second air conditioning mode. The engine 14 is a large heat sink capable of absorbing a significant amount of thermal energy. Depending on the size and materials of the engine 14, the coolant loop can be used as the condensation medium for a reasonable amount of time before the coolant temperature exceeds the threshold temperature. When the coolant temperature exceeds the threshold temperature, the air conditioning control system must switch to the first air conditioning mode because the coolant temperature is too high to properly condense the refrigerant in the refrigerant subsystem 52, thus reducing the efficiency and capacity of the refrigerant subsystem.

[0032] Fig. 5 represents a control strategy 200 for selecting between the first and second air conditioning operating modes. In operation 202, the controller determines whether air conditioning is requested. If no, the controller returns to the beginning. If yes, the controller proceeds to operation 204 and determines whether the refrigerant temperature is less than or equal to the threshold temperature. If the refrigerant temperature is above the threshold temperature, the controller proceeds to operation 206, and the air conditioning control system operates in the first air conditioning mode. If the refrigerant temperature is less than or equal to the threshold temperature, the refrigerant system 50 can operate in the second air conditioning mode. In operation 208, the controller instructs the expansion device 84 to assume the closed position and the bypass valve 90 to assume the open position.When the expansion device 84 and the valve are actuated in this manner, the refrigerant bypasses the external heat exchanger 66 and flows from line 72 via the bypass loop 88 to line 76. In operation 210, the controller sends a signal to activate the engine coolant pump 136, the auxiliary pump 114, or both pumps to circulate coolant through the intermediate heat exchanger 126. In operation 212, the controller sends a signal to activate the passenger compartment blower 60 to direct cool air into the passenger compartment 46. In operation 214, the controller sends a signal to actuate the valve 116, directing coolant from the heater core to the engine 14. In operation 216, the controller sends a signal instructing the grille flaps 40 to assume the closed position to improve the vehicle's aerodynamics. During operation 218, the controller sends a signal to switch off the motor fan 152.

[0033] Fig. Figure 6 represents a control strategy 250 for switching from the second climate control mode to the first climate control mode. In operation 252, the controller determines whether climate control is requested. If climate control is requested, the controller proceeds to operation 254 and determines whether the coolant temperature is higher than the threshold temperature. If not, the vehicle continues to operate in the second climate control mode. If yes, the controller proceeds to operation 258 and sends a signal instructing the expansion device 84 to assume a wide-open position and the bypass valve 90 to assume a closed position to direct the refrigerant to the external heat exchanger 66. In operation 260, the controller sends a signal to switch off the auxiliary pump 114 and close the valve 116 to stop the circulation of coolant through the intermediate heat exchanger 126.In operation 262, the control determines a position of the grill closure flap 40, and in operation 264 it determines a utilization level of the motor fan 152.

[0034] Fig. Operation 300 represents another control strategy for selecting between the first and second air conditioning operating modes. In Operation 302, the controller determines whether air conditioning is requested. If no, the controller returns to the beginning. If yes, the controller proceeds to Operation 304 and determines whether the refrigerant temperature is less than or equal to the threshold temperature. If the refrigerant temperature is above the threshold temperature, the controller proceeds to Operation 306, and the refrigerant system 50 operates in the first air conditioning mode. If the refrigerant temperature is less than or equal to the threshold temperature, the controller proceeds to Operation 308. In Operation 308, the controller determines whether the battery state of charge (SOC) is greater than or equal to a threshold charge. THIf no, the controller proceeds to operation 306, and the system operates in the first air conditioning mode. If yes, the controller proceeds to operation 310 and determines whether the vehicle is in a charge exhaustion mode. If the vehicle is not operating in a charge exhaustion mode, the controller proceeds to operation 306. If the vehicle is in a charge exhaustion mode, the refrigerant system 50 can operate in the second air conditioning mode, and the controller proceeds to operation 312. In operation 312, the controller instructs the expansion device 84 to assume the closed position and the bypass valve 90 to assume the open position. When the expansion device 84 and the valve are actuated in this manner, the refrigerant bypasses the external heat exchanger 66 and flows from line 72 through the bypass loop 88 to line 76.In operation 314, the control unit switches on the engine coolant pump 136, the auxiliary pump 114, or both pumps to circulate coolant through the intermediate heat exchanger 126. In operation 316, the control unit sends a signal to switch on the passenger compartment blower 60 to direct cool air into the passenger compartment 46. In operation 318, the valve 116 is actuated so that coolant is directed from the heater core 110 to the engine 14. In operation 320, the control unit sends a signal instructing the grille flaps 40 to assume the closed position to improve the vehicle's aerodynamics. In operation 322, the control unit sends a signal to switch off the engine fan 152. The control strategies were developed with reference to the [document / reference] in the [document / reference]. Fig. 3 and Fig. The vehicle layout shown in section 4 is described. However, the control strategies are also applicable to other layouts.

[0035] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the description serve to describe, not to limit, and it is understood that various modifications can be made without departing from the intent and scope of the disclosure. As previously described, the features of different embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated.While various embodiments may have been described as offering advantages or being preferable to other embodiments or implementations of the prior art with respect to one or more desired properties, the average person skilled in the art understands that compromises are made between one or more features or properties in order to achieve desired characteristics of the overall system, which depend on the specific application and implementation. These characteristics may include, among others, cost, strength, durability, life-cycle costs, marketability, appearance, space utilization, size, ease of maintenance, weight, manufacturability, ease of assembly, etc.Embodiments that are described as less desirable than other embodiments or implementations corresponding to the prior art with respect to one or more properties are therefore not outside the scope of protection of the disclosure and may be desirable for certain applications.

[0036] It is further described as follows: A. Vehicle, including: an engine; a traction battery that is electrically connected to at least one electric machine; a refrigerant system comprising an external heat exchanger, an intermediate heat exchanger, an expansion device located between the heat exchangers, and a bypass loop having an inlet arranged between the heat exchangers and configured to bypass the external heat exchanger; a coolant circuit containing a pump designed to circulate coolant through the engine and the intermediate heat exchanger; grille flaps located behind a front panel of the vehicle and in front of the external heat exchanger; and A control system programmed to close the expansion device in response to a request for air conditioning and when the refrigerant temperature is below a threshold temperature, allowing the refrigerant to bypass the external heat exchanger via the bypass loop, and to turn on the pump to transfer heat from the refrigerant system to the coolant circuit via the intermediate heat exchanger, causing refrigerant to condense in the intermediate heat exchanger. B. Vehicle to A, wherein the control unit is further programmed to request the closing of the grille flaps. C. Vehicle according to A, wherein the control is further programmed to perform the closing and switching on in response to a battery charge level higher than a threshold charge. D. Vehicle according to C, wherein the control is further programmed to perform the closing and switching on in response to the fact that the vehicle is in a charge exhaustion mode. E. Vehicle to A, wherein the control is further programmed to perform the closing and switching on in response to the fact that the battery is in a charge depletion mode. F. Vehicle according to A, which further comprises a fan arranged behind the grille flaps, wherein the control is further programmed to delay the switching on of the fan at least until the temperature exceeds the threshold temperature. G. Vehicle according to A, wherein the coolant circuit further includes a valve, and wherein the control is further programmed to open the expansion device, switch off the pump and close the valve in order to condense refrigerant in the external heat exchanger in response to the temperature exceeding the threshold temperature. H. Vehicle to G, wherein the control is further programmed to open the grille closure flaps. I. Vehicle, comprising: a refrigerant system comprising an intermediate heat exchanger, an external heat exchanger and an expansion device arranged between them; a coolant circuit that includes a pump designed to circulate coolant through the intermediate heat exchanger and a power unit; and a control system programmed to open the expansion device and shut off the pump to condense refrigerant in the external heat exchanger in response to a request for air conditioning and when the refrigerant temperature exceeds a threshold temperature. J. Vehicle according to I, which further comprises grille closure flaps arranged behind a front panel of the vehicle and includes an actuator designed to change the position of the grille closure flaps, wherein the control is further programmed to send a signal to the actuator instructing the grille closure flaps to assume an open position. K. Vehicle according to I, which further comprises a fan adjacent to the external heat exchanger, wherein the control is further programmed to switch on the fan. L. Vehicle according to I, wherein the refrigerant system further comprises a compressor, a bypass loop with an inlet arranged between the compressor and the external heat exchangers, an outlet connected to a line arranged downstream of the external heat exchanger, and a valve that can be actuated to circulate refrigerant around the external heat exchanger, wherein the control is further programmed to close the valve. M. Vehicle according to I, which further comprises a traction battery electrically connected to at least one electric machine designed to deliver torque selectively to the driven wheels of the vehicle. N. Method for operating a climate control system of a vehicle comprising grille shutter flaps and a heat exchanger in fluid communication with a refrigerant system and an engine cooling loop comprising coolant, wherein the method comprises: Transfer of heat from the refrigerant system via the heat exchanger to the engine cooling loop and the closing of the grille flaps in response to this, that air conditioning is requested and the refrigerant has a temperature below a threshold temperature. O. Method according to N, which further includes the condensation of refrigerant in the heat exchanger. P. Method according to N, wherein the climate control system further includes a fan arranged behind the grille flaps and the method further includes delaying the activation of the fan, at least until the temperature exceeds the threshold temperature. Q. Method according to N, wherein the climate control system further comprises an external heat exchanger arranged behind the grille closure flaps and an expansion device arranged on a line extending between the heat exchanger and the external heat exchanger, and wherein the method further comprises closing the expansion device. R. Method according to Q, which further comprises opening the expansion device in response to the temperature exceeding the threshold temperature. S. Method according to R, which further includes the condensation of refrigerant in the external heat exchanger.

Claims

[1] Vehicle (10), comprising: a refrigerant system (50) comprising an intermediate heat exchanger (126), an external heat exchanger (66) and an intermediate expansion device (84) as well as a bypass loop (88) for bypassing the external heat exchanger (66); a coolant circuit comprising an auxiliary pump (114) designed to circulate coolant through the intermediate heat exchanger (126) and a power unit (14); and a control unit (100) which is programmed to open the expansion device (84) and switch off the auxiliary pump (114) and to close a bypass valve (90) so that all the refrigerant flows through the external heat exchanger (66) to condense refrigerant in the external heat exchanger (66) in response to a request for air conditioning and when the refrigerant temperature exceeds a threshold temperature. [2] Vehicle (10) according to claim 1, further comprising grille closure flaps (40) arranged behind a front panel (41) of the vehicle (10) and an actuator (44) designed to change the position of the grille closure flaps (40), wherein the control (100) is further programmed to send a signal to the actuator (44) instructing the grille closure flaps (40) to assume an open position. [3] Vehicle (10) according to claim 1, further comprising a motor fan (152) adjacent to the external heat exchanger (66), wherein the control unit (100) is further programmed to switch on the motor fan (152). [4] Vehicle (10) according to claim 1, wherein the refrigerant system (50) further comprises a compressor (64), the bypass loop (88) with an inlet arranged between the compressor (64) and the external heat exchanger (66), an outlet connected to a line (76) arranged downstream of the external heat exchanger (66), and the bypass valve (90) which is actuated to allow refrigerant to circulate around the external heat exchanger (66). [5] Vehicle (10) according to claim 1, further comprising a traction battery (20) electrically connected to at least one electric machine (18) designed to deliver torque selectively to the driven wheels (22) of the vehicle.

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