FR2905309A1 - AIR CONDITIONING SYSTEM FOR A MOTOR VEHICLE WITH SECONDARY CIRCUIT FOR FEEDING THE BATTERY - Google Patents

Abstract

The invention relates to an air conditioning system for a vehicle, in particular a hybrid motor vehicle, equipped with a heat engine (2), a direct or indirect thermal exchange means with a battery (5) and a hydraulic circuit. , said system comprising an evaporator (41), a heater (3) and means for supplying air to the heater at the outlet of the evaporator, characterized in that it comprises: a hydraulic circuit for supplying the heat engine (21) - a hydraulic circuit for supplying the heater (31) and- a secondary hydraulic circuit (51) for supplying the battery, connected to the hydraulic supply circuit of the heater.

Description

I AIR CONDITIONING SYSTEM FOR MOTOR VEHICLE WITH CIRCUIT

  The present invention relates to an air conditioning system for a motor vehicle having life conditions in which the heat engine is stopped during the driving phase. In general, an air conditioning system for cooling the passenger compartment of a motor vehicle comprises a heat exchanger system comprising an evaporator, a compressor, a condenser, an expander and a fluid that can change states: liquid / gas, as shown in the diagram in figure 1. The compressor: Directly driven by the vehicle's engine using a belt and a pulley, it compresses refrigerant, pushing it back under high pressure and at high pressure. temperature to the condenser. The condenser: Thanks to a forced ventilation, this heat exchanger causes the condensation of the gas which reaches the gaseous state at high pressure and high temperature. It liquefies it by lowering the temperature of the air passing through it. Evaporator: This is the last component of the air conditioning system. It is a heat exchanger, like the condenser that takes calories from the air that will be blown into the cabin (it cools the air and dries it). Moisture taken from the air flows on the fins of the evaporator and is gradually evacuated under the vehicle. The regulator: The regulator is a component that regulates the flow rate of gas entering the loop via a change of passage section depending on the temperature and the pressure at the evaporator.

  Thus, the warm air coming from outside cools by passing through the evaporator while also drying out because the moisture present in the outside air sticks on the cold surface of the evaporator. When the engine is stopped, the traditional air conditioning system is no longer operational. This is notably the case for hybrid motor vehicles, which are designed to operate in alternating mode on a thermal engine and an electric motor. In the case of so-called Full Hybrid operation, the electric motor can substitute for the engine for traction of the vehicle and this, during relatively long time intervals. The air-conditioning problem not supplied by the present and active means coupled to the heat engine are even more acute than those which can be encountered in SU-type hybrid engine applications in which the engine is only stopped for short periods of time. . In order to solve the problem of supplying cold to the passenger compartment on hybrid applications, various solutions are currently envisaged: maintaining the refrigerant circuit during operation during the stopping phase of the engine (by using an electric compressor and no longer to a compressor powered by the engine as explained in the introduction of the present application) - cold storage system accumulating frigories in the operating phase of the engine and releasing them in the stopping phase of the engine.

In parallel, another problem related to the thermal management of the traction battery (supply of calories and frigories) can appear: - if the battery is too cold (eg: cold start in winter): the performance of the battery is severely limited if the battery is too hot (ex .: rolling in summer): the battery life is greatly reduced. In this context of hybrid application and management optimized in terms of consumption, the present invention relates to a system, 3o to better manage the intake of frigories or calories according to the hot or cold climatic conditions for both the passenger compartment for the battery and in particular to bring hot and cold to the battery via the engine water circuit in cold and hot climatic conditions.

More specifically, the subject of the invention is an air-conditioning system for a vehicle, in particular a hybrid motor vehicle, equipped with a heat engine, with a means of direct or indirect thermal exchange with a battery, and with a hydraulic circuit, said system comprising an evaporator, a heater and means for supplying air to the heater at the outlet of the evaporator, characterized in that it comprises: a hydraulic circuit for supplying the heat engine; hydraulic power supply of the heater and a secondary hydraulic supply circuit of the exchanger 10 comprising the battery, connected to the hydraulic supply circuit of the heater. According to a variant of the invention, the hydraulic supply circuit of the heater and the secondary hydraulic circuit are connected via a three-way valve. According to a variant of the invention, the air-conditioning system furthermore comprises means for dissociating the hydraulic power supply circuit of the heat engine from the hydraulic power supply circuit of the heater, these means can typically comprise two hydraulic ducts mounted in accordance with the invention. parallel. According to a variant of the invention, the means for dissociating the hydraulic power supply circuit of the heat engine from the hydraulic circuit for supplying the heater comprises a three-way valve, making it possible to feed the hydraulic power supply circuit of the heater. unit heater 25 in closed circuit. According to a variant of the invention, the part of the hydraulic supply circuit of the heater comprises an electric pump. According to a variant of the invention, the system comprises means making it possible to vary the supply air flow rate of the heater. According to a variant of the invention, the part of the hydraulic power supply circuit of the engine comprises diverting means 2905309 4 The invention will be better understood and other advantages will appear on reading the following description given as a non-limiting and thanks to the appended figures among which: - Figure 1, already described, illustrates an air conditioning device according to the prior art; - Figure 2, already described, illustrates an air conditioning system according to the prior art; FIGS. 3a and 3b schematize the temperature changes ~ o of air in the air-conditioning unit in the cold mode possible engine stopped. These temperatures are given in the summer phase, respectively when the heat engine is running (air heater storing cold and thus heating the air) and when it is at a standstill (air heater restoring cold to air and therefore drying it out). and cooling it); FIGS. 4a, 4b, 4c, 4d and 4e illustrate a first variant of the invention concerning a system equipped with an engine bypass and are respectively relative to the architecture and the operations of this architecture according to different living conditions: Figure 4b relating to a heating of the passenger compartment and the battery (common need in winter); Figure 4c relating to a cooling of the passenger compartment and the battery (eg: common need in summer); Figure 4d relating to a heating of the passenger compartment but not the battery 25 (ex .: battery already hot in winter); FIG. 4d relates to a cooling of the passenger compartment and not of the battery (eg priority for cooling the passenger compartment relative to the battery) and - FIG. 5 illustrates a second variant of the invention for a application not equipped with an engine bypass. In known manner, there are air conditioning systems using the heater in the heat engine to generate hot air in the passenger compartment; the heater is a 2905309 heat exchanger 5 whose function is to heat the pulsed air in the passenger compartment. This heating is obtained by a heat exchange between the liquid of the hot loop from the cooling circuit of the engine and the air pulsed into the passenger compartment. Above a certain outside temperature, the heater is no longer supposed to bring calories to the passenger compartment. FIG. 2 illustrates this configuration: firstly, the hydraulic cooling circuit of the thermal engine comprises, in a conventional manner, a radiator 1 associated with the heat engine 2 coupled to a hydraulic cooling circuit comprising a first part 21 comprising a water pump 22, a water box 23 and a thermostat 24 for controlling and controlling the flow of coolant output of the engine. The hydraulic circuit also comprises a second part 31 comprising an electric pump 32 for supplying a heater 3.

On the other hand, the air conditioning unit 4 including an evaporator 41, sends cooled air into the heater that heats it. Typically air at 5 ° C. at the outlet of the evaporator can emerge from the heater at a temperature of 7 ° C. and thus provide fresh air into the passenger compartment by conventional means of distribution of the air means. treated including ducts, shutters and ventilation nozzles. The heater then stores cold when the engine is running in summer. Engine stopped, the air heats up and evaporates at the evaporator, but will be condensed at the heater. The operation of this type of system is hereinafter described in more detail and in FIGS. 3a and 3b. As illustrated in FIG. 3a, under the action of the heat engine, the evaporator can typically cool a hot air at approximately 30 ° C., taken from the outside at a temperature of approximately 5 ° C. This cooled air is then sent into the atmosphere. heater that by heat exchange with a water flow from the hydraulic circuit independent of the cooling circuit of the engine generates a cooling water (the air is then a little warmer at the output of the heater compared to its entry (7 C compared to 5 C).

When the engine is shut down, as shown in FIG. 3b, the evaporator is no longer operational, the air entering at 30 ° C., comes out at 30 ° C., to enter the heater and benefit from the inertia of this heater. last to be a little cooled, passing in the example shown at a temperature of 5 12 C. According to the invention, and advantageously, the air conditioning system of the known art can be adapted, optimized and coupled to a hydraulic circuit supplying the battery or an exchanger comprising the battery which the vehicle is equipped with in order to take advantage of the storage of calories or frigories present in said system when the engine is running or stopped and the battery has also need to be heated or cooled. In the following description, the exchanger comprising the battery 15 will be called battery but it could very well also be an exchanger located upstream of a battery and which cools the fluid flow through the latter. For this purpose a first variant of the invention and illustrated in FIG. 4a, proposes an air conditioning system comprising a bypass pipe connected with the hydraulic supply circuit 31 of the heater 3 and a hydraulic circuit 51 for feeding the battery. 5. It should be noted that the latter, shown downstream of the supply circuit of the heater, could just as well be upstream in another variant of the invention. The air conditioning system of the invention is illustrated schematically in FIG. 4a in the context of a motor bypass application. More precisely in this configuration, the engine equipped with a bypass on the engine water circuit has the following specificity: when the engine thermostat is closed (that is to say when there is no flow in the radiator on the front of the vehicle), a large flow of water is maintained in the engine because of the passage of water both in the air heater branch but also by a low pressure drop tube. The two hydraulic circuits 31 and 51 can advantageously be connected via a three-way valve 61. The hydraulic circuit 21 for supplying the heat engine and the hydraulic circuit 31 for supply can, moreover, be separated by the presence of the two conduits 33. and 34 and a three-way valve 60; the duct 33 being the duct forming part of the heat engine. Figure 4b schematizes the operation of this variant during a request for heating of the passenger compartment and the battery (common need 5 in winter). The duct 34 is represented in this case by a dashed line because it is not operational, the hydraulic supply circuit of the engine is not dissociated from the hydraulic supply circuit of the heater. Figure 4c schematizes the operation of this variant during a request for cooling of the passenger compartment and the battery (eg common need in summer). In this case, the hydraulic supply circuits of the heat engine and of the heater unit are dissociated. Figure 4d shows the operation of this variant during a request for heating the passenger compartment but not the battery (eg battery already hot in winter). The hydraulic power supply circuits of the motor and the power supply of the heater are not dissociated, while the power supply of the battery and the power supply of the heater are. Figure 4e schematizes the operation of this variant during a request for cooling of the passenger compartment and not the battery (eg priority to cooling the passenger compartment relative to the battery). The supply circuits of the motor and the heater are dissociated, the battery supply circuit being also dissociated from that of the heater.

Generally speaking, during a request for cooling the cabin combined with a request for cooling the battery, the operation of the air conditioning system according to the invention can typically be as follows: In summer, when the heat engine is running it is possible to produce cold water via the heater (provided that the air leaving the evaporator is directed into the heater). In parallel, the cold water can be redirected to the battery to cool it. When the engine is stopped, the cold power stored can bring cold to the passenger compartment, or even to the battery (according to priority management).

Such a configuration is also particularly well suited to respond to a defogging demand (requiring a supply of hot and cold at the air conditioning unit). Indeed, in this condition of life, it is necessary that the heater brings warm 5 and that the evaporator brings cold. The air conditioning system according to the invention is also well suited to a configuration in which the engine is equipped with an engine bypass, for which a thermostat in the closed position (that is to say when there is no flow in the radiator in the front of the vehicle) ensures a large flow of water in the engine due to the passage of water on the heater branch and because of the use of a low-pressure tube pressure drop, that for configurations in which the hydraulic circuit comprises for example an additional water circuit to overcome the motor bypass. FIG. 5 illustrates a second variant of the invention in the context of a motor not equipped with an engine bypass. More specifically in this configuration, the engine without a bypass on the engine water circuit has the following specificity: when the engine thermostat is closed (that is to say when there is no flow in the radiator on the front of the vehicle), the entire flow of water passing through the motor flows in the air heater branch. The presence of a minimum water flow in the engine is necessary to ensure its proper operation.

Means such as a second water circulation pipe 34 in parallel with a pipe 35 and water flow control means 62 in the hydraulic circuit of the heater, allow the water to be recycled into the water. hydraulic circuit of the heater at a temperature different from that flowing in the engine.

The heat exchange can take place during the entire shutdown of the engine. A flow of air at a given temperature passes through the heater to come out in the form of air flow at a temperature corresponding gradually to a stabilized temperature, defined to be the chosen air temperature to be diffused in the passenger compartment.

Typically, at each passage of the water at a given temperature upstream of the heater, the heater will emerge at a lower temperature until it converges to a predetermined temperature, making it possible to regulate the temperature of the air flow. To converge towards this air flow at the desired temperature, it is possible to control the percentage of flow rate of water passing through the heater according to the mode coupled or not to the hydraulic circuit of the engine, by regulating the flow of water by via the electric pump and the three-way valve plus a non-return valve, 61.

Claims (10)

  1. A vehicle air conditioning system, in particular a hybrid motor vehicle, equipped with a heat engine, a means of direct or indirect heat exchange with a battery (5) and a hydraulic circuit, said system comprising an evaporator (41), a heater (3) and means for supplying air to the heater at the outlet of the evaporator, characterized in that it comprises: a hydraulic circuit for supplying the heat engine (21) - a hydraulic circuit the heater (31) and - a secondary hydraulic circuit (51) for supplying the exchanger ~ o comprising the battery, connected to the hydraulic supply circuit of the heater.   2. An air conditioning system according to claim 1, characterized in that the hydraulic supply circuit of the heater and the secondary hydraulic circuit are connected via a three-way valve (61).   3. Air conditioning system according to claim 2, characterized in that the hydraulic supply circuit of the heater and the hydraulic supply circuit of the engine are separated by a three-way valve (60).   4. The air conditioning system according to one of claims 1 to 3, characterized in that it further comprises means for dissociating the hydraulic supply circuit of the engine of the hydraulic supply circuit 25 of the heater.   5. Air conditioning system according to claim 4, characterized in that the means for dissociating the hydraulic supply circuit of the engine of the hydraulic supply circuit of the heater 30 comprises two hydraulic ducts connected in parallel (33,34, 35) 2905309 11   6. Air conditioning system according to claim 5, characterized in that the means for disassociating the hydraulic supply circuit of the engine of the hydraulic supply circuit of the heater comprises a three-way valve for feeding the circuit 5 hydraulic supply of the heater in closed circuit.   7. Air conditioning system according to one of claims 4 to 6, characterized in that the means for dissociating the hydraulic supply circuit of the engine of the hydraulic supply circuit of the heater comprises at least one check valve .   8. Air conditioning system according to one of claims 1 to 7, characterized in that the hydraulic supply circuit of the heater comprises an electric pump.   9. The air conditioning system according to one of claims 1 to 8, characterized in that it comprises means for varying the supply air flow rate of the heater. 20   10. Air conditioning system according to one of claims 1 to 9, characterized in that the portion of the hydraulic supply circuit of the engine comprises bypass means.