FR3071048A1 - METHOD FOR STARTING A REFRIGERANT FLUID CIRCUIT COMPRISING A LIQUID PUMP - Google Patents

Abstract

Method for starting a refrigerant circuit (100, 200, 300), comprising at least: - a first sub-circuit (120, 220, 320) in which at least one compressor (122, 222, 322) is arranged a first heat exchanger (124, 224, 324) and a first expansion member (126, 226, 326); a second sub-circuit (140, 240, 340) in which at least one second trigger (142, 242, 342), a second heat exchanger (144, 244, 344) associated with a vehicle traction chain and a pump (146, 246, 346), - a third heat exchanger (162, 262). , 362) common to the first sub-circuit (120, 220, 320) and the second sub-circuit (140, 240, 340), the starting method comprising at least one initial step of stopping the pump (146, 246 , 346) and compressor (122, 222, 322), and a step of starting the compressor (122, 222, 322) for less than 2 minutes. Application to motor vehicles.

Description

METHOD FOR STARTING A REFRIGERANT FLUID CIRCUIT COMPRISING A LIQUID PUMP

The field of the present invention is that of refrigerant circuits for an installation for cooling an engine or a traction chain of a vehicle powered at least in part electric.

A motor vehicle is commonly equipped with a thermodynamic system allowing it to cool its engine and modify the aeraulic conditions inside its cabin. This thermodynamic system works through two circuits, one where a coolant circulates, the other where a coolant circulates. In each of the circuits, there are one or more heat exchangers, brought to transfer calories between induced air and the fluids circulating within the circuits. The refrigerant circuit allows the temperature of the air inside the passenger compartment to be modified, the coolant circuit having the objective of reducing the temperature of the engine. These circuits are either independent or connected to each other by a common heat exchanger. Most elements of the thermodynamic system are installed in the engine compartment of the vehicle.

Whichever configuration is chosen, the efficiency of the system is limited by the amount of air that can circulate through the various heat exchangers making up the system. Due to the number of heat exchangers included in each circuit, air can hardly circulate, which induces pressure losses and reduces the efficiency of the assembly.

One way to improve the efficiency of the system is to facilitate the passage of air within each element. One way to achieve this goal is to design a new architecture of the refrigerant circuit allowing the elimination of the coolant circuit. However, this new architecture does not make it possible to satisfactorily fulfill the intended objective. In fact, to operate, a pump in the refrigerant circuit must be supplied by the refrigerant in the liquid state. The refrigerant comprising too large a portion of gas within it causes cavitation by circulating within the pump, which prematurely wears out the pump. This premature wear causes breakdowns and therefore more frequent maintenance.

The invention fits into this context with the aim of ensuring the integrity of the pump, which is imperative for the viability of a system based on the elimination of the heat transfer fluid circuit. This removal reduces the number of elements installed in the engine compartment, improving the efficiency of the refrigerant circuit and thus the efficiency of the entire installation.

An object of the present invention is a method for starting a refrigerant circuit, comprising at least a first sub-circuit in which is arranged at least one compressor, a first heat exchanger and a first expansion member, a second sub-circuit in which is arranged at least a second expansion member, a second heat exchanger associated with a traction chain of the vehicle and a pump, and a third heat exchanger common to the first sub-circuit and to the second sub-circuit , the starting process comprising at least an initial step of stopping the pump and the compressor, and a step of starting the compressor for a duration of less than 2 minutes.

In a coolant circuit started according to the method of the invention, the pump is guaranteed to be supplied with coolant strictly in the liquid state, limiting or even eliminating the risks of wear and breakage by cavitation. In addition, the refrigerant circuit thus arranged makes it possible to dispense with the coolant circuit, and thus limit the number of elements. Limiting the number of elements simplifies the design and integration of the refrigerant circuit within the vehicle, while limiting its weight. As a result, air can circulate more easily within the engine compartment, the pressure drops are drastically reduced without affecting the system's efficiency and performance.

The method for starting the refrigerant circuit according to the invention advantageously comprises any one of the following characteristics, taken alone or in combination:

the method comprises an additional step of reducing the flow rate of an air flow passing through the third heat exchanger, the reduction in the flow rate of the air flow is effected by stopping a motor-fan unit of the third heat exchanger heat and / or by closing at least one flap arranged opposite the third heat exchanger, the additional step of reducing the air flow rate and the step of starting the compressor are simultaneous, the process includes an additional step of activating the pump, the additional step of activating the pump takes place after the end of the step of starting the compressor, the method comprises an additional step of activating the power unit fan of the third heat exchanger and / or opening of the flap arranged opposite the third heat exchanger, the additional step of activating the pump and the additional step of activ activation of the motor-fan unit of the third heat exchanger and / or of opening of the flap arranged opposite the third heat exchanger are simultaneous.

The invention also relates to a refrigerant circuit for a propulsion vehicle at least partly electric, comprising at least a first sub-circuit in which is arranged at least one compressor, a first heat exchanger and an expansion member, a second sub-circuit in which is arranged at least a second heat exchanger and a pump, and a third heat exchanger common to the first sub-circuit and to the second sub-circuit. The second heat exchanger is associated with a traction chain of the vehicle, and the compressor is configured to be started at start-up for a duration of less than 2 minutes.

It may be noted that the association of the second exchanger with a traction chain of the vehicle allows an exchange of calories between the refrigerant circulating in the second sub-circuit and an element of the traction chain of the vehicle, this exchange being done directly, or by means of a fluid caused to circulate in or around the element of the traction chain of the vehicle, this fluid can in particular be air, water or oil.

In accordance with what could have been specified previously, the threshold value given for the operating time of the compressor at startup makes it possible to supply the pump with coolant strictly in the liquid state.

The refrigerant circuit according to the invention advantageously comprises any one of the following characteristics, taken alone or in combination:

The pump is arranged to admit the refrigerant in the liquid or essentially liquid state. Essentially liquid means that the pump is arranged to admit the refrigerant comprising a gaseous fraction of less than 5% by volume of the refrigerant.

The pump is arranged upstream of the second heat exchanger, according to the direction of circulation of the coolant. In other words, the refrigerant leaving the pump circulates in the second heat exchanger. Alternatively or additionally, the refrigerant leaving the second heat exchanger cannot circulate in the pump.

The pump is of the hydraulic pump type. More particularly, the pump is chosen from a gear pump, a vane pump, a piston pump and a centrifugal pump.

The third heat exchanger is configured to heat the air flow passing through it. The third heat exchanger thus has the additional effect of cooling the refrigerant present in the third heat exchanger. The third heat exchanger is thus used as a condenser. In a variant of the invention, the third heat exchanger is arranged to operate according to the preceding description, as a condenser, or as an evaporator, that is to say that it is configured to cool the air flow passing through it . The third heat exchanger thus has the additional effect of heating the fluid present in the third heat exchanger.

The first heat exchanger is configured to cool the air flow passing through it. The first heat exchanger thus has the additional effect of heating the fluid present in the first heat exchanger. The first heat exchanger is thus used as an evaporator. The first heat exchanger can be for example a tube exchanger, a spiral exchanger or a plate exchanger.

The second heat exchanger is configured to cool the air flow passing through it. The second heat exchanger thus has the additional effect of heating the fluid present in the second heat exchanger. The second heat exchanger is thus used as a boiler. The second heat exchanger can be for example a tube exchanger, a spiral exchanger or a plate exchanger.

The circuit includes a third sub-circuit independent of the first sub-circuit and the second sub-circuit, the third sub-circuit comprising a fourth heat exchanger. The fourth heat exchanger is configured to heat the air flow passing through it. The fourth heat exchanger thus has the additional effect of cooling the refrigerant present in the fourth heat exchanger. The fourth heat exchanger is thus used as an internal condenser, that is to say it is arranged so as to heat an air flow intended to be sent into the passenger compartment of the vehicle, according to the needs of the users of the vehicle. and the operating condition of the vehicle.

The circuit includes at least one expansion member.

The first sub-circuit comprises an accumulator, known as a “drying bottle”, arranged to retain a fraction of the refrigerant in the liquid state, to prevent deterioration of the compressor by the fluid in the liquid state, and arranged to retain the molecules any water present in the refrigerant circuit.

The compressor is an electric compressor. An electric compressor includes an electric motor driving a compression device. In a variant of the invention, the electric motor and the compression device are arranged in a common housing.

At least one expansion member is controlled, for example electronically, to pass the coolant from a first pressure to a second pressure lower than the first pressure.

The invention also relates to a vehicle equipped with the refrigerant circuit as described above.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below by way of indication in relation to the drawings in which FIG. 1 is a diagrammatic illustration of a refrigerant circuit according to a first embodiment of the invention, Figure 2 is a schematic illustration of a refrigerant circuit according to a second embodiment of the invention, Figure 3 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a first operating mode, FIG. 4 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a second operating mode, FIG. 5 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a three isth operating mode, FIG. 6 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a fourth operating mode, FIG. 7 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a fifth operating mode, FIG. 8 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a sixth operating mode, FIG. 9 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a seventh mode of operation, FIG. 10 is a schematic illustration of the refrigerant circuit according to the second embodiment of the invention, in a eighth operating mode, FIG. 11 is a schematic illustration of a circuit of refrigerant according to a third embodiment of the invention, Figure 12 is a schematic illustration of the refrigerant circuit according to the third embodiment of the invention, in a first mode of operation, Figure 13 is an illustration schematic of the refrigerant circuit according to the third embodiment of the invention, in a second mode of operation, FIG. 14 is a schematic illustration of the refrigerant circuit according to the third embodiment of the invention, in a third operating mode, Figure 15 is a schematic illustration of a refrigerant circuit according to a fourth embodiment of the invention, Figure 16 is a schematic illustration of the refrigerant circuit according to the fourth embodiment of the invention, in a first operating mode, FIG. 17 is a diagrammatic illustration ic of the refrigerant circuit according to the fourth embodiment of the invention, in a second mode of operation, FIG. 18 is a schematic illustration of the refrigerant circuit according to the fourth embodiment of the invention, in a third operating mode, FIG. 19 is a schematic illustration of the refrigerant circuit according to the fourth embodiment of the invention, in a fourth operating mode.

it should first be noted that the figures show the invention in detail to implement the invention, said figures can of course be used to better define the invention, if necessary.

In the following description, the terms upstream and downstream are used to describe the arrangement of a component with respect to the direction of circulation of a fluid considered. Similarly, the arrangement of the constituent elements of a circuit of a fluid is given with respect to the direction of circulation of this fluid in the circuit.

An element described below as being located between two other elements does not mean that the element is physically between the other two, but that the fluid passes first through one of the two elements, before passing through the element considered.

In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter or even first criterion and second criterion etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria that are similar but not identical. This indexing does not imply a priority of an element, parameter or criterion over another and one can easily interchange such names without departing from the scope of this description. This indexing does not imply an order in time for example to assess this or that criterion.

Several architectures of the refrigerant circuit are possible. Four embodiments of the refrigerant circuit according to the invention are illustrated in FIGS. 1, 2, 11 and 15. These examples are in no way limiting, other embodiments being able to be envisaged in the spirit of the invention. 'invention.

Referring first to FIG. 1, there is seen a first example of arrangement of the circuit 100 of refrigerant fluid. This refrigerant circuit is composed of a first sub-circuit 120, a second sub-circuit 140 and a common part 160 to the first sub-circuit 120 and to the second sub-circuit 140.

The first sub-circuit 120 comprises a compressor 122, a first heat exchanger 124 and a first expansion member 126. The refrigerant circulates within the first sub-circuit 120 so as to pass successively through the first expansion member 126, the first heat exchanger 124 then the compressor 122.

The first heat exchanger 124 is a heat exchanger between the refrigerant which flows through it and an air flow. The first heat exchanger 124 is used as an evaporator, that is to say that it heats the refrigerant while cooling and drying the air flow. The refrigerant which circulates within the first sub-circuit 120, on leaving the first heat exchanger 124 and before passing into the compressor 122, is in gaseous form.

The first sub-circuit 120 further comprises a valve 128, arranged to authorize or prohibit the circulation of the refrigerant fluid within the first sub-circuit 120. The valve 128 is arranged upstream of the first expansion member 126, between the first member expansion valve 126 and the common part 160. This valve 128 is electronically controlled, for example by a central vehicle control unit. The first sub-circuit 120 also includes a first non-return valve 130 arranged upstream of the compressor 122, between the compressor 122 and the first heat exchanger 124 ·

The first non-return valve 130 is arranged to allow the coolant to flow in only one direction, thereby preventing the coolant from backflowing under the effect of pressure variations inside the circuit. The first non-return valve 130 is chosen from the usual types of non-return valves. The other non-return valves described below have the same function, and can be of the same type as the first non-return valve 130 or of a different type.

The second sub-circuit 140 comprises a second expansion member 142, a second heat exchanger 144 and a pump 146.

The second heat exchanger 144 is a heat exchanger between the refrigerant which flows through it and an air flow. The second heat exchanger 144 is associated with at least one element of the vehicle's electric motor. Such an element of the electric motor is an element of an electric traction chain of the vehicle, for example the electric propulsion motor of the vehicle and / or the power components supplying said motor and called for example power electronics module or else one or more vehicle batteries.

The second heat exchanger 144 is used as a cooler of the element of the electric motor, that is to say that it heats the refrigerant fluid while cooling the air flow caused to circulate thereafter around or in this element of the electric motor, thereby lowering its temperature. During its passage through the second heat exchanger 144, the refrigerant evaporates. The refrigerant leaving the second heat exchanger 144 is completely gaseous.

The pump 146 is a device arranged to suck the refrigerant circulating in the common part 160 and discharge it into the second sub-circuit 140 ·

The pump 146 is notably different from the compressor 122 in that it is arranged to operate at constant volume, where the compressor 122 compresses the fluid circulating within it and reduces the volume that this fluid occupies.

Another notable difference between the pump 146 and the compressor 122 is that the pump 146 is arranged to admit and treat a fluid in the liquid or essentially liquid state, that is to say a fluid comprising a gaseous portion of less than 5%. of the total volume of the fluid. A larger gaseous portion increases the risk of cavitation of the fluid during its passage through the pump 146, this cavitation causing premature wear of the pump 146 and, ultimately, the malfunction of the pump 146. By comparison, the compressor 122 is arranged to admit and treat a fluid in the gaseous or essentially gaseous state, that is to say a fluid comprising a liquid portion of less than 5% of the total volume of the fluid. A larger liquid portion increases the risk of breakage of the compressor 122, a fluid in the liquid state being impossible to compress for the architecture of the compressor 122 used.

Pump 146 is of the type of a hydraulic pump, and in particular a gear pump, a vane pump, a piston pump or a centrifugal pump. However, it will be understood that the invention is not limited by the type of pump chosen, another pump can be used without affecting the implementation of the invention.

The second sub-circuit 140 also includes a second non-return valve 148 arranged downstream of the second expansion member 142, between the second expansion member 142 and the common part 160.

The common part 160 to the first sub-circuit 120 and to the second sub-circuit 140 comprises a third heat exchanger 162. This third heat exchanger 162 is a heat exchanger between the refrigerant which flows through it and an air flow. The third heat exchanger 162 is used as a condenser, that is to say that the refrigerant which circulates there will transfer calories to the air flow, making it possible to generate heat from the refrigerant by transferring it to the flow d air channeled into this condenser.

The different elements and sub-circuits are connected to each other by pipes 102.

On the other hand, the motor vehicle comprises at least one motor-fan group 104 and / or at least one flap 106. The motor-fan group 104 and the flap 106 are arranged opposite the third heat exchanger 162, in a compartment vehicle engine. The motor-fan unit 104 and the flap 106 are not part of the refrigerant circuit 100 in the sense that they are not traversed by the refrigerant.

The motor-driven fan unit 104 is arranged opposite the third heat exchanger 162, either upstream in the case of a fan-type motor-fan unit, or downstream in the case of an aspirating motor-fan group, by relative to the direction of circulation of the air flow passing through the third heat exchanger 162. In the case described here, the fan unit 104 is arranged downstream of the third heat exchanger 162. The fan unit 104 is arranged to increase the flow rate of the air flow passing through the third heat exchanger 162.

The flap 106 is arranged opposite the third heat exchanger 162, upstream of the third heat exchanger 162 relative to the direction of circulation of the air flow passing through the third heat exchanger 162. The flap 106 is arranged to control the flow of the air flow passing through the third heat exchanger 162. In the closed position, the flap 106 blocks the circulation of the air flow. In the open position, the flap 106 authorizes the circulation of the air flow, and doses the flow rate of the air flow passing through the third heat exchanger 162.

The third heat exchanger 162, thus associated with at least one flap 106 for regulating air intake and with a motor-fan unit 104, is more particularly intended to be placed on the front face of the motor vehicle.

In this first example, the refrigerant circulating in the refrigerant circuit 100 borrows the common part 160, then circulates in the first sub-circuit 120 and / or the second sub-circuit 140 ·

During its circulation within the various parts of the circuit 100, the refrigerant changes state, passing from the liquid state to the gaseous state and vice versa. More particularly, the refrigerant circulates in the common part 160 upstream of the third heat exchanger 162 in gaseous form. During its passage through the third heat exchanger 162, the refrigerant is liquefied, and then circulates in the rest of the common part 160 in liquid form, before being directed into the first sub-circuit 120 and / or the second subcircuit 140.

In the first sub-circuit 120, the refrigerant circulates in liquid form before passing through the first expansion member 126. The refrigerant expanded by the first expansion member 126 sees its pressure decrease, and remains in the liquid state before to circulate in the first heat exchanger 124 · During its passage through the first heat exchanger 124, the refrigerant changes to the gaseous state. The refrigerant is then compressed by the compressor 122 and sent to the common part 160.

In the second sub-circuit 140, the refrigerant circulates in the pump 146 to be sent to the second heat exchanger 144 · The heat transfer undergone within the second heat exchanger 144 brings the refrigerant in a gaseous state at the outlet of the second heat exchanger 144 · The refrigerant in this gaseous state is then sent to the common part 160.

The starting method according to the invention applied to the first embodiment of the refrigerant circuit 100 is detailed below.

When the vehicle starts, the system is stopped. More particularly, the pump 146 and the compressor 122 are stopped, the refrigerant not circulating. Once the vehicle has started, the compressor 122 is started while the pump 146 remains inert. Activation of the compressor 122 circulates the coolant in the first sub-circuit 120 and in the common part 160, the pump 146 stopping preventing the circulation of the fluid in the second sub-circuit 140. This step of starting the compressor 122 lasts less than two minutes. Simultaneously with the start-up stage of the compressor 122, the motor-fan unit 104 is stopped, while the shutter 106 is closed, which drastically reduces or even blocks the flow of the air flow in the third heat exchanger 162 and therefore the heat exchange at the level of the common part 160. At the same time, the activation of the compressor 122, the stopping of the motor-fan unit 104 and the closing of the shutter 106 brings the refrigerant fluid passing through the third heat exchanger 162 to be sub-cooled, that is to say that the refrigerant is completely liquid, without gaseous fraction.

Once the start-up step of the compressor 122 is finished, the pump 146 is activated, passing the coolant through the second sub-circuit 140 · The coolant being in the sub-cooled liquid state at the outlet of the third heat exchanger, directly upstream of the pump 146, the risks of cavitation of the fluid within the pump 146 are limited or even eliminated. Additionally, the motor-driven fan assembly 104 is activated and the shutter 106 is open, allowing the circulation or the increase in the flow rate of the air flow within the third heat exchanger 162.

Thus started, the refrigerant circuit 100 is protected against the risks of cavitation which can harm the integrity of its pump 146.

In FIG. 2, we can see a second embodiment of the refrigerant circuit according to the invention, known as the second circuit 200.

The second refrigerant circuit 200 according to this example comprises a first sub-circuit 220, a second sub-circuit 240 and a common part 260. These various components include the same elements as the refrigerant circuit exposed in FIG. 1, certain additional elements adding to it.

Unless otherwise stated, an element described in the following examples is identical in function to the element with the same name and described in the first example.

In particular, the first sub-circuit 220 comprises a compressor 222, a first heat exchanger 224, a first expansion member 226, a first valve 228 and a first non-return valve 230.

The first sub-circuit 220 further comprises an accumulator 232, called a "drying bottle", arranged to retain a fraction of the refrigerant fluid in the liquid state, to prevent deterioration of the compressor 222 by fluid in the liquid state, and arranged to retain any water molecules present in the refrigerant circuit. The accumulator 232 is also arranged to fulfill the role of coolant reserve for the coolant circuit. This reserve is intended to manage the circulating mass of coolant within the coolant circuit. Thus, when the load of the heat treatment system is low, the mass of refrigerant circulating in the refrigerant circuit is low, the accumulator 232 is configured to store the excess refrigerant. The refrigerant reserve also makes it possible to compensate for any leaks that the system may experience.

In the direction of circulation of the fluid within this first sub-circuit 220, the first expansion member 226 is arranged upstream of the first heat exchanger 224 · The accumulator 232 is arranged downstream of the first heat exchanger 224 and upstream of the compressor 222. The first non-return valve 230 is arranged downstream of the compressor 222. The valve 228 is arranged downstream of the first non-return valve 230.

The first sub-circuit 220 also includes a bypass portion 234 · The bypass portion connects part of the first sub-circuit 220, between the first heat exchanger 224 and the accumulator 232, to another part of the first sub-circuit 220, downstream of the first valve 228. The bypass portion 234 comprises a second valve 236 arranged to allow or prohibit the passage of the refrigerant fluid through the bypass portion 234 ·

The second sub-circuit 240 comprises a second heat exchanger 244, a second expansion member 242, a pump 246 and a second non-return valve 248. In the direction of circulation of the fluid within this second sub-circuit 240, the second non-return valve 248 is arranged upstream of the pump 246. The second heat exchanger 244 is arranged downstream of the pump 246. The second expansion member 242 is arranged downstream of the second heat exchanger 244 ·

In accordance with the above, the second heat exchanger 244 is associated with an element of an electric traction chain of the vehicle, for example the electric propulsion motor of the vehicle and / or the power components supplying said motor and called by example power electronics module or one or more vehicle batteries.

The common part 260 comprises a third heat exchanger 262. As previously, the third heat exchanger 262 is here used as a condenser, that is to say that it cools the refrigerant by heat transfer to a ducted air flow through the third heat exchanger 262. In accordance with the above, the third heat exchanger is associated with at least one flap 106 for regulating the air intake and with a motor-fan unit 104 ·

The second circuit 200 differs from the first circuit 100 previously described in particular in that it comprises a third sub-circuit 280. The third sub-circuit 280 comprises a fourth heat exchanger 282, a third expansion member 284 and a fourth member detent 286. The third detent member 284 is arranged downstream of the fourth heat exchanger 282. The fourth detent member 286 is arranged downstream of the fourth heat exchanger 282. The third detent member 284 and the fourth detent member 286 are each arranged on an independent branch of the third sub-circuit 280. More particularly, the third expansion member 284 is disposed on a first branch 288 of the third sub-circuit 280, the fourth expansion member 286 being disposed on a second branch 290 of the third sub-circuit 280. The first branch 288 leads to the first sub-circuit 220, upstream of the prem ier expansion member 226, the second branch 290 leading to the second sub-circuit 240, between the pump 246 and the second heat exchanger 244 · The third sub-circuit 280 is on the other hand connected with the first sub-circuit 220 , between the first non-return valve 230 and the first valve 228.

The third expansion member 284 and the fourth expansion member 286 are arranged to allow or not the passage of the coolant through the third sub-circuit 280.

The third sub-circuit 280 and the elements which it comprises are arranged to make it possible to increase the thermal performance of the loop, in particular by faction of the fourth heat exchanger 282 which consists of an internal heat exchanger, intended to allow an exchange between two low and high pressure fluids, including the refrigerant flowing through the third sub-circuit 280.

Eight different operating modes, based on the second embodiment of the invention, are illustrated in FIGS. 3 to 10. These operating modes do not in any way limit the invention, some of these modes being able to be combined, and other operating modes can be added to those listed below.

For each of the modes exposed below, the description of the operation of the circuit is made from a starting point to a point of arrival. These starting and ending points are chosen arbitrarily, the refrigerant circulating within the circuit by forming a loop. Another pair of starting and finishing points can be chosen, without impacting the operation of the circuit. In addition, for each of the operating modes set out below, it is indicated whether use is made of the starting method which is the subject of the invention.

The first operating mode, illustrated in FIG. 3, makes it possible to reduce the temperature of the air located in the passenger compartment of the vehicle. To fulfill this role, the refrigerant circuit 200 is arranged as follows. In this case, the refrigerant circulates in the common part 260 and the first sub-circuit 220.

This first embodiment represents the operation of the refrigerant circuit 200 during the execution of the starting process according to the invention.

The refrigerant circulates in the common part 260 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 262. In the third heat exchanger 262, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 262 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 262, the refrigerant is in the liquid or essentially liquid state. At start-up, the pump 246 is stopped so that, the third expansion member 284 present in this embodiment being also closed, the coolant is directed to the first sub-circuit 220. The coolant passes through the first expansion member 226 and undergoes a pressure drop, passing from high pressure to low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 224, where it cools and dries the air flow circulating in this first heat exchanger 224 and intended to be directed to the passenger compartment of the vehicle.

As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 224 · The second valve 236 being closed, the refrigerant does not circulate in the bypass portion 234 but passes into the accumulator 232. The refrigerant is then directed in the compressor 222 and thus passes from a low pressure to a high pressure. The refrigerant then passes through the first non-return valve 230 and then the first valve 228 before restarting its circuit.

The second operating mode, illustrated in FIG. 4> allows the cooling of an element of an electric traction chain of the vehicle, for example the electric propulsion motor of the vehicle and / or the power components supplying said motor and called for example power electronics module or one or more vehicle batteries. To fulfill this role, the refrigerant circuit 200 is arranged as follows. In this case, the refrigerant circulates in the common part 260 and the second sub-circuit 240, in which is arranged the second heat exchanger 244 associated with this element of an electric traction chain of the vehicle.

This operating mode is most often used when the vehicle has been running for a certain time. However, under certain conditions, such as an extremely high ambient temperature, this operating mode can be used very early and, as such, can be preceded by the starting process according to the invention if the refrigerant is not sufficiently cooled.

The refrigerant circulates in the common part 260 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 262. In the third heat exchanger 262, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 262 in a space separate but adjacent to the space in which the refrigerant fluid circulates, which has the effect of cooling the refrigerant fluid and of heating the air flow. At the outlet of the third heat exchanger 262, the refrigerant is in the liquid or essentially liquid state. With the pump 246 activated, the first expansion member 226 and the third expansion member 284 being closed, the refrigerant is directed to the second sub-circuit 240.

In the second sub-circuit 240, the refrigerant passes through the second non-return valve 248 before being sucked in and then returned by the pump 246 towards the second heat exchanger 244 · The refrigerant circulates within the second heat exchanger 244, where it absorbs calories from the powertrain, which cools the powertrain while increasing the temperature of the refrigerant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 242 which is inactive and which therefore has no action on the pressure of the refrigerant which circulates within it. The refrigerant then circulates in the common part 260 and starts the circuit again.

The third operating mode, illustrated in Figure 5, allows the vehicle’s electric motor to cool while reducing the temperature of the air in the vehicle’s passenger compartment. To fulfill this role, the refrigerant circuit 200 is arranged as follows. In this case, the refrigerant circulates in the common part 260, the first sub-circuit 220 and the second sub-circuit 240.

This operating mode cannot be used at start-up, since the pump 246 is used in this operating mode. As such, the execution of the starting method according to the invention is triggered prior to the use of this operating mode.

The refrigerant circulates in the common part 260 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 262. In the third heat exchanger 262, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 262 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 262, the refrigerant is in the liquid or essentially liquid state.

With the pump 246 activated, the first expansion member 226 open and the third expansion member 284 closed, part of the refrigerant is directed to the first sub-circuit 220 while another part of the refrigerant is sent to the second 240.

In the first sub-circuit 220, the refrigerant passes through the first expansion member 226 and undergoes a pressure drop, passing from high pressure to low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 224, where it cools and dries the air flow circulating in the first heat exchanger 224 and intended to be directed towards the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 224 · The second valve 236 being closed, the refrigerant does not circulate in the bypass portion 234 but passes into the accumulator 232. The refrigerant is then directed in the compressor 222 and thus passes from low pressure to high pressure. The refrigerant then passes through the first non-return valve 230 and then the first valve 228 before being mixed with the part of the refrigerant circulating in the second sub-circuit 240 to restart its circuit.

In the second sub-circuit 240, the refrigerant passes through the second non-return valve 248 before being sucked in and then discharged by the pump 246 towards the second heat exchanger 244 · The refrigerant circulates within the second heat exchanger 244> where it absorbs calories from the powertrain, which cools the powertrain while increasing the temperature of the refrigerant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 242 which is inactive and which therefore has no action on the pressure of the refrigerant which circulates within it. The refrigerant is then collected in the common part 260 with the part of the refrigerant having circulated in the first sub-circuit 220 and starts the circuit again.

Figure 6 shows a fourth mode of operation. In this operating mode, the refrigerant circuit works like a heat pump. The starting method according to the invention is not necessary for the use of this operating mode.

The refrigerant circulates in the common part 260 in gaseous or essentially gaseous form, at a low pressure, for example 3 bars, in a direction opposite to that in which it circulated in the previous examples. In particular, the refrigerant circulates in the first heat exchanger 262, before being directed into the bypass portion 234 · In the first heat exchanger 262, the refrigerant absorbs calories from the air flow circulating in the first heat exchanger 262 in a separate space but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 262, the refrigerant is in the gaseous or essentially gaseous state. The first valve 228 being closed and the second valve 236 being open, the refrigerant circulates in the bypass portion 234 then in the accumulator 232. The refrigerant is then compressed by the compressor 222 to reach a high pressure, for example 21 bars, before being directed to the third subcircuit 280.

Within the third sub-circuit 280, the refrigerant circulates in the fourth heat exchanger 282, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 282. The refrigerant is thus cooled by its passage in the fourth heat exchanger 282. After its passage in the fourth heat exchanger 282, the third expansion member 284 being closed, the refrigerant circulates on the second branch 290 of the third sub-circuit 280. The refrigerant undergoes a trigger during its passage through the fourth trigger member 286, passing from high pressure to low pressure. The refrigerant is then collected in the common part 260 to restart the circuit.

The fifth mode of operation, illustrated in FIG. 7, allows the cooling of the electric motor and the heating of the passenger compartment of the vehicle by means of a heat pump mode, the evacuation of excessive heat being done by the fourth. heat exchanger 282. The starting method according to the invention is not necessary for the use of this operating mode.

The refrigerant circulates at the outlet of the accumulator 232, at a low pressure, for example 3 bars, before being compressed during its passage by the compressor 222, which causes it to pass from low pressure to a first high pressure , for example 21 bars. The refrigerant at the first high pressure then passes through the first non-return valve 230 before passing through the third sub-circuit 280, the first valve 228 being closed.

Within the third sub-circuit 280, the refrigerant circulates in the fourth heat exchanger 282, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 282. The refrigerant is thus cooled by its passage through the fourth heat exchanger 282. After its passage through the fourth heat exchanger 282, part of the refrigerant circulates on the first branch 288 of the third sub-circuit 280, another part of the refrigerant circulates on the second branch 290 of the third sub-circuit 280.

The part of the refrigerant circulating on the second branch 290 passes through the fourth expansion member 286 where it undergoes an expansion, passing from the first high pressure to the low pressure, before a portion of the refrigerant is directed into the part common 260 of the third sub-circuit 280, another portion being directed towards the first sub-circuit 220.

The portion of the coolant directed towards the common part 260 passes through the third heat exchanger 262. During its passage through the third heat exchanger 262, the coolant transfers calories to the air flow passing through the third heat exchanger 262 reverse. The air flow is heated while the refrigerant is cooled. On leaving the third heat exchanger 262, the refrigerant is collected with the part of the refrigerant circulating in the second sub-circuit 240, before being directed into the bypass portion 234, the first valve 228 being closed. The second valve 236 is open and authorizes the passage of the refrigerant fluid through the bypass portion 234 to join the first sub-circuit 220 and the portion of the refrigerant fluid which circulates there.

The portion of the refrigerant directed towards the first sub-circuit 220 passes through the first expansion member 226 without undergoing any pressure arrangement. The refrigerant then circulates in the first heat exchanger 224, where it cools and dries the air flow circulating in the first heat exchanger 224 and intended to be directed towards the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The coolant is then collected with the coolant flowing in the bypass portion 234, before being sent to the accumulator 232.

The part of the refrigerant circulating on the first branch 288 passes through the third expansion member 284 where it undergoes an expansion, passing from the first high pressure to a second high pressure, for example 18 bars. After passing through the fourth expansion member 286, the coolant is collected in the second sub-circuit 240. Within the second sub-circuit 240, the coolant passes through the second heat exchanger 244, where the coolant absorbs calories from the vehicle’s powertrain, which warms the refrigerant and cools the vehicle’s powertrain. After passing through the second heat exchanger 244, the refrigerant is expanded by its passage within the second expansion member 242. The refrigerant thus passes from the second high pressure to the low pressure, before joining the portion of the fluid. refrigerant circulating in the common part 260 and being together directed towards the bypass portion 234 The different portions and parts of the refrigerant are thus combined, and can resume the refrigerant circuit.

The sixth operating mode, illustrated in FIG. 8, is arranged to allow the cooling of the electric motor and the heating of the passenger compartment of the vehicle by means of a heat pump mode, the evacuation of excessive heat being effected. by the fourth heat exchanger 282. The starting method according to the invention is not necessary for the use of this operating mode.

The refrigerant circulates at the outlet of the accumulator 232, at a low pressure, for example 3 bars, before being compressed during its passage by the compressor 222, which causes it to pass from low pressure to a first high pressure , for example 21 bars. The refrigerant at the first high pressure then passes through the first non-return valve 230 before passing through the third sub-circuit 280, the first valve 228 being closed.

Within the third sub-circuit 280, the refrigerant circulates in the fourth heat exchanger 282, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 282. The refrigerant is thus cooled by its passage through the fourth heat exchanger 282. After its passage through the fourth heat exchanger 282, the refrigerant is directed to the first branch 288, the fourth expansion member 286 being closed. The refrigerant passes through the third expansion member 284 where it undergoes an expansion, passing from the first high pressure to a second high pressure, for example 18 bars. After passing through the third expansion member 284, the refrigerant is collected in the second sub-circuit 240 · Within the second sub-circuit 240, the refrigerant passes through the second heat exchanger 244> and after its passage in the second heat exchanger 244> the refrigerant is expanded by its passage within the second expansion member 242. The refrigerant thus passes from the second high pressure to the low pressure, before circulating in the common part 260.

Within the common part 260, the refrigerant passes through the third heat exchanger 262. The refrigerant absorbs calories from the air flow, cooling the air flow passing through the third heat exchanger 262. The refrigerant is also warmed up during its transfer.

On leaving the third heat exchanger 262, the refrigerant is directed to the first sub-circuit 220. The refrigerant flowing in the first sub-circuit 220 passes through the first expansion member 226 without undergoing a change in pressure. The refrigerant then circulates in the first heat exchanger 224, where it cools and dries the air flow circulating in the first heat exchanger 224 and intended to be directed to the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up.

After circulating in the first heat exchanger 224, the refrigerant is sent to the accumulator 232 and the compressor 222 to restart the circuit.

The seventh operating mode, illustrated in FIG. 9> makes it possible to cool the electric motor of the vehicle while using the heat dissipated by the motor to heat the air intended to be sent into the passenger compartment of the vehicle, the engine load being low . The starting method according to the invention is not necessary for the use of this operating mode.

The refrigerant circulates at the outlet of the accumulator 232, at a low pressure, for example 3 bars, before being compressed during its passage by the compressor 222, which causes it to pass from low pressure to high pressure, for example 21 bars. The refrigerant at high pressure then passes through the first non-return valve 230 before passing through the third sub-circuit 280, the first valve 228 being closed.

Within the third sub-circuit 280, the refrigerant circulates in the fourth heat exchanger 282, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 282. The refrigerant is thus cooled by its passage through the fourth heat exchanger 282. After its passage through the fourth heat exchanger 282, the refrigerant is directed to the first branch 288, the fourth expansion member 286 being closed. Passing through the first branch 288, the coolant circulates within the third expansion member 284 by undergoing expansion, passing from high pressure to low pressure, before circulating within the second sub-circuit 240. Within this second sub-circuit 240, the refrigerant passes through the second heat exchanger 244> where it absorbs calories from the traction chain of the vehicle, thus cooling the electric motor of the vehicle. The refrigerant through the second heat exchanger 244 is heated. On leaving the second heat exchanger 244> the refrigerant passes through the second expansion member 242 without undergoing expansion, before passing through the bypass portion 232, the first valve 228 being closed. The refrigerant is then directed to the accumulator 232 to restart the circuit.

The eighth operating mode, illustrated in FIG. 10, makes it possible to cool the electric motor of the vehicle while using the heat dissipated by the motor to heat the air intended to be sent into the passenger compartment of the vehicle, the engine load being very important. This is typically the case for a vehicle traveling on a high speed road such as a highway. If this operating mode is requested when the vehicle is started, it is preceded by the starting process according to the invention.

The refrigerant circulates at the outlet of the accumulator 232, at a low pressure, for example 3 bars, before being compressed during its passage by the compressor 222, which causes it to pass from low pressure to high pressure, for example 21 bars. The refrigerant at high pressure then passes through the first non-return valve 230 before passing through the third sub-circuit 280.

Within the third sub-circuit 280, the refrigerant circulates in the fourth heat exchanger 282, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 282. The refrigerant is thus cooled by its passage through the fourth heat exchanger 282. After its passage through the fourth heat exchanger 282, the refrigerant is directed to the second branch 290, the third expansion member 284 being closed. Passing through the second branch 290, the refrigerant circulates within the fourth expansion member 286 without undergoing expansion, the fourth expansion member 286 here being inactive. The first expansion member 226 being closed, part of the refrigerant passes through the second sub-circuit 240, another part of the refrigerant passes through the common part 260.

The part of the refrigerant passing through the second sub-circuit 240 passes through the second non-return valve 248 before being sucked in and then discharged by the pump 246 towards the second heat exchanger 244 · The refrigerant circulates within the second exchanger heat 244, where it absorbs calories from the vehicle's traction chain, which cools the vehicle's traction chain while increasing the temperature of the refrigerant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 242 which is inactive and which therefore has no action on the pressure of the refrigerant which circulates within it.

The part of the refrigerant passing through the common part 260 through the third heat exchanger 262.

At the outlet of the third heat exchanger 262, the part of the refrigerant circulating within the common part 260 is collected with the part of the refrigerant circulating within the second sub-circuit 240. A portion of the refrigerant is directed to the third sub-circuit 280 passing through the first valve 228, to restart the circuit. Another portion of the refrigerant is directed to the first sub-circuit 220 by the bypass portion 234, the second valve 236 being open. The portion of the coolant passing through the bypass portion 234 passes through the second valve 236, before passing through the accumulator 234 · The coolant then passes through the compressor 222. After passing through the compressor 222, the coolant is directed towards the third sub-circuit 280, to join the portion of refrigerant having passed through the first valve 228, before recommencing the circuit.

Alternatively, the second valve 236 can be closed. The coolant does not pass through the accumulator 232, the compressor 222 and the first non-return valve 230. In this alternative, it is the pump 246 which allows the circulation of the coolant within the circuit 200.

In Figure 11, we can see a third embodiment of the refrigerant circuit according to the invention, said third circuit 3θθ ·

The third 3θθ refrigerant circuit according to this example comprises a first sub-circuit 320, a second sub-circuit 34θ> a third sub-circuit 380 and a common part 360. These different components include the same elements as the refrigerant circuit exposed to Figure 2, some additional elements added to it.

Unless otherwise stated, an element described in the following examples is identical in function to the element with the same name and described in the first example.

The first sub-circuit 320 thus comprises a compressor 322, a first heat exchanger 324, a first expansion member 326, a first valve 328, a first non-return valve 330 and an accumulator 332. The first sub-circuit 320 also includes a bypass portion 334, arranged identically to the bypass portion 234 illustrated in FIG. 2, and comprising a second valve 336 arranged to authorize or prohibit the passage of the coolant by the bypass portion 334 ·

The first sub-circuit 320 of the third circuit 300 is different in particular in that it comprises a first part of an internal heat exchanger 364 · The internal heat exchanger 364 is arranged to allow heat exchange between the refrigerant at a first point in the circuit and the refrigerant at a second point in the circuit. The internal heat exchanger 364 therefore comprises a first inlet associated with a first outlet, and a second inlet associated with a second outlet. The internal heat exchanger 364 is thus arranged to decrease the temperature of the hottest fraction of the coolant, and to increase the temperature of the coolest fraction of the coolant, in spaces separated one of the other.

The second sub-circuit 340 comprises a second heat exchanger 344, a second expansion member 342, a pump 346 and a second non-return valve 348. The second sub-circuit 340 is arranged identically to the second sub-circuit 240 of the second refrigerant circuit presented in Figure 2.

The common part 360 includes a third heat exchanger 362. As previously, the third heat exchanger 362 is here used as a condenser, that is to say that it cools the refrigerant by heat transfer to a ducted air flow through the third heat exchanger 362.

The common part 360 of the third circuit 300 is different in particular in that it comprises the second part of the internal heat exchanger 364 mentioned above.

The third sub-circuit 380 comprises a fourth heat exchanger 382, a third expansion member 384 and a fourth expansion member 386. The third sub-circuit is arranged identically to the third sub-circuit 280 illustrated in FIG. 2.

Three additional operating modes, based on the third embodiment of the invention, are illustrated in FIGS. 12 to 14 · These operating modes in no way limit the invention, some of these modes being able to be combined, and other operating modes can be added to those listed below. In particular, the eight operating modes described above are applicable to the third circuit 3θθ ·

The first additional operating mode, illustrated in FIG. 12, makes it possible to lower the temperature inside the passenger compartment of the vehicle. This first additional operating mode is similar to the first operating mode illustrated in FIG. 3. As such, the first additional operating mode represents the organization of the third circuit 300 and the path of the coolant when using the starting process. specific to the invention.

The refrigerant circulates in the common part 360 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 362. In the third heat exchanger 362, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 362 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 362, the refrigerant is in the liquid or essentially liquid state. The coolant then passes through the internal heat exchanger 364 "where it transfers calories to the coolant passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364 ", the refrigerant from the third heat exchanger 362 is therefore sub-cooled totally liquid. The pump 346 being stopped and the third expansion member 384 being closed, the refrigerant is directed to the first sub-circuit 320. The refrigerant passes through the first expansion member 326 and undergoes a pressure drop from high pressure at low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 324, where it cools and dries the air flow circulating in the first heat exchanger 324 and intended to be directed to the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 324 · The second valve 336 being closed, the refrigerant does not circulate in the bypass portion 334 but passes into the accumulator 332. After passing through the 'accumulator 332, the refrigerant passes through the internal heat exchanger 364' where it absorbs calories from the refrigerant fluid passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364 ", the refrigerant coming from the accumulator 332 is completely gaseous. The refrigerant is then directed into the compressor 322 and thus passes from low pressure to high pressure. The refrigerant then passes through the first non-return valve 330 and then the first valve 328 before restarting its circuit.

The second additional operating mode, illustrated in FIG. 13, makes it possible to lower the temperature inside the passenger compartment of the vehicle while cooling the electric motor of the vehicle. This second additional operating mode is similar to the third operating mode illustrated in FIG. 5. This additional operating mode calling on the pump 346, it requires the prior execution of the starting process according to the invention, before its use, so as to prevent cavitation of the refrigerant fluid within the pump 346.

The refrigerant circulates in the common part 360 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 362. In the third heat exchanger 362, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 362 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 362, the refrigerant is in the liquid or essentially liquid state. At the outlet of the third heat exchanger 362, the refrigerant is in the liquid or essentially liquid state. The coolant then passes through the internal heat exchanger 364, where it transfers calories to the coolant passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364, the refrigerant from the third heat exchanger 362 is sub-cooled and therefore completely liquid.

With the pump 346 activated, the first expansion member 326 open and the third expansion member 384 closed, part of the refrigerant is directed to the first subcircuit 320 while another portion of the refrigerant is sent to the second subcircuit 340 .

In the first sub-circuit 320, the refrigerant passes through the first expansion member 326 and undergoes a pressure drop, passing from high pressure to low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 324, where it cools and dries the air flow circulating in the first heat exchanger 324 and intended to be directed to the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 324 · The second valve 336 being closed, the refrigerant does not circulate in the bypass portion 334 but passes into the accumulator 332. After passing through the accumulator 332, the refrigerant passes through the internal heat exchanger 364, where it absorbs calories from the refrigerant fluid passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364, the refrigerant coming from the accumulator 332 is completely gaseous. The refrigerant is then directed into the compressor 322 and thus passes from low pressure to high pressure. The refrigerant then passes through the first valve 328 and then the first non-return valve 330 before being mixed with the part of the refrigerant circulating in the second subcircuit 340 to start its circuit again.

In the second sub-circuit 340, the refrigerant passes through the second non-return valve 348 before being sucked in and then discharged by the pump 346 in the direction of the second heat exchanger 344 · The refrigerant circulates within the second heat exchanger 344, where it absorbs calories from the vehicle’s powertrain, which cools the vehicle’s powertrain while increasing the temperature of the refrigerant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 342 which is inactive and which therefore has no effect on the pressure of the refrigerant which circulates therein. The refrigerant is then collected in the common part 360 with the part of the refrigerant having circulated in the first sub-circuit 320 and starts the circuit again.

The third additional operating mode, illustrated in FIG. 14, makes it possible to lower the temperature inside the passenger compartment of the vehicle while heating the vehicle's electric motor. This operating mode allows the newly started electric motor to quickly go from a low temperature to an optimal operating temperature. This additional operating mode can be used when starting the vehicle, without going through the starting process according to the invention.

The refrigerant circulates in the first sub-circuit 320 in the gaseous state and at a low pressure, for example 3 bars. The refrigerant is compressed during its passage through the compressor 322, and passes to a high pressure, for example 21 bars. The refrigerant then passes through the first valve 328, before part of the refrigerant is sent to the common part 360 while another part of the refrigerant is sent to the second sub-circuit 340.

The refrigerant circulating in the common part 360 passes through the third heat exchanger 362. The flap 106 being closed, there is little or no exchange between the refrigerant circulating in the third heat exchanger 362 and the flow d air circulating in the third heat exchanger 362 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 362, the refrigerant is in the gaseous or essentially gaseous state. The coolant then passes through the internal heat exchanger 364, where it transfers calories to the coolant passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364, the refrigerant from the third heat exchanger 362 is sub-cooled and therefore completely liquid. The coolant is then directed to the first sub-circuit 320.

The refrigerant circulates in the second sub-circuit 340 in the opposite direction with respect to the different modes described above. The refrigerant passes through the second expansion member 342 without undergoing expansion. The refrigerant then circulates in the second heat exchanger 344> where it transfers calories to the traction chain of the vehicle, which heats the traction chain of the vehicle while lowering the temperature of the refrigerant. At the outlet of the second heat exchanger 344, the refrigerant is in the liquid or essentially liquid state. The coolant then circulates successively in the fourth expansion member 384 and in the third expansion member 382, before being directed to the first sub-circuit 320.

Within the first sub-circuit 320, the refrigerant undergoes expansion during its passage through the first expansion member 326, passing from high pressure to low pressure. The refrigerant is then passed through the first heat exchanger 324 · The refrigerant absorbs calories from the air flow passing through the first heat exchanger 324 · This absorption increases the temperature of the refrigerant and decreases that of the air flow intended to be sent into the passenger compartment of the vehicle. After passing through the first heat exchanger 324, the refrigerant is in the gaseous or essentially gaseous state, and is directed towards the accumulator 332. At the outlet of the accumulator 332, the refrigerant passes through the heat exchanger internal 364 "where it absorbs calories from the refrigerant passing through the internal heat exchanger 364 in the opposite direction. At the outlet of the internal heat exchanger 364 ", the refrigerant coming from the accumulator 332 is completely gaseous. The refrigerant is then compressed by the compressor 322 to restart the circuit.

In FIG. 15, a fourth embodiment of the refrigerant circuit according to the invention can be seen, known as the fourth circuit 400.

The fourth refrigerant circuit 4 circuit according to this example comprises a first sub-circuit 420, a second sub-circuit 440, a third sub-circuit 480 and a common part 460. These different components include the same elements as the refrigerant circuit exposed in FIG. 11, certain additional elements being added thereto.

Unless otherwise stated, an element described in the following examples is identical in function to the element with the same name and described in the first example.

The first sub-circuit 420 thus comprises a compressor 422, a first heat exchanger 424, a first expansion member 426, a first valve 428 and an accumulator 432. The first sub-circuit 420 also includes a bypass portion 434, arranged identically to the bypass portion 234 illustrated in FIG. 2, and comprising a second valve 436 arranged to authorize or prohibit the passage of the coolant by the bypass portion 434 · The first sub-circuit 420 of the fourth circuit 400 also includes a first part of an internal heat exchanger 464 "arranged in a similar way and to fulfill the same role as the internal heat exchanger 364 of the third circuit 3θθ ·

The second sub-circuit 440 comprises a second heat exchanger 444, a second expansion member 442 and a pump 446. The second sub-circuit 440 is arranged identically to the second sub-circuit 440 of the second refrigerant circuit presented to Figure 2, with the difference that it comprises a fifth heat exchanger 450, said subcooler issuer, arranged upstream of the pump 446, that is to say between the pump 446 and a point of the common part 460 located between the third heat exchanger 462 and the internal heat exchanger 464 ·

This fifth heat exchanger 450 is a heat exchanger between the refrigerant flowing through it and an air flow. The fifth heat exchanger 450 is used as a sub-cooler, that is, it cools the refrigerant while heating the air flow. The refrigerant which circulates within the fifth heat exchanger 450 is thus sub-cooled, that is to say that the refrigerant is completely liquid on leaving the fifth heat exchanger 450, so as to minimize risk of cavitation during its circulation in the pump 446.

The common part 460 includes a third heat exchanger 462. As previously, the third heat exchanger 462 is used here as a condenser, that is to say that it cools the refrigerant by heat transfer to a ducted air flow through the third heat exchanger 462. The common part 460 of the third circuit 300 also includes the second part of the internal heat exchanger 464 mentioned above.

The third subcircuit 480 comprises a fourth heat exchanger 482 and a third expansion member 484 · The third subcircuit 480 is different from the third subcircuit 280 illustrated in FIG. 2 in particular in that it only comprises one member trigger, the third trigger 484, arranged upstream of the first branch 488 and the second branch 49θ> and in that it comprises a non-return valve 448 disposed on the first branch 488. The first branch 488 opens out on the second 44θ sub-circuit. between the pump 446 and the second heat exchanger 444, the second branch 490 opening onto the first sub-circuit 420, downstream of the first expansion member 426.

Four additional operating modes, based on the fourth embodiment of the invention, are illustrated in FIGS. 16 to 19. These operating modes in no way limit the invention, some of these modes being able to be combined, and other operating modes can be added to those listed below. In particular, the eight operating modes described above are applicable to the third circuit 400.

The first additional operating mode, illustrated in FIG. 16, makes it possible to lower the temperature inside the cabin of the vehicle. This first additional operating mode is similar to the first operating mode illustrated in FIG. 3. As such, the first additional operating mode represents the organization of the third circuit 400 and the path of the coolant when the method is used. boot specific to the invention.

The refrigerant circulates in the common part 460 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 462. In the third heat exchanger 462, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 462 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 462, the refrigerant is in the liquid or essentially liquid state. The coolant then passes through the internal heat exchanger 464, where it transfers calories to the coolant passing through the internal heat exchanger 464 in the opposite direction. At the outlet of the internal heat exchanger 464, the refrigerant coming from the third heat exchanger 462 is therefore sub-cooled totally liquid. The pump 446 being stopped and the third expansion member 484 being closed, the refrigerant is directed to the first sub-circuit 420. The refrigerant passes through the first expansion member 426 and undergoes a pressure drop from high pressure at low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 424, where it cools and dries the air flow circulating in the first heat exchanger 424 and intended to be directed to the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 424 · The second valve 436 being closed, the refrigerant does not circulate in the bypass portion 434 but passes into the accumulator 432. After passing through the accumulator 432, the refrigerant passes through the internal heat exchanger 464, where it absorbs calories from the refrigerant fluid passing through the internal heat exchanger 464 in the opposite direction. At the outlet of the internal heat exchanger 464, the refrigerant coming from the accumulator 432 is completely gaseous. The refrigerant is then directed into the compressor 422 and thus passes from low pressure to high pressure. The refrigerant then crosses the first valve 428 before restarting its circuit.

The second additional operating mode, illustrated in FIG. 17, makes it possible to lower the temperature inside the passenger compartment of the vehicle while cooling the electric motor of the vehicle. This second additional operating mode is similar to the second additional operating mode illustrated in FIG. 13. This additional operating mode calling on the pump 446, it requires the prior execution of the starting method according to the invention, before its use. , so as to prevent cavitation of the refrigerant fluid within the pump 446.

The refrigerant circulates in the common part 460 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 462. In the third heat exchanger 462, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 462 in a space separate but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 462, the refrigerant is in the liquid or essentially liquid state. At the outlet of the third heat exchanger 462, the refrigerant is in the liquid or essentially liquid state.

Part of the refrigerant is then directed to the second sub-circuit 4-4-0, another part continuing to circulate in the common part 460, to the internal heat exchanger 464.

The part of the refrigerant continuing its circulation in the common part 460 then passes through the internal heat exchanger 464. where it transfers calories to the refrigerant passing through the internal heat exchanger 464 in the opposite direction. The refrigerant then circulates in the first sub-circuit 420.

In the first sub-circuit 420, the refrigerant passes through the first expansion member 426 and undergoes a pressure drop, passing from high pressure to low pressure, for example 3 bars. The refrigerant then circulates in the first heat exchanger 424, where it cools and dries the air flow circulating in the first heat exchanger 424 and intended to be directed towards the passenger compartment of the vehicle. As it cools and dries the air flow, the refrigerant heats up. The refrigerant is gaseous or essentially gaseous at its outlet from the first heat exchanger 424 · The second valve 436 being closed, the refrigerant does not circulate in the bypass portion 434 but passes into the accumulator 432. After passing through the accumulator 432, the coolant passes through the internal heat exchanger 464. where it absorbs calories from the coolant passing through the internal heat exchanger 464 in the opposite direction. At the outlet of the internal heat exchanger 464. the refrigerant from the accumulator 432 is completely gaseous. The refrigerant is then directed into the compressor 422 and thus passes from low pressure to high pressure. The refrigerant then crosses the first valve 428 before being mixed with the part of the refrigerant circulating in the second sub-circuit 440 to start its circuit again.

In the second sub-circuit 4-4-0, the part of the refrigerant passes through the fifth heat exchanger 450, where the refrigerant transfers calories to the air flow circulating in the fifth heat exchanger 450, which further lowers the temperature of the refrigerant. Thus, at the outlet of the fifth internal heat exchanger 45θ> the refrigerant is sub-cooled and therefore completely liquid. The refrigerant is then sucked in and then refluxed by the pump 446 in the direction of the second heat exchanger 444 · The refrigerant circulates within the second heat exchanger 444, where it absorbs calories from the traction chain of the vehicle, this which cools the drive train of the vehicle while increasing the temperature of the coolant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 442 which is inactive and which therefore has no effect on the pressure of the refrigerant which circulates therein. The refrigerant is then collected in the common part 460 with the part of the refrigerant having circulated in the first sub-circuit 420 and starts the circuit again.

Figure 18 shows a third additional mode of operation. In this operating mode, the refrigerant circuit works like a heat pump. The starting method according to the invention is not necessary for the use of this operating mode.

The refrigerant circulates in the common part 460 in gaseous or essentially gaseous form, at a low pressure, for example 3 bars, in a direction opposite to that in which it circulated in the previous examples. In particular, the refrigerant circulates in the first heat exchanger 462, before being directed into the bypass portion 434 · In the first heat exchanger 462, the refrigerant absorbs calories from the air flow circulating in the first heat exchanger 462 in a separate space but adjacent to the space where the refrigerant circulates. At the outlet of the third heat exchanger 462, the refrigerant is in the gaseous or essentially gaseous state. The first valve 428 being closed and the second valve 436 being open, the refrigerant circulates in the bypass portion 434 then in the accumulator 432. The refrigerant then passes through the internal heat exchanger 464, where the refrigerant passing by the part of the internal heat exchanger 464 disposed on the common part 460 and the fluid passing through the part of the internal heat exchanger 464 disposed on the first sub-circuit 420 performs little or no exchange , the two portions of the fluid being at low pressure.

The refrigerant is then compressed by the compressor 422 to reach a high pressure, for example 21 bars, before being directed to the third sub-circuit 480.

Within the third sub-circuit 480, the refrigerant circulates in the fourth heat exchanger 482, where the refrigerant transfers calories to the air flow circulating in the fourth heat exchanger 482. The refrigerant is thus cooled by its passage in the fourth heat exchanger 482. After its passage in the fourth heat exchanger 482, the refrigerant is expanded by its passage in the third expansion member 484. passing from high pressure to low pressure. The refrigerant is then collected in the common part 460 where it passes through the internal heat exchanger 464. Within the internal heat exchanger 464. the refrigerant does not perform any exchange, the two portions of the fluid being at low pressure. The refrigerant is then directed to the third heat exchanger 462 to restart the circuit.

Figure 19 shows a fourth additional mode of operation. In this operating mode, the refrigerant circuit operates as a heat pump, using pump 446 rather than the compressor 422 to ensure the circulation of the refrigerant in the fourth circuit 4θθ · This additional operating mode making call to the pump 446, it requires the prior execution of the starting method according to the invention, before its use, so as to prevent cavitation of the refrigerant fluid within the pump 446.

The refrigerant circulates in the common part 460 in gaseous or essentially gaseous form, at a high pressure, for example 21 bars, and circulates in the third heat exchanger 462. In the third heat exchanger 462, the refrigerant transfers calories to the air flow circulating in the third heat exchanger 462 in a space separate but adjacent to the space where the refrigerant circulates, which heats the air flow while cooling the refrigerant circulating in the third heat exchanger 462. At the outlet of the third heat exchanger 462, the refrigerant is in the liquid or essentially liquid state.

Part of the refrigerant is then directed to the second sub-circuit 44θ> another part continuing its circulation in the common part 460, to the internal heat exchanger 464.

The part of the refrigerant circulating in the second sub-circuit 440 passes through the fifth heat exchanger 45θ, where the refrigerant transfers calories to the air flow circulating in the fifth heat exchanger 45θ, which further lowers the temperature of the fluid refrigerant. Thus, at the outlet of the fifth internal heat exchanger 45θ, the refrigerant is sub-cooled and therefore completely liquid. The refrigerant is then sucked up and then discharged by the pump 446 towards the second heat exchanger 444 · The refrigerant circulates within the second heat exchanger 444, where it absorbs calories from the traction chain of the vehicle, this which cools the drive train of the vehicle while increasing the temperature of the coolant. At the outlet of the second heat exchanger, the refrigerant is in the gaseous, essentially gaseous or two-phase liquid-gaseous state. The refrigerant then passes through the second expansion member 442 which is inactive and which therefore has no effect on the pressure of the refrigerant which circulates therein. The refrigerant is then collected in the common part 460 with the part of the refrigerant having circulated in the third sub-circuit 480 to restart the circuit.

The part of the refrigerant continuing its circulation in the common part 460 then passes through the internal heat exchanger 464. The first expansion member 426 being closed, the refrigerant does not circulate in the first sub-circuit 420, and consequently not in the part of the internal heat exchanger 464 located in the first sub-circuit 420. The internal heat exchanger 464 is therefore inert, that is to say that no heat exchange takes place at the within it. The refrigerant is then directed to the third sub-circuit 480 by the first branch 488, before passing through the third expansion member 484. The third expansion member 484 being inert, the refrigerant does not undergo any pressure variation. The refrigerant then passes through the fourth heat exchanger 482, where it transfers calories to the air flow circulating in the fourth heat exchanger 482, which heats the air flow while cooling the refrigerant. The refrigerant is then through the first valve 428 before being collected in the common part 460 with the part of the refrigerant circulating in the second sub-circuit 440 to restart the circuit.

In the above description, the heat exchange between the refrigerant and the traction chain or one of its elements is done directly, that is to say that the exchange is done without an intermediary, for example by circulation of the coolant in contact with the traction chain or one of its elements. It will however be understood that there can be an indirect exchange between the traction chain or one of its elements and the refrigerant circulating in the second heat exchanger, that is to say an exchange via 'Another fluid, in particular air, water or oil, which would exchange simultaneously with the refrigerant on the one hand and with the traction chain or one of its elements on the other hand.

The refrigerant is a refrigerant or a mixture of refrigerant, of the family of hydrochlorofluorocarbons (HCLC), or hydrofluorocarbons (HLC). The refrigerant may in particular be R134a or 1234YL. The refrigerant can also be carbon dioxide known by the acronym R744 ·

The foregoing description clearly explains how the invention makes it possible to achieve the objectives which it has set for itself, and in particular to propose a method for starting a refrigerant fluid circuit making it possible in particular to prevent cavitation within the pump circuit liquid.

This configuration allows the same refrigerant to be used with two common loops leading to a common high pressure condenser. This arrangement makes it possible in particular to use the same fluid with two separate sub-circuits to arrive at a common heat exchanger operating as a high pressure condenser. The pressure losses caused by the various heat exchangers of the circuit are thus compensated by the pump, which makes it possible to limit the consumption of the system under certain conditions, in particular for cooling the electric motor of the vehicle.

Of course, various modifications can be made by those skilled in the art to the starting process which has just been described by way of nonlimiting example, as soon as a step of stopping the pump is implemented. and the compressor, and a step of starting the compressor for a duration of less than 2 minutes.

In any event, the invention cannot be limited to the embodiment specifically described in this document, and extends in particular to all equivalent means and to any technically operative combination of these means.

Claims (10)

1. Method for starting a refrigerant circuit (100, 200, 300), comprising at least: a first sub-circuit (120, 220, 320) in which is arranged at least one compressor (122, 222, 322), a first heat exchanger (124, 224, 324) and a first expansion member (126, 226 , 326), a second sub-circuit (140, 240, 340) in which is arranged at least a second expansion member (142, 242, 342), a second heat exchanger (144> 244 "344) associated with a vehicle traction chain and a pump (146, 246, 346), a third heat exchanger (162, 262, 362) common to the first sub-circuit (120, 220, 320) and to the second sub-circuit (140, 240, 340), the starting method comprising at least an initial step of stopping the pump (146, 246, 346) and the compressor (122, 222, 322), and a step of starting the compressor (122 , 222, 322) for a period of less than 2 minutes. 2. Starting method according to the preceding claim, comprising an additional step of reducing the flow rate of an air flow passing through the third heat exchanger (162, 262, 362). 3- Starting method according to the preceding claim, the reduction in the flow rate of the air flow being effected by stopping a motor-fan unit (104, 204, 304) arranged opposite the third heat exchanger (162, 262, 362) and / or by closing at least one flap (106, 206, 306) arranged opposite the third heat exchanger (162, 262, 362). 4. Starting method according to any one of claims 2 or 3> wherein the additional step of reducing the air flow rate and the step of starting the compressor (122, 222, 322) are simultaneous . 5- A method of starting any one of the preceding claims, comprising an additional step of activating the pump (146, 246, 346). 6. Starting method according to the preceding claim, wherein the additional step of activating the pump (146, 246, 346) takes place after the end of the step of starting the compressor (122, 222, 322 ). 7- Refrigerant circuit for vehicle powered at least partly electric, comprising at least: a first sub-circuit (120, 220, 320) in which is arranged at least one compressor (122, 222, 322), a first heat exchanger (124, 224, 324) and a first expansion member (126, 226 , 326), a second sub-circuit (140, 240, 340) in which is arranged at least a second expansion member (142, 242, 342), a second heat exchanger (144> 244 "344) associated with a vehicle traction chain and a pump (146, 246, 346), a third heat exchanger (162, 262, 362) common to the first sub-circuit (120, 220, 320) and to the second sub-circuit (140, 240, 340), the compressor (122, 222, 322) being configured to be started on startup for a period of less than 2 minutes. 8. Circuit according to the preceding claim, wherein the pump (146, 246, 346) is arranged upstream of the second heat exchanger (144> 244 "344) · 9- Circuit according to any one of claims 7 or 8, comprising a third sub-circuit (280, 380) independent of the first sub-circuit (120, 220, 320) and the second sub-circuit (140, 240, 340), the third sub-circuit (280, 380) comprising a fourth heat exchanger (282, 382). 10. Vehicle characterized in that it comprises a refrigerant circuit (100, 200, 300) according to any one of claims 7 to 9 ·