Thermal management system for a vehicle and methods for operating a thermal management system

Abstract

Thermal management system (10) for a vehicle, wherein the thermal management system (10) comprises: several fluid flow circuits that include: a heating, ventilation and air conditioning circuit (HVAC circuit) through which a refrigerant flow circulates, wherein the HVAC circuit contains: an evaporator (40); a cooler heat exchanger (42) arranged parallel to the evaporator (40); a first expansion valve (44) which is arranged upstream of the evaporator (40); a second expansion valve (46) arranged upstream of the radiator heat exchanger (42); and a heat exchanger (64) which is arranged fluidically upstream of the first expansion valve (44) and the second expansion valve (46); and a drive conditioning circuit (18) through which a coolant flow circulates, wherein the coolant flow is used to condition one or more drive components of the vehicle, wherein the coolant flow is passed through the heat exchanger (64) to exchange thermal energy with the refrigerant flow, thereby subcooling the refrigerant flow; and a controller (66) which is operationally connected to one or more control points of the thermal management system (10), wherein the controller (66) is configured to set the one or more control points in order to achieve a target amount of subcooling of the refrigerant flow at the heat exchanger (64).

Description

INTRODUCTION

[0001] The present invention relates to a thermal management system for a vehicle and to a method for operating a thermal management system.

[0002] For general background information, reference should be made in advance to DE 10 2019 129 304 A1.

[0003] While conventional thermal management systems and methods are well-established in vehicles with internal combustion engines and can be partially applied to innovative propulsion systems such as battery electric vehicles (BEVs), hybrid electric vehicles, or fuel cell vehicles, the amount of available excess thermal energy is much lower than in an internal combustion engine system. Consequently, there is a need for improved thermal management systems and methods that efficiently collect, store, and distribute thermal energy to vehicle systems. SUMMARY

[0004] According to the invention, a thermal management system for a vehicle is presented, characterized by the features of claim 1.

[0005] The thermal management system for a vehicle comprises several fluid flow circuits, including a heating, ventilation, and air conditioning (HVAC) circuit through which a refrigerant flow circulates. The HVAC circuit contains an evaporator, a radiator heat exchanger arranged parallel to the evaporator, a first expansion valve located upstream of the evaporator, a second expansion valve located upstream of the radiator heat exchanger, and a heat exchanger located fluidically upstream of both the first and second expansion valves. A coolant flow circulates through a drivetrain cooling circuit. This coolant flow is used to condition one or more drivetrain components of the vehicle.The coolant flow is directed through the heat exchanger to exchange thermal energy with a refrigerant flow, thereby subcooling the refrigerant flow. A controller is operationally connected to one or more control points of the thermal management system. The controller is configured to adjust the one or more control points to achieve a target amount of subcooling of the refrigerant flow at the heat exchanger.

[0006] Additionally or alternatively, according to this or other embodiments, one or more control points include a coolant heating device of the drive cooling circuit, a drive conditioning circuit pump, or a compressor of the HVAC circuit.

[0007] Additionally or alternatively, according to this or other embodiments, one or more drive system components include a rechargeable energy storage system.

[0008] Additionally or alternatively, according to this or other embodiments, a drive coolant flow circulates through a drive unit cooling circuit to provide cooling for one or more drive units of the vehicle. The drive unit cooling circuit is operationally connected to the drive cooling circuit via a drive unit cooling circuit heat exchanger.

[0009] Additionally or alternatively, according to this or other embodiments, a drive unit cooling circuit pump drives the drive coolant flow along the drive unit cooling circuit.

[0010] Additionally or alternatively, according to this or other embodiments, one or more control points include the drive unit cooling circuit pump.

[0011] Additionally or alternatively, according to this or other embodiments, a low-temperature cooler is located along the drive unit cooling circuit.

[0012] Additionally or alternatively, according to this or other embodiments, one or more control points include a flow rate of the drive coolant through the low-temperature cooler.

[0013] Furthermore, according to the invention, a method for operating a thermal management system is presented, which is characterized by the features of claim 7.

[0014] The process involves providing multiple fluid flow circuits, including a heating, ventilation, and air conditioning (HVAC) circuit through which a refrigerant flow circulates, and a drive cooling circuit through which a coolant flow circulates. The drive cooling circuit is fluidically connected to the HVAC circuit via a heat exchanger. The degree of subcooling of the refrigerant flow to be provided to one or more expansion valves located downstream of the heat exchanger is selected. A target coolant temperature and a target coolant flow rate into the heat exchanger to achieve the selected degree of subcooling are determined. One or more control points of the thermal management system are set to achieve the target coolant temperature and target coolant flow rate.

[0015] Additionally or alternatively, according to this or other embodiments, the target refrigerant temperature is selected using a saturation temperature of the refrigerant flow and a load of the HVAC circuit.

[0016] Additionally or alternatively, according to this or other embodiments, the target refrigerant flow rate is selected using the saturation temperature of the refrigerant flow, the load of the HVAC circuit and a temperature of the refrigerant flow.

[0017] Additionally or alternatively, according to this or other embodiments, the target coolant temperature or the target coolant flow rate is set based on the amount of heat dissipated in the coolant flow at a cooler of the thermal management system, which is located fluidically upstream of the heat exchanger.

[0018] Additionally or alternatively, according to this or other embodiments, one or more control points include a coolant heating device of the drive conditioning circuit, a drive conditioning circuit pump, or a compressor of the HVAC circuit.

[0019] Additionally or alternatively, according to this or other embodiments, the coolant flow is used to condition one or more drive components of a vehicle.

[0020] Additionally or alternatively, the thermal management system, according to this or other embodiments, includes a powertrain cooling circuit through which a flow of powertrain coolant circulates to provide cooling for one or more powertrains of the vehicle. The powertrain cooling circuit is operationally connected to the powertrain cooling circuit via a powertrain cooling circuit heat exchanger.

[0021] Additionally or alternatively, according to this or other embodiments, the drive coolant flow is driven via a drive unit cooling circuit pump along the drive unit cooling circuit.

[0022] Additionally or alternatively, according to this or other embodiments, one or more control points include the drive unit cooling circuit pump.

[0023] Additionally or alternatively, according to this or other embodiments, a low-temperature cooler is located along the drive unit cooling circuit.

[0024] Additionally or alternatively, according to this or other embodiments, one or more control points include a flow rate of the drive coolant through the low-temperature cooler.

[0025] According to a further embodiment, a non-transient, computer-readable medium contains instructions to cause a controller to execute a method for operating a thermal management system. The method includes providing several fluid flow circuits, including a heating, ventilation, and air conditioning (HVAC) circuit through which a refrigerant flow circulates, and a drive cooling circuit through which a coolant flow circulates, the drive cooling circuit being fluidically connected to the HVAC circuit via a heat exchanger.An amount of subcooling of the refrigerant flow to be provided to one or more expansion valves located fluidically downstream of the heat exchanger is selected, a target refrigerant temperature and target refrigerant flow rate into the heat exchanger are selected to achieve the selected amount of subcooling, and one or more control points of the thermal management system are set to achieve the target refrigerant temperature and target refrigerant flow rate.

[0026] The above features and advantages and other features and advantages of the invention are easily apparent from the following detailed description when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further features, advantages and details appear in the following detailed description only as examples, the detailed description referring to the drawings; they show: Fig. 1. A schematic illustration of an embodiment of a thermal management system for a vehicle; and Fig. 2 a schematic illustration of an exemplary procedure for operating a thermal management system for a vehicle. DETAILED DESCRIPTION

[0028] The following description is merely exemplary. It should be recognized that throughout the drawings, corresponding reference symbols indicate the same or corresponding parts and features.

[0029] According to an exemplary embodiment, in Fig. Figure 1 shows a schematic illustration of a thermal management system 10 for a vehicle. The thermal management system 10 contains several interconnected fluid flow circuits to manage the thermal energy requirements of the various vehicle systems and components. A first fluid flow circuit is a heating, ventilation, and air conditioning (HVAC) circuit. The HVAC circuit circulates a refrigerant flow along a refrigerant path 14 and uses the refrigerant flow to, for example, climate control a vehicle cabin 16 by providing either a heating or cooling airflow to the cabin 16. A second fluid flow circuit is a powertrain conditioning circuit 18. The powertrain conditioning circuit 18 circulates a coolant flow along a powertrain conditioning path 20 and uses the coolant flow to cool powertrain components, e.g.,to maintain a rechargeable energy storage system (RESS) 22, a fuel cell, or the like, at a set operating temperature. The RESS 22 may be one or more rechargeable electric traction batteries, electric double-layer capacitors, or a flywheel energy storage device. A person skilled in the art will readily recognize that the discussion of the use of the RESS 22 in the present application is merely exemplary and that other drive system components may be used in the drive conditioning circuit 18. A third fluid flow circuit is the drive unit cooling circuit 24, which circulates a flow of drive unit coolant along a drive cooling path 26.The flow of the drive unit coolant is used to cool one or more drive units 28 of the vehicle, which, according to some embodiments, are operationally connected to the RESS 22 and can be driven using energy from the RESS 22. Each fluid flow circuit is described in more detail below.

[0030] The HVAC circuit includes a compressor 30, which compresses and drives the refrigerant flow along the refrigerant path 14. The HVAC circuit includes a front condenser 32 and a heating condenser 34, which are arranged in parallel, with the refrigerant flow selectively flowing through either the front condenser 32 and / or the heating condenser 34 by actuating the respective front condenser valve 36 and the heating condenser valve 38. From the heating condenser 34 and the front condenser 32, the refrigerant flow is directed towards an evaporator 40 and one or more coolers 42, which are arranged fluidically parallel to the evaporator 40. A first expansion valve 44 and a second expansion valve 46 are located fluidically upstream of the evaporator 40 and the cooler 42, respectively. The refrigerant flow is returned from the evaporator 40 and the cooler 42 to the compressor 30.

[0031] The drive unit cooling circuit 24 circulates the drive coolant flow along the drive cooling path 26, driven by a drive unit cooling circuit pump 48. From the drive unit cooling circuit pump 48, the drive coolant flows through the drive units 28 to provide them with cooling. According to such embodiments, as illustrated, the vehicle contains two drive units 28, while according to other embodiments, other numbers of drive units 28 may be arranged along the drive unit cooling circuit 24 and / or more than one drive unit cooling circuit 24 may be used to cool the drive units 28. As shown in Fig. As illustrated in Figure 1, the drive units 28 are arranged in parallel within the drive unit cooling circuit 24, whereas in other embodiments, the drive units 28 can be arranged in series. An on-board charging module (OBCM) 50 is located between the drive unit cooling circuit pump 48 and the drive units 28, so that the drive coolant flow absorbs thermal energy from the OBCM 50 and the drive units 28. The drive coolant flow is optionally returned to the drive unit cooling circuit pump 48 via a low-temperature cooler 52 and a drive unit cooling circuit heat exchanger 54. In some embodiments, excess drive coolant is directed to an expansion tank 56 until it is required by the drive unit cooling circuit 24.A check valve 58 can be arranged between the low-temperature cooler 52 and the expansion tank 56 to control the flow of drive coolant into the expansion tank 56.

[0032] The drive conditioning circuit 18 is thermally connected to both the HVAC circuit and the drive unit cooling circuit 24. The coolant flow is driven by a drive conditioning circuit pump 60 along the drive conditioning path 20. The coolant flow then proceeds to a coolant heater 62, which, when activated, heats the coolant flow. From the coolant heater 62, the coolant flow continues to the cooler 42, where it exchanges thermal energy with the refrigerant flow in the HVAC circuit, heating the refrigerant and cooling the coolant. From the cooler 42, the coolant flow proceeds to a heat exchanger 64, e.g.a coaxial tube heat exchanger, which is positioned fluidically downstream of the cooler 42 along the drive conditioning circuit 18 and fluidically upstream of the first expansion valve 44 and the second expansion valve 46 in the HVAC circuit. At the heat exchanger 64, the cooled coolant flow discharged from the cooler 42 exchanges thermal energy with the refrigerant flow to subcool the refrigerant flow before the refrigerant flow reaches the first expansion valve 44 and the second expansion valve 46. The coolant flow then proceeds to the RESS 22 to thermally condition the RESS 22 and then continues through the drive unit cooling circuit heat exchanger 54 to exchange thermal energy with the drive coolant flow before returning to the drive conditioning circuit pump 60. According to some embodiments, the coolant flow can be used to cool other components, such asto cool a charging port 68 of the vehicle. A controller 66 is operationally connected to one or more control points of the thermal management system 10 in order to control its operation.

[0033] In Fig.2. A method is used to operate the thermal management system 10 to provide a desired amount of subcooling of the refrigerant flow entering the first expansion valve 44 and the second expansion valve 46. This is achieved by monitoring and modifying parameters such as the flow rate and temperature of the refrigerant flow entering the heat exchanger 64. In block 100, a target subcooling temperature of the refrigerant is determined, from which a target refrigerant temperature and a target refrigerant flow rate are selected in block 102. The target refrigerant temperature can be selected, for example, using the saturation temperature of the refrigerant flow and the load of the HVAC circuit. Similarly, the target refrigerant flow rate can be selected using the saturation temperature of the refrigerant flow, the load of the HVAC circuit, and a temperature of the refrigerant flow.In block 104, a set coolant target temperature and a set coolant flow rate are determined, taking into account the heat dissipation in the coolant flow occurring at the radiator 42 and / or other heat loads. To achieve the set coolant target temperature and the set coolant flow rate, one or more control points of the thermal management system 10 are set in block 106. These control points include, for example, the speed of the drive conditioning circuit pump 60 to adjust the coolant flow rate, the flow of the drive coolant through the low-temperature radiator 52 and / or into the expansion tank 56, which modifies the drive coolant flow through the drive unit cooling circuit heat exchanger 54. Additionally, the operation of the coolant heater 62 can be modified to adjust the coolant temperature.

[0034] Additionally, as discussed, one or more processes 100-106 may be implemented in hardware, firmware, software, or any combination thereof. Exemplary embodiments may also be implemented as instructions stored on a non-volatile, non-transient, machine-readable medium. These are readable and executable by one or more processors. A machine-readable medium contains any mechanism for storing or transmitting information in a form that can be read by a machine (e.g., a computing device). The machine-readable medium may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the foregoing.More specific examples (a non-exhaustive list) of computer-readable storage media include the following: an electrical connection with one or more wires, a portable computer disk, a hard disk, a read / write memory (RAM), a erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0035] The provision of the heat exchanger 64 and the preconditioning of the coolant flow entering the heat exchanger 64, based on the operating parameters of the HVAC circuit, enables the coolant flow to provide a selected amount of subcooling to the refrigerant flow at the heat exchanger 64 before the refrigerant flow flows to the first expansion valve 44 and the second expansion valve 46.

Claims

[1] Thermal management system (10) for a vehicle, wherein the thermal management system (10) comprises: several fluid flow circuits that include: a heating, ventilation and air conditioning circuit (HVAC circuit) through which a refrigerant flow circulates, wherein the HVAC circuit contains: an evaporator (40); a cooler heat exchanger (42) arranged parallel to the evaporator (40); a first expansion valve (44) which is arranged upstream of the evaporator (40); a second expansion valve (46) arranged upstream of the radiator heat exchanger (42); and a heat exchanger (64) which is arranged fluidically upstream of the first expansion valve (44) and the second expansion valve (46); and a drive conditioning circuit (18) through which a coolant flow circulates, wherein the coolant flow is used to condition one or more drive components of the vehicle, wherein the coolant flow is passed through the heat exchanger (64) to exchange thermal energy with the refrigerant flow, thereby subcooling the refrigerant flow; and a controller (66) which is operationally connected to one or more control points of the thermal management system (10), wherein the controller (66) is configured to set the one or more control points in order to achieve a target amount of subcooling of the refrigerant flow at the heat exchanger (64). [2] Thermal management system (10) according to claim 1, wherein one or more control points include a coolant heating device (62) of the drive conditioning circuit (18), a drive conditioning circuit pump (60) or a compressor (30) of the HVAC circuit. [3] Thermal management system (10) according to claim 1, wherein one or more drive system components include a rechargeable energy storage system (22). [4] Thermal management system (10) according to claim 1, which further comprises a drive unit cooling circuit (24) through which a drive coolant flow circulates to provide cooling to one or more drive units (28) of the vehicle, wherein the drive unit cooling circuit (24) is operationally connected to the drive conditioning circuit (18) via a drive unit cooling circuit heat exchanger (54). [5] Thermal management system (10) according to claim 4, further comprising a low-temperature cooler (52) arranged along the drive unit cooling circuit (24). [6] Thermal management system (10) according to claim 5, wherein one or more control points contain a flow rate of the drive coolant through the low temperature cooler (52). [7] Method for operating a thermal management system (10) wherein the method includes: Providing multiple fluid flow circuits that include: a heating, ventilation and air conditioning circuit (HVAC circuit) through which a refrigerant flow circulates; and a drive conditioning circuit (18) through which a coolant flow circulates, wherein the drive conditioning circuit (18) is fluidically connected to the HVAC circuit via a heat exchanger (64); Selecting an amount of subcooling of the refrigerant flow that is provided to one or more expansion valves (44, 46) which are arranged fluidically downstream of the heat exchanger (64); Determining a target coolant temperature and a target coolant flow rate into the heat exchanger (64) to achieve the selected amount of subcooling; Setting one or more control points of the thermal management system (10) to achieve the target coolant temperature and target coolant flow rate. [8] Method according to claim 7, wherein the target refrigerant temperature is selected using a saturation temperature of the refrigerant flow and a load of the HVAC circuit. [9] Method according to claim 7, wherein the target coolant flow rate is selected using the saturation temperature of the refrigerant flow, the load of the HVAC circuit and a temperature of the coolant flow. [10] Method according to claim 7, further comprising setting the target coolant temperature and / or the target coolant flow rate based on the amount of heat dissipated in the coolant flow at a cooler of the thermal management system (10) which is located fluidically upstream of the heat exchanger (64).

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