Air-conditioning device for vehicles, and method therefor

• US 20040182094A1
• Filed: 04/23/2004
• Published: 09/23/2004
• Est. Priority Date: 04/28/2000
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated), Renault
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated), Renault
• Inventors: Olivier, Gerard, Menager, Jean-Luc, Pittion, Laurent
• Granted Patent: US 7,055,336 B2
• Time in Patent Office: Days
• US Class Current: 62/176.5
• CPC Class Codes: B60H 1/00785 by the detection of humidity or frost

Abstract

The invention concerns a method using a system (10) for heating or cooling air in a motor vehicle passenger compartment provided with a windscreen, by input into the passenger compartment air which has passed through an exchanger (12) comprised in a refrigerant loop. The invention is characterized in that it comprises steps which consist in measuring the temperature of the air leaving the exchanger (12), measuring the humidity of the air leaving the exchanger (12), determining the dew point of the air leaving the exchanger (12) based on said temperature and humidity, determining the windscreen temperature, comparing the dew point with the windscreen temperature and stopping the heating of air in the passenger compartment when the dew point is higher than the windscreen temperature.

Claims

1. A method for use of a system (10) for heating or cooling the air of a passenger compartment of a vehicle equipped with a windshield, wherein air that has passed through an exchanger (12) belonging to a refrigerant loop is supplied to the passenger compartment, the method being characterized in that it comprises the steps of measuring the temperature of the air exiting the exchanger (12), measuring the humidity of the air exiting the exchanger (12), determining the dew point of the air exiting the exchanger (12) from the said temperature and humidity, determining the windshield temperature, comparing the dew point with the windshield temperature, and stopping the heating of the air in the passenger compartment when the dew point is higher than the windshield temperature.

2. A method according to claim 1, characterized in that the heating of the air in the passenger compartment is stopped by diverting the air passing through the exchanger (12) to the outside of the vehicle.

3. A method according to claim 2, characterized in that the air is diverted for a specified duration.

4. A method according to claim 2, characterized in that the air is diverted until the dew point becomes lower than the windshield temperature.

5. A method according to claim 4, characterized in that the diversion of the air is less than a specified maximum duration.

6. A method according to claim 1, characterized in that the heating of the air in the passenger compartment is stopped by stopping the operation of the refrigerant loop.

7. A method according to claim 6, characterized in that the stoppage of the operation of the refrigerant loop lasts for a specified duration.

8. A method according to claim 6, characterized in that the stoppage of the operation of the refrigerant loop is continued until the dew point is lower than the windshield temperature.

9. A method according to claim 8, characterized in that the diversion of the air is less than a specified maximum duration.

10. A method according to claim 6, characterized in that the operation of the refrigerant loop is stopped and disabled until the next restart of the vehicle.

11. A device (10) for heating or cooling the air of the passenger compartment of a vehicle equipped with a windshield, of the type comprising a first exchanger (12) installed inside the passenger compartment, a second exchanger (13) installed outside the passenger compartment, first conduits (16) for conveying a refrigerant fluid between the first exchanger (12) and the second exchanger (13), second conduits (17) for conveying the refrigerant fluid between the first exchanger (12) and the second exchanger (13), a compressor (14) installed in the first conduits (16), a pressure-reducing valve (15) installed in the second conduits (17), reversing means (19) for reversing the direction of circulation of the fluid in the first and second conduits (16, 17), control means (20) connected electrically to the compressor (14), and means (18) for evacuation of at least part of the water present in the first exchanger (12), characterized in that it is equipped with first measuring means (22) that transmit a signal representative of the temperature of the air exiting the first exchanger (12), second measuring means (22) that transmit a signal representative of the humidity of the air exiting the first exchanger (12), the control means (20) being connected electrically to the first and second measuring means (22, 23, 21) and being designed to determine the dew point of the air exiting the first exchanger (12) from the signals transmitted by the first and second measuring means (22, 23), to determine the windshield temperature, to compare the said dew point and the windshield temperature, and to activate the evacuation means (18) when the dew point is higher than the windshield temperature.

12. A device (10) according to claim 11, characterized in that the first exchanger (12) is installed in a main duct (11) communicating at one end with the passenger compartment and at a second end with the outside of the vehicle, the evacuation means (18) comprising at least one secondary duct (27) communicating at a first end with the main duct (11) and at a second end with the outside of the vehicle, and at least one damper (26) designed to shut off the secondary duct (27) or the main duct (11) at least partly, in alternating manner.

13. A device (10) according to claim 12, characterized in that the said damper (26) shuts off the main duct (11) downstream from the first exchanger (12) as defined by the direction of circulation of the air in the main duct (11).