ELECTRIC VEHICLE INTERIOR AIR CONDITIONING SYSTEM

Abstract

The passenger compartment air conditioning system (PACS) of an electric vehicle (EV) includes a reversible air-to-air heat pump (HP). According to the invention, the heat pump includes a heat exchange interface (HII) with a thermoregulation device (TRD) of the vehicle's electric traction energy storage (ET). The heat exchange interface includes a heat exchange device (HED) having a refrigerant circulating evaporator circuit (CFC) integrated into a refrigerant loop of the heat pump and a heat transfer fluid circulating exchanger circuit (HFC) integrated into the thermoregulation device of the electric traction energy storage. The HED also includes a controlled means (CM) for establishing a heat transfer fluid heating loop within the thermoregulation device of the electric traction energy storage, which includes the heat transfer fluid circulating exchanger circuit. Figure 1

Description

Title of the invention: AIR CONDITIONING SYSTEM FOR THE PASSENGER COMPARTMENT OF AN ELECTRIC VEHICLE

[0001] The present invention relates generally to the air conditioning of the passenger compartment of an electric vehicle. More particularly, the invention relates to an air conditioning system for the passenger compartment of an electric vehicle.

[0002] In a thermal vehicle, the combustion engine releases a significant amount of calories which are evacuated by the vehicle's cooling circuit. The heating of the vehicle's passenger compartment is provided by an air heater in which the heat transfer fluid from the engine's cooling circuit circulates.

[0003] In an electric vehicle, the electric traction motor has a high energy efficiency and generates only a small amount of heat loss that could be used to heat the passenger compartment. To ensure good thermal comfort in cold weather, the energy available in the vehicle's electric traction storage unit must be used to heat the passenger compartment of the vehicle. The electrical consumption of the passenger compartment heating impacts the range of the electric vehicle.

[0004] The reversible air / air heat pump system, which offers advantageous energy efficiency, has established itself as an interesting solution for air conditioning the passenger compartment of the electric vehicle. However, in very cold weather, with outside temperatures below -20°C, the heat pump system is no longer within its operating range and is ineffective for heating the passenger compartment of the vehicle.

[0005] In the state of the art, in order to compensate for the lack of efficiency of the heat pump system for outside temperatures below -20°C, it is known to add to the latter a resistive electric radiator with a positive temperature coefficient (PTC), called a "PTC heater" in English. The "PTC" resistive radiator is powered by the high direct voltage delivered by the vehicle's electric traction storage unit. This "PTC" resistive radiator, which increases its ohmic value with the temperature, thus self-regulates its heating power by adjusting the electric current passing through it. However, it has a disadvantage which is to significantly impact the cost of the air conditioning system of the passenger compartment of the electric vehicle.

[0006] From document US5967224A, it is known in a vehicle to eliminate an expensive conduit from the cabin heating device when an air conditioner is mounted in the vehicle. From document US20100154445A1, it is known to mount in a vehicle, such as an armored military vehicle, a removable air conditioning unit in place of a cabin heating device, so as to adapt the vehicle to the climatic conditions of a geographical area.

[0007] The present invention aims to provide an air conditioning system for the passenger compartment of an electric vehicle capable of operating with outside temperatures below -20°C, without having to integrate a resistive “PTC” radiator as in the systems of the prior art.

[0008] According to a first aspect, the invention relates to a passenger compartment air conditioning system in an electric vehicle, comprising a reversible air / air heat pump. According to the invention, the heat pump comprises a heat exchange interface with a thermoregulation device of an electric traction storage device of the vehicle, the heat exchange interface comprising a heat exchange device having a refrigerant circulation evaporator circuit integrated in a refrigerant loop of the heat pump and a heat transfer fluid circulation exchanger circuit integrated in the thermoregulation device of the electric traction storage device, and a controlled means for establishing in the thermoregulation device of the electric traction storage device a heat transfer fluid heating loop including the heat transfer fluid circulation exchanger circuit.

[0009] According to a particular characteristic, the controlled means is an electrically controlled three-way valve.

[0010] The invention also relates to an assembly integrated in an electric vehicle comprising a passenger compartment air conditioning system as briefly described above and a thermoregulation device for an electric traction storage device of the electric vehicle, the thermoregulation device comprising a heat transfer fluid heating loop including an electric heater and the heat transfer fluid heating loop being activated by the air conditioning system when a transfer of calories from the thermoregulation device to the air conditioning system is necessary.

[0011] According to a particular characteristic, the heat transfer fluid heating loop is activated by the air conditioning system when the outside temperature is below -20°C.

[0012] According to another particular characteristic, the heat transfer fluid heating loop is activated by the air conditioning system when the outside temperature is in the range of -20°C to -40°C.

[0013] The invention also relates to an electric vehicle comprising an assembly as briefly described above.

[0014] Other advantages and characteristics of the present invention will appear more clearly on reading the detailed description below of a particular embodiment of the invention, with reference to the appended drawing, in which:

[0015] [Fig. 1] is a block diagram of a particular embodiment of the system according to the invention for air conditioning the passenger compartment of an electric vehicle.

[0016] With reference to [Fig. 1], a particular embodiment SCA of a system according to the invention for air conditioning the passenger compartment of an electric vehicle VE is now described by way of example.

[0017] The air conditioning system SCA provides hot / cold thermal conditioning of the passenger compartment of the vehicle VE. According to the invention, in the hot air generation mode, the air conditioning system SCA is thermally coupled to a thermoregulation device CTR of an electric traction storage unit BAT of the vehicle VE. This thermal coupling with the thermoregulation device CTR makes it possible, when the outside temperatures are very low, typically below -20°C, to recover calories present in the device CTR for the benefit of a heat pump PAC included in the air conditioning system SCA. The recovered calories allow an extension of the operating range of the heat pump PAC to temperatures well below -20°C, typically down to -40°C.

[0018] The SCA air conditioning system essentially comprises a heating, ventilation and air conditioning unit HVAC to which the aforementioned heat pump PAC is associated. The heat pump PAC is a reversible air / air type pump and is equipped with a heat exchange interface CT allowing thermal coupling with the thermoregulation device CTR.

[0019] The heat pump PAC comprises a refrigerant circuit in which are integrated in particular an electric compressor CP intended to compress a refrigerant fluid, designated "ff" hereinafter, a condenser heat exchanger CD, an evaporator heat exchanger EV, an expansion valve SD and the aforementioned heat exchange interface CT.

[0020] The condenser CD and the evaporator EV are integrated in the HVAC unit. In the HVAC unit, an air blower PS controls a forced circulation of the air AIR through the condenser CD or the evaporator EV depending on whether the hot air generation mode or the cold air generation mode is activated. The invention relates to the generation of hot air in the passenger compartment, it is the condenser CD which is active, the evaporator EV being deactivated. This is the reason why only the refrigerant loop of the condenser CD, with the compressor CP, the expansion valve SD and the heat exchange interface CT connected by refrigerant connections, is shown in [Fig. 1].

[0021] The CTR thermoregulation device of the BAT electric storage device comprises a heat transfer fluid typically in the form of a glycol water type cooling liquid, hereinafter referred to as “fc”, which is propelled by an electric pump PO through various circuit connecting members and conduits. In addition to the PO pump and the aforementioned connecting conduits, the CTR device also comprises an electric heater RE and a heat exchange circuit EB integrated in the BAT electric storage tank. The main function of the RE electric heater is to heat the heat transfer fluid fc when necessary so as to bring the internal temperature of the BAT electric storage tank to an optimal operating temperature. The invention grants the RE electric heater an additional function which is to heat the heat transfer fluid fc so as to supply calories to the PAC heat pump via the CT heat exchange interface.

[0022] As visible in [Fig.l], the heat exchange interface CT essentially comprises a heat exchanger ET and a pilot-controlled valve VA.

[0023] The heat exchanger ET comprises a refrigerant evaporator circuit cff which is integrated into the refrigerant loop of the heat pump PAC and a heat transfer fluid exchanger circuit cfc which is integrated into the thermoregulation device CTR. The cff and cfc circuits are thermally coupled to allow heat transfers.

[0024] The VA valve is here a 3-way valve which is electrically controlled. The VA valve makes it possible to determine the path of the heat transfer fluid fc in the CTR thermoregulation device according to the operating mode. The VA valve is a controlled means which, when a transfer of calories to the heat pump PAC is necessary, makes it possible to establish a heat transfer fluid heating loop, with the electric heater RE activated, which is dedicated to the transfer of calories via the heat exchanger ET.

[0025] In a conventional mode of operation of the CTR device for regulating the internal temperature of the electric storage tank BAT, the heat transfer fluid fc is propelled by the pump PO towards the valve VA, passes through the valve VA via an inlet A and an outlet B (dotted arrow), then the heat exchange circuit EB of the storage tank, the circuit cfc of the heat exchanger ET and the electric heater RE, before being taken up by the pump PO.

[0026] In the heat transfer operating mode of the thermoregulation device CTR to the heat pump PAC, the electric heater RE is activated and the aforementioned heat transfer fluid heating loop is established by appropriate control of the valve A. Thus, in the heat transfer fluid heating loop, the heat transfer fluid fc is propelled by the pump PO to the valve VA, passes through the valve VA via the inlet A and an outlet C (solid arrow), then the cfc circuit of the heat exchanger ET and the electric heater RE, before being taken up by the pump PO. The hot heat transfer fluid fc thus releases calories in the heat exchanger ET.

[0027] When the air conditioning system SCA operates in the hot air generation mode, the aforementioned operating mode of transferring calories from the thermoregulation device CTR to the heat pump PAC is activated when the outside temperatures are very low, typically below -20°C.

[0028] In the hot air generation mode, the refrigerant ff is compressed by the compressor CP and rises in temperature. The hot refrigerant ff then releases calories in the condenser CD and the air AIR forced through the latter is thus heated. The refrigerant ff then passes through the expansion valve SD and consequently drops in temperature. The cold refrigerant ff then passes through the heat exchanger ET, via the evaporator circuit cfc, before being taken up by the compressor CP for a new heat generation cycle. When the outside temperatures are very low, typically below -20°C and the heat transfer operating mode of the thermoregulation device CTR to the heat pump PAC is activated, calories generated by the electric heater RE are released by the hot heat transfer fluid fc in the heat exchanger ET.These calories available in the heat exchanger ET heat the cold refrigerant ff which passes through the evaporator circuit CFC. Thus, the contribution of calories from the electric heater RE and transferred to the refrigerant ff via the heat exchanger ET allows the heat pump PA to remain functional in the hot air generation mode down to outside temperatures well below -20°C, typically down to -40°C.

[0029] The invention is not limited to the particular embodiment which has been described here by way of example. Those skilled in the art, depending on the applications of the invention, will be able to make various modifications and variants falling within the scope of protection of the invention.

Claims

Claims

1. Cabin air conditioning system in an electric vehicle (EV), comprising a reversible air / air heat pump (PAC), characterized in that said heat pump (PAC) comprises a heat exchange interface (CT) with a thermoregulation device (CTR) of an electric traction storage unit (BAT) of said vehicle (EV), said heat exchange interface (CT) comprising a heat exchange device (ET) having a refrigerant circulation evaporator circuit (cff) integrated in a refrigerant loop (cff, CP, CD, SD) of said heat pump (PA) and a heat transfer fluid circulation exchanger circuit (cfc) integrated in said thermoregulation device (CTR) of said electric traction storage unit (BAT), and a controlled means (VA) for establishing in said thermoregulation device (CTR) of said electric traction storage unit (BAT) a heat transfer fluid heating loop (cfc, RE, PO,VA(AC)) including said heat transfer fluid circulation exchanger circuit (cfc).,

2. System according to claim 1, characterized in that said piloted means is an electrically piloted three-way valve (VA).

3. An assembly integrated in an electric vehicle (EV) comprising an air conditioning system (SCA) according to claim 1 or 2 and a thermoregulation device (CTR) of an electric traction storage unit (BAT) of said electric vehicle (EV), characterized in that said thermoregulation device (CTR) comprises a heat transfer fluid heating loop (cfc, RE, PO, VA(AC)) including an electric heater (RE), said heat transfer fluid heating loop being activated by said air conditioning system (SCA) when a transfer of calories from said thermoregulation device (CTR) to said air conditioning system (SCA) is necessary.

4. Assembly according to claim 3, characterized in that said heat transfer fluid heating loop (cfc, RE, PO, VA(AC)) is activated by said air conditioning system (SAC) when the outside temperature is below -20°C.

5. Assembly according to claim 3, characterized in that said heat transfer fluid heating loop (cfc, RE, PO, VA(AC)) is activated by said air conditioning system (SCA) when the tem-

6. outdoor temperature is in the range of -20°C to -40°C. Electric vehicle (EV) characterized in that it comprises an assembly (SCA, CTR) according to any one of claims 3 to 5.

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