EP2057026A1

EP2057026A1 - Air-conditioning system for a car

Info

Publication number: EP2057026A1
Application number: EP07823701A
Authority: EP
Inventors: Pierre Dumoulin
Original assignee: Peugeot Citroen Automobiles SA
Current assignee: PSA Automobiles SA
Priority date: 2006-08-30
Filing date: 2007-08-07
Publication date: 2009-05-13
Also published as: WO2008025916A1; FR2905310B1; FR2905310A1

Abstract

The invention relates to an air-conditioning system for a car, particularly for a hybrid electric car, equipped with a heat engine (2) and a hydraulic circuit, the said system comprising an evaporator (41), a unit heater (3), means to provide air to the unit heater at the evaporator exit, characterized in that: - the system comprises means (33, 34,35) for separating the part of the hydraulic circuit (21) powering the heat engine from the part of the hydraulic circuit (31) powering the unit heater in that: - the part of the hydraulic circuit powering the unit heater comprises a hydraulic tank (5).

Description

AIR CONDITIONING SYSTEM FOR A MOTOR VEHICLE

The present invention relates to an air conditioning system for a vehicle, in particular a hybrid 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 of Figure 1.

The compressor: Directly driven by the vehicle's engine using a belt and a pulley, it compresses refrigerant, delivering it under high pressure and at high 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 particularly the case for hybrid motor vehicles, which are designed to operate alternately on the engine and the electric motor. In the case of a so-called "FuII hybrid" operation, the electric motor can replace the thermal engine for traction of the vehicle during relatively long time intervals. The problem of air conditioning not powered by the present and active means, coupled to the heat engine are even more acute than those which can be encountered in hybrid engine applications of the type "STT" in which the engine is stopped only during short moments.

To overcome the problem of non-operating cooling of the engine, it has been proposed to use the heater, as a substitute for the cooling circuit, by passing the air leaving the evaporator in the heater, when the engine thermal is cut.

The heater is a heat exchanger whose function is to heat the air drawn into 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 drawn into the passenger compartment. Above a certain outside temperature, the unit heater is no longer supposed to bring calories to the cabin. Figure 2 illustrates this configuration:

On the one hand, the hydraulic cooling circuit of the heat engine conventionally comprises a radiator 1, associated with the heat engine 2 coupled to a hydraulic cooling circuit comprising a first portion 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 comprising in particular an evaporator 41 sends cooled air into the heater which 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 for distributing the means of the heater. treated air comprising ducts of the distribution flaps and ventilation nozzles.

The heater then stores cold when the engine is running. Engine stopped, the air heats up and evaporates at the evaporator, but will be condensed and cooled at the heater. In this context, the present invention proposes to combine the use of the hydraulic circuit feeding the heater to the use of a hydraulic tank. In this way, the hydraulic circuit is a source of cold when the engine is stopped and the reservoir is an additional source of cold to provide sufficient cooling during the extended shutdown of the engine. The combination of these cold sources is particularly suitable for applications for which the motor can be stopped for long periods. Such a configuration is also interesting for storing calories to continue to warm the cabin of the vehicle in winter, when the engine is stopped.

More specifically, the subject of the invention is an air conditioning system, for a motor vehicle equipped with a heat engine, an electric motor, for example of the alternator-starter type, and a hydraulic circuit, said system comprising an evaporator , a heater, means for supplying air to the heater at the outlet of the evaporator, characterized in that:

the system comprises means for dissociating the part of the hydraulic supply circuit of the heat engine from the part of the hydraulic supply circuit of the heater and that:

- the part of the hydraulic supply circuit of the air heater includes a hydraulic tank

According to a variant of the invention, the hydraulic reservoir contains brine.

According to a variant of the invention, the part of the hydraulic supply circuit of the heater comprises a parallel circuit in which is incorporated the hydraulic tank.

According to a variant of the invention, the means for dissociating the part of the hydraulic supply circuit of the heat engine from the portion of the hydraulic supply circuit of the heater comprises two hydraulic ducts connected in parallel.

According to a variant of the invention, the means for dissociating the part of the hydraulic supply circuit of the heat engine and the part of the hydraulic supply circuit of the heater include a valve three-way, to supply the portion of the hydraulic circuit supplying the heater in a closed circuit.

According to a variant of the invention, the means for dissociating the hydraulic supply circuit portion of the heat engine and the portion of the hydraulic supply circuit of the heater comprise at least one non-return valve.

According to a variant of the invention, the portion of the hydraulic supply circuit of the heater comprises an electric pump.

According to a variant of the invention the air conditioning system comprises means of derivations.

According to a variant of the invention, the air conditioning system comprises means for controlling the hydraulic circuits, the electric pump and means for varying the supply air flow rate of the heater. According to a variant of the invetion the air conditioning system is characterized in that the management of the three-way valve, the pump and the air conditioning unit is carried out according to the ambient conditions, the customer requests, or even the driving conditions of the vehicle.

The invention will be better understood and other advantages will become apparent on reading the description which follows given by way of non-limiting example and by virtue of 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 operation of an air conditioning system using the heater to cool the passenger compartment when, respectively, when the engine is running and when it is stationary;

FIGS. 4a and 4b illustrate a first variant of the system of the invention structurally and in summer operating mode;

FIG. 5 illustrates a second variant of the system of the invention; - Figure 6 illustrates a variant of the invention in the context of an application not equipped with a "bypass" engine.

As part of the management of cold to bring to the cabin, especially in summer, the system of the invention uses the cold management device present in a motor vehicle and more specifically the evaporator for generating air cooled towards the heater. Indeed, 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 heater that by heat exchange with a flow of water from the hydraulic circuit independent of the cooling circuit of the engine generates a cooling water (the air is then a little hotter out of the unit heater compared to its entry (7 ⁰ C compared to 5 ⁰ C).

When the engine is stopped, as shown in Figure 3b, the evaporator is no longer operational, the air returning to 30 ⁰ C, is 30 ⁰ C, to enter the heater and benefit from the inertia of this last to be a little cooled, passing in the example shown at a temperature of 12 ⁰ C. According to the device of the invention, the cold air leaving the evaporator in winter, passes through the heater supplied with water hot from the cooling circuit of the engine. Heat exchanges that take place on the air flow injected into the heater increase the temperature of said air flow as shown in Figure 3a.

To amplify the cold storage beyond the capacity of the heater and to ensure a cooling of the passenger compartment when the engine is shut off, the present invention proposes adding a hydraulic reservoir to the hydraulic circuit part that feeds the engine. 'heater. The air conditioning system of the invention is illustrated schematically in FIG. 4a according to a first variant of the invention:

The hydraulic circuit comprises means such as a second water circulation pipe 34 and means for adjusting the water flow rate 60 in the hydraulic circuit of the heater, making it possible to recycle the water at a variable temperature in said hydraulic circuit of the heater. The system further comprises a reservoir 5 placed on the hydraulic circuit portion 34. This additional reserve cooling water is used when the engine is stopped.

In summer mode, as shown in Figure 4b, the hydraulic circuits are dissociated. The supply portions of the heater and the motor are separated by the three-way valve 60. When the heater is supplied in a closed circuit, the energy stored in the associated hydraulic circuit is increased by the presence of the hydraulic reservoir. 5. The power exchanged between this part of the hydraulic circuit and the heater, allows to cool a flow of air at room temperature through the heater better than in the absence of storage volume.

FIG. 5 illustrates a second variant of the invention, in which the hydraulic storage tank 5 is integrated in a circuit connected in parallel with the part of the hydraulic supply circuit of the heater. This parallel circuit is connected and controlled via a second three-way valve 61. The three-way valve can be advantageously replaced by a thermostat.

The air conditioning system according to the invention is also well suited to a configuration in which the engine is equipped with a "motor bypass", for which a thermostat in the closed position (that is to say when it does not). there is no flow in the radiator on the front of the vehicle) ensures a large flow of water in the engine due to the passage of water on both the air heater branch, but also by a low loss tube load, only for configurations in which the hydraulic circuit comprises for example an additional water circuit to overcome the "engine bypass". Thus, Figure 6 illustrates a variant of the invention in the context of a motor not equipped with a "bypass" engine.

Means such as a second water circulation pipe 34 in parallel with a pipe 35 and means for adjusting the water flow rate 62 in the hydraulic circuit of the heater, make it possible to recycle the water into the water. hydraulic circuit of the heater at a temperature different from that flowing in the engine.

The above variants have been described in the context of a need for cooling the cabin. Thus, if the storage tank contains chilled water before stopping the vehicle, its frigories will be stored via this tank when the vehicle stops. This cooled water can be used again during the next start.

The system of the invention may also be of interest outside the summer period:

In fact, it is possible to store calories at the end of the use of the vehicle so that they can be re-injected at the next start. The procedure is as follows when the end of the use is detected (in the case of the variant presented in Figure 4):

- Time 1: hot water conveyed in the heater branch (but not in component 34) o electric water pump powered o three-way valve positioned so that the water present in the engine 2 arrives in the air heater branch

31.

- Time 2: hot water transferred from the air heater branch 31 to the storage tank 5 o electric water pump fed o three-way valve positioned so that the water present in the air heater branch 31 arrives in the branch 34 having the hydraulic tank 5.

Since the volume of water in the air heater branch may be less than the volume of water in the hydraulic reservoir, the procedure (time + time 2) must be carried out several times in the case of the variant presented in FIG. hydraulic bottle is much simpler in the case of the variant shown in Figure 5.

For the restitution of the energy the reverse procedure must be followed. For a request for heating the cabin:

If a request to start the vehicle without a heat engine (driver request or vehicle programming) is coupled with a heating demand, it can be provided if the thermal storage is sufficiently charged. In this case, the operating mode of the engine water circuit used is "the dissociated circuit", that is to say that the parts 21 and 31 of the hydraulic circuit are dissociated.

In other living conditions, the heating of the cabin is carried out according to the "conventional" operation that the engine is running or stopped (engine providing calories to the heater)

For a demist mode request:

In this condition of life, and in particular in winter when the engine is stopped, to ensure a defogging function, circulating water is maintained in the heater by the electric water pump 32, which allows to maintain a supply of water. hot air via the heater. Advantageously with the hydraulic reservoir, this phenomenon can be amplified without the addition of an additional actuator.

Claims

1. A vehicle air conditioning system, in particular a hybrid motor vehicle, equipped with a heat engine (2) and a hydraulic circuit, said system comprising an evaporator (41), a heater (3), means for supplying power to a vehicle, the air heater at the outlet of the evaporator, characterized in that:

the system comprises means (33, 34, 35) for separating the part of the hydraulic circuit (21) supplying the heat engine from the part of the hydraulic circuit (31) supplying the heater in that:

- The part of the hydraulic supply circuit of the heater comprises a hydraulic tank (5).

2. Climate system according to claim 1, characterized in that the hydraulic reservoir contains brine.

3. Air conditioning system according to one of claims 1 or 2, characterized in that the hydraulic supply circuit of the heater comprises a parallel circuit in which is incorporated the hydraulic reservoir.

4. Air conditioning system according to one of claims 1 to 3, characterized in that the means for dissociating the hydraulic supply circuit of the engine, the hydraulic supply circuit of the heater, comprises two hydraulic ducts mounted in parallel (33,34,35).

5. Air conditioning system according to one of claims 1 to 4, characterized in that the means for dissociating the hydraulic supply circuit of the engine and the hydraulic supply circuit of the heater comprises a three-way valve ( 60, 61) for supplying the hydraulic circuit for supplying the heater with a closed circuit.

6. Air conditioning system according to one of claims 1 to 5, characterized in that the means for dissociating the hydraulic supply circuit of the engine and the hydraulic supply circuit of the heater comprises at least one anti-slip valve. return.

7. Air conditioning system according to one of claims 1 to 6, characterized in that the hydraulic supply circuit of the heater comprises an electric pump.

8. An air conditioning system according to one of claims 1 to 7, characterized in that it comprises means for varying the supply air flow rate of the heater.

9. The air conditioning system according to one of claims 1 to 8, characterized in that the hydraulic supply circuit of the engine comprises bypass means.

10. The air conditioning system according to one of claims 7 and 8, characterized in that it further comprises control means of the hydraulic circuits (21, 31), the electric pump (32) and means for varying the supply air flow of the heater (3).

11. Air conditioning system according to claim 10, characterized in that the management of the three-way valve, the pump and the air conditioning unit is carried out according to the ambient conditions, the customer requests, or even the driving conditions of the vehicle.