automotive heat pump system

Abstract

The invention provides a motor vehicle heat pump system (14). The heat pump system (14) comprises: a circuit (16) with an evaporator, a compressor (34) configured to compress a heat transfer fluid, a condenser, and an expansion valve (38); and a control unit (18). The control unit (18) is configured to act on the circuit to heat the evaporator to a predetermined temperature of at least 55°C, using the compressor and condenser, in order to reduce the presence of microorganisms on said evaporator. The invention also provides a motor vehicle and a method for disinfecting the heat pump system. Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Heat pump system for motor vehicles

[0001] The invention relates to a motor vehicle heat pump system. More specifically, the invention deals with the disinfection of a motor vehicle heat pump system. The invention proposes a method for the microbiological disinfection of a motor vehicle heat pump system. The invention also relates to a motor vehicle equipped with a heat pump system.

[0002] A heat pump makes it possible to heat the passenger compartment of a vehicle while reducing the need for primary energy. Such a system improves passenger comfort while optimizing the energy autonomy of the motor vehicle.

[0003] Typically, a heat pump system comprises a closed loop in which a heat transfer fluid circulates. The loop connects a condenser, a compressor, an expansion valve, and an evaporator; and allows a transfer of heat between a hot source and a cold source; in this case, the passenger compartment.

[0004] The compressor draws in and compresses the heat transfer fluid in its gaseous phase and conveys it to the condenser. Downstream, the condenser receives this pressurized heat transfer fluid. The condenser is a heat exchanger in which the heat transfer fluid changes from a gaseous to a liquid state. The fluid undergoes a phase change cycle. In the condenser, the heat transfer fluid releases some of its thermal energy as it changes into a liquid phase. This energy is recovered by air, which forms a second flow passing through the condenser, to heat the passenger compartment.

[0005] Next, the heat transfer fluid reaches the expansion valve where its pressure and temperature decrease. Then, in the evaporator, the heat transfer fluid changes from a liquid to a gaseous phase. During this phase change, the heat transfer fluid absorbs heat from the surrounding air passing through the evaporator. The evaporator becomes cooler than the outside of the vehicle. At the evaporator outlet, the heat transfer fluid in its gaseous state is again drawn into the compressor and thus begins a new compression and expansion cycle.

[0006] When the vehicle stops, the evaporator remains cold, which promotes condensation. This condensation encourages the growth of mold and various types of bacteria, both on the surfaces of the evaporator and on its associated filter. These bacteria generate undesirable odors that are unpleasant for the user.

[0007] It is known that cabin air filters are not always replaced with the regularity recommended by the manufacturer, or may be incorrectly installed. When the The air filter is no longer functioning properly, allowing dust, and therefore solid organic matter suspended in the air, to pass through. This organic matter enters the evaporator and accumulates there. This accumulation is amplified by the humidity within the evaporator due to condensate runoff, which in turn amplifies microbial growth responsible for the release of volatile organic compounds. This phenomenon intensifies the unpleasant odors that can be perceived by vehicle occupants when the air passing through the evaporator is blown into the passenger compartment. Air quality is degraded, and the perceived quality diminishes.

[0008] To prevent the proliferation of microorganisms in the evaporator, passive systems are known, for example, evaporators with an antibacterial coating, air filters containing suitable chemicals; or active systems. Active systems include ionizers, ozonizers, or other devices. However, known systems are relatively ineffective or very expensive, which is incompatible with the economic constraints of automobile manufacturers. Furthermore, even when effective, known systems exhibit only partial efficiency, which decreases significantly over time.

[0009] Document FR3111849A1 describes a motor vehicle air conditioning and heating system. The air conditioning and heating system includes a cooling circuit comprising an evaporator and an air filter for filtering the air passing through the evaporator. The air conditioning and heating system includes a heating device configured to warm the air contained in the space separating the air filter from the evaporator. The heating device includes an electric heating element or a heating circuit designed for the circulation of a heat transfer fluid directly heated by the internal combustion engine. Thanks to this heating device, the proliferation of microorganisms is prevented, and with it, the generation of unpleasant odors.

[0010] However, such a system is complex. Its operation requires dedicated power supplies. The electric solution reduces the size, but its operation requires significant energy, which negatively impacts the vehicle's primary energy consumption. The solution with the circuit coupled to the internal combustion engine benefits from the engine's heat but remains bulky and adds weight to the vehicle. Furthermore, its effectiveness depends on the internal combustion engine's warm-up time.

[0011] Document US5385028A describes a vehicle comprising a pump system heat. The system comprises two loops, including a primary loop connecting a compressor, an accumulator, and a reversing valve. The system also includes a reversing loop connecting the reversing valve, a front heat exchanger, an expansion unit, and a cabin heat exchanger. The in- valve The dispensing unit is adapted to reverse the flow direction in the second loop.

[0012] When the system is in the cooling phase, and in the event of a change in the vehicle's operating mode, the system stops, interrupting the flow of refrigerant in the passenger compartment heat exchanger. This leads to condensation, which is conducive to the growth of odor-causing bacteria. The passenger compartment heat exchanger fan then runs at maximum speed to remove the humidity. The fan then slows down or stops, and the reversing valve switches to the heating phase to warm the passenger compartment heat exchanger using the hot, pressurized refrigerant. This system sanitizes the evaporator by drying it.

[0013] However, this document does not offer a satisfactory solution for eliminating bad odors once bacteria have already developed. Furthermore, this system remains complex, and its effectiveness depends on both the temperature and the humidity level of the surrounding air.

[0014] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to provide a heat pump system for motor vehicles that is configured to reduce the presence of microorganisms while remaining simple and efficient. The invention also aims to optimize the simplicity and energy consumption of a heat pump system for a motor vehicle.

[0015] According to a first aspect, the invention relates to a motor vehicle heat pump system, the heat pump system comprising: a circuit with a first heat exchanger, a compressor configured to compress a heat transfer fluid, a second heat exchanger, and an expansion valve; remarkable in that the heat pump system further comprises a control unit which is configured to act on the circuit by actuating at least the compressor and using the second heat exchanger to heat the first heat exchanger to a predefined temperature of at least 55°C, so as to eliminate all or part of the microorganisms that may be present in said first heat exchanger.

[0016] It will be understood that the invention relates to a thermodynamic system; such as a heat pump system; of a motor vehicle, the thermodynamic system comprising: a first heat exchanger such as an evaporator, a compressor configured to compress a heat transfer fluid, a second heat exchanger such as a condenser; remarkable in that the thermodynamic system further comprises a control unit which is configured to control at least the compressor in order to heat the first heat exchanger to a predefined temperature, using thermal energy collected by the second heat exchanger, in order to reduce the presence of and / or eliminate microorganisms in and / or covering said first heat exchanger.

[0017] Preferably, the first heat exchanger is an evaporator.

[0018] Preferably, the second heat exchanger is a condenser.

[0019] Preferably, the predefined temperature is between 60°C and 90°C; preferably between 65°C and 80°C, and / or at least equal to 70°C.

[0020] Preferably, the heat pump system further comprises a filter associated with the first heat exchanger, defining a first zone between said filter and the first heat exchanger; the control unit being configured to act on the circuit in order to heat the first zone to the predefined temperature. In other words, the control unit is configured to act on the circuit by activating at least the compressor and using the second heat exchanger to heat the first zone to a predefined temperature of at least 55°C, so as to eliminate all or part of the microorganisms that may be present in said first zone.

[0021] Preferably, the control unit is configured to maintain the preset temperature for a period of between 5 minutes and 20 minutes.

[0022] Preferably, the regulator is a pilot-operated regulator, and the control unit is configured to control the pilot-operated regulator.

[0023] Preferably, the first heat exchanger includes a first fan and the second heat exchanger includes a second fan; the control unit is further configured to operate the second fan and to stop or slow down the first fan in order to heat the first heat exchanger to the predefined temperature.

[0024] Preferably, the control unit is configured to command a temperature rise from an ambient temperature to the predefined temperature, said temperature rise comprising a duration of between 10 minutes and 30 minutes, preferably between 15 minutes and 20 minutes.

[0025] Preferably, the predefined temperature is a first temperature, and the control unit is configured to calculate a first time between a given instant and a date of last heating of the first heat exchanger at the first temperature, to compare the first time to a predefined time; and when the first time is greater than or equal to the predefined time, to heat the first heat exchanger to a second temperature greater than the first temperature, by means of the compressor and the second heat exchanger.

[0026] Preferably, the control unit is configured to act on the circuit in order to heat the first heat exchanger to a predefined temperature of at least 55°C, using the heat transfer fluid.

[0027] Preferably, the circuit comprises a heat transfer fluid, such as a compressible gas.

[0028] Preferably, the heat pump system includes an air duct in which is arranged the evaporator, and a temperature probe intended to measure a temperature at the level of the evaporator.

[0029] Preferably, the first fan is axial flow, and the second fan is radial flow.

[0030] Preferably, the first fan is an evaporator fan; and / or the second fan is a condenser fan.

[0031] Preferably, the first zone is an evaporator zone.

[0032] According to another aspect, the invention relates to a motor vehicle comprising a heat pump system, notable in that the heat pump system conforms to the invention, and the motor vehicle includes an electric battery system for the propulsion of the motor vehicle, said electric battery system being configured to power the heat pump system; preferably the first heat exchanger comprises a first internal network with a first internal volume, and the second heat exchanger comprises a second internal network with a second internal volume smaller than the first internal volume.

[0033] Preferably, the motor vehicle is capable of being connected to an external electrical power source in order to recharge the electric battery system, the control unit being configured to heat the first heat exchanger to the predefined temperature when the motor vehicle is connected to the external power source.

[0034] Preferably, the vehicle includes means for detecting a user in a passenger compartment, the control unit being configured to heat the first heat exchanger to the predefined temperature when the passenger compartment is free of a user.

[0035] According to another aspect, the invention relates to a method for eliminating microorganisms in a heat pump system for a motor vehicle comprising a passenger compartment, notable in that the heat pump system conforms to the invention, and the method comprises the following steps: heating the passenger compartment by the second heat exchanger, then heating the first heat exchanger to the predefined temperature of at least 55°C by means of the compressor and the second heat exchanger so as to eliminate microorganisms in said first heat exchanger.

[0036] According to another aspect, the invention relates to the use of a heat transfer fluid to heat a heat exchanger of a motor vehicle in order to eliminate microorganisms in said heat exchanger, the heat exchanger being optionally a first heat exchanger of a heat pump system according to the invention.

[0037] According to another aspect, the invention relates to the use of a motor vehicle heat pump system to heat at least a portion of said system of heat pump at a predefined temperature of at least 55°C for a period of between 5 minutes and 20 minutes, when the outside temperature of the motor vehicle is greater than or equal to 29°C, said heat pump system being capable of heating a passenger compartment of the motor vehicle; and the system being optionally in accordance with the invention.

[0038] According to another aspect, the invention relates to the use of a motor vehicle heat pump to disinfect said heat pump, said heat pump being capable of heating a passenger compartment of the motor vehicle; the heat pump optionally forming a heat pump system according to the invention.

[0039] According to another aspect, the invention relates to the use of an evaporator of a motor vehicle heat pump system circuit to eliminate or reduce the presence of microorganisms covering said evaporator, the motor vehicle comprising a heating system with the heat pump which has a loop connecting said evaporator, a compressor, an expansion valve; the system being optionally in accordance with the invention.

[0040] The invention will be well understood and other aspects and advantages will become clear upon reading the following description given with reference to the attached figures listed below.

[0041] [Fig-1] The [Fig.1] is a side view of a vehicle according to the invention.

[0042] [Fig.2] The [Fig.2] is a diagram of a heat pump system according to the invention.

[0043] [Fig.3] The [Fig.3] is a diagram of a method for eliminating microorganisms in a heat pump system for a motor vehicle according to the invention.

[0044] In the following description, the term "include" is synonymous with "include" and is not limiting in that it permits the presence of other elements in the motor vehicle or other steps in the process to which it relates. It is understood that the term "include" includes the terms "consist of." The terms "external" and "internal" shall respectively designate what is directed outward from the vehicle and inward from the vehicle.

[0045] In this description, the term “longitudinal”, the term The terms "longitudinally," "transversely," and "transversely" are used in relation to the vehicle's frame of reference, within the mounting configuration. "Longitudinal" refers to the vehicle's primary direction of travel. "Transverse" refers to a direction perpendicular to the vehicle's primary direction of travel. "Front" refers to the vehicle's primary direction of travel. "Rear" refers to the opposite of the front of the vehicle. The X-axis represents the longitudinal direction, the Y-axis represents the transverse direction, and the Z-axis represents the vertical direction.

[0046] In this description, the ranges of values ​​include the bounds that define them. limit.

[0047] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0048] Figure 1 shows a motor vehicle 10 according to the invention. The motor vehicle 10 is shown in side view, along the transverse direction, along the Y axis. The arrow on the X axis is directed towards the front of the vehicle.

[0049] The motor vehicle 10 includes a passenger compartment 12. The passenger compartment 12 forms a space intended to accommodate users (not shown), such as a driver and passengers accompanying the driver. The passenger compartment 12 forms an enclosure isolated from the environment of the vehicle 10.

[0050] The motor vehicle 10 includes a heat pump system 14. The heat pump system 14 is associated with the passenger compartment 12. It is at least capable of heating the passenger compartment 12, and in particular the air in the passenger compartment 12. It is capable of heating the passenger compartment to a temperature higher than the ambient temperature of the motor vehicle 10.

[0051] The heat pump system 14 includes a circuit 16. The circuit may be a passenger compartment heating circuit 12. The heat pump system 14 includes a control unit 18. The control unit 18 is configured to control the circuit 16 so as to heat at least a part, or a zone, or a chamber, or a surface of the heat pump system 14; so as to eliminate microorganisms therein. The control unit 18 is configured to control the circuit 16 so as to heat at least a part, or a zone, or a chamber, or a surface of the heat pump system 14; to a predefined temperature. The control unit 18 is in disinfection mode during the temperature rise and during the maintenance at the predefined temperature.

[0052] The preset temperature is greater than or equal to 55°C; preferably 60°C. The preset temperature is less than or equal to 90°C, preferably 80°C. The preset temperature is between 55°C and 90°C, preferably between 60°C and 80°C. Optionally, the preset temperature is at least 70°C. These temperatures offer a compromise between the efficiency of microorganism elimination, energy consumption, and / or the preservation of the materials of the heat pump system 14. Indeed, air ducts communicating with the system include plastic materials.

[0053] According to one option, the heat pump system 14 is reversible. The reversible heat pump system 14 is also capable of actively cooling the passenger compartment. It is capable of cooling the passenger compartment by injecting air that is cooler than the surrounding environment of the vehicle.

[0054] The motor vehicle 10 includes an electric battery system 20. The The electric battery system 20 can be a propulsion system in that it is capable of powering the drive means of the motor vehicle. The drive means include, in particular, an electric motor 22 coupled to wheels. In the present illustration, the electric motor 22 is coupled to the rear wheels; however, the invention also considers a vehicle in which the electric motor 22 is coupled to the front wheels. The motor vehicle 10 is optionally an electric vehicle in that its energy used for propulsion is essentially, and preferably exclusively, electrical.

[0055] The motor vehicle 10 includes means 24 for connecting to an external electrical network (not shown). The connection means 24, possibly consisting of a plug, are electrically connected to the electric battery 20 in order to recharge it.

[0056] The activation of the disinfection mode by the control unit can be conditioned by the connection of the connection means 24 to an external electrical network, or according to a state of charge of the electric battery system 20, and / or when the vehicle has remained inactive for a period greater than a threshold duration.

[0057] Figure 2 shows a heat pump system 18 for a motor vehicle. The motor vehicle is preferably identical or similar to that shown in relation to Figure 1.

[0058] The control unit 18 comprises a memory 26 and a computer 28. The control unit 18 may be a computer or a programmable electronic card. The memory 26 is capable of storing a computer program comprising code instructions, which, when executed by the computer 28, enable the execution of a microorganism elimination process according to the invention, and in particular as described below.

[0059] The heat pump system 14 includes a circuit 16. The circuit 16 transports a heat transfer fluid (not shown) in its conduits 30. These conduits 30 connect a first heat exchanger 32, a compressor 34, a second heat exchanger 36 and an expansion valve 38. The first heat exchanger 32 can be an evaporator, and the second heat exchanger 36 can be a condenser.

[0060] The control unit 18 is configured to act on the circuit 16. The control unit 18 is configured to heat the first heat exchanger 32 to a predefined temperature, referred to as the first temperature; of at least 55°C. The predefined temperature is between 60°C and 90°C; preferably between 65°C and 80°C, and / or at least equal to 70°C.

[0061] Thus, the heat pump system 14 manages to counter the formation and presence of microorganisms by its own means, in particular its own heat exchangers (32; 36) and its compressor 34.

[0062] The first heat exchanger 32 is heated by the heat transfer fluid, which is itself heated in the compressor 34 and the second heat exchanger 36. The control unit 18 thus manages the reduction of microorganisms potentially present on the first heat exchanger 32. The compressor 34 compresses the heat transfer fluid. The compressor 34 draws the heat transfer fluid from the first heat exchanger 32 and pumps it to the second heat exchanger 36.

[0063] The first heat exchanger 32 comprises a first internal network with a first internal volume. The second heat exchanger 36 comprises a second internal network with a second internal volume smaller than the first internal volume. The internal networks guide the flow of heat transfer fluid through the exchangers; they are the sites of heat exchange. The internal volumes are the free volumes for containing the heat transfer fluid. Thus, the first heat exchanger 32 more readily receives heat from the external environment.

[0064] The preset temperature is greater than or equal to: 55°C, or 60°C, or 70°C. The preset temperature is between 60°C and 90°C; preferably between 65°C and 80°C, more preferably equal to 70°C. The control unit 18 is configured to maintain the preset temperature for a period of between 5 minutes and 20 minutes; optionally equal to 5 minutes.

[0065] The invention simplifies the implementation of the disinfection function in the heat pump system 14. Furthermore, it benefits from the thermal efficiency of its circuit 16. Thanks to heat exchange and phase changes, the efficiency is greater than: 1; preferably 2; more preferably 3. The thermodynamic efficiency can be measured for an outside temperature of 25°C and a predefined temperature of 55°C. Thus, the invention optimizes the simplicity and primary energy consumption of the heat pump system 14.

[0066] The invention achieves a disinfection function without a combustion engine. This reduces greenhouse gas emissions. A disinfection cycle can be initiated when the vehicle is in an enclosed space, without risk of poisoning.

[0067] The heat pump system 14 further includes a filter 40, also called the first filter. The filter is located opposite the first heat exchanger 32. The heat pump system 14 includes a first passage 42, such as an evaporator passage, in which the first heat exchanger 32 and the filter 40 are located. The first passage 42 draws air from the vehicle's environment and directs it to the first heat exchanger 32. The filter 40 removes dust and organic matter that could clog the first heat exchanger 32 and promote the growth of microorganisms. According to one option of the invention, the heat pump system 14 further includes a second filter 41 associated with the second heat exchanger.

[0068] The first passage 42 includes a first zone 44, such as an evaporator zone, between the filter 42 and the first heat exchanger 32. The control unit 18 is adapted to act on the circuit 16 in order to heat the first zone 44 to the predefined temperature. By convection, the filter 40 is also heated to the predefined temperature. This allows it to be thermally treated and to reduce or eliminate any possible presence of microorganisms. Similarly, the control unit 18 is adapted to act on the circuit 16 in order to heat the second filter 41, in order to reduce or eliminate any possible presence of microorganisms.

[0069] The first heat exchanger 32 includes a first fan 46, such as an evaporator fan. The first fan 46 may be axial flow; that is, with flow along the axis of rotation of said first fan. This type of fan increases the airflow and therefore the heat exchange. The second heat exchanger 36 includes a second fan 48, such as a condenser fan. The second heat exchanger 36 and the second fan 48 are arranged on the passenger compartment side 12. They are in fluidic communication with the passenger compartment 12. The second fan 48 may be radial flow. Such a fan allows for a more compact arrangement and control of noise emissions.

[0070] According to an alternative of the invention, the first fan (represented in dotted lines) is arranged upstream of the first heat exchanger 32. It is in front of the first heat exchanger 32. In this alternative, the filter 42 is arranged between the first fan and the first heat exchanger 32.

[0071] Each of the fans (46; 48) is capable of sending or drawing air through the associated heat exchanger. This increases the heat exchange and the heating capacity of the circuit 16. In order to heat the first heat exchanger 32, the control unit 18 controls and operates the second fan 48 and stops or slows down the first fan 46. Thus, the preset temperature is reached more quickly in the first heat exchanger 32. The energy required for heating remains lower. When the first heat exchanger 32 is covered on one side by the filter 40, the energy requirement is further reduced.

[0072] The fans are optional. The heat pump system may include forward-facing air inlets configured to force air circulation when the vehicle is moving. The system may include air scoops.

[0073] According to one option, the heat pump system 14 is reversible. The circuit 16 includes a four-way valve 50. The four-way valve 50 allows the pressurized outlet of the compressor 34 to be selectively connected to the first heat exchanger 32 or to the second heat exchanger 36. This arrangement makes it easy to heat the first heat exchanger 32, and also to cool the passenger compartment when The first fan 46 is activated. Thus, circuit 16 can become a passenger compartment cooling circuit. The roles of the first heat exchanger 32 and the second heat exchanger 36 can be reversed. The heat exchangers (32; 36) can be referred to as "evaporative condensers".

[0074] The four-way valve 50 is an optional aspect of the invention. The compressor can be reversible in order to reverse the direction of flow through the heat exchangers. In this case, the compressor is directly connected to the first heat exchanger and the second heat exchanger.

[0075] According to one option of the invention, the expansion valve 38 is a pilot-operated expansion valve, such as an electronic expansion valve. The control unit 18 is configured to control said pilot-operated expansion valve between a state with expansion and a state without expansion. The pilot-operated expansion valve includes pilot-operated means for modifying its pressure drop. In the state without expansion, the heat transfer fluid flows through the pilot-operated expansion valve while maintaining its pressure. It can expand in the heat exchanger arranged downstream. The heat transfer fluid retains its temperature. Thus, when the control unit 18 forces expansion in the state with expansion, the heat transfer fluid cools down at the outlet of the pilot-operated expansion valve. When the control unit 18 removes the expansion in the state without expansion, the heat transfer fluid remains at the same temperature. When it has been heated by the compressor, it remains hot. Its temperature rises higher than with expansion. The temperature can be greater than or equal to: 70°C, or 90°C.

[0076] Thus, the heat transfer fluid heats the first heat exchanger to the predefined temperature. Depending on the circuit control, particularly the four-way valve 50, the second heat exchanger can be heated to the predefined temperature. Therefore, the invention eliminates all or part of the microorganisms that may be present in the heat exchanger on the environmental or passenger compartment side. To heat the second heat exchanger on the passenger compartment side to the predefined temperature, the compressor compresses the heat transfer fluid, which heats it, and then injects it into the second heat exchanger. The heat transfer fluid then passes through the expansion valve, which is in a non-expansion state, so it remains at approximately the same temperature. The fluid then passes through the first heat exchanger where it expands. This expansion results in a drop in its temperature.Simultaneously, the heat transfer fluid absorbs heat from the environment to warm itself before being heated again by the compressor. It's clear that this heating method remains simple and allows for high temperatures to be reached.

[0077] The control unit 18 is configured to raise the temperature from the ambient temperature to the predefined temperature. The ambient temperature is also called the outside temperature. It corresponds to the temperature of the environment. It can be measured by a sensor on the vehicle. The The temperature ramp-up can be gradual, with a constant increase in temperature. It lasts between 10 and 30 minutes, preferably between 15 and 20 minutes. These extended temperature ramp-up times avoid power spikes, simplifying power management.

[0078] The control unit 18 is configured to calculate or retrieve from memory 26 the initial time elapsed between a given instant, for example, when the vehicle is activated, and the date of the last heating of the first heat exchanger 32 to the predefined temperature; in this case, the first temperature. The control unit 18 is capable of comparing this initial time to a reference time and heating the first heat exchanger 32 to a second temperature if the initial time is greater than or equal to the reference time. The second temperature is higher than the first temperature. This mode is designated as "boost" mode, which allows for a second level of disinfection to enhance the elimination of microorganisms.

[0079] The motor vehicle is capable of being connected to an external electrical power source (not shown) via the connection means 24. This connection of the connection means 24 allows the electric battery system 20 to be electrically recharged. The control unit 18 is configured to heat the first heat exchanger 32 to the predefined temperature when the motor vehicle is connected to the external power source. The control unit 18 is capable of detecting an electrical supply via the connection means 24.

[0080] The control unit 18 is capable of heating the first heat exchanger 32 to the predefined temperature when the vehicle is parked, and in particular when unoccupied. This operating mode can be a post-conditioning heating mode.

[0081] According to another option of the invention, a user can trigger preconditioning. Before using the motor vehicle, the user sends a command to process the first heat exchanger. The control unit 18 is adapted to receive the processing command, then to act on the circuit 16 by activating at least the compressor 34 and using the second heat exchanger 36 to heat the first heat exchanger 32 to a predefined temperature of at least 55°C, so as to eliminate all or part of the microorganisms that may be present in said first heat exchanger 32.

[0082] The control unit 18 is configured to operate over several temperature ranges, also considered as different vehicle operating ranges. In particular, the control unit 18 is adapted to trigger the heating of the first heat exchanger to at least 55°C when the outside temperature is below 12°C. Below this temperature, preconditioning can be carried out. Such preconditioning can be preprogrammed.

[0083] The control unit 18 is also adapted to trigger the heating of the first heat exchanger to at least 55°C when the outside temperature is within a temperature range. The temperature range extends from 12°C to 28°C. Within this temperature range, post-conditioning is performed.

[0084] The control unit 18 is further adapted to trigger the heating of the first heat exchanger at at least 55°C when the outside temperature is greater than or equal to 29°C. In this case, post-conditioning may be preferred. Thus, the invention extends the temperature range in which the heat pump system operates. Indeed, the heating function of the heat pump system is not necessary for the thermal comfort of the occupants when the temperature is greater than or equal to 29°C. However, the thermal efficiency of the heat pump system increases with temperature. Thus, the invention optimizes energy consumption.

[0085] Figure 3 shows a diagram of a disinfection process for a heat pump system. More generally, the process may be a heating process for a heat pump system. The heat pump system may be identical or similar to that shown in relation to Figure 1 and / or Figure 2.

[0086] The process comprises the following steps, preferably executed in the following order.

[0087] Heating 100 of the passenger compartment by the second heat exchanger.

[0088] Temperature rise of the first heat exchanger to 102.

[0089] Heating 104 of the first heat exchanger to the predefined temperature of at least 55°C by means of the compressor and the second heat exchanger in order to eliminate microorganisms in said first heat exchanger.

[0090] Heating 106 of the first heat exchanger to a second temperature higher than the predefined temperature.

[0091] In heating stage 100, the heat pump system operates in a first mode in which the heat transfer fluid absorbs heat from the environment as it passes through the first heat exchanger, and then transfers this heat to the passenger compartment as it circulates through the second heat exchanger. At this stage, the first and second fans rotate to force air circulation through the first and second heat exchangers, respectively. Heat exchange is more significant, as are the phase changes.

[0092] At the temperature rise stage 102, the first heat exchanger gradually increases in temperature. This temperature rise is achieved thanks to the calories transported by the heat transfer fluid. The rise is gradual in order to To preserve the thermal efficiency of the heat pump system, the temperature rise between the outside temperature, or the vehicle's ambient temperature, and the preset temperature lasts from 5 to 20 minutes. Extending the temperature rise time contributes to the elimination of microorganisms. Indeed, some microorganisms are eliminated before reaching the preset temperature. Thus, the temperature rise time according to the invention optimizes energy consumption and the effectiveness of reducing the presence of certain microorganisms.

[0093] In the heating stage 104 of the first heat exchanger, the heat pump system operates in a second mode. The first heat exchanger receives heat from the heat transfer fluid. The heat transfer fluid is heated by the pump, specifically by the second heat exchanger. The second fan is activated, and the first fan is stopped or operates at a lower speed than in the heating stage 100.

[0094] In the heating step 104 of the first heat exchanger to the predefined temperature, microorganisms such as Escherichia coli, Pseudomonas aeruginosa, or Staphylococcus aureus are eliminated. The temperature increase and maintenance have a lethal effect on these microorganisms.

[0095] In the heating step 106 of the first heat exchanger to the second temperature, the heat pump system operates in a third mode. When the heating step 104 of the first heat exchanger to the predefined temperature has not been performed for a predefined period, for example, two months, the process performs the heating step 106 of the first heat exchanger to the second temperature. The second temperature is higher than the first temperature, for example, by at least 10°C. According to one option of the invention, the heating step 106 of the first heat exchanger to the second temperature is longer than the heating step 104 of the first heat exchanger.

[0096] The heating step 106 of the first heat exchanger to the second temperature makes it possible to reinforce disinfection when it has not been carried out for a significant period of time.

[0097] Optionally, at the temperature rise stage 102 and / or the heating stage 104 of the first heat exchanger, the outside temperature is greater than or equal to 29°C. This operating mode deviates from a case where heating via the heat pump system is required.

Claims

Demands

1. Motor vehicle (10) heat pump system (14), the heat pump system (14) comprising: a circuit (16) with a first heat exchanger (32), a compressor (34) configured to compress a heat transfer fluid, a second heat exchanger (36), and an expansion valve (38); characterized in that the heat pump system (14) further comprises a control unit (18) which is configured to act on the circuit (16) by actuating at least the compressor (34) and using the second heat exchanger (36) to heat the first heat exchanger (32) to a predefined temperature of at least 55°C, so as to eliminate all or part of the microorganisms that may be present in said first heat exchanger (32).

2. Heat pump system (14) according to claim 1, characterized in that the first heat exchanger (32) is an evaporator; and / or in that the predefined temperature is between 60°C and 90°C; preferably between 65°C and 80°C.

3. Heat pump system (14) according to any one of claims 1 to 2, characterized in that the second heat exchanger is a condenser; and / or in that the heat pump system (14) further comprises a filter (40) associated with the first heat exchanger (32) defining a first zone (44) between said filter (40) and the first heat exchanger (32); the control unit (18) being configured to act on the circuit (16) in order to heat the first zone (44) to the predefined temperature.

4. Heat pump system (14) according to any one of claims 1 to 3, characterized in that the control unit (18) is configured to control the maintenance of the predefined temperature for a period of between 5 minutes and 20 minutes, and / or the expansion valve (38) is a pilot-operated expansion valve, and the control unit (18) is configured to control the pilot-operated expansion valve.

5. A heat pump system (14) according to any one of claims 1 to 4, characterized in that the first heat exchanger (32) comprises a first fan (46) and the second heat exchanger (36) comprises a second fan (48); the control unit (18) further configured to actuate the second fan (48) and to stop or slow down the first fan (46) in order to heat the first heat exchanger (32) at the predefined temperature.

6. Heat pump system (14) according to any one of claims 1 to 5, characterized in that the control unit (18) is configured to command a temperature rise from an ambient temperature to the predefined temperature, said temperature rise comprising a duration of between 10 minutes and 30 minutes, preferably between 15 minutes and 20 minutes.

7. Heat pump system (14) according to any one of claims 1 to 6, characterized in that the predefined temperature is a first temperature, and the control unit (18) is configured to calculate a first time between a given instant and a date of last heating of the first heat exchanger (32) to the first temperature, to compare the first time to a predefined time; and when the first time is greater than or equal to the predefined time, to heat the first heat exchanger (32) to a second temperature greater than the first temperature, by means of the compressor (34) and the second heat exchanger (36).

8. Motor vehicle (10) comprising a heat pump system (14), characterized in that the heat pump system (14) conforms to any one of claims 1 to 7, and the motor vehicle (10) comprises an electric battery system (20) for the propulsion of the motor vehicle (10), said electric battery system (20) being configured to power the heat pump system (14); preferably the first heat exchanger (32) comprises a first internal network with a first internal volume, and the second heat exchanger (36) comprises a second internal network with a second internal volume smaller than the first internal volume.

9. Motor vehicle (10) according to claim 8, characterized in that the motor vehicle (10) is capable of being connected to an external electrical power source so as to recharge the electric battery system (20), the control unit (18) being configured to heat the first heat exchanger (32) to the predefined temperature when the motor vehicle (10) is connected to the external power source.

10. A method for eliminating microorganisms in a heat pump system (14) for a motor vehicle (10) comprising a passenger compartment (12), characterized in that the heat pump system (14) conforms to any one of claims 1 to 7, and the method comprises the subsequent steps: heating (100) of the passenger compartment (12) by the second heat exchanger (36), then heating (104) of the first heat exchanger (32) to the predefined temperature of at least 55°C by means of the compressor (34) and the second heat exchanger (36) in order to eliminate microorganisms in said first heat exchanger (32).

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