Patent Application
20230147794
The subject disclosure relates to electric vehicles, and more precisely to heating of a cabin and a rechargeable energy storage system (RESS) of an electric vehicle.
A typical RESS, also known by the term a “battery pack” or other similar nomenclature has an optimal performance within a narrow temperature range. When operating conditions fall outside of this range at an upper end, the RESS is cooled by circulating a flow of coolant therethrough. When, on the other hand, the operating temperature is low, it is desired to heat RESS to maintain performance. This heating is typically achieved via a separate cooling heater connected to the system.
In one embodiment, a heating, ventilation and air conditioning (HVAC) system for a vehicle having a rechargeable energy storage system includes a refrigerant circuit having a flow of refrigerant circulated therethrough. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. A coolant circuit is fluidly connected to the refrigerant circuit and has a flow of coolant circulated therethrough. The coolant circuit includes the chiller heat exchanger, the internal condenser, a heater core, a rechargeable energy storage system (RESS), and a three-way coolant valve to selectably direct the flow of coolant through the RESS and/or along a bypass passage to bypass the RESS.
Additionally or alternatively, in this or other embodiments the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser.
Additionally or alternatively, in this or other embodiments in a heat pump mode, the flow of refrigerant is directed through an outside heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments an outside heat exchanger expansion valve is operable to selectably direct the flow of refrigerant through the outside heat exchanger.
Additionally or alternatively, in this or other embodiments the heat pump mode is utilized when an ambient temperature is greater than −10 degrees Celsius.
Additionally or alternatively, in this or other embodiments the three-way coolant valve is located along the coolant circuit between the heater core and the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments the bypass passage extends from the three-way coolant valve to a location of the coolant circuit between the RESS and the internal condenser.
Additionally or alternatively, in this or other embodiments in a RESS heating mode, the flow of refrigerant is directed through the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments the RESS heating mode is utilized when an ambient air temperature is less than −10 degrees Celsius.
Additionally or alternatively, in this or other embodiments a pump circulates the flow of coolant through the coolant circuit.
Additionally or alternatively, in this or other embodiments the pump is located in the coolant circuit fluidly upstream of the internal condenser and the heater core, and fluidly downstream of the RESS.
In another embodiment, a method of heating a rechargeable energy storage system of a vehicle includes circulating a flow of refrigerant through a refrigerant circuit. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. A flow of coolant is circulated through a coolant circuit. The coolant circuit includes the internal condenser, a heater core, and a rechargeable energy storage system (RESS). The flow of refrigerant is heated via operation of the compressor. The flow of coolant is selectably directed to one or more of the RESS and a bypass passage to bypass the RESS via a three-way coolant valve. One or more of the RESS and the heater core are heated via the flow of coolant.
Additionally or alternatively, in this or other embodiments the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser.
Additionally or alternatively, in this or other embodiments in a heat pump mode, the flow of refrigerant is directed through an outside heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments the heat pump mode is utilized when an ambient temperature is greater than −10 degrees Celsius.
Additionally or alternatively, in this or other embodiments the three-way coolant valve is located along the coolant circuit between the heater core and the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments the bypass passage extends from the three-way coolant valve to a location of the coolant circuit between the RESS and the internal condenser.
Additionally or alternatively, in this or other embodiments in a RESS heating mode, the flow of refrigerant is directed through the chiller heat exchanger.
Additionally or alternatively, in this or other embodiments the RESS heating mode is utilized when an ambient air temperature is less than −10 degrees Celsius.
Additionally or alternatively, in this or other embodiments the flow of coolant is circulated through the coolant circuit via a pump, the pump located in the coolant circuit fluidly upstream of the internal condenser and the heater core, and fluidly downstream of the RESS.
The above features and advantages, and other features and advantages of the disclosure are readily apparent from the following detailed description when taken in connection with the accompanying drawings.
Other features, advantages and details appear, by way of example only, in the following detailed description, the detailed description referring to the drawings in which:
The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
In accordance with an exemplary embodiment, an illustration of a heating, ventilation, and air conditioning (HVAC) system 10 for a vehicle is shown in
In the internal condenser 20, the flow of coolant of the coolant circuit 16 exchanges thermal energy with a flow of refrigerant from the refrigerant circuit 22. The refrigerant circuit 22 further includes a compressor 24 disposed fluidly upstream of the internal condenser 20, and three heat exchangers arranged in a fluidly parallel relationship downstream of the internal condenser 20. The three heat exchangers include an outside heat exchanger 26, an evaporator 28 and a chiller heat exchanger 30. Each heat exchanger has an associated expansion device located fluidly between the internal condenser 20 and the respective heat exchanger. The expansion devices are, respectively, an outside expansion valve 32, an evaporator expansion valve 34 and a chiller expansion valve 36. The chiller heat exchanger 30 is further connected to the coolant circuit 16 for thermal energy exchange between the flow of coolant and the flow of refrigerant at the chiller heat exchanger 30.
A RESS valve 42 is used to connect the coolant circuit 16 and a power electronics coolant loop 44, thereby exchanging heat between the two coolant loops on an as needed basis. In some embodiments, a coolant heater 46 can be placed between the RESS valve 42 and the pump 18 to provide additional heating to the RESS 12 and cabin on an as needed basis. Alternatively, the coolant heater 46 can be placed between chiller heat exchanger 30 and the RESS 12.
The HVAC system 10 is configured to operate in several operating modes, depending on the thermal demands of the RESS 12 and the heater core 14, and on ambient conditions and operating conditions of the vehicle, as will be discussed in greater detail below. To facilitate switching of operating modes, the HVAC system 10 includes a plurality of valves to selectably direct the flow of coolant and the flow of refrigerant along selected fluid pathways in the coolant circuit 16 and the refrigerant circuit 22. The coolant circuit 16 includes a three-way coolant valve 38 to selectably direct the flow of coolant through the chiller heat exchanger 30 and/or through a bypass passage 40 to a location between the pump 18 and the RESS 12, thus bypassing the RESS 12 and the chiller heat exchanger 30. In addition to the aforementioned expansion valves, the refrigerant circuit 22 includes an outside heat exchanger valve 52 and an internal condenser refrigerant valve 54 to selectably direct the flow of refrigerant from the compressor 24 through the outside heat exchanger 26 or through the internal condenser 20.
A first operating mode, or heat pump mode, of the HVAC system 10 is illustrated in
Referring now to
In the coolant loop 16, thermal energy is exchanged between the flow of coolant and the flow of refrigerant at the internal condenser 20. The heated flow of coolant then flows through the heater core 14 and is selectably directed through the three-way coolant valve 38 to the RESS 12 and/or through the bypass passage 40, depending on the heating needs of the RESS 12. When heating of both the cabin and the RESS 12 are required, RESS 12 heating will be limited, otherwise the RESS 12 will act as a heat sink and pull in all of the flow of coolant to the RESS 12.
The use of the three-way coolant valve 38 allows modulation of the flow of coolant through the chiller heat exchanger 30 and the RESS 12, such that the RESS 12 may be heated by the flow of coolant that is waste heat not utilized by the heater core 14 for cabin heating.
While the above disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from its scope. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within the scope thereof.
