METHOD FOR DEHUMIDIFYING A VEHICLE INTERIOR

Abstract

The present invention relates to a dehumidification method using a cooling fluid circuit (1) for vehicles, characterized in that the dehumidification method implements the following: - at least a first step in which, at a temperature of an internal air stream (28) at the outlet of a third heat exchanger (7) above a first temperature, a closing device (5) is brought into an open position, - at least a second step in which, at a temperature of the internal air stream (28) at the outlet of the third heat exchanger (7) below a second temperature, the closing device (5) is brought into a closed position, wherein the second temperature is lower than the first temperature.

Description

[0001] The field of the present invention is that of cooling fluid circuits for vehicles, in particular for hybrid or electric vehicles. The present invention relates in particular to dehumidification processes in which such cooling fluid circuits are used.

[0002] Motor vehicles are typically equipped with a cooling fluid circuit used to heat or cool various areas or components of the vehicle. It is particularly well known to use these cooling fluid circuits to cool an electrical storage device, such as a battery in a vehicle equipped with this circuit.

[0003] It is also known to use this cooling fluid circuit for the thermal treatment of an airflow directed into the vehicle interior. Such thermal treatment makes it possible to supply warm or cold air, depending on the user's preference, to raise or lower the temperature in the vehicle interior.

[0004] In further use of the cooling fluid circuit, the airflow is intended for dehumidifying the vehicle interior. "Dehumidification" refers to the cooling fluid circuit's ability to limit the water content in the air inside the vehicle. When humid air from the interior comes into contact with a cold surface, the water contained in the air condenses, forming a film of water droplets on the cold surfaces of the vehicle interior, particularly on the windows. This film of water forms fog, especially on the inner surfaces of the windshield and the side windows, and impairs the driver's view of the road or the rearview mirrors. This loss of visibility poses a significant risk to the safety of the vehicle occupants, particularly the risk of a collision with another vehicle.

[0005] It is known to use the refrigerant circuit to dry the airflow directed into the vehicle interior. A heating, ventilation, and air conditioning system, referred to as the "system" in the following description, typically includes a radiator and an evaporator, both involved in the thermal treatment of this airflow. The heat source for the radiator is a condenser, which is part of the refrigerant circuit. The radiator is thus a hot point in the refrigerant circuit, contributing to the increase in temperature of the airflow intended for the vehicle interior. The evaporator is a cold point in the refrigerant circuit, cooling the airflow and thereby condensing any moisture contained within it. This prevents fogging and ensures the desired thermal comfort for the vehicle occupants.

[0006] It is also known that low temperatures outside the vehicle interior impair the efficiency of the evaporator operation. For example, at outside temperatures near 5 °C, there is a risk of the evaporator becoming clogged because the water vapor in the air freezes upon contact with the evaporator, which has a surface temperature close to 0 °C. This risk of clogging limits the evaporator's usability.

[0007] Furthermore, if the temperature of the airflow at the evaporator inlet is low, particularly if it is below 12 °C, the evaporator reduces the pressure in a low-pressure section of the cooling fluid circuit. This low pressure is a limiting factor in the thermodynamic cycle, preventing sufficient heat from being generated on the condenser side, thus requiring an additional heat source to reach the desired temperature for the passenger compartment occupants.

[0008] The present invention proposes to overcome these various limitations by a method for dehumidifying a vehicle interior through which a cooling fluid flows and which comprises at least a primary circuit and a secondary circuit, wherein the primary circuit comprises at least a device for compressing the cooling fluid, a first heat exchanger designed to carry out heat exchange between the cooling fluid and a fluid, an expansion element, and a second heat exchanger designed to carry out heat exchange between the cooling fluid and an airflow outside the vehicle interior, wherein the secondary circuit is connected to the primary circuit in parallel to the second heat exchanger and the expansion element and comprises an expansion element and a third heat exchanger designed to carry out heat exchange between the cooling fluid and an interior airflow directed into the vehicle interior.is designed, wherein the secondary circuit has at least one closure device that can assume a closed position in which the circulation of the cooling fluid within the secondary circuit is prevented, and an open position that allows the circulation of the cooling fluid within the secondary circuit, wherein the primary circuit and the secondary circuit are simultaneously traversed by the cooling fluid, a method for dehumidifying a vehicle interior in which the expansion element and the expansion device carry out an expansion and the second heat exchanger and the third heat exchanger ensure the evaporation of the cooling fluid, characterized in that at an air temperature outside the interior which is below a first threshold value, the dehumidification method implements the following: - at least a first step, in which, when the temperature of the internal airflow at the outlet of the third heat exchanger is above a first temperature, the closing device is moved into its open position, - at least a second step in which, when the temperature of the internal airflow at the outlet of the third heat exchanger is below a second temperature, the closing device is moved into its closed position, the second temperature being below the first temperature.

[0009] The vehicle cooling fluid circuit comprises two circuit sections, referred to as the primary circuit and the secondary circuit. The primary circuit includes a compression device, a first heat exchanger, an expansion element, a second heat exchanger, and a cooling fluid reservoir. The secondary circuit includes an expansion element, a shut-off device, and a third heat exchanger. The cooling fluid circuit is designed so that this secondary circuit can be isolated from the rest of the circuit. This isolation of the secondary circuit is made possible by the shut-off device, which can assume two positions: an open position and a closed position. In its open position, the shut-off device allows the cooling fluid to circulate within the secondary circuit and, in particular, to reach the third heat exchanger.In the closed position of the shut-off device, the cooling fluid does not circulate in the secondary circuit, which is isolated from the main cooling fluid circuit. The open or closed position of the shut-off device depends on the temperature of the indoor airflow at the outlet of the third heat exchanger. This temperature reading at the outlet of the third heat exchanger is provided, for example, by a sensor located at the same level as the indoor airflow at the outlet of the third heat exchanger. If, for example, the outdoor air temperature is below 12 °C, preferably below 7 °C, and preferably between 5 °C and 7 °C, the method executes the first and second steps.During these steps, the shut-off device is in its open position when the temperature of the internal airflow at the outlet of the third heat exchanger is, for example, greater than or equal to 7 °C, while the shut-off device is in its closed position when the temperature of the internal airflow at the outlet of this third heat exchanger is, for example, less than or equal to 3 °C. The temperature of the internal airflow at the outlet of the third heat exchanger fluctuates between 3 °C and 7 °C, tending towards an average temperature of 5 °C in this example. The position of the shut-off device constitutes an opening and closing cycle of the shut-off device.It should be noted, firstly, that the temperature towards which the indoor airflow approaches the outlet of the third heat exchanger depends on the temperature range within which the indoor airflow fluctuates at the outlet of the third heat exchanger, and secondly, that the shut-off device remains in its open or closed position until it reaches the first or second temperature, depending on the position of the shut-off device. In another example, with an outdoor airflow of 5 °C, the shut-off device is in its closed position at 3 °C and in its open position at 3.8 °C.

[0010] According to a feature of the invention, the first heat exchanger increases the temperature of the interior airflow. It is understood that the first heat exchanger affects the temperature of the airflow by transferring heat to the interior airflow. This heat exchange can be carried out directly between the first heat exchanger and the interior airflow directed into the vehicle interior. This heat exchange can also be carried out indirectly, in which case an additional device, such as a radiator, performs a heat exchange with the first heat exchanger by means of a fluid that flows through the radiator and the first heat exchanger, and then transfers the heat from the first heat exchanger to the interior airflow directed into the vehicle interior.

[0011] According to an advantageous feature, the secondary circuit's shut-off device is an on / off valve. The cooling fluid circuit is divided into two circuits that diverge at a divergence point and converge at a convergence point to form two parallel circuit sections. The primary circuit forms a loop leading from the compression unit to the second heat exchanger, and the secondary circuit forms a loop leading from the divergence point to the convergence point. The secondary circuit includes a valve that is modulatable between two positions, open and closed, and is located between the divergence point and the third heat exchanger. This valve is an embodiment of the shut-off device that isolates the secondary circuit from the rest of the cooling fluid circuit.In its open position, the valve allows the coolant to circulate in the secondary circuit and feed the third heat exchanger, while in its closed position, this valve allows the secondary circuit to be isolated from the rest of the coolant circuit. Thus, in the closed position, the coolant circulates only in the primary circuit, whereas in the open position, the coolant circulates in both the primary and secondary circuits.

[0012] According to an advantageous feature, the expansion element also serves as the shut-off device. The expansion element can allow or prevent the circulation of the cooling fluid in the third heat exchanger of the cooling fluid circuit. Advantageously, the expansion element can communicate with a device to modulate the access of the cooling fluid to the third heat exchanger according to the temperature of the internal airflow. When the expansion element also serves as the shut-off device, it performs the functions of expanding the cooling fluid and controlling the flow of the cooling fluid to the third heat exchanger.

[0013] According to a feature of the invention, the compression device regulates the temperature of the interior airflow by adjusting its rotational speed. It is understood that the rotational speed of the compression device can be adjusted in response to a setpoint specified by the vehicle user in order to change the temperature of the interior airflow directed into the vehicle interior.

[0014] According to an advantageous feature, the closing device is brought into its open position when the temperature of the internal airflow at the outlet of the third heat exchanger changes from the first temperature to the second temperature.

[0015] According to a further advantageous feature, the closing device is moved into its closed position when the temperature of the internal airflow at the outlet of the third heat exchanger transitions from the second temperature to the first temperature. A temperature sensor, located at the level of the airflow at the outlet of the third heat exchanger, controls the closing device, at least indirectly, such that as soon as the temperature of the internal airflow at the outlet of the third heat exchanger reaches the second temperature, which is, for example, less than or equal to 3 °C, the closing device is designed to move into its closed position. The closing device then remains in this closed position as long as the temperature of the internal airflow at the outlet of the third heat exchanger is, for example, below 7 °C.The same temperature sensor controls the shut-off device, at least indirectly, such that the shut-off device is designed to move to its open position as soon as the temperature of the internal airflow at the outlet of the third heat exchanger reaches the first temperature, which is, for example, greater than or equal to 7 °C. The shut-off device then remains in this open position as long as the temperature of the internal airflow at the outlet of the third heat exchanger is, for example, above 3 °C.

[0016] According to a feature of the invention, the closing device of the secondary circuit alternately moves between an open and a closed position according to a periodic phenomenon, thereby forming an opening and closing cycle of the closing device. The open or closed position of the closing device depends on the temperature of the internal airflow at the outlet of the third heat exchanger. The closing device transitions from its closed position to its open position when the temperature of the internal airflow at the outlet of the third heat exchanger is, for example, at least 7 °C. Similarly, the closing device transitions from its open position to its closed position when the temperature of the internal airflow at the outlet of the third heat exchanger is, for example, less than or equal to 3 °C.The temperature drop from 7 °C to 3 °C and the subsequent increase from 3 °C to 7 °C of the internal airflow at the outlet of the third heat exchanger occur within essentially identical time intervals. This temperature fluctuation of the internal airflow at the outlet of the third heat exchanger is a periodic phenomenon in which the number of changes of the closing device from its open to its closed position per unit of time remains approximately the same.

[0017] According to a further feature of the invention, the opening and closing cycle of the locking device occurs at a frequency of less than three cycles per minute. This frequency corresponds to the number of times the locking device performs an opening and closing cycle within a specific unit of time. A cycle is defined as the transition of the locking device from an initial position to an intermediate position and then back to its initial position.

[0018] According to a feature of the invention, the temperature of the interior airflow at the outlet of the third heat exchanger is measured by at least one sensor installed at the level of the interior airflow at the outlet of the third heat exchanger. Using the method for dehumidifying the vehicle interior, the temperature of the interior airflow at the outlet of the third heat exchanger can be controlled so that this temperature fluctuates between the first and second temperatures. This sensor thus communicates directly or indirectly with the shut-off device, thereby controlling the supply of coolant to the third heat exchanger so that the temperature of the coolant at the outlet of the third heat exchanger fluctuates between the first and second temperatures.

[0019] According to a further feature of the invention, the first threshold is a temperature between 5 °C and 12 °C. If the temperature of the air outside the vehicle interior is below 12 °C, there is a risk that the third heat exchanger will ice up during prolonged operation. This risk can be avoided with the dehumidification process.

[0020] According to an advantageous feature, the cooling fluid circuit includes a device for storing the cooling fluid.

[0021] According to a further feature of the invention, the second heat exchanger thermodynamically contributes to increasing the temperature of the indoor airflow by utilizing the heat absorbed from the outdoor airflow. The second heat exchanger behaves like an evaporator and acts as a cold point in the cooling fluid circuit, recovering heat from the outdoor airflow. According to the principles of thermodynamics, this heat contributes to increasing the temperature of the hot point in the cooling fluid circuit, which is the first heat exchanger. Increasing the temperature of the first heat exchanger facilitates increasing the temperature of the indoor airflow. Thus, the second heat exchanger indirectly contributes to increasing the temperature of the indoor airflow.

[0022] The present invention also relates to a cooling fluid circuit comprising at least one primary circuit and at least one secondary circuit, wherein the primary circuit comprises at least one compression device, a first heat exchanger, an expansion element and a second heat exchanger, and the secondary circuit is connected to the primary circuit in parallel to the second heat exchanger and the expansion element and comprises an expansion element and a third heat exchanger as well as at least one closure device which can assume a closed position in which the circulation of the cooling fluid within the secondary circuit is prevented and an open position in which the circulation of the cooling fluid within the secondary circuit is permitted.The primary circuit and the secondary circuit are simultaneously traversed by the cooling fluid, with the closure device in its open position, characterized in that the cooling fluid circuit implements the dehumidification process, wherein the closure device is designed to be actuated cyclically.

[0023] Further features and advantages of the invention will become apparent from the following description and from several exemplary embodiments, which are shown by way of example and without limitation with reference to the accompanying schematic drawings. These show: Fig. 1 a schematic representation of a cooling fluid circuit in which the dehumidification method according to the invention is implemented. Fig. 2 a schematic representation of a variant of the cooling fluid circuit in which the dehumidification process according to the invention is implemented, wherein the first heat exchanger is integrated directly into the system. Fig. 3 A schematic representation of the cooling fluid circuit in an operating mode that ensures cooling of the vehicle interior. Fig. 4 A schematic representation of the cooling fluid circuit in an operating mode that ensures the heating of the vehicle interior. Fig. 5 A schematic representation of the cooling fluid circuit in an operating mode that ensures dehumidification of the vehicle interior. Fig. 6 a graphical representation of the temperature profile of the interior airflow at the outlet of the third heat exchanger as a function of time when the cooling fluid circuit is used in an operating mode that ensures dehumidification of the vehicle interior. Fig. 7 a graphical representation of the temperature profile of the interior airflow at the radiator outlet as a function of time when the cooling fluid circuit is used in an operating mode that ensures dehumidification of the vehicle interior.

[0024] The terms "upstream" and "downstream" used in the following description refer to the direction of circulation of the fluid in question, i.e., the cooling fluid or the internal airflow. The cooling fluid is symbolized by an arrow indicating its direction of circulation in the relevant pipe. In the Fig. 3, Fig. 4 to Fig. In Figure 5, the solid lines show a section of the circuit in which the cooling fluid circulates, while the dashed lines show a section of the cooling fluid circuit in which the cooling fluid does not circulate. Fig. 3, Fig. 4 to Fig. In section 5, the open position of the valves is represented by a solid white fill, and the closed position by a solid black fill. If a valve is in its open position at one point during the operation of the cooling fluid circuit and in its closed position at another point in time, this valve is represented by a mixed black and white fill.

[0025] Fig. Figure 1 shows a cooling fluid circuit 1 with a primary circuit 25, a secondary circuit 24, and a branch 26, in which a cooling fluid circulates. The secondary circuit 24, the primary circuit 25, and the branch 26 are arranged such that the cooling fluid circuit 1 is a closed loop in which a thermodynamic cycle takes place.

[0026] The primary circuit 25 and the secondary circuit 24 separate at a divergence point 14 and converge again at a convergence point 15, so that between the divergence point 14 and the convergence point 15 the secondary circuit 24 and the primary circuit 25 are connected in parallel.

[0027] The primary circuit 25 is defined, according to the direction of circulation of the cooling fluid in this primary circuit 25, from an outlet port 92 of a compression device 9 to an inlet port 91 of the compression device 9. In the illustrated embodiment, the compression device 9 is an electric compressor with fixed piston displacement and variable speed. This compression device 9 is designed to compress the cooling fluid entering through the inlet port 91 at low pressure. This compression of the cooling fluid releases a cooling fluid at high pressure through the outlet port 92 of the compression device. Due to the thermodynamic principles applied in the cooling fluid circuit 1, heat is generated by the transition of the cooling fluid from the gaseous state at the outlet of the compression device 9 to the liquid state at the outlet of a first heat exchanger 2.The volume of the high-pressure cooling fluid at the outlet of the compression device 9 depends on the compression speed of this compression device 9. The higher the rotational speed of the compression device 9, the more heat is generated by the cooling fluid circuit 1. Thus, it is possible to control the heat output of the cooling fluid circuit 1 by adjusting the rotational speed of this compression device 9.

[0028] The cooling fluid exiting the compression device 9 and under high pressure circulates through the first heat exchanger 2, which in the illustrated embodiment is a condenser, i.e., a heat exchanger in which the cooling fluid condenses. The first heat exchanger 2 performs a heat exchange with a fluid that is in the Fig. In the embodiment shown in Figure 1, a heat transfer fluid circulates in a heat transfer fluid loop 200. The heat generated during the change of state of the cooling fluid, which is under high pressure, is transferred to the heat transfer fluid of the heat transfer fluid loop 200 at this first heat exchanger 2.

[0029] In this way, this heat transfer fluid transports the heat from the first heat exchanger 2 to a radiator 8 located in the system 20. The heat transfer fluid loop 200 comprises a first branch 21, through which the heat transfer fluid circulates from the first heat exchanger 2 to the radiator 8, and a second branch 29, through which the heat transfer fluid circulates from the radiator 8 back to the first heat exchanger 2. This heat transfer fluid loop 200 forms a closed loop, in which a pump 22 ensures the circulation of the heat transfer fluid within this heat transfer fluid loop 200.

[0030] In an alternative embodiment, this first heat exchanger 2 can be installed directly in the system 20. In this case, it is not necessary to set up the heat transfer fluid loop 200.

[0031] The cooling fluid, which has changed from a gaseous to a liquid state by condensation in the first heat exchanger 2, flows through a storage device 4, which in the illustrated embodiment is a filter-dryer designed to remove moisture and fine particles present in the cooling fluid. It should be noted that this filter-dryer can advantageously be integrated into the first heat exchanger 2.

[0032] At the outlet of the storage device 4, the cooling fluid reaches the divergence point 14. At this divergence point 14, the cooling fluid can enter the secondary circuit 24 and / or reach an expansion element 12. This expansion element 12 is located upstream of a second heat exchanger 13. This expansion element 12 can advantageously be electrically controlled and actuated electrically or electronically. Thus, the expansion element 12 can be in an open position to allow the flow of the cooling fluid to the second heat exchanger 13, or in a closed position to prevent this. This expansion element 12 can also assume all intermediate positions to generate an expansion of the cooling fluid, i.e., to reduce the pressure of the cooling fluid. It should be noted that this expansion element 12 can be thermodynamically neutral, i.e.,The expansion element 12 can be an element of the cooling fluid circuit 1 that does not interfere with the thermodynamic cycle, especially when it is maximally open and does not cause any pressure loss.

[0033] The coolant at the outlet of the expansion element 12 enters the second heat exchanger 13, which in the illustrated embodiment is an evaporator-condenser located at the front of the vehicle. When the coolant at the outlet of the expansion element 12 is under low pressure, i.e., when the expansion element 12 has caused the high-pressure coolant to expand, the second heat exchanger 13 behaves like an evaporator. When the coolant at the outlet of the expansion element 12 is under high pressure, i.e., when the expansion element 12 is thermodynamically neutral, the second heat exchanger 13 behaves like a condenser. It should be noted that the second heat exchanger 13 is traversed by an airflow from outside the interior 27, which is directed towards the exterior of the interior. This airflow from outside the interior 27 is intended to facilitate heat exchange with the coolant.

[0034] The cooling fluid at the outlet of the second heat exchanger 13 reaches a first connection point 40, which is located downstream of the second heat exchanger 13 and at which the branch 26 is connected to the primary circuit 25.

[0035] This branch 26 extends from the first connection point 40 to a second connection point 41 located on the secondary circuit 24. Thus, the branch 26 allows the cooling fluid to flow from the primary circuit 25 to the secondary circuit 24. It should be noted that the branch 26 has a check valve that prevents the flow of cooling fluid from the secondary circuit 24 to the primary circuit 25 when the cooling fluid flows through the branch 26, particularly when cooling circuit 1 is performing the cooling function.

[0036] In the primary circuit 25, a first valve 11 is located downstream of the first connection point 40. This first valve 11 has two positions: an open and a closed position. In its open position, the first valve 11 allows the cooling fluid to flow through the primary circuit 25. In this open position, the cooling fluid does not flow through branch 26 due to the pressure difference between the secondary circuit 24 and the primary circuit 25. In its closed position, the first valve 11 prevents the cooling fluid from flowing through the primary circuit 25 beyond connection point 40. The cooling fluid then flows through branch 26 to reach the secondary circuit 24.When the expansion element 12 causes the cooling fluid to expand, the first valve 11 is advantageously in its open position, allowing the low-pressure cooling fluid to flow to the compression device 9 via the primary circuit 25. When the expansion element 12 is thermodynamically neutral, the cooling fluid at the outlet of the second heat exchanger 13 is under high pressure, the first valve 11 is then in its closed position, and the cooling fluid flows through the branch 26.

[0037] It should be noted that this first valve 11 is advantageously electrically controlled and is of the "on-off" type. Thus, when the expansion element 12 is thermodynamically neutral, the first valve 11 is in a closed position, while the first valve 11 is in its open position when the expansion element 12 causes an expansion of the cooling fluid.

[0038] The low-pressure cooling fluid downstream of the first valve 11 reaches the convergence point 15, where the secondary circuit 24 and the primary circuit 25 merge. The cooling fluid circuit includes a heat exchanger 16, which facilitates heat exchange between the low-pressure cooling fluid and the high-pressure cooling fluid. This heat exchange improves the performance of the thermodynamic cycle used in the cooling fluid circuit 1. Downstream of the convergence point 15, the primary circuit 25 opens into the compression device 9 and its inlet port 91.

[0039] The secondary circuit 24 extends from the divergence point 14 to the convergence point 15 and comprises an expansion element 6, a third heat exchanger 7, and a shut-off device 5, which in the illustrated embodiment is a second valve 5a. The second valve 5a is located between the divergence point 14 and the second connection point 41 and is advantageously electrically controlled and of the "on-off" type. The second valve 5a has two positions: an open position, in which the second valve 5a allows the high-pressure cooling fluid to flow through the secondary circuit 24, and a closed position, in which the second valve 5a prevents the high-pressure cooling fluid from flowing through the secondary circuit 24.

[0040] The expansion device 6, located downstream of the second valve 5a between the second connection point 41 and the third heat exchanger 7, is a component of the secondary circuit 24 that can cause expansion of the cooling fluid, i.e., reduce the pressure of the cooling fluid. This expansion of the high-pressure cooling fluid contributes to its evaporation in the second heat exchanger 7. Due to the thermodynamic principles applied in the cooling fluid circuit 1, cooling energy is generated by the transition of the cooling fluid from the liquid state at the outlet of the first heat exchanger 2 to the gaseous state at the outlet of the third heat exchanger 7.

[0041] It should be noted that in an alternative embodiment of the invention, the expansion element 6 can be the closure device 5. In this case, the closure device 5 ensures the expansion of the cooling fluid and modulates the flow of the cooling fluid to the third heat exchanger 7.

[0042] The system 20 comprises the heating element 8 and the third heat exchanger 7, which, in the illustrated embodiment, is used as an evaporator. An interior airflow 28, originating from outside or inside the vehicle interior, flows through the heating element 8 and the third heat exchanger 7. Thus, heat exchange takes place within this system 20 between the interior airflow 28 on the one hand and the third heat exchanger 7 and the heating element 8 on the other. A temperature sensor 17, installed in the interior airflow 28 at the outlet of the third heat exchanger 7, measures the temperature of the interior airflow 28. This temperature data for the interior airflow 28 is transmitted to a control device, for example, a computer, to modulate the position of the second valve 5a.It should be noted that in an alternative embodiment, the computer can also transmit this data regarding the temperature of the internal airflow 28 to the sealing device 5. The low-pressure cooling fluid at the outlet of the third heat exchanger 7 enters the primary circuit 25 at the convergence point 15 upstream of the compression device 9.

[0043] Valves 11 and 5a modulate the coolant circuit, allowing the coolant to circulate between the primary circuit 25, the secondary circuit 24, and the branch 26. This adjustable coolant circulation enables the coolant circuit to perform various functions, particularly heating, cooling, and dehumidifying the vehicle interior.

[0044] Fig. Figure 2 shows a variant of the cooling fluid circuit 1, in which the first heat exchanger 2 is installed in the system 20 and performs a heat exchange with a fluid which, in the illustrated embodiment, is the internal airflow 28. This variant of the cooling fluid circuit 1 makes it possible to dispense with the heat transfer fluid loop 200.

[0045] Fig. Figure 3 shows the cooling fluid circuit 1, which performs the cooling function of the vehicle interior. In this configuration of the cooling fluid circuit 1, both the first valve 11 and the second valve 5a are in their closed position. In this configuration of the cooling fluid circuit 1, the cooling fluid circulates according to a circulation direction of the cooling fluid 30 in the primary circuit 25, in the branch 26 and in the secondary circuit 24. In this configuration Fig. In the embodiment of the cooling fluid circuit 1 shown in Figure 3, the expansion element 12 is thermodynamically neutral, and the second heat exchanger 13 is used as a condenser. The cooling fluid undergoes a single expansion at the expansion element 6. The interior airflow 28 performs a heat exchange with the third heat exchanger 7, so that the interior airflow 28 at the outlet of the system 20 lowers the temperature in the vehicle interior compared to the temperature outside the vehicle interior.

[0046] Fig. Figure 4 shows the coolant circuit 1, which provides the heating function for the vehicle interior. In this configuration of the coolant circuit 1, the first valve 11 is in its open position, while the second valve 5a is in its closed position. The coolant circulates in the primary circuit 25 and does not circulate in the secondary circuit 24 or in the branch 26. This coolant circulates in the coolant circuit 1 according to a circulation direction of the coolant 30, which runs from the compression device 9 to the second heat exchanger 13, which functions as an evaporator, and from this second heat exchanger 13 to the compression device 9. In this configuration of the second valve 5a, the coolant does not reach the third heat exchanger 7, which is not supplied with coolant and is therefore thermally neutral.Within the system 20, a heat exchange takes place between the indoor airflow 28 and the radiator 8, so that the indoor airflow 28 can increase the temperature inside compared to the temperature outside the indoor space. It should be noted that in the [unclear]... Fig. In the embodiment shown in Figure 4, the first heat exchanger 2 indirectly performs a heat exchange with the airflow 28 via the heat transfer fluid loop 200.

[0047] Fig. Figure 5 shows the cooling fluid circuit 1, which ensures the dehumidification of the vehicle interior, thereby resolving the icing problems of the third heat exchanger 7 and providing heating of the interior airflow 28. In the Fig. In the embodiment shown in Figure 5, the cooling fluid circulates in parallel in the primary circuit 25 and in the secondary circuit 24. The first valve 11 of the primary circuit 25 is in its open position, and the expansion element 12 generates an expansion of the high-pressure cooling fluid originating from the first heat exchanger 2, whereby the third heat exchanger 13 then acts like an evaporator.

[0048] According to the method which is the subject of the invention, the second valve 5a is alternately in its open position, in which the third heat exchanger 7 is supplied with cooling fluid, and in its closed position, in which the second valve 5a prevents the cooling fluid from reaching the third heat exchanger 7.

[0049] This change between the open and closed positions of the second valve 5a depends on the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7. The temperature sensor 17 transmits information about the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7 to a control device, for example, a computer, which controls the second valve 5a. The second valve 5a is designed to be in its closed position when the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7 is less than or equal to 3 °C in the illustrated embodiment, and to be in its open position when the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7 is greater than or equal to 7 °C in the illustrated embodiment.

[0050] It should be noted that when the second valve 5a transitions from its open to its closed position, i.e., when the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7 is less than or equal to 3 °C, the third heat exchanger 7 is no longer supplied with cooling fluid, and the temperature of the internal airflow 28 at the outlet of this third heat exchanger 7 gradually increases. Similarly, when the second valve 5a transitions from its closed to its open position, i.e., when the temperature of the internal airflow 28 at the outlet of the third heat exchanger 7 is greater than or equal to 7 °C, the third heat exchanger 7 is supplied with cooling fluid, and the temperature of the internal airflow 28 at the outlet of this third heat exchanger 7 gradually decreases.

[0051] By switching between the closed and open positions of the second valve 5a, the temperature of the internal air flow 28 at the outlet of the third heat exchanger 7 can thus be kept between approximately 3 °C and 7 °C without negatively affecting the thermodynamic cycle, which without the invention would lead to a reduction in the rotational speed of the compression device and thus to the impossibility of generating enough heat in the first heat exchanger 2 to ultimately heat the interior.

[0052] Furthermore, this switching between the closed and open positions of the second valve 5a allows the temperature of the radiator 8 to be kept sufficiently high to heat the indoor airflow 28 at the outlet of the third heat exchanger 7. This switching between the open and closed positions of the second valve 5a allows a high pressure to be maintained in the low-pressure section of the cooling fluid circuit 1. By maintaining a temperature of the third heat exchanger 7 between 3 °C and 7 °C, the pressure of the cooling fluid in the low-pressure section of the cooling fluid circuit 1 allows for the maintenance of a high rotational speed of the compression device 9. This rotational speed of the compression device 9 makes it possible to maintain a high degree of condensation at the first heat exchanger 2, which is suitable for heating the indoor airflow 28.

[0053] Fig. Figure 6 shows a first diagram 39, which depicts an initial profile of the temperature 31 of the indoor airflow 28 at the outlet of the third heat exchanger 7 as a function of time 35. When the cooling fluid circuit 1 is started up according to its dehumidification function at outside temperatures below a first threshold of 12 °C, the second valve 5a is in its open position, and the temperature 31 of the indoor airflow 28 gradually decreases until it reaches a second temperature T2, which in the illustrated embodiment is slightly less than or equal to 3 °C. When the temperature 31 of the indoor airflow 28 at the outlet of the third heat exchanger 7 reaches this second temperature T2, the second valve 5a moves to its closed position, and the temperature 31 of the indoor airflow 28 gradually increases until it reaches a first temperature T1, which in the illustrated embodiment is slightly greater than or equal to 7 °C.It should be noted that the temperatures T1 and T2 can be changed depending on the desired temperature in the third heat exchanger 7. For example, the temperatures T1 and T2 can be 3.8 °C and 3 °C respectively, so that the temperature in the third heat exchanger 7 fluctuates between 3 °C and 3.8 °C.

[0054] When the temperature 31 of the internal air flow 28 at the outlet of the third heat exchanger 7 reaches this first temperature T1, after having previously reached the second temperature T2, the second valve 5a switches to the open position, and the temperature 31 of the internal air flow 28 gradually decreases until it again reaches the second temperature T2. Such a cycle repeats itself over time 35 as soon as the conditions are met.

[0055] By switching between the open and closed positions of the second valve 5a, the temperature 31 of the internal air flow 28 at the outlet of the third heat exchanger 7 can fluctuate around a first target temperature 32, which in the illustrated embodiment is essentially 5 °C, according to a periodic phenomenon in which each period represents a similar unit of time.

[0056] Fig. Figure 7 shows a second diagram 42, which depicts the temperature 36 of the indoor airflow 28 at the outlet of the radiator 8 as a function of time 35. When the cooling fluid circuit 1 is started, the temperature 36 of the indoor airflow 28 at the outlet of the radiator 8 gradually increases according to its dehumidification function at outside temperatures below a first threshold value of between 9 °C and 11 °C, until it stabilizes around a second target temperature 45 desired by the user.

[0057] By switching between the open and closed positions of the second valve 5a, a rotational speed for the compression device 9 can thus be ensured that is higher than that which it would have achieved without the cycle method according to the invention.

[0058] The invention is of course not limited to the examples just described, and numerous adaptations can be made to these examples without leaving the scope of the invention.

[0059] The invention, as just described, achieves the intended objectives and makes it possible to propose a method for dehumidifying the vehicle interior by maintaining the temperature of the interior airflow at the system's outlet at a sufficiently high level to ensure the comfort of the vehicle occupants without requiring an additional heating system. Variations not described here could be implemented without deviation from the context of the invention, provided they include a dehumidification method according to the invention.

Claims

[1] Method for dehumidifying a vehicle interior using a vehicle cooling fluid circuit (1) through which a cooling fluid flows and which comprises at least a primary circuit (25) and a secondary circuit (24), wherein the primary circuit (25) comprises at least a device (9) for compressing the cooling fluid, a first heat exchanger (2) designed to carry out heat exchange between the cooling fluid and a fluid, an expansion element (12) and a second heat exchanger (13) designed to carry out heat exchange between the cooling fluid and an airflow (27) outside the vehicle interior, wherein the secondary circuit (24) is connected to the primary circuit (25) in parallel to the second heat exchanger (13) and the expansion element (12) and comprises an expansion element (6) and a third heat exchanger (7) designed to carry out heat exchange between the cooling fluid and an interior airflow (28),which is directed into the vehicle interior, wherein the secondary circuit (24) has at least one closure device (5) which can assume a closed position in which the circulation of the cooling fluid within the secondary circuit (24) is prevented, and an open position in which the circulation of the cooling fluid within the secondary circuit (24) is permitted, wherein the primary circuit (25) and the secondary circuit (24) are simultaneously traversed by the cooling fluid, a method for dehumidifying a vehicle interior in which the expansion element (12) and the expansion device (6) undergo expansion and the second heat exchanger (13) and the third heat exchanger (7) ensure the evaporation of the cooling fluid, , characterized by , that if the air temperature outside the interior is below a first threshold, the dehumidification process implements the following: - at least a first step, in which, when the temperature of the internal air flow (28) at the outlet of the third heat exchanger (7) is above a first temperature (T1), the closing device (5) is brought into its open position, - at least a second step in which, when the temperature of the internal air flow (28) at the outlet of the third heat exchanger (7) is below a second temperature (T2), the closing device (5) is brought into its closed position, the second temperature (T2) being below the first temperature (T1). [2] Method for dehumidifying a vehicle interior according to the preceding claim, characterized by , that the first heat exchanger (2) increases the temperature of the internal airflow (28). [3] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by , that the closing device (5) of the secondary circuit (24) is a valve (5a) of the type ‘on-off valve’. [4] Method for dehumidifying a vehicle interior according to one of claims 1 and 2, characterized by , that the expansion organ (6) is also the closure device (5). [5] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by , that the compression device (9) regulates the temperature of the internal air flow (28) by adjusting its rotational speed. [6] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by , that when the temperature (31) of the internal air flow (28) at the outlet of the third heat exchanger (7) changes from the first temperature (T1) to the second temperature (T2), the closing device (5) is brought into its open position. [7] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by, that when the temperature (31) of the internal air flow (28) at the outlet of the third heat exchanger (7) changes from the second temperature (T2) to the first temperature (T1), the closing device (5) is brought into its closed position. [8] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by , that the first threshold corresponds to a temperature between 5 °C and 12 °C. [9] Method for dehumidifying a vehicle interior according to any of the preceding claims, characterized by , that the opening and closing cycle of the locking device (5) occurs at a frequency of less than three cycles per minute. [10] Method for dehumidifying according to any one of the preceding claims, characterized by , that the second heat exchanger (13) thermodynamically contributes to increasing the temperature of the internal airflow (28) by utilizing the heat absorbed in the external airflow (27). [11] Cooling fluid circuit (1) with at least one primary circuit (25) and at least one secondary circuit (24), wherein the primary circuit (25) comprises at least one compression device (9), a first heat exchanger (2), an expansion element (12) and a second heat exchanger (13), wherein the secondary circuit (24) is connected to the primary circuit (25) in parallel to the second heat exchanger (13) and the expansion element (12) and comprises an expansion element (6) and a third heat exchanger (7) as well as at least one closure device (5) which can assume a closed position in which the circulation of the cooling fluid within the secondary circuit (24) is prevented and an open position in which the circulation of the cooling fluid within the secondary circuit (24) is permitted, wherein the primary circuit (25) and the secondary circuit (24) are simultaneously traversed by the cooling fluid, wherein the closure device (5) is in its open position,, characterized by , that the cooling fluid circuit (1) performs the dehumidification process according to one of the preceding claims, wherein the closure device (5) is designed to be actuated cyclically.

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