FR2780490A1 - SYSTEM FOR ADJUSTING THE TEMPERATURE IN THE INTERIOR OF AN ELECTRIC MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a system for adjusting the temperature in the passenger compartment of an electric motor vehicle, the energy of which is supplied by so-called high temperature batteries. The refrigerant circulation circuit comprises a main loop (2). having an interior heat exchanger (7) in the path of a first air flow sent into the passenger compartment and an exterior heat exchanger (9), a secondary loop (3) with a compressor (13) and a device switching (4) of the direction of circulation of the refrigerant in the main loop, so that the system can operate in heating mode or in cabin cooling mode (H). A water cooling circuit (5) allows to cool The batteries. This circuit comprises a bypass (50) which has a heat exchanger (54) of the liquid / air type in the path of the first air flow, and a heat exchanger (56) of the liquid / refrigerant type in the secondary loop (3). The cooling water goes through the bypass (50) in heating mode.

Description

The invention relates to a temperature control system in

  the passenger compartment of a motor vehicle with an electric motor or

  hybrid operating with so-called high temperature batteries.

  It relates more particularly to a system of the type comprising a circuit for circulating a refrigerant comprising a main loop containing an internal heat exchanger, suitable for exchanging heat with a first flow of air sent into the passenger compartment, an exchanger outside heat, suitable for exchanging heat with a second air flow and a pressure regulator interposed between the indoor heat exchanger and the outdoor heat exchanger, a secondary loop containing a compressor, and switching means between the main loop and the secondary loop for circulating the refrigerant in the main loop in a selected direction of circulation, so that the indoor heat exchanger and the outdoor heat exchanger function respectively as evaporator and as condenser in a mode cooling and respectively as a condenser and as an evaporator in a heating mode, the vehicle icule further comprising a liquid cooling circuit for cooling the batteries and the system

  vehicle electric drive.

  The refrigerant circulation circuit works on the principle of a reversible heat pump which allows, from the same basic components, to provide either heating or

  air conditioning of the passenger compartment of the motor vehicle.

  FR 2 740 397 has already proposed to include an evaporator connected to the cooling circuit of the power circuit associated with the electric motor of the vehicle in the secondary loop of the refrigerant circulation circuit, upstream of the compressor. In this system, the heat transferred by the power circuit, and in particular the batteries, is typically at a temperature level lower than that of the air sent into the passenger compartment in heating mode. The heat recovered by the refrigerant increases the temperature of the fluid upstream of the compressor. This heat is complementary to the heat

  taken from the outside air in heating mode.

  FR 2 721 863, on the other hand, provides in the main loop of the refrigerant circulation circuit, in parallel with the external heat exchanger, an exchanger of the liquid liquid type which allows the refrigerant to recover heat from the refrigeration circuit.

cooling in heating mode.

  In these two documents, in heating mode, the indoor heat exchanger must be of sufficient size to allow the

  heating of the passenger compartment, because it alone participates in this function.

  The object of the present invention is to at least partially discharge the interior heat exchanger in the vehicle heating mode, in order to reduce the electrical consumption necessary for the operation of the system, while taking advantage of the heat generated.

  by the vehicle’s batteries and drive system.

  The invention achieves its object by the fact that the cooling circuit comprises a bypass circuit comprising a liquid / air type heat exchanger disposed in the path of the first flow of air sent into the passenger compartment and a valve suitable for making circulate the coolant in the bypass circuit

heating mode.

  Advantageously, the valve is a three-way valve.

  According to a first alternative embodiment of the invention, the liquid / air type heat exchanger is arranged downstream of

  the indoor heat exchanger in the path of the first air flow.

  According to a second alternative embodiment, the heat exchanger of the liquid / air type is arranged upstream of the heat exchanger.

indoor heat.

  Advantageously, the bypass circuit further comprises a heat exchanger of the liquid / fluid type, capable of supplying energy to the refrigerant of the secondary loop upstream of the compressor. This heat exchanger is arranged downstream of

  the liquid / air type heat exchanger in the bypass circuit.

  There is also provided in the cooling circuit a

  radiator in the path of the second air flow.

  Thanks to the arrangements according to the invention, the battery coolant, in heating mode, directly participates in the partial heating of the air sent into the passenger compartment, the complement of

  heating required being provided by the reversible heat pump.

  Other advantages and characteristics of the invention will become apparent from

  reading the following description given by way of example and

  reference to the accompanying drawings in which: FIG. 1 is a schematic representation of a system for adjusting the temperature of a passenger compartment of an electric vehicle according to a first embodiment of the invention, used in heating mode; Figure 2 is a representation similar to that of Figure 1 in the cooling mode; Figure 3 is a diagram of a system according to a second embodiment of the invention, shown in heating mode; Figure 4 is a diagram of the system of Figure 3 in cooling mode; and FIG. 5 is a diagram of a system according to a third mode

  embodiment of the invention, shown in heating mode.

  In the drawings there is shown in broken lines a passenger compartment H of an electric or hybrid motor vehicle whose temperature is

  regulated by an adjustment system 1.

  This system includes a circuit for circulating a refrigerant having a main loop 2, a secondary loop 3 and a switching valve 4 of the four-way type, connecting the two loops 2 and 3 together, as well as a circuit for cooling of the power circuit of the electric motor fitted to the vehicle. This power circuit notably includes so-called high temperature batteries and the cooling circuit comprises a mixture of water.

and glycol, for example.

  The main loop 2 comprises a conduit 6 connecting the valve 4 to an interior heat exchanger 7 and a conduit 8 connecting the interior heat exchanger 7 to the valve 4 by passing through an exterior heat exchanger 9. On the conduit 8, between the indoor heat exchanger 7 and the outdoor heat exchanger 9 are placed,

  successively, a tank 10 and a regulator 11.

  The secondary loop 3 comprises a conduit 12 connecting the valve 4 to a compressor 13 and a conduit 14 which connects the compressor 13 to the

valve 4.

  The valve 4 can take two positions: a heating position, shown in FIGS. 1, 3 and 5 in which the refrigerant, compressed by the compressor 13, circulates through the conduit 6 from the valve 4 to the internal heat exchanger 7 , then returns to the valve 4 passing through the external heat exchanger 9; and a cooling position, shown in Figures 2 and 4, in which the refrigerant in the main loop 2 flows in the opposite direction. However, the refrigerant always flows in the same direction in the secondary loop 3, whatever the operating mode of the

system 1.

  The internal heat exchanger 7 is placed in an air duct 20 which has an air inlet 21 outside the passenger compartment 4 and an air outlet 22 inside the passenger compartment H, as well as a recirculation air inlet 23 opening directly into the passenger compartment H. A fan 24 also accommodates in the air duct 20 in order to send outside or recirculated air to the passenger compartment H through the heat exchanger

indoor heat 7.

  The external heat exchanger 9 is placed in an air duct 30 which has a first air inlet 31 coming from outside the passenger compartment H and an air outlet 32 opening to the outside, and a second air inlet 33 opening into the passenger compartment. The air inlet 31 is controlled by a flap 34. A fan 35, disposed near the air outlet 32 makes it possible to draw in a flow of air coming from inside the passenger compartment, as well as the if necessary, an air flow coming from outside the passenger compartment H, according to the position of the flap 34. This air flow

  passes through the outdoor heat exchanger 9.

  In the heating position of the valve 4, the indoor heat exchanger 7 acts as a condenser and heats the air flow passing through it, while the outdoor heat exchanger 9 plays the role of a

  evaporator and cools the air flow passing through it.

  In the valve cooling position 4, the indoor heat exchanger 7 plays the role of an evaporator and cools the air flow passing through it, while the outdoor heat exchanger 9 plays the role

  of a condenser and heats the air flow passing through it.

  The reference 40 represents the power circuit and the electric drive system of the vehicle, the elements of which are cooled by the liquid circulating in the cooling circuit 5 and driven by the pump 41. This liquid is typically a mixture of water and glycol. This circuit includes a hot water conduit 42 between the pump 41 and an external radiator 43 disposed in the air line 30 and a return conduit 44 connecting the radiator 43 and the pump 41. A bypass circuit 50 is provided between a three-way valve 51 mounted on the hot water pipe 42 and a point 52 of this pipe located downstream of the valve 51. This bypass circuit includes a pipe 53 connecting the valve 51 to a heat exchanger 54 of the type liquid / air placed in the air line 20 and a return line 55

  connecting the heat exchanger 54 to point 52.

  In the heating mode, as shown in Figure 1, the valve 51 directs the hot water from the cooling circuit to the heat exchanger 54. The indoor heat exchanger 7, playing the role of condenser, relieves the temperature of the air blown by the fan 24 at an intermediate temperature. Then, the air leaving the indoor heat exchanger 7 is heated from this intermediate temperature to the set temperature in the heat exchanger 54 which is traversed by the cooling water from the incoming batteries to a temperature of approximately 80 C. The three-way valve 51 makes it possible to regulate the water flow according to the heating requirement and according to

  the availability of cooling heat.

  The heat thus taken from the cooling circuit 5 performs the role of additional heating. It is activated when the heat pump cannot meet the heating requirement on its own, particularly during the initial heating phases or when the temperatures

exterior are very low.

  In the cooling mode, the three-way valve 51 does not

  does not supply liquid to the bypass circuit 50.

  The liquid / air heat exchanger 54 can be arranged in the path of the air flow delivered into the passenger compartment H downstream of the interior heat exchanger 7, as shown in FIGS. 1 to 4 , but it can also be placed upstream of the exchanger

  of internal heat 7, as shown in FIG. 5.

  Advantageously, the return duct 55 of the bypass circuit includes a second heat exchanger 56 interposed between the heat exchanger 54 of the liquid / air type and the point 52. This second exchanger 56 of the liquid / refrigerant type is connected

  to the conduit 12 of the secondary loop 3 upstream of the compressor 13.

  This embodiment is shown in Figures 3 to 5. According to a variant not shown in the drawings, the return duct 55 can be connected to the duct 42 upstream of the point 52, and this duct 42 is connected to the inlet of the second exchanger 56 by a second three-way valve. This embodiment makes it possible to take heat from the bypass circuit 50, in heating mode, at two temperature levels. A first sampling takes place in the heat exchanger 54 of the liquid / air type, located either downstream (FIG. 3) or upstream (FIG. 3) from the internal heat exchanger 7, in the same manner as in the embodiment of Figures 1 and 2. The coolant at a temperature of about 80 C cools in the exchanger 54 to an intermediate temperature and heats the air flow circulating in the air line 20. Then , the coolant passes through the exchanger 56 of the liquid / refrigerant type o it contributes to the evaporation of the refrigerant. The three-way valve 51 regulates the flow rate of liquid circulating in the heat exchanger 54 of the liquid / air type and the heat exchanger 56 of the liquid / refrigerant type. Heating resistors 60 of PTC type (positive temperature coefficient), playing the role of an additional additional heating, can be installed in the path of the air flow sent into the passenger compartment downstream of the interior heat exchanger 7 and

  of the liquid / air type heat exchanger 54.

Claims (8)

  1. System for adjusting the temperature in the passenger compartment (H) of a motor vehicle with an electric or hybrid motor, of the type comprising a circuit for circulating a refrigerant comprising a main loop (2) containing a heat exchanger interior (7) suitable for exchanging heat with a first air flow sent into the passenger compartment (H), an exterior heat exchanger (9) suitable for exchanging heat with a second air flow and a pressure reducer (11) interposed between the indoor heat exchanger (7) and the outdoor heat exchanger (9), a secondary loop (3) containing a compressor (13), and switching means (4) between the main loop (2) and the secondary loop (3) for circulating the refrigerant in the main loop (2) in a chosen direction of circulation, so that the internal heat exchanger (7) and the heat exchanger outside heat (9) function respectively as evaporator and as a condenser in a cooling mode and respectively as a condenser and as an evaporator in a heating mode, said vehicle operating with so-called high temperature batteries cooled by a liquid circulating in a cooling circuit (5), characterized in that the circuit cooling system (5) comprises a bypass circuit (50) comprising a heat exchanger (54) of the liquid / air type arranged in the path of the first air flow and a valve (51) suitable for circulating the cooling liquid in the circuit   bypass (50) in heating mode.   2. System according to claim 1, characterized in that the heat exchanger (54) of the liquid / air type is arranged downstream of   the indoor heat exchanger (7), in the path of the first air flow.   3. System according to claim 1, characterized in that the heat exchanger (54) of the liquid / air type is arranged upstream of   the indoor heat exchanger (7), in the path of the first air flow.   4. System according to any one of claims 1 to 3,   characterized by the fact that the branch circuit (50) further comprises a heat exchanger (56) of the liquid / fluid type, capable of supplying energy to the refrigerant of the secondary loop (3) in upstream of the compressor (13).   5. System according to any one of claims 1 to 4,   characterized in that the cooling circuit (5) includes a   radiator (43) in the path of the second air flow.   6. System according to any one of claims 1 to 5,   characterized by the fact that heating resistors (60) are installed   in the path of the first air flow.   7. System according to claim 6, characterized in that the   resistors (60) are of the positive temperature coefficient type.   8. System according to any one of claims 1 to 7,   characterized in that the valve (51) is a three-way valve.