Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H1/00—Heating, cooling or ventilating [HVAC] devices
  • B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
  • B60H1/00735—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models
  • B60H1/00785—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models by the detection of humidity or frost

Definitions

• Air conditioning device for vehicles and method of implementing such a device
• the present invention relates to the technical field of air conditioning systems for vehicles, and more particularly to an air conditioning system providing both cooling and heating of the air in the passenger compartment of the vehicle.
• the present invention also relates to a method of implementing such systems.
• Air conditioning systems usually include an external heat exchanger, placed outside the passenger compartment of the vehicle, an internal heat exchanger, placed inside the passenger compartment of the vehicle, a first duct connecting the two exchangers and on which is placed a compressor, and a second duct connecting the two exchangers and on which is placed a regulator.
• the assembly formed by the two exchangers, the two lines, the compressor and the holder, is called the refrigeration loop. There circulates a refrigerant.
• An air conditioning system of the type described above can provide heating or cooling of the air in the passenger compartment of the vehicle when it also has means for reversing the direction of circulation of the refrigerant inside. of the refrigeration loop.
• the refrigeration loop is then said to be reversible.
• the refrigerant passes through the exterior exchanger, the compressor, the interior exchanger, then the holder, the interior exchanger cools the air passing through it, which is sent to the passenger compartment of the vehicle.
• the expansion valve, the internal exchanger, then the compressor the air passing through the exchanger is heated before being directed towards the passenger compartment.
• the interior exchanger which acts as an evaporator, becomes charged with water, in particular at its walls, by condensation of a part of the humidity contained in the treated air.
• the interior exchanger becomes condenser, and causes the rapid evaporation of the water that has accumulated on its walls, this air sent towards the passenger compartment can cause extremely rapid fogging of the glass surfaces of the vehicle, this phenomenon being called "flash-fogging", a source of discomfort for the driver of the vehicle.
• One solution consists in using an air conditioning system comprising two interior exchangers, one dedicated to heating and the other to cooling the air in the passenger compartment.
• Publication DE 3 907 201 describes such a system, in which a first indoor exchanger operates as a condenser to cool the air passing through it, and a second indoor exchanger operates as an evaporator to heat the air passing through it.
• a first indoor exchanger operates as a condenser to cool the air passing through it
• a second indoor exchanger operates as an evaporator to heat the air passing through it.
• the system described in the publication DE 3 907 201, if it makes it possible to avoid the problem of "flash-fogging", requires an additional internal exchanger which can represent a non-negligible additional cost.
• the location necessary for the installation of the second interior exchanger may prove to be incompatible with the space occupation constraints associated with the vehicle, in particular in the motor vehicle industry.
• the present invention aims to eliminate the problem of "flash-fogging" of an air conditioning system which can both heat or cool the air in the passenger compartment of a vehicle and comprising only a single exchanger inside.
• a method of implementing a system for heating or cooling the air in the passenger compartment of a vehicle equipped with a windshield by supplying air into the passenger compartment having passed through a exchanger belonging to a refrigeration loop, comprising the steps of measuring the temperature of the air leaving the exchanger, measuring the humidity of the air leaving the exchanger, determining the dew temperature of the air leaving the exchanger at from said temperature and humidity, determine the temperature of the windshield, compare the dew temperature with the temperature of the windshield, and cause the heating of the air in the passenger compartment to stop when the dew temperature is higher at the temperature of the windshield.
• stopping the heating of the air in the passenger compartment consists in deflecting the air passing through the exchanger towards the exterior of the vehicle.
• the air is deflected for a determined period, or until the dew temperature is lower than the temperature of the windshield.
• stopping the heating of the air in the passenger compartment consists in stopping the operation of the refrigeration loop.
• the stopping of the operation of the refrigeration loop is for a determined period, or continues until the dew temperature is lower than the temperature of the windshield. According to another characteristic of the invention, the stop of operation of the refrigeration loop is final until the next start of the vehicle.
• the invention also provides a device for conditioning the air in the passenger compartment of a vehicle having a windshield, of the type comprising a first exchanger placed inside the passenger compartment, a second exchanger placed outside the passenger compartment, first conduits, for the passage of a refrigerant, between the first exchanger and the second exchanger, second conduits , for the passage of the refrigerant, between the first exchanger and the second exchanger, a compressor placed on the first conduits, a pressure reducer placed on the second conduits, reversing means for reversing the direction of circulation of the fluid in the first and second conduits, control means electrically connected to the compressor, and means for discharging at least part of the water present at the first exchanger, said device further comprising first measurement means emitting a signal representative of the temperature of the air leaving the first exchanger, of the second measurement means emitting a signal representative of the humidity of the air leaving as the first exchanger, the control means being electrically connected to the first and second measuring means, being adapted to determine the dew point temperature of
• the first exchanger is placed in a main pipe, connected at one end to the passenger compartment, and at a second end outside the vehicle, the evacuation means comprising at least one pipe.
• secondary connected at a first end to the main pipe, and at a second end outside the vehicle, and at least one flap adapted to seal, at least in part, alternatively the secondary pipe, or the main pipe .
• said shutter closes the main pipe downstream of the first exchanger according to the direction of air circulation in the main pipe.
• FIG. 1 schematically represents an air conditioning system according to a first embodiment of the invention
• FIG. 2 represents the diagram of the steps of a first method implementing a first embodiment of the device according to the invention
• FIG. 3 shows the diagram of the steps of a second method implementing a second embodiment of the device according to the invention.
• - Figure 4 shows the diagram of the steps of a third method implementing a second embodiment of the device according to the invention.
• An air conditioning system 10 shown in FIG. 1, intended to heat or cool the air sent into the passenger compartment (not shown) of a vehicle, consists of a refrigeration loop comprising an internal exchanger 12, connected by first and second lines, respectively
• a compressor 14, associated with reversing means 19, is placed on the first line 16, while a pressure reducer 15 is placed on the second line 17.
• a refrigerant circulates inside the refrigeration loop.
• the reversing means 19 making it possible to reverse the direction of circulation of the refrigerant in the refrigeration loop.
• the internal exchanger 12 is placed in a main pipe 11 connected, at a first end, to an air inlet mouth (not shown) overlooking the outside of the vehicle, and, at a second end, to the passenger compartment (possibly by dividing into several pipes). Outside air is sucked in, through the air inlet mouth, by a blower 25, placed in the main pipe 11, then passes through the indoor exchanger 12 to be finally expelled into the passenger compartment of the vehicle.
• the interior exchanger 12 When the refrigerant passes through the interior exchanger 12, the pressure reducer 15, the exterior exchanger 13, then the compressor 14, the interior exchanger 12 operates as an evaporator and cools the air passing through it.
• the compressor 14 When the refrigerant passes through the interior exchanger 12, the compressor 14, the exterior exchanger 13, then the expansion valve 15, the interior exchanger 12 operates as an evaporator and heats the air passing through it.
• a control unit 20 is adapted to control the reversing means 19, thus controlling the operating mode of the refrigeration loop as a heat pump or as an air cooler.
• the control unit 20 also controls the compressor 14 in order, for example, to control the power delivered by the interior exchanger 12 when the refrigeration loop operates as a heat pump.
• the control unit 20 is connected to a first temperature sensor
• the first temperature sensor 22 placed downstream of the interior exchanger 12, according to the direction of air circulation in the main pipe 11.
• the control unit 20 is connected to a humidity sensor 23, placed inside the main pipe 11, downstream of the indoor exchanger 12 according to the direction of air circulation in the main pipe 11.
• the humidity sensor 23 transmits to the control unit 20 a signal representative of the relative humidity rate H ech downstream of the indoor exchanger 12.
• the control unit 20 is connected to a second temperature sensor 21, placed outside the vehicle.
• the second temperature sensor 21 transmits to the control unit 20 a signal representative of the temperature outside the windshield T ext .
• the control unit 20 is further adapted to determine the temperature of the windshield T pb .
• the control unit 20 can calculate an estimate of the temperature of the windshield T pb from the signals emitted by the temperature sensor 21 measuring the temperature of the air outside the vehicle T a , d a temperature sensor (not shown) measuring the temperature of the air inside the passenger compartment, and a vehicle speed sensor, according to a method known to those skilled in the art.
• the main pipe 11 is provided with condensate discharge means 18, which consist of a secondary pipe 27 which connects the main pipe 11, substantially at the level of the internal exchanger 12, outside the vehicle.
• condensate discharge means 18, consist of a secondary pipe 27 which connects the main pipe 11, substantially at the level of the internal exchanger 12, outside the vehicle.
• a flap 26, maneuvered by actuating means 28, can come, in a first extreme position, called the closed position, to close off the end of the secondary pipe 27 leading to the main pipe 11.
• the shutter 26 closes, at least in part, the main pipe 11 and forces the air blown by the blower 25 to pass through the secondary pipe 27.
• the actuation means 28 of the shutter 26 are controlled by the control unit 20.
• the main pipe 11 is not equipped with condensate discharge means 18, all the other elements being identical elsewhere.
• a first method of implementing the first embodiment of the device is shown in FIG. 2.
• the control unit receives from the second temperature sensor 21 a signal representative of the temperature T at at exterior of the vehicle.
• the control unit 20 compares the value of the temperature outside the vehicle T at with a threshold temperature value T threshold stored in the control unit 20. If the temperature at outside the vehicle r at is above the threshold temperature T threshold , we return to step 30.
• step 32 the control unit 20 then controls the operation of the refrigeration loop in a heat pump, possibly controlling the reversing means 19 and the compressor 14.
• step 33 the control unit calculates, according to a method known to man of the trade, the value of the dew temperature T ros ⁇ e downstream of the indoor exchanger 12, from the temperature T ech and the humidity H ech downstream of the indoor exchanger 12.
• step 34 the control unit compares the dew temperature T dew to the temperature of the windshield T pb , which is measured or calculated as explained above. In the case where the dew temperature T dew is lower than the temperature of the windshield T pb , the heating of the passenger compartment continues to step 36. In the case where the dew temperature T dew is higher than the temperature of the windshield T pb , the control unit 20 controls the condensate evacuation means 18, so as to evacuate part of the water present on the interior exchanger 12. To do this, the control unit 20 controls opening of the shutter 26, and keeping the shutter 26 in position open for a fixed period. The air passing through the interior exchanger 12, charged with humidity, is evacuated outside the vehicle.
• the opening time of the shutter 26 can be determined experimentally so as to ensure sufficient evacuation of the water present on the indoor exchanger 12. During this time, the control unit controls the compressor 14 so that the power released by the indoor heat exchanger is optimal for charging the air passing through it with humidity, allowing the evacuation of a maximum quantity of water.
• the opening time of the flap 26 can also be extended until the dew temperature T dew becomes lower than the temperature of the windscreen T pb , without however exceeding a determined maximum duration.
• a second method of implementing the second embodiment of the device according to the invention, shown in FIG. 3, comprises steps 40,41,42,43,44, which are respectively identical to steps 30,31,32, 33.34.
• the control unit 20 compares the dew temperature T dew with the temperature of the windshield T pb . In the case where the dew temperature T dew is lower than the temperature of the windshield T pb , the heating of the passenger compartment continues to step 46. In the case where the dew temperature T ros ⁇ e is higher than the temperature of the windshield T pb , the control unit 20, in step 45, controls the compressor 14 to stop the operation of the refrigeration loop in heat pump mode. The stop can be prolonged for a fixed duration, or until the dew temperature T dew becomes lower than the windshield temperature T pb , without however exceeding a maximum duration
• a third method of implementing the second embodiment of the device according to the invention, represented in FIG. 4, comprises the steps 50,51,52,53,54,55,56 identical to the respective steps 40,41,42 , 43,44,45,46 of the second method of implementing the second embodiment of the device described above.
• step 55 we go to step 57 where the control unit 20 prohibits the starting of the refrigeration loop as a heat pump until a new use of the vehicle.
• the present invention is in no way limited to the embodiment described and illustrated which has been given only by way of example. On the contrary, the invention includes all the technical equivalents of the means described and their combinations if these are carried out according to the spirit.
• the reversing means can be integrated into the compressor.

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• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Air-Conditioning For Vehicles (AREA)

Applications Claiming Priority (3)

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• 2000
  • 2000-04-28 FR FR0005454A patent/FR2808244B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-20 WO PCT/FR2001/001222 patent/WO2001083244A1/fr not_active Application Discontinuation
  • 2001-04-20 US US10/258,742 patent/US7055336B2/en not_active Expired - Fee Related
  • 2001-04-20 EP EP01928021A patent/EP1276623A1/de not_active Withdrawn

Non-Patent Citations (1)

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