FR3077376A1 - REFRIGERANT FLUID CIRCUIT FOR IMPROVED PERFORMANCE VEHICLE - Google Patents

Abstract

The invention relates to a refrigerant circuit (1) which comprises a main branch (2) with a main heat exchanger (3) and a compression device (9) and a first branch (4). and a second leg (5) which are both interposed between a first portion (20) and a second portion (22) of the main leg (2), the first leg (4) comprising a first heat exchanger (10) thermally coupled to an electrical storage device (11), the second branch (5) comprising a second heat exchanger (14) configured to heat-treat a passenger compartment, characterized in that the circuit (1) comprises a first internal heat exchanger (15) adapted to performing a heat exchange between the first portion (20) and the second portion (22) of the main branch (2), and a second internal heat exchanger (18) adapted to perform a heat exchange between the branch principal (2) and the second limb (5).

Description

The field of the present invention is that of refrigerant circuits for vehicles, in particular for motor vehicles.

Motor vehicles are commonly equipped with a refrigerant circuit used to cool different areas or different components of the vehicle. It is notably known to use this refrigerant circuit for thermally treating an air flow sent into the passenger compartment of the vehicle equipped with such a circuit.

In another application of this circuit, it is known to use it to cool an electrical storage device of the vehicle, the latter being used to supply energy to an electric motor capable of setting the vehicle in motion. The refrigerant circuit thus provides the energy capable of cooling the electrical storage device during its use in taxiing phases. The refrigerant circuit is thus dimensioned to cool this electrical storage device for heating temperatures of the electrical storage device which remain moderate.

When this refrigerant circuit simultaneously performs heat treatment of the passenger compartment and heat treatment of the electrical storage device, this circuit is subjected to very high stresses which bring the circuit to the limits of its capacities. This is particularly the case when the electrical storage device is used in a way which causes it to heat up considerably. An example of this situation is a rapid charge phase of the electrical storage device. It consists in charging the electrical storage device under a high voltage and amperage, so as to charge the electrical storage device in a maximum time of a few minutes. This rapid charge involves heating of the electrical storage device which must be treated. Furthermore, consideration must be given to the possibility of maintaining an acceptable level of thermal comfort inside the passenger compartment, either because the occupants of the vehicle remain inside the vehicle all or part of the charging time mentioned above, either to anticipate the return of these occupants and avoid any thermal discomfort. It is also necessary to thermally treat the passenger compartment during this rapid charge phase to maintain acceptable comfort conditions, in particular when the temperature outside the vehicle is above 30 ° C. These two requests for cooling imply a dimensioning of the system which makes it not very compatible with the constraints of current motor vehicles, in particular vehicles powered by an electric motor.

The technical problem therefore resides in the ability to increase the performance of a refrigerant circuit which is configured on the one hand to dissipate the calories generated by the electrical storage device when it is subjected to high stresses, for example during a rapid charge phase, and on the other hand to cool the passenger compartment, both by limiting the consumption and / or the bulk and / or the noise pollution of a system capable of simultaneously fulfilling these two functions.

The invention is part of this context and proposes a technical solution which solves this problem, by integrating two internal heat exchangers cleverly arranged one relative to the other in the circuit. Each of these internal heat exchangers implements a heat exchange between a high pressure portion of the circuit and respectively a first low pressure part and a second low pressure part of the circuit.

The invention therefore relates to a circuit for a motor vehicle configured to be traversed by a refrigerant, the circuit comprising at least one main branch comprising at least one main heat exchanger and a device for compressing the refrigerant, as well as a first branch and a second branch which extend between a point of divergence and a point of convergence and which are both interposed between a first portion of the main branch and a second portion of the main branch, the first branch comprising at least one first heat exchanger thermally coupled to an electrical storage device of the vehicle, the second branch comprising at least a second heat exchanger configured to heat treat a passenger compartment of the vehicle, characterized in that the circuit comprises a first internal heat exchanger capable of producing a heat exchange between the first p ortion of the main branch and the second portion of the main branch, as well as a second internal heat exchanger able to carry out a heat exchange between the main branch and the second branch.

The first internal heat exchanger thus implements a heat exchange between the refrigerant fluid subjected to high temperature and high pressure present in the main branch and the refrigerant fluid at low pressure and low temperature which circulates in the branch of the circuit which carries the first heat exchanger, that is to say that dedicated to the heat treatment of the electrical storage device. The second internal heat exchanger also implements a heat exchange between the refrigerant fluid subjected to high temperature and high pressure present in the main branch and the refrigerant fluid low pressure and low temperature which circulates in the branch of the circuit which carries the second heat exchanger, that is to say that dedicated to the heat treatment of the passenger compartment.

This organization avoids oversizing or overuse of circuit components, in particular the compression device. All other things being equal, the refrigerant circuit according to the invention is more efficient than a refrigerant circuit without the two internal heat exchangers. The cooling capacity developed by the circuit which is the subject of the invention is therefore greater than that which exists in the prior art.

This organization of the circuit also makes it possible to limit the acoustic nuisances, by operating the compression device at speeds lower than what would be the case in the absence of internal heat exchangers.

The refrigerant is for example a subcritical fluid, such as that known under the reference R134A or 1234YF. Alternatively, the fluid can be super-critical, such as carbon dioxide whose reference is R744. The refrigerant circuit according to the invention is a closed circuit which implements a thermodynamic cycle.

The compression device is for example a compressor, and the invention finds a very particular application when the compressor is an electric compressor with fixed displacement and variable speed. It is thus possible to control the thermal power of the circuit according to the invention. The compression device can include at least one compression mechanism driven by an electric motor, the rotation of which is controlled by a controller, possibly on board the compression device.

The first branch is in parallel with the second branch, seen from the refrigerant.

The point of divergence is the area of the circuit where the main branch, in particular its first portion, splits in two, forming the first branch and the second branch. The point of convergence is the area of the circuit where the first branch and the second branch join, to form the main branch, and more particularly the second portion.

The main heat exchanger can be installed on the front of the vehicle. This main heat exchanger can thus be used as a condenser, or gas cooler in the case of a super-critical fluid.

The first heat exchanger is configured to heat treat an electrical storage device of the vehicle. It is therefore specially dedicated to this electrical storage device and does not have the function of cooling another component. The first heat exchanger exchanges calories between the refrigerant and the electrical storage device of the vehicle, either directly, that is to say by convection between the first heat exchanger and the electrical storage device, or indirectly via a loop of heat transfer liquid, the latter being intended to transport the calories from the electrical storage device to the first heat exchanger. It is therefore understood that the cooling of the electrical storage device according to the invention can be indirect and in this case the first heat exchanger is a coolant / coolant heat exchanger. Alternatively and covered by the invention, the first heat exchanger can be in contact with the electrical storage device. In such a case, the cooling of the electrical storage device is direct.

Advantageously, the first internal heat exchanger comprises a first pass capable of being traversed by the refrigerant and disposed in the first portion of the main branch, as well as a second pass capable of being traversed by the refrigerant and disposed in the second portion of the main branch, the first pass and the second pass being configured to thermally exchange with each other. The first pass and the second pass therefore constitute the main branch, but in portions where the pressure and the temperature of the refrigerant are different.

Still advantageously, the second internal heat exchanger comprises a first ply capable of being traversed by the refrigerant and disposed on the main branch, as well as a second ply capable of being traversed by the refrigerant and disposed on the second branch , the first layer and the second layer being configured to thermally exchange with each other.

The first pass, the second pass, the first layer and the second layer form an internal volume, respectively of the first internal heat exchanger and the second internal heat exchanger, which is intended to be occupied by the refrigerant. These passes and layers can be parallel or can cross. The circulation of refrigerant fluid within them can be of the co-current or counter-current type.

Note that the first pass and the first layer are arranged in series in the main branch. On the high pressure side, the first pass and the first layer follow each other.

The second layer constitutes the second branch.

The first pass and the first layer are arranged so that the refrigerant circulates first in the first pass and then in the first layer. Seen from the refrigerant, the first pass is upstream of the first layer. Such an organization takes advantage of the fact that the evaporation temperature of the refrigerant in the first heat exchanger is higher than the evaporation temperature of the refrigerant in the second heat exchanger. There therefore remains a certain calorific capacity in the refrigerant after it has passed through the first pass, this capacity being able to be used in the heat exchange which takes place in the second internal heat exchanger.

According to one aspect of the invention, the first pass and the first ply are arranged on the main branch between an outlet of the main heat exchanger and the point of divergence.

The second pass is arranged on the first branch between an outlet of the first heat exchanger and an inlet of the compression device.

Advantageously, the second ply is disposed on the second branch between an outlet from the second heat exchanger and an inlet from the compression device.

The focal point can take many forms. It can first of all be a connection point where the first branch and the second branch join to reform the main branch, in particular the second portion of this main branch. In such a case, the second branch may comprise a compression means separate from the compression device arranged in the main branch, for example an electric compressor, responsible for circulating the coolant in the second branch, in particular in the second heat exchanger and in an expansion member associated therewith.

The point of convergence can also be formed by at least one ejector. This ejector performs a pressure reducer function with respect to the first heat exchanger and a function for circulating the coolant in the second branch. The ejector thus forms an expansion device for the refrigerant which participates in the thermodynamic cycle which takes place in the circuit according to the invention. The ejector also forms a means of circulating the coolant in the second branch. The Venturi effect generated by the ejector acts as a pump with regard to the refrigerant present in the second branch.

The circuit according to the invention may include at least one device for controlling the circulation of the coolant within the first branch. Advantageously, this control device takes the form of an all-or-nothing valve, or with a variable opening.

The circuit may also include a member for controlling the circulation of the coolant within the second branch. This control member can be arranged upstream and / or downstream of the second heat exchanger. It can for example be a stop valve or at least one expansion member of the refrigerant. In the latter case, the control member is arranged upstream of the second heat exchanger. The expansion member can be an electrically operated expansion member, controlled for example by electronic means. The expansion device is therefore controlled electrically or electronically.

This is how the control member can be placed on the second branch between the point of divergence and an inlet of the second heat exchanger. Alternatively, the control member is arranged on the second branch between an outlet of the second heat exchanger and the point of convergence. Advantageously, the control member is disposed between an outlet of the second ply and the point of convergence, the latter being for example formed by a secondary inlet of the ejector.

It will be noted that the control device is arranged on the first branch between the point of divergence and the point of convergence, and more particularly between the point of divergence and a primary input of the ejector.

According to a characteristic of the invention, at least one pipe connects the second branch to an inlet of the compression device. The pipeline can then comprise at least one valve for stopping the circulation of the refrigerant fluid within the pipeline.

According to another characteristic, the first heat exchanger is a coolant / heat transfer liquid heat exchanger.

The invention also covers a thermal treatment system of a motor vehicle, comprising an electric storage device for the motor vehicle and a circuit as described in this document, where the first heat exchanger cooperates with the electric storage device so to ensure at least its cooling. The heating of this electrical storage device can also be provided by this heat treatment system, in particular by operating the refrigerant circuit in heat pump mode.

The system mentioned above may include a ventilation, heating and / or air conditioning installation of the passenger compartment of the motor vehicle, in which the second heat exchanger is arranged in the ventilation, heating and / or air conditioning installation.

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:

- Figure 1 is a schematic view of the circuit according to the invention, in a first embodiment,

- Figure 2 is a schematic view of the circuit according to the invention, in a second embodiment,

- Figures 3 to 5 schematically illustrate the circuit shown in Figure 1, operated according to different modes of operation.

It should first of all be noted that the figures show the invention in detail in order to implement the invention, said figures can of course be used to better define the invention, if necessary. These figures are schematic representations which illustrate how the circuit is made, what composes it and how the refrigerant circulates within it. In particular, the circuit according to the invention mainly comprises at least one device for compressing the coolant, heat exchangers, organs and devices for controlling the circulation of the coolant, and pipes connecting each of these components. The circuit can also be placed under the control of a control unit which acts on some of these components.

The terms upstream and downstream used in the following description refer to the direction of circulation of the fluid considered, that is to say the refrigerant, an interior air flow sent to a passenger compartment of the vehicle or an air flow outside the passenger compartment of the vehicle. The fluid considered is symbolized by an arrow which illustrates the direction of circulation of the latter in the pipe considered. The solid lines illustrate a portion of the circuit where the refrigerant circulates, while the dotted lines show an absence of circulation of the refrigerant.

Figure 1 thus shows a circuit 1 inside which a refrigerant is able to circulate. This circuit 1 is a closed loop where the refrigerant is circulated by a compression device 9. It will be noted that this compression device 9 can take the form of an electric compressor, that is to say a compressor which includes a compression mechanism, an electric motor and possibly a controller. The compression mechanism is rotated by the electric motor, the speed of rotation of which is under the control of the controller, the latter being able to be external or internal to the compression device concerned, for example by being housed in a compressor housing.

According to the embodiments illustrated in the figures, the circuit 1 comprises a main branch 2, a first branch 4 and a second branch 5 which are in series with the main branch 2, so as to form a closed circuit where a thermodynamic cycle takes place .

The first branch 4 and the second branch 5 separate at a point of divergence 6 and meet at a point of convergence 7. Between these two points, first branch 4 and second branch 5 are in parallel, seen from the refrigerant.

The main branch 2 is divided into two portions separated from each other by the first branch 4 and by the second branch 5. The part of the main branch 2 which extends from an outlet 19 of the compression device 9 up to the point of divergence 6 is called the first portion 20 of the main branch 2. The part of the main branch 2 which extends from the point of convergence 7 to an inlet 21 of the compression device 9 is called the second portion 22 of the main branch 2.

The circuit 1 which is the subject of the invention also comprises at least a first heat exchanger 10 which is specifically dedicated to the heat treatment of an electrical storage device 11, the function of which is to supply electrical energy to one or more electric motors which put moving the vehicle. Such an electrical storage device 11 accumulates or restores this electrical energy in order to set the motor vehicle in motion, via the dedicated electric motor. For example, this is a battery pack grouping together plusieursο several electric cells that store electric current.

The first heat exchanger io can directly exchange calories with the electrical storage device il, by convection or by conduction. We are talking here about direct heat treatment of the electrical storage device il.

According to the examples illustrated in Figures 1 to 5, the first heat exchanger 10 is thermally coupled to the electrical storage device 11 via a loop of heat transfer liquid. This is then called indirect heat treatment of the electrical storage device 11. The heat transfer liquid thus captures the calories at the level of the electrical storage device 11, via a third heat exchanger 23, and transports them to the first heat exchanger 10. It will be noted that this third heat exchanger 23 takes the form of one or more mechanically carrying plates of the electrical storage device 11, which delimit between them a space traversed by the heat transfer liquid. The circulation of the heat transfer liquid in the loop 17 of heat transfer liquid is generated by at least one pump 24.

Innovatively, the refrigerant circuit 1 comprises a first internal heat exchanger 15 and a second internal heat exchanger 18 of similar constitution. The first internal heat exchanger 15 provides an exchange of calories between the refrigerant which circulates in the first portion 20 of the main branch 2 and the refrigerant which circulates in the second portion 22 of the main branch 2. The second heat exchanger internal ensures an exchange of calories between the refrigerant which circulates in the first portion 20 of the main branch 2 and the refrigerant which circulates in the second branch 5.

Seen from the refrigerant which circulates in the first portion 20 of the main branch 2, the first internal heat exchanger 15 is upstream from the second internal heat exchanger 18. Seen from the refrigerant which circulates in the second branch 5, the first exchanger internal heat 15 is parallel to the second internal exchanger 18.

The first internal heat exchanger 15 includes two passes which thermally exchange with each other. A first pass 25 of this first internal heat exchanger 15 forms part of the first portion 20 of the main branch 2, while a second pass 26 of this first internal heat exchanger 15 forms part of the second portion 22 of the branch main 2.

On the side of the second internal heat exchanger 18, this comprises a first ply 27 and a second ply 28 which exchanges heat with the first ply 27. The latter is part of the first portion 20 of the main branch 2, while the second ply 28 of this second internal heat exchanger 18 is part of the second branch 5, that is to say the branch which comprises the second heat exchanger 14.

The first pass 25 of the first internal heat exchanger 15 and the first ply 27 of the second internal heat exchanger 18 are arranged in series one behind the other between an outlet 29 of a main heat exchanger 3 and the point of divergence 6 where the first branch 4 and the second branch 5 separate.

The main branch 2 extends from the point of convergence 7 to the point of divergence 6 and comprises at least the main heat exchanger 3 and the compression device 9. This main heat exchanger 3 is intended to be crossed by the refrigerant and by an external air flow. This main heat exchanger 3 is the seat of a heat exchange between the refrigerant and this external air flow and it can be used as a condenser, as will be seen in the description of Figures 3 to 5. This heat exchanger main heat 3 can be installed on the front of the vehicle equipped with the circuit 1 according to the invention and in this situation it is crossed by the air flow outside the passenger compartment of the vehicle (this heat exchanger can also be a refrigerant exchanger / coolant).

The first branch 4 begins at the point of divergence 6, ends at the point of convergence 7 and comprises a device 16 for controlling the circulation of the coolant in the first branch 4. According to an exemplary embodiment, the control device 16 takes the form of a stop valve 8 configured to totally allow or totally prohibit the passage of the coolant through it.

The second branch 5 begins at the point of divergence 6, ends at the point of convergence 7 and successively and according to the direction of circulation of the coolant in the second branch 5 at least one control member 13, a second heat exchanger 14 and the second internal heat exchanger 18. It will be noted that, alternatively or cumulatively, the control member 13 can be arranged downstream of the second internal heat exchanger 18, in particular between an outlet of the latter and the point of convergence 7 In such a case, the control member 13 may have a stop function similar to that of the stop valve 8 placed in the first branch 4.

The control member 13 can also be arranged upstream of the second heat exchanger 14, and it can then be a pressure relief member 12 whose function is to ensure a pressure drop of the refrigerant fluid. The expansion member 12 can act on a thermal power implemented by the second heat exchanger 14, by being able to vary this thermal power from the maximum power of the second heat exchanger 14 to all thermal powers lower than this maximum power. . The expansion member 12 can be either a thermostatic expansion valve, an electronic expansion valve, a tube orifice or the like.

According to a variant of the invention, the point of convergence 7 is an area where the first branch 4 and the second branch 5 join. In this situation, the coolant circuit 1 may include a means for compressing the coolant installed in the second branch, the function of which is to circulate the coolant FR in the second branch 5, so as to cool the flow of water. air passing through the second heat exchanger 14.

According to an exemplary embodiment illustrated in the figures, the point of convergence 7 takes the form of an ejector 30. The latter is a component which performs a first function of the coolant expansion valve, as well as a second function of circulating of the coolant in the second branch 5. This ejector 30 therefore forms a device for expanding the coolant and a means of circulating the coolant in the second branch, thanks to the Venturi effect which it generates.

The ejector 30 thus comprises a main inlet 31 of coolant connected to the first branch 4, a secondary inlet 32 of coolant connected to the second branch 5, and an outlet 33 connected to the second portion 22 of the main branch 2.

The ejector 30 can act on a thermal power implemented by the first heat exchanger 10, by being able to vary this thermal power from the maximum power of the first heat exchanger 10 to all thermal powers lower than this maximum power.

The ejector 30 also makes it possible to have two separate evaporation pressures in the exchangers 10 and 14, for example the evaporation pressure in the heat exchanger 10 is higher than that of the heat exchanger 14.

The second heat exchanger 14 is intended to heat treat an interior air flow which is sent inside the passenger compartment of the vehicle. The second heat exchanger 14 can be installed inside a ventilation, heating and / or air conditioning installation which cooperates with the circuit 1, to form a heat treatment system for the motor vehicle. This second heat exchanger 14 can then be used as an evaporator to cool the interior air flow which is sent into the passenger compartment of the vehicle.

The circuit 1 according to the invention may also include a pipe 34 arranged in parallel with the second portion 22 of the main branch 2. This pipe 34 thus extends from the second branch 5 to the main branch 2. The pipe 34 s' extends between a first point 35, located between an outlet of the second heat exchanger 14 and an inlet of the stop valve 8, and a second point 36 disposed between an outlet of the first internal heat exchanger 15 and the inlet 21 of the device compression 9.

Line 34 may include a stop valve 37 which authorizes or prohibits the circulation of the refrigerant fluid in line 34, from the first point 35 and towards the second point 36.

Figure 2 shows a second embodiment of the refrigerant fluid circuit 1. The components and their relative arrangements are identical to what has been described in relation to FIG. I except for the following. For these identical elements, reference will be made to the description of FIG. I in order to understand the technical characteristics thereof.

In this embodiment, the control member 13 takes the form of a thermostatic expansion valve 38 including the stop valve function. The expansion of the cooling fluid operated by this thermostatic expansion valve 38 is placed under the dependence of the temperature of the cooling fluid leaving the second heat exchanger 14. This thermostatic expansion valve 38 can also completely close the circuit, and thus prevent any circulation of cooling fluid in the second branch 5. It will be noted that in such a situation, the second branch 5 may be devoid of the stop valve 8 which is disposed between the outlet of the second heat exchanger 14 and the secondary inlet 32 of the ejector 30 in the first embodiment illustrated in FIG. 1.

In Figures 3 to 5, the strong lines illustrate the FR refrigerant when it is subjected to high pressure and high temperature, while the thin lines show the FR refrigerant when it is at low pressure and low temperature.

Figure 3 shows the circuit 1 illustrated in Figure 1 and used in the simultaneous cooling mode of the electrical storage device 11 and the passenger compartment. This is particularly the case of a rapid charge imposed on the electrical storage device 11, while the occupants remain in the vehicle during the time of this rapid charge.

In such a mode, the compression device 9 is in operation and compresses the refrigerating fluid FR. The main heat exchanger 3 discharges the calories from the refrigerating fluid FR into the external air flow F1. The refrigerating fluid FR thus subjected to high pressure passes through the first layer 25 of the first internal heat exchanger 15, and it exchanges calories with the refrigerant FR which circulates in the second portion 22 of the main branch 2. At the outlet of the first sheet 25, the refrigerant FR continues its course and crosses the first pass 27 of the second internal heat exchanger 18, and it exchanges calories with the FR refrigerant which circulates in the second branch 5.

Arriving at the point of divergence 6, the refrigerant FR separates in two to supply each of the branches 4, 5. The refrigerant FR thus circulates both in the first branch 4 and in the second branch 5. The control device 16 is in the open position and authorizes the circulation of the coolant fluid up to the primary inlet 31 of the ejector 30. The shape of the latter causes a Venturi effect which sucks in the coolant FR present in the second branch 5 ·

The expansion member 12 generates a pressure drop which allows the second heat exchanger 14 to act as an evaporator. It is then possible to cool an internal air flow F2 which passes through the second heat exchanger 14 before it is sent into the passenger compartment of the vehicle.

The control member 13 is placed in an open position, thus authorizing the refrigerant fluid FR present in the second branch 5 to join the secondary inlet 32 of the ejector 30. The refrigerant fluid FR which enters the ejector 30 by the secondary inlet 32 is sucked in by the refrigerant FR which enters via the main inlet 31, and these two parts of refrigerant combine at the outlet of the ejector 3 to supply the second portion 22 of the main branch

2.

The circulation of refrigerant FR is prohibited in the pipe 34, thanks to the fact that the stop valve 37 is placed in a closed position.

The refrigerant FR then passes into the first heat exchanger 10 where it cools the heat transfer liquid LC which circulates in the heat transfer liquid loop 17. In doing so, the electrical storage device 11 is cooled by means of the third heat exchanger 23.

The invention makes it possible to carry out two internal heat exchanges which ultimately improve the overall performance of the refrigerant circuit 1 FR, this improvement being achieved by the first internal heat exchanger 15 and by the second internal heat exchanger 18 as described above.

Figure 4 shows the circuit 1 illustrated in Figures 1 and 3 and used in priority cooling mode of the electrical storage device 11, that is to say a mode where the thermal energy is concentrated to cool the thermal storage device he. This is particularly the case of a rapid charge imposed on the electrical storage device il, while the occupants do not occupy the vehicle during the time of this rapid charge. The interior is therefore not cooled.

In such a mode, the compression device 9 is in operation and compresses the refrigerating fluid FR. The main heat exchanger 3 discharges the calories of the refrigerant FR into the outside air flow F1. The refrigerant FR circulates in the main branch 2 and then exclusively in the first branch 4.

The ejector 30 expands the FR refrigerant and the first heat exchanger 10 cools the electrical storage device 11. The FR refrigerant is then sucked by the compression device 9 to implement a new thermodynamic cycle.

On the side of the second branch 5, the stop valve 37 and the control member 13, whether it is placed upstream or downstream of the second heat exchanger 14, are closed, preventing any circulation of coolant in the second heat exchanger 14. The latter is thus inoperative.

In this operating mode, the first internal heat exchanger 15 is active and transfers heat between the high pressure and high temperature FR refrigerant which circulates in the first portion 20 of the main branch 2 and the circulating FR refrigerant. at low pressure and low temperature in the second portion 22 of the main branch 2. The first pass 25 thus exchanges calories with the second pass 26. In this situation, the second internal heat exchanger 18 is inoperative.

Figure 5 shows the circuit 1 illustrated in Figures 1, 3 and 4 used in priority cooling mode of the passenger compartment of the vehicle, that is to say a mode where the thermal energy is concentrated to quickly cool the flow d interior air F2 sent into the passenger compartment. This mode can be activated when the temperature outside the passenger compartment is high, for example above 30 ° C, and the vehicle users wish to cool the passenger compartment very quickly. The cooling of the electrical storage device is not ensured in this mode.

In such a mode, the compression device 9 is in operation and compresses the refrigerating fluid FR. The main heat exchanger 3 discharges the calories of the refrigerating fluid FR into the external air flow F1. The refrigerating fluid FR circulates in the main branch 2 and then exclusively in the second branch 5, thanks to the fact that the first control 16 is closed. Any circulation of refrigerant in the first heat exchanger 10 is thus prevented.

The expansion member 12 achieves expansion of the refrigerant fluid FR and the second heat exchanger 14 cools the interior air flow F2 sent to the passenger compartment. The variable opening of the second expansion member 12 manages the cooling power which should be applied to the interior air flow F2 to reach the temperature required in the passenger compartment. The refrigerant FR is sucked by the compression device 9, thanks to the fact that part of the refrigerant which has passed through the second heat exchanger 14 passes through the pipe 34. To do this, the stop valve 37 is placed in an open position where it allows circulation of the coolant from the second branch 5 to the compression device 9.

In this operating mode, the second internal heat exchanger 18 implements a heat exchange between the high pressure and high temperature refrigerant FR which passes through the first sheet 27 and the low pressure and low temperature refrigerant which passes through the second layer 28.

The operating modes described in connection with FIGS. 3 to 5 apply in the same way to the second embodiment as illustrated in FIG. 2.

The circuit 1 of refrigerant fluid FR according to the first embodiment or according to the second embodiment may comprise means for acquiring information relating to circuit 1, to the electrical storage device 11 or to the passenger compartment, and means for acting on the components of this circuit 1 so as to reach fixed setpoints, in particular coolant temperatures or rotational speeds of the compression device 9. This management of circuit 1 can be carried out by a control device which can take the form an enclosure or an electronic unit. This control device acts on the speed of rotation of the compression device 9, in particular when it is a compressor with an integrated electric motor and with fixed displacement.

The above description is given by way of example, and it is understood that the invention more broadly covers the use of two internal heat exchangers 10, one of which constitutes a branch of the circuit dedicated to cooling the electrical storage device, while the other internal heat exchanger constitutes a branch of the circuit dedicated to cooling the passenger compartment of the vehicle.

The invention cannot however be limited to the means and configurations described and illustrated here, and it also extends to all equivalent means or configurations and to any technically operating combination of such means. In particular, the architecture of the refrigerant circuit can be modified without harming the invention insofar as it fulfills the functionalities described in this document.

Claims (10)

1. Circuit (1) for a motor vehicle configured to be traversed by a coolant (FR), the circuit (1) comprising at least one main branch (2) comprising at least one main heat exchanger (3) and a device for compression (9) of the refrigerant (FR), as well as a first branch (4) and a second branch (5) which extend between a point of divergence (6) and a point of convergence (7) and which are both interposed between a first portion (20) of the main branch (2) and a second portion (22) of the main branch (2), the first branch (4) comprising at least a first heat exchanger (10) thermally coupled to an electrical storage device (11) of the vehicle, the second branch (5) comprising at least a second heat exchanger (14) configured to heat treat a passenger compartment of the vehicle, characterized in that the circuit (1) comprises a first exchanger internal heat (15) able to carry out a heat exchange between the first portion (20) of the main branch (2) and the second portion (22) of the main branch (2), as well as a second internal heat exchanger (18 ) suitable for carrying out a heat exchange between the main branch (2) and the second branch (5). 2. Circuit (1) according to claim 1, wherein the first internal heat exchanger (15) comprises a first pass (25) adapted to be traversed by the refrigerant fluid (FR) and disposed in the first portion (20) of the main branch (2), as well as a second pass (26) capable of being traversed by the refrigerant fluid (FR) and disposed in the second portion (22) of the main branch (2), the first pass (25) and the second pass (26) being configured to thermally exchange with each other. 3. Circuit (1) according to claim 1 or 2, wherein the second internal heat exchanger (18) comprises a first ply (27) capable of being traversed by the coolant (FR) and disposed on the main branch (2 ), as well as a second ply (28) capable of being traversed by the refrigerant (FR) and disposed on the second branch (5), the first ply (27) and the second ply (28) being configured to heat exchange with each other. 4 · Circuit (ι) according to claim 3, wherein the first pass (25) and the first ply (27) are arranged in series in the main branch (2). 5. Circuit (1) according to the preceding claim, wherein the first pass (25) and the first ply (27) are arranged so that the coolant (FR) flows first in the first pass (25) then in the first layer (27). 6. Circuit (1) according to any one of the preceding claims, wherein the point of convergence (7) is formed at least by an ejector (30). 7. Circuit (1) according to any one of the preceding claims, comprising a control device (16) of the circulation of the refrigerant fluid (FR) within the first branch (4). 8. Circuit (1) according to any one of the preceding claims, comprising a control member (13) of the circulation of the coolant (FR) within the second branch (5). 9. Circuit (1) according to any one of the preceding claims, in which at least one pipe (34) connects the second branch (5) to an inlet (21) of the compression device (9). 10. A heat treatment system for a motor vehicle, comprising an electric storage device (11) of the motor vehicle and a circuit (1) according to any one of the preceding claims, in which the first heat exchanger (10) cooperates with the electrical storage device (11) so as to ensure at least its cooling.