FR3067796A1 - HEAT PUMP HEATING CIRCUIT FOR A MOTOR VEHICLE AND METHOD FOR MANAGING THE SAME - Google Patents

Abstract

The present invention relates to a heat pump heating circuit (1) for an electric or hybrid vehicle comprising a refrigerant circulation loop (A) in which a refrigerant fluid is able to circulate and which comprises, in the direction of circulation of the refrigerant: ° a compressor (3), ° a first heat exchanger (5), ° a first expansion device (7), ° a second heat exchanger (9) to be crossed by an outside air flow (100), a second expansion device (11), and a third heat exchanger (13) disposed within a heating, ventilation and / or air conditioning device (40), said third heat exchanger (13) ) being intended to be traversed by an interior air flow (200) to the passenger compartment.

Description

The invention relates to the field of electric and hybrid motor vehicles and more particularly to a heat pump heating circuit for such a motor vehicle and its management method.

In the field of electric and hybrid vehicles, it is difficult to reconcile good autonomy of the batteries and efficient heating of the passenger compartment, it is known to use a heat pump heating circuit, in particular at start-up, when the engine of hybrid vehicles is cold. These circuits generally comprise successively a compressor, a condenser intended to heat an air flow going towards the passenger compartment, an expansion device and an evaporator intended to take heat from the outside air.

However, these heat pump heating circuits may not be efficient enough to reach the set heating temperature requested by the user, especially when the outside temperature is low, for example between 3 and 10 ° C, see even below 0 ° C.

One of the aims of the present invention is therefore to at least partially remedy the drawbacks of the prior art and to propose a method of heating a heat pump of the passenger compartment of an improved electric or hybrid vehicle as well as its method of management. .

The present invention therefore relates to a heat pump heating circuit for an electric or hybrid vehicle comprising a coolant circulation loop in which a coolant is able to circulate and which comprises, in the direction of coolant circulation:

° a compressor, ° a first heat exchanger, ° a first expansion device, ° a second heat exchanger intended to be traversed by an external air flow, ° a second expansion device, and ° a third heat exchanger disposed within a heating, ventilation and / or air conditioning device, said third heat exchanger being intended to be traversed by an interior air flow intended for the passenger compartment.

According to one aspect of the invention, the first heat exchanger is disposed within the heating, ventilation and / or air conditioning device, said first heat exchanger being intended to be traversed by an internal air flow intended for the cockpit and being placed downstream of the third heat exchanger in the direction of circulation of the interior air flow.

According to another aspect of the invention, the first heat exchanger is a two-fluid heat exchanger disposed jointly on the coolant loop and on a coolant loop in which circulates a coolant, said coolant loop comprising a pump as well as a fourth heat exchanger, said fourth heat exchanger being disposed within the heating, ventilation and / or air conditioning device, said fourth heat exchanger being intended to be traversed by an internal air flow intended for the cabin and being placed downstream of the third heat exchanger in the direction of circulation of the interior air flow.

According to another aspect of the invention, the heat pump heating circuit comprises a bypass loop comprising at least a fifth heat exchanger intended to exchange heat energy with electrical elements.

According to another aspect of the invention, the heat pump heating circuit includes a device for redirecting the refrigerant or the heat transfer fluid to the bypass loop.

According to another aspect of the invention, the heating, ventilation and / or air conditioning device comprises a bypass pipe of the first heat exchanger or the fourth heat exchanger.

The present invention also relates to a method of managing a heat pump heating circuit as described above in which, for an outside temperature between 3 and 15 ° C, the first expansion device undergoes a pressure loss at the coolant so that the temperature of the coolant leaving said second expansion device is lower than the temperature of the external air flow before it passes through the second heat exchanger.

According to one aspect of the process of the invention, the pressure loss of the refrigerant fluid at the level of the first expansion device is greater for an outside temperature between 3 and 10 ° C than for an outside temperature between 10 and 15 ° C .

According to another aspect of the process of the invention, for an outside temperature above 15 ° C, the first expansion device causes the refrigerant to lose pressure so that the temperature of the refrigerant leaving the second expansion device is higher than the temperature of the external air flow before it passes through the second heat exchanger.

According to another aspect of the process of the invention, for an outside temperature below 3 ° C, the outside air flow passes through a bypass pipe of the third heat exchanger within a heating, ventilation and / or air conditioning so as to bypass said third heat exchanger.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and of the appended drawings among which:

FIG. 1 shows a schematic representation of a heat pump heating circuit according to a first embodiment, FIG. 2 shows a schematic representation of a heat pump heating circuit according to a second embodiment, • Figures 3a to 3c show a schematic representation of variants of the heat pump heating circuit of Figures 1 and 2, • Figure 4 shows a schematic sectional view of a heating, ventilation and / or air conditioning device, • Figures 5 to 7 show schematic pressure / enthalpy diagrams according to different modes of operation of the heat pump heating circuit.

In the various figures, identical elements have the same reference numbers.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to a single embodiment. Simple features of different embodiments can also be combined and / or interchanged to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, for example first element or second element as well as first parameter and second parameter or again first criterion and second criterion, etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria close, 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.

In the present description, the term "placed upstream" means that one element is placed before another with respect to the direction of circulation of a fluid. Conversely, by "placed downstream" is meant that one element is placed after another with respect to the direction of circulation of the fluid.

Figure 1 shows a representation of a heat pump heating circuit 1, in particular for an electric or hybrid vehicle, comprising a coolant circulation loop A in which a coolant is able to circulate. This refrigerant circulation loop A comprises, in the direction of circulation of the refrigerant:

° a compressor 3, ° a first heat exchanger 5, ° a first expansion device 7, ° a second heat exchanger 9 intended to be traversed by an external air flow 100, ° a second expansion device 11, and ° a third heat exchanger 13 disposed within a heating, ventilation and / or air conditioning device 40, said third heat exchanger 13 being intended to be traversed by an internal air flow 200 intended for the passenger compartment.

The first expansion device 7 can more particularly be an expansion device, the opening of which can be controlled in order to control the pressure of the refrigerant fluid at its outlet. The first expansion device 7 may also be able to be traversed by the flow of refrigerant without loss of pressure when it is open to its maximum. The first expansion device 7 may also include a stop function, that is to say that it is capable of blocking the flow of refrigerant fluid.

The second expansion device 11 may in turn be a tube orifice calibrated to obtain a defined pressure at its outlet.

The refrigerant circulation loop A can also include a phase separation device 15, for example a desiccant bottle, disposed upstream of the compressor 3, between the third heat exchanger 13 and said compressor 3.

In order to create the interior air flow 200, the heating, ventilation and / or air conditioning device 40 may in particular comprise a first fan 17. Likewise, in order to create the exterior air flow 100, the motor vehicle may include a second fan 19 placed near the second heat exchanger 9. Generally, the second fan 19 and the second heat exchanger 9 are arranged on the front face of the motor vehicle.

Figure 1 shows a heat pump heating circuit 1 according to a first embodiment. In this first embodiment, the heat pump heating circuit 1 is direct, that is to say that the first heat exchanger 5 is disposed within the heating, ventilation and / or air conditioning device 40. This first heat exchanger 5 is then intended to be traversed by an interior air flow 200 intended for the passenger compartment and is placed downstream of the third heat exchanger 13 in the direction of circulation of the interior air flow 200.

According to a second embodiment illustrated in FIG. 2, the heat pump heating circuit 1 is indirect, that is to say that the first heat exchanger 5 is a two-fluid heat exchanger disposed jointly on the loop. refrigerant A and on a coolant loop B in which a coolant circulates. This heat transfer fluid loop B comprises in particular a pump 23 as well as a fourth heat exchanger 21.

This fourth heat exchanger 21 is more particularly arranged within the heating, ventilation and / or air conditioning device 40. The fourth heat exchanger 21 is intended to be traversed by the internal air flow 200 intended for the passenger compartment and is placed downstream of the third heat exchanger 13 in the direction of circulation of the interior air flow 200.

As shown in Figures 3a, 3b and 3c, the heat pump heating circuit 1 can also include a bypass loop C, C ', C ”comprising at least a fifth heat exchanger 27 for exchanging energy heat with electrical elements. These electrical elements can more particularly be the batteries of an electric or hybrid motor vehicle. However, it is quite possible to imagine other electrical elements such as power electronics and / or the electric motor. Depending on how the fifth heat exchanger 27 is connected to the heat pump heating circuit 1, the latter can allow the heating or cooling of the electrical elements.

In the examples illustrated in Figures 3a to 3cb, the bypass loop C, C ', C ”has only one heat exchanger called here fifth heat exchanger 27. However it is quite possible to imagine that the bypass loop C, C ', C ”includes several heat exchangers arranged in series or in parallel with each other in order to be connected to different elements to be heated or even to another thermal management circuit such as the cooling circuit of the thermal engine of a hybrid vehicle.

According to a first variant illustrated in Figures 3a and 3b, the fourth heat exchanger 27 is connected so as to heat the electrical elements.

When the heat pump heating circuit is according to the first embodiment as illustrated in FIG. 3a, the bypass loop C is notably arranged between;

• a first junction point C1 placed on the coolant circulation loop A downstream of the compressor 3, between said compressor 3 and the first heat exchanger 5, and • a second junction point C2 placed on the coolant circulation loop A downstream of the first connection point C1, between said first connection point C1 and the first heat exchanger 5.

When the heat pump heating circuit is according to the second embodiment as illustrated in FIG. 3b, the bypass loop C ’is notably arranged between;

• a first junction point C'I placed on a heat transfer fluid loop B downstream of the first heat exchanger 5, between said first heat exchanger 5 and the fourth heat exchanger 21, and • a second junction point C ' 2 placed on a heat transfer fluid loop B downstream of the first junction point C'I, between said first junction point C '1 and the fourth heat exchanger 21.

According to a second variant illustrated in FIG. 3c, the fourth heat exchanger 27 is connected so as to cool the electrical elements. The bypass loop C ”is then placed between;

• a first junction point C ”1 placed on a coolant circulation loop A upstream of the third heat exchanger 13, between the second expansion device 11 and said third heat exchanger 13, and • a second junction point C ”2 placed on a refrigerant circulation loop A downstream of the third heat exchanger 13, between said p of the third heat exchanger 13 and the compressor 3, more precisely upstream of the phase separation device 15.

In order to control the path taken by the coolant, the heat pump heating circuit 1 can also include a device for redirecting the coolant to the bypass loop C, C ’, C”. This coolant redirection device may in particular include:

• a first stop valve 29 placed between the first C1, C'I, C ”1 and the second C2, C'2, C” 2 connection point, and • a second stop valve 29 'placed on the branch loop C, C ', C44, for example downstream of the first connection point C'I, between said first connection point Cl, C'l, C ”1 and the fifth heat exchanger 27.

According to another variant, not shown, of the first or of the second embodiment, it is possible to integrate an electric heater, for example a resistance with a positive temperature coefficient. In the context of the first embodiment, this electric heater can be arranged upstream of the first heat exchanger 5 in order to heat the refrigerant. In the context of the second embodiment, this electric heater can be arranged upstream of the fourth heat exchanger 21 in order to heat the heat transfer fluid. Another possibility is also to place the electric heater in the interior air flow 200 downstream of the first heat exchanger 5 or the fourth heat exchanger 21.

As shown in FIG. 4, the heating, ventilation and / or air conditioning device 40 more particularly comprises a supply pipe 41a for outside air and a supply pipe 41b for recirculated air (that is to say that comes from of the passenger compartment). These two supply lines 41a and 41b both supply air to the third heat exchanger 13 so that it passes through it. In order to choose where the air passing through the third heat exchanger 13 comes from, the heating, ventilation and / or air conditioning device 40 comprises a shutter 410a, for example a drum type shutter, capable of completely closing or partially the supply line 41a for outside air or the supply line 41b for recirculated air. The recirculated air supply line 41b may also include a shutter 410b so as to be obstructed.

The heating, ventilation and / or air conditioning device 40 further comprises a bypass pipe 41c of the third heat exchanger 13. Said bypass pipe 41c of the third heat exchanger 13 is thus able to bring outside air directly into the of the heating, ventilation and / or air conditioning device 40 without passing through the third heat exchanger 13. The bypass pipe 41c of the third heat exchanger 13 also includes a shutter 410c capable of closing it completely or partially . This bypass pipe 41c allows the heat pump heating circuit 1 to operate with outside air temperatures below 3 ° C and more particularly negative temperatures. Indeed, the outside air flow 100 can thus not pass through the third heat exchanger 13 and thus the risks of frost formation on the latter are reduced.

Within it, the heating, ventilation and / or air conditioning device 40 comprises a heating pipe 42a which makes it possible to bring air having passed through the third heat exchanger 13 or through its bypass pipe 41c at the first heat exchanger 5 or the fourth heat exchanger 21 (according to the embodiment of the heat pump heating circuit 1) so that it passes through it and is reheated before arriving in a distribution chamber 43. heating 42a also includes a shutter 420a capable of closing it totally or partially.

The heating, ventilation and / or air conditioning device 40 may also include a bypass line 42b of the first heat exchanger 5 or the fourth heat exchanger 21. This bypass line 42b allows the air being passed through the third heat exchanger to heat 13, or via its bypass line 41c, to go directly into the distribution chamber 43, without passing through the first heat exchanger 5 or the fourth heat exchanger 21. This bypass line 42b also includes a shutter shutter 420b able to close it totally or partially.

At the distribution chamber 43, the air can be sent to the windshield by an upper pipe 44a, the dashboard of the passenger compartment by a middle pipe 44b and / or to the bottom of the dashboard of the passenger compartment by a lower pipe 44c. Each of these pipes 44a, 44b, 44c comprising a shutter 440 capable of closing them completely or partially.

As illustrated in FIG. 4, the first fan 17 can be disposed between the third heat exchanger 13 and the first heat exchanger 5. However, it is quite possible to imagine another location for said first fan 17 without going outside the frame of the invention, for example upstream of the third heat exchanger 13 and its bypass pipe 41c, according to the direction of circulation of the interior air flow.

The present invention also relates to a method for managing a heat pump heating circuit 1 as described above.

Figures 5 to 7 show diagrams pressure P (bar), enthalpy H (J / kg) of the refrigerant within the heat pump heating circuit 1 and more precisely of the refrigerant loop A, according to different values of outside temperature. Curve X corresponds to the saturation curve of the refrigerant.

1) First management mode for an outside temperature between 3 and 10 ° C:

FIG. 5 shows a first mode of management of the heat pump heating circuit for an outside temperature between 3 and 10 ° C.

Initially, the refrigerant is at low pressure and in the gaseous state and passes into the compressor 3 where it undergoes a pressure increase as shown in arrow 300. The refrigerant is then at high pressure.

The refrigerant then passes into the first heat exchanger 5 where it loses enthalpy as shown in arrow 500. The amount of enthalpy lost at the first heat exchanger 5 is variable as a function of the outside temperature. The lower the outside temperature, the greater the amount of enthalpy lost.

Then the refrigerant passes through the first expansion device 7 where it undergoes a first loss of pressure illustrated by the arrow 700. The magnitude of this pressure loss at the level of the first expansion device 7 makes it possible to define the temperature of the refrigerant at the second heat exchanger 9 in order to obtain a temperature difference between the temperature of the outside air flow 100 before it passes through the second heat exchanger 9 and the temperature of the refrigerant leaving the first expansion device 7.

As shown in FIG. 5, for an outside temperature between 3 and 10 ° C., the first expansion device 7 causes a significant loss of pressure in the refrigerant fluid so that the temperature of the refrigerant fluid leaving the first expansion device 7 is lower than the temperature of the outside air flow 100 before it passes through the second heat exchanger 9. For example, the pressure loss can be greater than 80% of the difference between the high pressure of the refrigerant leaving the compressor 3 and the low pressure of the refrigerant at the inlet of said compressor 3.

The refrigerant then passes through the second heat exchanger 9. Because the refrigerant is in the liquid phase and at a pressure close to its low pressure at the outlet of the first expansion device 7, it can more easily recover heat on contact outside air at the second heat exchanger 9 in order to restore it at the first heat exchanger 5, even if the temperature of this outside air is between 3 and 10 ° C. Indeed, as the outside temperature is said to be low (for example between 3 and 10 ° C), it is necessary to provide enough heat to heat it to a set temperature, the heat recovery needs are therefore significant.

The second heat exchanger 9 then acts as an evaporator and the refrigerant in the liquid state gains enthalpy and changes to the biphasic state as shown in arrow 900.

After passing through the second heat exchanger 9, the refrigerant in the biphasic state passes into the second expansion device 11 where it undergoes a second pressure loss, illustrated by arrow 110, to arrive at low pressure.

The refrigerant then passes through the third heat exchanger 13 where it continues to gain enthalpy in contact with the air passing through the heating, ventilation and / or air conditioning device 40, as shown in arrow 130

The refrigerant then joins the compressor 3.

The pressure drop of the coolant at the first expansion device 7 allows said coolant to reach a temperature such that at the second heat exchanger 9, the temperature difference with the temperature of the outside air flow 100 before passing through said second heat exchanger 9, regulates the heating power of the heat pump heating circuit 1 as a function of the desired temperature of the interior air flow 200 at the outlet of the heat pump heating circuit 1 .

2) Second management mode for an outside temperature between 10 and

15 ° C:

Figure 6 shows a second mode of management of the heat pump heating circuit for an outside temperature between 10 and 15 ° C.

Initially, the refrigerant is at low pressure and in the gaseous state passes into the compressor 3 where it undergoes a pressure increase as shown in arrow 300. The refrigerant is then at high pressure.

The refrigerant then passes into the first heat exchanger 5 where it loses enthalpy as shown in arrow 500. The amount of enthalpy lost at the first heat exchanger 5 is variable as a function of the outside temperature. The lower the outside temperature, the greater the amount of enthalpy lost.

Then the refrigerant passes through the first expansion device 7 where it undergoes a first loss of pressure illustrated by the arrow 700. The magnitude of this pressure loss at the level of the first expansion device 7 makes it possible to define the temperature of the refrigerant at the second heat exchanger 9 in order to obtain a temperature difference between the temperature of the outside air flow 100 before it passes through the second heat exchanger 9 and the temperature of the refrigerant leaving the first expansion device 7.

As shown in Figure 6, for an outside temperature between 10 and 15 ° C, the first expansion device 7 undergoes a moderate loss of pressure in the refrigerant so that the temperature of the refrigerant leaving the first expansion device 7 is lower than the temperature of the outside air flow 100 before it passes through the second heat exchanger 9. Because the outside temperature is higher than the first management mode, the pressure loss can then be less. For example, the pressure loss can be between 60 and 40% of the difference between the high pressure of the refrigerant at the outlet of the compressor 3 and the low pressure of the refrigerant at the inlet of said compressor 3.

The refrigerant then passes through the second heat exchanger 9. Because the refrigerant is in the liquid phase and at a median pressure relative to its low pressure at the outlet of the first expansion device 7, it can recover sufficient heat on contact outside air at the second heat exchanger 9 in order to restore it at the first heat exchanger 5 and this because the temperature of the outside air is between 10 and 15 ° C. Indeed, as the outside temperature is said to be median, it is less necessary to provide heat to heat it to a set temperature.

The second heat exchanger 9 then acts as an evaporator and the refrigerant in the liquid state gains enthalpy as shown in arrow 900.

After passing through the second heat exchanger 9, the refrigerant in the biphasic state passes into the second expansion device 11 where it undergoes a second pressure loss, illustrated by arrow 110, to arrive at low pressure.

The refrigerant then passes through the third heat exchanger 13 where it continues to gain enthalpy in contact with the air passing through the heating, ventilation and / or air conditioning device 40, as shown in arrow 130

The refrigerant then joins the compressor 3.

As previously, the loss of pressure of the refrigerant at the first expansion device 7 allows said refrigerant to reach a temperature such that at the second heat exchanger 9, the temperature difference with the flow temperature outside air 100 before it passes through said second heat exchanger 9, regulates the heating power of the heat pump heating circuit 1 as a function of the desired temperature of the interior air flow 200 at the outlet of the heating circuit with heat pump 1.

3) Third management mode for an outside temperature above 15 ° C:

Figure 7 shows a first mode of management of the heat pump heating circuit for an outside temperature above 15 ° C.

Initially, the refrigerant is at low pressure and in the gaseous state passes into the compressor 3 where it undergoes a pressure increase as shown in arrow 300. The refrigerant is then at high pressure.

The refrigerant then passes into the first heat exchanger 5 where it loses enthalpy as shown in arrow 500. The amount of enthalpy lost at the first heat exchanger 5 is variable as a function of the outside temperature. The lower the outside temperature, the greater the amount of enthalpy lost.

Then the refrigerant passes through the first expansion device 7 where it undergoes a first loss of pressure illustrated by the arrow 700. The magnitude of this pressure loss at the level of the first expansion device 7 makes it possible to define the temperature of the refrigerant at the second heat exchanger 9 in order to obtain a temperature difference between the temperature of the outside air flow 100 before it passes through the second heat exchanger 9 and the temperature of the refrigerant leaving the first expansion device 7.

As shown in FIG. 7, for an outside temperature higher than 15 ° C., the first expansion device 7 makes the low refrigerant pressure drop so that the temperature of the cooling fluid leaving the first expansion device 7 is higher than the temperature of the outside air flow 100 before it passes through the second heat exchanger 9. For example, the pressure loss can be less than 30% of the difference between the high pressure of the refrigerant leaving the compressor 3 and the low pressure of the refrigerant at the inlet of said compressor 3.

The refrigerant then passes through the second heat exchanger 9. Because the refrigerant is at a relatively high pressure at the outlet of the first expansion device 7 and therefore at a temperature higher than the outside temperature, it will not recover from the heat in contact with the outside air at the second heat exchanger 9 but will yield.

The second heat exchanger 9 then acts as a condenser and the refrigerant in the liquid state loses enthalpy, as shown in arrow 900.

After passing through the second heat exchanger 9, the refrigerant in the liquid state passes into the second expansion device 11 where it undergoes a second pressure loss, illustrated by arrow 110, to arrive at low pressure.

The refrigerant then passes through the third heat exchanger 13 where it continues to gain enthalpy in contact with the air passing through the heating, ventilation and / or air conditioning device 40, as shown in arrow 130

The refrigerant then joins the compressor 3.

Due to the outside temperature above 15 ° C, the amount of heat energy recovered from the third heat exchanger 13 is very large and it is necessary to evacuate part of it in the outside air flow 100 at the level of the second heat exchanger 9.

In the context of this third management mode, if the heating, ventilation and / or air conditioning device 40 redirects the internal air flow 200 in the bypass pipe 42b of the first heat exchanger 5 or of the fourth heat exchanger 21, the interior air flow 200 is no longer heated and can be used for strict cooling of the passenger compartment of the motor vehicle.

These three modes of management of the heat pump heating circuit 1 also allow, for example, cooling of the interior air flow 200 at the third heat exchanger 13 and then heating of said interior air flow 200 at the level of the first heat exchanger 5 or the fourth heat exchanger 21 in particular in order to carry out dehumidification.

Thus, it can be seen that the heat pump heating circuit 1 allows, by its architecture and its management modes, sufficient heating power when the outside temperature is low, that is to say at least understood between 3 and 10 ° C. In addition, for temperatures above 15 ° C, the heat pump heating circuit 1 also allows dehumidification or cooling of the interior air flow 200 intended for the passenger compartment.

Claims (12)

1. Heat pump heating circuit (1) for an electric or hybrid vehicle comprising a coolant circulation loop (A) in which a coolant is able to circulate and which comprises, in the direction of coolant circulation: ° a compressor (3), ° a first heat exchanger (5), ° a first expansion device (7), ° a second heat exchanger (9) intended to be traversed by an external air flow (100) , ° a second expansion device (11), and ° a third heat exchanger (13) disposed within a heating, ventilation and / or air conditioning device (40), said third heat exchanger (13) being intended to be traversed by an interior air flow (200) intended for the passenger compartment. 2. Heat pump heating circuit (1) according to claim 1, characterized in that the first heat exchanger (5) is disposed within the heating, ventilation and / or air conditioning device (40), said first exchanger heat (5) being intended to be traversed by an interior air flow (200) intended for the passenger compartment and being placed downstream of the third heat exchanger (13) in the direction of circulation of the interior air flow (200). 3. A heat pump heating circuit (1) according to claim 1, characterized in that the first heat exchanger (5) is a two-fluid heat exchanger disposed jointly on the coolant loop (A) and on a loop of heat transfer fluid (B) in which a heat transfer fluid circulates, said heat transfer fluid loop (B) comprising a pump (23) and a fourth heat exchanger (21), said fourth heat exchanger (21) being arranged at the within the heating, ventilation and / or air conditioning device (40), said fourth heat exchanger (21) being intended to be traversed by an interior air flow (200) intended for the passenger compartment and being placed downstream of the third heat exchanger (13) in the direction of circulation of the interior air flow (200). 4. Heat pump heating circuit (1) according to one of the preceding claims, characterized in that it comprises a bypass loop (C, C ', C ”) comprising at least a fifth heat exchanger (27 ) intended to exchange heat energy with electrical elements. 5. A heat pump heating circuit (1) according to the preceding claim, characterized in that it includes a device for redirecting the refrigerant or heat transfer fluid to the bypass loop (C, C ’, C”). 6. Heat pump heating circuit (1) according to one of claims 2 to 5, characterized in that the heating, ventilation and / or air conditioning device (40) comprises a bypass pipe (42b) of the first exchanger heat (5) or the fourth heat exchanger (21). 7. A method of managing a heat pump heating circuit according to one of claims 1 to 6, characterized in that for an outside temperature between 3 and 15 ° C, the first expansion device (7) makes undergo a loss of pressure in the coolant so that the temperature of the coolant leaving said second expansion device (7) is lower than the temperature of the external air flow (100) before it passes through the second heat exchanger (9 ). 8. A method of managing a heat pump heating circuit according to the preceding claim, characterized in that the pressure loss of the coolant at the first expansion device (7) is greater for an outside temperature between 3 and 10 ° C only for a 5 outside temperature between 10 and 15 ° C. 9. A method of managing a heat pump heating circuit according to one of claims 1 to 6, characterized in that for an outside temperature above 15 ° C, the first expansion device (7) undergoes a loss of 10 coolant pressure so that the temperature of the coolant leaving said second expansion device (7) is higher than the temperature of the external air flow (100) before it passes through the second heat exchanger (9). 15 10. Method for managing a heat pump heating circuit according to one of claims 1 to 6, characterized in that for an outside temperature below 3 ° C, the outside air flow (100) passes by a bypass pipe (41c) of the third heat exchanger (13) within a heating, ventilation and / or air conditioning device (40) so as to bypass Said third heat exchanger (13).