Heat pump and method of managing such a heat pump

Abstract

Heat pump and method for managing such a heat pump. The invention relates to a heat pump (1) for a heating, ventilation, and air conditioning (3) system of a motor vehicle, said system comprising a heat exchanger (5) and a fan heater (7), said heat pump comprising: - a closed refrigerant flow circuit (11), - a heat exchanger (13) mounted in a front panel of said vehicle, - a compressor (15) mounted at the outlet of said heat exchanger (13). According to the invention, said heat pump includes a solenoid valve (19) comprising an inlet connected to the outlet of said compressor and two outlets supplying alternately or simultaneously said heat exchanger (5) and an additional water circuit (21) supplying said fan heater (7). The invention also relates to a method for managing such a heat pump. Figure 4

Description

Title of the invention: Heat pump and method for managing such a heat pump technical field

[0001] The invention relates to the field of thermal management of a motor vehicle passenger compartment, more specifically to the field of heating the passenger compartment by a heat pump device.

[0002] More particularly, the invention relates to a heat pump and a method for managing such a heat pump. Previous technique

[0003] The range of electric motor vehicles is one of the most important factors in the commercial success of this type of vehicle and for their acceptance on the market.

[0004] Battery electric vehicles (BEVs, an acronym for "Battery Electric Vehicle") typically include a traction battery that powers the vehicle's electric motor. The only electrical energy available to the vehicle is that stored in the traction battery.

[0005] In order to improve the capacity of traction batteries of electric motor vehicles, a solution aimed at increasing the size of the traction batteries is very penalizing, because it would make the motor vehicle more cumbersome, increase its mass and considerably increase its cost price.

[0006] A known alternative is to limit the energy consumption of the traction batteries. To do this, one solution is to control the energy consumption caused by the operation of the heating, ventilation and air conditioning system, a system frequently referred to by the acronym "HVAC" (English acronym for "Heating, Ventilation and Air-Conditioning").

[0007] The HVAC is supplied with air via a heat pump.

[0008] A first known prior art heat pump architecture is a direct heat pump.

[0009] In such a direct architecture, the refrigerant circulating in the heat pump circuit is the only heat exchanger between the outside air and the passenger compartment air. The compressor heats the high-pressure, high-temperature refrigerant circulating in the heat pump circuit, and this refrigerant is directly injected into a heat exchanger in the vehicle's HVAC system, which directly heats the air. The fluid thus directly heats the air in the passenger compartment via a heat exchanger.

[0010] In heating mode, the refrigerant takes heat from the outside air and then transfers it directly to the air blown into the passenger compartment.

[0011] In air conditioning mode, the refrigerant takes heat from the air in the passenger compartment and then transfers it directly to the outside air.

[0012] In such a direct heat pump, the number of heat exchanges is limited, which allows for a very rapid temperature rise in the air supplied for heating the passenger compartment. Thus, the direct heat pump makes it possible to limit losses and therefore obtain optimal operating performance.

[0013] However, variations in compressor operation are directly felt on the stability of the heat pump.

[0014] Also, variations in vehicle speed generate changes in air speeds at the direct heat pump air inlet.

[0015] Thus, such a direct heat pump is unstable, which impacts comfort within the passenger compartment.

[0016] A second heat pump architecture known from the prior art is an indirect heat pump.

[0017] In an indirect heat pump, the refrigerant is no longer the only thermal medium between the outside air and the air in the passenger compartment as was the case for a direct heat pump.

[0018] An additional water circuit is located between the compressor and the HVAC. The HVAC includes an air heater supplied with water by the additional water circuit.

[0019] Thus, in heating mode, instead of directly heating the passenger compartment via the HVAC exchanger, the heat pump circuit first supplies the water circuit, which then supplies the HVAC air heater.

[0020] The air conditioning mode works in the same way as in the case of the direct architecture, that is to say without the intermediary of the additional water circuit.

[0021] The HVAC system used in an electric vehicle with an indirect heat pump can be identical to that used in a combustion engine vehicle, as the HVAC system in a combustion engine vehicle includes a fan heater. Thus, compared to the HVAC system used in an electric vehicle with a direct heat pump, no adaptation of the HVAC system is necessary, which is not the case for the HVAC system used in an electric vehicle with a direct heat pump, as such an HVAC system does not include a fan heater.

[0022] Such an indirect heat pump also exhibits better stability in the temperature of the blown air, since the inertia necessary to heat the intermediate water circuit is taken advantage of.

[0023] On the other hand, given that the air is heated by means of the water circuit itself heated by the refrigerant fluid itself heated by the compressor, The heat losses inherent in heat exchange lead to suboptimal performance, particularly during the convergence phase towards a setpoint temperature.

[0024] The temperature rise of the blown air intended for heating the passenger compartment is thus slower, compared with a direct heat pump.

[0025] The indirect heat pump therefore offers a lower efficiency than a direct heat pump.

[0026] In order to optimize the energy consumption of a vehicle, in particular when the vehicle is electric, there is a need to propose a heat pump architecture which allows both rapid start-up with optimum efficiency for optimization of electrical consumption during vehicle start-ups and the possibility of having stable heating power during driving phases in steady state. Description of the invention

[0027] The present invention aims to overcome the aforementioned drawbacks, and to this end relates to a heat pump for a heating, ventilation and air conditioning system of a motor vehicle, said heating, ventilation and air conditioning system comprising a heat exchanger, capable of generating heat, and an air heater, capable of being supplied with water, said heat pump comprising: - a closed circuit for the flow of a refrigerant fluid, - a heat exchanger mounted in the front panel of said motor vehicle and capable of admitting air from outside the motor vehicle, - a compressor, mounted at the outlet of said heat exchanger, capable of drawing in and compressing said refrigerant, said heat pump being characterized in that it comprises a solenoid valve including an inlet connected to the outlet of said compressor and two outlets supplying alternately or simultaneously said heat exchanger of said heating, ventilation and air conditioning device and an additional water circuit supplying said air heater.

[0028] Thus, when the user operates the heat pump in heating mode, the solenoid valve supplies only the heat exchanger of said heating, ventilation and air conditioning device, so that the heat pump operates in direct mode as long as the duration of use of the heat pump is less than a predetermined threshold value.

[0029] Thus, for a short journey, the heat pump according to the invention makes it possible to restrict heat exchange in the heat pump circuit, which allows for a very rapid temperature rise of the blown air intended for heating the passenger compartment, thus achieving optimum efficiency of the pump. heat and therefore to optimize the vehicle's electrical consumption.

[0030] If the user continues to use the heat pump beyond the predetermined threshold value, the solenoid valve supplies only the additional water circuit supplying the air heater, so that the heat pump according to the invention operates in indirect mode.

[0031] Thus, when the operating time of the heat pump is greater than the predetermined threshold value, the indirect mode of the heat pump is preferred, this mode offering, compared with the direct mode, better stability in the temperature of the blown air insofar as one benefits from the inertia necessary to heat the additional water circuit supplying the HVAC air heater.

[0032] According to optional features of the heat pump according to the invention: - said solenoid valve is controlled by a software means adapted to: operate said heat pump in direct mode as long as the duration of use of said heat pump is less than a predetermined threshold value, said direct mode being obtained by positioning said solenoid valve so as to supply only said heat exchanger of said heating, ventilation and air conditioning device, to operate said heat pump in indirect mode when the duration of use of said heat pump exceeds said predetermined threshold value, said indirect mode being obtained by positioning said solenoid valve so as to supply only said water circuit supplying said air heater, - said software means is adapted to operate said heat pump in hybrid mode after the operation of said heat pump in direct mode and before the operation of said heat pump in indirect mode, said hybrid mode being obtained by positioning said solenoid valve so as to simultaneously supply said heat exchanger of said heating, ventilation and air conditioning device and said water circuit supplying said air heater.

[0033] The invention also relates to a method for managing a heat pump, said heat pump being, according to the invention, said method being implemented by a software means integrated into said motor vehicle and comprising the following steps aimed at: - to operate said heat pump in direct mode as long as the duration of use of said heat pump is less than a predetermined threshold value, said direct mode being obtained by positioning said solenoid valve so as to supply only said heat exchanger of said heating, ventilation and air conditioning device, - operate said heat pump in indirect mode when the duration the use of said heat pump is greater than said predetermined threshold value, said indirect mode being obtained by positioning said solenoid valve so as to supply only said water circuit supplying said air heater.

[0034] According to optional features of the management process according to the invention: - the process includes an additional step, subsequent to the said step aimed at operating said heat pump in direct mode and prior to the said step aimed at operating said heat pump in indirect mode, aimed at operating said heat pump in hybrid mode, said hybrid mode being obtained by positioning said solenoid valve so as to simultaneously supply said heat exchanger of said heating, ventilation and air conditioning device and said water circuit supplying said air heater, - said threshold value is determined according to the heat requirement necessary to reach a set temperature in the passenger compartment of said motor vehicle, - said threshold value increases when said calorific need increases, - said threshold value is determined according to the outside temperature, - said threshold value increases when the outside temperature decreases, - in a realization, the said threshold value is between approximately 5 minutes and approximately 20 minutes. Brief description of the drawings

[0035] Other features, purposes and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference should be made to the accompanying drawings in which:

[0036] [Fig-1] is a schematic diagram of a heat pump for a heating, ventilation and air conditioning system of a motor vehicle.

[0037] [Fig.2] illustrates the operation of the heat pump of the invention in direct mode.

[0038] [Fig.3] illustrates the operation of the heat pump of the invention in indirect mode.

[0039] [Fig.4] illustrates the operation of the heat pump of the invention in hybrid mode.

[0040] [Fig.5] shows the steps of the heat pump management process according to the invention.

[0041] [Fig.6] shows an alternative embodiment of the heat pump management method according to the invention. Description of the implementation methods

[0042] In the following description, elements having an identical structure or analogous functions are designated by the same reference.

[0043] Reference is made to [Fig.1] showing the operating principle of a heat pump 1 according to the invention.

[0044] The heat pump 1, also called a heat management system, is designed to manage the heat from a heating, ventilation and air conditioning device 3 of a motor vehicle, a device frequently referred to by the acronym "HVAC" (English acronym for "Heating, Ventilation and Air-Conditioning").

[0045] The heat pump 1 is adapted to operate either in direct mode, or in indirect mode, or in a hybrid mode in which the heat pump operates both in direct mode and in indirect mode.

[0046] To this end, the HVAC 3 used in the context of the present invention and controlled by the heat pump 1 includes a heat exchanger 5, capable of generating heat, frequently referred to by the English expression "heater core". As will be seen in the remainder of the description, the heat exchanger 5 of the HVAC 3 is used when the heat pump operates in direct mode or in hybrid mode and when the heat pump operates in heating mode.

[0047] The HVAC 3 further includes a water-supplied air heater 7. The air heater 7, known to those skilled in the art, is a heat exchanger capable of exchanging heat between a circuit containing hot water and blown air, the blown air being connected to the HVAC blower and heating the vehicle's passenger compartment. As will be seen later in the description, the air heater 7 of the HVAC 3 is used when the heat pump operates in indirect or hybrid mode and when the heat pump operates in heating mode.

[0048] The HVAC 3 also includes an evaporator 9, capable of generating cold, used regardless of the operating mode of the heat pump and when the heat pump is operating in air conditioning mode.

[0049] The heat pump 1 includes a closed circuit for the flow of a refrigerant fluid 11.

[0050] In the direction of the flow of the refrigerant fluid 11, the heat pump 1 includes a heat exchanger 13 mounted in the front facade of the motor vehicle and capable of admitting air from outside the motor vehicle.

[0051] The heat exchanger 13 is likely to behave as an evaporator or as a condenser depending on whether the heat pump 1 is operating in heating mode or in cooling mode.

[0052] At the outlet of the heat exchanger 13, the heat pump 1 includes a compressor 15 supplied with electrical energy by an accumulator 17 and capable of drawing in and compressing the refrigerant fluid 11.

[0053] According to the invention, the heat pump 1 includes a solenoid valve 19 comprising an inlet connected to the outlet of the compressor 15 and two outlets supplying the heat exchanger 5 of the HVAC 3 and / or an additional water circuit 21 supplying the air heater 7 of the HVAC 3.

[0054] Thus, when the solenoid valve 19 supplies the heat exchanger 5 of the HVAC 3, the heat pump 1 operates in direct mode.

[0055] Similarly, when the solenoid valve 19 supplies the water circuit 21 supplying the air heater 7 of the HVAC 3, the heat pump 1 operates in indirect mode.

[0056] Finally, when the solenoid valve 19 supplies both the heat exchanger 5 of the HVAC 3 and the water circuit 21 supplying the air heater 7 of the HVAC 3, the heat pump 1 operates in hybrid mode.

[0057] Reference is made to [Fig.2] showing the operation of the heat pump 1 in direct mode.

[0058] The path of the refrigerant in the heat pump 1 is shown in dotted lines when the heat pump 1 is operating in direct mode.

[0059] In heating mode, the refrigerant 11 is admitted in liquid form into the heat exchanger 13 mounted in the front of the vehicle at a temperature lower than the temperature outside the vehicle.

[0060] The heat exchanger 13 admits air from outside the vehicle. The outside air admitted into the heat exchanger 13, the temperature of which is lower than the temperature of the refrigerant 11 admitted into the heat exchanger 13, heats the refrigerant 11.

[0061] At the outlet of the heat exchanger 13, which behaves here as an evaporator, the refrigerant 11 is introduced in gaseous state into the compressor 15.

[0062] The compressor 15 compresses the refrigerant 11 at high pressure and heats it to high temperature.

[0063] In this direct mode, the solenoid valve 19 is controlled so that the refrigerant 11 is directly introduced into the heat exchanger 5 of the HVAC 3.

[0064] The heat exchanger 5 of the HVAC 3 heats the air blown into the passenger compartment, represented by arrow 23.

[0065] The refrigerant 11 is then expanded before being reintroduced in liquid form into the heat exchanger 13 mounted in the front of the vehicle.

[0066] In air conditioning mode, the refrigerant 11 exiting the compressor 15 is sent to the heat exchanger 13 mounted in the front panel of the vehicle. The heat exchanger 13 then acts as a condenser. From the heat exchanger 13, the refrigerant 11 is sent to the evaporator 9 of the HVAC 3. By means of a fan integrated into the HVAC 3, an exchange is created between the outside air 23 and the evaporator 9 of the HVAC 3, which allows for cooling. interior design.

[0067] Reference is made to [Fig.3] showing the operation of the heat pump 1 in indirect mode.

[0068] The path of the refrigerant in the heat pump 1 is shown in dotted lines when the heat pump 1 is operating in indirect mode.

[0069] In heating mode, the refrigerant 11 is admitted in liquid form into the heat exchanger 13 mounted in the front of the vehicle at a temperature lower than the temperature outside the vehicle.

[0070] The heat exchanger 13 admits air from outside the vehicle. The outside air admitted into the heat exchanger 13, the temperature of which is lower than the temperature of the refrigerant 11 admitted into the heat exchanger 13, heats the refrigerant 11.

[0071] At the outlet of the heat exchanger 13, which behaves here as an evaporator, the refrigerant 11 is introduced in gaseous state into the compressor 15.

[0072] The compressor 15 compresses the refrigerant 11 at high pressure and heats it to high temperature.

[0073] In this indirect mode, the solenoid valve 19 is controlled so that the refrigerant 11 is introduced into the additional water circuit 21.

[0074] The water circuit supplies the air heater 7 of the HVAC 3 which heats the air blown into the passenger compartment, represented by the arrow 25. The air is therefore heated here by means of the water circuit 21, the water itself being heated by the refrigerant 11, itself heated by the compressor 15 which has compressed and heated the refrigerant 11.

[0075] The refrigerant 11 is then expanded before being reintroduced in liquid form into the heat exchanger 13 mounted in the front of the vehicle.

[0076] The air conditioning mode is identical to that described for the direct mode.

[0077] Reference is made to [Fig.4] showing the operation of the heat pump 1 in hybrid mode.

[0078] In hybrid mode, the solenoid valve 19 is controlled so that the refrigerant 11 is introduced both into the heat exchanger 5 of the HVAC 3 and into the additional water circuit 21.

[0079] The air blown into the passenger compartment, represented by arrow 27, is heated both through the water circuit 21 and by the heat exchanger 5 of the HVAC 3.

[0080] According to one provision of the invention, the solenoid valve 19 is controlled according to the life situations of the motor vehicle by means of a heat pump management method 1 implemented by a software means which can be integrated into the motor vehicle.

[0081] To this end, the software means is programmed to implement the process of the invention. The software means is for example integrated into a computer of the motor vehicle, for example in the electronic management box known as the "BSI", an acronym for "Intelligent Servicing Box".

[0082] Reference is made to [Fig.5] showing the steps of the heat pump management process 1 according to the invention.

[0083] When starting the vehicle, if the user activates the heat pump 1 in heating mode, the method and the heat pump 1 according to the invention are adapted to operate the heat pump 1 in direct mode (step E10) as long as the duration of use of the heat pump 1 is less than a predetermined threshold value.

[0084] Using the heat pump 1 in direct mode allows, for a short journey, to restrict the heat exchanges in the circuit of the heat pump 1, which allows a very rapid temperature rise of the blown air intended for heating the passenger compartment, which allows an optimum efficiency of the heat pump 1.

[0085] If the user continues to use the vehicle and the heat pump 1 beyond the predetermined threshold value, the method and the heat pump 1 according to the invention are adapted to operate the heat pump 1 in indirect mode (step E20).

[0086] Thus, when the operating time of the heat pump is greater than the predetermined threshold value, the indirect mode of the heat pump 1 is preferred, this mode offering, compared with the direct mode, better stability in the temperature of the blown air insofar as we benefit from the inertia necessary to heat the additional water circuit 21 supplying the air heater 7 of the HVAC 3.

[0087] Reference is made to [Fig.6] showing a variant of the heat pump 1 management method according to the invention.

[0088] The method and the heat pump 1 according to the invention can be adapted to operate the heat pump 1 in hybrid mode (Eli stage) after its operation in direct mode and before its operation in indirect mode.

[0089] This allows the indirect mode to be reached gradually, which further increases the stability of the heat pump 1 and makes the transition from direct mode to indirect mode imperceptible to the user.

[0090] In one embodiment of the invention, the threshold value can be determined based on the heating requirement needed to reach a setpoint temperature in the passenger compartment of the motor vehicle. The threshold value increases as the heating requirement increases. Thus, the operating time of the heat pump 1 in direct mode increases as the heating requirement increases.

[0091] The heating requirement can be determined based on the setpoint temperature defined in the passenger compartment and, for example, based on the outside temperature and / or the outside humidity level. More specifically, the threshold value can be determined depending on the outside temperature. The threshold value increases when the outside temperature decreases.

[0092] By way of non-limiting example, the threshold value may be between approximately 5 minutes and approximately 20 minutes.

[0093] For example, if the outside temperature is about -20°C, the threshold value is between about 15 minutes and about 20 minutes, while if the outside temperature is about 0°C the threshold value is between about 5 minutes and about 10 minutes.

[0094] As will be understood, the present invention is not limited to the embodiments of this heat pump and of this method of managing such a heat pump, described above only by way of illustrative examples, but on the contrary it encompasses all variants involving the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

Claims

Demands

1. Heat pump (1) of a heating, ventilation and air conditioning (3) device of a motor vehicle, said heating, ventilation and air conditioning (3) comprising a heat exchanger (5), capable of generating heat, and a fan heater (7), capable of being supplied with water, said heat pump (1) comprising: - a closed circuit for the flow of a refrigerant (11), - a heat exchanger (13) mounted in a front panel of said motor vehicle and capable of admitting air from outside the motor vehicle, - a compressor (15), mounted at the outlet of said heat exchanger (13) mounted in said front panel of said motor vehicle, capable of drawing in and compressing said refrigerant (11),said heat pump (1) being characterized in that it comprises a solenoid valve (19) including an inlet connected to the outlet of said compressor (15) and two outlets supplying alternately or simultaneously said heat exchanger (5) of said heating, ventilation and air conditioning device (3) and an additional water circuit (21) supplying said air heater (7).

2. Heat pump (1) according to claim 1, characterized in that said solenoid valve (19) is controlled by a software means adapted to: - operate said heat pump (1) in direct mode as long as the duration of use of said heat pump (1) is less than a predetermined threshold value, said direct mode being obtained by positioning said solenoid valve (19) so as to supply only said heat exchanger (5) of said heating, ventilation and air conditioning device (3), - operate said heat pump (1) in indirect mode when the duration of use of said heat pump (1) is greater than said predetermined threshold value, said indirect mode being obtained by positioning said solenoid valve (19) so as to supply only said water circuit (21) supplying said air heater (7).

3. Heat pump (1) according to claim 2, characterized in that said software means is adapted to operate said heat pump (1) in hybrid mode after the operation of said heat pump (1) in direct mode and before the operation of said heat pump (1) in indirect mode, said mode hybrid being obtained by positioning said solenoid valve (19) so as to simultaneously supply said heat exchanger (5) of said heating, ventilation and air conditioning device (3) and said water circuit (21) supplying said air heater (7).

4. A method for managing a heat pump (1), said heat pump (1) being according to claim 2 or 3, said method being implemented by a software means integrated into said motor vehicle and comprising the following steps aimed at: - operating said heat pump (1) in direct mode (step E10) as long as the duration of use of said heat pump (1) is less than a predetermined threshold value, said direct mode being obtained by positioning said solenoid valve (19) so as to supply only said heat exchanger (5) of said heating, ventilation and air conditioning device (3), - operating said heat pump (1) in indirect mode (step E20) when the duration of use of said heat pump (1) is greater than said predetermined threshold value,said indirect mode being obtained by positioning said solenoid valve (19) so as to supply only said water circuit (21) supplying said air heater (7).

5. Method of managing a heat pump (1) according to claim 4, characterized in that it comprises an additional step, subsequent to said step for operating said heat pump (1) in direct mode (step E10) and prior to said step for operating said heat pump (1) in indirect mode (step E20), for operating said heat pump (1) in hybrid mode (step Eli), said hybrid mode being obtained by positioning said solenoid valve (19) so as to simultaneously supply said heat exchanger (5) of said heating, ventilation and air conditioning device (3) and said water circuit (21) supplying said air heater (7).

6. Management method according to any one of claims 4 or 5, characterized in that said threshold value is determined as a function of the heat requirement necessary to reach a setpoint temperature in the passenger compartment of said motor vehicle.

7. Management method according to claim 6, characterized in that said threshold value increases when said calorific need increases.

8. Management method according to any one of claims 4 or 5, characterized in that said threshold value is determined as a function of the outside temperature.

9. Management method according to claim 8, characterized in that said threshold value increases when the outside temperature decreases.

10. Management method according to any one of claims 4 to 9, characterized in that said threshold value is between about 5 minutes and about 20 minutes.

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